CN116113646A

CN116113646A - Acrylic rubber bag excellent in Banbury workability and water resistance

Info

Publication number: CN116113646A
Application number: CN202180055476.3A
Authority: CN
Inventors: 增田浩文; 川中孝文
Original assignee: Zeon Corp
Current assignee: Zeon Corp
Priority date: 2020-06-23
Filing date: 2021-06-04
Publication date: 2023-05-12
Also published as: KR20230026335A; WO2021261212A1; WO2021261216A1; CN116034118A; WO2021261214A1; JPWO2021261212A1; WO2021261215A1; KR20230027044A; JPWO2021261214A1; JPWO2021261216A1; JPWO2021261215A1; KR20230027021A; CN116057073A; CN116157424A; KR20230027027A

Abstract

The invention provides an acrylic rubber bag with excellent Banbury processability and water resistance. The acrylic rubber bag of the present invention is formed of an acrylic rubber having an ion-reactive group, the gel amount of methyl ethyl ketone insoluble component is 15 wt% or less, the gel amount of methyl ethyl ketone insoluble component at 20 is arbitrarily measured to be all within the range of (average value + -5 wt%), the pH is 6 or less, the ash content is 0.0005 wt% or more and 0.2 wt% or less, and the total amount of sodium, sulfur, calcium, magnesium and phosphorus in ash is 90 wt% or more.

Description

Acrylic rubber bag excellent in Banbury workability and water resistance

Technical Field

The present invention relates to an acrylic rubber bag, a method for producing the same, a rubber composition and a rubber crosslinked product, and more particularly, to an acrylic rubber bag excellent in banbury workability, strength characteristics, compression set resistance and water resistance, a method for producing the same, a rubber composition comprising the acrylic rubber bag and a rubber crosslinked product obtained by crosslinking the same.

Background

Acrylic rubber is a polymer containing an acrylic ester as a main component, and is generally known as a rubber excellent in heat resistance, oil resistance and ozone resistance, and is widely used in the fields of automobiles and the like.

For example, patent document 1 (Japanese patent application laid-open No. 11-12427) discloses an acrylic rubber and a crosslinking composition which are excellent in extrusion processability and scorch characteristics, wherein 100 parts of a monomer component, 4 parts of sodium lauryl sulfate and 0.25 part of a crosslinking agent

An autoclave replaced with nitrogen, comprising alkyl hydroperoxide, 0.01 part of ferrous sulfate, 0.025 part of sodium ethylenediamine tetraacetate, 0.04 part of sodium formaldehyde sulfoxylate, and 0.01 to 0.05 part of t-dodecyl mercaptan as a chain transfer agent, wherein the monomer components comprise monomers having carbon-carbon double bonds introduced into side chains such as ethyl acrylate, butyl acrylate, methoxyethyl acrylate, acrylonitrile, allyl methacrylate, cyclopentenyloxy ethyl acrylate, and the like, and the reaction is carried out at a reaction temperature of 30 ℃ until the conversion of the monomer mixture reaches 100%, the obtained latex is added to a 0.25% calcium chloride aqueous solution, coagulated, the coagulated mixture is washed with water thoroughly, dried at about 90 ℃ for 3 hours, and crosslinked with an organic peroxide such as 1, 3-bis (t-butylperoxyisopropyl) benzene. However, the acrylic rubber obtained by this method is a pellet-like acrylic rubber, and has problems of poor adhesion and handling efficiency, insufficient banbury workability, injection moldability, storage stability, compression set resistance, water resistance, and strength characteristics.

On the other hand, with respect to the gel-coated acrylic acidFor example, patent document 2 (japanese patent application laid-open No. 2006-328239) discloses a method for producing a rubber polymer, which comprises the steps of: a step of bringing the polymer latex into contact with a coagulating liquid to obtain a pellet slurry containing a pellet-like rubber polymer; with stirring power of 1kW/m ³ The above mixer with stirring and pulverizing functions pulverizes the crumb rubber polymer contained in the crumb slurry; a dehydration step of removing water from the crumb slurry in which the crumb rubber polymer is pulverized to obtain a crumb rubber polymer; and a step of heat-drying the water-removed crumb rubber polymer, wherein the dried crumb is introduced into a baler in a sheet form and compressed to form a bale. The rubber polymer used herein specifically shows an unsaturated nitrile-conjugated diene copolymer latex obtained by emulsion polymerization, and also shows a copolymer composed of only an acrylic ester, such as ethyl acrylate/n-butyl acrylate copolymer, ethyl acrylate/n-butyl acrylate/2-methoxyethyl acrylate copolymer, and the like. However, an acrylic rubber bag composed only of an acrylic ester has a problem of poor properties of crosslinked rubber such as heat resistance and compression set resistance.

As an acrylic rubber having an ion-reactive group and being encapsulated, which is excellent in heat resistance and compression set resistance, for example, patent document 3 (pamphlet of international publication No. 2018/116828) discloses a method for recovering an acrylic rubber as follows: the monomer components comprising ethyl acrylate, n-butyl acrylate and mono-n-butyl fumarate were emulsified with sodium lauryl sulfate, polyethylene glycol monostearate and water as emulsifiers, cumene hydroperoxide as an organic radical generator was added to the emulsion polymerization reaction mixture until the polymerization conversion reached 95%, the thus obtained acrylic rubber latex was added to an aqueous solution of magnesium sulfate and dimethylamine-ammonia-epichlorohydrin polycondensate as a polymer coagulant, followed by stirring at 85℃to give a pellet slurry, and after washing the pellet slurry with water 1 time, all of the slurry was passed through a 100-mesh metal mesh, and only the solid components were collected, whereby the pellet-like acrylic rubber was recovered. This patent document describes that pellets in the aqueous state obtained by this method are dehydrated by centrifugal separation or the like, dried at 50 to 120 ℃ by a belt dryer or the like, introduced into a baler, compressed, and encapsulated. However, this method has a problem that a large amount of aqueous pellets in a semi-coagulated state are generated in the coagulation reaction and adhere to the coagulation tank in large amounts; the problems of coagulants, emulsifiers and the like cannot be sufficiently removed by cleaning; the acrylic rubber itself has problems such as poor banbury processability and injection moldability, insufficient removal of air even when a bag is produced, poor storage stability, and poor water resistance when a crosslinked product is produced by reaction with a crosslinking agent.

Further, regarding the gel amount of an acrylic rubber, for example, patent document 4 (japanese patent No. 3599962) discloses an acrylic rubber composition excellent in extrusion processability such as extrusion speed, die swell (die swell), surface texture and the like, which is composed of an acrylic rubber obtained by copolymerizing 95 to 99.9% by weight of an alkyl acrylate or an alkoxyalkyl acrylate and 0.1 to 5% by weight of a polymerizable monomer having 2 or more radically reactive unsaturated groups having different reactivity in the presence of a radical polymerization initiator, a reinforcing filler and an organic peroxide-based vulcanizing agent, and the percentage of gel which is an acetone insoluble component of the acrylic rubber is 5% by weight or less. The acrylic rubber having a very small gel percentage used herein is obtained by adjusting the pH of a polymerization solution to 6 to 8 with sodium hydrogencarbonate or the like to an acrylic rubber having a high gel percentage (60%) which is obtained in a usual acidic region (pH 4 before polymerization, pH3.4 after polymerization). Specifically, water, sodium lauryl sulfate, polyoxyethylene nonylphenyl ether, sodium carbonate, and boric acid as an emulsifier were added and adjusted to 75 ℃, and then tert-butyl hydroperoxide, sodium formaldehyde sulfoxylate, disodium ethylenediamine tetraacetate, and ferrous sulfate (pH 7.1 in this case) as an organic radical generator were added, followed by dropwise addition of monomer components of ethyl acrylate and allyl methacrylate to perform emulsion polymerization, salting out the obtained emulsion (pH 7) with an aqueous sodium sulfate solution, washing with water, and drying to obtain an acrylic rubber. However, the acrylic rubber containing (meth) acrylic acid ester as a main component is decomposed in a neutral to alkaline region, and even if the processability is improved, there are problems of poor storage stability and strength characteristics, and problems of poor crosslinking property, compression set resistance and water resistance. In addition, the encapsulation of the acrylic rubber is not described in the present specification.

Further, patent document 5 (international publication No. 2018/143101 pamphlet) discloses the following technique: an acrylic rubber having a complex viscosity at 100 ℃ ([ eta ]100 ℃) of 3500 Pa.s or less and a ratio of complex viscosity at 100 ℃ ([ eta ]100 ℃) to complex viscosity at 60 ℃ ([ eta ]60 ℃) ([ eta ]100 ℃/[ eta ]60 ℃) of 0.8 or less is used by emulsion polymerization of a (meth) acrylic ester and an ion-crosslinkable monomer, and the extrusion moldability, particularly the extrusion amount, extrusion length and surface texture of a rubber composition comprising a reinforcing agent and a crosslinking agent are improved. The patent document also describes that the gel amount of the acrylic rubber used as a THF (tetrahydrofuran) insoluble component is 80% by weight or less, preferably 5 to 80% by weight, and preferably as much as possible in the range of 70% or less, and that the extrudability is deteriorated when the gel amount is less than 5%. In addition, it is described that the weight average molecular weight (Mw) of the acrylic rubber used is 200000 ～ 1000000, and when the weight average molecular weight (Mw) exceeds 1000000, the viscoelasticity of the acrylic rubber becomes too high, which is not preferable. However, no method has been described for improving the processability, strength characteristics and water resistance of a Banbury mixer, injection molding or the like.

Prior art literature

Patent literature

Patent document 1: japanese patent laid-open No. 11-12427;

patent document 2: japanese patent laid-open No. 2006-328239;

patent document 3: international publication No. 2018/116828 pamphlet;

patent document 4: japanese patent No. 3599962;

patent document 5: international publication No. 2018/143101.

Disclosure of Invention

Problems to be solved by the invention

The present invention has been made in view of the actual circumstances of the prior art, and an object thereof is to provide an acrylic rubber bag excellent in banbury workability, strength characteristics, compression set resistance and water resistance, a method for producing the same, a rubber composition comprising the acrylic rubber bag, and a crosslinked rubber product obtained by crosslinking the same.

Solution for solving the problem

The present inventors have made intensive studies in view of the above problems, and as a result, have found that an acrylic rubber bag formed of an acrylic rubber having an ion-reactive group, having a specific gel amount of methyl ethyl ketone insoluble component, deviation in gel amount, pH, ash content and ash content, is excellent in banbury workability, strength characteristics, compression set resistance and water resistance.

The present inventors found that, regarding the banbury processability, the smaller the gel amount of the methyl ethyl ketone insoluble component in the acrylic rubber bag, the more excellent. The present inventors have found that the gel amount of methyl ethyl ketone insoluble components in an acrylic rubber bag is generated during the polymerization reaction of acrylic rubber, and particularly when the polymerization conversion rate is increased in order to improve the strength characteristics, the gel amount is drastically increased and is not easily controlled, but can be suppressed to some extent by performing emulsion polymerization in the presence of a chain transfer agent in the latter half of the polymerization reaction; the acrylic rubber is preferably melt kneaded and dried in a screw type biaxial extruder in a state substantially free of moisture by the sharply increased gel amount of the insoluble fraction of the specific solvent, and the banbury processability of the acrylic rubber bag can be remarkably improved with little variation in the gel amount. The present inventors have also found that the banbury processability and the strength characteristics of an acrylic rubber bag produced by melt-kneading and drying in a screw type biaxial extrusion dryer in a state in which water is almost removed (water content less than 1% by weight) are highly balanced.

The present inventors found that the ash content and ash content in the acrylic rubber bag have a large influence on the water resistance. In particular, it has been found that it is quite difficult to remove ash from acrylic rubber produced by using a large amount of an emulsifier or a coagulant, but it has been found that the removal of water by a specific screw type biaxial extrusion dryer can significantly improve the cleaning efficiency of aqueous pellets produced by coagulation by a specific method and the ash removal efficiency at the time of dehydration, significantly reduce the ash content of an acrylic rubber bag, and improve water resistance. The present inventors have found that, particularly, by increasing the ratio of the specific particle size of the aqueous aggregates produced in the coagulation step, washing, dehydrating and drying can significantly improve the water resistance without impairing the properties such as the banbury processability, the strength properties and the compression set resistance of the resulting acrylic rubber bag. Further, the present inventors have found that when a phosphate salt or a sulfate salt is used as an emulsifier and/or an alkali metal salt or a group 2 metal salt of the periodic table is used as a coagulant, the water resistance of the acrylic rubber bag can be remarkably improved, and the injection moldability, the adhesion to metal and the handleability are also reduced, in addition to the ash content and the ash content.

The present inventors have also found that an acrylic rubber bag formed of an acrylic rubber having an ion-reactive group that reacts with a crosslinking agent such as a carboxyl group, an epoxy group, or a chlorine atom, is excellent in normal physical properties including compression set resistance and strength characteristics, and that when the number average molecular weight of the acrylic rubber is within a specific range, the strength characteristics and compression set resistance of the acrylic rubber bag are highly balanced.

The present inventors have found that, in GPC measurement of an ion-reactive acrylic rubber obtained by copolymerizing an ion-reactive group or a monomer containing an ion-reactive group, the radical-reactive acrylic rubber obtained by copolymerizing ethyl acrylate and a dihydrodicyclopentenyl acrylate or the like in the conventional technique cannot be sufficiently dissolved in tetrahydrofuran used in GPC measurement, and each molecular weight and molecular weight distribution cannot be measured perfectly and reproducibly, but can be measured perfectly and reproducibly by using a specific solvent having an SP value higher than that of tetrahydrofuran as an eluting solvent, and the banbury workability, strength characteristics, compression set resistance and water resistance of an acrylic rubber bag can be controlled to a high degree by setting each characteristic value within a specific range.

The present inventors have also found that an acrylic rubber bag having a specific range of the ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of the acrylic rubber can significantly improve injection moldability without impairing the Banbury processability, strength characteristics, compression set resistance and water resistance. The present inventors have also found that an acrylic rubber bag excellent in banbury processability, strength characteristics, compression set resistance and water resistance and also excellent in injection moldability can be produced by emulsifying a monomer component containing an ion-reactive group-containing monomer with water and an emulsifier, then initiating emulsion polymerization in the presence of a redox catalyst composed of an organic radical generator such as dicumyl peroxide and a reducing agent, adding the emulsion polymerization in batch during the polymerization without adding a chain transfer agent in the initial stage, allowing the emulsion polymerization liquid obtained by emulsion polymerization to contact with a coagulant to solidify, and dehydrating, drying and molding the resulting aqueous pellet by a specific screw type biaxial extrusion dryer after washing the solidified aqueous pellet. The number average molecular weight (Mn), the weight average molecular weight (Mw), and the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn) (Mw/Mn) of the acrylic rubber thus produced can be in specific regions, and further, any of the shape formability, the fusion property, and the release property is excellent in terms of injection moldability.

The present inventors have also found that an acrylic rubber bag having a high balance of banbury processability, injection moldability, strength characteristics and compression set resistance can be produced by drying an acrylic rubber using a specific extrusion dryer, and melt-extruding and drying the acrylic rubber under optimum shearing conditions using a specific extrusion dryer, wherein the ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) is widened to some extent without impairing the number average molecular weight (Mn) or the weight average molecular weight (Mw).

The present inventors have also found that an acrylic rubber bag obtained by laminating sheet-like dry rubber obtained by drying under reduced pressure or by melting under reduced pressure and extrusion-drying by a screw-type biaxial extrusion dryer is excellent in banbury workability, strength characteristics, compression set resistance and water resistance and also excellent in storage stability. Since acrylic rubber having a specific ion-reactive group such as carboxyl group, epoxy group and chlorine atom has high affinity for air and is therefore difficult to remove when air is involved, the pellet-like acrylic rubber obtained by directly drying the aqueous pellets involves a large amount of air to deteriorate the storage stability, but the present inventors have found that the storage stability of acrylic rubber can be improved by removing some of the air by packing the pellet-like acrylic rubber by compression with a high-pressure packer or the like, and that it is possible to produce an acrylic rubber bag having very excellent storage stability with little air by drying the aqueous pellets under reduced pressure by a screw type biaxial extrusion dryer and extruding and laminating the aqueous pellets in a sheet form containing no air. The present inventors have also found that the storage stability of the acrylic rubber bag is related to specific gravity which can be measured according to the a method of cross-linked rubber-density measurement using JIS K6268 having a difference in buoyancy, but have found that the acrylic rubber bag subjected to melt kneading and drying under reduced pressure is highly balanced not only in storage stability but also in strength characteristics with processability such as banbury mixer, injection molding and the like. Furthermore, the present inventors found that the pH becomes stable in a specific region for the storage stability of the acrylic rubber bag.

The present inventors have also found that the banbury workability, strength characteristics, compression set resistance and water resistance can be further improved highly by setting the monomer composition of the acrylic rubber, the kind of the ion-reactive group, and the ratio of the complex viscosity at 100 ℃ ([ eta ]100 ℃) to the complex viscosity at 60 ℃ ([ eta ]60 ℃) ([ eta ]100 ℃/[ eta ]60 ℃) and the water content within specific ranges.

The present inventors have found that by using an organic compound having ionic crosslinkability as a crosslinking agent, the crosslinkability is more excellent and each characteristic of the resulting rubber crosslinked product can be significantly improved.

The present inventors have further found that by blending carbon black and silica as fillers in the rubber composition comprising an acrylic rubber bag, a filler and a crosslinking agent of the present invention, the Banbury processability, injection moldability and short-time crosslinking properties are excellent, and the water resistance, strength characteristics and compression set resistance of the crosslinked product are highly excellent. The present inventors have also found that, as the crosslinking agent, an organic compound, a polyvalent compound or an ionic crosslinking compound is preferable, and that by making the crosslinking agent be a polyvalent ionic organic compound having an ion reactive group that reacts with an ion reactive group of an acrylic rubber, such as a plurality of amine groups, epoxy groups, carboxyl groups or thiol groups, for example, banbury processability, injection moldability, crosslinking in a short period of time are excellent, and that the crosslinked product is highly excellent in water resistance, strength characteristics and compression set resistance.

The present inventors have completed the present invention based on these findings.

Therefore, according to the present invention, there can be provided an acrylic rubber bag formed of an acrylic rubber having an ion-reactive group, the gel amount of methyl ethyl ketone insoluble component is 15% by weight or less, the values of the gel amount of methyl ethyl ketone insoluble component at 20 are all in the range of (average ± 5% by weight), the pH is 6 or less, the ash content is 0.0005% by weight or more and 0.2% by weight or less, and the total amount of sodium, sulfur, calcium, magnesium and phosphorus in the ash is 90% by weight or more.

In the acrylic rubber bag of the present invention, it is preferable that the ion-reactive group is 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 bag of the present invention, the specific gravity is preferably 0.8 or more.

In the acrylic rubber bag of the present invention, the ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of the acrylic rubber is preferably in the range of 1 to 25.

In the acrylic rubber bag of the present invention, the ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of the acrylic rubber is preferably in the range of 1.5 to 3.

In the acrylic rubber bag of the present invention, the number average molecular weight (Mn) of the acrylic rubber is preferably in the range of 1 to 300 tens of thousands.

In the acrylic rubber bag of the present invention, the number average molecular weight (Mn) of the acrylic rubber is preferably in the range of 30 to 150 tens of thousands.

In the acrylic rubber bag of the present invention, the solvent for GPC measurement of the weight average molecular weight (Mw) or the number average molecular weight (Mn) of the acrylic rubber is preferably a dimethylformamide-based solvent.

In the acrylic rubber bag of the present invention, the gel amount of the methyl ethyl ketone insoluble component is preferably 5% by weight or less.

In the acrylic rubber bag of the present invention, the ratio of the complex viscosity at 100 ℃ ([ eta ]100 ℃) to the complex viscosity at 60 ℃ ([ eta ]60 ℃) ([ eta ]100 ℃/[ eta ]60 ℃)) is preferably 0.7 or more.

