KR20230020402A - Acrylic rubber with excellent roll processability, strength properties and water resistance - Google Patents

Abstract

An acrylic rubber excellent in roll processability, strength characteristics and water resistance is provided. The acrylic rubber according to the present invention has a (meth)acrylic acid ester as a main component and a dimethylformamide solvent as a developing solvent. The absolute molecular weight measured by the GPC-MALS method and the weight average molecular weight (Mw) based on the absolute molecular weight distribution is 1 million or more, the ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) is 3.4 or more, the amount of ash is 0.4% by weight or less, and the total amount of sodium, magnesium, calcium, phosphorus and sulfur in the ash is 80% or more by weight.

Description

Acrylic rubber with excellent roll processability, strength properties and water resistance

The present invention relates to an acrylic rubber, a method for producing the same, a rubber composition, and a crosslinked rubber, and more particularly, an acrylic rubber having excellent roll processability and excellent strength characteristics and water resistance of the crosslinked product, a method for producing the same, and a method for producing the same. It relates to a rubber composition containing acrylic rubber and a crosslinked rubber product formed by crosslinking it.

Acrylic rubber is a polymer containing acrylic acid ester as a main component, and is generally known as a rubber having excellent heat resistance, oil resistance and ozone resistance, and is widely used in automobile-related fields and the like.

For example, in Patent Document 1 (Pamphlet of International Publication No. 2019/188709), monomer components composed of ethyl acrylate, butyl acrylate, methoxyethyl acrylate and monobutyl fumarate, water and sodium lauryl sulfate are charged, degassed under reduced pressure and After repeating nitrogen substitution, sodium aldehyde sulfoxylate and cumene hydroperoxide, an organic radical generator, are added to initiate emulsion polymerization under normal pressure and room temperature, and emulsion polymerization is performed until the polymerization conversion rate reaches 95% by weight, followed by calcium chloride Disclosed is a method for producing acrylic rubber by coagulating an aqueous solution, filtering it with a wire mesh, and then dehydrating and drying it with an extrusion dryer having a screw. However, the acrylic rubber obtained by this method has problems in that roll processability and Banbury processability are extremely poor, and storage stability and water resistance are also poor.

In Patent Document 2 (Japanese Unexamined Patent Publication No. 2019-119772), monomer components consisting of ethyl acrylate, butyl acrylate, methoxyethyl acrylate and monobutyl maleate are pure water and sodium lauryl sulfate and polyoxyethylene dodecyl ether as emulsifiers. After preparing a monomer emulsion, a portion of the monomer emulsion is put into a polymerization reaction tank and cooled to 12° C. under a nitrogen stream, and then the remainder of the monomer emulsion, ferrous sulfate, sodium ascorbate, and potassium persulfate as an inorganic radical generator The aqueous solution was continuously added dropwise over 3 hours, and then kept at 23°C for 1 hour to continue emulsion polymerization, and after the polymerization conversion reached 97% by weight, the temperature was raised to 85°C, followed by continuous addition of sodium sulfate. Water-containing crumb was obtained by coagulation and filtration separation, and after the water-containing crumb was washed with water 4 times, acid washed once, and purified water washed once, acrylic rubber was continuously produced in a sheet form with an extrusion dryer having a screw, and hexamethylenediamine carbamate A method of crosslinking with an aliphatic polyvalent amine compound such as the like is disclosed. However, the sheet-like acrylic rubber obtained by this method has problems of poor roll processability and poor water resistance of the crosslinked product.

In Patent Document 3 (Japanese Unexamined Patent Publication No. 1-135811), a monomer component composed of ethyl acrylate, caprolactone addition type acrylic acid ester, cyanoethyl acrylate and vinyl chloroacetate and n-dodecylmercaptan as a chain transfer agent is disclosed. 1/4 of the monomer mixture was emulsified with sodium lauryl sulfate, polyethylene glycol nonylphenyl ether and distilled water, sodium sulfite and ammonium persulfate as an inorganic radical generating agent were added to initiate polymerization, and the remaining temperature was maintained at 60°C. A negative monomer mixture and 2% ammonium persulfate aqueous solution were added dropwise for 2 hours, and the latex having a polymerization conversion rate of 96 to 99%, which was continued for 2 hours after dropping, was added to an aqueous sodium chloride solution at 80 ° C to solidify, and then washed thoroughly with water and dried. A method of preparing acrylic rubber and crosslinking it with sulfur is disclosed. However, the acrylic rubber obtained by this method has problems such as poor roll processability and storage stability, and poor strength characteristics and water resistance of the crosslinked product.

In Patent Document 4 (Japanese Unexamined Patent Publication No. 2018-168343), monomer components consisting of ethyl acrylate, butyl acrylate and monobutyl fumarate, pure water, sodium lauryl sulfate, polyethylene glycol monostearate, and n-dodecylmercaptan as a chain transfer agent A monomer emulsion consisting of is prepared, and then, 1 part of the monomer emulsion and pure water are put into a polymerization reaction tank, cooled to 12 ° C., and the remainder of the monomer emulsion, ferrous sulfate, sodium ascorbate, and as an inorganic radical generator Potassium sulfate was continuously added dropwise over 2.5 hours, then maintained at 23°C to continue the reaction for 1 hour, then industrial water was added to raise the temperature to 85°C, followed by continuous addition of sodium sulfate at 85°C to solidify the water A method of obtaining crumb, washing with pure water three times and then drying with a hot air dryer to prepare acrylic rubber and crosslinking with 2,2-bis[4-(4-aminophenoxy)phenyl]propane is disclosed. However, although the acrylic rubber obtained by this method has excellent stress relaxation properties and extrusion processability, it has problems such as insufficient roll processability and storage stability, and poor strength characteristics and water resistance of the crosslinked product.

In Patent Document 5 (Japanese Unexamined Patent Publication No. 9-143229), a monomer mixture composed of ethyl acrylate, special acrylate and monochlorovinyl acetate, sodium lauryl sulfate as an emulsifier, n-octyl mercaptan and water as a chain transfer agent are After adding to the reaction vessel, replacing with nitrogen, adding ammonium hydrogen sulfite and sodium persulfate as an inorganic radical generating agent to initiate polymerization, and copolymerizing at 55 ° C. for 3 hours at a reaction conversion rate of 93 to 96% to prepare acrylic rubber A method of crosslinking with sulfur is disclosed. However, the acrylic rubber obtained by this method has a problem of poor storage stability and poor strength characteristics and water resistance of the crosslinked product.

Patent Document 6 (Japanese Unexamined Patent Publication No. 62-64809) discloses 50 to 99.9% by weight of at least one compound of acrylic acid alkyl esters and acrylic acid alkoxyalkyl esters, dihydrodicyclopentane of an unsaturated carboxylic acid having a radical reactive group. A copolymer having a monomer composition comprising 0.1 to 20% by weight of a vinyl group-containing ester and 0 to 20% by weight of at least one of other monovinyl, monovinylidene, and monovinylene unsaturated compounds, wherein tetrahydrofuran is used as a developing solvent Characterized in that the number average molecular weight (Mn) in terms of one polystyrene is 200,000 to 1.2 million, and the ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) is 10 or less, characterized by processability and compression set Disclosed is an acrylic rubber having excellent tensile strength and capable of sulfur vulcanization. In addition, the number average molecular weight (Mn) is 200,000 to 1,000,000, preferably 200,000 to 1,000,000, and when Mn is less than 200,000, the physical properties and processability of the vulcanized product are deteriorated, and when it exceeds 1.2 million, processability is deteriorated, and weight Regarding the ratio (Mw/Mn) of the average molecular weight (Mw) to the number average molecular weight (Mn), it has been described that when the ratio exceeds 10, the compression set becomes large, which is not preferable. Specific examples thereof include monomer components including ethyl acrylate or radical crosslinkable dihydrodicyclopentenyl acrylate, sodium lauryl sulfate as an emulsifier, potassium persulfate as an inorganic radical generating agent, and thioglycolic acid as a molecular weight regulator. Octyl or t-dodecylmercaptan was added in varying amounts, and the number average molecular weight (Mn) was 53 to 1.15 million, the weight average molecular weight (Mw) was 3.54 to 6.26 million, and the weight average molecular weight (Mw) and number average molecular weight (Mn ) A manufacturing method is disclosed in which acrylic rubber having a ratio (Mw/Mn) of 4.7 to 8 is polymerized, solidified in an aqueous calcium chloride solution, washed with water sufficiently, and directly dried. And, when the amount of chain transfer agent is small, the number average molecular weight (Mn) of the obtained acrylic rubber is high at 5,000,000, and the ratio (Mw/Mn) between the weight average molecular weight (Mw) and the number average molecular weight (Mn) narrows to 1.4, When the amount of chain transfer agent is large, the number average molecular weight (Mn) is as small as 200,000, and the ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) is extremely widened to 17, as shown in Examples and Comparative Examples. it's gone However, since the acrylic rubber obtained by this method has poor compression set resistance and storage stability and contains a radical reactive group, even if an appropriate molecular weight distribution (Mw/Mn) is obtained in a polymerization reaction using a radical generator, the molecular weight (Mw, Mn) was large and too complicated, and there was also a problem that roll workability and Banbury workability were not sufficient. Further, in the crosslinking reaction, the acrylic rubber obtained by the present method is added with sulfur and a vulcanization accelerator as a crosslinking agent and kneaded with a roll, followed by 100 kg/cm ² vulcanization press at 170°C for 15 minutes and a gear oven at 175°C for 4 hours. As a result, long-term crosslinking is required, and the obtained crosslinked product also has poor compression set resistance, water resistance, and strength characteristics, and also has problems such as poor change in physical properties after thermal deterioration.

International Publication No. 2019/188709 Pamphlet Japanese Unexamined Patent Publication No. 2019-119772 Japanese Unexamined Patent Publication No. 1-135811 Japanese Unexamined Patent Publication No. 2018-168343 Japanese Unexamined Patent Publication No. 9-143229 Japanese Unexamined Patent Publication No. 62-64809

The present invention has been made in view of the actual state of the prior art, and is excellent in roll processability and also highly excellent in strength characteristics and water resistance of a crosslinked product, a method for producing the same, a rubber composition containing the acrylic rubber, and crosslinking thereof It is an object of the present invention to provide a cross-linked rubber product formed by

As a result of intensive research in view of the above problems, the inventors of the present invention have found that acrylic rubber contains (meth)acrylic acid ester as a main component, and also has an absolute molecular weight measured by the GPC-MALS method and a weight average molecular weight (Mw) of absolute molecular weight distribution And the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn) (Mw/Mn) is specified, and the amount of ash and the amount of a specific component in the ash are specified, so that roll processability is excellent, and the crosslinked product has strength characteristics and water resistance I found this highly excellent.

Regarding the roll processability of acrylic rubber, the inventors of the present invention found that the number average molecular weight (Mn) measured by the GPC-MALS method and the ratio (Mw/Mn) of the weight average molecular weight (Mw) and the number average molecular weight (Mn) are highly related. It was found that roll workability can be remarkably improved without impairing strength characteristics when each is within a specific range. In particular, the larger the ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn), the better the roll workability, but have a specific number average molecular weight (Mn) and also have a specific number average molecular weight (Mw) and number average It was difficult to produce an acrylic rubber having a wide molecular weight (Mn) ratio (Mw/Mn), but the present inventors found that it could be achieved by adding a chain transfer agent batchwise during polymerization without initially adding it. The present inventors also found that the weight average molecular weight (Mw) and the number average molecular weight (Mw) and number average molecular weight ( It was found that roll workability was further improved by greatly widening the ratio (Mw/Mn) of Mn).

The present inventors have further found that the amount of ash and ash components in acrylic rubber greatly affect the water resistance of acrylic rubber. In emulsion polymerization, it is difficult to reduce the ash content of acrylic rubber, which uses a large amount of emulsifier and coagulant. and, as a result, it was found that the water resistance of acrylic rubber can be remarkably improved. In particular, the inventors of the present invention increased the ratio of the specific particle diameter of the hydrous crumb generated in the solidification step and washed, dehydrated, and dried to damage the properties such as roll workability, strength characteristics, and compression set resistance of the obtained acrylic rubber. It was found that the water resistance can be improved remarkably without making it. In addition, the present inventors have found that when a specific emulsifier is used in emulsion polymerization of acrylic rubber, or when a specific coagulant is used in coagulation of an emulsion polymerization solution, the water resistance of acrylic rubber is excellent and the releasability to a mold or the like is remarkably increased. paid

The present inventors have also found that acrylic rubbers having ion-reactive groups or specific reactive groups have excellent roll workability, strength characteristics and water resistance, as well as short-time crosslinking properties and compression set resistance.

The inventors of the present invention, in GPC measurement of acrylic rubber, in particular, acrylic rubber having the reactive group, used for GPC measurement of radical reactive acrylic rubber copolymerized with ethyl acrylate or dihydrodicyclopentenyl acrylate of the prior art However, it was not possible to measure each molecular weight and molecular weight distribution clearly and reproducibly because tetrahydrofuran could not be sufficiently dissolved, and it was not possible to measure each molecular weight and molecular weight distribution clearly and reproducibly. It was found that the roll processability of acrylic rubber and the water resistance, strength characteristics and compression set resistance characteristics of a crosslinked product can be highly balanced by specifying each characteristic value.

The present inventors also found that by specifying the methyl ethyl ketone insoluble content of acrylic rubber, it was excellent in roll processability, strength characteristics and water resistance as well as excellent Banbury processability. The amount of methyl ethyl ketone insoluble in acrylic rubber is generated during the polymerization reaction, and it is difficult to control because it increases rapidly when the polymerization conversion ratio is increased to improve strength characteristics. What can be suppressed, and the rapidly increased methyl ethyl ketone insoluble content is melt-kneaded acrylic rubber in a state in which the rapidly increased methyl ethyl ketone insoluble content does not contain substantially water (less than 1% by weight) in a screw type twin screw extrusion dryer, and then extruded and dried. Methyl ethyl rapidly increased It was found that the Banbury workability can be remarkably improved without impairing the roll workability due to the loss of ketone insoluble components.

The present inventors also found that, by specifying the specific gravity of the acrylic rubber, roll workability, strength characteristics and water resistance were excellent, and storage stability was also excellent. Acrylic rubber, especially acrylic rubber having an ionic reactive group or a reactive group that reacts with a crosslinking agent such as a carboxyl group, an epoxy group or a chlorine atom, is tacky and difficult to escape air. Although the storage stability is deteriorated by entrainment (specific gravity decreases), the crumb-like acrylic rubber is compressed under high pressure with a baler or the like to bale, so that the air can be slightly removed and the storage stability can be improved, preferably is extruded and dried under reduced pressure with a screw-type twin-screw extrusion dryer to extrude into an air-free sheet, or, if necessary, laminated with an extruded sheet-like acrylic rubber, which contains almost no air. It was found that a veil-like acrylic rubber having a high specific gravity and significantly improved storage stability could be produced. The present inventors have further found that the specific gravity with the air content taken into account can be measured according to JIS K6268 Crosslinked Rubber-Method A of Density Measurement using the difference in buoyancy. In addition, it was found that the storage stability of acrylic rubber can be further improved by specifying the pH.

The present inventors also found that the scorch stability of the rubber composition can be significantly improved by increasing the cooling rate of the dried acrylic rubber without impairing properties such as roll processability, water resistance, strength characteristics and compression set resistance characteristics. paid

The present inventors also found that the monomer composition of acrylic rubber, the ratio of z average molecular weight (Mz) and weight average molecular weight (Mw) (Mz/Mw), complex viscosity at 60°C ([η]60°C), 100°C By specifying the ratio ([η] 100° C./[η] 60° C.) of the complex viscosity at ([η] 100° C.) and the complex viscosity ([η] 60° C.) at 60° C., and the shape, further , roll workability, strength characteristics, and water resistance were highly improved, and it was found that, by using a polyvalent organic compound as a crosslinking agent, the crosslinkability in a short time and each characteristic of the resulting crosslinked rubber product were greatly improved.

The present inventors also emulsified a specific monomer component with water and an emulsifier, and then initiated emulsion polymerization in the presence of a redox catalyst composed of an inorganic radical generator such as potassium persulfate and a reducing agent, without initially adding a chain transfer agent. Emulsion polymerization by adding batchwise during polymerization, solidification of the obtained emulsion polymerization solution under specific conditions, washing of the hydrous crumb generated in the coagulation reaction with warm water, and drying of the hydrous crumb after dehydration after washing It was found that the roll processability, strength characteristics and water resistance of acrylic rubber are highly balanced by coexisting high molecular weight components and low molecular weight components of acrylic rubber that can be produced by a wide molecular weight distribution and by setting the ash content of a specific component. .

The present inventors also found that by using a specific extrusion dryer to melt-knead and dry acrylic rubber under high shear conditions, it was possible to manufacture acrylic rubber with further improved roll workability, strength characteristics and water resistance. Further, it was found that by specifying the post-addition of the reducing agent and the polymerization temperature, it was possible to produce an acrylic rubber having better balance in roll processability, strength characteristics, and water resistance.

The present inventors also found that, in the rubber composition comprising the acrylic rubber, filler and crosslinking agent of the present invention, by blending carbon black or silica as the filler, roll workability, Banbury workability and crosslinkability in a short time are excellent, and crosslinking It was found that the water resistance, strength characteristics and compression set resistance of water were highly excellent. The present inventors further found that, as the crosslinking agent, it is preferable to be an organic compound, a polyvalent compound or an ionic crosslinking compound. It was found that, by being a polyvalent ion organic compound having multiple ions, roll processability, Banbury processability, and crosslinkability in a short time were excellent, and the crosslinked product was highly excellent in water resistance, strength characteristics, and compression set resistance.

The present inventors came to complete this invention based on these knowledge.

In this way, according to the present invention, the absolute molecular weight measured by the GPC-MALS method using (meth)acrylic acid ester as the main component and the dimethylformamide-based solvent as the developing solvent and the weight average molecular weight (Mw) by the absolute molecular weight distribution is 1 million or more, the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn) (Mw/Mn) is 3.4 or more, the amount of ash is 0.4% by weight or less, and the total amount of sodium, magnesium, calcium, phosphorus and sulfur in the ash This 80% by weight or more of acrylic rubber is provided.

In the acrylic rubber of the present invention, the ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) is preferably 3.5 or more.

In the acrylic rubber of the present invention, the ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) is preferably in the range of 3.7 to 6.5.

The acrylic rubber of the present invention preferably has a reactive group.

In the acrylic rubber of the present invention, the reactive group preferably has an ion reactive group.

In the acrylic rubber of the present invention, the reactive group is preferably at least one reactive group selected from the group consisting of a carboxyl group, an epoxy group and a chlorine atom.

In the acrylic rubber of the present invention, the acrylic rubber comprises a bonding unit derived from at least one (meth)acrylic acid ester selected from the group consisting of (meth)acrylic acid alkyl esters and (meth)acrylic acid alkoxyalkyl esters, and a reactive group-containing monomer. It is preferable that it consists of a binding unit derived from, and a binding unit derived from other monomers.

In the acrylic rubber of the present invention, the ratio (Mz/Mw) of the z-average molecular weight (Mz) to the weight-average molecular weight (Mw) is preferably in the range of 1.3 to 3.

In the acrylic rubber of the present invention, it is preferable that the methyl ethyl ketone insoluble content is 50% by weight or less. It is preferable that the complex viscosity ([η] 60°C) at 60°C is 15,000 [Pa·s] or less.

In the acrylic rubber of the present invention, it is preferable that the value when the amount of methyl ethyl ketone insoluble content is measured at 20 points is all within the range of (average value ± 5)% by weight.

In the acrylic rubber of the present invention, the ratio of the complex viscosity at 100°C ([η]100°C) to the complex viscosity at 60°C ([η]60°C) ([η]100°C/[η]60 °C) is preferably 0.8 or more.

In the acrylic rubber of the present invention, it is preferable that the specific gravity is 0.8 or more.

In the acrylic rubber of the present invention, it is preferably sheet-like or veil-like.

Further, the acrylic rubber of the present invention is preferably obtained by emulsion polymerization using a phosphoric acid ester salt or a sulfuric acid ester salt as an emulsifier. It is preferably solidified and dried. Further, the acrylic rubber of the present invention is preferably melt-kneaded and dried after solidification, wherein the melt-kneaded and dried are performed in a state substantially free of moisture, the melt-kneaded and It is preferable that drying is performed under reduced pressure. Furthermore, it is preferable that the acrylic rubber of the present invention is cooled at a cooling rate of 40°C/hr or higher after the above melt kneading and drying.

In the acrylic rubber of the present invention, it is preferable that the ratio of the particle size in the range of 710 μm to 6.7 mm is 50% by weight or more of hydrous crumb washed, dehydrated and dried.

According to the present invention, polymerization is initiated in the presence of an emulsion step of emulsifying an acrylic rubber monomer component containing (meth)acrylic acid ester as a main component with water and an emulsifier, and a redox catalyst containing an inorganic radical generator and a reducing agent An emulsion polymerization step of batchwise post-adding a chain transfer agent during polymerization to continue polymerization to obtain an emulsion polymerization solution, and a coagulation step of adding the obtained emulsion polymerization solution to a stirring coagulation solution and coagulating it to generate a hydrous crumb; A method for producing acrylic rubber comprising a washing step of washing the resulting hydrous crumb with warm water, a dehydration step of dewatering the washed hydrous crumb, and a drying step of drying the dehydrated hydrous crumb to less than 1% by weight is provided.

In the production method of the acrylic rubber of the present invention, it is preferable to manufacture the above acrylic rubber.

In the method for producing acrylic rubber of the present invention, it is preferable to carry out emulsion polymerization using a phosphoric acid ester salt or a sulfuric acid ester salt as an emulsifier.

In the method for producing acrylic rubber of the present invention, it is preferable to coagulate the polymerization solution produced in the emulsion polymerization step by using an alkali metal salt or a periodic table Group 2 metal salt as a coagulant and then dry it.

In the acrylic rubber production method of the present invention, it is preferable to coagulate the polymerization solution produced in the emulsion polymerization step by adding it to an aqueous solution containing a coagulant containing an alkali metal salt or periodic table Group 2 metal salt and stirring it.

In the production method of the acrylic rubber of the present invention, it is preferable that the polymerization solution produced in the emulsion polymerization step is brought into contact with a coagulant to solidify, followed by melt kneading and drying.

In the acrylic rubber production method of the present invention, it is preferable that the above melt kneading and drying are performed in a state in which water is not substantially contained.

In the acrylic rubber production method of the present invention, it is preferable that the above melt kneading and drying are performed under reduced pressure.

In the acrylic rubber production method of the present invention, it is preferable that the above melt kneading and drying are performed with a screw-type twin-screw extrusion dryer.

In the acrylic rubber production method of the present invention, it is preferable that the maximum torque of the screw-type twin-screw extrusion dryer at the time of melt kneading and drying is 20 N·m or more.

In the acrylic rubber production method of the present invention, it is preferable to cool the acrylic rubber after melt kneading and drying at a cooling rate of 40°C/hr or higher.

In the acrylic rubber production method of the present invention, it is preferable that the coagulant concentration of the coagulant liquid is 1% by weight or more.

In the acrylic rubber production method of the present invention, it is preferable that the stirring number of the coagulating liquid being stirred is 100 rpm or more.

In the acrylic rubber production method of the present invention, it is preferable that the circumferential speed of the coagulating liquid being stirred is 1 m/s or more.

In the acrylic rubber production method of the present invention, it is preferable to post-add a reducing agent in the emulsion polymerization step.

In the acrylic rubber production method of the present invention, it is preferable to wash, dehydrate, and dry the hydrous crumb having a particle size in the range of 710 μm to 6.7 mm in a ratio of 50% by weight or more.

According to the present invention, a rubber composition comprising a rubber component containing the above acrylic rubber, a filler, and a crosslinking agent is further provided.

In the rubber composition of the present invention, it is preferable that the filler is a reinforcing filler. Further, in the rubber composition of the present invention, it is preferable that the filler is carbon black. Further, in the rubber composition of the present invention, it is preferable that the filler is a silica type.

In the rubber composition of the present invention, it is preferable that the crosslinking agent is an organic crosslinking agent. Further, in the rubber composition of the present invention, it is preferable that the crosslinking agent is a polyvalent compound. In addition, in the rubber composition of the present invention, it is preferable that the crosslinking agent is an ionic crosslinkable compound. Furthermore, in the rubber composition of the present invention, it is preferable that the crosslinking agent is an ionic crosslinkable organic compound. Furthermore, in the rubber composition of the present invention, it is preferable that the crosslinking agent is a polyvalent ion organic compound.

In the rubber composition of the present invention, the ion of the ion crosslinkable compound, ion crosslinkable organic compound or polyvalent ion organic compound as the crosslinking agent is at least one ion reactive group selected from the group consisting of an amino group, an epoxy group, a carboxyl group and a thiol group. it is desirable

In the rubber composition of the present invention, the crosslinking agent is preferably at least one polyvalent ionic compound selected from the group consisting of polyvalent amine compounds, polyvalent epoxy compounds, polyvalent carboxylic acid compounds and polyvalent thiol compounds.

In the rubber composition of the present invention, the content of the crosslinking agent is preferably in the range of 0.001 to 20 parts by weight based on 100 parts by weight of the rubber component.

The rubber composition of the present invention preferably further contains an anti-aging agent. In the rubber composition of the present invention, it is preferable that the anti-aging agent is an amine-based anti-aging agent.

According to the present invention, there is also provided a method for producing a rubber composition in which a crosslinking agent is mixed after mixing a rubber component containing the above acrylic rubber, a filler, and, if necessary, an antiaging agent.

According to the present invention, a crosslinked rubber product obtained by crosslinking the above rubber composition is further provided. In the crosslinked rubber product of the present invention, crosslinking of the rubber composition is preferably performed after molding. Further, in the crosslinked rubber product of the present invention, it is preferable that the crosslinking of the rubber composition is performed by primary crosslinking and secondary crosslinking.

According to the present invention, an acrylic rubber excellent in roll processability and highly excellent in strength characteristics and water resistance of a crosslinked product, an efficient production method thereof, a high-quality rubber composition containing the acrylic rubber, and a crosslinked rubber product crosslinked therefrom are provided. .

1 is a diagram schematically showing an example of an acrylic rubber production system used for production of acrylic rubber according to an embodiment of the present invention.
Figure 2 is a view showing the configuration of the screw type extruder of Figure 1.
FIG. 3 is a diagram showing the configuration of a transport type cooling device used as the cooling device of FIG. 1 .

The acrylic rubber of the present invention has a (meth)acrylic acid ester as a main component and a dimethylformamide-based solvent as a developing solvent. 1 million or more, the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn) (Mw/Mn) is 3.4 or more, the amount of ash is 0.4% by weight or less, and the total amount of sodium, magnesium, calcium, phosphorus and sulfur in the ash is It is characterized in that more than 80% by weight. Here, the "GPC-MALS method" is the following content. GPC (gel permeation chromatography) is a type of liquid chromatography that separates based on differences in molecular sizes. By combining this device with a multi-angle laser light scattering photometer (MALS) and a differential refractometer (RI), the light scattering intensity and refractive index difference of the molecular chain solution size-classified with the GPC device are measured according to the melting time, thereby determining the molecular weight of the solute. and its content are sequentially calculated, and finally the absolute molecular weight distribution and absolute average molecular weight value of the polymer material are obtained.

<Monomer component>

The acrylic rubber of the present invention is characterized by having a (meth)acrylic acid ester as a main component. Here, "main component" means that the content in the acrylic rubber is usually 50% by weight or more, preferably 60% by weight or more, more preferably means 70% by weight or more, particularly preferably 80% by weight or more. Meanwhile, in the present invention, "(meth)acrylic acid ester" is used as a generic term for esters of acrylic acid and/or methacrylic acid.

In the acrylic rubber of the present invention, those having a reactive group, preferably those having an ion reactive group, or those having at least one reactive group selected from the group consisting of a carboxyl group, an epoxy group and a chlorine atom have crosslinkability and permanent compression resistance. It is suitable because it has excellent deformation characteristics. The ion-reactive group is not particularly limited as long as it is a functional group that reacts with an ion, but is preferably at least one functional group selected from the group consisting of a carboxyl group, an epoxy group and a chlorine atom, more preferably an epoxy group and a carboxyl group, and particularly preferably a carboxyl group. . The acrylic rubber having such a reactive group may be one in which a reactive group is introduced into the acrylic rubber by a post-reaction, but an acrylic rubber obtained by copolymerizing a reactive group-containing monomer is preferable.

Preferred monomer components of the acrylic rubber of the present invention are at least one (meth)acrylic acid ester selected from the group consisting of (meth)acrylic acid alkyl esters and (meth)acrylic acid alkoxyalkyl esters, a reactive group-containing monomer, and, if necessary, It consists of other monomers which can be copolymerized.

The (meth)acrylic acid alkyl ester is not particularly limited, but is usually a (meth)acrylic acid alkyl ester having an alkyl group of 1 to 12 carbon atoms, preferably a (meth)acrylic acid alkyl ester having an alkyl group of 1 to 8 carbon atoms. Preferably, a (meth)acrylic acid alkyl ester having an alkyl group having 2 to 6 carbon atoms is used.

Specific examples of (meth)acrylic acid alkyl esters include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, (meth)acrylate. isobutyl acrylate, n-hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and cyclohexyl (meth)acrylate; among these, ethyl (meth)acrylate and n-butyl (meth)acrylate are preferred. And ethyl acrylate and n-butyl acrylate are more preferable.

The (meth)acrylic acid alkoxyalkyl ester is not particularly limited, but is usually a (meth)acrylic acid alkoxyalkyl ester having an alkoxyalkyl group having 2 to 12 carbon atoms, preferably a (meth)acrylic acid alkoxy having an alkoxyalkyl group having 2 to 8 carbon atoms. An alkyl ester, more preferably a (meth)acrylic acid alkoxyalkyl ester having an alkoxyalkyl group having 2 to 6 carbon atoms is used.

Specific examples of the (meth)acrylic acid alkoxyalkyl ester include methoxymethyl (meth)acrylate, methoxyethyl (meth)acrylate, methoxypropyl (meth)acrylate, methoxybutyl (meth)acrylate, and (meth)acrylic acid Toxymethyl, ethoxyethyl (meth)acrylate, propoxyethyl (meth)acrylate, butoxyethyl (meth)acrylate, and the like. Among these, methoxyethyl (meth)acrylate, ethoxyethyl (meth)acrylate, etc. are preferable, and methoxyethyl acrylate and ethoxyethyl acrylate are more preferable.

At least one (meth)acrylic acid ester selected from the group consisting of these (meth)acrylic acid alkyl esters and (meth)acrylic acid alkoxyalkyl esters is used alone or in combination of two or more, respectively, in all monomer components Their ratio is usually 50 to 99.99% by weight, preferably 62 to 99.95% by weight, more preferably 74 to 99.9% by weight, particularly preferably 80 to 99.5% by weight, and most preferably 87 to 99% by weight. In the range of , the weather resistance, heat resistance and oil resistance of acrylic rubber are highly excellent and suitable.

The reactive group-containing monomer is not particularly limited as long as it is a monomer having a functional group involved in reaction with a crosslinking agent and the like, and is appropriately selected depending on the purpose of use. Preferably, a monomer having an ion-reactive group involved in an ionic reaction or a carboxyl group, an epoxy group, and chlorine When a monomer having at least one reactive group selected from the group consisting of atoms, more preferably a monomer having a carboxyl group or an epoxy group, and more preferably a monomer having a carboxyl group, short-time crosslinking properties and compression set resistance of the crosslinked product; It is suitable because it can highly improve water resistance.

Although there is no particular limitation as a monomer which has a carboxyl group, Ethylenically unsaturated carboxylic acid can be used suitably. Examples of the ethylenically unsaturated carboxylic acids include ethylenically unsaturated monocarboxylic acids, ethylenically unsaturated dicarboxylic acids, and ethylenically unsaturated dicarboxylic acid monoesters. Among these, particularly ethylenically unsaturated Dicarboxylic acid monoesters are preferable because they can further enhance compression set resistance when acrylic rubber is used as a rubber cross-linked product.

The ethylenically unsaturated monocarboxylic acid is not particularly limited, but ethylenically unsaturated monocarboxylic acids having 3 to 12 carbon atoms are preferable, and examples thereof include acrylic acid, methacrylic acid, α-ethylacrylic acid, crotonic acid, and cinnamic acid. etc. can be mentioned.

As the ethylenically unsaturated dicarboxylic acid, there is no particular limitation, but an ethylenically unsaturated dicarboxylic acid having 4 to 12 carbon atoms is preferable. For example, fumaric acid, butenedioic acid such as maleic acid, itaconic acid, and citraconic acid etc. can be mentioned. On the other hand, ethylenically unsaturated dicarboxylic acids include those existing as an anhydride.

The ethylenically unsaturated dicarboxylic acid monoester is not particularly limited, but is usually an ethylenically unsaturated dicarboxylic acid having 4 to 12 carbon atoms and an alkyl monoester having 1 to 12 carbon atoms, preferably ethylene having 4 to 6 carbon atoms. C2-C8 alkyl monoesters with sexually unsaturated dicarboxylic acids, and more preferably C2-C6 alkyl monoesters of C4 butenedioic acid.

Specific examples of the ethylenically unsaturated dicarboxylic acid monoester include monomethyl fumarate, monoethyl fumarate, monon-butyl fumarate, monomethyl maleate, monoethyl maleate, monon-butyl maleate, and monocyclopentyl fumarate. butenedioic acid monoalkyl esters such as monocyclohexyl fumarate, monocyclohexenyl fumarate, monocyclopentyl maleate, and monocyclohexyl maleate; itaconic acid monoalkyl esters such as monomethyl itaconate, monoethyl itaconate, mono-n-butyl itaconate, and monocyclohexyl itaconate; These etc. are mentioned, Among these, mono-n-butyl fumarate and mono-n-butyl maleate are preferable, and mono-n-butyl fumarate is especially preferable.

Examples of the monomer having an epoxy group include epoxy group-containing (meth)acrylic acid esters such as glycidyl (meth)acrylate; epoxy group-containing vinyl ethers such as allyl glycidyl ether and vinyl glycidyl ether; etc. can be mentioned.

The monomer having a chlorine atom is not particularly limited, and examples thereof include unsaturated alcohol esters of chlorine atom-containing saturated carboxylic acids, (meth)acrylic acid chloroalkyl esters, (meth)acrylic acid chloroacyloxyalkyl esters, (meth)acrylic acid chloroacyloxyalkyl esters, ) acrylic acid (chloroacetylcarbamoyloxy)alkyl esters, chlorine atom-containing unsaturated ethers, chlorine atom-containing unsaturated ketones, chloromethyl group-containing aromatic vinyl compounds, chlorine atom-containing unsaturated amides, chloroacetyl group-containing unsaturated monomers, and the like.

Specific examples of the unsaturated alcohol ester of a chlorine atom-containing saturated carboxylic acid include vinyl chloroacetate, vinyl 2-chloropropionate, and allyl chloroacetate. Specific examples of the (meth)acrylic acid chloroalkyl ester include chloromethyl (meth)acrylate, 1-chloroethyl (meth)acrylate, 2-chloroethyl (meth)acrylate, 1,2-dichloroethyl (meth)acrylate, ( 2-chloropropyl (meth)acrylate, 3-chloropropyl (meth)acrylate, and 2,3-dichloropropyl (meth)acrylate. Specific examples of (meth)acrylic acid chloroacyloxyalkyl esters include (meth)acrylic acid 2-(chloroacetoxy)ethyl, (meth)acrylic acid 2-(chloroacetoxy)propyl, (meth)acrylic acid 3-(chloroacetic acid). Toxy)propyl, (meth)acrylic acid 3-(hydroxychloroacetoxy)propyl, etc. are mentioned. Examples of the (meth)acrylic acid (chloroacetylcarbamoyloxy)alkyl ester include 2-(chloroacetylcarbamoyloxy)ethyl (meth)acrylic acid and 3-(chloroacetylcarbamoyloxy)ethyl (meth)acrylic acid. ) profile, etc. Specific examples of the chlorine atom-containing unsaturated ether include chloromethyl vinyl ether, 2-chloroethyl vinyl ether, 3-chloropropyl vinyl ether, 2-chloroethyl allyl ether, and 3-chloropropyl allyl ether. Specific examples of the chlorine atom-containing unsaturated ketone include 2-chloroethyl vinyl ketone, 3-chloropropyl vinyl ketone, and 2-chloroethyl allyl ketone. Specific examples of the chloromethyl group-containing aromatic vinyl compound include p-chloromethyl styrene, m-chloromethyl styrene, o-chloromethyl styrene, and p-chloromethyl-α-methyl styrene. Specific examples of the chlorine atom-containing unsaturated amide include N-chloromethyl (meth)acrylamide. Further, specific examples of the chloroacetyl group-containing unsaturated monomer include 3-(hydroxychloroacetoxy)propyl allyl ether and p-vinylbenzylchloroacetic acid ester.

These reactive group-containing monomers are used individually or in combination of two or more, and the ratio in all monomer components is usually 0.01 to 10% by weight, preferably 0.05 to 8% by weight, more preferably 0.1 to 6% by weight. , particularly preferably in the range of 0.5 to 5% by weight, most preferably in the range of 1 to 3% by weight.

There is no particular limitation as long as the monomers other than the above (abbreviated as "other monomers" in the present invention) that can be used together with the above monomers as needed are copolymerizable with the above monomers. For example, styrene, α- aromatic vinyls such as methyl styrene and divinylbenzene; ethylenically unsaturated nitriles such as acrylonitrile and methacrylonitrile; acrylamide-based monomers such as acrylamide and methacrylamide; Olefin type monomers, such as ethylene, propylene, vinyl acetate, ethyl vinyl ether, and butyl vinyl ether, etc. are mentioned.

These other monomers are used individually or in combination of two or more, and the ratio in all monomer components is usually 0 to 40% by weight, preferably 0 to 30% by weight, more preferably 0 to 20% by weight. , particularly preferably in the range of 0 to 15% by weight, most preferably in the range of 0 to 10% by weight.

<Acrylic Rubber>

The acrylic rubber of the present invention has a (meth)acrylic acid ester as a main component, preferably at least one (meth)acrylic acid ester selected from the group consisting of (meth)acrylic acid alkyl esters and (meth)acrylic acid alkoxyalkyl esters; It consists of a bonding unit from a reactive group-containing monomer and other monomers included as necessary, and each ratio in the acrylic rubber is at least selected from the group consisting of (meth)acrylic acid alkyl esters and (meth)acrylic acid alkoxyalkyl esters. The bonding unit derived from one type of (meth)acrylic acid ester is usually 50 to 99.99% by weight, preferably 62 to 99.95% by weight, more preferably 74 to 99.9% by weight, particularly preferably 80 to 99.5% by weight, Most preferably, it is in the range of 87 to 99% by weight, and the bonding unit derived from the reactive group-containing monomer is usually 0.01 to 10% by weight, preferably 0.05 to 8% by weight, more preferably 0.1 to 6% by weight, especially It is preferably in the range of 0.5 to 5% by weight, most preferably 1 to 3% by weight, and the bonding unit derived from other monomers is usually 0 to 40% by weight, preferably 0 to 30% by weight, more preferably is in the range of 0 to 20% by weight, particularly preferably 0 to 15% by weight, most preferably 0 to 10% by weight. When the monomer composition of acrylic rubber is within this range, properties such as short-time crosslinking, compression set resistance, weather resistance, heat resistance, and oil resistance are highly balanced and suitable.

The reactive group content of the acrylic rubber of the present invention is not particularly limited and may be appropriately selected depending on the purpose of use, but is usually 0.001 to 5% by weight, preferably 0.01 to 3% by weight, more preferably 0.01 to 3% by weight in terms of the weight ratio of the reactive group itself. When it is in the range of 0.05 to 1% by weight, particularly preferably 0.1 to 0.5% by weight, workability or crosslinkability, and strength characteristics when crosslinked, compression set resistance, oil resistance, cold resistance, water resistance, etc. It is suitable because the characteristics of are highly balanced.

The weight average molecular weight (Mw) of the acrylic rubber of the present invention is 1,000,000 or more, preferably 1,200,000 or more, more preferably 1,500,000, as an absolute molecular weight measured by the GPC-MALS method using dimethylformamide as a developing solvent. More than that. If the weight average molecular weight (Mw) of the acrylic rubber of the present invention is excessively small, strength characteristics and compression set resistance are deteriorated, which is not preferable. The weight average molecular weight (Mw) of the acrylic rubber of the present invention is usually 1 million to 3.5 million, preferably 1.2 million to 3 million, more preferably 1.3 million to 3 million, and particularly preferably 1.5 million to 2.5 million. However, most preferably, when the range is 1.9 million to 2.1 million, the roll processability, strength characteristics, and compression set resistance of acrylic rubber are highly balanced and suitable.

The number average molecular weight (Mn) of the acrylic rubber of the present invention is not particularly limited and may be appropriately selected depending on the purpose of use, but is an absolute molecular weight measured by the GPC-MALS method using a dimethylformamide solvent as a developing solvent, and is usually 10 Rolls of acrylic rubber in the range of 10,000 to 500,000, preferably 200,000 to 480,000, more preferably 250,000 to 450,000, particularly preferably 300,000 to 400,000, and most preferably 350,000 to 400,000 Workability, strength characteristics, and compression set resistance are highly balanced and suitable.

The z-average molecular weight (Mz) of the acrylic rubber of the present invention is not particularly limited and may be appropriately selected depending on the purpose of use, but the high molecular weight region measured by the GPC-MALS method using a dimethylformamide solvent as a developing solvent is emphasized. When the absolute molecular weight is in the range of usually 1.5 million to 6 million, preferably 2 million to 5 million, more preferably 2.5 million to 4.5 million, and particularly preferably 3 million to 4 million, acrylic rubber roll processability and strength characteristics , and compression set resistance are highly balanced and suitable.

The ratio (Mw/Mn) of the weight average molecular weight (Mw) and number average molecular weight (Mn) of the acrylic rubber of the present invention is an absolute molecular weight distribution measured by the GPC-MALS method using a dimethylformamide solvent as a developing solvent, It is 3.4 or more, preferably 3.5 or more, more preferably 3.6 or more, and particularly preferably 3.7 or more. When the ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of the acrylic rubber of the present invention is excessively small, roll workability is deteriorated, which is not preferable. The ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of the acrylic rubber of the present invention is usually 3.7 to 6.5, preferably 3.8 to 6.2, more preferably 4 to 6, Particularly preferably in the range of 4.5 to 5.7, most preferably 4.7 to 5.5, it is suitable because roll workability, crosslinked strength characteristics and compression set resistance can be highly balanced.

The ratio (Mz/Mw) of the z-average molecular weight (Mz) and the weight-average molecular weight (Mw) of the acrylic rubber of the present invention may be appropriately selected depending on the purpose of use without particular limitation, but using a dimethylformamide-based solvent as a developing solvent Absolute molecular weight distribution with emphasis on the polymer region measured by the GPC-MALS method, usually 1.3 to 3, preferably 1.4 to 2.7, more preferably 1.5 to 2.5, particularly preferably 1.8 to 2, most preferably 1.8 In the range of ~ 1.95, it is suitable because the workability and strength characteristics of acrylic rubber are highly balanced and the change in physical properties during storage can be alleviated.

The dimethylformamide-based solvent used as the measuring solvent in the GPC-MALS method is not particularly limited as long as it has dimethylformamide as a main component, and for example, 100% dimethylformamide or dimethylformamide in a dimethylformamide-based solvent is used. A ratio of 90% by weight, preferably 95% by weight, more preferably 97% by weight or more is used. The compound added to dimethylformamide is not particularly limited, but in the present invention, a solution in which lithium chloride is added to dimethylformamide at a concentration of 0.05 mol/L and 37% concentrated hydrochloric acid at a concentration of 0.01%, respectively, is suitable. .

The ash content of the acrylic rubber of the present invention is 0.4% by weight or less, preferably 0.3% by weight or less, more preferably 0.2% by weight or less, still more preferably 0.18% by weight or less, particularly preferably 0.15% by weight or less, Most preferably, it is 0.13% by weight or less, and when it is in this range, the water resistance, strength characteristics and processability of acrylic rubber are highly balanced and suitable.

The lower limit of the ash content of the acrylic rubber of the present invention is not particularly limited and may be appropriately selected depending on the purpose of use, but is usually 0.0001% by weight or more, preferably 0.0005% by weight or more, more preferably 0.001% by weight or more, still more preferably. When it is preferably 0.003% by weight or more, particularly preferably 0.005% by weight or more, and most preferably 0.01% by weight or more, it is suitable because the metal adhesion of rubber is reduced and workability is excellent.

The amount of ash when the acrylic rubber of the present invention is highly balanced in water resistance, strength characteristics, workability and workability is usually 0.0001 to 0.4% by weight, preferably 0.0005 to 0.3% by weight, more preferably 0.001 to 0.2% by weight. , more preferably 0.003 to 0.18% by weight, particularly preferably 0.005 to 0.15% by weight, most preferably 0.01 to 0.13% by weight.

The total amount of sodium, magnesium, calcium, phosphorus and sulfur in the ash of the acrylic rubber of the present invention is 80% by weight or more, preferably 83% by weight or more, more preferably 85% by weight or more, particularly preferably 87% by weight or more , most preferably 90% by weight or more, the water resistance of the acrylic rubber is highly improved and is suitable. In addition, when the total amount of sodium, magnesium, calcium, phosphorus and sulfur in the ash content of the acrylic rubber of the present invention is within this range, metal adhesion is reduced and workability is excellent, so it is suitable.

The total amount of magnesium and phosphorus in the ash of the acrylic rubber of the present invention is not particularly limited and may be appropriately selected depending on the purpose of use, but is usually 30% by weight or more, preferably 50% by weight or more, more preferably 70% by weight or more, When it is particularly preferably 80% by weight or more, and most preferably 90% by weight or more, the water resistance, strength characteristics and workability of acrylic rubber are highly balanced and suitable. In addition, when the total amount of magnesium and phosphorus in the ash content of the acrylic rubber of the present invention is within this range, metal adhesion is reduced and workability is excellent, which is suitable.

The amount of magnesium in the ash of the acrylic rubber of the present invention is not particularly limited and is appropriately selected depending on the purpose of use, but is usually 10% by weight or more, preferably 15 to 60% by weight, more preferably 20 to 50% by weight, particularly It is preferably in the range of 25 to 45% by weight, most preferably 30 to 40% by weight.

The amount of phosphorus in the ash content of the acrylic rubber of the present invention is not particularly limited and is appropriately selected depending on the purpose of use, but is usually 10% by weight or more, preferably 20 to 90% by weight, more preferably 30 to 80% by weight, particularly preferably Preferably it is in the range of 40 to 70% by weight, most preferably 50 to 60% by weight.

The ratio of magnesium to phosphorus in the ash content of the acrylic rubber of the present invention ([Mg]/[P]) is not particularly limited and may be appropriately selected depending on the purpose of use, but in terms of weight ratio, it is usually 0.4 to 2.5, preferably 0.45 to 1.2. , more preferably 0.45 to 1, particularly preferably 0.5 to 0.8, and most preferably 0.55 to 0.7, the water resistance, strength characteristics and workability of acrylic rubber are highly balanced and suitable.

Here, the ash in the acrylic rubber is mainly derived from the emulsifier used when emulsifying the monomer components and performing emulsion polymerization and the coagulant used when coagulating the emulsion polymerization solution. , It is changed not only by the conditions of the emulsion polymerization process and the solidification process, but also by various conditions of each subsequent process.

The acrylic rubber of the present invention, when an anionic emulsifier, a cationic emulsifier, or a nonionic emulsifier, preferably an anionic emulsifier, more preferably a phosphate ester salt or a sulfate ester salt is used as an emulsifier in the emulsion polymerization described later. , In addition to water resistance and strength characteristics, it is suitable for highly improving mold release and workability. The water resistance of acrylic rubber is uniquely correlated with the amount of ash in acrylic rubber and the total amount of sodium, magnesium, calcium, phosphorus and sulfur in the ash. It is suitable because it can balance more highly.

When a metal salt, preferably an alkali metal salt or a Group 2 metal salt of the periodic table is used as a coagulant described later, the acrylic rubber of the present invention can highly improve mold release properties and processability in addition to water resistance and strength properties, and is suitable. The water resistance of acrylic rubber is uniquely correlated with the amount of ash in acrylic rubber and the total amount of sodium, magnesium, calcium, phosphorus and sulfur in the ash. This is more highly balanced and suitable.

The glass transition temperature (Tg) of the acrylic rubber of the present invention may be appropriately selected depending on the purpose of use of the acrylic rubber, but when it is usually 20°C or less, preferably 10°C or less, and more preferably 0°C or less, workability and cold resistance are improved. excellent and good The lower limit of the glass transition temperature (Tg) of acrylic rubber is not particularly limited, but is usually -80°C or higher, preferably -60°C or higher, more preferably -40°C or higher. When the glass transition temperature is set to be equal to or higher than the above lower limit, oil resistance and heat resistance can be further improved, and when the glass transition temperature is set to be equal to or lower than the upper limit, workability, crosslinkability and cold resistance are further improved.

The complex viscosity ([η] 60°C) of the acrylic rubber of the present invention at 60°C is not particularly limited and may be appropriately selected depending on the purpose of use, but is usually 15,000 [Pa s] or less, preferably 1,000 to 10,000. Processability when in the range of [Pa s], more preferably 2,000 to 5,000 [Pa s], particularly preferably 2,500 to 4,000 [Pa s], and most preferably 2,500 to 3,000 [Pa s] , excellent in oil resistance and shape retention.

The complex viscosity ([η] 100°C) at 100°C of the acrylic rubber of the present invention is not particularly limited and may be appropriately selected depending on the purpose of use, but is usually 1,500 to 6,000 [Pa s], preferably 2,000 to 6,000 [Pa s]. Processability in the range of 5,000 [Pa s], more preferably 2,300 to 4,000 [Pa s], particularly preferably 2,500 to 3,500 [Pa s], and most preferably 2,500 to 3,000 [Pa s] , excellent in oil resistance and shape retention.

The ratio of the complex viscosity of the acrylic rubber of the present invention at 100°C ([η]100°C) to the complex viscosity at 60°C ([η]60°C) ([η]100°C/[η]60°C) is not particularly limited and may be appropriately selected depending on the purpose of use, but is usually 0.5 or more, preferably 0.6 or more, more preferably 0.7 or more, particularly preferably 0.8 or more, and most preferably 0.83 or more. The ratio of the complex viscosity of the acrylic rubber of the present invention at 100°C ([η]100°C) to the complex viscosity at 60°C ([η]60°C) ([η]100°C/[η]60°C) is also usually 0.5 to 0.99, preferably 0.6 to 0.98, more preferably 0.7 to 0.97, particularly preferably 0.8 to 0.96, and most preferably 0.85 to 0.95 when in the range of workability, oil resistance, and shape retention This is highly balanced and suitable.

The amount of insoluble methyl ethyl ketone in the acrylic rubber of the present invention is not particularly limited and may be appropriately selected depending on the purpose of use, but is usually 50% by weight or less, preferably 30% by weight or less, more preferably 15% by weight or less. , particularly preferably 10% by weight or less, most preferably 5% by weight or less, it is suitable because the workability during kneading by Banbury or the like is highly improved.

The value (variance amount) when the amount of methyl ethyl ketone insoluble content of the acrylic rubber of the present invention is arbitrarily measured at 20 points is not particularly limited, but all 20 points fall within the range of (average value ± 5)% by weight, preferably More specifically, when all 20 points are within the range of (average value ± 3) weight%, there is no processability deviation, and various physical properties of the rubber composition or crosslinked rubber product are stabilized and suitable. On the other hand, when the methyl ethyl ketone insoluble content of acrylic rubber is arbitrarily measured at 20 points, all 20 points fall within the range of the average value ± 5, (average value - 5) to (average value + 5) of % by weight It means that all 20 points of methyl ethyl ketone insoluble content measured are within the range. For example, when the average value of the measured methyl ethyl ketone insoluble content is 20% by weight, 20 This means that the measured values of all points are included.