In the acrylic rubber bag of the present invention, the water content is preferably less than 1% by weight.

In the acrylic rubber bag of the present invention, emulsion polymerization is preferably carried out using a phosphate salt or a sulfate salt as an emulsifier.

In the acrylic rubber bag of the present invention, it is preferable to coagulate and dry the emulsion-polymerized polymerization liquid by using an alkali metal salt or a group 2 metal salt of the periodic table as a coagulant.

In the acrylic rubber bag of the present invention, it is preferable to carry out melt kneading and drying after solidification.

In the acrylic rubber bag of the present invention, the above-mentioned melt kneading and drying are preferably carried out in a state substantially free from moisture.

In the acrylic rubber bag of the present invention, the above-mentioned melt kneading and drying are preferably carried out under reduced pressure.

In the acrylic rubber bag of the present invention, it is preferable that the above-mentioned melt-kneading and drying are followed by cooling at a cooling rate of 40℃per hour or more.

In the acrylic rubber bag of the present invention, it is preferable that the acrylic rubber bag is obtained by washing, dehydrating and drying aqueous pellets having a particle diameter in the range of 710 μm to 6.7mm in a proportion of 50% by weight or more.

According to the present invention, there is also provided a method for producing an acrylic rubber bag, comprising the steps of:

an emulsifying step of emulsifying a monomer component composed of a (meth) acrylic acid ester selected from at least one of an alkyl (meth) acrylate and an alkoxyalkyl (meth) acrylate, an ion-reactive group-containing monomer, and other monomers, if necessary, with water and an emulsifier;

an emulsion polymerization step of performing emulsion polymerization in the presence of a redox catalyst comprising a radical generator and a reducing agent to obtain an emulsion polymerization solution;

a coagulation step of bringing the emulsion polymerization liquid obtained into contact with a coagulant to produce an aqueous pellet;

a cleaning step of cleaning the produced water-containing pellets;

A dehydration-drying-molding step of dehydrating the washed aqueous pellets to a water content of 1 to 40 wt% by using a dehydration cylinder having a dehydration slit, a dryer cylinder under reduced pressure, and a screw type biaxial extrusion dryer having a die at the tip, and drying the dehydrated pellets to a water content of less than 1 wt% by using the dryer cylinder, and extruding a sheet-like dried rubber from the die;

a cooling step of cooling the extruded sheet-like dry rubber;

a cutting step of cutting the cooled sheet-like dry rubber; and

and a lamination step of laminating the cut sheet-like dry rubber.

The method for producing an acrylic rubber bag of the present invention is preferably a method for producing an acrylic rubber bag of the present invention.

In the method for producing an acrylic rubber bag of the present invention, it is preferable that in the emulsion polymerization step, a chain transfer agent is added after the polymerization is carried out in batch during the emulsion polymerization, and the polymerization is continued.

In the method for producing an acrylic rubber bag of the present invention, it is preferable that the method for contacting the emulsion polymerization liquid with the coagulant in the coagulation step is a method in which the emulsion polymerization liquid is added to the stirred coagulant.

In the method for producing an acrylic rubber bag of the present invention, it is preferable that in the emulsion polymerization step, emulsion polymerization is carried out using a phosphate salt or a sulfate salt as an emulsifier, and it is preferable that the polymerization liquid produced in the emulsion polymerization step is coagulated by contacting with a coagulant containing an alkali metal salt or a group 2 metal salt of the periodic table.

In the method for producing an acrylic rubber bag of the present invention, it is preferable that the polymerization liquid produced in the emulsion polymerization step is brought into contact with a coagulant, and after the coagulation, the melt-kneading and drying are carried out, and it is preferable that the melt-kneading and drying are carried out in a state of substantially containing no moisture and the melt-kneading and drying are carried out under reduced pressure. Further, the maximum torque of the screw type biaxial extruder at the time of melt kneading and drying is preferably in the range of 5 to 125 N.multidot.m. In the method for producing an acrylic rubber bag of the present invention, it is preferable that the acrylic rubber after melt-kneading and drying is cooled at a cooling rate of 40 ℃/hr or more.

In the method for producing an acrylic rubber bag of the present invention, it is preferable to wash, dehydrate and dry the aqueous pellet having a particle diameter in the range of 710 μm to 6.7mm in a proportion of 50% by weight or more.

In the method for producing an acrylic rubber bag of the present invention, the sheet-like dry rubber in the cutting step preferably has a cutting temperature of 60℃or lower.

In the method for producing an acrylic rubber bag of the present invention, it is preferable that the lamination temperature of the sheet-like dry rubber in the cooling step is 30℃or higher.

Further, according to the present invention, there is provided a rubber composition comprising a rubber component containing the above-mentioned acrylic rubber bag, a filler and a crosslinking agent.

In the rubber composition of the present invention, the filler is preferably a reinforcing filler. In the rubber composition of the present invention, the filler is preferably carbon black. In the rubber composition of the present invention, the filler is preferably silica.

In the rubber composition of the present invention, the crosslinking agent is preferably an organic crosslinking agent. In the rubber composition of the present invention, the crosslinking agent is preferably a polyvalent compound. In the rubber composition of the present invention, it is preferable that the crosslinking agent is an ion-crosslinkable compound. In the rubber composition of the present invention, the crosslinking agent is preferably an ion-crosslinkable organic compound. In the rubber composition of the present invention, the crosslinking agent is preferably a polyionic organic compound.

In the rubber composition of the present invention, it is preferable that the ion of the ion-crosslinkable compound, ion-crosslinkable organic compound or polyion-crosslinkable 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.

In the rubber composition of the present invention, the crosslinking agent is preferably at least one polyion compound selected from the group consisting of a polyamine compound, a polyepoxide compound, a polycarboxylic acid compound and a polythiol compound.

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 relative to 100 parts by weight of the rubber component.

The rubber composition of the present invention preferably further comprises an anti-aging agent. In the rubber composition of the present invention, the antioxidant is preferably an amine-based antioxidant.

Further, according to the present invention, there is provided a method for producing a rubber composition, wherein a rubber component comprising the above-mentioned acrylic rubber, a filler and an anti-aging agent, if necessary, are mixed, and then a crosslinking agent is mixed.

According to the present invention, there is also provided a crosslinked rubber product obtained by crosslinking the above-mentioned rubber composition. In the rubber crosslinked product of the present invention, the crosslinking of the rubber composition is preferably performed after molding. In the rubber crosslinked product of the present invention, it is preferable that the crosslinking of the rubber composition is a crosslinking in which primary crosslinking and secondary crosslinking are performed.

Effects of the invention

According to the present invention, there are provided an acrylic rubber bag excellent in Banbury workability, strength characteristics, compression set resistance and water resistance, an efficient production method therefor, a high-quality rubber composition comprising the acrylic rubber bag, and a crosslinked rubber product obtained by crosslinking the composition.

Drawings

Fig. 1 is a diagram schematically showing an example of an acrylic rubber manufacturing system for manufacturing an acrylic rubber bag according to an embodiment of the present invention.

Fig. 2 is a view showing the structure of the screw extruder of fig. 1.

Fig. 3 is a diagram showing a structure of a transport type cooling device serving as the cooling device of fig. 1.

Detailed Description

The acrylic rubber bag of the present invention is characterized by having an ion-reactive group, being formed from an acrylic rubber having an ion-reactive group, the gel amount of methyl ethyl ketone insoluble component being 15% by weight or less, the gel amount of methyl ethyl ketone insoluble component at 20 being arbitrarily measured being all within the range of (average value.+ -. 5) by weight, the pH being 6 or less, the ash content being 0.0005% by weight or more and 0.2% by weight or less, and the total amount of sodium, sulfur, calcium, magnesium and phosphorus in the ash being 90% by weight or more.

Ion-reactive group >)

The acrylic rubber bag is characterized by having ion reactive groups, and is associated with a crosslinking reaction, so that compression set resistance is improved. The ion-reactive group is not particularly limited as long as it is a functional group involved in an ion reaction, and is appropriately selected according to the purpose of use, and is usually at least one functional group (reactive group) selected from the group consisting of a carboxyl group, an epoxy group and a chlorine atom, and in this case, the compression set resistance of the acrylic rubber bag can be highly improved, and is therefore preferable.

The content of the ion-reactive group in the acrylic rubber bag of the present invention is not particularly limited and may be appropriately selected depending on the purpose of use, but is usually in the range of 0.001 to 5% by weight, preferably 0.01 to 3% by weight, more preferably 0.05 to 1% by weight, and particularly preferably 0.1 to 0.5% by weight, based on the weight of the ion-reactive group itself, and in this case, the processability, crosslinkability, and strength characteristics, compression set resistance, oil resistance, cold resistance, water resistance and the like of the acrylic rubber bag are highly balanced, and thus are preferable.

The acrylic rubber bag having an ion-reactive group of the present invention may be an acrylic rubber bag formed by introducing an ion-reactive group such as a carboxyl group, an epoxy group or a chlorine atom into an acrylic rubber by post-reaction, preferably an acrylic rubber bag formed by copolymerizing an ion-reactive group-containing monomer.

< monomer component >

The monomer components of the acrylic rubber constituting the acrylic rubber bag of the present invention are not particularly limited, and may be appropriately selected depending on the purpose of use, and when composed of at least one (meth) acrylate selected from the group consisting of alkyl (meth) acrylates and alkoxyalkyl (meth) acrylates, an ion-reactive group-containing monomer, and other copolymerizable monomers, if necessary, the properties such as crosslinking property, compression set resistance, weather resistance, heat resistance, and oil resistance in a short period of time are highly balanced, and thus are preferable. In addition, in the present invention, "(meth) acrylate" is used as a term for esters of acrylic acid and/or methacrylic acid.

The alkyl (meth) acrylate is not particularly limited, and an alkyl (meth) acrylate having an alkyl group having 1 to 12 carbon atoms is usually used, and an alkyl (meth) acrylate having an alkyl group having 1 to 8 carbon atoms is preferably used, and an alkyl (meth) acrylate having an alkyl group having 2 to 6 carbon atoms is more preferably used.

Specific examples of the alkyl (meth) acrylate include: methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, n-hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, cyclohexyl (meth) acrylate, and the like, wherein ethyl (meth) acrylate, n-butyl (meth) acrylate, more preferably ethyl acrylate, and n-butyl acrylate are preferred.

The alkoxyalkyl (meth) acrylate is not particularly limited, and an alkoxyalkyl (meth) acrylate having an alkoxyalkyl group having 2 to 12 carbon atoms is usually used, and an alkoxyalkyl (meth) acrylate having an alkoxyalkyl group having 2 to 8 carbon atoms is preferably used, and an alkoxyalkyl (meth) acrylate having an alkoxyalkyl group having 2 to 6 carbon atoms is more preferably used.

Specific examples of the alkoxyalkyl (meth) acrylate include: methoxymethyl (meth) acrylate, methoxyethyl (meth) acrylate, methoxypropyl (meth) acrylate, methoxybutyl (meth) acrylate, ethoxymethyl (meth) acrylate, ethoxyethyl (meth) acrylate, propoxyethyl (meth) acrylate, butoxyethyl (meth) acrylate, and the like. Among these, methoxyethyl (meth) acrylate, ethoxyethyl (meth) acrylate, and the like are preferable, and methoxyethyl acrylate and ethoxyethyl acrylate are more preferable.

These at least one (meth) acrylic acid ester selected from the group consisting of alkyl (meth) acrylates and alkoxyalkyl (meth) acrylates may be used singly or in combination, and the proportion thereof in the whole monomer components is usually in the range of 50 to 99.99% by weight, preferably in the range of 62 to 99.95% by weight, more preferably in the range of 74 to 99.9% by weight, particularly preferably in the range of 80 to 99.5% by weight, most preferably in the range of 87 to 99% by weight, and in this case, the acrylic rubber package is highly excellent in weather resistance, heat resistance and oil resistance, and therefore is preferred.

The ion-reactive group-containing monomer is not particularly limited as long as it has a functional group that participates in an ion reaction, and may be appropriately selected depending on the purpose of use, and generally, a monomer having at least one functional group (reactive group) selected from a carboxyl group, an epoxy group and a chlorine atom is preferable, and a monomer having a carboxyl group and an epoxy group is more preferable, and in this case, the crosslinking property in a short period of time of the acrylic rubber coating, the compression set resistance and the water resistance of the crosslinked product can be highly improved, and therefore, it is preferable.

The monomer having a carboxyl group is not particularly limited, and an ethylenically unsaturated carboxylic acid can be preferably used. Examples of the ethylenically unsaturated carboxylic acid include ethylenically unsaturated monocarboxylic acid, ethylenically unsaturated dicarboxylic acid, and ethylenically unsaturated dicarboxylic acid monoester, and among these, ethylenically unsaturated dicarboxylic acid monoester is particularly preferable because it can further improve compression set resistance when the acrylic rubber is coated into a rubber crosslinked product.

The ethylenically unsaturated monocarboxylic acid is not particularly limited, but preferably has 3 to 12 carbon atoms, and examples thereof include acrylic acid, methacrylic acid, α -ethylacrylic acid, crotonic acid, cinnamic acid, and the like.

The ethylenically unsaturated dicarboxylic acid is not particularly limited, but an ethylenically unsaturated dicarboxylic acid having 4 to 12 carbon atoms is preferable, and examples thereof include butenedioic acid such as fumaric acid and maleic acid, itaconic acid and citraconic acid. In addition, ethylenically unsaturated dicarboxylic acids also include ethylenically unsaturated dicarboxylic acids in the form of anhydrides.

The ethylenically unsaturated dicarboxylic acid monoester is not particularly limited, and examples thereof include alkyl monoesters having 1 to 12 carbon atoms of ethylenically unsaturated dicarboxylic acids having 4 to 12 carbon atoms, preferably alkyl monoesters having 2 to 8 carbon atoms of ethylenically unsaturated dicarboxylic acids having 4 to 6 carbon atoms, and more preferably alkyl monoesters having 2 to 6 carbon atoms of butenedioic acid having 4 carbon atoms.

Specific examples of the ethylenically unsaturated dicarboxylic acid monoester include: mono-alkyl butenedioates such as monomethyl fumarate, monoethyl fumarate, mono-n-butyl fumarate, monomethyl maleate, monoethyl maleate, mono-n-butyl maleate, monocyclopentyl fumarate, monocyclohexyl fumarate, monocyclohexenyl fumarate, monocyclopentyl maleate, monocyclohexyl maleate, and the like; mono-alkyl itaconates such as monomethyl itaconate, monoethyl itaconate, mono-n-butyl itaconate and monocyclohexyl itaconate, and among these, mono-n-butyl fumarate and mono-n-butyl maleate are preferable, and mono-n-butyl fumarate is particularly preferable.

Examples of the monomer having an epoxy group include: epoxy group-containing (meth) acrylates such as glycidyl (meth) acrylate; vinyl ethers containing an epoxy group such as allyl glycidyl ether and vinyl glycidyl ether.

The monomer having a chlorine atom is not particularly limited, and examples thereof include: unsaturated alcohol esters of saturated carboxylic acids having chlorine atoms, chloroalkyl (meth) acrylates, chloroacyloxy alkyl (meth) acrylates, (chloroacetylcarbamooxy) alkyl (meth) acrylates, unsaturated ethers having chlorine atoms, unsaturated ketones having chlorine atoms, aromatic vinyl compounds having chlorine methyl groups, unsaturated amides having chlorine atoms, unsaturated monomers having chlorine acetyl groups, and the like.

Specific examples of the unsaturated alcohol ester of a saturated carboxylic acid containing a chlorine atom include vinyl chloroacetate, vinyl 2-chloropropionate, allyl chloroacetate, and the like. Specific examples of the chloroalkyl (meth) acrylate 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 the chloroacetoxy alkyl (meth) acrylate include 2- (chloroacetoxy) ethyl (meth) acrylate, 2- (chloroacetoxy) propyl (meth) acrylate, 3- (chloroacetoxy) propyl (meth) acrylate, and 3- (hydroxychloroacetoxy) propyl (meth) acrylate. Examples of the (chloroacetylcarbamoyloxy) alkyl (meth) acrylate include 2- (chloroacetylcarbamoyloxy) ethyl (meth) acrylate and 3- (chloroacetylcarbamoyloxy) propyl (meth) acrylate. Specific examples of the unsaturated ether containing chlorine atoms 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 unsaturated ketone containing chlorine atoms include 2-chloroethyl vinyl ketone, 3-chloropropyl vinyl ketone, and 2-chloroethyl allyl ketone. Specific examples of the chloromethyl-containing aromatic vinyl compound include p-chloromethylstyrene, m-chloromethylstyrene, o-chloromethylstyrene, p-chloromethyl- α -methylstyrene, and the like. Specific examples of the unsaturated amide containing chlorine atom include N-chloromethyl (meth) acrylamide and the like. Specific examples of the chloracetyl-containing unsaturated monomer include 3- (hydroxychloroacetoxy) propyl allyl ether, p-vinylbenzyl chloroacetate, and the like.

These ion-reactive group-containing monomers may be used singly or in combination, and the proportion thereof in the total monomer components is usually in the range of 0.01 to 10% by weight, preferably 0.05 to 8% by weight, more preferably 0.1 to 6% by weight, particularly preferably 0.5 to 5% by weight, and most preferably 1 to 3% by weight.

The monomer other than the above (simply referred to as "other monomer" in the present invention) that can be used together with the above-described monomers as needed is not particularly limited as long as it is a monomer copolymerizable with the above-described monomer, and examples thereof include: aromatic vinyl groups such as styrene, α -methylstyrene, divinylbenzene, and the like; ethylenically unsaturated nitriles such as acrylonitrile and methacrylonitrile; acrylamide monomers such as acrylamide and methacrylamide; olefin monomers such as ethylene, propylene, vinyl acetate, ethyl vinyl ether, butyl vinyl ether, and the like.

These other monomers may be used singly or in combination, and the ratio thereof in the total monomer components is usually controlled to be in the range of 0 to 40% by weight, preferably 0 to 30% by weight, more preferably 0 to 20% by weight, particularly preferably 0 to 15% by weight, and most preferably 0 to 10% by weight.

Acrylic rubber >, a rubber composition

The acrylic rubber constituting the acrylic rubber bag of the present invention is characterized by having the above-mentioned ion-reactive group, preferably being composed of the above-mentioned monomer component, and having a weight average molecular weight (Mw), a number average molecular weight (Mn), a ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn), and the like in specific ranges.

The monomer constituting the acrylic rubber of the acrylic rubber bag of the present invention is composed of a combination unit derived from at least one (meth) acrylate selected from the group consisting of alkyl (meth) acrylate and alkoxyalkyl (meth) acrylate, an ion-reactive group-containing monomer, and other monomers as required, and their respective proportions in the acrylic rubber are as follows: the binding unit derived from at least one (meth) acrylate selected from the group consisting of alkyl (meth) acrylates and alkoxyalkyl (meth) acrylates is generally in the range of 50 to 99.99 wt%, preferably 62 to 99.95 wt%, more preferably 74 to 99.9 wt%, particularly preferably 80 to 99.5 wt%, most preferably 87 to 99 wt%; the binding units derived from the ion-reactive group-containing monomer are generally in the range of 0.01 to 10% by weight, preferably 0.05 to 8% by weight, more preferably 0.1 to 6% by weight, particularly preferably 0.5 to 5% by weight, most preferably 1 to 3% by weight; the binding unit derived from the other monomer is usually in the range of 0 to 40% by weight, preferably 0 to 30% by weight, more preferably 0 to 20% by weight, particularly preferably 0 to 15% by weight, most preferably 0 to 10% by weight. When the monomer composition of the acrylic rubber is within this range, the acrylic rubber bag is preferable because the properties such as short-time crosslinkability, compression set resistance, weather resistance, heat resistance, and oil resistance are highly balanced.