When the acrylic rubber of the present invention is melt-kneaded and dried in a state in which water is almost removed (moisture content less than 1% by weight) with a screw-type twin-screw extrusion dryer for the water-containing crumb produced in the coagulation reaction, Banbury processability and strength characteristics are highly balanced and fit

The water content of the acrylic rubber of the present invention is not particularly limited and is appropriately selected depending on the purpose of use. When it is usually less than 1% by weight, preferably 0.8% by weight or less, and more preferably 0.6% by weight or less, the vulcanization properties of the acrylic rubber This is optimized, and properties such as heat resistance and water resistance in the form of strands are highly improved and are suitable.

The pH of the acrylic rubber of the present invention is not particularly limited and may be appropriately selected depending on the purpose of use, but is usually 6 or less, preferably 2 to 6, more preferably 2.5 to 5.5, and most preferably 3 to 5. When the storage stability of acrylic rubber is highly improved, it is suitable.

The Mooney viscosity (ML1+4, 100°C) of the acrylic rubber of the present invention is not particularly limited and may be appropriately selected depending on the purpose of use, but is usually 10 to 150, preferably 20 to 100, and more preferably 25 to 70. In the range of , the workability and strength characteristics of acrylic rubber are highly balanced and suitable.

The specific gravity of the acrylic rubber of the present invention is not particularly limited, but usually contains air when it is 0.7 or more, preferably 0.8 or more, more preferably 0.9 or more, particularly preferably 0.95 or more, and most preferably 1 or more. It is suitable because it has excellent storage stability. When the specific gravity of the acrylic rubber of the present invention is in the range of usually 0.7 to 1.6, preferably 0.8 to 1.5, more preferably 0.9 to 1.4, particularly preferably 0.95 to 1.3, and most preferably 1.0 to 1.2. Productivity, storage stability and stability of crosslinking properties of crosslinked products are highly balanced and suitable. When the specific gravity of the acrylic rubber is excessively small, it indicates that the amount of air in the acrylic rubber is large, and it greatly affects the storage stability including oxidative deterioration and the like, which is not preferable.

On the other hand, the specific gravity of the acrylic rubber of the present invention is obtained by dividing the mass by the capacity including voids, that is, by dividing the mass measured in air by the buoyancy, which is usually measured according to JIS K6268 Crosslinked Rubber - Method A of Density Measurement will be.

The acrylic rubber of the present invention is obtained by drying the hydrous crumb produced in the coagulation reaction with a screw-type twin screw extrusion dryer under reduced pressure, or by melting and kneading and drying under reduced pressure. It is suitable because it is particularly excellent and highly balanced.

The shape of the acrylic rubber of the present invention is not particularly limited and may be appropriately selected depending on the purpose of use, and may be, for example, powder, crumb, strand, sheet, or veil, but preferably sheet or When it is in the form of a veil, it has excellent workability and storage stability, so it is suitable.

The thickness of the acrylic rubber of the present invention in sheet form is not particularly limited and is appropriately selected depending on the purpose of use, but is usually 1 to 40 mm, preferably 2 to 35 mm, more preferably 3 to 30 mm, and most preferably More specifically, in the range of 5 to 25 mm, workability, storage stability, and productivity are highly balanced and suitable. The width of the sheet-like acrylic rubber of the present invention is appropriately selected depending on the purpose of use, and is particularly excellent in handling when it is in the range of usually 300 to 1200 mm, preferably 400 to 1000 mm, and more preferably 500 to 800 mm. It is good for you. The length of the sheet-like acrylic rubber sheet of the present invention is not particularly limited, but is particularly excellent in handling when it is in the range of usually 300 to 1200 mm, preferably 400 to 1000 mm, and more preferably 500 to 800 mm. suitable

The size of the veil-shaped acrylic rubber of the present invention is not particularly limited and is appropriately selected depending on the purpose of use, but the width is usually 100 to 800 mm, preferably 200 to 500 mm, and more preferably 250 to 450 mm. range, the length is usually 300 to 1,200 mm, preferably 400 to 1,000 mm, more preferably 500 to 800 mm, and the height (thickness) is usually 50 to 500 mm, preferably 100 to 300 mm, More preferably, it is suitable to exist in the range of 150-250 mm. In addition, the shape of the veil-shaped acrylic rubber of the present invention is not limited, and is appropriately selected according to the purpose of use of the acrylic rubber veil, but in many cases, a rectangular parallelepiped is suitable.

<Method for producing acrylic rubber>

The method for producing the acrylic rubber is not particularly limited. For example, after emulsifying an acrylic rubber monomer component containing (meth)acrylic acid ester as a main component with water and an emulsifier, redox consisting of an inorganic radical generator and a reducing agent An emulsion polymerization step in which polymerization is initiated in the presence of a catalyst, a chain transfer agent is added batchwise during the polymerization, and polymerization is continued to obtain an emulsion polymerization solution; Acrylic rubber comprising a coagulation process to generate, a washing process to wash the generated hydrous crumb with hot water, a dehydration process to dehydrate the washed hydrous crumb, and a drying process to dry the dehydrated hydrous crumb to less than 1% by weight. It can be easily manufactured by the manufacturing method.

(monomer component)

The monomer components containing (meth)acrylic acid ester as a main component used in the present invention are the same as the examples and preferred ranges of the monomer components previously described. The usage amount of the monomer component is also as described above, and in emulsion polymerization, each monomer may be appropriately selected so as to have the above composition of the acrylic rubber of the present invention.

(Emulsifier)

The emulsifier used in the present invention is not particularly limited, but examples thereof include anionic emulsifiers, cationic emulsifiers, and nonionic emulsifiers, preferably anionic emulsifiers.

The anionic emulsifier is not particularly limited, and examples thereof include fatty acid salts such as myristic acid, palmitic acid, oleic acid, and linolenic acid; Alkylbenzenesulfonic acid salts, such as sodium dodecylbenzenesulfonate; phosphoric acid ester salts such as sulfuric acid ester salts such as sodium lauryl sulfate and polyoxyalkylene alkyl ether phosphoric acid ester salts; Alkyl sulfosuccinate etc. are mentioned. Among these anionic emulsifiers, phosphoric acid ester salts and sulfuric acid ester salts are preferred, phosphoric acid ester salts are particularly preferred, and divalent phosphate ester salts are most preferred. It is suitable because it can be balanced. In addition, as these phosphoric acid ester salts or sulfuric acid ester salts, preferably alkali metal salts of phosphoric acid esters or sulfuric acid esters, more preferably sodium salts of phosphoric acid esters or sulfuric acid esters, water resistance, strength characteristics and mold release properties of acrylic rubber obtained and workability can be highly balanced, so it is suitable.

The divalent phosphate ester salt is not particularly limited as long as it can be used as an emulsifier in the emulsion polymerization reaction, but includes alkyloxypolyoxyalkylene phosphate ester salts, alkylphenyloxypolyoxyalkylene phosphate ester salts, etc. Among these, metal salts thereof are preferred, alkali metal salts thereof are more preferred, and sodium salts thereof are most preferred.

As said alkyloxy polyoxyalkylene phosphate ester salt, the alkyloxy polyoxyethylene phosphate ester salt, the alkyloxy polyoxypropylene phosphate ester salt, etc. are mentioned, for example, Among these, the alkyloxy polyoxyethylene phosphate ester Salt is preferred.

Specific examples of the alkyloxypolyoxyethylene phosphate ester salt include octyloxydioxyethylene phosphate ester, octyloxytrioxyethylene phosphate ester, octyloxytetraoxyethylene phosphate ester, decyloxytetraoxyethylene phosphate ester, dodecyloxytetraoxy Ethylene Phosphate, Tridecyloxytetraoxyethylene Phosphate, Tetradecyloxytetraoxyethylene Phosphate, Hexadecyloxytetraoxyethylene Phosphate, Octadecyloxytetraoxyethylene Phosphate, Octyloxypentaoxyethylene Phosphate, Decyloxy Pentaoxyethylene Phosphate, Dodecyloxypentaoxyethylene Phosphate, Tridecyloxypentaoxyethylene Phosphate, Tetradecyloxypentaoxyethylene Phosphate, Hexadecyloxypentaoxyethylene Phosphate, Octadecyloxypentaoxyethylene Phosphate , octyloxyhexaoxyethylene phosphate ester, decyloxyhexaoxyethylene phosphate ester, dodecyloxyhexaoxyethylene phosphate ester, tridecyloxyhexaoxyethylene phosphate ester, tetradecyloxyhexaoxyethylene phosphate ester, hexadecyloxyhexaoxyethylene Phosphate ester, octadecyloxyhexaoxyethylene phosphate ester, octyloxyoctaoxyethylene phosphate ester, decyloxyoctaoxyethylene phosphate ester, dodecyloxyoctaoxyethylene phosphate ester, tridecyloxyoctaoxyethylene phosphate ester, tetradecyloxyocta and metal salts such as oxyethylene phosphate ester, hexadecyloxyoctaoxyethylene phosphate ester, and octadecyloxyoctaoxyethylene phosphate ester. Among these, alkali metal salts thereof, particularly sodium salts, are suitable.

Specific examples of the alkyloxypolyoxypropylene phosphate ester salt include octyloxydioxypropylene phosphate ester, octyloxytrioxypropylene phosphate ester, octyloxytetraoxypropylene phosphate ester, decyloxytetraoxypropylene phosphate ester, dodecyloxytetraoxy Propylene phosphate ester, tridecyloxytetraoxypropylene phosphate ester, tetradecyloxytetraoxypropylene phosphate ester, hexadecyloxytetraoxypropylene phosphate ester, octadecyloxytetraoxypropylene phosphate ester, octyloxypentaoxypropylene phosphate ester, decyloxy Pentaoxypropylene Phosphate, Dodecyloxypentaoxypropylene Phosphate, Tridecyloxypentaoxypropylene Phosphate, Tetradecyloxypentaoxypropylene Phosphate, Hexadecyloxypentaoxypropylene Phosphate, Octadecyloxypentaoxypropylene Phosphate , octyloxyhexaoxypropylene phosphate ester, decyloxyhexaoxypropylene phosphate ester, dodecyloxyhexaoxypropylene phosphate ester, tridecyloxyhexaoxypropylene phosphate ester, tetradecyloxyhexaoxypropylene phosphate ester, hexadecyloxyhexaoxypropylene Phosphate ester, octadecyloxyhexaoxypropylene phosphate ester, octyloxyoctaoxypropylene phosphate ester, decyloxyoctaoxypropylene phosphate ester, dodecyloxyoctaoxypropylene phosphate ester, tridecyloxyoctaoxypropylene phosphate ester, tetradecyloxyocta oxypropylene phosphate esters, hexadecyloxyoctaoxypropylene phosphate esters, octadecyloxyoctaoxypropylene phosphate esters, and metal salts thereof; among these, alkali metal salts thereof, particularly sodium salts, are suitable.

Specific examples of the alkylphenyloxypolyoxyalkylene phosphate ester salt include an alkylphenyloxypolyoxyethylene phosphate ester salt, an alkylphenyloxypolyoxypropylene phosphate ester salt, and the like, and among these, an alkylphenyloxypolyoxyethylene phosphate salt Ester salts are preferred.

Specific examples of the alkylphenyloxypolyoxyethylene phosphate ester salt include methylphenyloxytetraoxyethylene phosphate ester, ethylphenyloxytetraoxyethylene phosphate ester, butylphenyloxytetraoxyethylene phosphate ester, hexylphenyloxytetraoxyethylene phosphate ester, and nonyl. Phenyloxytetraoxyethylene phosphate ester, dodecylphenyloxytetraoxyethylene phosphate ester, octadecyloxytetraoxyethylene phosphate ester, methylphenyloxypentaoxyethylene phosphate ester, ethylphenyloxypentaoxyethylene phosphate ester, butylphenyloxypentaoxyethylene Phosphate ester, hexylphenyloxypentaoxyethylene phosphate ester, nonylphenyloxypentaoxyethylene phosphate ester, dodecylphenyloxypentaoxyethylene phosphate ester, methylphenyloxyhexaoxyethylene phosphate ester, ethylphenyloxyhexaoxyethylene phosphate ester, butylphenyl Oxyhexaoxyethylene Phosphate, Hexylphenyloxyhexaoxyethylene Phosphate, Nonylphenyloxyhexaoxyethylene Phosphate, Dodecylphenyloxyhexaoxyethylene Phosphate, Methylphenyloxyhexaoxyethylene Phosphate, Ethylphenyloxyoctaoxyethylene Phosphate metal salts such as esters, butylphenyloxyoctaoxyethylene phosphate esters, hexylphenyloxyoctaoxyethylene phosphate esters, nonylphenyloxyoctaoxyethylene phosphate esters, and dodecylphenyloxyoctaoxyethylene phosphate esters; Alkali metal salts, especially sodium salts, are suitable.

Specific examples of the alkylphenyloxypolyoxypropylene phosphate ester salt include methylphenyloxytetraoxypropylene phosphate ester, ethylphenyloxytetraoxypropylene phosphate ester, butylphenyloxytetraoxypropylene phosphate ester, hexylphenyloxytetraoxypropylene phosphate ester, and nonyl. Phenyloxytetraoxypropylene Phosphate, Dodecylphenyloxytetraoxypropylene Phosphate, Methylphenyloxypentaoxypropylene Phosphate, Ethylphenyloxypentaoxypropylene Phosphate, Butylphenyloxypentaoxypropylene Phosphate, Hexylphenyloxypentaoxypropylene Phosphate ester, nonylphenyloxypentaoxypropylene phosphate ester, dodecylphenyloxypentaoxypropylene phosphate ester, methylphenyloxyhexaoxypropylene phosphate ester, ethylphenyloxyhexaoxypropylene phosphate ester, butylphenyloxyhexaoxypropylene phosphate ester, hexylphenyl Oxyhexaoxypropylene Phosphate, Nonylphenyloxyhexaoxypropylene Phosphate, Dodecylphenyloxyhexaoxypropylene Phosphate, Methylphenyloxyoctaoxypropylene Phosphate, Ethylphenyloxyoctaoxypropylene Phosphate, Butylphenyloxyoctaoxypropylene Phosphate metal salts such as ester, hexylphenyloxyoctaoxypropylene phosphate ester, nonylphenyloxyoctaoxypropylene phosphate ester, and dodecylphenyloxyoctaoxypropylene phosphate ester; among these, alkali metal salts thereof, particularly sodium salts, are suitable. .

As the phosphoric acid ester salt, a monovalent phosphoric acid ester salt such as di(alkyloxypolyoxyalkylene) phosphoric acid ester sodium salt can be used alone or in combination with a divalent phosphoric acid ester salt.

Examples of the sulfate ester salt include sodium lauryl sulfate, potassium lauryl sulfate, ammonium lauryl sulfate, sodium myristyl sulfate, sodium polyoxyethylene alkyl sulfate, and sodium polyoxyethylene alkyl aryl sulfate. It is sodium uryl sulfate.

Examples of the cationic emulsifier include alkyltrimethylammonium chloride, dialkylammonium chloride, and benzylammonium chloride.

Examples of the nonionic emulsifier include polyoxyalkylene fatty acid esters such as polyoxyethylene stearate; polyoxyalkylene alkyl ethers such as polyoxyethylene dodecyl ether; polyoxyalkylene alkylphenol ethers such as polyoxyethylene nonylphenyl ether; Polyoxyethylene sorbitan alkyl ester etc. are mentioned, Polyoxyalkylene alkyl ether and polyoxyalkylene alkyl phenol ether are preferable, and polyoxyethylene alkyl ether and polyoxyethylene alkyl phenol ether are more preferable.

These emulsifiers can be used individually or in combination of two or more, and the amount used is usually 0.01 to 10 parts by weight, preferably 0.1 to 5 parts by weight, more preferably 0.1 to 5 parts by weight, based on 100 parts by weight of the monomer component. is in the range of 1 to 3 parts by weight.

The mixing method (mixing method) of the monomer component, water, and emulsifier may follow a conventional method, and examples thereof include a method of stirring the monomer, emulsifier, and water using an agitator such as a homogenizer or a disk turbine. can The amount of water used is usually 1 to 1000 parts by weight, preferably 5 to 500 parts by weight, more preferably 4 to 300 parts by weight, particularly preferably 3 to 150 parts by weight, most preferably 3 to 150 parts by weight, based on 100 parts by weight of the monomer components. Preferably it is in the range of 20 to 80 parts by weight.

(inorganic radical generator)

As the polymerization catalyst used in the present invention, a redox catalyst composed of an inorganic radical generating agent and a reducing agent is used. In particular, the use of an inorganic radical generating agent is suitable because the processability of acrylic rubber produced in a roll or the like can be improved to a high degree.

The inorganic radical generating agent is not particularly limited as long as it is commonly used in emulsion polymerization, and examples thereof include persulfates such as sodium persulfate, potassium persulfate and ammonium persulfate, hydrogen peroxide, and the like. Among these, persulfates are Preferably, potassium persulfate and ammonium persulfate are more preferable, and potassium persulfate is particularly preferable.

These inorganic radical generators can be used individually or in combination of two or more types, and the amount used is usually 0.0001 to 5 parts by weight, preferably 0.0005 to 1 part by weight, more preferably 0.0005 to 1 part by weight based on 100 parts by weight of the monomer component. It is preferably in the range of 0.001 to 0.25 parts by weight, particularly preferably in the range of 0.01 to 0.21 parts by weight, and most preferably in the range of 0.1 to 0.2 parts by weight.

(reducing agent)

The reducing agent used in the present invention is not particularly limited as long as it is usually used in emulsion polymerization, but preferably at least two reducing agents are used, and it is preferable to combine a metal ion compound in a reduced state with other reducing agents. It is suitable because the Banbury workability, roll workability and strength characteristics of the obtained acrylic rubber can be more highly balanced.

Examples of the reduced metal ion compound include, but are not particularly limited to, ferrous sulfate, sodium hexamethylenediamine tetraacetate, cuprous naphthenate, and the like, and among these, ferrous sulfate is preferred. do. These metal ion compounds in a reduced state can be used individually or in combination of two or more, and the amount used is usually 0.000001 to 0.01 part by weight, preferably 0.00001 to 0.001, based on 100 parts by weight of the monomer component. Part by weight, more preferably in the range of 0.00005 to 0.0005 part by weight.

The reducing agent other than the metal ion compound in a reduced state used in the present invention is not particularly limited, and examples thereof include ascorbic acid or salts thereof such as ascorbic acid, sodium ascorbate, and potassium ascorbate; Erythorbic acid or its salt, such as erythorbic acid, sodium erythorbate, and potassium erythorbate; sulfinates such as sodium hydroxymethane sulfinate; sulfites of sodium sulfite, potassium sulfite, sodium bisulfite, aldehyde sodium bisulfite, potassium bisulfite; pyrosulfite such as sodium pyrosulfite, potassium pyrosulfite, sodium hydrogen bisulfite, and potassium hydrogen pyrosulfite; thiosulfates such as sodium thiosulfate and potassium thiosulfate; phosphorous acid, sodium phosphite, potassium phosphite, sodium phosphite, phosphorous acid of phosphorous acid or potassium hydrogen phosphite, or a salt thereof; pyrophosphorous acid or salts thereof such as pyrophosphorous acid, sodium pyrophosphite, potassium pyrophosphite, sodium pyrophosphite, sodium hydrogen pyrophosphite, and potassium hydrogen pyrophosphite; Sodium formaldehyde sulfoxylate etc. are mentioned. Among these, ascorbic acid or a salt thereof, sodium formaldehyde sulfoxylate and the like are preferable, and ascorbic acid or a salt thereof is particularly preferable.

Reducing agents other than these metal ion compounds in a reduced state can be used individually or in combination of two or more, and the amount used is usually 0.001 to 1 part by weight, preferably 0.001 to 1 part by weight, based on 100 parts by weight of the monomer component. 0.005 to 0.5 parts by weight, more preferably 0.01 to 0.1 parts by weight.

A preferred combination of a metal ion compound in a reduced state and another reducing agent is a combination of ferrous sulfate and ascorbic acid or a salt thereof and/or sodium formaldehyde sulfoxylate, more preferably ferrous sulfate and ascorb It is an acid or a combination of its salts. The amount of ferrous sulfate used at this time is usually in the range of 0.000001 to 0.01 parts by weight, preferably 0.00001 to 0.001 parts by weight, more preferably 0.00005 to 0.0005 parts by weight, based on 100 parts by weight of the monomer components, and ascorbic acid or The amount of the salt and/or sodium formaldehyde sulfoxylate used is usually 0.001 to 1 part by weight, preferably 0.005 to 0.5 part by weight, more preferably 0.01 to 0.1 part by weight, based on 100 parts by weight of both components. .

The amount of water used in the emulsion polymerization reaction may be the amount used in emulsifying the monomer components, but is usually 10 to 1000 parts by weight, preferably 50 to 500 parts by weight, based on 100 parts by weight of the monomer components used for polymerization. More preferably, it is adjusted to be in the range of 80 to 400 parts by weight, most preferably 100 to 300 parts by weight.

The method of the emulsion polymerization reaction may be according to a conventional method, and any of a batch method, a semi-batch method, and a continuous method may be used. The polymerization temperature and polymerization time are not particularly limited and can be appropriately selected from the type of polymerization initiator to be used. The polymerization time is usually 0.5 to 100 hours, preferably 1 to 10 hours.

The emulsion polymerization reaction is an exothermic reaction, and if not controlled, the temperature rises and the polymerization reaction may be shortened. However, in the present invention, the emulsion polymerization reaction temperature is usually 35 ° C. or less, preferably 0 to 35 ° C. is 5 to 30 ° C., particularly preferably controlled to 10 to 25 ° C., the strength characteristics of the acrylic rubber produced and the processability during kneading such as Banbury are highly balanced and suitable.

(post-addition of chain transfer agent)

In the present invention, it is characterized in that the chain transfer agent is added batchwise and post-added during polymerization without initially adding, and by doing so, it is possible to produce an acrylic rubber in which a high-molecular-weight component and a low-molecular-weight component are separated, and also produced The strength characteristics of acrylic rubber and processability during kneading such as rolls are highly balanced and suitable.

The chain transfer agent used is not particularly limited as long as it is usually used in emulsion polymerization, and for example, a mercaptan compound can be suitably used.

As the mercaptan compound, an alkyl mercaptan compound having usually 2 to 20 carbon atoms, preferably an alkyl mercaptan compound having 5 to 15 carbon atoms, and more preferably an alkyl mercaptan compound having 6 to 14 carbon atoms can be used.

The alkyl mercaptan compound may be any of n-alkyl mercaptan compounds, sec-alkyl mercaptan compounds, and t-alkyl mercaptan compounds, but preferably n-alkyl mercaptan compounds and t-alkyl mercaptan compounds. , more preferably an n-alkylmercaptan compound, it is suitable because it can stably exhibit the effect of a chain transfer agent and can highly improve the workability of the acrylic rubber produced, such as a roll.

Specific examples of the alkyl mercaptan compound include n-pentyl mercaptan, n-hexyl mercaptan, n-heptyl mercaptan, n-octyl mercaptan, n-decyl mercaptan, n-dodecyl mercaptan, and n-tri Decylmercaptan, n-tetradecylmercaptan, n-hexadecylmercaptan, n-octadecylmercaptan, sec-pentylmercaptan, sec-hexylmercaptan, sec-heptylmercaptan, sec-octylmercaptan, sec -decylmercaptan, sec-dodecylmercaptan, sec-tridecylmercaptan, sec-tetradecylmercaptan, sec-hexadecylmercaptan, sec-octadecylmercaptan, t-pentylmercaptan, t-hexylmer Captan, t-heptylmercaptan, t-octylmercaptan, t-decylmercaptan, t-dodecylmercaptan, t-tridecylmercaptan, t-tetradecylmercaptan, t-hexadecylmercaptan, t- Octadecyl mercaptan etc. are mentioned, Preferably they are n-octyl mercaptan, n-dodecyl mercaptan, t-dodecyl mercaptan, More preferably, they are n-octyl mercaptan and n-dodecyl mercaptan. .

These chain transfer agents can be used individually or in combination of 2 or more types, respectively. The amount of chain transfer agent used is not particularly limited, but is usually 0.0001 to 1 part by weight, preferably 0.0005 to 0.5 part by weight, more preferably 0.001 to 0.5 part by weight, particularly preferably 0.001 to 0.5 part by weight, based on 100 parts by weight of the monomer components. When it is in the range of 0.005 to 0.1 parts by weight, most preferably 0.01 to 0.06 parts by weight, the strength characteristics and roll workability of the acrylic rubber produced are highly balanced and suitable.

In the present invention, it is characterized in that the chain transfer agent is not added at the beginning of the polymerization but added batchwise during the polymerization, and the high molecular weight component and the low molecular weight component of the acrylic rubber to be produced are prepared, and the molecular weight distribution is set to a specific range. It is suitable because it can highly balance strength characteristics and workability such as rolls.

The number of batchwise post-additions of the chain transfer agent is not particularly limited and is appropriately selected depending on the purpose of use, but is usually 1 to 5 times, preferably 2 to 4 times, more preferably 2 to 3 times, particularly preferably It is suitable because it can highly balance the strength characteristics of the acrylic rubber produced and the processability of rolls etc. at the time of 2 times.

The starting timing of the batchwise post-addition of the chain transfer agent is not particularly limited and is appropriately selected depending on the purpose of use, but is usually 20 minutes after the start of polymerization, preferably 30 minutes after the start of polymerization, more preferably after the start of polymerization. The range of 30 to 200 minutes, particularly preferably 35 to 150 minutes after the start of polymerization, and most preferably 40 to 120 minutes, is suitable because the strength characteristics of the acrylic rubber produced and workability such as rolls can be highly balanced.

The addition amount per batch in the batchwise post-addition of the chain transfer agent is not particularly limited and is appropriately selected depending on the purpose of use, but is usually 0.00005 to 0.5 parts by weight, preferably 0.0001 to 0.1 parts by weight, based on 100 parts by weight of the monomer components. parts, more preferably 0.0005 to 0.05 parts by weight, particularly preferably 0.001 to 0.03 parts by weight, and most preferably 0.002 to 0.02 parts by weight, the strength characteristics and roll processability of the acrylic rubber produced can be highly balanced. suitable

After the addition of the chain transfer agent, there is no particular limitation, but the polymerization reaction can be continued for usually 30 minutes or more, preferably 45 minutes or more, and more preferably 1 hour or more, and then terminated.

(post-addition of reducing agent)

In the present invention, the reducing agent for the redox catalyst can be added post-added during the polymerization, which is suitable because it can highly balance the strength characteristics of the acrylic rubber produced and the workability of rolls and the like.

As the reducing agent added later during polymerization, the examples and preferred ranges of the reducing agent described above are the same. In the present invention, as the reducing agent to be added later, ascorbic acid or a salt thereof is suitable.

The amount of the reducing agent added later during polymerization is not particularly limited and may be appropriately selected depending on the purpose of use, but is usually 0.0001 to 1 part by weight, preferably 0.0005 to 0.5 part by weight, more preferably 0.0005 to 0.5 part by weight, based on 100 parts by weight of the monomer components. Preferably in the range of 0.001 to 0.5 parts by weight, particularly preferably in the range of 0.005 to 0.1 parts by weight, and most preferably in the range of 0.01 to 0.05 parts by weight, the productivity of acrylic rubber production is excellent and the strength characteristics and processability of the acrylic rubber produced are highly balanced It is suitable because it can be done.

The reducing agent added later during polymerization may be either continuous or batchwise, but is preferably batchwise. The number of times when the reducing agent is post-added batchwise during polymerization is not particularly limited, but is usually 1 to 5 times, preferably 1 to 3 times, and more preferably 1 to 2 times.

The ratio of the amount of ascorbic acid or a salt thereof added initially and the amount of ascorbic acid or a salt thereof added later when the reducing agent added later during the initial stage of polymerization and during the polymerization is ascorbic acid or a salt thereof is not particularly limited, but is referred to as "initial addition". The weight ratio of "ascorbic acid or a salt thereof"/"post-added ascorbic acid or a salt thereof batchwise" is usually 1/9 to 8/2, preferably 2/8 to 6/4, more preferably 3/7 When it is in the range of ~ 5/5, the productivity of acrylic rubber production is excellent and it is suitable because it can highly balance the strength characteristics and processability of the acrylic rubber produced.

The timing of the post-addition of the reducing agent is not particularly limited and is appropriately selected depending on the purpose of use, but is usually within the range of 1 hour after the initiation of polymerization, preferably 1 to 3 hours after initiation of polymerization, more preferably 1.5 to 2.5 hours. At the same time, the productivity of acrylic rubber production is excellent, and at the same time, it is suitable because it can highly balance the strength characteristics of the acrylic rubber and the workability of rolls.

The addition amount per batch in the batchwise post-addition of the reducing agent is not particularly limited and is appropriately selected depending on the purpose of use, but is usually 0.00005 to 0.5 parts by weight, preferably 0.0001 to 0.1 parts by weight, based on 100 parts by weight of the monomer components. , More preferably 0.0005 to 0.05 parts by weight, particularly preferably 0.001 to 0.03 parts by weight, it is suitable because the strength characteristics of the acrylic rubber produced and workability such as rolls can be highly balanced.

The operation after addition of the reducing agent is not particularly limited, but the polymerization reaction can be terminated after continuing the polymerization reaction for usually 30 minutes or longer, preferably 45 minutes or longer, more preferably 1 hour or longer.

The polymerization conversion ratio in the emulsion polymerization reaction is not particularly limited, but is usually 90% by weight or more, preferably 95% by weight or more, and the acrylic rubber produced at this time has excellent strength characteristics and is suitable because it does not have a monomer odor. In terminating polymerization, you may use a polymerization terminator.

(solidification process)

The coagulation step after emulsion polymerization is characterized in that the emulsion polymerization solution obtained in the emulsion polymerization described above is added to the stirred coagulation solution and solidified to form a hydrous crumb of acrylic rubber.

The solid content concentration of the emulsion polymerization liquid used in this coagulation reaction is not particularly limited, but is usually 5 to 50% by weight, preferably 10 to 45% by weight, more preferably adjusted to the range of 20 to 40% by weight.

The coagulant for the coagulating solution used is not particularly limited, but metal salts are usually used. Examples of the metal salt include alkali metal salts, periodic table Group 2 metal salts, and other metal salts, preferably alkali metal salts and periodic table Group 2 metal salts, more preferably periodic table Group 2 metal salts. , Particularly preferably, when a magnesium salt is used, the water resistance, strength characteristics, mold release properties, and workability of the obtained acrylic rubber can be highly balanced, so it is suitable.

Examples of alkali metal salts include sodium salts such as sodium chloride, sodium nitrate, and sodium sulfate; Potassium salts, such as potassium chloride, potassium nitrate, and potassium sulfate; Lithium salts, such as lithium chloride, lithium nitrate, and lithium sulfate, etc. are mentioned, Among these, sodium salt is preferable, and sodium chloride and sodium sulfate are especially preferable.

Examples of the Group 2 metal salt of the periodic table include magnesium chloride, calcium chloride, magnesium nitrate, calcium nitrate, magnesium sulfate, and calcium sulfate, and calcium chloride and magnesium sulfate are preferable.

Examples of other metal salts include zinc chloride, titanium chloride, manganese chloride, iron chloride, cobalt chloride, nickel chloride, aluminum chloride, tin chloride, zinc nitrate, titanium nitrate, manganese nitrate, iron nitrate, cobalt nitrate, and nickel nitrate. , aluminum nitrate, tin nitrate, zinc sulfate, titanium sulfate, manganese sulfate, iron sulfate, cobalt sulfate, nickel sulfate, aluminum sulfate, tin sulfate and the like.

These coagulants can be used individually or in combination of two or more, and the amount used is usually 0.01 to 100 parts by weight, preferably 0.1 to 50 parts by weight, more preferably 0.1 to 50 parts by weight, based on 100 parts by weight of the monomer component. is in the range of 1 to 30 parts by weight. When the coagulant is within this range, it is suitable because the compression set resistance and water resistance can be highly improved when the acrylic rubber is crosslinked while ensuring sufficient coagulation of the acrylic rubber.

In the coagulation step of the present invention, by concentrating the grain size of the resulting hydrous crumb in a specific region, the cleaning efficiency and the ash removal efficiency during dehydration are remarkably increased, which is suitable. The ratio of the resulting hydrous crumbs in the range of 710 μm to 6.7 mm (passing through 6.7 mm without passing through 710 μm) is not particularly limited, but is usually 30% by weight or more, preferably 50 The water resistance of the acrylic rubber can be remarkably improved when it is more than 60% by weight, more preferably 60% by weight or more, particularly preferably 70% by weight or more, and most preferably 80% by weight or more, so it is suitable. In addition, the ratio of the resulting hydrous crumbs in the range of 710 μm to 4.75 mm (passing through 4.75 mm without passing through 710 μm) is not particularly limited, but is usually 30% by weight or more, preferably When is 50% by weight or more, more preferably 60% by weight or more, particularly preferably 70% by weight or more, and most preferably 80% by weight or more, it is suitable because the water resistance of the acrylic rubber can be remarkably improved. In addition, the ratio of the resulting hydrous crumbs in the range of 710 μm to 3.35 mm (passing through 3.35 mm without passing through 710 μm) is not particularly limited, but is usually 20% by weight or more, preferably When is 30% by weight or more, more preferably 40% by weight or more, particularly preferably 50% by weight or more, and most preferably 60% by weight or more, it is suitable because the water resistance of the acrylic rubber can be remarkably improved.

The means for generating the particle size of the hydrous crumb within the above range is not particularly limited, but, for example, adding a contact method between the emulsion polymerization liquid and the coagulant to the coagulant liquid (aqueous coagulant solution) in which the emulsion polymerization liquid is stirred. Alternatively, the concentration of the coagulant in the coagulating liquid, the number of agitation and the circumferential speed of the coagulating liquid being stirred can be specified.

The coagulant liquid used is usually used as an aqueous solution, but the concentration of the coagulant in the aqueous solution is not particularly limited, but is usually 0.1% by weight or more, preferably 0.5% by weight or more, more preferably 1% by weight or more, particularly Preferably it is 1.5% by weight or more. The concentration of the coagulant in the coagulating solution is usually 0.1 to 20% by weight, preferably 0.5 to 15% by weight, more preferably 1 to 10% by weight, particularly preferably 1.5 to 5% by weight. It is suitable because it can uniformly focus the grain size of hydrous crumbs in a specific area.

The temperature of the coagulating solution is not particularly limited, but is suitable because uniform moistened crumbs are formed when it is usually in the range of 40 ° C. or higher, preferably 40 to 90 ° C., more preferably 50 to 80 ° C.

The number of stirring (number of rotations) of the coagulating liquid being stirred is, that is, the number of rotations of the stirring blades of the stirring device, and is not particularly limited, but is usually 100 rpm or more, preferably 200 rpm or more, more preferably 200 to 1000 rpm, particularly preferably 300 to 900 rpm, most preferably 400 to 800 rpm.

As for the number of revolutions, the number of rotations that are vigorously stirred to a certain extent is suitable because the grain size of the resulting hydrous crumbs can be made small and uniform. It can be carried out, and the control of the coagulation reaction can be made easier by setting it below the said upper limit.

The circumferential speed of the coagulating solution being stirred, that is, the speed of the outer circumference of the stirring blades of the stirring device, is not particularly limited. Suitable, usually 0.5 m/s or more, preferably 1 m/s or more, more preferably 1.5 m/s or more, particularly preferably 2 m/s or more, and most preferably 2.5 m/s or more. On the other hand, the upper limit of the circumferential speed is not particularly limited, but usually solidifies when it is 50 m/s or less, preferably 30 m/s or less, more preferably 25 m/s or less, and most preferably 20 m/s or less. It is suitable because the control of the reaction becomes easy.

The shape and crumbs of the hydrous crumbs produced by setting the above conditions of the coagulation reaction (adding method, solid content concentration of the emulsion polymerization solution, concentration and temperature of the coagulation solution, rotation speed and circumferential speed during stirring of the coagulation solution, etc.) within a specific range It is suitable because the diameter is uniform and concentrated, the removal of the emulsifier and the coagulant during washing and dehydration is remarkably improved, and as a result, the water resistance and storage stability of the produced acrylic rubber can be highly improved.

(cleaning process)

The washing step in the method for producing acrylic rubber of the present invention is characterized by washing the hydrous crumb produced in the solidification reaction with hot water.

The cleaning method is not particularly limited, and for example, the resulting hydrous crumb can be mixed with a large amount of hot water.

The amount of hot water added for washing is not particularly limited, but the amount per water washing is usually 50 parts by weight or more, preferably 50 to 15,000 parts by weight, more preferably 100 to 15,000 parts by weight, based on 100 parts by weight of the monomer components. When it is in the range of 10,000 parts by weight, more preferably 500 to 5,000 parts by weight, it is suitable because the amount of ash in acrylic rubber can be effectively reduced.

The temperature of the hot water to be used is not particularly limited, but is usually 40 ° C. or higher, preferably 40 to 100 ° C., more preferably 50 to 90 ° C., and especially 60 to 80 ° C., the cleaning efficiency can be significantly increased. Optimal. By setting the temperature of the water to be used equal to or higher than the above lower limit, the emulsifier and the coagulant are released from the hydrous crumb, and the cleaning efficiency is further improved.

The washing time is not particularly limited, but is usually in the range of 1 to 120 minutes, preferably 2 to 60 minutes, and more preferably 3 to 30 minutes.

The number of times of washing (washing with water) is also not particularly limited, and is usually 1 to 10 times, preferably 1 to 5 times, and more preferably 2 to 3 times. On the other hand, from the viewpoint of reducing the residual amount of the coagulant in the finally obtained acrylic rubber, it is preferable to increase the number of times of washing with water. By setting it as the range of, the number of times of washing with water can be reduced remarkably.

(Dehydration process)

The dewatering step in the method for producing acrylic rubber of the present invention is a step of dehydrating the washed hydrous crumb.

There is no particular limitation on the dewatering method of the hydrous crumb, as long as it is a method capable of squeezing moisture out of the hydrous crumb, and it can usually be carried out using a dehydrator or the like. This reduces the amount of ash of the emulsifier or coagulant inherent in the hydrous crumb, which could not be removed in the washing step, and remarkably improves the water resistance of the acrylic rubber, so it is suitable.

The dehydrator is not particularly limited, and for example, a centrifugal separator, a squeezer, a screw type extruder, etc. can be used. In particular, a screw type extruder is suitable because it can highly reduce the water content of the hydrous crumb. In a centrifugal separator or the like, the adhesive acrylic rubber adheres between the wall surface and the slit, and usually only about 45 to 55% by weight can be dehydrated. On the other hand, a screw-type extruder is suitable because it has a mechanism for forcibly squeezing out water.

The water content of the hydrous crumb after dehydration is not limited, but is usually in the range of 1 to 50% by weight, preferably 1 to 40% by weight, more preferably 10 to 40% by weight, and more preferably 15 to 35% by weight. . By setting the water content after dehydration to the above lower limit or more, the dehydration time can be shortened and deterioration of the acrylic rubber can be suppressed, while the ash content can be sufficiently reduced by setting it to the above upper limit or less.

(drying process)

The drying step in the method for producing acrylic rubber of the present invention is a step of drying the dehydrated hydrous crumb to less than 1% by weight.

The method of drying the dewatered crumb after dehydration is not particularly limited, but for example, the dehydrated crumb may be dried by direct drying, but preferably using a screw-type twin-screw extrusion dryer. The screw-type twin-screw extrusion dryer used is not particularly limited as long as it is an extrusion dryer having two screws, but in the present invention, in particular, a screw-type twin screw extrusion dryer having two screws is used under conditions of high share. It is suitable because it can highly balance the roll processability, Banbury processability, and strength characteristics of acrylic rubber obtained by drying the hydrous crumb.

In the present invention, acrylic rubber can be obtained by melting hydrous crumb in a screw-type twin-screw extrusion dryer and extruding and drying it. The drying temperature (set temperature) of the screw-type twin-screw extrusion dryer may be appropriately selected, but is usually 100 to 250°C, preferably 110 to 200°C, and more preferably 120 to 180°C. It is suitable for efficient drying without thermal deterioration or deterioration.

In the present invention, when the water-containing crumb is melted and extruded under reduced pressure in a screw-type twin-screw extrusion dryer, the storage stability can be highly improved without impairing the roll processability and strength characteristics of the acrylic rubber, so it is suitable. At this stage, in order to remove the air inherent in the acrylic rubber and increase the storage stability, the suitable depressurization degree in the screw-type twin-screw extrusion dryer may be appropriately selected, but is usually 1 to 50 kPa, preferably 2 to 30 kPa, and more. It is preferably in the range of 3 to 20 kPa.

In the present invention, when the water-containing crumb is melt-kneaded and dried in a state in which water is almost removed with a screw-type twin-screw extrusion dryer, the Banbury processability can be highly improved without impairing the roll processability or strength characteristics of acrylic rubber. suitable In a state where most of the water can be highly improved in Banbury workability, it may be appropriately selected, but the water content of acrylic rubber is usually less than 1% by weight, preferably 0.8% by weight or less, more preferably 0.6% by weight or less. . On the other hand, "melt kneading" or "melt kneading and drying" as used in the present invention means that acrylic rubber is kneaded (mixed) in a molten state or extruded in a molten state in a screw-type twin screw extrusion dryer, and then dried at that stage. Or, it means that acrylic rubber is kneaded in a molten (plasticized) state by a screw-type twin-screw extrusion dryer, extruded, and dried.

The maximum torque of the screw-type twin-screw extrusion dryer used in the present invention is not particularly limited, but is usually 20 N m or more, preferably 25 N m or more, more preferably 30 N m or more, particularly preferably Preferably it is 35 N·m or more, and most preferably 40 N·m or more. The maximum torque of the screw type twin screw extrusion dryer used in the present invention is also usually 25 to 125 N m, preferably 30 to 100 N m, more preferably 35 to 75 N m, particularly preferably When is in the range of 40 to 60 N·m, it is suitable because it can highly balance the roll processability, Banbury processability, and strength characteristics of the acrylic rubber to be produced.

The specific power of the screw-type twin-screw extrusion dryer used in the present invention is not particularly limited, but is usually 0.1 to 0.25 [kw h / kg] or more, preferably 0.13 to 0.23 [kw h / kg], more preferably More specifically, in the range of 0.15 to 0.2 [kw h/kg], the roll processability, Banbury processability, and strength characteristics of the obtained acrylic rubber are highly balanced and suitable.

The specific power of the screw-type twin-screw extrusion dryer used in the present invention is not particularly limited, but is usually 0.2 to 0.6 [A h / kg] or more, preferably 0.25 to 0.55 [A h / kg], more preferably More specifically, in the range of 0.35 to 0.5 [A h/kg], the roll processability, Banbury processability, and strength characteristics of the obtained acrylic rubber are highly balanced and suitable.

The shear rate of the screw-type twin-screw extrusion dryer used in the present invention is not particularly limited, but is usually 40 to 150 [1/s] or more, preferably 45 to 125 [1/s], more preferably 50 to 150 [1/s]. In the range of 100 [1/s], the storage stability, roll processability, Banbury processability and strength characteristics of the obtained acrylic rubber are highly balanced and suitable.

The shear viscosity of the acrylic rubber in the screw-type twin screw extrusion dryer used in the present invention is not particularly limited, but is usually 4000 to 8000 [Pa s] or less, preferably 4500 to 7500 [Pa s], more preferably In the range of 5000 to 7000 [Pa s], the storage stability, roll processability, Banbury processability and strength characteristics of the obtained acrylic rubber are highly balanced and suitable.

The acrylic rubber of the present invention is cooled after melt kneading and drying. The cooling rate is not particularly limited, but is usually 40°C/hr or more, preferably 50°C/hr or more, more preferably 100°C/hr or more, and particularly preferably 150°C/hr or more. It has excellent storage stability, roll processability, Banbury processability, strength characteristics, water resistance and compression set resistance, and is suitable because it can significantly improve scorch stability.

The acrylic rubber of the present invention thus obtained is excellent in roll processability, strength characteristics and water resistance, and can be used for various purposes. The shape of the acrylic rubber of the present invention is not particularly limited and is selected according to the purpose of use, and examples thereof include powder, crumb, strand, sheet, and veil. However, it is suitable because of its excellent storage stability.

(Method for producing sheet-like or veil-like acrylic rubber)

The method for producing sheet-like or veil-like acrylic rubber of the present invention is not particularly limited, but the water-containing crumb after washing is prepared by a dehydration barrel having a dehydration slit, a drying barrel under reduced pressure, and a screw-type twin-screw extrusion dryer having a die at the tip. After dehydration to a water content of 1 to 40% by weight in a dehydration barrel using a dehydration barrel, drying to less than 1% by weight in a drying barrel to extrude sheet-like dry rubber from a die, sheet-like acrylic rubber can be easily produced. A veiled acrylic rubber can be easily produced by laminating and baling the sheet-like dry rubber.

In the present invention, it is preferable that the water-containing crumb supplied to the screw-type twin-screw extrusion dryer is one in which free water is removed (moisture removal) after washing.

(moisture removal process)

In the present invention, providing a water removal step in which free water is separated from the water-containing crumb after washing with a water remover is suitable for increasing the dewatering efficiency.

As the moisture eliminator, known ones can be used without particular limitation, and examples thereof include wire meshes, screens, rolling elements, and the like, and preferably wire meshes and screens.

The size of the eyes of the water remover is not particularly limited, but is usually in the range of 0.01 to 5 mm, preferably 0.1 to 1 mm, and more preferably 0.2 to 0.6 mm, so that the loss of the water-containing crumb is small and the water removal is efficient. It is suitable.

The water content of the water-containing crumb after water removal, that is, the water content of the water-containing crumb introduced into the dewatering/drying step is not particularly limited, but is usually 50 to 80% by weight, preferably 50 to 70% by weight, more preferably 50 to 80% by weight. It is in the range of 60% by weight.

The temperature of the water-containing crumb after water removal, that is, the temperature of the water-containing crumb introduced into the dewatering and drying step is not particularly limited, but is usually 40 ° C. or higher, preferably 40 to 100 ° C., more preferably 50 to 90 ° C. Especially preferably in the range of 55 to 85 ° C, most preferably 60 to 80 ° C, the specific heat is 1.5 to 2.5 KJ / kg K, like the acrylic rubber of the present invention, so that it is difficult to increase the temperature. It is suitable because it can dehydrate and dry efficiently using a twin-screw extrusion dryer.

(Dehydration of hydrous crumb in dehydration barrel part)

Dehydration of the water-containing crumb is performed in a dewatering barrel in a screw-type twin-screw extrusion dryer having a dehydration slit. The size of the eyes of the dewatering slit may be appropriately selected depending on the conditions of use, but when it is in the range of usually 0.01 to 5 mm, preferably 0.1 to 1 mm, and more preferably 0.2 to 0.6 mm, the loss of the water-containing crumb is small and the water-containing crumb is small. It is suitable for efficient dehydration.

The number of dewatering barrels in the screw-type twin-screw extrusion dryer is not particularly limited, but is usually plural, preferably 2 to 10, more preferably 3 to 6, so that the adhesive acrylic rubber can be dehydrated efficiently. good in doing

There are two types of removal of water from the brine crumb in the dewatering barrel: removal in liquid phase from the dewatering slit (drainage) and removal in vapor phase (double steam). In the present invention, drainage is dehydration, Double steam is distinguished by defining it as pre-drying.

Water discharged from the dewatering slit in the dewatering of the hydrous crumb may be in either liquid phase (drainage) or vapor phase (exhaust steam). Combining drainage and steam drainage makes it possible to efficiently dehydrate the adhesive acrylic rubber and is suitable. The selection of a drain type dewatering barrel or a double steam type dehydration barrel of a screw type twin screw extrusion dryer having three or more dehydration barrels may be appropriately performed depending on the purpose of use. In the case of reducing, the number of drain type barrels is increased, and in the case of reducing the water content, the number of double steam type barrels is increased.

The set temperature of the dewatering barrel is appropriately selected depending on the monomer composition of the acrylic rubber, ash content, water content, operating conditions, etc., but is usually 60 to 150 ° C, preferably 70 to 140 ° C, more preferably 80 to 130 ° C. is the range The set temperature of the dewatering barrel for dehydration in the drained state is usually 60 to 120°C, preferably 70 to 110°C, and more preferably 80 to 100°C. The set temperature of the dewatering barrel for dewatering in the double steam state is usually in the range of 100 to 150°C, preferably 105 to 140°C, and more preferably 110 to 130°C.

The water content after dewatering in drainage type dehydration in which water is squeezed out of the water-containing crumb is not particularly limited, but is usually 1 to 40% by weight, preferably 5 to 40% by weight, more preferably 5 to 35% by weight, particularly preferably When it is 10 to 35% by weight, productivity and ash removal efficiency are highly balanced and suitable.

When dehydration of adhesive acrylic rubber having reactive groups is performed using a centrifugal separator or the like, the acrylic rubber adheres to the dehydration slit and dehydration is hardly possible (moisture content is up to about 45 to 55% by weight), but in the present invention , By using a screw-type twin-screw extrusion dryer having a dewatering slit and forcibly squeezed with a screw, it became possible to reduce the water content up to this point.

In the case of dewatering the water-containing crumb in the case of providing a drain type dewatering barrel and a double steam type dewatering barrel, the water content after drainage in the drain type dewatering barrel part is usually 5 to 40% by weight, preferably 10 to 40% by weight, more preferably It is preferably 15 to 35% by weight, and the water content after preliminary drying in the double steam type dewatering barrel is usually 1 to 30% by weight, preferably 3 to 20% by weight, and more preferably 5 to 15% by weight.

By setting the water content after dehydration to the above lower limit or more, the dehydration time can be shortened and deterioration of the acrylic rubber can be suppressed, and by setting it to the above upper limit or less, the amount of ash can be sufficiently reduced.

(Drying of water-containing crumbs in the drying barrel part)

The drying of the hydrous crumb after dehydration is preferably performed in a drying barrel under reduced pressure using a screw-type twin-screw extrusion dryer having a drying barrel. By drying the acrylic rubber under reduced pressure, the production efficiency of drying is increased, and air inherent in the acrylic rubber is removed, and sheet-like or veil-like acrylic rubber having high specific gravity and excellent storage stability can be produced, which is suitable. In the present invention, storage stability can be further improved to a high degree by melting acrylic rubber under reduced pressure and extruding and drying it. The storage stability of acrylic rubber can be largely controlled in correlation with the specific gravity of the acrylic rubber, but in the case of controlling high storage stability with a large specific gravity, it can be controlled by the degree of reduced pressure in extrusion drying or the like.

The depressurization degree of the drying barrel may be appropriately selected, but when it is usually 1 to 50 kPa, preferably 2 to 30 kPa, and more preferably 3 to 20 kPa, the hydrous crumb can be efficiently dried and the air in the acrylic rubber can be removed. It is suitable because it can remarkably improve the storage stability of sheet-like or veil-like acrylic rubber by removing it.

The set temperature of the drying barrel may be appropriately selected, but when it is in the range of usually 100 to 250 ° C, preferably 110 to 200 ° C, more preferably 120 to 180 ° C, it dries efficiently without thermal deterioration or deterioration of acrylic rubber. and can reduce the amount of insoluble methyl ethyl ketone in sheet-like or veil-like acrylic rubber.

The number of drying barrels in the screw-type twin-screw extrusion dryer is not particularly limited, but is usually plural, preferably 2 to 10, and more preferably 3 to 8. The decompression degree in the case of having a plurality of drying barrels may be an approximate decompression degree in all the drying barrels, or may be changed. In the case of having a plurality of drying barrels, the set temperature may be approximated or changed in all drying barrels. It is suitable because it can increase efficiency.