The number average molecular weight (Mn) of the acrylic rubber constituting the acrylic rubber package of the present invention is not particularly limited, and is usually in the range of 1 to 300 tens of thousands, preferably 1.5 to 250 tens of thousands, more preferably 2 to 200 tens of thousands. If the number average molecular weight (Mn) of the acrylic rubber constituting the acrylic rubber bag is too small, the strength characteristics and compression set resistance are poor, whereas if the number average molecular weight is too large, the banbury processability is poor, which is not preferable. The number average molecular weight (Mn) of the acrylic rubber constituting the acrylic rubber bag of the present invention is usually in the range of 30 to 150 tens of thousands, preferably 35 to 130 tens of thousands, more preferably 40 to 110 tens of thousands, particularly preferably 50 to 100 tens of thousands, most preferably 55 to 75 tens of thousands, and at this time, the banbury processability, injection moldability, strength characteristics and compression set resistance of the acrylic rubber bag are highly balanced, and therefore, it is preferable.

The weight average molecular weight (Mw) of the acrylic rubber constituting the acrylic rubber package of the present invention is not particularly limited, and is usually in the range of 10 to 1000 tens of thousands, preferably 20 to 800 tens of thousands, more preferably 25 to 750 tens of thousands, particularly preferably 30 to 600 tens of thousands, and most preferably 50 to 550 tens of thousands. If the weight average molecular weight (Mw) of the acrylic rubber constituting the acrylic rubber bag is too small, the strength characteristics and compression set resistance of the acrylic rubber bag are poor, whereas if the weight average molecular weight is too large, the banbury processability is poor, which is not preferable. The weight average molecular weight (Mw) of the acrylic rubber constituting the acrylic rubber bag of the present invention is usually in the range of 100 to 500 tens of thousands, preferably 110 to 400 tens of thousands, more preferably 120 to 300 tens of thousands, particularly preferably 150 to 250 tens of thousands, most preferably 160 to 220 tens of thousands, and at this time, the Banbury processability, injection moldability, strength characteristics, and compression set resistance of the acrylic rubber bag are highly balanced, and therefore, it is preferable.

The z-average molecular weight (Mz) of the acrylic rubber constituting the acrylic rubber bag of the present invention is not particularly limited, and may be appropriately selected depending on the purpose of use, and is usually 150 ten thousand or more, preferably 200 ten thousand or more, more preferably 250 ten thousand or more, and particularly preferably 300 ten thousand or more. The z-average molecular weight (Mz) of the acrylic rubber constituting the acrylic rubber bag of the present invention is preferably in the range of from 150 to 600 tens of thousands, preferably from 180 to 550 tens of thousands, more preferably from 200 to 500 tens of thousands, particularly preferably from 220 to 450 tens of thousands, and most preferably from 250 to 400 tens of thousands, and at this time, the injection moldability, banbury processability, strength characteristics, and compression set resistance of the acrylic rubber bag are highly balanced, and therefore preferred.

The ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of the acrylic rubber constituting the acrylic rubber package of the present invention is not particularly limited, and is usually in the range of 1 to 25, preferably 1.1 to 20, more preferably 1.2 to 15, particularly preferably 1.3 to 10. If the ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of the acrylic rubber constituting the acrylic rubber bag is too small, the strength characteristics and compression set resistance of the acrylic rubber bag are poor, whereas if too large, the Banbury workability is poor, 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 constituting the acrylic rubber bag of the present invention is generally in the range of 1.5 to 3, preferably 1.8 to 2.7, more preferably 2 to 2.6, and particularly preferably 2.2 to 2.6, and in this case, the injection moldability, banbury processability and strength characteristics at the time of crosslinking, and compression set resistance of the acrylic rubber bag are highly balanced, and therefore, are preferable. In particular, when the ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of the acrylic rubber constituting the acrylic rubber bag of the present invention is within this range, all the properties of the shape formability, fusion property and release property of the acrylic rubber bag for injection molding are excellent, and the strength property as a crosslinked product and compression set resistance are also highly balanced, so that it is preferable.

The molecular weight distribution of the acrylic rubber constituting the acrylic rubber package of the present invention is not particularly limited, and is usually 1.3 or more, preferably 1.4 or more, more preferably 1.5 or more, particularly preferably 1.6 or more, and most preferably 1.7 or more, in terms of the ratio (Mz/Mw) of the z-average molecular weight (Mz) to the weight-average molecular weight (Mw), and in this case, the deterioration of the releasability and the shape formability (occurrence of burrs) when the weight-average molecular weight (Mw) becomes too small can be prevented. The acrylic rubber constituting the acrylic rubber bag of the present invention is also preferably because the molecular weight distribution (Mz/Mw) focusing on the high molecular weight region is usually 4 or less, preferably 3 or less, more preferably 2.5 or less, particularly preferably 2.2 or less, and most preferably 2 or less, and in this case, deterioration in shape formability (insufficient shape) and fusion properties when the weight average molecular weight (Mw) becomes excessively large can be prevented. The acrylic rubber constituting the acrylic rubber bag of the present invention is more preferably such that the molecular weight distribution (Mz/Mw) focusing on the high molecular weight region is further usually in the range of 1.3 to 3, preferably 1.4 to 2.5, more preferably 1.5 to 2.2, particularly preferably 1.6 to 2, and most preferably 1.7 to 1.9, and in this case, the injection moldability and banbury processability can be improved to a high degree without impairing the strength characteristics of the acrylic rubber bag.

The measurement of the molecular weight (Mn, mw, mz) and the molecular weight distribution (Mw/Mn, mz/Mw) of the acrylic rubber constituting the acrylic rubber package of the present invention is not particularly limited, and it is preferable to obtain each characteristic more accurately when the absolute molecular weight (Mn, mw, mz) and the absolute molecular weight distribution (Mw/Mn, mz/Mw) are measured by GPC-MALS method.

The measuring solvent used in the GPC-MALS method for measuring the molecular weight (Mn, mw, mz) and the molecular weight distribution (Mw/Mn, mz/Mw) of the acrylic rubber constituting the acrylic rubber bag of the present invention is not particularly limited as long as it is a solvent capable of dissolving and measuring the acrylic rubber bag of the present invention, and a dimethylformamide-based solvent is preferable. The dimethylformamide-based solvent to be used is not particularly limited as long as it is a solvent containing dimethylformamide as a main component, and dimethylformamide may be used as 100% or a polar substance may be added to dimethylformamide. The proportion of dimethylformamide in the dimethylformamide-based solvent is 90% by weight or more, preferably 95% by weight or more, and more preferably 97% by weight or more. In the present invention, lithium chloride and 37% concentrated hydrochloric acid are preferably added to dimethylformamide, respectively, so that the concentration of lithium chloride is 0.05mol/L and the concentration of hydrochloric acid is 0.01%.

The glass transition temperature (Tg) of the acrylic rubber constituting the acrylic rubber bag of the present invention can be appropriately selected depending on the purpose of use of the acrylic rubber, and is usually 20 ℃ or less, preferably 10 ℃ or less, more preferably 0 ℃ or less, and in this case, processability and cold resistance are excellent, and therefore, it is preferable. The lower limit of the glass transition temperature (Tg) of the acrylic rubber is not particularly limited, but is usually-80℃or higher, preferably-60℃or higher, and more preferably-40℃or higher. The oil resistance and heat resistance of the acrylic rubber bag can be further improved by setting the glass transition temperature to the above lower limit or more, and the processability, crosslinking property and cold resistance of the acrylic rubber bag can be further improved by setting the glass transition temperature to the above upper limit or less.

Acrylic rubber bag

The acrylic rubber bag of the present invention is characterized in that it is formed of the acrylic rubber, the gel amount of the methyl ethyl ketone insoluble component is 15 wt% or less, the gel amount of the methyl ethyl ketone insoluble component at 20 is arbitrarily measured to be all within the range of (average value.+ -. 5 wt%), the pH is 6 or less, the ash content is 0.0005 wt% or more and 0.2 wt% or less, and the total amount of sodium, sulfur, calcium, magnesium and phosphorus in ash is 90 wt% or more.

The gel amount of the methyl ethyl ketone insoluble component in the acrylic rubber bag of the present invention is preferably 15 wt% or less, more preferably 13 wt% or less, still more preferably 10 wt% or less, particularly preferably 7 wt% or less, and most preferably 5 wt% or less, and in this case, the processability and injection moldability in kneading by a Banbury mixer or the like are improved to a high degree.

The gel amount of the methyl ethyl ketone insoluble component of the acrylic rubber composition of the present invention was arbitrarily measured at 20 points and was as follows: the values at 20 are all in the range of (average value.+ -. 5) wt%, and the values at 20 are preferably all in the range of (average value.+ -. 3) wt%, and in this case, there is no deviation in processability, and the physical properties of the rubber composition and the rubber crosslinked product are stabilized, so that it is preferable. The values at 20 when the gel amount of the acrylic rubber bag is arbitrarily measured are all within the range of ±5 of the average value, which means that the measured gel amounts at 20 are all within the range of (average value-5) to (average value +5) wt%, for example, when the average value of the measured gel amounts is 20 wt%, the measured values at 20 are all within the range of 15 to 25 wt%.

The acrylic rubber bag of the present invention is preferably obtained by melt-kneading and drying an acrylic rubber in a screw type biaxial extruder with almost water removed, and in this case, the banbury processability and strength characteristics of the acrylic rubber bag are highly balanced.

The pH of the acrylic rubber bag of the present invention is preferably in the range of 2 to 6, more preferably 2.5 to 5.5, and most preferably 3 to 5, because the storage stability of the acrylic rubber bag is highly improved.

The lower limit of the ash content of the acrylic rubber bag of the present invention is 0.0001 wt% or more, preferably 0.0005 wt% or more, more preferably 0.001 wt% or more, particularly preferably 0.005 wt% or more, and most preferably 0.01 wt% or more. When the ash content of the acrylic rubber bag is within this range, the metal adhesion of the rubber is reduced, the handling property is excellent, and the injection moldability, particularly the release property is excellent, so that it is preferable.

The upper limit of the ash content of the acrylic rubber bag of the present invention is 0.2 wt% or less, preferably 0.19 wt% or less, more preferably 0.18 wt% or less, particularly preferably 0.15 wt% or less, and most preferably 0.13 wt% or less. When the ash content of the acrylic rubber bag is within this range, the water resistance, storage stability, strength characteristics, processability and fusion properties of injection moldability are highly balanced, and thus are preferable.

The ash content of the acrylic rubber bag of the present invention in the case of highly balancing the water resistance, storage stability, strength characteristics, processability, handleability and fusion property of injection moldability and release property is usually in the range of 0.0001 to 0.3% by weight, preferably 0.0005 to 0.2% by weight, more preferably 0.001 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 bag of the present invention is preferably 90% by weight or more, more preferably 93% by weight or more, and still more preferably 95% by weight or more, and in this case, the water resistance, the fusion property by injection molding and the release property of the acrylic rubber bag are highly improved.

The total amount of magnesium and phosphorus in ash of the acrylic rubber bag 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, particularly preferably 80% by weight or more, and most preferably 90% by weight or more, and in this case, the water resistance, strength characteristics, fusion property and releasability of injection molding, and workability of the acrylic rubber bag are highly balanced, and thus are preferable.

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

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

The ratio of magnesium to phosphorus ([ Mg ]/[ P ]) in ash of the acrylic rubber bag of the present invention is not particularly limited, and may be appropriately selected depending on the purpose of use, and is usually in the range of 0.4 to 2.5, preferably 0.45 to 1.2, more preferably 0.45 to 1, particularly preferably 0.5 to 0.8, most preferably 0.55 to 0.7 in terms of weight ratio, and in this case, the water resistance, strength characteristics, fusion and release properties of injection molding and workability of the acrylic rubber bag are highly balanced, and thus are preferable.

Here, the ash in the acrylic rubber bag mainly comes from an emulsifier used in emulsion polymerization by emulsifying a monomer component and a coagulant used in coagulating an emulsion polymerization liquid, but the total ash amount, the content of magnesium and phosphorus in ash, and the like vary not only depending on the conditions of the emulsion polymerization step and the coagulation step but also depending on the conditions of the subsequent steps.

In order to highly balance the water resistance, strength characteristics, fusion property and release property of injection molding, and processability of the acrylic rubber bag, in particular, as an emulsifier in emulsion polymerization of acrylic rubber, an anionic emulsifier, a cationic emulsifier, or a nonionic emulsifier, which will be described later, is used, preferably an anionic emulsifier, and more preferably a phosphate or sulfate salt. The water resistance of the acrylic rubber bag is mainly related to the ash content in the acrylic rubber and the total amount of sodium, magnesium, calcium, phosphorus and sulfur in the ash, and when the above-mentioned emulsifier is used, the water resistance, strength characteristics, fusion property and release property and processability of the acrylic rubber bag by injection molding can be more highly balanced, so that it is preferable.

In order to highly balance the water resistance, strength characteristics, fusion and release properties of injection molding, and workability of the acrylic rubber bag, in particular, a metal salt described later, preferably an alkali metal salt or a group 2 metal salt of the periodic table is used as the coagulant. The water resistance of the acrylic rubber is mainly related to the ash content in the acrylic rubber and the total amount of sodium, magnesium, calcium, phosphorus and sulfur in the ash, and when the coagulant is used, the water resistance, strength characteristics, fusion property and release property and processability of the acrylic rubber bag can be more highly balanced, so that it is preferable.

The complex viscosity ([ eta ]100 ℃) of the acrylic rubber bag of the present invention at 100℃is not particularly limited, and may be appropriately selected depending on the purpose of use, but is usually not more than 15000[ Pa.s ], preferably 1000 to 10000[ Pa.s ], more preferably 2000 to 8000[ Pa.s ], particularly preferably 3000 to 5000[ Pa.s ], and most preferably 3500 to 4000[ Pa.s ], and in this case, processability, oil resistance, injection moldability and shape retention are excellent, and therefore, they are preferable.

The ratio of the complex viscosity at 100 ℃ ([ eta ]100 ℃) to the complex viscosity at 60 ℃ ([ eta ]60 ℃) ([ eta ]100 ℃/[ eta ]60 ℃) of the acrylic rubber package of the present invention is not particularly limited, and is appropriately selected depending on the purpose of use, and is usually 0.5 or more, preferably 0.6 or more, more preferably 0.7 or more. In addition, the ratio of the complex viscosity at 100 ℃ ([ eta ]100 ℃) to the complex viscosity at 60 ℃ ([ eta ]60 ℃) ([ eta ]100 ℃/[ eta ]60 ℃) of the acrylic rubber package of the present invention is usually in the range of 0.5 to 0.99, preferably 0.55 to 0.95, more preferably 0.6 to 0.9, particularly preferably 0.65 to 0.85, most preferably 0.7 to 0.8, and in this case, the processability, oil resistance and shape retention are highly balanced, and therefore preferred.

The specific gravity of the acrylic rubber bag of the present invention is not particularly limited, but is usually 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, and in this case, air is hardly present in the interior and the storage stability is excellent, and therefore, it is preferable. The specific gravity of the acrylic rubber bag of the present invention is preferably 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, and in this case, productivity, storage stability, crosslinking property stability of the crosslinked product, and the like are highly balanced. When the specific gravity of the acrylic rubber bag is too small, it is not preferable because a large amount of air in the acrylic rubber bag has a great influence on the storage stability including oxidative deterioration and the like.

The specific gravity of the acrylic rubber of the present invention is a value obtained by dividing the mass by the volume including voids, that is, the mass measured in air by the buoyancy, and is usually measured according to the method a of JIS K6268 crosslinked rubber-density measurement.

In addition, in the acrylic rubber bag of the present invention, the acrylic rubber bag obtained by drying the acrylic rubber under reduced pressure by a screw type biaxial extrusion dryer or by melting and extrusion drying under reduced pressure is particularly excellent in storage stability, injection moldability and strength characteristics and is highly balanced, and therefore is preferable.

The water content of the acrylic rubber bag of the present invention is not particularly limited, and may be appropriately selected depending on the purpose of use, but is usually less than 1% by weight, preferably 0.8% by weight or less, more preferably 0.6% by weight or less, and in this case, the vulcanization characteristics of the acrylic rubber bag are optimized, and the characteristics such as heat resistance and water resistance are highly improved, and therefore, it is preferable.

The Mooney viscosity (ML1+4, 100 ℃) of the acrylic rubber bag of the present invention is not particularly limited, and may be appropriately selected depending on the purpose of use, and is usually in the range of 10 to 150, preferably 20 to 100, more preferably 25 to 70, and in this case, the processability and strength characteristics of the acrylic rubber bag are highly balanced, and thus preferable.

The size of the acrylic rubber bag of the present invention is not particularly limited, and may be appropriately selected depending on the purpose of use, and the width is usually in the range of 100 to 800mm, preferably 200 to 500mm, more preferably 250 to 450mm, the length is usually in the range of 300 to 1200mm, preferably 400 to 1000mm, more preferably 500 to 800mm, and the height (thickness) is usually in the range of 50 to 500mm, preferably 100 to 300mm, more preferably 150 to 250 mm. The shape of the acrylic rubber bag of the present invention is not particularly limited, and may be appropriately selected depending on the purpose of use of the acrylic rubber bag, and in many cases, a rectangular parallelepiped is preferable.

Method for producing acrylic rubber bag

The method for producing the acrylic rubber bag of the present invention is not particularly limited, and for example, the acrylic rubber bag can be produced efficiently by a production method comprising the steps of:

an emulsifying step of emulsifying a monomer component composed of at least one (meth) acrylic acid ester selected from the group consisting of alkyl (meth) acrylates and alkoxyalkyl (meth) acrylates, an ion-reactive group-containing monomer, and other monomers used as needed, with water and an emulsifier;

a cleaning step of cleaning the produced water-containing pellets;

a dehydration, drying and molding step of dehydrating the washed aqueous pellets to a water content of 1 to 40 wt% by using a dehydration cylinder having a dehydration slit, a drying cylinder under reduced pressure and a screw type biaxial extrusion dryer having a die at the tip, and then drying the pellets to a water content of less than 1 wt% by using the drying cylinder, and extruding a sheet-like dried rubber from the die;

A cooling step of cooling the extruded sheet-like dry rubber;

a cutting step of cutting the cooled sheet-like dry rubber; and

and a lamination step of laminating the cut sheet-like dry rubber.

(emulsification Process)

The emulsification step in the method for producing an acrylic rubber bag of the present invention is a step of emulsifying a monomer component composed of at least one (meth) acrylate selected from the group consisting of alkyl (meth) acrylates and alkoxyalkyl (meth) acrylates, an ion-reactive group-containing monomer, and other monomers used as needed, with water and an emulsifier.

(monomer component)

The monomer component used in the present invention is composed of at least one (meth) acrylate selected from the group consisting of alkyl (meth) acrylates and alkoxyalkyl (meth) acrylates, an ion-reactive group-containing monomer, and other copolymerizable monomers, if necessary, and the same ranges as exemplified and preferred for the above-mentioned monomer components. The amount of the monomer component used is also as described above, and in emulsion polymerization, each monomer may be appropriately selected so as to be the above-described composition of the acrylic rubber constituting the acrylic rubber bag of the present invention.

(emulsifier)

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

The anionic emulsifier is not particularly limited, and examples thereof include: salts of fatty acids such as myristic acid, palmitic acid, oleic acid, and linolenic acid; alkylbenzene sulfonates such as sodium dodecylbenzene sulfonate; sulfate salts such as sodium lauryl sulfate, phosphate salts such as polyoxyalkylene alkyl ether phosphate salts; alkyl sulfosuccinates, and the like. Among these anionic emulsifiers, phosphate salts and sulfate salts are preferable, phosphate salts are particularly preferable, and dibasic phosphate salts are most preferable, and in this case, the water resistance, strength characteristics, fusion property and release property of the resulting acrylic rubber bag, and processability can be highly balanced. The phosphate and sulfate are preferably alkali metal salts of phosphate and sulfate, and more preferably sodium salts of phosphate and sulfate, and in this case, the water resistance, strength characteristics, mold release properties and workability of the obtained acrylic rubber bag can be highly balanced.

The dibasic phosphate is not particularly limited as long as it can be used as an emulsifier in emulsion polymerization, and examples thereof include alkoxypolyoxyalkylene phosphate and alkylphenoxypolyoxyalkylene phosphate, and among these, metal salts thereof are preferable, alkali metal salts thereof are more preferable, and sodium salts thereof are most preferable.

Examples of the alkoxypolyoxyalkylene phosphate include: among these, alkoxypolyoxyethylene phosphate salts are preferable, such as alkoxypolyoxyethylene phosphate salts and alkoxypolyoxypropylene phosphate salts.

As specific examples of the alkoxypolyoxyethylene phosphate salt, there may be mentioned octyloxydioxyethylene phosphate, octyloxytrioxyethylene phosphate, octyloxytetraethylene phosphate, decyloxy tetraethylene phosphate, dodecyloxytetraethylene phosphate, tridecyloxytetraethylene phosphate, tetradecyloxy tetraethylene phosphate, hexadecyloxy tetraethylene phosphate, octadecyl tetraethylene phosphate, octyloxypentaethylene phosphate, decyloxy pentaethylene phosphate, dodecyloxypentaethylene phosphate, tridecyloxypentaethylene phosphate, tetradecyloxy pentaethylene phosphate, hexadecyloxy pentaethylene phosphate, octadecyl pentaethylene phosphate, octyloxyhexaethylene phosphate, decyloxy hexaethylene phosphate, dodecyloxyhexaethylene phosphate, tridecyloxyhexaethylene phosphate, tetradecyloxy hexaethylene phosphate, hexadecyloxy hexaethylene phosphate, octadecyl hexaethylene phosphate, octooxyoctaethylene phosphate, dodecyloxyoctaethylene phosphate, tridecyloxyoctaethylene phosphate, and octaalkoxyoctaethylene phosphate, especially among these, sodium salts of the metal, are preferable.

Specific examples of the alkoxypolyoxypropylene phosphate include octyloxydioxy-propylene phosphate, octyloxytrioxypropylene phosphate, octyloxytetraoxypropylene phosphate, decyloxy-tetrapropoxy-phosphate, dodecyloxytetrapropoxy-phosphate, tridecyloxytetrapropoxy-phosphate, tetradecyloxy-tetrapropoxy-phosphate, hexadecyloxy-tetrapropoxy-phosphate, octadecyloxypropy-phosphate, octyloxypentaoxypropy-phosphate, decyloxy-pentapropy-phosphate, dodecyloxypentaoxypropy-phosphate, tridecyloxypentaoxypropy-phosphate, tetradecyloxy-pentapropy-phosphate, hexadecyloxy-pentapropy-phosphate, octadecyloxypentaoxypropy-phosphate, octyloxypropy-phosphate, decyloxy-hexaoxypropy-phosphate, dodecyloxypropy-phosphate, tridecyloxypropy-phosphate, tetradecyloxy-hexaoxypropy-phosphate, hexadecyloxy-hexaoxypropy-phosphate, octadecyloxypropy-phosphate, dodecyloxypropy-phosphate, tridecyloxypropy-octaoxypropy-phosphate, octaalkoxyl-phosphate, and their alkali metal salts, especially preferred among these are sodium salts.

Specific examples of the alkylphenoxy polyoxyalkylene phosphate include alkylphenoxy polyoxyethylene phosphate and alkylphenoxy polyoxypropylene phosphate, and of these, alkylphenoxy polyoxyethylene phosphate is preferred.

Specific examples of the alkylphenoxypolyoxyethylene phosphate salt include metal salts such as methylphenoxy tetraoxyethylene phosphate, ethylphenoxytetraoxyethylene phosphate, butylphenoxy tetraoxyethylene phosphate, hexylphenoxy tetraoxyethylene phosphate, nonylphenoxy tetraoxyethylene phosphate, dodecylphenoxy tetraoxyethylene phosphate, octadecylphenoxy tetraoxyethylene phosphate, methylphenoxy pentaoxyethylene phosphate, ethylphenoxypentaoxyethylene phosphate, butylphenoxy pentaoxyethylene phosphate, hexylphenoxy pentaoxyethylene phosphate, nonylphenoxy pentaoxyethylene phosphate, dodecylphenoxy pentaoxyethylene phosphate, methylphenoxy hexaoxyethylene phosphate, ethylphenoxyhexaoxyethylene phosphate, butylphenoxy hexaoxyethylene phosphate, hexylphenoxy hexaoxyethylene phosphate, nonylphenoxy hexaoxyethylene phosphate, ethylphenoxyoctaoxyethylene phosphate, butylphenoxy octaoxyethylene phosphate, hexylphenoxy octaoxyethylene phosphate, dodecylphenoxy octaoxyethylene phosphate, etc., and sodium salts thereof are particularly preferable.

Specific examples of the alkylphenoxypolyoxypropylene phosphate include metal salts such as methylphenoxy tetrapropoxy phosphate, ethylphenoxytetrapropoxy phosphate, butylphenoxy tetrapropoxy phosphate, hexylphenoxy tetrapropoxy phosphate, nonylphenoxy tetrapropoxy phosphate, dodecylphenoxy tetrapropoxy phosphate, methylphenoxy pentapropoxy phosphate, ethylphenoxy pentapropoxy phosphate, butylphenoxy pentapropoxy phosphate, hexylphenoxy pentapropoxy phosphate, nonylphenoxy pentapropoxy phosphate, dodecylphenoxy pentapropoxy phosphate, methylphenoxy hexaoxypropoxy phosphate, ethylphenoxy hexaoxypropoxy phosphate, butylphenoxy hexaoxyprop phosphate, hexylphenoxy hexaoxyprop phosphate, nonylphenoxy hexaoxyprop phosphate, dodecylphenoxy hexaoxyprop phosphate, methylphenoxy octaoxyprop phosphate, ethylphenoxy octaoxyprop phosphate, butylphenoxy octaoxyprop phosphate, hexylphenoxy octaoxyprop phosphate, nonylphenoxy octaoxyprop phosphate, dodecylphenoxy octaoxyprop phosphate, and the like, and alkali metal salts thereof are particularly preferred, and sodium salts thereof are particularly preferred.

As the phosphate ester salt, a mono-phosphate ester salt such as a di (alkoxypolyoxyalkylene) phosphate ester sodium salt may be used alone, or a di-phosphate ester salt may be used in combination.

Examples of the sulfate salt include sodium lauryl sulfate, potassium lauryl sulfate, ammonium lauryl sulfate, sodium myristyl sulfate, sodium polyoxyethylene alkyl sulfate, sodium polyoxyethylene alkylaryl sulfate, and the like, with sodium lauryl sulfate being preferred.

Examples of the cationic emulsifier include alkyl trimethyl ammonium chloride, dialkyl ammonium chloride, benzyl ammonium chloride, and the like.

Examples of the nonionic emulsifier include: polyoxyalkylene fatty acid esters such as polyoxyethylene stearate; polyoxyalkylene alkyl ethers such as polyoxyethylene lauryl ether; polyoxyalkylene alkylphenol ethers such as polyoxyethylene nonylphenyl ether; the polyoxyethylene sorbitan alkyl ester is preferably a polyoxyalkylene alkyl ether or a polyoxyalkylene alkylphenol ether, and more preferably a polyoxyethylene alkyl ether or a polyoxyethylene alkylphenol ether.

These emulsifiers may be used singly or in combination, and the amount thereof is usually in the range of 0.01 to 10 parts by weight, preferably 0.1 to 5 parts by weight, more preferably 1 to 3 parts by weight, relative to 100 parts by weight of the monomer component.

The mixing method (mixing method) of the monomer component, water and emulsifier may be a conventional method, and examples thereof include a method of stirring the monomer, emulsifier and water using a stirrer such as a homogenizer or a disk turbine. The amount of water to be used is usually in the range of 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, and most preferably 20 to 80 parts by weight, relative to 100 parts by weight of the monomer component.

(emulsion polymerization Process)

The emulsion polymerization step in the method for producing an acrylic rubber bag of the present invention is a step of initiating polymerization in the presence of a redox catalyst comprising a radical generator and a reducing agent, and adding a chain transfer agent after the batch during the polymerization to continue the polymerization, thereby obtaining an emulsion polymerization solution.

(radical generator)

The polymerization catalyst used in the present invention is preferably a redox catalyst comprising a radical generator and a reducing agent, because it can highly improve the banbury processability and strength characteristics of the resulting acrylic rubber bag. In addition, the use of an organic radical generator as the radical generator is preferable because the injection moldability of the produced acrylic rubber bag can be further improved.

The organic radical generator is not particularly limited as long as it is an organic radical generator generally used in emulsion polymerization, and examples thereof include organic peroxides and azo compounds.

The organic peroxide is not particularly limited as long as it is a known organic peroxide used in emulsion polymerization, examples thereof include 2, 2-bis (4, 4-di- (tert-butylperoxy) cyclohexyl) propane, 1-bis- (tert-hexylperoxy) cyclohexane, 1-bis- (tert-butylperoxy) cyclohexane, n-butyl 4, 4-bis- (tert-butylperoxy) valerate, 2-bis- (tert-butylperoxy) butane, tert-butylhydroperoxide, cumene hydroperoxide, diisopropylbenzene hydroperoxide, p-terpinene hydroperoxide, benzoyl peroxide, 1, 3-tetraethylbutylhydroperoxide, tert-butylcumene peroxide, di-tert-butyl peroxide, di-tert-hexyl peroxide, di (2-tert-butylperoxyisopropyl) benzene, diisopropylbenzene peroxide diisobutyryl peroxide, bis (3, 5-trimethylhexanoyl) peroxide, dilauroyl peroxide, disuccinic acid peroxide, dibenzoyl peroxide, bis (3-methylbenzoyl) peroxide, benzoyl (3-methylbenzoyl) peroxide, diisobutyrylperoxide dicarbonate, di-n-propyl peroxydicarbonate, bis (2-ethylhexyl) peroxydicarbonate, di-sec-butyl peroxydicarbonate, 1, 3-tetramethylbutyl peroxyneodecanoate, t-hexyl peroxypivalate, t-butyl peroxypivalate, 2, 5-dimethyl-2, 5-di (2-ethylhexanoylperoxy) hexane, 1, 3-tetramethylbutylperoxy-2-ethylhexanoate, t-hexylperoxy-2-ethylhexanoate, t-butylperoxy-3, 5-trimethylhexanoate, t-hexylperoxy isopropyl monocarbonate, t-butylperoxy-2-ethylhexyl monocarbonate, 2, 5-dimethyl-2, 5-di (benzoyl peroxide) hexane, t-butylperoxyacetate, t-hexylperoxybenzoate, t-butylperoxybenzoate, 2, 5-dimethyl-2, 5-di (t-butylperoxy) hexane, and among these, diisopropylbenzene hydroperoxide, cumene hydroperoxide, p-terpene hydroperoxide, benzoyl peroxide, and the like are preferable.

As the azo compound, there is used, examples thereof include azobisisobutyronitrile, 4' -azobis (4-cyanovaleric acid), 2' -azobis [2- (2-imidazolin-2-yl) propane, 2' -azobis (propane-2-formamidine), 2' -azobis [ N- (2-carboxyethyl) -2-methylpropionamide ], 2,2' -azobis {2- [1- (2-hydroxyethyl) -2-imidazolin-2-yl ] propane }, 2' -azobis (1-imino-1-pyrrolidinyl-2-methylpropane) and 2,2' -azobis { 2-methyl-N- [1, 1-bis (hydroxymethyl) -2-hydroxyethyl ] propionamide }, and the like.

These radical generators may be used singly or in combination of two or more, and the amount thereof is usually in the range of 0.0001 to 5 parts by weight, preferably in the range of 0.0005 to 1 part by weight, more preferably in the range of 0.001 to 0.5 part by weight, relative to 100 parts by weight of the monomer component.

(reducing agent)

The reducing agent used in the present invention is not particularly limited as long as it is a reducing agent generally used in emulsion polymerization, and it is preferable to use at least two reducing agents, and it is preferable to combine a metal ion compound in a reduced state and a reducing agent other than the metal ion compound, since the banbury processability, injection moldability and strength characteristics of the obtained acrylic rubber bag can be further balanced highly.

The metal ion compound in the reduced state is not particularly limited, and examples thereof include ferrous sulfate, sodium iron hexamethylenediamine tetraacetate, cuprous naphthenate, and the like, and among these, ferrous sulfate is preferable. These metal ion compounds in the reduced state may be used singly or in combination, and the amount thereof is usually in the range of 0.000001 to 0.01 part by weight, preferably 0.00001 to 0.001 part by weight, more preferably 0.00005 to 0.0005 part by weight, relative to 100 parts by weight of the monomer component.

The reducing agent other than the metal ion compound in the reduced state used in the present invention is not particularly limited, and examples thereof include: ascorbic acid or its salts such as ascorbic acid, sodium ascorbate, potassium ascorbate, etc.; erythorbic acid or salts thereof such as erythorbic acid, sodium erythorbate, and potassium erythorbate; sulfinate salts such as sodium hydroxymethanesulfinate; sulfite of sodium sulfite, potassium sulfite, sodium bisulfite, sodium aldehyde bisulfite, potassium bisulfite; metabisulfites such as sodium metabisulfite, potassium metabisulfite, sodium metabisulfite, potassium metabisulfite and the like; thiosulfate such as sodium thiosulfate and potassium thiosulfate; phosphorous acid or salts thereof of phosphorous acid, sodium phosphite, potassium phosphite, sodium hydrogen phosphite, potassium hydrogen phosphite; pyrophosphorous acid or salts thereof such as pyrophosphorous acid, sodium pyrophosphate, potassium pyrophosphate, sodium hydrogen pyrophosphate, potassium hydrogen pyrophosphate, etc.; sodium formaldehyde sulfoxylate, and the like. 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.

These reducing agents other than the metal ion compound in the reduced state may be used singly or in combination of two or more, and the amount thereof is usually in the range of 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, relative to 100 parts by weight of the monomer component.

The preferred combination of the metal ion compound in the reduced state and the reducing agent other than the same is a combination of ferrous sulfate and ascorbic acid or a salt thereof and/or sodium formaldehyde sulfoxylate, more preferably a combination of ferrous sulfate and ascorbic acid or a salt thereof. The amount of the ferrous sulfate used in this case 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, relative to 100 parts by weight of the monomer component, and the amount of the ascorbic acid or a salt thereof and/or sodium formaldehyde sulfoxylate is usually in the range of 0.001 to 1 part by weight, preferably 0.005 to 0.5 parts by weight, more preferably 0.01 to 0.1 part by weight, relative to 100 parts by weight of the monomer component.

The amount of water used in the emulsion polymerization may be only that used in emulsification of the monomer component to be adjusted to be in the range of usually 10 to 1000 parts by weight, preferably 50 to 500 parts by weight, more preferably 80 to 400 parts by weight, most preferably 100 to 300 parts by weight, relative to 100 parts by weight of the monomer component used in the polymerization.

The emulsion polymerization may be carried out by a conventional method, and may be carried out in any of batch, semi-batch, and continuous modes. The polymerization temperature and polymerization time are not particularly limited, and may be appropriately selected depending on the kind of the polymerization initiator used, and the like. The polymerization time is usually 0.5 to 100 hours, preferably 1 to 10 hours.

The emulsion polymerization is exothermic and the polymerization reaction can be shortened if the temperature is not controlled, but in the present invention, the emulsion polymerization temperature is usually controlled to 35℃or less, preferably 0 to 35℃and more preferably 5 to 30℃and particularly preferably 10 to 25℃and, in this case, the strength characteristics of the produced acrylic rubber bag are highly balanced with the processability in kneading by a Banbury mixer or the like, and therefore, it is preferable.

(post addition of chain transfer agent)

The present invention is characterized in that it is preferable to be able to produce an acrylic rubber having a high molecular weight component and a low molecular weight component separated from each other by adding the chain transfer agent in a batch manner during the polymerization without adding the chain transfer agent at the initial stage, and the banbury processability, strength characteristics and injection moldability of the produced acrylic rubber package are highly balanced.

The chain transfer agent to be used is not particularly limited as long as it is a chain transfer agent generally used in emulsion polymerization, and, for example, a thiol compound can be preferably used.

As the thiol compound, an alkyl thiol compound having 2 to 20 carbon atoms can be generally used, and an alkyl thiol compound having 5 to 15 carbon atoms is preferable, and an alkyl thiol compound having 6 to 14 carbon atoms is more preferable.

The alkyl thiol compound may be any of an n-alkyl thiol compound, a secondary alkyl thiol compound, and a tertiary alkyl thiol compound, and is preferably an n-alkyl thiol compound or a tertiary alkyl thiol compound, and more preferably an n-alkyl thiol compound, and in this case, the effect of the chain transfer agent can be stably exhibited, and the injection moldability of the produced acrylic rubber can be improved to a high degree, and is therefore preferable.

Specific examples of the alkyl thiol compound include n-pentyl thiol, n-hexyl thiol, n-heptyl thiol, n-octyl thiol, n-decyl thiol, n-dodecyl thiol, n-tridecyl thiol, n-tetradecyl thiol, n-hexadecyl thiol, n-octadecyl thiol, sec-pentyl thiol, sec-hexyl thiol, sec-heptyl thiol, sec-octyl thiol, zhong Guiji thiol, sec-dodecyl thiol, sec-tridecyl thiol, sec-tetradecyl thiol, sec-hexadecyl thiol, sec-octadecyl thiol, tert-amyl thiol, tert-hexyl thiol, tert-heptyl thiol, tert-octyl thiol, tert-decyl thiol, tert-dodecyl thiol, tert-tridecyl thiol, tert-tetradecyl thiol, tert-hexadecyl thiol, tert-octadecyl thiol, and the like, preferably n-octyl thiol, n-dodecyl thiol, tert-dodecyl thiol, more preferably n-octyl thiol, and n-dodecyl thiol.

These chain transfer agents can be used singly or in combination of two or more kinds. The amount of the chain transfer agent used is not particularly limited, but is preferably in the range of 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 0.005 to 0.1 part by weight, most preferably 0.01 to 0.06 part by weight, based on 100 parts by weight of the monomer component, and in this case, the banbury workability, strength characteristics and injection moldability of the produced acrylic rubber bag are highly balanced.

The present invention is characterized in that the high molecular weight component and the low molecular weight component of the obtained acrylic rubber can be produced by adding the chain transfer agent in a batch manner during the polymerization without adding the chain transfer agent at the initial stage of the polymerization, and the molecular weight distribution is in a specific range, and the banbury processability, strength characteristics and injection moldability of the acrylic rubber bag can be highly balanced, and therefore, it is preferable.

The number of times of batch-wise post-addition of the chain transfer agent is not particularly limited, and may be appropriately selected depending on the purpose of use, and is usually 1 to 5 times, preferably 2 to 4 times, more preferably 2 to 3 times, and particularly preferably 2 times, and in this case, the banbury processability, strength characteristics, and injection moldability of the produced acrylic rubber bag can be highly balanced, and thus are preferable.

The timing of starting the batch-type post-addition of the chain transfer agent is not particularly limited, and may be appropriately selected depending on the purpose of use, and is generally preferably in the range of 35 to 150 minutes, most preferably 40 to 120 minutes after initiation of the polymerization, preferably in the range of 30 minutes after initiation of the polymerization, more preferably in the range of 30 to 200 minutes after initiation of the polymerization, and particularly preferably in the range of 30 to 200 minutes after initiation of the polymerization, in which case the banbury processability, strength characteristics and injection moldability of the produced acrylic rubber bag can be highly balanced.