The water content of the dried rubber after drying is usually less than 1% by weight, preferably 0.8% by weight or less, and more preferably 0.6% by weight or less. In the present invention, especially in the screw-type twin-screw extrusion dryer, the water content of dry rubber is set to this value (a state in which water is almost removed) and melt-extruded to reduce the amount of methyl ethyl ketone insoluble in sheet-like or veil-like acrylic rubber It is suitable because it can be reduced. In the present invention, acrylic rubber melt-kneaded or melt-kneaded and dried with a screw-type twin-screw extrusion dryer is suitable because both characteristics of strength characteristics and Banbury workability are highly balanced. On the other hand, "melt kneading" or "melt kneading and drying" as used in the present invention means that acrylic rubber is kneaded (mixed) in a molten state or extruded in a molten state in a screw-type twin screw extrusion dryer, and then dried at that stage. Or, it means that acrylic rubber is kneaded in a molten (plasticized) state by a screw-type twin-screw extrusion dryer, extruded, and dried.

In the present invention, the shear rate applied in the drying barrel of the screw-type twin-screw extrusion dryer in a state where the acrylic rubber does not substantially contain water is not particularly limited, but is usually 10 [1/s] or more , Preferably in the range of 10 to 400 [1/s], more preferably in the range of 50 to 250 [1/s], the storage stability, roll processability, Banbury processability, strength characteristics, and The compression set resistance is highly balanced and suitable.

The shear viscosity of the acrylic rubber in the screw-type twin-screw extrusion dryer used in the present invention, particularly in the drying barrel, is not particularly limited, but is usually 12000 [Pa s] or less, preferably 1000 to 12000 [Pa s]. ], more preferably 2000 to 10000 [Pa s], particularly preferably 3000 to 7000 [Pa s], most preferably 4000 to 6000 [Pa s] in the form of a sheet or veil obtained The storage stability, roll processability, Banbury processability and strength characteristics of acrylic rubber are highly balanced and suitable.

(Extrusion of dry rubber from die part)

The dry rubber dehydrated and dried in the screw portion of the dewatering barrel and the drying barrel is sent to the screwless straightening die portion, and extruded from the die portion into a desired shape. Between the screw portion and the die portion, a breaker plate or wire mesh may or may not be provided.

The extruded dry rubber is suitable because, by making the die shape substantially rectangular and feeding it out in a sheet form, a dry rubber excellent in storage stability with little mixing of air and high specific gravity is obtained.

The resin pressure in the die portion is not particularly limited, but is usually in the range of 0.1 to 10 MPa, preferably 0.5 to 5 MPa, and more preferably 1 to 3 MPa. Sheet-like or veil-like acrylic rubber It is suitable because there is little mixing of air (specific gravity is high) and productivity is excellent.

Screw type twin screw extrusion dryer and operating conditions

The screw length (L) of the screw type twin screw extrusion dryer used may be appropriately selected depending on the purpose of use, but is usually in the range of 3000 to 15000 mm, preferably 4000 to 10000 mm, and more preferably 4500 to 8000 mm. .

The screw diameter (D) of the screw type twin screw extrusion dryer used may be appropriately selected depending on the purpose of use, but is usually in the range of 50 to 250 mm, preferably 100 to 200 mm, and more preferably 120 to 160 mm. .

The ratio (L/D) of the screw length (L) to the screw diameter (D) of the screw type twin screw extrusion dryer used is not particularly limited, but is usually 10 to 100, preferably 20 to 80, more preferably When is in the range of 30 to 60, it is suitable because the water content can be reduced to less than 1% by weight without causing molecular weight reduction or thermal deterioration of dry rubber.

The number of revolutions (N) of the screw-type twin screw extrusion dryer used may be appropriately selected depending on various conditions, but is usually 10 to 1000 rpm, preferably 50 to 750 rpm, more preferably 100 to 500 rpm, and most preferably More preferably, at 120 to 300 rpm, it is suitable because it can efficiently reduce the water content and methyl ethyl ketone insoluble content of sheet-like or veil-like acrylic rubber.

The extrusion amount (Q) of the screw type twin screw extrusion dryer used is not particularly limited, but is usually 100 to 1,500 kg/hr, preferably 300 to 1200 kg/hr, more preferably 400 to 1000 kg/hr, Most preferably, it is in the range of 500 to 800 kg/hr.

The ratio (Q/N) of the amount of extrusion (Q) and the number of revolutions (N) of the screw-type twin-screw extrusion dryer used is not particularly limited, but is usually 2 to 10, preferably 3 to 8, more preferably is in the range of 4 to 6.

The maximum torque of the screw-type twin-screw extrusion dryer used is not particularly limited, but is usually 30 N·m or more, preferably 35 N·m or more, and more preferably 40 N·m or more. When the maximum torque of the screw-type twin-screw extrusion dryer used in the present invention is in the range of usually 30 to 100 N m, preferably 35 to 75 N m, and more preferably 40 to 60 N m , It is suitable because it can highly balance the roll processability, Banbury processability, and strength characteristics of the sheet-like or veil-like acrylic rubber to be produced.

The specific power of the screw-type twin-screw extrusion dryer used is not particularly limited, but is usually 0.1 to 0.25 [kw h/kg] or more, preferably 0.13 to 0.23 [kw h/kg], more preferably 0.15 When it is in the range of ~0.2 [kw·h/kg], the roll processability, Banbury processability, and strength characteristics of the obtained sheet-like or bale-like acrylic rubber are highly balanced and suitable.

The specific power of the screw-type twin-screw extrusion dryer used is not particularly limited, but is usually 0.2 to 0.6 [A h/kg] or more, preferably 0.25 to 0.55 [A h/kg], more preferably 0.35 In the range of ~ 0.5 [A h / kg], the roll processability, Banbury processability, and strength characteristics of the sheet-like or bale-like acrylic rubber obtained are highly balanced and suitable.

The shear rate of the screw-type twin-screw extrusion dryer used is not particularly limited, but is usually 40 to 150 [1/s] or more, preferably 45 to 125 [1/s], more preferably 50 to 100 [1/s]. /s], the storage stability, roll processability, Banbury processability and strength characteristics of the sheet-like or veil-like acrylic rubber obtained are highly balanced and suitable.

The shear viscosity of the acrylic rubber in the screw-type twin screw extrusion dryer used is not particularly limited, but is usually 4000 to 8000 [Pa s] or less, preferably 4500 to 7500 [Pa s], more preferably 5000 to 8000 [Pa s]. In the range of 7000 [Pa·s], the storage stability, roll processability, Banbury processability and strength characteristics of the sheet-like or bale-like acrylic rubber obtained are highly balanced and suitable.

Thus, in this invention, dehydration, drying, and shaping|molding under conditions of high shear are attained by using the extrusion dryer which has a 2-screw screw, and it is suitable.

(sheet-shaped dry rubber)

The shape of the dry rubber extruded from the screw-type twin-screw extrusion dryer is sheet-like, and at this time, the specific gravity can be increased without entraining air, and the storage stability is highly improved, which is suitable. Sheet-like dry rubber extruded from the screw-type twin-screw extrusion dryer is usually cooled and cut to be used as sheet-like acrylic rubber.

The thickness of the sheet-like dry rubber extruded from the screw-type twin-screw extrusion dryer is not particularly limited, but is usually 1 to 40 mm, preferably 2 to 35 mm, more preferably 3 to 30 mm, and most preferably 5 mm. In the range of ~25 mm, workability and productivity are excellent and suitable. In particular, since the thermal conductivity of the sheet-like dry rubber is as low as 0.15 to 0.35 W/mK, the thickness of the sheet-like dry rubber is usually 1 to 30 mm, preferably 2 to 25 mm, when cooling efficiency is increased and productivity is significantly improved. mm, more preferably in the range of 3 to 15 mm, particularly preferably in the range of 4 to 12 mm.

The width of the sheet-like dry rubber extruded from the screw-type twin-screw extrusion dryer is appropriately selected depending on the purpose of use, but is usually in the range of 300 to 1200 mm, preferably 400 to 1000 mm, and more preferably 500 to 800 mm. .

The temperature of the dried rubber extruded from the screw-type twin-screw extrusion dryer is not particularly limited, but is usually in the range of 100 to 200°C, preferably 110 to 180°C, and more preferably 120 to 160°C.

The water content of the dry rubber extruded from the screw-type twin-screw extrusion dryer is not particularly limited, but is usually less than 1% by weight, preferably 0.8% by weight or less, and more preferably 0.6% by weight or less.

The complex viscosity at 100 ° C. ([η] 100 ° C.) of the sheet-like dry rubber extruded from the screw-type twin-screw extrusion dryer is not particularly limited, but is usually 1500 to 6000 [Pa s], preferably 2000 In the range of to 5000 [Pa s], more preferably 2500 to 4000 [Pa s], and most preferably 2500 to 3500 [Pa s], the extrudability and shape retention properties as a sheet are highly balanced and suitable. . That is, by setting it to the lower limit or more, extrudability can be made more excellent, and by setting it to the upper limit or less, the shape collapse and breakage of the sheet-shaped dry rubber can be suppressed.

The sheet-like dry rubber extruded from the screw-type twin-screw extrusion dryer may be folded as it is and used, but usually it can be cut and used.

The cutting of the sheet-like dry rubber is not particularly limited, but since the acrylic rubber of the present invention has strong adhesiveness, it is preferable to cool the sheet-like dry rubber in order to continuously cut it without entraining air.

The cutting temperature of the sheet-like dry rubber is not particularly limited, but is usually 60°C or lower, preferably 55°C or lower, and more preferably 50°C or lower, as cutting properties and productivity are highly balanced and suitable.

The complex viscosity ([η] 60°C) of the sheet-like dry rubber at 60°C is not particularly limited, but is usually 15,000 [Pa s] or less, preferably 2000 to 10,000 [Pa s], more preferably Preferably, when it is in the range of 2500 to 7000 [Pa s], most preferably 2700 to 5500 [Pa s], it is suitable because it can be cut continuously without entraining air.

The ratio of the complex viscosity at 100°C ([η]100°C) to the complex viscosity at 60°C ([η]60°C) of the sheet-like dry rubber ([η]100°C/[η]60°C) is , is not particularly limited, and may be appropriately selected depending on the purpose of use, but is usually 0.5 or more, preferably 0.6 or more, more preferably 0.7 or more, particularly preferably 0.8 or more, and most preferably 0.85 or more, and the upper limit is usually When 0.98 or less, preferably 0.97 or less, more preferably 0.96 or less, particularly preferably 0.95 or less, and most preferably 0.93 or less, air entrainment is low, and cutting and productivity are highly balanced and suitable.

The cooling method of the sheet-like dry rubber is not particularly limited and may be left at room temperature. However, since the thermal conductivity of the sheet-like dry rubber is very small at 0.15 to 0.35 W/mK, an air cooling method under blowing or air conditioning, or spraying water Forced cooling such as a splashing method or an immersion method in which water is immersed in water is preferable because it increases productivity, and an air cooling method under blowing or cooling is particularly suitable.

In the air-cooling method of sheet-like dry rubber, for example, sheet-like dry rubber can be extruded from a screw extruder onto a conveying machine such as a belt conveyor, conveyed and cooled while blowing cold air. The temperature of the cold air is not particularly limited, but is usually in the range of 0 to 25°C, preferably 5 to 25°C, and more preferably 10 to 20°C. The length to be cooled is not particularly limited, but is usually in the range of 5 to 500 m, preferably 10 to 200 m, and more preferably 20 to 100 m. The cooling rate of the sheet-like dry rubber is not particularly limited, but is usually 40°C/hr or more, preferably 50°C/hr or more, more preferably 100°C/hr or more, and particularly preferably 150°C/hr or more. It is suitable for cutting easily at times and not entraining air, so that storage stability can be improved. In the present invention, the cooling rate of the sheet-shaped dry rubber is usually 40°C/hr or more, preferably 50°C/hr or more, more preferably 100°C/hr or more, and particularly preferably 150°C/hr or more. In the case of the above, the scorch stability when used as an acrylic rubber composition is remarkably excellent and suitable.

The cut length of the sheet-like dry rubber is not particularly limited and is appropriately selected depending on the purpose of use, but is usually in the range of 100 to 800 mm, preferably 200 to 500 mm, and more preferably 250 to 450 mm.

The sheet-like acrylic rubber obtained in this way has excellent maneuverability compared to crumb-like acrylic rubber, and is also excellent in roll processability, crosslinkability, strength characteristics and compression set resistance, as well as storage stability, Banbury workability and water resistance. , It can be used as it is or layered and veiled.

(lamination process)

The method for producing the veil-like acrylic rubber of the present invention is not particularly limited, but it is suitable because veil-like acrylic rubber with less entrainment of air and excellent storage stability is obtained by laminating the sheet-like acrylic rubber.

The lamination temperature of the sheet-like acrylic rubber is not particularly limited, but it is suitable when it is usually 30°C or higher, preferably 35°C or higher, and more preferably 40°C or higher, since air entrained during lamination can be released. The number of laminated sheets may be appropriately selected according to the size or weight of the veil-like acrylic rubber. The veil-like acrylic rubber of the present invention is integrated by the dead weight of the laminated sheet-like acrylic rubber.

The veil-like acrylic rubber of the present invention thus obtained is superior in operability compared to crumb-like acrylic rubber, and is also excellent in roll processability, crosslinkability, strength characteristics and compression set resistance, storage stability, Banbury processability and water resistance. It is also excellent, and the veil-shaped acrylic rubber can be used as it is or after cutting the necessary amount and putting it into a mixer such as a banbury or roll.

<Rubber composition>

The rubber composition of the present invention is characterized in that it includes a rubber component including the acrylic rubber, a filler, and a crosslinking agent.

As the rubber component serving as the main component of the rubber composition of the present invention, the acrylic rubber of the present invention may be used alone or, if necessary, may be used in combination with the acrylic rubber of the present invention and other rubber components. The content of the acrylic rubber of the present invention in the rubber component may be selected according to the purpose of use, and is, for example, usually 30% by weight or more, preferably 50% by weight or more, and more preferably 70% by weight or more.

The other rubber component to be combined with the acrylic rubber of the present invention is not particularly limited, and examples thereof include natural rubber, polybutadiene rubber, polyisoprene rubber, styrene-butadiene rubber, acrylonitrile-butadiene rubber, silicone rubber, and fluororubber, olefin-based elastomers, styrene-based elastomers, vinyl chloride-based elastomers, polyester-based elastomers, polyamide-based elastomers, polyurethane-based elastomers, and polysiloxane-based elastomers.

These other rubber components can be used alone or in combination of two or more. The shape of these other rubber components may be crumb, strand, veil, sheet, or powder. The content of the other rubber components in the entire rubber component is appropriately selected within a range that does not impair the effects of the present invention, and is, for example, usually 70% by weight or less, preferably 50% by weight or less, more preferably 30% by weight or less.

The filler included in the rubber composition is not particularly limited, but examples thereof include reinforcing fillers and non-reinforcing fillers. Preferably, when the reinforcing filler is used, roll processability of the rubber composition, Banbury processability and short-time It is suitable because it has excellent crosslinkability and highly excellent water resistance, strength characteristics and compression set resistance of the crosslinked product.

Examples of reinforcing fillers include carbon blacks such as furnace black, acetylene black, thermal black, channel black and graphite; silicas such as wet silica, dry silica, and colloidal silica; etc. can be mentioned. Non-reinforcing fillers include quartz powder, diatomaceous earth, zinc oxide, basic magnesium carbonate, activated calcium carbonate, magnesium silicate, aluminum silicate, titanium dioxide, talc, aluminum sulfate, calcium sulfate, barium sulfate and the like.

These fillers can be used individually or in combination of two or more, and the blending amount thereof is appropriately selected within a range that does not impair the effect of the present invention, and is usually 1 to 200 parts by weight based on 100 parts by weight of the rubber component. part, preferably 10 to 150 parts by weight, more preferably 20 to 100 parts by weight.

The crosslinking agent used in the rubber composition is not particularly limited, and conventionally known crosslinking agents are selected depending on the purpose of use, and examples thereof include inorganic crosslinking agents such as sulfur compounds and organic crosslinking agents, preferably organic crosslinking agents. . The crosslinking agent may be either a polyvalent compound or a monovalent compound, but a polyvalent compound having two or more reactive groups is preferable. The crosslinking agent may be any of an ion crosslinkable compound or a radical crosslinkable compound, but is preferably an ion crosslinkable compound.

The organic crosslinking agent is not particularly limited, but an ionic crosslinkable organic compound is preferred, and a polyvalent ion organic compound is particularly preferred. When the crosslinking agent is a multivalent ion organic compound (polyvalent ion crosslinkable compound), the rubber composition has excellent roll processability, Banbury processability and crosslinkability in a short time, and also has highly excellent strength characteristics and compression set resistance of the crosslinked product. Since it is also excellent in water resistance, it is particularly suitable. The "ion" of the ion crosslinkable or polyvalent ion is not particularly limited as long as it is an ion reactive ion, for example, an ion reactive group of the ion reactive group-containing monomer of the above acrylic rubber, but preferably amine ion-crosslinkable organic compounds having ion-reactive groups such as groups, epoxy groups, carboxyl groups, and thiol groups.

Specific examples of the polyvalent ion organic compound include polyvalent amine compounds, polyvalent epoxy compounds, polyvalent carboxylic acid compounds, and polyvalent thiol compounds, preferably polyvalent amine compounds and polyvalent thiol compounds, more preferably polyvalent amines. it is a compound

Examples of the polyhydric amine compound include aliphatic polyhydric amine compounds such as hexamethylenediamine, hexamethylenediamine carbamate, and N,N'-dicinnamylidene-1,6-hexanediamine; 4,4'-methylenedianiline, p-phenylenediamine, m-phenylenediamine, 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-(m -Phenylenediisopropylidene)dianiline, 4,4'-(p-phenylenediisopropylidene)dianiline, 2,2'-bis[4-(4-aminophenoxy)phenyl]propane, 4,4 Aromatic polyvalent compounds such as '-diaminobenzanilide, 4,4'-bis(4-aminophenoxy)biphenyl, m-xylylenediamine, p-xylylenediamine, and 1,3,5-benzenetriamine amine compounds; etc. can be mentioned. Among these, hexamethylenediamine carbamate, 2,2'-bis[4-(4-aminophenoxy)phenyl]propane, etc. are preferable. As a polyhydric amine compound, these carbonate salts can also be used conveniently. These polyhydric amine compounds are particularly preferably used in combination with a carboxyl group-containing acrylic rubber or an epoxy group-containing acrylic rubber.

As the polyvalent thiol compound, a triazine thiol compound is preferably used, for example, 6-trimercapto-s-triazine, 2-anilino-4,6-dithiol-s-triazine, 1 -Dibutylamino-3,5-dimercaptotriazine, 2-dibutylamino-4,6-dithiol-s-triazine, 1-phenylamino-3,5-dimercaptotriazine, 2,4,6-trimercapto-1,3,5-triazine, 1-hexylamino-3,5-dimercaptotriazine, etc. are mentioned. These triazinethiol compounds are particularly preferably used in combination with chlorine atom-containing acrylic rubber.

Examples of other polyvalent organic compounds include polyvalent carboxylic acid compounds such as tetradecanedioic acid, and dithiocarbamic acid metal salts such as zinc dimethyldithiocarbamate. These other polyvalent organic compounds are particularly suitably used in combination with an epoxy group-containing acrylic rubber.

These crosslinking agents can be used individually or in combination of two or more, and the compounding amount is usually 0.001 to 20 parts by weight, preferably 0.1 to 10 parts by weight, more preferably 0.1 to 100 parts by weight of the rubber component. ~5 parts by weight. By making the compounding quantity of a crosslinking agent into this range, it is suitable because it can make it excellent in mechanical strength as a rubber crosslinked material, making rubber elasticity sufficient.

In the rubber composition of the present invention, an anti-aging agent may be incorporated as needed. The type of anti-aging agent is not particularly limited, and examples thereof include 2,6-di-t-butyl-4-methylphenol, 2,6-di-t-butylphenol, butylhydroxyanisole, and 2,6-di-t-butyl-4-methylphenol. -Di-t-butyl-α-dimethylamino-p-cresol, octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, styrenated phenol, 2,2' -Methylene-bis(6-α-methyl-benzyl-p-cresol), 4,4'-methylenebis(2,6-di-t-butylphenol), 2,2'-methylene-bis(4-methyl -6-t-butylphenol), 2,4-bis[(octylthio)methyl]-6-methylphenol, 2,2'-thiobis-(4-methyl-6-t-butylphenol), 4, 4'-thiobis-(6-t-butyl-o-cresol), 2,6-di-t-butyl-4-(4,6-bis(octylthio)-1,3,5-triazine- other phenolic antioxidants such as 2-ylamino)phenol; phosphite ester anti-aging agents such as tris(nonylphenyl)phosphite, diphenyl isodecyl phosphite, and tetraphenyldipropylene glycol diphosphite; sulfur ester-based anti-aging agents such as dilauryl thiodipropionate; Phenyl-α-naphthylamine, phenyl-β-naphthylamine, p-(p-toluenesulfonylamide)-diphenylamine, 4,4′-(α,α-dimethylbenzyl)diphenylamine, N, amine anti-aging agents such as N-diphenyl-p-phenylenediamine, N-isopropyl-N'-phenyl-p-phenylenediamine, and butyraldehyde-aniline condensates; imidazole-based anti-aging agents such as 2-mercaptobenzimidazole; quinoline anti-aging agents such as 6-ethoxy-2,2,4-trimethyl-1,2-dihydroquinoline; hydroquinone-based anti-aging agents such as 2,5-di-(t-amyl)hydroquinone; etc. can be mentioned. Among these, an amine-type anti-aging agent is especially preferable.

These antioxidants can be used individually or in combination of two or more, and the compounding amount is 0.01 to 15 parts by weight, preferably 0.1 to 10 parts by weight, more preferably 0.1 to 10 parts by weight, based on 100 parts by weight of the rubber component. It is in the range of 1 to 5 parts by weight.

The rubber composition of the present invention includes the rubber component including the acrylic rubber of the present invention, a filler and a crosslinking agent as essential components, and optionally an anti-aging agent, and, if necessary, other components commonly used in the art. Additives such as crosslinking aids, crosslinking accelerators, crosslinking retardants, silane coupling agents, plasticizers, processing aids, lubricants, pigments, colorants, antistatic agents, foaming agents and the like can be optionally blended. These other compounding agents can be used individually or in combination of two or more types, respectively, and the compounding amount is appropriately selected within a range not impairing the effect of the present invention.

As a method for producing the rubber composition of the present invention, a method of mixing a rubber component containing the acrylic rubber of the present invention, a filler, a crosslinking agent, and an anti-aging agent and other compounding agents that may be contained as necessary may be mentioned, and mixing For this, any means used in the conventional rubber processing field, for example, open rolls, Banbury mixers, various types of kneaders, and the like can be used. The mixing order of each component may be carried out according to the usual procedure used in the field of rubber processing. For example, after sufficiently mixing components that are difficult to react or decompose by heat, a crosslinking agent, which is a component that is easily reacted or decomposed by heat, etc. It is preferable to mix in a short time at a temperature at which no reaction or decomposition occurs.

<Crosslinked Rubber>

The crosslinked rubber product of the present invention is formed by crosslinking the above rubber composition.

The crosslinked rubber product of the present invention is molded using the rubber composition of the present invention with a molding machine corresponding to a desired shape, such as an extruder, injection molding machine, compressor or roll, and subjected to a crosslinking reaction by heating, and rubber It can be manufactured by fixing the shape as a cross-linked product. In this case, crosslinking may be performed after molding in advance, or crosslinking may be performed simultaneously with molding. The molding temperature is usually 10 to 200°C, preferably 25 to 150°C. The crosslinking temperature is usually 100 to 250°C, preferably 130 to 220°C, more preferably 150 to 200°C, and the crosslinking time is usually 0.1 minute to 10 hours, preferably 1 minute to 5 hours. As the heating method, methods used for crosslinking rubber such as press heating, steam heating, oven heating, and hot air heating may be appropriately selected.

The cross-linked rubber of the present invention may be subjected to secondary cross-linking by further heating depending on the shape, size and the like of the cross-linked rubber. Secondary crosslinking varies depending on the heating method, crosslinking temperature, shape, etc., but is preferably carried out for 1 to 48 hours. What is necessary is just to select a heating method and a heating temperature suitably.

The crosslinked rubber of the present invention has excellent compression set resistance and water resistance while maintaining the basic properties of rubber such as tensile strength, elongation and hardness.

The rubber crosslinked product of the present invention takes advantage of the above characteristics and, for example, O-rings, packings, diaphragms, oil seals, shaft seals, bearing seals, mechanical seals, wellhead seals, seals for electrical and electronic equipment, air compression sealing materials such as seals for instruments; A rocker cover gasket attached to the connection between the cylinder block and the cylinder head, an oil pan gasket attached to the connection between the oil pan and the cylinder head or transmission case, and between a pair of housings that insert the unit cell having the positive electrode, the electrolyte plate, and the negative electrode. various gaskets such as gaskets for fuel cell separators and gaskets for top covers of hard disk drives; buffer material, anti-vibration material; wire covering materials; industrial belts; tubes and hoses; sheets; etc. are used suitably.

The crosslinked rubber product of the present invention is also an extrusion molded article and molded crosslinked product used for automobile applications, for example, fuel hoses, filler neck hoses, vent hoses, paper hoses, fuel tanks such as oil hoses, etc. It is suitably used for various hoses such as oil-based hoses, turbo air hoses, air-type hoses such as mission control hoses, radiator hoses, heater hoses, brake hoses, and air-conditioner hoses.

<Equipment configuration used for production of acrylic rubber>

Next, the configuration of an apparatus used for producing acrylic rubber according to an embodiment of the present invention will be described. 1 is a diagram schematically showing an example of an acrylic rubber production system having a device configuration used for production of acrylic rubber according to an embodiment of the present invention. For the production of acrylic rubber according to the present invention, the acrylic rubber production system 1 shown in FIG. 1 can be used, for example.