The amount of the chain transfer agent added per one addition after the batch is not particularly limited, and may be appropriately selected depending on the purpose of use, but is usually in the range of 0.00005 to 0.5 part by weight, preferably 0.0001 to 0.1 part by weight, more preferably 0.0005 to 0.05 part by weight, particularly preferably 0.001 to 0.03 part by weight, and most preferably 0.002 to 0.02 part by weight, based on 100 parts by weight of the monomer component, and in this case, the banbury processability, strength characteristics, and injection moldability of the produced acrylic rubber bag can be highly balanced, and are therefore preferable.

After the addition of the chain transfer agent, the polymerization reaction can be continued for usually 30 minutes or more, preferably 45 minutes or more, more preferably 1 hour or more, and then ended.

(post addition of reducing agent)

In the present invention, the reducing agent of the redox catalyst can be added after the polymerization, and thus the strength characteristics and injection moldability of the produced acrylic rubber bag can be highly balanced, which is preferable.

The reducing agent added after the polymerization is the same as the above-mentioned examples and preferable ranges of the reducing agent. In the present invention, as the reducing agent to be added later, ascorbic acid or a salt thereof is preferable.

The amount of the reducing agent to be added after the polymerization is not particularly limited, and is appropriately selected depending on the purpose of use, but is usually in the range of 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 0.005 to 0.1 part by weight, and most preferably 0.01 to 0.05 part by weight, based on 100 parts by weight of the monomer component, and in this case, the productivity of the production of the acrylic rubber is excellent and the strength characteristics and injection moldability of the produced acrylic rubber bag can be highly balanced, and therefore, it is preferable.

The reducing agent added after the polymerization may be added continuously or in a batch manner, and is preferably added in a batch manner. The number of times when the reducing agent is added after the batch during the polymerization is not particularly limited, but is usually 1 to 5 times, preferably 1 to 3 times, and more preferably 1 to 2 times.

When the reducing agent added at the beginning of polymerization and during the course of polymerization is ascorbic acid or a salt thereof, the ratio of the amount of the ascorbic acid or a salt thereof added at the beginning to the amount of the ascorbic acid or a salt thereof added at the later is not particularly limited, and is usually in the range of 1/9 to 8/2, preferably in the range of 2/8 to 6/4, more preferably in the range of 3/7 to 5/5, based on the weight ratio of "the ascorbic acid or a salt thereof added at the initial"/"the ascorbic acid or a salt thereof added at the later in a batch manner", the productivity of the production of the acrylic rubber is excellent and the strength characteristics and the injection moldability of the produced acrylic rubber package can be highly balanced, and therefore, it is preferable.

The timing of the post-addition of the reducing agent is not particularly limited, and may be appropriately selected depending on the purpose of use, and is generally preferably in the range of 1 to 3 hours, more preferably 1.5 to 2.5 hours after initiation of polymerization, in which case the productivity in production of acrylic rubber is excellent and the strength characteristics and injection moldability of the produced acrylic rubber bag can be highly balanced, and thus is preferable.

The amount of the reducing agent to be added per one batch of the post-addition is not particularly limited, and may be appropriately selected depending on the purpose of use, but is usually in the range of 0.00005 to 0.5 part by weight, preferably 0.0001 to 0.1 part by weight, more preferably 0.0005 to 0.05 part by weight, and particularly preferably 0.001 to 0.03 part by weight, based on 100 parts by weight of the monomer component, and in this case, the strength characteristics and injection moldability of the produced acrylic rubber bag can be highly balanced, and thus are preferable.

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

The polymerization conversion rate of the emulsion polymerization is preferably 90% by weight or more, more preferably 95% by weight or more, and the acrylic rubber bag produced at this time is excellent in strength characteristics and free from monomer odor. At the termination of the polymerization, a polymerization terminator may be used.

(coagulation step)

The coagulation step in the method for producing an acrylic rubber bag of the present invention is a step of bringing the emulsion polymerization liquid obtained as described above into contact with a coagulant to produce an aqueous pellet.

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

The coagulant to be used is not particularly limited, and a metal salt is usually used. The metal salt may be, for example, an alkali metal, a metal salt of group 2 of the periodic table, or other metal salt, and is preferably an alkali metal salt or a metal salt of group 2 of the periodic table, more preferably a metal salt of group 2 of the periodic table, and particularly preferably a magnesium salt, and in this case, the water resistance, strength characteristics, fusion properties in injection molding, releasability, and processability of the obtained acrylic rubber bag can be highly balanced, and thus are preferable.

Examples of the alkali metal salt include: sodium salts such as sodium chloride, sodium nitrate, and sodium sulfate; potassium salts such as potassium chloride, potassium nitrate, and potassium sulfate; among these, sodium salts are preferable, and sodium chloride and sodium sulfate are particularly preferable.

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

Examples of the other metal salt 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, nickel nitrate, aluminum nitrate, tin nitrate, zinc sulfate, titanium sulfate, manganese sulfate, iron sulfate, cobalt sulfate, nickel sulfate, aluminum sulfate, and tin sulfate.

These coagulants may be used singly or in combination, and the amount thereof is usually in the range of 0.01 to 100 parts by weight, preferably 0.1 to 50 parts by weight, more preferably 1 to 30 parts by weight, relative to 100 parts by weight of the monomer component. When the coagulant is in this range, the acrylic rubber bag can be sufficiently coagulated, and the compression set resistance and water resistance at the time of crosslinking the acrylic rubber can be highly improved, so that it is preferable.

The method of contacting the emulsion polymerization liquid with the above coagulant is not particularly limited, and the method may be carried out by a conventional method, and it is preferable to add the emulsion polymerization liquid to the stirred coagulant liquid (coagulant aqueous solution) to concentrate the particle size of the aqueous aggregates of the produced acrylic rubber to 710 μm to 6.7mm, thereby significantly improving the ash removal rate during washing and dehydration and the water resistance of the obtained acrylic rubber bag.

The proportion of the produced aqueous pellet in the range of 710 μm to 6.7mm (not passing through 710 μm and passing through 6.7 mm) is not particularly limited, but is usually 30% by weight or more, preferably 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, based on the total amount of the produced aqueous pellet, and in this case, the water resistance of the acrylic rubber bag can be significantly improved, and is therefore preferred. The proportion of the produced aqueous pellet is not particularly limited in the range of 710 μm to 4.75mm (not passing through 710 μm and passing through 4.75 mm), but is usually 30% by weight or more, preferably 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, based on the total amount of the produced aqueous pellet, and in this case, the water resistance of the acrylic rubber bag can be significantly improved, and is therefore preferred. Further, the proportion of the produced aqueous pellet in the range of 710 μm to 3.35mm (not passing through 710 μm and passing through 3.35 mm) is not particularly limited, but is usually 20% by weight or more, preferably 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, based on the total amount of the produced aqueous pellet, and in this case, the water resistance of the acrylic rubber bag can be significantly improved, and thus it is preferable.

The method for producing the water-containing granules in the above-described range is not particularly limited, and for example, the method can be performed as follows: the method of contacting the emulsion polymerization liquid with the coagulant is to add the emulsion polymerization liquid to the stirred coagulant liquid (coagulant aqueous solution); or the coagulant concentration of the coagulant, the stirring number of the stirred coagulant, and the peripheral speed are specified.

The coagulant used is usually used in the form of an aqueous solution, and the concentration of the coagulant in the aqueous solution is usually in the range of 0.1 to 20% by weight, preferably 0.5 to 15% by weight, more preferably 1 to 10% by weight, and particularly preferably 1.5 to 5% by weight, and in this case, the particle size of the resulting aqueous pellets is preferably uniformly concentrated in a specific region.

The temperature of the coagulating liquid is not particularly limited, and is usually 40℃or higher, preferably 40 to 90℃and more preferably 50 to 80℃and, in this case, it is preferable to produce uniform aqueous aggregates.

As a method of bringing the emulsion polymerization liquid into contact with the coagulation liquid, a method of adding the emulsion polymerization liquid to the stirred coagulation liquid is selected, and the produced aqueous pellet is excellent in cleaning efficiency and dewatering efficiency, and can highly improve the water resistance and storage stability of the acrylic rubber bag, which is preferable.

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

Since the particle size of the aqueous pellets to be produced can be made small and uniform when the number of revolutions is a number of revolutions with which stirring is intense to some extent, it is preferable that the number of revolutions is not less than the lower limit, and generation of pellets having excessively large and excessively small particle sizes can be suppressed, and the coagulation reaction can be controlled more easily by setting the number of revolutions to not more than the upper limit.

The peripheral speed of the stirred coagulation liquid, that is, the speed of the outer periphery of the stirring blade of the stirring device is not particularly limited, and when the stirring is vigorously performed to a certain extent, the particle size of the resulting aqueous granules can be made small and uniform, and therefore, the peripheral speed is preferably usually 0.5m/s or more, preferably 1m/s or more, more preferably 1.5m/s or more, particularly preferably 2m/s or more, and most preferably 2.5m/s or more. On the other hand, the upper limit of the peripheral speed is not particularly limited, but is usually 50m/s or less, preferably 30m/s or less, more preferably 25m/s or less, and most preferably 20m/s or less, and in this case, the coagulation reaction is easily controlled, and is therefore preferable.

By setting the above-mentioned conditions of the coagulation reaction (contact method, solid content concentration of emulsion polymerization liquid, concentration and temperature of coagulation liquid, rotational speed and peripheral speed of coagulation liquid at the time of stirring, etc.) in a specific range, the shape and the pellet size of the produced aqueous pellets can be made uniform and concentrated, and the removal of the emulsifier and coagulant at the time of washing and dehydration can be significantly improved, and as a result, the water resistance and storage stability of the produced acrylic rubber bag can be highly improved, which is preferable.

(cleaning step)

The washing step in the method for producing an acrylic rubber bag of the present invention is a step of washing the aqueous pellet produced as described above.

The washing method is not particularly limited, and can be performed by, for example, mixing the produced aqueous pellets with a large amount of water.

The amount of water to be added for washing is not particularly limited, but is preferably 50 parts by weight or more, preferably 50 to 15000 parts by weight, more preferably 100 to 10000 parts by weight, and even more preferably 500 to 5000 parts by weight per 100 parts by weight of the monomer component, and in this case, the ash content in the acrylic rubber bag can be effectively reduced.

The temperature of the water to be used is not particularly limited, but it is preferably hot water, usually 40℃or higher, preferably 40 to 100℃and more preferably 50 to 90℃and particularly 60 to 80℃since the cleaning efficiency can be remarkably improved. When the temperature of the water to be used is not less than the lower limit, the emulsifier and the coagulant are released from the aqueous pellet, 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, more preferably 3 to 30 minutes.

The number of times of washing (water washing) is also not particularly limited, and is usually 1 to 10 times, preferably 1 to 5 times, more preferably 2 to 3 times. In addition, from the viewpoint of reducing the residual amount of the coagulant in the finally obtained acrylic rubber bag, the more the number of water washes is, the more the number of water washes can be reduced significantly by setting the shape of the aqueous aggregates and the aqueous aggregate size to the specific ranges and/or setting the washing temperature to the ranges described above.

(Water removal Process)

In the present invention, the aqueous pellets supplied to the screw type biaxial extrusion dryer are preferably pellets from which free water (water removal) is removed after washing.

As the dewatering machine, a known dewatering machine can be used without particular limitation, and examples thereof include a wire mesh, a screen, an electric screen, and the like, and a wire mesh and a screen are preferable.

The mesh of the dewatering machine is not particularly limited, but is usually in the range of 0.01 to 5mm, preferably 0.1 to 1mm, more preferably 0.2 to 0.6mm, and in this case, the loss of water-containing aggregates is small and water can be efficiently removed, so that it is preferable.

The water content of the dehydrated aqueous pellet, that is, the water content of the aqueous pellet to be subjected to the dehydration and drying step is not particularly limited, but is usually in the range of 50 to 80% by weight, preferably 50 to 70% by weight, more preferably 50 to 60% by weight.

The temperature of the aqueous pellet after the water removal, that is, the temperature of the aqueous pellet to be fed to the dehydration and drying step is not particularly limited, but is usually 40 ℃ or higher, preferably 40 to 100 ℃, more preferably 50 to 90 ℃, particularly preferably 55 to 85 ℃, and most preferably 60 to 80 ℃, and in this case, it is preferable to efficiently dehydrate and dry the aqueous pellet having a specific heat as high as 1.5 to 2.5KJ/kg·k and having a temperature hardly increased, as in the acrylic rubber of the present invention, using a screw type biaxial extrusion dryer.

(dehydration-drying-Forming Process)

The dehydration-drying-molding step in the method for producing an acrylic rubber bag of the present invention is a step of using a dehydration barrel having a dehydration slit, a dryer barrel under reduced pressure, and a screw type biaxial extrusion dryer having a die at the tip end, dehydrating the aqueous pellet after the above-mentioned washing and water removal as needed to a water content of 1 to 40% by weight with the dehydration barrel, drying the aqueous pellet with the dryer barrel to a water content of less than 1% by weight, and extruding a sheet-like dried rubber from the die.

(dehydration of aqueous pellets in the barrel section of the dehydrator)

The dewatering of the aqueous pellets is carried out in a dewatering barrel having a screw type twin screw extrusion dryer with dewatering slots. The mesh size of the dewatering slit may be appropriately selected depending on the conditions of use, and is usually in the range of 0.01 to 5mm, preferably 0.1 to 1mm, more preferably 0.2 to 0.6mm, and in this case, the loss of the aqueous pellets is small and the dewatering of the aqueous pellets can be efficiently performed, which is preferable.

The number of the dehydration cylinders in the screw type biaxial extrusion dryer is not particularly limited, but is usually plural, preferably 2 to 10, more preferably 3 to 6, and in this case, dehydration of the adhesive acrylic rubber can be efficiently performed, which is preferable.

In the dewatering cylinder, there are two modes of removing water in a liquid state (drainage) from the dewatering slit and removing water in a vapor state (drainage), and in the present invention, drainage is defined as dewatering and drainage is defined as predrying.

In the dehydration of the hydrous pellets, the water discharged from the dehydration slit may be in any state of a liquid state (drain) or a vapor state (drain), and in the case of using a screw type biaxial extrusion dryer having a plurality of dehydration barrels, it is preferable to efficiently dehydrate the adhesive acrylic rubber by combining drain and drain. Whether the screw type biaxial extrusion dryer having three or more dehydration barrels is a dehydration barrel of a drainage type or a dehydration barrel of a steam discharge type can be appropriately performed according to the purpose of use, and generally, the drainage type barrels are increased in the case of reducing the ash content in the produced acrylic rubber, and the steam discharge type barrels are increased in the case of reducing the water content.

The setting temperature of the dehydration barrel may be appropriately selected depending on the monomer composition, ash amount, water content, operating conditions and the like of the acrylic rubber, and is usually in the range of 60 to 150 ℃, preferably 70 to 140 ℃, more preferably 80 to 130 ℃. The setting temperature of the dehydration barrel for dehydration in a drained state is usually 60 to 120 ℃, preferably 70 to 110 ℃, more preferably 80 to 100 ℃. The set temperature of the dehydration barrel for dehydration in the vapor-exhausted state is usually in the range of 100 to 150 ℃, preferably 105 to 140 ℃, and more preferably 110 to 130 ℃.

The water content after dewatering by draining water extruded from the hydrous pellets is not particularly limited, but is usually 1 to 40% by weight, preferably 5 to 35% by weight, more preferably 10 to 35% by weight, and in this case, productivity and ash removal efficiency are highly balanced, and thus preferable.

When dehydration of the acrylic rubber having adhesiveness of the reactive group is performed using a centrifuge or the like, the acrylic rubber adheres to the dehydration slit portion and is hardly dehydrated (the water content is about 45 to 55% by weight), and in the present invention, the water content can be reduced to the above range by using a screw type biaxial extrusion dryer having a dehydration slit and forcibly extruded with a screw.

For dehydration of the aqueous pellets in the case of having a water-draining type dehydrator cylinder and a steam-draining type dehydrator cylinder, the water content after water draining in the water-draining type dehydrator cylinder is usually 5 to 40% by weight, preferably 10 to 40% by weight, more preferably 15 to 35% by weight, and the water content after pre-drying in the steam-draining type dehydrator cylinder is usually 1 to 30% by weight, preferably 3 to 20% by weight, more preferably 5 to 15% by weight.

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

(drying of aqueous pellets in the dryer section)

The above-described drying of the dehydrated aqueous pellets is performed by a screw type biaxial extrusion dryer having a dryer barrel portion at a reduced pressure. Drying under reduced pressure is preferable because the drying production efficiency is improved, and air existing in the acrylic rubber can be removed, so that an acrylic rubber bag having a high specific gravity and excellent storage stability can be produced. In the present invention, the acrylic rubber is melted under reduced pressure and dried by extrusion, whereby the storage stability of the acrylic rubber bag can be highly improved. The storage stability of the acrylic rubber bag is closely related to the specific gravity of the acrylic rubber bag, and can be controlled, and in the case of controlling the storage stability to be high and high with a large specific gravity, the degree of vacuum of extrusion drying can be controlled.

The vacuum degree of the dryer cylinder is preferably 1 to 50kPa, more preferably 2 to 30kPa, and even more preferably 3 to 20kPa, since the aqueous pellets can be efficiently dried and the air in the acrylic rubber bag can be removed, and the storage stability of the acrylic rubber can be significantly improved.

The setting temperature of the dryer cylinder is preferably selected as appropriate, and is usually in the range of 100 to 250 ℃, preferably 110 to 200 ℃, more preferably 120 to 180 ℃, in which case the acrylic rubber is free from scorching and deterioration, can be dried efficiently, and can reduce the gel amount of methyl ethyl ketone insoluble components in the acrylic rubber bag.

The number of the dryer cylinders in the screw type biaxial extrusion dryer is not particularly limited, but is usually plural, preferably 2 to 10, more preferably 3 to 8. The vacuum level in the case of having a plurality of dryer cylinders may be changed so that the vacuum level of all the dryer cylinders is similar. The set temperature in the case of having a plurality of dryer cylinders may be set so that the temperature of all the dryer cylinders is approximately the same, or may be changed, and it is preferable to improve the drying efficiency when the temperature of the discharge portion (the side close to the die) is higher than the temperature of the introduction portion (the side close to the dryer cylinder).

The moisture content of the dried rubber after drying is usually less than 1% by weight, preferably 0.8% by weight or less, more preferably 0.6% by weight or less. In the present invention, it is preferable to melt-extrude the dried rubber in a screw type biaxial extrusion dryer so that the water content of the dried rubber is at this value (the state where water is substantially removed), because the gel content of methyl ethyl ketone insoluble components of the sheet-like or bag-like acrylic rubber can be reduced. In the present invention, the strength characteristics of the acrylic rubber bag melt-kneaded or melt-kneaded and dried by a screw type biaxial extruder and the Banbury processability are highly balanced, and therefore, they are preferable. In the present invention, "melt kneading" or "melt kneading and drying" means that the acrylic rubber is kneaded (mixed) in a molten state or extruded in a molten state in a screw type biaxial extrusion dryer, and is dried at this stage, or the acrylic rubber is kneaded in a molten (plasticizable) state by a screw type biaxial extrusion dryer and is extruded and dried.

In the present invention, the shear rate of the acrylic rubber in a substantially water-free state in the dryer barrel of the screw type biaxial extrusion dryer is not particularly limited, but is usually 5[1/s ] or more, preferably 10 to 400[1/s ], more preferably 20 to 250[1/s ], and in this case, the storage stability, injection moldability, banbury processability, strength characteristics and compression set resistance of the obtained acrylic rubber bag are highly balanced, and therefore preferable.

The shear viscosity of the acrylic rubber in the screw type biaxial extrusion dryer used in the present invention, particularly in the dryer barrel, is not particularly limited, but is usually not more than 12000[ Pa.s ], preferably 1000 to 12000[ Pa.s ], more preferably 2000 to 10000[ Pa.s ], particularly preferably 3000 to 7000[ Pa.s ], and most preferably 4000 to 6000[ Pa.s ], and in this case, the storage stability, injection moldability, banbury processability and strength characteristics of the obtained acrylic rubber package are highly balanced, and therefore, are preferable.

(extrusion of dried rubber from die head)

The dried rubber dehydrated and dried in the screw sections of the dehydrator cylinder and the dryer cylinder is fed to a non-screw rectifying die section, and extruded from the die section into a desired shape. The perforated plate and the metal mesh may or may not be provided between the screw portion and the die portion.

The extruded dry rubber is preferably obtained by extruding a die in a substantially rectangular shape and in a sheet form, because it is less likely to take in air and has a high specific gravity and excellent storage stability.

The resin pressure of the die head is not particularly limited, but is usually in the range of 0.1 to 10MPa, preferably 0.5 to 5MPa, more preferably 1 to 3MPa, and in this case, the air inclusion of the acrylic rubber bag is small (high specific gravity) and the productivity is excellent, so that it is preferable.

(screw type biaxial extrusion dryer and operating conditions)

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

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

The ratio (L/D) of the screw length (L) to the screw diameter (D) of the screw type biaxial extrusion dryer to be used is not particularly limited, but is usually in the range of 10 to 100, preferably 20 to 80, more preferably 30 to 60, and in this case, the water content can be made to be less than 1% by weight without causing a decrease in the molecular weight of the dried rubber or scorch.

The rotation speed (N) of the screw type biaxial extrusion dryer to be used may be appropriately selected depending on the respective conditions, and is usually 10 to 1000rpm, preferably 50 to 750rpm, more preferably 100 to 500rpm, and most preferably 120 to 300rpm, and in this case, the water content of the acrylic rubber bag and the gel content of the methyl ethyl ketone insoluble component can be efficiently reduced, which is preferable.

The extrusion amount (Q) of the screw type biaxial extrusion dryer to be used is not particularly limited, but is usually in the range of 100 to 1500 kg/hr, preferably 300 to 1200 kg/hr, more preferably 400 to 1000 kg/hr, and most preferably 500 to 800 kg/hr.

The ratio (Q/N) of the extrusion amount (Q) to the rotation speed (N) of the screw type biaxial extrusion dryer to be used is not particularly limited, but is usually in the range of 2 to 10, preferably 3 to 8, more preferably 4 to 6.

The maximum torque of the screw type biaxial extrusion dryer to be used is not particularly limited, but is usually in the range of 5 to 125 N.m, preferably 10 to 100 N.m, more preferably 10 to 50 N.m, particularly preferably 15 to 45 N.m, and in this case, the injection moldability, banbury processability and strength characteristics of the produced acrylic rubber bag can be highly balanced, and therefore, it is preferable.

The specific energy consumption of the screw type biaxial extrusion dryer to be used is not particularly limited, but is usually in the range of 0.01 to 0.3[ kw.h/kg ] or more, preferably 0.05 to 0.2[ kw.h/kg ], more preferably 0.1 to 0.2[ kw.h/kg ], and in this case, the injection moldability, banbury processability and strength characteristics of the obtained acrylic rubber bag are highly balanced, and therefore, it is preferable.

The specific power of the screw type biaxial extrusion dryer to be used is not particularly limited, but is usually in the range of 0.1 to 0.6[ A.multidot.h/kg ], preferably 0.15 to 0.55[ A.multidot.h/kg ], more preferably 0.2 to 0.5[ A.multidot.h/kg ], and in this case, the injection moldability, banbury processability and strength characteristics of the obtained acrylic rubber bag are highly balanced, and therefore, it is preferable.

The shear rate of the screw type biaxial extrusion dryer used is not particularly limited, but is usually 5 to 150[1/s ] or more, preferably 10 to 100[1/s ], and more preferably 25 to 75[1/s ], and in this case, the storage stability, injection moldability, banbury processability and strength characteristics of the obtained acrylic rubber bag are highly balanced, and thus preferable.

The shear viscosity of the acrylic rubber in the screw type biaxial extrusion dryer to be used is not particularly limited, but is usually 4000 to 8000[ Pa.s ] or less, preferably 4500 to 7500[ Pa.s ], and more preferably 5000 to 7000[ Pa.s ], and in this case, the storage stability, injection moldability, banbury processability and strength characteristics of the obtained acrylic rubber bag are highly balanced, and therefore preferable.

In this way, in the present invention, it is preferable to use an extrusion dryer having a twin screw, because dehydration, drying, and molding can be performed under high shear conditions.

(sheet-like Dry rubber)

The shape of the dried rubber extruded from the screw type biaxial extrusion dryer is preferably a sheet shape, and in this case, the specific gravity can be increased without involving air, and the storage stability is highly improved. The sheet-like dry rubber extruded from the screw type biaxial extrusion dryer is generally cooled, cut and made into sheet-like acrylic rubber for use.

The thickness of the sheet-like dry rubber extruded from the screw type biaxial extrusion dryer is not particularly limited, but is usually in the range of 1 to 40mm, preferably 2 to 35mm, more preferably 3 to 30mm, most preferably 5 to 25mm, and in this case, the handling property and productivity are excellent, and therefore, it is preferable. In particular, since the thermal conductivity of the sheet-like dry rubber is as low as 0.15 to 0.35W/mK, the thickness of the sheet-like dry rubber is usually in the range of 1 to 30mm, preferably 2 to 25mm, more preferably 3 to 15mm, particularly preferably 4 to 12mm in the case of remarkably improving the productivity by improving the cooling efficiency.

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

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

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

The sheet-like dry rubber extruded from the screw type biaxial extrusion dryer is not particularly limited, but is usually in the range of 1500 to 6000[ Pa.s ], preferably 2000 to 5000[ Pa.s ], more preferably 2500 to 4500[ Pa.s ], and most preferably 3000 to 4000[ Pa.s ] at a complex viscosity ([ eta ]100 ℃) at 100℃and, in this case, the extrudability and shape retention as a sheet are highly balanced, and therefore, it is preferable. That is, the extrusion properties can be further improved by setting the complex viscosity to the lower limit or more, and deformation and fracture of the shape of the sheet-like dry rubber can be suppressed by setting the complex viscosity to the upper limit or less.

(Cooling step to cutting step)

The sheet-like dry rubber extruded from the screw type biaxial extrusion dryer can be folded directly and used, and can be cut off normally.

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

The cutting temperature of the sheet-like dry rubber is not particularly limited, but is usually 60℃or lower, preferably 55℃or lower, more preferably 50℃or lower, and in this case, the cutting property and productivity are highly balanced, and therefore, it is preferable.

The sheet-like dry rubber is not particularly limited, and is preferably cut continuously without involving air at a complex viscosity ([ eta ]60 ℃) of 60℃of usually not more than 15000[ Pa.s ], preferably 2000 to 10000[ Pa.s ], more preferably 2500 to 7000[ Pa.s ], and most preferably 2700 to 5500[ Pa.s ].

The ratio of the complex viscosity at 100 ℃ ([ eta ]100 ℃) to the complex viscosity at 60 ℃ ([ eta ]60 ℃) ([ eta ]100 ℃/[ eta ]60 ℃) of the sheet-like dry rubber is not particularly limited and can be appropriately selected depending on the purpose of use, and is usually at least 0.5, preferably at least 0.6, more preferably at least 0.7, and the ratio of the complex viscosity at 100 ℃ ([ eta ]100 ℃) to the complex viscosity at 60 ℃ ([ eta ]60 ℃) ([ eta ]100 ℃/[ eta ]60 ℃) of the sheet-like dry rubber is also usually at 0.5 to 0.99, preferably at 0.55 to 0.95, more preferably at 0.6 to 0.9, particularly preferably at 0.65 to 0.85, most preferably at 0.7 to 0.8, and at this time, the air entanglement is small and the cutting and productivity are highly balanced, and therefore preferable.

The method for cooling the sheet-like dry rubber is not particularly limited, and the sheet-like dry rubber may be left at room temperature, and since the thermal conductivity of the sheet-like dry rubber is 0.15 to 0.35W/mK and very small, forced cooling by air blowing or an air cooling system under cool air, a water spraying system, a dipping system in water, or the like is preferable, and an air cooling system by air blowing or under cool air is particularly preferable in order to improve productivity.

In the air cooling system of the sheet-like dry rubber, for example, the sheet-like dry rubber can be extruded from a screw extruder onto a conveyor such as a conveyor belt, and 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 ℃, preferably 5 to 25 ℃, more preferably 10 to 20 ℃. The length of cooling is not particularly limited, but is usually 40℃per hour or more, preferably 50℃per hour or more, more preferably 100℃per hour or more, and particularly preferably 150℃per hour or more, and in this case, the sheet-like dry rubber is preferably easily cut. In the present invention, the cooling rate of the sheet-like dry rubber is usually 40℃per hour or more, preferably 50℃per hour or more, more preferably 100℃per hour or more, and particularly preferably 150℃per hour or more, and in this case, the scorch stability when the acrylic rubber is coated into a rubber composition is excellent, and therefore, it is preferable.

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

(lamination step)

The lamination step in the method for producing an acrylic rubber bag according to the present invention is a step of laminating the sheet-like dry rubber to obtain an acrylic rubber bag excellent in storage stability with less air inclusion.

The lamination temperature of the sheet-like dry rubber is not particularly limited, but is usually 30℃or higher, preferably 35℃or higher, more preferably 40℃or higher, and in this case, air involved in lamination can escape, which is preferable. The number of laminated sheets is appropriately selected according to the size or weight of the acrylic rubber bag. The acrylic rubber bag of the present invention is integrated by the self weight of the laminated sheet-like dry rubber.

The acrylic rubber bag of the present invention thus obtained is excellent in handling properties, and also excellent in banbury workability, crosslinkability, strength characteristics, compression set resistance, water resistance, storage stability, and injection moldability, as compared with the pellet-like acrylic rubber, and can be used as it is or cut into a desired amount and put into a mixer such as a banbury mixer or a roll.

< rubber composition >

The rubber composition of the present invention is characterized by comprising a rubber component containing the acrylic rubber bag, a filler and a crosslinking agent.

The acrylic rubber bag of the present invention may be used alone as the rubber component which is the main component of the rubber composition of the present invention, or may be used in combination with other rubber components as required. The content of the acrylic rubber composition of the present invention in the rubber component may be appropriately selected depending on 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 bag 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, fluororubber, olefin-based elastomer, styrene-based elastomer, vinyl chloride-based elastomer, polyester-based elastomer, polyamide-based elastomer, polyurethane-based elastomer, polysiloxane-based elastomer, and the like.

These other rubber components can be used singly or in combination of two or more. The shape of the other rubber component may be any of a pellet, a strand, a bale, a sheet, a powder, and the like. The content of the other rubber component in the whole rubber component may be appropriately selected within a range that does not impair the effect of the present invention, and is, for example, generally 70% by weight or less, preferably 50% by weight or less, more preferably 30% by weight or less.

The filler contained in the rubber composition is not particularly limited, and examples thereof include reinforcing fillers and non-reinforcing fillers, and reinforcing fillers are preferable, and in this case, the rubber composition is excellent in banbury processability, injection moldability and short-time crosslinkability, and the crosslinked product is highly excellent in water resistance, strength characteristics and compression set resistance, and therefore is preferable.

Examples of the reinforcing filler include: carbon blacks such as furnace black, acetylene black, thermal black, channel black, and graphite; and silica such as wet silica, dry silica and colloidal silica. Examples of the non-reinforcing filler include quartz powder, diatomaceous earth, zinc oxide, basic magnesium carbonate, activated calcium carbonate, magnesium silicate, aluminum silicate, titanium dioxide, talc, aluminum sulfate, calcium sulfate, and barium sulfate.

These fillers may be used alone or in combination, and the amount thereof may be appropriately selected within a range not to impair the effects of the present invention, and is usually in a range of 1 to 200 parts by weight, preferably in a range of 10 to 150 parts by weight, more preferably in a range of 20 to 100 parts by weight, relative to 100 parts by weight of the rubber component.

The crosslinking agent used in the rubber composition is not particularly limited, and conventionally known crosslinking agents may be selected according to the purpose of use, and examples thereof include inorganic crosslinking agents such as sulfur compounds, organic crosslinking agents, and the like, and organic crosslinking agents are preferable. The crosslinking agent may be any of a polyvalent compound and a monobasic compound, and preferably the reactive group is two or more polyvalent compounds. Further, the crosslinking agent may be either an ion-crosslinkable compound or a radical-crosslinkable compound, and is preferably an ion-crosslinkable compound.

The organic crosslinking agent is not particularly limited, but is preferably an ion-crosslinkable organic compound, and particularly preferably a polyion organic compound. When the crosslinking agent is a polyion organic compound (polyion crosslinkable compound), the rubber composition is particularly preferable because it is excellent in banbury workability, injection moldability and crosslinking property in a short period of time, and the crosslinked product is highly excellent in water resistance, strength characteristics and compression set resistance. The "ion" of the ion-crosslinkable or multi-element ion is an ion reactive ion, and is not particularly limited as long as it is an ion that reacts with an ion reactive group of the monomer containing a reactive group as an ion of the above-mentioned acrylic rubber, and examples thereof include ion-crosslinkable organic compounds having an ion reactive group such as an amine group, an epoxy group, a carboxyl group, and a thiol group.

Specific examples of the polyionic organic compound include a polyamine compound, a polyepoxide compound, a polycarboxylic acid compound, a polythiol compound, and the like, and a polyamine compound and a polythiol compound are preferable, and a polyamine compound is more preferable.

Examples of the polyamine compound include: aliphatic polyamine compounds such as hexamethylenediamine, hexamethylenediamine carbamate, N' -biscinnamaldehyde-1, 6-hexamethylenediamine; 4,4 '-methylenedianiline, p-phenylenediamine, m-phenylenediamine, 4' -diaminodiphenyl ether, 3,4 '-diaminodiphenyl ether, 4' - (m-phenylenediisopropylene) diphenylamine, 4'- (p-phenylenediisopropylene) diphenylamine aromatic polyamine compounds such as 2,2' -bis [4- (4-aminophenoxy) phenyl ] propane, 4 '-diaminobenzanilide, 4' -bis (4-aminophenoxy) biphenyl, m-xylylenediamine, p-xylylenediamine, and 1,3, 5-benzenetriamine. Among these, hexamethylenediamine carbamate, 2' -bis [4- (4-aminophenoxy) phenyl ] propane and the like are preferable. As the polyamine compound, carbonates of these can also be preferably used. These polyamine compounds are particularly preferably used in combination with a carboxyl group-containing acrylic rubber bag or an epoxy group-containing acrylic rubber bag.

As the polythiol compounds, preferably using triazine thiol compounds, can be cited for example, 6-three mercapto-s three triazine, 2-two amino-4, 6-two thiol-s three triazine, 1-two butyl amino 3, 5-two mercapto three triazine, 2-two butyl amino 4, 6-two thiol-s three triazine, 1-phenyl amino 3, 5-two mercapto three triazine, 2,4, 6-three mercapto-1, 3,5 three triazine, 1-hexyl amino 3, 5-two mercapto three triazine. These triazine thiol compounds are particularly preferably used in combination with an acrylic rubber bag containing chlorine atoms.

Examples of the other polyvalent organic compound include a polyvalent carboxylic acid compound such as tetradecanedioic acid, a metal dithiocarbamate such as zinc dimethyldithiocarbamate, and the like. These other polyvalent organic compounds are particularly preferably used in combination with an epoxy group-containing acrylic rubber bag.

These crosslinking agents may be used singly or in combination, and the amount thereof is usually 0.001 to 20 parts by weight, preferably 0.1 to 10 parts by weight, more preferably 0.1 to 5 parts by weight, relative to 100 parts by weight of the rubber component. When the amount of the crosslinking agent is within this range, the rubber elasticity can be sufficiently improved, and the mechanical strength as a crosslinked rubber product can be improved.

The rubber composition of the present invention may contain an antioxidant as needed. The type of the antioxidant is not particularly limited, and examples thereof include: other phenol-based antioxidants such as 2, 6-di-tert-butyl-4-methylphenol, 2, 6-di-tert-butylphenol, butylhydroxyanisole, 2, 6-di-tert-butyl- α -dimethylamino-p-cresol, octadecyl-3- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate, styrenated phenol, 2' -methylene-bis (6- α -methyl-benzyl-p-cresol), 4' -methylenebis (2, 6-di-tert-butylphenol), 2' -methylene-bis (4-methyl-6-tert-butylphenol), 2, 4-bis [ (octylthio) methyl ] -6-methylphenol, 2' -thiobis- (4-methyl-6-tert-butylphenol), 4' -thiobis- (6-tert-butyl-o-cresol), 2, 6-di-tert-butyl-4- (4, 6-bis (octylthio) -1,3, 5-triazin-2-ylamino) phenol; phosphite antioxidants such as tris (nonylphenyl) phosphite, diphenylisodecyl phosphite, tetraphenyl dipropylene glycol and bisphosphite; thioester-based antioxidants such as dilauryl thiodipropionate; amine-based antioxidants such as phenyl- α -naphthylamine, phenyl- β -naphthylamine, p- (p-toluenesulfonamide) -diphenylamine, 4'- (α, α -dimethylbenzyl) diphenylamine, N-diphenyl-p-phenylenediamine, N-isopropyl-N' -phenyl-p-phenylenediamine, butyraldehyde-aniline polycondensate; imidazole-based antioxidants such as 2-mercaptobenzimidazole; quinoline antioxidants such as 6-ethoxy-2, 4-trimethyl-1, 2-dihydroquinoline; hydroquinone-based antioxidants such as 2, 5-di- (t-amyl) hydroquinone. Among these, amine-based antioxidants are particularly preferable.

These antioxidants may be used singly or in combination, and the amount thereof is in the range of 0.01 to 15 parts by weight, preferably 0.1 to 10 parts by weight, more preferably 1 to 5 parts by weight, relative to 100 parts by weight of the rubber component.

The rubber composition of the present invention contains the rubber component of the acrylic rubber bag of the present invention, a filler and a crosslinking agent as essential components, and further contains an anti-aging agent as needed, and further optionally contains other additives commonly used in the art such as a crosslinking aid, a crosslinking accelerator, a crosslinking retarder, a silane coupling agent, a plasticizer, a processing aid, a lubricant, a pigment, a colorant, an antistatic agent, a foaming agent, and the like as needed. These other compounding agents may be used singly or in combination of two or more kinds, and the compounding amount thereof may be appropriately selected within a range not impairing the effects of the present invention.

The method for producing the rubber composition of the present invention includes a method of mixing the rubber component containing the acrylic rubber bag of the present invention, the filler, the crosslinking agent, and optionally the antioxidant and other compounding agents, and any method conventionally used in the rubber processing field can be used at the time of mixing, and for example, an open roll, a Banbury mixer, various kneaders, and the like can be used. The mixing order of the components may be in accordance with a usual order in the rubber processing field, and it is preferable that, for example, components which are not easily reacted or decomposed by heat are sufficiently mixed and then a crosslinking agent or the like which is a component which is easily reacted or decomposed by heat is mixed at a temperature at which no reaction or decomposition occurs in a short period of time.