The acrylic rubber manufacturing system 1 shown in FIG. 1 is constituted by an emulsion polymerization reactor, a coagulation device 3, a washing device 4, a moisture remover 43, and a screw-type twin-screw extrusion dryer (not shown).

The emulsion polymerization reactor is configured to perform processing related to the emulsion polymerization step described above. Although not shown in FIG. 1, this emulsion polymerization reactor has, for example, a polymerization reactor, a temperature control unit for controlling the reaction temperature, a motor, and an agitator equipped with agitating blades. In the emulsion polymerization reactor, monomer components for forming acrylic rubber are mixed with water and an emulsifier, emulsified while appropriately stirred with a stirrer, and an emulsion polymerization reaction is initiated in the presence of a redox catalyst composed of an inorganic radical generator and a reducing agent, An emulsion polymerization solution may be obtained by post-adding a chain transfer agent batchwise during the polymerization. The emulsion polymerization reactor may be any of a batch type, semi-batch type and continuous type, and may be either a tank type reactor or a tubular type reactor.

The solidification device 3 shown in FIG. 1 is configured to perform processing related to the above-described solidification step. As schematically shown in FIG. 1 , the coagulation device 3 includes, for example, a stirring tank 30, a heating unit 31 for heating the inside of the stirring tank 30, and the temperature inside the stirring tank 30. It has a drive control unit (not shown) that controls the temperature controller (not shown), the stirring device 34 provided with the motor 32 and the stirring blades 33, and the number of revolutions and rotational speed of the stirring blades 33. In the coagulation device 3, the emulsion polymerization liquid obtained in the emulsion polymerization reactor is brought into contact with the coagulation liquid to solidify, whereby a water-containing crumb can be produced.

In the coagulation device 3, for example, a method of adding the emulsion polymerization solution to the stirring coagulation solution is employed for the contact between the emulsion polymerization solution and the coagulation solution. That is, a water-containing crumb is produced by filling the stirring tank 30 of the coagulation device 3 with a coagulating liquid, adding and bringing the emulsion polymerization liquid into contact with the coagulating liquid to solidify the emulsion polymerization liquid.

The heating unit 31 of the coagulation device 3 is configured to heat the coagulating liquid filled in the stirring vessel 30 . In addition, the temperature control unit of the coagulation device 3 is configured to control the temperature in the stirring vessel 30 by controlling the heating operation by the heating unit 31 while monitoring the temperature in the stirring vessel 30 measured with a thermometer. has been The temperature of the coagulating liquid in the stirring vessel 30 is controlled by the temperature control unit so as to be in the range of usually 40°C or higher, preferably 40 to 90°C, and more preferably 50 to 80°C.

The stirring device 34 of the coagulation device 3 is configured to stir the coagulating liquid filled in the stirring tank 30 . Specifically, the stirring device 34 includes a motor 32 that generates rotational power, and a stirring blade 33 that extends in a vertical direction with respect to the rotating shaft of the motor 32 . The agitating blade 33 can cause the coagulating liquid to flow by rotating centering on the rotating shaft by the rotational power of the motor 32 within the coagulating liquid filled in the stirring tank 30 . The shape and size of the stirring blades 33, the number of installations, and the like are not particularly limited.

The driving control unit of the coagulation device 3 controls the rotation drive of the motor 32 of the stirring device 34 to set the number of rotations and the rotational speed of the stirring blades 33 of the stirring device 34 to predetermined values. Consists of. The stirring rate of the coagulating solution is, for example, usually 100 rpm or more, preferably 200 to 1000 rpm, more preferably 300 to 900 rpm, particularly preferably 400 to 800 rpm, and stirred by the driving control unit. Rotation of the wing 33 is controlled. The circumferential velocity of the coagulating solution is usually 0.5 m/s or more, preferably 1 m/s or more, more preferably 1.5 m/s or more, particularly preferably 2 m/s or more, and most preferably 2.5 m/s or more. The rotation of the stirring blade 33 is controlled by the drive control unit so that it becomes s or more. In addition, the drive is such that the upper limit of the circumferential speed of the coagulating liquid is usually 50 m/s or less, preferably 30 m/s or less, more preferably 25 m/s or less, and most preferably 20 m/s or less. Rotation of the agitation blade 33 is controlled by the control unit.

The cleaning device 4 shown in FIG. 1 is configured to perform processing related to the cleaning process described above. As schematically shown in FIG. 1 , the washing device 4 includes, for example, a washing tank 40, a heating unit 41 for heating the inside of the washing tank 40, and a temperature inside the washing tank 40. It has a temperature controller (not shown) that controls the temperature. In the cleaning device 4, the amount of ash content in the finally obtained acrylic rubber can be effectively reduced by mixing the hydrous crumb produced in the coagulation device 3 with a large amount of water for washing.

The heating unit 41 of the cleaning device 4 is configured to heat the inside of the cleaning tank 40 . In addition, the temperature controller of the cleaning device 4 controls the heating operation by the heating unit 41 while monitoring the temperature inside the cleaning tub 40 measured by a thermometer, thereby controlling the temperature inside the cleaning tub 40. has been As described above, the temperature of the washing water in the washing tank 40 is usually 40°C or higher, preferably 40 to 100°C, more preferably 50 to 90°C, and most preferably 60 to 80°C. controlled so that

The water-containing crumb washed in the washing device 4 is supplied to the screw-type twin-screw extrusion dryer 5 that performs a dewatering step and a drying step. At this time, it is preferable that the water-containing crumb after washing is supplied to the screw-type twin-screw extrusion dryer 5 through a moisture remover 43 capable of separating free water. For the moisture remover 43, for example, a wire mesh, a screen, a rolling element, etc. can be used.

In addition, when the water-containing crumb after washing is supplied to the screw-type twin-screw extrusion dryer 5, the temperature of the water-containing crumb is preferably 40°C or higher, more preferably 60°C or higher. For example, the temperature of the water-containing crumb when supplied to the screw type twin-screw extrusion dryer 5 by setting the temperature of water used for washing with water in the washing device 4 to 60°C or higher (for example, 70°C). It may be maintained at 60 ° C. or higher, or it may be heated so that the temperature of the hydrous crumb is 40 ° C. or higher, preferably 60 ° C. or higher when conveying from the cleaning device 4 to the screw type twin screw extrusion dryer 5. . This makes it possible to effectively carry out the dewatering step and the drying step, which are the subsequent steps, and it becomes possible to significantly reduce the moisture content of the finally obtained dried rubber.

The screw-type twin-screw extrusion dryer 5 shown in FIG. 1 is configured to perform processing related to the dehydration step and the drying step described above. On the other hand, although a screw type twin screw extrusion dryer 5 is shown as a suitable example in FIG. 1, a centrifugal separator, a squeezer, etc. may be used as a dewatering machine for performing treatment related to the dehydration step, and to perform treatment related to the drying step As a dryer, you may use a hot air dryer, a vacuum dryer, an expander dryer, a kneader type dryer, etc.

The screw-type twin-screw extrusion dryer 5 is configured to mold and discharge dried rubber obtained through a dehydration step and a drying step into a predetermined shape. Specifically, the screw-type twin-screw extrusion dryer 5 has a dewatering barrel part 53 functioning as a dewatering machine for dewatering the water-containing crumb washed in the cleaning device 4 and a dryer function for drying the water-containing crumb. It is equipped with a drying barrel part 54, and furthermore, it is configured by providing a die 59 having a molding function for forming hydrous crumbs on the downstream side of the screw-type twin screw extrusion dryer 5.

Hereinafter, the structure of the screw type twin screw extrusion dryer 5 is demonstrated, referring FIG. FIG. 2 shows the configuration of a specific example suitable for the screw type twin screw extrusion dryer 5 shown in FIG. 1 . With this screw-type twin-screw extrusion dryer 5, the above-described dehydration and drying steps can be suitably performed.

The screw-type twin-screw extrusion dryer 5 shown in FIG. 2 is a twin-screw type extrusion dryer comprising a pair of screws (not shown) in a barrel unit 51 . The screw-type twin-screw extrusion dryer 5 has a drive unit 50 that rotationally drives a pair of screws in a barrel unit 51 . With this structure, high shear can be applied to acrylic rubber and drying can be performed, which is suitable. The drive unit 50 is attached to the upstream end of the barrel unit 51 (the left end in FIG. 2 ). Further, the screw-type twin screw extrusion dryer 5 has a die 59 at the downstream end of the barrel unit 51 (right end in FIG. 2 ).

The barrel unit 51 has a supply barrel part 52, a dewatering barrel part 53, and a drying barrel part 54 from the upstream side to the downstream side (left to right in FIG. 2).

The supply barrel part 52 is comprised by two supply barrels, ie, the 1st supply barrel 52a and the 2nd supply barrel 52b.

In addition, the dewatering barrel part 53 is constituted by three dewatering barrels, that is, the first dewatering barrel 53a, the second dewatering barrel 53b, and the third dewatering barrel 53c.

In addition, the drying barrel portion 54 includes eight drying barrels, that is, a first drying barrel 54a, a second drying barrel 54b, a third drying barrel 54c, a fourth drying barrel 54d, and a second drying barrel 54b. It is comprised by the 5th dry barrel 54e, the 6th dry barrel 54f, the 7th dry barrel 54g, and the 8th dry barrel 54h.

In this way, the barrel unit 51 is configured by connecting each of the 13 divided barrels 52a to 52b, 53a to 53c, and 54a to 54h from the upstream side to the downstream side.

In addition, the screw-type twin-screw extrusion dryer 5 individually heats each of the barrels 52a to 52b, 53a to 53c, and 54a to 54h, so that each barrel 52a to 52b, 53a to 53c, and 54a to 54h It has a heating means (not shown) that heats the water-containing crumbs inside to a predetermined temperature. Heating means is equipped with the number corresponding to each barrel 52a-52b, 53a-53c, and 54a-54h. As such a heating means, for example, a configuration in which high-temperature steam is supplied from a steam supply means to a steam distribution jacket formed in each of the barrels 52a to 52b, 53a to 53c, and 54a to 54h is employed. It doesn't work. In addition, the screw-type twin-screw extrusion dryer 5 has temperature control means (not shown) that controls the set temperature of each heating means corresponding to each of the barrels 52a to 52b, 53a to 53c, and 54a to 54h.

On the other hand, the number of supply barrels, dewatering barrels, and drying barrels constituting each of the barrel parts 52, 53, and 54 in the barrel unit 51 is not limited to the embodiment shown in FIG. 2, and the drying process It can be set to a number according to the water content of the water-containing crumb of the acrylic rubber.

For example, the number of installation of the supply barrel of the supply barrel part 52 becomes 1-3, for example. In addition, the number of dewatering barrels installed in the dewatering barrel part 53 is preferably 2 to 10, for example, and 3 to 6 is more preferable because dehydration of the water-containing crumb of the adhesive acrylic rubber can be efficiently performed. . Moreover, the number of dry barrels installed in the dry barrel part 54 is preferably 2 to 10, for example, and more preferably 3 to 8.

The pair of screws in the barrel unit 51 are rotationally driven by drive means such as a motor housed in the drive unit 50 . The pair of screws extend from the upstream side to the downstream side in the barrel unit 51, and by being driven to rotate, the water-containing crumb supplied to the supply barrel portion 52 can be conveyed to the downstream side while mixing. there is to be The pair of screws are preferably of a biaxially engaged type in which the ridge and valley portions are engaged with each other, whereby the dewatering efficiency and drying efficiency of the hydrous crumb can be increased.

Further, the rotational directions of the pair of screws may be the same or different, but from the viewpoint of self-cleaning performance, it is preferable that they rotate in the same direction. The screw shape of the pair of screws is not particularly limited, and any shape required for each of the barrel portions 52, 53, and 54 is sufficient and is not particularly limited.

The supply barrel portion 52 is an area for supplying water-containing crumbs into the barrel unit 51 . The 1st supply barrel 52a of the supply barrel part 52 has the feed opening 55 which supplies water-containing crumbs into the barrel unit 51.

The dewatering barrel part 53 is an area that separates and discharges a liquid (serum water) containing a coagulant or the like from the water-containing crumbs.

The first to third dewatering barrels 53a to 53c constituting the dewatering barrel part 53 each have dewatering slits 56a, 56b, and 56c for discharging moisture in the water-containing crumb to the outside. A plurality of dewatering slits 56a, 56b, and 56c are formed in each of the dewatering barrels 53a to 53c, respectively.

The slit width of each dewatering slit (56a, 56b, 56c), that is, the size of the eye, may be appropriately selected according to the conditions of use, and is usually 0.01 to 5 mm, with little loss of hydrous crumbs and efficient dewatering of the hydrous crumbs. From the viewpoint of being able to do it, it is preferably 0.1 to 1 mm, more preferably 0.2 to 0.6 mm.

Removal of water from the water-containing crumbs in each dewatering barrel 53a to 53c of the dewatering barrel part 53 is carried out in a liquid phase from each of the dewatering slits 56a, 56b, and 56c, and in a vapor phase. There are two cases of doing so. In the dewatering barrel part 53 of the present embodiment, the case where water is removed in the liquid phase is defined as drainage, and the case where water is removed in the vapor phase is defined as double steam.

In the dewatering barrel part 53, since it is possible to efficiently reduce the water content of the adhesive acrylic rubber by combining drainage and steam removal, it is suitable. In the dewatering barrel part 53, which dewatering barrel among the first to third dewatering barrels 53a to 53c is used to drain or double steam may be appropriately set depending on the purpose of use. In the case of reducing the amount, the number of dewatering barrels for draining water may be increased. In that case, for example, as shown in FIG. 2 , drainage is performed by the first and second dewatering barrels 53a and 53b on the upstream side, and steam is doubled by the third dewatering barrel 53c on the downstream side. Further, for example, when the dewatering barrel part 53 has four dewatering barrels, for example, three dewatering barrels on the upstream side drain water, and one dewatering barrel on the downstream side performs steam doubling. can think of On the other hand, when reducing the water content, it is good to increase the number of dewatering barrels for doubling steam.

The set temperature of the dewatering barrel part 53 is usually in the range of 60 to 150°C, preferably 70 to 140°C, and more preferably 80 to 130°C, as described in the above-mentioned dewatering/drying step. The set temperature of the dewatering barrel for dehydration in the state is usually 60 to 120 ° C, preferably 70 to 110 ° C, more preferably 80 to 100 ° C, and the set temperature of the dehydration barrel for dehydration in the double steam state is usually 100 ° C. to 150°C, preferably 105 to 140°C, more preferably 110 to 130°C.

The drying barrel part 54 is a region for drying the dehydrated crumbs under reduced pressure. Of the first to eighth drying barrels 54a to 54h constituting the drying barrel part 54, the second drying barrel 54b, the fourth drying barrel 54d, the sixth drying barrel 54f, and the eighth drying barrel 54b. The barrel 54h has vent ports 58a, 58b, 58c, and 58d for degassing, respectively. Vent pipes (not shown) are respectively connected to the respective vent ports 58a, 58b, 58c, and 58d.

A vacuum pump (not shown) is connected to the end of each vent pipe, and the inside of the drying barrel part 54 is reduced to a predetermined pressure by the operation of the vacuum pump. The screw-type extruder 5 has a pressure control unit (not shown) that controls the degree of pressure reduction in the drying barrel part 54 by controlling the operation of these vacuum pumps.

The pressure reduction degree in the drying barrel part 54 may be appropriately selected, but as described above, it is usually set to 1 to 50 kPa, preferably 2 to 30 kPa, and more preferably 3 to 20 kPa.

In addition, the set temperature in the drying barrel part 54 may be appropriately selected, but as described above, it is usually set to 100 to 250°C, preferably 110 to 200°C, and more preferably 120 to 180°C.

In each of the drying barrels 54a to 54h constituting the drying barrel portion 54, the set temperature in all the drying barrels 54a to 54h may be approximated or different, but the upstream side (dewatering barrel portion 53 It is preferable to set the temperature on the downstream side (die 59 side) to a higher temperature than the temperature on the ) side) because the drying efficiency is improved.

The die 59 is a mold disposed at the downstream end of the barrel unit 51 and has a discharge port having a predetermined nozzle shape. Acrylic rubber dried in the drying barrel part 54 is extruded into a shape according to a predetermined nozzle shape by passing through the discharge port of the die 59 . The acrylic rubber passing through the die 59 can be molded into various shapes such as particulate, columnar, round rod, and sheet shapes depending on the nozzle shape of the die 59, but in the present invention, it is molded into a sheet shape. . Between the screw and the die 59, a breaker plate or wire mesh may or may not be provided.

The hydrous crumb of acrylic rubber obtained through the washing process is supplied to the supply barrel part 52 from the feed port 55 . The water-containing crumb supplied to the supply barrel part 52 is sent from the supply barrel part 52 to the dewatering barrel part 53 by rotation of a pair of screws in the barrel unit 51 . In the dewatering barrel part 53, as described above, drainage or double steam of moisture contained in the water-containing crumbs is discharged from the dewatering slits 56a, 56b, and 56c provided in the first to third dewatering barrels 53a to 53c, respectively. As a result, the water-containing crumb is dehydrated.

The water-containing crumb dewatered in the dewatering barrel part 53 is sent to the drying barrel part 54 by the rotation of a pair of screws in the barrel unit 51 . The water-containing crumb sent to the drying barrel part 54 is plasticized and mixed to become a melt, and is transported downstream while generating heat and raising the temperature. Then, the moisture contained in the acrylic rubber melt is vaporized, and the moisture (steam) is discharged to the outside through vent pipes (not shown) connected to the respective vent ports 58a, 58b, 58c, and 58d, respectively.

As described above, by passing through the drying barrel part 54, the water-containing crumb is dried and becomes a melt of acrylic rubber, and the acrylic rubber is supplied to the die 59 by the rotation of a pair of screws in the barrel unit 51, extruded from die 59.

Here, an example of the operating conditions of the screw-type twin-screw extrusion dryer 5 according to the present embodiment is given.

The number of rotations (N) of the pair of screws in the barrel unit 51 may be appropriately selected depending on various conditions, and is usually 10 to 1000 rpm, effectively reducing the water content of acrylic rubber and the amount of methyl ethyl ketone insoluble. From the point which can reduce, Preferably it is 50-750 rpm, More preferably, it is 100-500 rpm, and 120-300 rpm is the most preferable.

In addition, the extrusion amount (Q) of the acrylic rubber is not particularly limited, but is usually 100 to 1500 kg/hr, preferably 300 to 1200 kg/hr, more preferably 400 to 1000 kg/hr, 500 to 800 kg/hr is most preferred.

The ratio (Q/N) of the amount of extrusion (Q) of the acrylic rubber and the number of revolutions (N) of the screw (Q/N) is not particularly limited, but is usually 1 to 20, preferably 2 to 10, more preferably 3 to 8, and 4 to 6 are particularly preferred.

The maximum torque in the barrel unit 51 is not particularly limited, but is usually in the range of 30 to 100 N·m, preferably 35 to 75 N·m, and more preferably 40 to 60 N·m.

The specific power in the barrel unit 51 is not particularly limited, but is usually 0.1 to 0.25 [kw h/kg] or more, preferably 0.13 to 0.23 [kw h/kg], more preferably 0.15 to 0.2 [kw h/kg]. kw·h/kg].

The specific power in the barrel unit 51 is not particularly limited, but is usually 0.2 to 0.6 [A h/kg] or more, preferably 0.25 to 0.55 [A h/kg], more preferably 0.35 to 0.5 [A h/kg]. A h/kg].

The shear rate in the barrel unit 51 is not particularly limited, but is usually 40 to 150 [1/s] or more, preferably 45 to 125 [1/s], more preferably 50 to 100 [1/s]. is the range of

The shear viscosity of the acrylic rubber in the barrel unit 51 is not particularly limited, but is usually 4000 to 8000 [Pa s] or less, preferably 4500 to 7500 [Pa s], more preferably 5000 to 7000 [Pa s]. s] range.

The cooling device 6 shown in FIG. 1 is configured to cool dry rubber obtained through a dehydration step by a dehydrator and a drying step by a dryer. As a cooling method by the cooling device 6, it is possible to adopt various methods including an air cooling method under blowing or air conditioning, a splashing method in which water is sprayed, an immersion method in which water is immersed, and the like. Alternatively, the dried rubber may be cooled by leaving it at room temperature.

As described above, depending on the nozzle shape of the die 59, the dry rubber discharged from the screw extruder 5 is extruded into various shapes such as particulate, columnar, round bar, and sheet shapes. In the case, it is molded into a sheet shape. Hereinafter, referring to FIG. 3, as an example of the cooling device 6, a transport type cooling device 60 that cools the sheet-shaped dry rubber 10 molded into a sheet shape will be described.

FIG. 3 shows the configuration of a transport type cooling device 60 suitable as the cooling device 6 shown in FIG. 1 . The conveying type cooling device 60 shown in FIG. 3 is configured to cool the sheet-shaped dry rubber 10 discharged from the discharge port of the die 59 of the screw extruder 5 by an air cooling method while conveying it. By using this transport type cooling device 60, the sheet-shaped dry rubber discharged from the screw extruder 5 can be appropriately cooled.

The transport type cooling device 60 shown in FIG. 3 is directly connected to the die 59 of the screw type extruder 5 shown in FIG. 2, or installed near the die 59 and used, for example.

The conveying type cooling device 60 includes a conveyor 61 for conveying the sheet-shaped dry rubber 10 discharged from the die 59 of the screw extruder 5 in the direction of arrow A in FIG. 3, and the conveyor 61 ) has a cooling means 65 for blowing cold air to the sheet-shaped dry rubber 10.

The conveyor 61 has rollers 62 and 63 and a conveyor belt 64 that is wound around the rollers 62 and 63 and on which the sheet-shaped dry rubber 10 is placed. The conveyor 61 is configured to continuously convey the sheet-shaped dry rubber 10 discharged from the die 59 of the screw extruder 5 on the conveyor belt 64 to the downstream side (right side in FIG. 3). there is.

The cooling means 65 is not particularly limited, but is configured to, for example, blow cooling air sent from a cooling air generating means (not shown) onto the surface of the sheet-shaped dry rubber 10 on the conveyor belt 64. Having a , etc. can be mentioned.

The length of the conveyor 61 and the cooling means 65 of the transport type cooling device 60 (the length of the portion where the cooling wind can be blown) L1 is not particularly limited, but is, for example, 10 to 100 m, preferably. is between 20 and 50 m. In addition, the conveyance speed of the sheet-shaped dry rubber 10 in the conveying type cooling device 60 is the length L1 of the conveyor 61 and the cooling means 65 and the die 59 of the screw extruder 5 It may be appropriately adjusted according to the discharge rate of the sheet-shaped dry rubber 10 discharged from the , the target cooling rate or cooling time, for example, 10 to 100 m/hr, more preferably 15 to 70 m/hr. am.

According to the transport type cooling device 60 shown in FIG. 3 , while conveying the sheet-like dry rubber 10 discharged from the die 59 of the screw extruder 5 by the conveyor 61, the sheet-like dry rubber 10 The sheet-shaped dry rubber 10 is cooled by blowing cooling air from the cooling means 65 to the .

On the other hand, the conveying type cooling device 60 is not particularly limited to a configuration including one conveyor 61 and one cooling means 65 as shown in FIG. 3, and two or more conveyors 61 and this It is good also as a structure provided with the corresponding two or more cooling means 65. In that case, each total length of the two or more conveyors 61 and the cooling means 65 may be within the above range.

The baling device 7 shown in FIG. 1 is configured to process dry rubber extruded from a screw extruder 5 and cooled in a cooling device 6 to produce a bale, which is a block. . As described above, the screw extruder 5 can extrude dry rubber into various shapes such as particulate, columnar, round bar, and sheet shapes, and the baling device 7 has various shapes in this way. It is configured to bale the molded dry rubber. Although the weight, shape, etc. of the veiled acrylic rubber produced by the baling device 7 are not particularly limited, for example, about 20 kg of substantially rectangular parallelepiped veiled acrylic rubber is produced.

The baling device 7 may be provided with a baler, for example, and may manufacture the bale-like acrylic rubber by compressing the cooled dry rubber with the baler.

In addition, when the sheet-like dry rubber 10 is manufactured by the screw extruder 5, you may manufacture the veil-like acrylic rubber in which the sheet-like dry rubber 10 was laminated|stacked. For example, a cutting mechanism for cutting the sheet-shaped dry rubber 10 may be installed in the baling device 7 arranged on the downstream side of the transport type cooling device 60 shown in FIG. 3 . Specifically, the cutting mechanism of the baling device 7 continuously cuts the cooled sheet-like dry rubber 10 at predetermined intervals, for example, to cut sheet-like dry rubber 16 of a predetermined size. It is configured to be processed into. By laminating a plurality of sheets of cut sheet-shaped dry rubber 16 cut into a predetermined size by a cutting mechanism, a veil-like acrylic rubber in which cut sheet-shaped dry rubber 16 is laminated can be produced.

In the case of producing a veil-like acrylic rubber in which the cut sheet-like dry rubber 16 is laminated, it is preferable to laminate the cut sheet-like dry rubber 16 at 40°C or higher, for example. By laminating the cut sheet-like dry rubber 16 at 40°C or higher, good air bleeding is realized by additional cooling and compression by its own weight.

Example

Below, examples and comparative examples will be given to explain the present invention in more detail. "Part", "%" and "ratio" in each case are based on weight unless otherwise specified. On the other hand, various physical properties were evaluated according to the following methods.

[monomer composition]

Regarding the monomer composition of the acrylic rubber, the monomer constitution of each monomer unit in the acrylic rubber was confirmed by ¹ H-NMR, and the activity of the reactive group remaining in the acrylic rubber and the content of each reactive group were determined by the following method. Confirmed. In addition, the content ratio of each monomeric unit in acrylic rubber was computed from the usage-amount and polymerization conversion ratio used for the polymerization reaction of each monomer. Specifically, the polymerization reaction was an emulsion polymerization reaction, and since the polymerization conversion rate was approximately 100%, which could not confirm any unreacted monomers, the content ratio of each monomer unit in the rubber was the same as the amount of each monomer used. .

[Reactive group content]

Content of the reactive group in acrylic rubber was measured by the following method.

(1) The amount of carboxyl groups was calculated by dissolving a sample (acrylic rubber) in acetone and performing potentiometric titration with a potassium hydroxide solution.

(2) The amount of epoxy groups was calculated by dissolving a sample in methyl ethyl ketone, adding a prescribed amount of hydrochloric acid thereto to react with epoxy groups, and titrating the remaining amount of hydrochloric acid with potassium hydroxide.

(3) The amount of chlorine was calculated by completely burning a sample in a combustion flask, absorbing generated chlorine into water, and titrating with silver nitrate.

[Ashes amount]

The ash content (%) contained in the acrylic rubber was measured according to JIS K6228 A method.

[Ashes component amount]

The amount (ppm) of each component in the acrylic rubber ash was measured by XRF using ZSX Primus (manufactured by Rigaku) by pressing the ash collected at the time of measuring the ash amount above with a suitable filter paper of φ 20 mm.

[Molecular weight and molecular weight distribution]

The weight average molecular weight (Mw) and molecular weight distribution (Mw/Mn and Mz/Mw) of acrylic rubber were obtained from a solution in which 0.05 mol/L of lithium chloride and 0.01% of 37% concentrated hydrochloric acid were added to dimethylformamide as a solvent, respectively. It is the absolute molecular weight measured by the GPC-MALS method using , and the absolute molecular weight distribution centered on the polymer region.

The composition of this apparatus, the gel permeation chromatography multi-angle light scattering photometer, is a pump (LC-20ADopt manufactured by Shimadzu Corporation), a differential refractometer (Optilab rEX Wyatt Technology) as a detector, and a multi-angle light scattering detector (DAWN HELEOS Wyatt manufactured by Technology). Specifically, a multi-angle laser light scattering photometer (MALS) and a differential refractometer (RI) are combined with a GPC (Gel Permeation Chromatography) device, and the light scattering intensity and refractive index difference of the molecular chain solution size-classified by the GPC device are elution By measuring over time, the molecular weight of the solute and its content were sequentially calculated and obtained. The measurement conditions and measurement method by the GPC device are as follows.

Column: 2 TSKgel α-M (φ7.8 mm × 30 cm, manufactured by Tosoh Corporation)

Column temperature: 40°C

Flow rate: 0.8 ml/mm

Sample preparation: 5 ml of solvent was added to 10 mg of sample (acrylic rubber), and gently stirred at room temperature (dissolution was observed). Thereafter, filtration was performed using a 0.5 μm filter.

[Glass Transition Temperature (Tg)]

The glass transition temperature (Tg) of the acrylic rubber was measured using a differential scanning calorimeter (DSC, product name "X-DSC7000", manufactured by Hitachi High-Tech Science Co., Ltd.).

[Methyl ethyl ketone insoluble content]

The methyl ethyl ketone insoluble content (%) of acrylic rubber was determined by the following method as the amount of methyl ethyl ketone insoluble content.

About 0.2 g of acrylic rubber was weighed (Xg), immersed in 100 ml of methyl ethyl ketone, left at room temperature for 24 hours, and then the filtrate obtained by filtering the insoluble content of methyl ethyl ketone using an 80 mesh wire mesh, that is, The dry solid content (Yg) obtained by evaporating and drying the filtrate in which only the rubber component dissolved in methyl ethyl ketone was dissolved was solidified was weighed and calculated by the following formula.

Methyl ethyl ketone insoluble content (%) = 100 × (X - Y) / X

[importance]

The specific gravity of the acrylic rubber was measured according to JIS K6268 Crosslinked Rubber - Method A of Density Measurement.

The measured value obtained by the following measurement method is density, and the density of water is set to 1 Mg/m ³ to be specific gravity. Specifically, the specific gravity of a rubber sample obtained according to JIS K6268 Crosslinked Rubber - Method A of Density Measurement is obtained by dividing the mass by the volume containing the voids of the rubber sample, according to JIS K6268 Crosslinked Rubber - Method A of Density Measurement It is obtained by dividing the density of the rubber sample to be measured by the density of water (if the density of the rubber sample is divided by the density of water, the numerical value is the same and the unit is lost). Specifically, the specific gravity of the rubber sample is obtained based on the following procedure.

(1) Cut a 2.5 g test piece from a rubber sample left at standard temperature (23°C ± 2°C) for at least 3 hours, and use a thin nylon thread with a mass of less than 0.010 g from a hook on a chemical balance with a precision of 1 mg. The base of the test piece is suspended so that it is 25 mm above the distribution dish for chemical balance, and the mass (m1) of the test piece is measured twice to mg in the air.

(2) Next, a beaker with a capacity of 250 cm ³ placed on a distribution dish for chemical balance is filled with distilled water cooled to a standard temperature after boiling, the test piece is immersed in it, and air bubbles adhering to the surface of the test piece are removed. and observe the movement of the scale guide for several seconds to confirm that the guide does not slowly shake due to convection, and measure the mass (m2) of the test piece in water twice in mg units.

(3) In addition, when the density of the test piece is less than 1 Mg/m ³ (when the test piece floats in water), a weight is attached to the test piece, and the mass of the weight in water (m3) and the mass of the test piece and weight (m4 ) is measured in mg units twice.

(4) For the specific gravity of the rubber sample, the density (Mg/m ³ ) was calculated based on the following formula using the average value of m1, m2, m3, and m4 measured above, and the calculated density was the density of water (1.00 Mg /m ³ ) to get the result.

(Density of rubber sample when weight is not used)

Density = m1/(m1 - m2)

(Density of rubber sample when weight is used)

Density = m1/(m1 + m3 - m4)

[Moisture content]

Water content (%) was measured according to JIS K6238-1: Oven A (Volatile Content Measurement) method.

[pH]

pH was measured with a pH electrode after dissolving 6 g (±0.05 g) of acrylic rubber in 100 g of tetrahydrofuran, adding 2.0 ml of distilled water to confirm complete dissolution.

[Complex Viscosity]

For the complex viscosity η, the temperature dispersion (40 to 120 ° C.) was measured at a strain of 473% and 1 Hz using a dynamic viscoelasticity measuring device “Rubber Process Analyzer RPA-2000” (manufactured by Alpha Technologies), and at each temperature The complex viscosity η of was obtained. Here, among the dynamic viscoelastic properties described above, the dynamic viscoelasticity at 60 ° C is taken as the complex viscosity η (60 ° C), and the dynamic viscoelasticity at 100 ° C is taken as the complex viscosity η (100 ° C), and its ratio η (100 ° C) The value of /η (60°C) was calculated.

[Mooney viscosity (ML1+4, 100℃)]

The Mooney viscosity (ML1+4, 100°C) was measured according to the JIS K6300 uncrosslinked rubber physical test method.

[Crosslinkability]

The crosslinkability of a rubber sample is the rate of change between the breaking strength of a crosslinked rubber product subjected to secondary crosslinking for 2 hours and the breaking strength of a crosslinked rubber product subjected to 4 hours ((break strength of a crosslinked rubber product for 4 hours/break strength of a crosslinked rubber product for 2 hours) × 100) was calculated and judged according to the following criteria.

◎: The breaking strength change rate is less than 10%

×: The breaking strength change rate is 10% or more

[Roll machinability]

The roll processability of the rubber sample was evaluated according to the following criteria by observing the roll-wrapability and rubber state when the rubber sample was roll-kneaded.

◎: Kneading is easy, it is easy to wind around a roll, and the surface of the rubber composition after kneading is smooth without being seen to fall off the roll.

○: Kneading is easy, and it is easy to wind around the roll, so that falling off the roll is not observed, and a part of the surface of the rubber composition after kneading is slightly uneven.

□: Kneading is easy, roll-wrapability is excellent, and the surface of the rubber composition after kneading is somewhat uneven.

△: Kneading is easy, roll-wrapability is somewhat poor, and the surface of the rubber composition after kneading is somewhat rough

×: The kneading takes a load and the roll winding property is poor

[Banbury machinability]

The Banbury processability of the rubber sample was measured by putting the rubber sample into a Banbury mixer heated to 50 ° C., mixing it for 1 minute, and then adding the compounding agent A of the rubber mixture formulation shown in Table 1 to integrate the rubber mixture in the first stage. The time until the maximum torque value is displayed, that is, BIT (Black Incorporation Time) was measured, and Comparative Example 1 was evaluated with an index of 100 (the smaller the index, the better the workability).

[Storage stability evaluation]

For the storage stability of the rubber sample, the rubber sample was put into a constant temperature and humidity bath (SH-222 manufactured by ESPEC) at 45 ° C × 80% RH, and the rate of change in water content before and after the test for 7 days was calculated, Comparative Example 1 was 100 (The smaller the index, the better the storage stability).

[Water resistance evaluation]

The water resistance of the rubber sample was tested by immersing the crosslinked product of the rubber sample in distilled water at a temperature of 85 ° C. for 100 hours in accordance with JIS K6258, and the volume change rate before and after immersion was calculated according to the following formula, Comparative Example 1 Evaluation was made with an index of 100 (the smaller the index, the better the water resistance).

Volume change rate (%) before and after immersion = ((volume of test piece after immersion - volume of test piece before immersion) / volume of test piece before immersion) × 100

[Compression permanent deformation resistance]

The compression set resistance of the rubber sample was evaluated according to the following criteria by measuring the compression set after being placed at 175° C. for 90 hours in a state in which the rubber crosslinked product of the rubber sample was compressed by 25% according to JIS K6262.

◎: compression set is less than 15%

×: compression set is 15% or more

[Evaluation of state physical properties]

The physical properties of the rubber sample were evaluated according to the following criteria by measuring the breaking strength, 100% tensile stress and elongation at break of the rubber cross-linked product of the rubber sample according to JIS K6251.

(1) The breaking strength was evaluated by denoting 10 MPa or more as ◎ and less than 10 MPa as ×.

(2) The 100% tensile stress was evaluated by denoting 5 MPa or more as ◎ and less than 5 MPa as ×.

(3) Elongation at break was evaluated with 150% or more as ◎ and less than 150% as ×.

[Evaluation of variance in methyl ethyl ketone insoluble content]

The variance evaluation of the methyl ethyl ketone insoluble content of rubber samples was evaluated based on the following criteria by measuring the methyl ethyl ketone insoluble content of 20 points randomly selected from 20 parts (20 kg) of rubber samples.

◎: Calculate the average value of the methyl ethyl ketone insoluble content of the 20 measured points, and all 20 measured points are within the range of the average value ± 3

○: The average value of the methyl ethyl ketone insoluble content of 20 measured points was calculated, and all 20 measured points were within the range of the average value ± 5 (even 1 point out of the 20 measured points was outside the range of the average value ± 3) Throw away, but all 20 points fall within the range of the average value ± 5)

×: The average value of the methyl ethyl ketone insoluble content of the 20 measured points was calculated, and even 1 point out of the 20 points measured from the range of the average value ± 5

[Evaluation of Processing Stability by Mooney Scorch Suppression]

The cooling rate of the sheet-like acrylic rubber extruded from the screw-type twin-screw extrusion dryer described in Japanese Patent No. 6683189 and the Mooney scorch stability of the acrylic rubber composition were evaluated.

[Example 1]

As shown in Table 2-1, in a mixing vessel equipped with a homomixer, 46 parts of pure water, 4.5 parts of ethyl acrylate, 64.5 parts of n-butyl acrylate, 29.5 parts of methoxyethyl acrylate and 1.5 parts of monon-butyl fumarate as monomer components Part, 1.8 parts of octyloxydioxyethylene phosphate sodium salt as an emulsifier was added and stirred to obtain a monomer emulsion.

170 parts of pure water and 3 parts of the monomer emulsion obtained above were put into a polymerization reactor equipped with a thermometer and a stirring device, and after cooling to 12° C. under a nitrogen stream, 0.00033 part of ferrous sulfate, 0.02 part of sodium ascorbate, and inorganic A polymerization reaction was initiated by adding 0.2 parts of potassium persulfate as a radical generating agent. The temperature in the polymerization reactor was maintained at 23° C., and the remainder of the monomer emulsion was continuously added dropwise over 3 hours, 0.0072 part of n-dodecylmercaptan 50 minutes after the start of the reaction, 0.0036 part of n-dodecylmercaptan after 100 minutes, and 120 minutes later, 0.4 part of sodium L-ascorbate was added to continue the polymerization reaction, and when the polymerization conversion reached approximately 100%, hydroquinone as a polymerization terminator was added to stop the polymerization reaction, thereby obtaining an emulsion polymerization solution. .

Then, in a coagulation bath equipped with a thermometer and a stirring device, it was heated to 80 ° C. and vigorously stirred at 600 revolutions of the stirring blade of the stirring device (circumferential speed: 3.1 m / s), 2% aqueous magnesium sulfate solution (sulfuric acid as a coagulant) In 350 parts of a coagulation solution using magnesium), the obtained emulsion polymerization solution was heated to 80°C and continuously added to coagulate the polymer, thereby obtaining a coagulation slurry containing acrylic rubber crumb and water as a coagulation product. Water-containing crumb was obtained by draining water from the coagulated layer while separating the crumb from the obtained slurry by filtration.

194 parts of hot water (70℃) was added to the coagulation tank where the filtered and separated hydrous crumbs remained, stirred for 15 minutes to wash the water-containing crumbs, and then the moisture was discharged. The water-containing crumbs were washed (the total number of washings was twice). The washed hydrous crumb (hydrous crumb temperature: 65°C) was supplied to the screw-type twin-screw extrusion dryer 5, and dehydrated and dried to extrude a sheet-like dried rubber having a width of 300 mm and a thickness of 10 mm. Next, the sheet-shaped dried rubber was cooled at a cooling rate of 200°C/hr using a transport type cooling device connected directly to the screw type twin screw extrusion dryer 5 and installed.

On the other hand, the screw-type twin-screw extrusion dryer used in Example 1 is composed of one supply barrel, three dewatering barrels (first to third dehydration barrels), and five drying barrels (first to fifth drying barrels). has been The first dewatering barrel drains water, and the second and third dewatering barrels drain steam. The operating conditions of the screw-type twin-screw extrusion dryer were as follows.

Water content:

Moisture content of hydrous crumb after draining from the first dewatering barrel: 20%

Moisture content of hydrous crumb after doubling in the third dewatering barrel: 10%

Moisture content of hydrous crumb after drying in the fifth drying barrel: 0.4%

rubber temperature:

·Temperature of water-containing crumb supplied to the supply barrel: 65℃

・Temperature of rubber discharged from screw type twin screw extrusion dryer: 140°C

Set temperature for each barrel:

1st dewatering barrel: 100℃

2nd dewatering barrel: 120℃

3rd dewatering barrel: 120℃

1st drying barrel: 120 ℃

2nd drying barrel: 130 ℃

3rd drying barrel: 140 ℃

4th drying barrel: 160 ℃

5th drying barrel: 180 ℃

Driving conditions:

Diameter of screw (D): 132 mm

·Overall length of screw (L): 4620 mm

·L/D: 35

Rotational speed of screw: 135 rpm

Decompression degree of drying barrel: 10 kPa

Amount of rubber extruded from the die: 700 kg/hr

Resin pressure in die: 2 MPa

·Maximum torque in the screw type twin screw extrusion dryer: 15 N·m

After cooling the extruded sheet-like dry rubber to 50°C, it was cut with a cutter and laminated so as to make 20 parts (20 kg) while not reaching 40°C or lower to obtain veil-like acrylic rubber (A). Reactive group content, ash content, ash component amount, methyl ethyl ketone insoluble content, pH, specific gravity, glass transition temperature (Tg), water content, molecular weight, molecular weight distribution, and complex of 100 ° C. and 60 ° C. of the obtained acrylic rubber (A) Viscosity was measured and shown in Table 2-2. In addition, a storage stability test of acrylic rubber (A) was conducted to determine the rate of change in water content, and the results are shown in Table 2-2.

Next, using a Banbury mixer, 100 parts of acrylic rubber (A) and compounding agent A of "Formulation 1" described in Table 1 were charged, and mixed at 50°C for 5 minutes (first stage mixing). BIT at this time was measured to evaluate the Banbury workability of acrylic rubber, and the results are shown in Table 2-2.

Next, the obtained mixture was transferred to a roll at 50°C, and the compounding agent B of "Formulation 1" was blended and mixed (second stage mixing) to obtain a rubber composition. The roll workability at this time was evaluated and the results are shown in Table 2-2.

[Table 1]

The obtained rubber composition was placed in a mold having a length of 15 cm, a width of 15 cm, and a depth of 0.2 cm, and primary crosslinking was performed by pressing at 180° C. for 10 minutes while pressurizing with a press pressure of 10 MPa. , and further heated at 180° C. for 2 hours to perform secondary crosslinking, thereby obtaining a sheet-like crosslinked rubber product. Then, a test piece of 3 cm × 2 cm × 0.2 cm was cut out from the obtained cross-linked rubber sheet, and water resistance, compression set resistance, and state physical properties were evaluated. In addition, the state physical properties of the crosslinked sheet-shaped rubber subjected to the secondary crosslinking for an additional 2 hours were measured to evaluate the crosslinkability. Their results are shown in Table 2-2.

[Example 2]

The emulsifier was 1.8 parts of sodium nonylphenyloxyhexaoxyethylene phosphate, the amount of potassium persulfate as an inorganic radical generator was 0.21 parts, and the post-addition of the chain transfer agent n-dodecylmercaptan was 0.017 parts after 50 minutes and 0.017 parts after 100 minutes, respectively. Part and 120 minutes later, except for changing to 0.017 part, the procedure was the same as in Example 1 to obtain acrylic rubber (B), and each property was evaluated. Their results are shown in Table 2-2.

[Example 3]

The monomer components were changed to 48.25 parts of ethyl acrylate, 50 parts of n-butyl acrylate and 1.75 parts of mono-n-butyl fumarate, and the emulsifier was changed to 1.8 parts of tridecyloxyhexaoxyethylene phosphate sodium salt, and the water-containing crumb after washing was heated to 160°C. After drying to a water content of 0.4% using a hot air dryer to obtain crumb-like acrylic rubber, it is the same as in Example 1 except that it is filled in a 300 × 650 × 300 mm baler and compacted for 25 seconds at a pressure of 3 MPa to obtain a bale-like acrylic rubber. Thus, acrylic rubber (C) was obtained. Each characteristic of the acrylic rubber (C) was evaluated (the compounding agent was changed to "Formulation 2"), and the results are shown in Table 2-2.

[Example 4]

Acrylic rubber ( D) was obtained and each characteristic (the compounding agent was changed to “Formulation 3”) was evaluated. Their results are shown in Table 2-2.

[Example 5]

Acrylic rubber (E) was prepared in the same manner as in Example 3 except that the monomer components were changed to 42.2 parts of ethyl acrylate, 35 parts of n-butyl acrylate, 20 parts of methoxyethyl acrylate, 1.5 parts of acrylonitrile, and 1.3 parts of vinyl chloroacetate. was obtained and evaluated for each characteristic (the formulation was changed to “Formula 4”). Their results are shown in Table 2-2.

[Example 6]

The monomer components were changed to 48.25 parts of ethyl acrylate, 50 parts of n-butyl acrylate and 1.75 parts of mono-n-butyl fumarate, and the emulsifier was changed to 1.8 parts of tridecyloxyhexaoxyethylene phosphate sodium salt, and the water-containing crumb after washing was heated to 160°C. After drying to a water content of 0.4% using a hot air dryer to obtain crumb-like acrylic rubber, it is the same as in Example 2 except that it is filled in a 300 × 650 × 300 mm baler and compacted for 25 seconds at a pressure of 3 MPa to obtain a bale-like acrylic rubber. Thus, acrylic rubber (F) was obtained. Each characteristic of the acrylic rubber (F) was evaluated (the compounding agent was changed to "Formulation 2"), and the results are shown in Table 2-2.

[Example 7]

Acrylic rubber ( G) was obtained and each characteristic (the compounding agent was changed to “Formulation 3”) was evaluated. Their results are shown in Table 2-2.

[Example 8]

Acrylic rubber (H) was obtained and evaluated for each characteristic (the formulation was changed to "Formulation 4"). Their results are shown in Table 2-2.

[Example 9]

Acrylic rubber (I) was obtained and each characteristic was evaluated. Their results are shown in Table 2-2.

[Comparative Example 1]

Without adding a chain transfer agent, the coagulation reaction was carried out by adding 0.7% magnesium sulfate aqueous solution to the stirred emulsion polymerization solution after emulsion polymerization (stirring water: 100 rpm, circumferential speed: 0.5 m/s), and baling with a baler was performed. An acrylic rubber (J) was obtained and its properties were evaluated in the same manner as in Example 9, except that crumb-like acrylic rubber was obtained without the addition. Their results are shown in Table 2-2.

[Comparative Example 2]

The emulsifier was changed to 0.709 parts of sodium lauryl sulfate and 1.82 parts of polyoxyethylene dodecyl ether, and sodium sulfate was added to the stirring emulsion polymerization solution after emulsion polymerization (stirring water 100 rpm, circumferential speed 0.5 m/s) for coagulation reaction. In the washing step, 194 parts of industrial water was added to wash the hydrous crumb, stirred in the coagulation tank at 25 ° C for 5 minutes, and then the operation of discharging water from the coagulation tank was performed only twice, and further baled with a baler An acrylic rubber (K) was obtained and its properties were evaluated in the same manner as in Example 9, except that a crumb-like acrylic rubber was obtained without the addition. Their results are shown in Table 2-2.

[Table 2-1]

[Table 2-2]

From Table 2-1 and Table 2-2, the absolute molecular weight measured by the GPC-MALS method with the (meth)acrylic acid ester of the present invention as the main component and the dimethylformamide-based solvent as the developing solvent and the weight in the absolute molecular weight distribution The average molecular weight (Mw) is 1,000,000 or more, the ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) is 3.4 or more, and the ash content is 0.4% by weight or less, and sodium, magnesium, and calcium in the ash , Acrylic rubbers (A) to (I) having a total amount of phosphorus and sulfur of 80% by weight or more are excellent in state physical properties including roll processability, water resistance and strength properties, and also have Banbury processability, storage stability, crosslinkability, and compression resistance. It can be seen that the deformation properties are remarkably excellent (Examples 1 to 9).

From Table 2-1 and Table 2-2, the acrylic rubbers (A) to (K) prepared under the conditions of Examples and Comparative Examples of the present application are selected from the group consisting of an ionic reactive group, a carboxyl group, an epoxy group, and a chlorine atom. Since it has at least one kind of reactive group and has a large weight average molecular weight (Mw), it can be seen that the state physical properties including crosslinkability, compression set resistance and strength characteristics are excellent (Examples 1 to 9 and Comparative Example 1 ~2). However, the acrylic rubbers (J) to (K) were poor in roll processability, Banbury processability, water resistance and storage stability (Comparative Example 1), and also poor in water resistance and storage stability (Comparative Example 2).

From Table 2-2, with respect to roll processability, the molecular weight distribution of the ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) is highly related, and the wider the molecular weight distribution, the better the roll processability. It turns out that this is good (Comparison of Examples 1-9 and Comparative Example 2 and Comparative Example 1). In addition, in order to highly balance strength characteristics and roll workability, the weight average molecular weight (Mw) is high and the molecular weight distribution centered on the high molecular weight region (the ratio of the z average molecular weight (Mz) to the weight average molecular weight (Mw) (Mz/ It was important that Mw) was on the high side.

From Table 2-1 and Table 2-2, an acrylic rubber having excellent strength characteristics and excellent roll processability having a large weight average molecular weight (Mw) and a wide Mw/Mn was selected from a specific amount of an inorganic radical generator and a chain transfer agent, It turns out that it can manufacture by using n-dodecyl mercaptan especially (Examples 1-9). From Table 2-2, furthermore, rather than continuously adding n-dodecylmercaptan (Example 9), the amount of inorganic radical generator used was reduced and n-dodecylmercaptan was not initially added. It turns out that roll workability can be further improved without impairing strength characteristics by post-adding batchwise (Examples 1-8). This increases the length of one polymer chain by reducing the amount of inorganic radical generating agent and not adding a chain transfer agent at the beginning. Strength characteristics and roll workability are highly balanced by making Mw/Mn large and wide. In addition, in order to effectively widen Mw/Mn, the number of batchwise post-additions has a greater effect than the difference in the addition amount of batchwise post-addition of the chain transfer agent, and the number of batchwise post-additions is 2 times rather than 3 times Mw /Mn broadens (comparison of Examples 3 to 5 and Examples 6 to 8), but continuous addition of the chain transfer agent makes the expansion of Mw/Mn somewhat limited (Example 9). In addition, although not shown in Table 2-2, in the examples of the present application, sodium ascorbate as a reducing agent was added 120 minutes after the start of polymerization. The effect of widening Mw/Mn is increasing. On the other hand, although not shown in the examples herein, when polymerization is performed using an organic radical generating agent, the ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) does not widen and the roll workability is poor. I am checking.

From Table 2-2, it can be seen that the acrylic rubbers (A) to (I) of the present invention are overwhelmingly superior in terms of water resistance (comparison between Examples 1 to 9 and Comparative Examples 1 to 2). From Table 2-2, acrylic rubbers (A) to (I), which were further excellent in roll workability and strength characteristics and significantly excellent in water resistance, were continuously or batchwise applied as a chain transfer agent using an inorganic radical generating agent. In the coagulation step of the emulsion polymerization after addition and emulsion polymerization, the coagulation reaction is performed by adding the coagulation solution to the stirring coagulation solution instead of adding the coagulant solution to the emulsion polymerization solution. More preferably, the coagulation solution is vigorously It can be seen that it can be produced by stirring (the number of stirring 600 rpm / circumferential speed 3.1 m / s) and increasing the concentration of the coagulant in the coagulant solution being stirred (comparison of Examples 1 to 9 and Comparative Example 1) . This data will be described later. This coagulation reaction generates hydrous crumbs concentrated to crumb diameters in the range of 710 μm to 4.75 mm, and the efficiency of removing emulsifiers and coagulants in the washing and dewatering process is overwhelmingly improved, and acrylic By reducing the amount of ash in the rubber, water resistance can be significantly improved.