< rubber Cross-Linked substance >)

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

The rubber crosslinked product of the present invention can be produced by the following method: the rubber composition of the present invention is molded by a molding machine, such as an extruder, an injection molding machine, a compressor, or a roll, which corresponds to a desired shape, and is subjected to a crosslinking reaction by heating, whereby the shape is fixed to obtain a rubber crosslinked product. In this case, the crosslinking may be performed after the preliminary molding, or may be performed simultaneously with the molding. The molding temperature is usually 10 to 200℃and preferably 25 to 150 ℃. The crosslinking temperature is usually 100 to 250 ℃, preferably 130 to 220 ℃, more preferably 150 to 200 ℃, and the crosslinking time is usually 0.1 minutes to 10 hours, preferably 1 minute to 5 hours. As the heating method, a method used for crosslinking the rubber such as pressing heating, steam heating, oven heating, and hot air heating may be appropriately selected.

The rubber crosslinked product of the present invention may be further heated to perform secondary crosslinking depending on the shape, size, etc. of the rubber crosslinked product. The secondary crosslinking varies depending on the heating method, crosslinking temperature, shape, etc., and is preferably carried out for 1 to 48 hours. The heating method and the heating temperature are properly selected.

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

The rubber crosslinked material of the present invention can be preferably used as, for example, by effectively utilizing the above characteristics: sealing materials such as O-rings, sealing materials, diaphragms, oil seals, shaft seals, bearing seals, mechanical seals, wellhead seals, seals for electrical/electronic devices, and seals for air compression devices; a rocker cover gasket attached to a connecting portion of the cylinder block and the cylinder head, an oil pan gasket attached to a connecting portion of the oil pan and the cylinder head or the transmission case, a gasket for a fuel cell spacer attached between a pair of cases sandwiching a unit cell having a positive electrode, an electrolyte plate and a negative electrode, a gasket for a hard disk drive top cover, and the like; a buffer material and a vibration-proof material; a wire coating material; industrial belts; tubes/hoses; sheets, and the like.

The rubber crosslinked product of the present invention is preferably used as an extrusion molded product and a die crosslinked product used for automobiles, for example, in fuel oil hoses such as fuel hoses, filler neck hoses, exhaust hoses, paper hoses, and fuel tanks such as oil hoses; a turbo charge air hose; an air hose such as an emission control hose; various hoses such as radiator hoses, heater hoses, brake hoses, air conditioning hoses, and the like.

Device structure for manufacturing acrylic rubber bag

Next, an apparatus structure for manufacturing an acrylic rubber bag according to an embodiment of the present invention will be described. Fig. 1 is a diagram schematically showing an example of an acrylic rubber manufacturing system having an apparatus structure for manufacturing an acrylic rubber bag according to an embodiment of the present invention. In the production of the acrylic rubber bag of the present invention, for example, an acrylic rubber production system 1 shown in fig. 1 can be used.

The acrylic rubber production system 1 shown in fig. 1 is composed of an emulsion polymerization reactor, a coagulation device 3, a cleaning device 4, a water remover 43, and a screw type biaxial extrusion dryer, which are not shown.

The emulsion polymerization reactor is configured to perform the above-described treatment in the emulsion polymerization step. Although not shown in fig. 1, the emulsion polymerization reactor includes, for example, a polymerization reaction tank, a temperature control unit for controlling a reaction temperature, and a stirring device having a motor and stirring blades. In the emulsion polymerization reactor, water and an emulsifier are mixed with a monomer component for forming an acrylic rubber, and the mixture is emulsified while being properly stirred by a stirrer, and an emulsion polymerization reaction is initiated in the presence of a redox catalyst comprising an organic radical generator and a reducing agent, and a chain transfer agent is added after the polymerization is batchwise, whereby an emulsion polymerization solution can be obtained. The emulsion polymerization reactor may be any of a batch type, a semi-batch type and a continuous type, and may be any of a tank type reactor and a tube type reactor.

The coagulation apparatus 3 shown in fig. 1 is configured to perform the above-described coagulation step. As schematically illustrated in fig. 1, the solidification apparatus 3 includes, for example, a stirring tank 30, a heating unit 31 for heating the inside of the stirring tank 30, a temperature control unit not illustrated for controlling the temperature in the stirring tank 30, a stirring device 34 including a motor 32 and stirring blades 33, and a drive control unit not illustrated for controlling the rotation number and rotation speed of the stirring blades 33. In the coagulation apparatus 3, the emulsion polymerization liquid obtained in the emulsion polymerization reactor is brought into contact with a coagulation liquid to coagulate the emulsion polymerization liquid, whereby an aqueous pellet can be produced.

In the coagulation device 3, for example, a method of adding the emulsion polymerization liquid to the stirred coagulation liquid can be used as a method of contacting the emulsion polymerization liquid with the coagulation liquid. That is, the agitation tank 30 of the coagulation apparatus 3 is filled with a coagulation liquid in advance, and an emulsion polymerization liquid is added to the coagulation liquid and brought into contact with the coagulation liquid to coagulate the emulsion polymerization liquid, thereby producing an aqueous pellet.

The heating unit 31 of the solidifying apparatus 3 is configured to heat the solidifying liquid filled in the stirring tank 30. The temperature control unit of the solidifying apparatus 3 is configured to control the temperature in the stirring tank 30 by controlling the heating operation of the heating unit 31 while monitoring the temperature in the stirring tank 30 measured by the thermometer. The temperature of the solidification liquid in the stirring tank 30 is usually controlled to a range of 40 ℃ or higher, preferably 40 to 90 ℃, and more preferably 50 to 80 ℃ by the temperature control unit.

The stirring device 34 of the solidifying apparatus 3 is configured to stir the solidifying liquid filled in the stirring tank 30. Specifically, the stirring device 34 has a motor 32 that generates rotational power and a stirring blade 33 that extends in a direction perpendicular to the rotation axis of the motor 32. The stirring blade 33 can rotate about a rotation axis by the rotation power of the motor 32 in the coagulation liquid filled in the stirring tank 30, thereby allowing the coagulation liquid to flow. The shape, size, number of the stirring vanes 33, and the like are not particularly limited.

The drive control unit of the coagulation device 3 is configured to control the rotational drive of the motor 32 of the stirring device 34, and set the rotation number and rotation speed of the stirring blade 33 of the stirring device 34 to predetermined values. The stirring amount of the coagulation liquid is controlled by the drive control unit to be, for example, usually 100rpm or more, preferably 200 to 1000rpm, more preferably 300 to 900rpm, and particularly preferably 400 to 800rpm by controlling the rotation of the stirring blade 33. The rotation of the stirring blade 33 is controlled by the drive control unit so that the peripheral speed of the solidification liquid is usually 0.5m/s or more, preferably 1m/s or more, more preferably 1.5m/s or more, particularly preferably 2m/s or more, and most preferably 2.5m/s or more. Further, the rotation of the stirring blade 33 is controlled by the drive control unit so that the upper limit value of the peripheral speed of the solidification liquid is usually 50m/s or less, preferably 30m/s or less, more preferably 25m/s or less, and most preferably 20m/s or less.

The cleaning apparatus 4 shown in fig. 1 is configured to perform the above-described cleaning process.

As schematically illustrated in fig. 1, the cleaning apparatus 4 includes, for example, a cleaning tank 40, a heating unit 41 for heating the interior of the cleaning tank 40, and a temperature control unit, not illustrated, for controlling the temperature in the cleaning tank 40. In the cleaning device 4, the amount of ash in the finally obtained acrylic rubber bag can be effectively reduced by mixing and cleaning the aqueous pellets produced in the coagulation device 3 with a large amount of water.

The heating unit 41 of the cleaning apparatus 4 is configured to heat the inside of the cleaning tank 40. The temperature control unit of the cleaning apparatus 4 is configured to control the temperature in the cleaning tank 40 by controlling the heating operation of the heating unit 41 while monitoring the temperature in the cleaning tank 40 measured by the thermometer. As described above, the temperature of the washing water in the washing tub 40 is generally controlled to 40 ℃ or higher, preferably 40 to 100 ℃, more preferably 50 to 90 ℃, and most preferably 60 to 80 ℃.

The aqueous pellets washed by the washing apparatus 4 are supplied to a screw type biaxial extrusion dryer 5 for performing a dehydration step and a drying step. At this time, the washed aqueous pellets are preferably supplied to the screw type biaxial extrusion dryer 5 through a water remover 43 capable of separating free water. The water remover 43 can use, for example, a metal mesh, a screen, an electric screen, or the like.

When the washed aqueous pellets are supplied to the screw type biaxial extrusion dryer 5, the aqueous pellets have a temperature of 40 ℃ or higher, more preferably 60 ℃ or higher. For example, by setting the temperature of the water used for washing in the washing device 4 to 60 ℃ or higher (for example, 70 ℃), the temperature of the aqueous pellets when supplied to the screw type biaxial extrusion dryer 5 can be maintained at 60 ℃ or higher, or the temperature of the aqueous pellets can be heated to 40 ℃ or higher, preferably 60 ℃ or higher when transported from the washing device 4 to the screw type biaxial extrusion dryer 5. This can effectively perform the dehydration step and the drying step as subsequent steps, and can greatly reduce the water content of the finally obtained dried rubber.

The screw type biaxial extrusion dryer 5 shown in fig. 1 is configured to perform the above-described dehydration step and drying step. In fig. 1, a screw type biaxial extrusion dryer 5 is shown as a preferred example, but a centrifugal separator, a squeezer, or the like may be used as a dehydrator for performing the dehydration step, and a hot air dryer, a reduced pressure dryer, an expansion dryer, a kneading dryer, or the like may be used as a dryer for performing the drying step.

The screw type biaxial extrusion dryer 5 is configured to mold the dried rubber obtained through the dehydration step and the drying step into a predetermined shape and discharge the molded rubber. Specifically, the screw type biaxial extrusion dryer 5 is configured to have a dehydrator cylinder 53 having a function as a dehydrator for dehydrating the aqueous pellets washed by the washing device 4; a dryer barrel section 54 having a function as a dryer for drying the aqueous pellets; also provided is a die 59 having a molding function for molding the aqueous pellets on the downstream side of the screw type biaxial extrusion dryer 5.

The structure of the screw type biaxial extrusion dryer 5 will be described below with reference to fig. 2.

Fig. 2 shows a structure of a preferable specific example of the screw type biaxial extrusion dryer 5 shown in fig. 1. The above-described dehydration and drying process can be suitably performed by the screw type biaxial extrusion dryer 5.

The screw type biaxial extrusion dryer 5 shown in fig. 2 is a twin screw type extrusion dryer having a pair of screws not shown in a barrel unit 51. The screw type biaxial extrusion dryer 5 has a drive unit 50 that rotationally drives a pair of screws in a barrel unit 51. With this structure, the acrylic rubber can be dried by applying an optimal shear, which is preferable. The driving unit 50 is installed at the upstream end (left end in fig. 2) of the barrel unit 51. Further, the screw type biaxial extrusion dryer 5 has a die 59 at the downstream end (right end in fig. 2) of the barrel unit 51.

The barrel unit 51 has a supply barrel portion 52, a dehydration barrel portion 53, and a dryer barrel portion 54 from the upstream side to the downstream side (from the left side to the right side in fig. 2).

The supply cylinder portion 52 is composed of 2 supply cylinders, i.e., a first supply cylinder 52a and a second supply cylinder 52 b.

Further, the dehydration cylinder section 53 is constituted by three dehydration cylinders, namely, a first dehydration cylinder 53a, a second dehydration cylinder 53b, and a third dehydration cylinder 53 c.

The dryer section 54 is composed of eight dryer cylinders, namely, a first dryer cylinder 54a, a second dryer cylinder 54b, a third dryer cylinder 54c, a fourth dryer cylinder 54d, a fifth dryer cylinder 54e, a sixth dryer cylinder 54f, a seventh dryer cylinder 54g, and an eighth dryer cylinder 54 h.

The barrel unit 51 is configured such that 13 divided barrels 52a to 52b, 53a to 53c, 54a to 54h are connected from the upstream side to the downstream side.

The screw type biaxial extrusion dryer 5 further includes heating means, not shown, for heating the respective cylinders 52a to 52b, 53a to 53c, 54a to 54h, and for heating the aqueous pellets in the respective cylinders 52a to 52b, 53a to 53c, 54a to 54h to a predetermined temperature. The heating units have numbers corresponding to the respective barrels 52a to 52b, 53a to 53c, 54a to 54 h. As such heating means, for example, a structure is employed in which high-temperature steam or the like is supplied from the steam supply means to the steam flow shields formed in the respective cylinders 52a to 52b, 53a to 53c, 54a to 54h, but the invention is not limited thereto. The screw type biaxial extrusion dryer 5 further includes a temperature control means, not shown, for controlling the set temperatures of the heating means corresponding to the barrels 52a to 52b, 53a to 53c, and 54a to 54 h.

The number of supply cylinders, dewatering cylinders, and drying cylinders constituting the

respective cylinder sections

52, 53, and 54 in the cylinder unit 51 is not limited to the one shown in fig. 2, and may be set to a number corresponding to the water content of the aqueous pellets of the acrylic rubber subjected to the drying treatment.

For example, the number of supply barrels provided in the supply barrel portion 52 is, for example, 1 to 3. The number of the dehydrators of the dehydrator cylinder 53 is preferably 2 to 10, for example, and in the case of 3 to 6, it is more preferable because dehydration of the water-containing pellets of the adhesive acrylic rubber can be efficiently performed. The number of the dryer cylinders of the dryer cylinder section 54 is preferably 2 to 10, more preferably 3 to 8, for example.

The pair of screws in the barrel unit 51 are rotationally driven by a driving unit such as a motor accommodated in the driving unit 50. The pair of screws extend from the upstream side to the downstream side in the barrel unit 51, and by the rotation driving, the aqueous pellets supplied to the supply barrel unit 52 can be conveyed downstream while being mixed. The pair of screws are preferably biaxial meshing type in which the flight portion and the groove portion are in meshing engagement with each other, whereby the dewatering efficiency and drying efficiency of the aqueous pellet can be improved.

The rotation direction of the pair of screws may be the same or different, and it is preferable to rotate in the same direction from the viewpoint of self-cleaning performance. The screw shape of the pair of screws is not particularly limited, and is not particularly limited as long as it is a shape required in each of the

cylinder portions

52, 53, 54.

The supply barrel section 52 is a region in which the aqueous pellets are supplied into the barrel unit 51. The first supply cylinder 52a of the supply cylinder section 52 has a feed port 55 for supplying the aqueous pellets into the cylinder unit 51.

The dewatering cylinder 53 is a region where a liquid (slurry) containing a coagulant or the like is separated from the aqueous pellet and discharged.

The first to third dewatering cylinders 53a to 53c constituting the dewatering cylinder 53 have

dewatering slits

56a, 56b, 56c for discharging the water of the aqueous pellets to the outside, respectively. A plurality of

dewatering slits

56a, 56b, 56c are formed in each dewatering cylinder 53a to 53 c.

The slit width, that is, the mesh width of each

dewatering slit

56a, 56b, 56c may be appropriately selected depending on the conditions of use, and is usually 0.01 to 5mm, preferably 0.1 to 1mm, more preferably 0.2 to 0.6mm, from the viewpoint that the loss of the aqueous pellets is small and the dewatering of the aqueous pellets can be effectively performed.

The removal of water from the hydrous pellets in each of the dewatering cylinders 53a to 53c of the dewatering cylinder 53 includes both the liquid removal from the

respective dewatering slits

56a, 56b, 56c and the vapor removal. The dewatering cylinder 53 of the present embodiment is distinguished by a case where water is removed in a liquid state being referred to as drainage and a case where water is removed in a vapor state being referred to as drainage.

The dehydration cylinder 53 is preferable because the water content of the adhesive acrylic rubber can be reduced efficiently by combining drainage and steam discharge. In the dehydration cylinder portion 53, which dehydration cylinder of the first to third dehydration cylinders 53a to 53c is used for water discharge or steam discharge can be appropriately set according to the purpose of use, and in general, in the case of reducing the ash content in the produced acrylic rubber, it is preferable to increase the dehydration cylinder used for water discharge. In this case, for example, as shown in fig. 2, the first and

second dewatering cylinders

53a, 53b on the upstream side are drained, and the third dewatering cylinder 53c on the downstream side is drained. In the case where, for example, the dewatering cylinder portion 53 has four dewatering cylinders, for example, a mode is considered in which water is discharged from three dewatering cylinders on the upstream side and steam is discharged from 1 dewatering cylinder on the downstream side. On the other hand, in the case of decreasing the water content, it is preferable to increase the dehydration cylinder in which the steam discharge is performed.

As described in the above-described dehydration/drying step, the set temperature of the dehydration cylinder 53 is usually in the range of 60 to 150 ℃, preferably in the range of 70 to 140 ℃, more preferably in the range of 80 to 130 ℃, and the set temperature of the dehydration cylinder for dehydration in a water discharge state is usually 60 to 120 ℃, preferably 70 to 110 ℃, more preferably 80 to 100 ℃, and the set temperature of the dehydration cylinder for dehydration in a steam discharge state is usually in the range of 100 to 150 ℃, preferably 105 to 140 ℃, more preferably 110 to 130 ℃.

The dryer section 54 is a region in which the dehydrated aqueous pellets are dried under reduced pressure. Of the first to eighth dryer barrels 54a to 54h constituting the dryer barrel section 54, the second dryer barrel 54b, the fourth dryer barrel 54d, the sixth dryer barrel 54f, and the eighth dryer barrel 54h have

exhaust ports

58a, 58b, 58c, 58d for degassing, respectively. Exhaust pipes, not shown, are connected to the

exhaust ports

58a, 58b, 58c, 58d, respectively.

A vacuum pump, not shown, is connected to the end of each exhaust pipe, and the interior of the dryer cylinder 54 is depressurized to a predetermined pressure by the operation of these vacuum pumps. The screw extruder 5 has a pressure control unit, not shown, for controlling the operation of these vacuum pumps and controlling the vacuum level in the dryer barrel section 54.

The vacuum degree in the dryer cylinder 54 may be appropriately selected, and is usually set to 1 to 50kPa, preferably 2 to 30kPa, and more preferably 3 to 20kPa as described above.

The temperature to be set in the dryer barrel 54 may be appropriately selected, and is usually set to 100 to 250 ℃, preferably 110 to 200 ℃, and more preferably 120 to 180 ℃ as described above.

In each of the dryer cylinders 54a to 54h constituting the dryer cylinder section 54, the set temperature in all of the dryer cylinders 54a to 54h may be set to an approximate value, or may be different, and it is preferable to set the temperature on the downstream side (the die 59 side) to a higher temperature than the temperature on the upstream side (the dryer cylinder section 53 side) for improving the drying efficiency.

The die 59 is a die disposed at the downstream end of the barrel unit 51 and has a discharge port of a predetermined nozzle shape. The acrylic rubber dried in the dryer cylinder 54 is extruded through the outlet of the die 59 to a shape corresponding to a predetermined nozzle shape. The acrylic rubber passing through the die 59 may be molded into various shapes such as a pellet, a column, a round bar, a sheet, etc., depending on the nozzle shape of the die 59, and in the present invention, it is molded into a sheet. A perforated plate, a metal mesh, or the like may be provided between the screw and the die 59.

The aqueous pellets of the acrylic rubber obtained through the cleaning step are supplied from the feed port 55 to the supply cylinder portion 52. The aqueous pellets supplied to the supply cylinder section 52 are sent from the supply cylinder section 52 to the dehydration cylinder section 53 by rotation of a pair of screws in the cylinder unit 51. In the dewatering cylinder 53, as described above, the

dewatering slits

56a, 56b, and 56c provided in the first to third dewatering cylinders 53a to 53c drain water and steam contained in the aqueous pellets, respectively, and dewater the aqueous pellets.

The aqueous pellets dehydrated in the dehydration barrel section 53 are sent to the dryer barrel section 54 by rotation of a pair of screws in the barrel unit 51. The water-containing pellets sent to the dryer section 54 are plasticized and mixed to form a melt, and are conveyed downstream while being heated by heat release. Then, moisture contained in the melt of the acrylic rubber is vaporized, and the moisture (vapor) is discharged to the outside through exhaust pipes, not shown, connected to the

exhaust ports

58a, 58b, 58c, and 58d, respectively.