From Table 2-2, it can be seen that water resistance is also superior to chlorine atom in the case of a carboxyl group or an epoxy group among ion reactive groups (Examples 3 to 4 and Examples 6 to 7 and Examples 5 and Examples comparison of 8).

From Table 2-2, the total amount of elements of phosphorus, magnesium, sodium, calcium and sulfur in the ash of the acrylic rubbers (A) to (I) of the present invention and the acrylic rubbers (J) to (K) of the comparative examples were all 90 weight %, and the properties such as water resistance and mold release of acrylic rubber are excellent, and furthermore, it can be seen that the water resistance is excellent when the ratio of phosphorus and magnesium in the ash is increased (ash amount in Comparative Example 1). Silver was twice or more than that of Comparative Example 2, but the water resistance evaluation was about the same).

From Table 2-2, with respect to water resistance, it was found that acrylic rubbers (A) to (B) dehydrated (moisture was squeezed out) before drying the hydrous crumb significantly reduced the amount of ash and improved water resistance. (Comparison of Examples 1 to 2 and Examples 3 to 9). In addition, when looking at the amount of components in the ash of acrylic rubber (A) to (B), five elements of phosphorus (P), magnesium (Mg), sodium (Na), calcium (Ca) and sulfur (S) account for a large proportion. However, as the ash removal proceeds, it can be seen that most of them are phosphorus (P) and magnesium (Mg). This is presumed to be that the sodium phosphate of the emulsifier is salt-exchanged with the magnesium sulfate of the coagulant and remains in the hydrous crumb as magnesium phosphate, which cannot be sufficiently removed in the washing step, but can be reduced by dewatering (squeezing). In addition, it was found that the fact that the components in the ash of the acrylic rubber were high in phosphorus and magnesium did not deteriorate the water resistance (Comparison of Examples 1 to 9 and Comparative Example 1 and Comparative Example 2).

From Table 2-2, it can be seen that the acrylic rubbers (A) to (I) of the present invention are excellent in roll processability, water resistance and strength characteristics, as well as excellent in Banbury processability, and excellent in both roll processability and Banbury processability. Yes (Examples 1-9). It can be seen that the Banbury processability of acrylic rubber is correlated with the amount of methyl ethyl ketone insoluble content, and the Banbury processability is excellent when the methyl ethyl ketone insoluble content is small (comparison between Examples 1 to 9 and Comparative Example 1). The amount of insoluble methyl ethyl ketone in acrylic rubber can be reduced by emulsion polymerization in the presence of a chain transfer agent (Examples 3 to 8 and Comparative Example 2). Since the conversion rate increases rapidly when the conversion rate is increased, it is understood that the generation of methyl ethyl ketone insoluble components can be suppressed even in Examples 3 to 8 in which the chain transfer agent is added after addition. The amount of insoluble methyl ethyl ketone in acrylic rubber is also remarkably reduced by drying the hydrous crumb with a screw-type twin-screw extrusion dryer, and the Banbury processability of the produced acrylic rubber is greatly improved (Examples 1 and 2 and Comparison of Examples 3-8). In the present invention, although not shown in this Example, the amount of insoluble methyl ethyl ketone rapidly increased in emulsion polymerization without the addition of a chain transfer agent (Comparative Example 1) contained substantially no water in the screw-type twin-screw extrusion dryer It has been confirmed that the Banbury workability can be significantly improved without losing it by melt-kneading in a non-free state (moisture content less than 1% by weight) and impairing the roll workability of acrylic rubber.

From Table 2-2, it can be seen that the acrylic rubbers (A) to (I) of the present invention are excellent in roll processability, water resistance and strength characteristics, and also remarkably excellent in storage stability (Examples 1 to 9) . The storage stability of acrylic rubber is largely related to the specific gravity of the acrylic rubber, and when the specific gravity is large, it can be seen that the storage stability is excellent without entraining air in the acrylic rubber (Examples 1 to 2 and Examples 3 to 9). and comparison with Comparative Examples 1-2). Acrylic rubber having a high specific gravity is baled by compressing crumb-like acrylic rubber with a baler (Examples 3 to 9), more preferably by extruding into a sheet form with a screw-type twin-screw extrusion dryer, laminating and baling (Examples 3 to 9). Examples 1-2) can be obtained. In the present invention, in particular, a veil-like acrylic rubber obtained by laminating sheet-like acrylic rubber melt-kneaded and dried under reduced pressure has excellent state properties including short-time crosslinking properties, roll workability, compression set resistance, strength properties, and water resistance. It can be seen that the storage stability is remarkably improved without damaging (Examples 1 and 2). It can be seen that the storage stability of acrylic rubber is more preferable when the amount of ash is smaller or when the pH is specified (Examples 1 to 9).

From Table 2-2, the acrylic rubbers (A) to (K) of Examples and Comparative Examples of the present invention have excellent crosslinking properties and compression set resistance by having a carboxyl group, an epoxy group, or an ion-reactive group such as a chlorine atom. can know that

[About the grain size of the generating function crumb]

For the hydrous crumbs produced in the coagulation process of Examples 1 to 9 and Comparative Example 1, (1) 710 μm to 6.7 mm (passing 6.7 mm without passing through 710 μm), (2) 710 μm to 4.75 mm ( 4.75 mm without passing through 710 μm), (3) 710 μm to 3.35 mm (passing through 3.35 mm without passing through 710 μm) to the total amount of wet crumbs were measured using a JIS sieve. Their results are shown below.

Example 1: (1) 90 wt%, (2) 90 wt%, (3) 87 wt%

Example 2: (1) 92%, (2) 91%, (3) 89%

Example 3: (1) 89%, (2) 87%, (3) 83%

Example 4: (1) 91 wt%, (2) 90 wt%, (3) 83 wt%

Example 5: (1) 93 wt%, (2) 91 wt%, (3) 89 wt%

Example 6: (1) 95 wt%, (2) 89 wt%, (3) 80 wt%

Example 7: (1) 92%, (2) 92%, (3) 88%

Example 8: (1) 94 wt%, (2) 93 wt%, (3) 87 wt%

Example 9: (1) 90 wt%, (2) 89 wt%, (3) 88 wt%

Comparative Example 1: (1) 15% by weight, (2) 1% by weight, (3) 0% by weight

From these results, even if the size of the hydrous crumb produced in the solidification step is the same, the amount of acrylic rubber or the ash remaining in the acrylic rubber is different, and the cleaning efficiency of those with a large specific ratio of (1) to (3) is higher. It can be seen that the amount of ash is high and the water resistance is excellent (comparison of Examples 3 to 9 and Comparative Example 1 in Table 2-2). In addition, the water-containing crumb with a high specific ratio of (1) to (3) has a high ash removal rate at the time of dehydration of 20% by weight, further reducing the amount of ash and significantly improving the water resistance of acrylic rubber. It can be seen (comparison of Examples 1 to 2 and Examples 3 to 9).

For reference, in the coagulation step, the same procedure as in Comparative Example 1 was performed except that the emulsion polymerization solution was added to the coagulation solution (Reference Example 1), and the emulsion polymerization solution was added to the coagulation solution, so that the coagulant concentration of the coagulation solution In the same manner as in Comparative Example 1 (Reference Example 2), except for changing from 0.7% by weight to 2% by weight, the particle size ratio of the resulting hydrous crumb and the amount of ash in the acrylic rubber were measured.

Reference Example 1: (1) 90% by weight, (2) 55% by weight, (3) 22% by weight, ash content 0.55% by weight

Reference Example 2: (1) 91% by weight, (2) 70% by weight, (3) 40% by weight, ash content 0.41% by weight

From these results, the amount of ash in the acrylic rubber was changed to a method in which the concentration of the coagulating liquid was increased (2%) in the coagulation reaction and the emulsion polymerization liquid was added to the coagulating liquid being stirred (Lx↓), and The crumb diameter of the hydrous crumb produced by vigorously agitating the coagulant solution (agitation water 600 rpm/circumferential speed 3.1 m/s) can be concentrated in a specific range of 710 μm to 4.75 mm, cleaning efficiency by hot water and The removal efficiency of the emulsifier or coagulant during dehydration is remarkably improved, reducing the amount of ash of acrylic rubber, and not impairing the properties of acrylic rubber, such as crosslinkability, roll processability, compression set resistance, and state physical properties including strength characteristics. It can be seen that the water resistance can be significantly improved (Examples 1 and 2). On the other hand, it has been confirmed that the presence or absence of the addition of the chain transfer agent has little effect on the particle size of the resulting hydrous crumb.

[Example 10]

As shown in Table 3-1, the monomer components were 74.5 parts of ethyl acrylate, 17 parts of n-butyl acrylate, 7 parts of methoxyethyl acrylate, and 1.5 parts of mono-n-butyl fumarate, and tridecyloxyhexaoxyethylene phosphate as an emulsifier. Acrylic rubber (L) was obtained in the same manner as in Example 2 except for changing to 1.8 parts of sodium salt, and each property was evaluated, and the results are shown in Table 3-2. In addition, Table 3-1 shows the water content, maximum torque, specific power, specific power, shear rate and shear viscosity after dehydration (drainage) of the screw-type twin screw extrusion dryer.

[Example 11]

Examples except that the monomer components are changed to 74.5 parts of ethyl acrylate, 17 parts of n-butyl acrylate, 7 parts of methoxyethyl acrylate, 1.5 parts of mono-n-butyl fumarate, and 1.8 parts of tridecyloxyhexaoxyethylene phosphate sodium salt as the emulsifier. In the same manner as in 1, acrylic rubber (M) was obtained, and each characteristic was evaluated, and the results are shown in Table 3-2. In addition, Table 3-1 shows the water content, maximum torque, specific power, specific power, shear rate and shear viscosity after dehydration (drainage) of the screw-type twin screw extrusion dryer.

[Example 12]

The monomer components are 28 parts of ethyl acrylate, 38 parts of n-butyl acrylate, 27 parts of methoxyethyl acrylate, 5 parts of acrylonitrile and 2 parts of allylglycidyl ether, and the operating conditions of the screw type twin screw extrusion dryer are high share ( Maximum torque 45 N m) was carried out in the same manner as in Example 10, acrylic rubber (N) was obtained, and each characteristic (the compounding agent was changed to “Formulation 3”) was evaluated, and the results are shown in the table It is shown in 3-2. In addition, Table 3-1 shows the water content, maximum torque, specific power, specific power, shear rate and shear viscosity after dehydration (drainage) of the screw-type twin screw extrusion dryer.

[Example 13]

Except for changing the monomer components to 48.5 parts of ethyl acrylate, 50 parts of n-butyl acrylate, and 1.5 parts of mono-n-butyl fumarate, the same procedure as in Example 12 was performed to obtain acrylic rubber (O), and each characteristic (the compounding agent was 1”) were evaluated, and their results are shown in Table 3-2. In addition, Table 3-1 shows the water content, maximum torque, specific power, specific power, shear rate and shear viscosity after dehydration (drainage) of the screw-type twin screw extrusion dryer.

[Example 14]

Except for changing the monomer components to 48.25 parts of ethyl acrylate, 50 parts of n-butyl acrylate, and 1.75 parts of mono-n-butyl fumarate, the same procedure as in Example 12 was performed to obtain acrylic rubber (P), and each characteristic (the compounding agent was 2”) were evaluated, and their results are shown in Table 3-2. In addition, Table 3-1 shows the water content, maximum torque, specific power, specific power, shear rate and shear viscosity after dehydration (drainage) of the screw-type twin screw extrusion dryer.

[Example 15]

The monomer components are 28 parts of ethyl acrylate, 38 parts of n-butyl acrylate, 27 parts of methoxyethyl acrylate, 5 parts of acrylonitrile and 2 parts of allylglycidyl ether, and the operating conditions of the screw type twin screw extrusion dryer are high share ( Maximum torque 45 N m) was carried out in the same manner as in Example 11, acrylic rubber (Q) was obtained, and each characteristic (the compounding agent was changed to “Formulation 3”) was evaluated, and the results are shown in the table It is shown in 3-2. In addition, Table 3-1 shows the water content, maximum torque, specific power, specific power, shear rate and shear viscosity after dehydration (drainage) of the screw-type twin screw extrusion dryer.

[Example 16]

Except for changing the monomer components to 48.5 parts of ethyl acrylate, 50 parts of n-butyl acrylate, and 1.5 parts of mono-n-butyl fumarate, the same procedure as in Example 15 was carried out to obtain acrylic rubber (R), and each characteristic (the compounding agent was 1”) were evaluated, and their results are shown in Table 3-2. In addition, Table 3-1 shows the water content, maximum torque, specific power, specific power, shear rate and shear viscosity after dehydration (drainage) of the screw-type twin screw extrusion dryer.

[Example 17]

Except for changing the monomer components to 48.25 parts of ethyl acrylate, 50 parts of n-butyl acrylate, and 1.75 parts of mono-n-butyl fumarate, acrylic rubber (S) was obtained and each characteristic (the compounding agent was 2”) were evaluated, and their results are shown in Table 3-2. In addition, Table 3-1 shows the water content, maximum torque, specific power, specific power, shear rate and shear viscosity after dehydration (drainage) of the screw-type twin screw extrusion dryer.

[Table 3-1]

[Table 3-2]

From Table 3-2, it can be seen that the acrylic rubbers (N) to (S) of the present invention are excellent in state physical properties including Banbury processability, water resistance, storage stability, crosslinkability, compression set resistance, and strength characteristics, and have remarkable roll processability. It turns out that this is improved (comparison of Examples 12-17 and Examples 10-11). This is an acrylic rubber composed of a high molecular weight component and a low molecular weight component emulsion-polymerized by post-adding a chain transfer agent and dried at a high share using a screw type twin screw extrusion dryer to obtain an acrylic rubber with a further balanced molecular weight and molecular weight distribution. Processability can be significantly improved.

In addition, for each rubber sample, the variance in the amount of methyl ethyl ketone insoluble was evaluated by the method described above. That is, the variance evaluation of the methyl ethyl ketone insoluble content of rubber samples was evaluated based on the above criteria by measuring the methyl ethyl ketone insoluble content of 20 points randomly selected from 20 parts (20 kg) of rubber samples.

When the variance evaluation of the amount of methyl ethyl ketone insoluble was performed using the acrylic rubbers (L) to (S) obtained in Examples 10 to 17 and the acrylic rubber (J) obtained in Comparative Example 1 as rubber samples, according to the present invention The results of the acrylic rubbers (L) to (S) of Examples 10 to 17 were all "◎", but the results of the acrylic rubber (J) of Comparative Example 1 were "x".

This is because the acrylic rubbers (L) to (S) are melt-kneaded in a screw-type twin-screw extrusion dryer and melt-kneaded and dried in a substantially water-free state (moisture content less than 1% by weight), so that the methyl ethyl ketone insoluble content is almost It is presumed that Banbury processability could be remarkably improved without impairing physical properties including crosslinkability, roll processability, compression set resistance, and strength characteristics, because the methyl ethyl ketone insoluble content was almost eliminated.

On the other hand, the hydrous crumb produced after emulsion polymerization and coagulation washing under the conditions for producing the acrylic rubber (J) of Comparative Example 1 was put into a screw-type twin-screw extrusion dryer under the same conditions as in Example 10 and extruded and dried. The methyl ethyl ketone insoluble content and the deviation of the methyl ethyl ketone insoluble content measured for acrylic rubber were approximately equal to those of acrylic rubber (L), and it was found that the Banbury workability could also be improved, but the roll workability was evaluated as "x" It was the same.

With respect to the acrylic rubber compositions containing the acrylic rubbers (L) to (S) of Examples 10 to 17, the Mooney scorch time t5 (minutes) at a temperature of 125 ° C. was measured according to JIS K 6300, and Mooney Scotch storage stability was evaluated according to the following criteria. As a result, all were good results of "◎".

◎: Mooney scorch time t5 exceeding 2.0 minutes

○: Mooney scorch time t5 is 1.5 to 2.0 minutes

×: Mooney scorch time t5 is less than 1.5 minutes

On the other hand, with respect to these acrylic rubbers (L) to (S), the cooling rate of the sheet-shaped dry rubber extruded from the screw-type twin-screw extrusion dryer is as fast as about 200°C/hr, similar to Example 1, and is 40°C/hr in all cases. More than that.

[Releasability to mold]

The rubber compositions of the acrylic rubbers (L) to (S) obtained in Examples 10 to 17 were press-injected into a 10 mmφ×200 mm mold, and the crosslinked rubber products after crosslinking at a mold temperature of 165° C. for 2 minutes were taken out, and the following criteria When the mold releasability was evaluated by, all of the acrylic rubbers (L) to (S) were evaluated as "◎" and were good.

◎: It can be easily released from the mold, and there is no mold residue.

○: It can be easily released from the mold, but very small mold residues are observed

△: It can be easily released from the mold, but there is a slight mold residue.

×: Difficult to remove from mold

1 Acrylic rubber manufacturing system
3 coagulation device
4 cleaning device
5 screw type extruder
6 cooling unit
7 Baling device

Claims (55)

(meth)acrylic acid ester as the main component, dimethylformamide-based solvent as the developing solvent, the absolute molecular weight measured by the GPC-MALS method and the weight average molecular weight (Mw) by the absolute molecular weight distribution are 1,000,000 or more, and the weight average molecular weight (Mw) and the number average molecular weight (Mn) ratio (Mw/Mn) is 3.4 or more, the amount of ash is 0.4% by weight or less, and the total amount of sodium, magnesium, calcium, phosphorus and sulfur in the ash is 80% by weight or more. According to claim 1,
An acrylic rubber having a ratio (Mw/Mn) of a weight average molecular weight (Mw) to a number average molecular weight (Mn) of 3.5 or more. According to claim 1 or 2,
An acrylic rubber having a ratio (Mw/Mn) of a weight average molecular weight (Mw) to a number average molecular weight (Mn) in the range of 3.7 to 6.5. According to any one of claims 1 to 3,
An acrylic rubber having a reactive group. According to any one of claims 1 to 4,
An acrylic rubber in which the reactive group is an ionic reactive group. According to any one of claims 1 to 5,
An acrylic rubber wherein the reactive group is at least one reactive group selected from the group consisting of a carboxyl group, an epoxy group and a chlorine atom. According to any one of claims 1 to 6,
An acrylic rubber is a bonding unit derived from at least one (meth)acrylic acid ester selected from the group consisting of (meth)acrylic acid alkyl ester and (meth)acrylic acid alkoxyalkyl ester, a bonding unit derived from a reactive group-containing monomer, and other monomers An acrylic rubber comprising a bond unit derived from According to any one of claims 1 to 7,
An acrylic rubber having a ratio (Mz/Mw) of z average molecular weight (Mz) to weight average molecular weight (Mw) in the range of 1.3 to 3. According to any one of claims 1 to 8,
An acrylic rubber having a methyl ethyl ketone insoluble content of 50% by weight or less. According to any one of claims 1 to 9,
An acrylic rubber in which the value when the amount of methyl ethyl ketone insoluble content is measured at 20 points falls within the range of (average value ± 5)% by weight. According to any one of claims 1 to 10,
An acrylic rubber having a complex viscosity ([η] 60°C) at 60°C of 15,000 [Pa·s] or less. According to any one of claims 1 to 11,
An acrylic rubber having a ratio ([η]100°C/[η]60°C) of a complex viscosity at 100°C ([η]100°C) to a complex viscosity at 60°C ([η]60°C) of 0.8 or more. According to any one of claims 1 to 12,
Acrylic rubber with a specific gravity of 0.8 or more. According to any one of claims 1 to 13,
A sheet or veil of acrylic rubber. According to any one of claims 1 to 14,
An acrylic rubber obtained by emulsion polymerization using a phosphoric acid ester salt or a sulfuric acid ester salt as an emulsifier. According to any one of claims 1 to 15,
An acrylic rubber obtained by coagulating a polymerization solution produced in an emulsion polymerization step by using an alkali metal salt or a Group 2 metal salt of the periodic table as a coagulant and drying it. According to any one of claims 1 to 16,
An acrylic rubber obtained by melting, kneading and drying after solidification. According to claim 17,
An acrylic rubber wherein the above melt kneading and drying are performed in a state in which water is not substantially contained. The method of claim 17 or 18,
An acrylic rubber wherein the above melt kneading and drying are performed under reduced pressure. According to any one of claims 17 to 19,
An acrylic rubber which is cooled at a cooling rate of 40° C./hr or more after the above melt kneading and drying. The method of any one of claims 1 to 20,
An acrylic rubber obtained by washing, dehydrating, and drying hydrous crumb having a particle size of 710 μm to 6.7 mm in a ratio of 50% by weight or more. An emulsion step of emulsifying an acrylic rubber monomer component containing (meth)acrylic acid ester as a main component with water and an emulsifier;
An emulsion polymerization step in which polymerization is initiated in the presence of a redox catalyst containing an inorganic radical generator and a reducing agent, and a chain transfer agent is batch-wise post-added during the polymerization to continue polymerization to obtain an emulsion polymerization solution;
A coagulation step of adding the obtained emulsion polymerization solution to a stirred coagulation solution and coagulating it to generate a hydrous crumb;
A cleaning step of washing the generated hydrous crumb with hot water;
A dehydration step of dewatering the washed hydrous crumb;
Drying process of drying the dehydrated hydrous crumb to less than 1% by weight
Method for producing acrylic rubber comprising a. The method of claim 22,
A method for producing an acrylic rubber for producing the acrylic rubber according to any one of claims 1 to 21. The method of claim 22 or 23,
A method for producing acrylic rubber, wherein emulsion polymerization is performed using a phosphoric acid ester salt or a sulfuric acid ester salt as an emulsifier. The method of any one of claims 22 to 24,
A method for producing acrylic rubber in which an emulsion polymerized polymerization solution is coagulated by using an alkali metal salt or a periodic table group 2 metal salt as a coagulant and dried. According to claim 25,
A method for producing acrylic rubber in which a polymerization solution generated in an emulsion polymerization step is added to an aqueous solution containing a coagulant containing an alkali metal salt or a metal salt of Group 2 of the periodic table, and stirred to coagulate it. The method of any one of claims 22 to 26,
A method for producing acrylic rubber in which a polymerization solution produced in an emulsion polymerization step is brought into contact with a coagulant to solidify, followed by melt kneading and drying. The method of claim 27,
A method for producing acrylic rubber in which the above melt kneading and drying are performed in a state in which water is not substantially contained. The method of claim 27 or 28,
A method for producing acrylic rubber in which the melt kneading and drying are performed under reduced pressure. The method of any one of claims 27 to 29,
A method for producing acrylic rubber in which the above melt kneading and drying are performed with a screw type twin screw extrusion dryer. 31. The method of claim 30,
A method for producing acrylic rubber, wherein the maximum torque of a screw-type twin-screw extrusion dryer during melt kneading and drying is 20 N m or more. The method of any one of claims 27 to 31,
A method for producing acrylic rubber in which acrylic rubber after melt kneading and drying is cooled at a cooling rate of 40°C/hr or higher. The method of any one of claims 22 to 32,
A process for producing acrylic rubber, wherein the concentration of the coagulant in the coagulant solution is 1% by weight or more. The method of any one of claims 22 to 33,
A method for producing acrylic rubber in which the stirring number of the coagulating solution being stirred is 100 rpm or more. The method of any one of claims 22 to 34,
A process for producing acrylic rubber wherein the circumferential speed of the coagulating solution being stirred is 1 m/s or more. The method of any one of claims 22 to 35,
A method for producing acrylic rubber comprising post-adding a reducing agent in an emulsion polymerization step. The method of any one of claims 22 to 36,
A method for producing acrylic rubber by washing, dehydrating, and drying hydrous crumbs having a particle size of 710 μm to 6.7 mm in a ratio of 50% by weight or more. A rubber composition comprising a rubber component comprising the acrylic rubber according to any one of claims 1 to 21, a filler and a crosslinking agent. 39. The method of claim 38,
A rubber composition wherein the filler is a reinforcing filler. 39. The method of claim 38,
A rubber composition wherein the filler is carbon black. 39. The method of claim 38,
A rubber composition in which the filler is silica. The method of any one of claims 38 to 41,
A rubber composition wherein the crosslinking agent is an organic crosslinking agent. The method of any one of claims 38 to 42,
A rubber composition in which the crosslinking agent is a polyvalent compound. The method of any one of claims 38 to 43,
A rubber composition wherein the cross-linking agent is an ion-crosslinking compound. 45. The method of claim 44,
A rubber composition wherein the cross-linking agent is an ion-crosslinking organic compound. The method of claim 44 or 45,
A rubber composition wherein the crosslinking agent is a polyvalent ionic organic compound. 47. The method of any one of claims 44 to 46,
The rubber composition in which the ion of the ion crosslinkable compound, ion crosslinkable organic compound or polyvalent ion organic compound as the crosslinking agent is at least one ion reactive group selected from the group consisting of an amino group, an epoxy group, a carboxyl group and a thiol group. 47. The method of claim 46,
The rubber composition according to claim 1 , wherein the crosslinking agent is at least one polyvalent ionic compound selected from the group consisting of polyvalent amine compounds, polyvalent epoxy compounds, polyvalent carboxylic acid compounds and polyvalent thiol compounds. The method of any one of claims 38 to 48,
The rubber composition in which the content of the crosslinking agent is in the range of 0.001 to 20 parts by weight based on 100 parts by weight of the rubber component. The method of any one of claims 38 to 49,
A rubber composition further comprising an anti-aging agent. 51. The method of claim 50,
A rubber composition wherein the anti-aging agent is an amine-based anti-aging agent. A method for producing a rubber composition comprising mixing a rubber component comprising the acrylic rubber according to any one of claims 1 to 21, a filler and, if necessary, an antiaging agent, and then mixing a crosslinking agent. A crosslinked rubber product formed by crosslinking the rubber composition according to any one of claims 38 to 51. The method of claim 53,
A crosslinked rubber product in which crosslinking of the rubber composition is performed after molding. The method of claim 53 or 54,
A crosslinked rubber product in which the crosslinking of the rubber composition is performed by primary crosslinking and secondary crosslinking.

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