As described above, the aqueous pellets are dried by the dryer barrel 54 to obtain a melt of the acrylic rubber, which is supplied to the die 59 by the rotation of the pair of screws in the barrel unit 51, and extruded from the die 59.

Here, an example of the operating conditions of the screw type biaxial extrusion dryer 5 of 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 1000rpm, preferably 50 to 750rpm, more preferably 100 to 500rpm, and most preferably 120 to 300rpm, from the viewpoint of being able to efficiently reduce the water content of the acrylic rubber and the amount of methyl ethyl ketone insoluble components.

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, and most preferably 500 to 800 kg/hr.

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

The maximum torque in the cylinder unit 51 is not particularly limited, but is usually in the range of 5 to 125 N.m, preferably 10 to 100 N.m, more preferably 10 to 50 N.m, and particularly preferably 15 to 45 N.m.

The specific energy consumption in the cylinder unit 51 is not particularly limited, but is usually in the range of 0.01 to 0.3[ kw.h/kg ], preferably 0.05 to 0.25[ kw.h/kg ], more preferably 0.1 to 0.2[ kw.h/kg ].

The specific power in the cylinder unit 51 is not particularly limited, but is usually in the range of 0.1 to 0.6[ A.multidot.h/kg ], preferably 0.15 to 0.55[ A.multidot.h/kg ], more preferably 0.2 to 0.5[ A.multidot.h/kg ].

The shear rate in the barrel unit 51 is not particularly limited, but is usually 5 to 150[1/s ] or more, preferably 10 to 100[1/s ], and more preferably 25 to 75[1/s ].

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

The cooling device 6 shown in fig. 1 is configured to cool the dried rubber obtained through the dehydration step by a dehydrator and the drying step by a dryer. As the cooling method by the cooling device 6, various methods including an air cooling method by blowing or cooling air, a water spraying method, a dipping method in water, and the like can be used. In addition, the rubber may also be dried by cooling at room temperature.

As described above, the dried rubber discharged from the screw extruder 5 is extruded into various shapes such as pellets, columns, round bars, sheets, etc., according to the nozzle shape of the die 59, and is molded into a sheet in the present invention. Hereinafter, a description will be given of a conveyor type cooling device 60 as an example of the cooling device 6 with reference to fig. 3, and the conveyor type cooling device 60 cools the sheet-shaped dry rubber 10 molded into a sheet shape.

Fig. 3 shows a structure of a preferred transport type cooling device 60 as the cooling device 6 shown in fig. 1. The conveying type cooling device 60 shown in fig. 3 is configured to cool by an air cooling system while conveying the sheet-like dry rubber 10 discharged from the discharge port of the die 59 of the screw extruder 5. By using this conveyor cooling device 60, the sheet-like dry rubber discharged from the screw extruder 5 can be cooled appropriately.

The conveying 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, for example, or is provided in the vicinity of the die 59.

The conveying type cooling device 60 has a conveyor 61 that conveys the sheet-like dry rubber 10 discharged from the die 59 of the screw type extruder 5 in the direction of arrow a in fig. 3, and a cooling unit 65 that blows cool air to the sheet-like dry rubber 10 on the conveyor 61.

The conveyor 61 includes

rollers

62 and 63, and a conveyor belt 64 wound around the

rollers

62 and 63 in tension and having the sheet-like dry rubber 10 placed thereon. The conveyor 61 is configured to continuously convey the sheet-like dried rubber 10 discharged from the die 59 of the screw extruder 5 to the downstream side (right side in fig. 3) on the conveyor belt 64.

The cooling unit 65 is not particularly limited, and examples thereof include a cooling unit having a structure in which cooling air sent from a cooling air generating unit, not shown, is blown onto the surface of the sheet-like dry rubber 10 on the conveyor belt 64.

The length L1 of the conveyor 61 and the cooling unit 65 of the transport type cooling device 60 (the length of the portion capable of blowing cooling air) is not particularly limited, and is, for example, 10 to 100m, preferably 20 to 50m. The conveying speed of the sheet-like dry rubber 10 in the conveying type cooling device 60 may be appropriately adjusted according to the length L1 of the conveyor 61 and the cooling unit 65, the discharge speed of the sheet-like dry rubber 10 discharged from the die 59 of the screw extruder 5, the target cooling speed, the cooling time, and the like, and is, for example, 10 to 100 m/hr, and more preferably 15 to 70 m/hr.

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

The transport cooling device 60 is not particularly limited to the configuration having 1

conveyor

61 and 1 cooling unit 65 shown in fig. 3, and may have a configuration having 2 or more conveyors 61 and 2 or more cooling units 65 corresponding thereto. In this case, the total length of each of the 2 or more conveyors 61 and the cooling unit 65 may be set to the above range.

The rubber packing device 7 shown in fig. 1 is configured to process the dried rubber extruded from the screw extruder 5 and cooled by the cooling device 6 to manufacture a one-piece rubber pack. As described above, the screw extruder 5 can extrude the dried rubber into various shapes such as pellets, columns, round bars, and sheets, and the rubber packing device 7 is configured to pack the dried rubber thus molded into various shapes. The weight, shape, etc. of the rubber-coated acrylic rubber produced by the rubber coating device 7 are not particularly limited, and for example, approximately 20kg of a rubber-coated acrylic rubber having a substantially rectangular parallelepiped shape can be produced.

The rubber packing device 7 has, for example, a packer, and can manufacture rubber-packed acrylic rubber by compressing cooled dry rubber using the packer.

In addition, in the case of producing the sheet-like dry rubber 10 by the screw extruder 5, a rubber-coated acrylic rubber in which the sheet-like dry rubber 10 is laminated can be produced. For example, a cutter mechanism for cutting the sheet-like dried rubber 10 may be provided in the rubber packing device 7 disposed downstream of the conveyor-type cooling device 60 shown in fig. 3. Specifically, the cutting mechanism of the rubber packing device 7 is configured to cut the cooled sheet-like dry rubber 10 continuously at predetermined intervals, for example, and process the sheet-like dry rubber 16 into a predetermined size. The plurality of pieces of the sliced dried rubber 16 cut into a predetermined size by the cutting mechanism are stacked, whereby the rubber-covered acrylic rubber in which the sliced dried rubber 16 is stacked can be produced.

In the case of producing a rubber-coated acrylic rubber in which the sliced dried rubber 16 is laminated, it is preferable to laminate the sliced dried rubber 16 at 40 ℃ or higher, for example. By stacking the sliced dried rubber 16 at 40 ℃ or higher, air can be satisfactorily removed by further cooling and compression by its own weight.

Examples

Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples. In each example, "parts", "%" and "ratio" are weight basis unless otherwise specified. Further, various physical properties and the like were evaluated by the following methods.

[ monomer composition ]

Regarding the monomer composition in the acrylic rubber, use is made of ¹ The monomer structure of each monomer unit in the acrylic rubber was confirmed by H-NMR, and the residual reactivity of the reactive group in the acrylic rubber and the content of each reactive group were confirmed by the following method. The content ratio of each monomer unit in the acrylic rubber is calculated from the amount of each monomer used for polymerization reaction and the polymerization conversion rate. Specifically, since the polymerization reaction is an emulsion polymerization reaction and the polymerization conversion rate is approximately 100% which cannot be confirmed by the unreacted monomers, the content ratio of each monomer unit in the rubber is the same as the amount of each monomer used.

[ reactive group content ]

The content of the reactive group in the acrylic rubber bag was determined by the following method.

(1) The carboxyl group amount was calculated as follows: the sample (acrylic rubber bag) was dissolved in acetone, and potentiometric titration was performed with potassium hydroxide solution to obtain the product.

(2) The epoxy group amount was calculated as follows: the sample was dissolved in methyl ethyl ketone, an equivalent amount of hydrochloric acid was added thereto, and reacted with an epoxy group, and the amount of residual hydrochloric acid was titrated with potassium hydroxide.

(3) The chlorine content was calculated as follows: the sample was completely burned in a burning flask, and the generated chlorine was absorbed in water and titrated with silver nitrate.

[ Ash content ]

The ash content (%) contained in the acrylic rubber bag was measured in accordance with JIS K6228A method.

[ ash component amount ]

The amount (%) of each component in the acrylic rubber-coated ash was calculated as the ratio of the ash by pressing the ash collected at the time of measuring the ash against titration filter paper having a diameter of 20mm and measuring the amount (ppm) of the component using ZSX Primus (manufactured by the company of the chemical company).

[ molecular weight and molecular weight distribution ]

The molecular weight (Mw, mn, mz) and the molecular weight distribution (Mw/Mn and Mz/Mw) of the acrylic rubber are the absolute molecular weight and the absolute molecular weight distribution measured by GPC-MALS method in which a solution in which lithium chloride and 37% concentrated hydrochloric acid are added to dimethylformamide respectively to have a concentration of 0.05mol/L and a concentration of hydrochloric acid of 0.01% is used as a solvent. The "GPC-MALS method" is as follows. GPC (gel permeation chromatography: gel permeation chromatography) is a liquid chromatography that separates based on differences in molecular size, specifically the following method: a multi-angle laser light scattering photometer (MALS) and a differential Refractometer (RI) were incorporated in a GPC (Gel Permeation Chromatography) apparatus, and the light scattering intensity and refractive index difference of a molecular chain solution classified by size were measured by a GPC apparatus in accordance with the elution time, whereby the molecular weight of a solute and the content thereof were sequentially calculated, and finally the absolute molecular weight distribution and absolute average molecular weight value of a polymer substance were obtained.

The main device of the gel permeation chromatograph multi-angle light scattering photometer was composed of a pump (manufactured by LC-20ADOpt corporation, shimadzu), a differential refractometer (manufactured by Optilab re Huai Ya trickplay) as a detector, and a multi-angle light scattering detector (manufactured by DAWN HELEOS Huai Ya trickplay).

Thus, the molecular weight of the solute and the content thereof were calculated sequentially. The measurement conditions and measurement methods using the GPC apparatus are as follows.

Column: TSKgel alpha-M2 root%

Tosoh Co., ltd

Column temperature: 40 DEG C

Flow rate: 0.8ml/mm

Sample preparation: to a 10mg sample, 5ml of a solvent was added, and the mixture was stirred slowly at room temperature (dissolution was visually confirmed). Then, filtration was performed using a 0.5 μm filter.

[ glass transition temperature (Tg) ]

The glass transition temperature (Tg) of the acrylic rubber was measured by a differential scanning calorimeter (DSC, product name "X-DSC7000", manufactured by Hitachi high technology science, inc.).

[ gel amount ]

The gel content (%) of the acrylic rubber bag was an amount insoluble in methyl ethyl ketone component, and was determined by the following method.

About 0.2g (Xg) of an acrylic rubber bag was weighed, immersed in 100ml of methyl ethyl ketone, left at room temperature for 24 hours, and then the methyl ethyl ketone-insoluble component was filtered through a 80-mesh metal mesh to obtain a filtrate in which only the methyl ethyl ketone-soluble rubber component was dissolved, and the filtrate was evaporated, dried and solidified to obtain a dry solid component (Yg) by weighing the obtained dry solid component (Yg), which was calculated by the following formula.

Gel amount (%) =100× (X-Y)/X

[ specific gravity ]

The specific gravity of the acrylic rubber bag was measured in accordance with JIS K6268 crosslinked rubber-A method of density measurement.

The measured value obtained by the following measuring method was the density, but the density of water was set to 1Mg/m ³ To obtain specific gravity. Specifically, the specific gravity of the rubber sample obtained by the A method of JIS K6268 crosslinked rubber-density measurement is obtained by dividing the mass of the rubber sample by the volume containing voidsThe obtained value is obtained by dividing the density of a rubber sample measured by the method A of crosslinked rubber-density measurement according to JIS K6268 by the density of water (if the density of the rubber sample is divided by the density of water, the values are the same and the unit is lost). Specifically, the specific gravity of the rubber sample was determined based on the following procedure.

(1) 2.5g of a test piece was cut out from a rubber sample left standing at a standard temperature (23 ℃ C.+ -. 2 ℃ C.) for at least 3 hours, and the test piece was hung from a hanger on a chemical balance having an accuracy of 1mg in such a manner that the bottom edge of the test piece was 25mm or more from a tray for the chemical balance using a fine nylon wire having a mass of less than 0.010g, and the mass (m 1) of the test piece was measured twice in the atmosphere to mg.

(2) Next, 250cm of the solution was placed on a tray for a chemical balance ³ The beaker was filled with distilled water which was boiled and cooled to a standard temperature, the test piece was immersed therein, bubbles adhering to the surface of the test piece were removed, the movement of the hand of the balance was observed for several seconds, it was confirmed that the hand was not gently swung by convection, and the mass (m 2) of the test piece in water was measured twice in mg.

(3) In addition, the density of the test piece is less than 1Mg/m ³ When (when the test piece floats in water), a weight is added to the test piece, and the weight (m 3) of the weight and the weight (m 4) of the test piece and the weight in water are measured twice in mg.

(4) The specific gravity of the rubber sample was measured using the average value of m1, m2, m3, and m4, and the density (Mg/m) was calculated based on the following formula ³ ) The calculated density was divided by the water density (1.00 Mg/m ³ ) And the result was obtained.

(Density of rubber sample without counterweight)

Density=m1/(m 2-m 2)

(Density of rubber sample when weight was used)

Density=m1/(m1+m3-m 4)

[ Water content ]

Moisture content (%) according to JIS K6238-1: oven a (volatile component measurement) method.

[pH]

Regarding the pH, after 6g (+ -0.05 g) of the acrylic rubber was dissolved in 100g of tetrahydrofuran, 2.0ml of distilled water was added thereto, and after confirming complete dissolution, measurement was performed by a pH electrode.

[ Complex viscosity ]

The complex viscosity η was determined by measuring the temperature dispersion (40 to 120 ℃) at a deformation of 473% and 1Hz using a dynamic viscoelasticity measuring device "rubber processing analyzer RPA-2000" (manufactured by alpha technologies Co., ltd.). Here, the ratio η (100 ℃) to η (60 ℃) was calculated by taking the dynamic viscoelasticity at 60℃as the complex viscosity η (60 ℃) and the dynamic viscoelasticity at 100℃as the complex viscosity η (100 ℃).

[ Mooney viscosity (ML1+4, 100 ℃)

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

[ injection moldability ]

The injection moldability was evaluated by observing and scoring the shape formability, releasability and fusion property by using a small injection molding machine (SLIM 15-30: manufactured by Kyowa Co., ltd.), and comprehensively evaluating the total score thereof according to the following criteria. Shape formability and releasability were evaluated as follows: three cylindrical shapes (a:

B：

C：/>

) The rubber composition was introduced into the mold under conditions of a screw temperature of 90℃for 30 seconds and an injection pressure of 7MPa, and the molded article having a cylindrical shape was obtained by injection molding after crosslinking at a mold temperature of 170℃for 1 minute and 30 seconds, and the molded article having a cylindrical shape and the mold were observed and scored according to the following criteria. The fusibility was evaluated as follows: is prepared to imitate that the two ends of the length direction are respectively connected with +. >

A metal mold for a fusion observation belt having a thickness of 0.5mm by 5mm by 40mm by 5mm in length, wherein the rubber composition was allowed to flow from +.>

The tubes of (2) were each fed into a fusion observation zone, crosslinked at a mold temperature of 170℃for 1 minute and 30 seconds, and then the fusion state of the rubber composition in the fusion observation body was observed, and the evaluation was performed according to the following criteria.

(shape Forming Property)

5, the method comprises the following steps: the cylindrical molded article was produced by A, B, C, and the shape of the tip end portion of the entire molded article was formed completely corresponding to the mold, and formation of burrs was not confirmed.

4, the following steps: while a cylindrical molded article can be produced by A, B, C, a small portion of the tip end of the molded article cannot completely correspond to the shape of the metal mold by C.

3, the method comprises the following steps: a cylindrical molded article can be produced by A, B, and a molded article of half or more can be produced by C

2, the method comprises the following steps: a cylindrical molded article can be produced by A, B, but even half of the C-shaped article cannot be produced

1, the method comprises the following steps: a can produce a molded article, but B cannot completely produce a molded article

0 point: a is not used for producing molded articles

(Release property)

5, the method comprises the following steps: can be easily released from the metal mold without mold residue

4, the following steps: can be easily released from the metal mold, but only slight mold residues are visible

3, the method comprises the following steps: can be easily released from the metal mold, but has a small amount of mold residue

2, the method comprises the following steps: slightly difficult to be peeled from the metal mold, but no mold remains

1, the method comprises the following steps: slightly difficult to be separated from the metal mold and mold residues are also present

0 point: difficult to be peeled from a metal mold

(fusibility)

5, the method comprises the following steps: complete fusion

0 point: incomplete fusion (poor fusion)

Comprehensive evaluation

And (3) the following materials: full score (15 score)

And (2) the following steps: 14 minutes

And ∈:13 minutes

Delta: 11-12 minutes

X: less than 10 minutes

[ Banbury processability ]

The banbury processability of the rubber samples was evaluated as follows: the rubber sample was put into a Banbury mixer heated to 50℃for mastication for 1 minute, and then compounding agent A of the rubber mixture formulation shown in Table 1 was put into the mixer, and the time until the rubber mixture at the first stage was integrated and the maximum torque value, that is, BIT (Black Incorporation Time: carbon black mixing time) was measured, and the index of 100 in comparative example 2 was calculated and evaluated on the basis of the following criteria.

And (3) the following materials: 20 or less

And (2) the following steps: greater than 20 and less than 40

And ∈: greater than 40 and less than 60

Delta: more than 60 and less than 80

X: greater than 80

[ evaluation of storage stability ]

The storage stability of the rubber sample was evaluated as follows: the rubber sample was placed in a constant temperature and humidity tank (SH-222, manufactured by ESPEC Co., ltd.) at 45℃with 80% RH, the rate of change in water content before and after 7 days of the test was calculated, the index of 100 was calculated, and the evaluation was performed on the basis of the following.

And (3) the following materials: 20 or less

And (2) the following steps: greater than 20 and less than 50

And ∈: greater than 50 and less than 90

Delta: greater than 90 and less than 100

X: greater than 100

[ evaluation of Water resistance ]

The water resistance of the rubber sample was evaluated as follows: the crosslinked product of the rubber sample was immersed in distilled water at 85℃for 100 hours in accordance with JIS K6258 to conduct an immersion test, and the volume change rate before and after the immersion was measured, and the index was calculated to be 100 in comparative example 2, and evaluated according to the following criteria.

And (3) the following materials: 1 or less

And (2) the following steps: greater than 1 and less than 5

And ∈: more than 5 and less than 10

Delta: more than 10 and less than 50

X: greater than 50

[ compression set resistance ]

The compression set resistance of the rubber sample was evaluated by the following means: the compression set was measured after leaving the rubber crosslinked product of the rubber sample compressed by 25% in accordance with JIS K6262 at 175℃for 90 hours, and evaluated according to the following criteria.

And (3) the following materials: compression set of less than 15%

X: compression set of 15% or more

[ evaluation of physical Properties in Normal state ]

The normal physical properties of the rubber sample were evaluated in accordance with JIS K6251, and the breaking strength, 100% tensile stress and elongation at break of the rubber crosslinked product of the rubber sample were measured and evaluated in accordance with the following criteria.

(1) The fracture strength was evaluated as excellent at 10MPa or more and as X at less than 10 MPa.

(2) 100% tensile stress was evaluated as excellent at 5MPa or more and less than 5MPa as X.

(3) The elongation at break was evaluated as excellent at 150% or more and as X at less than 150%.

[ evaluation of deviation of gel amount ]

The deviation of the gel amount of the rubber sample was evaluated as follows: the gel amount at 20 points arbitrarily selected from 20 parts (20 kg) of the rubber sample was measured, and evaluated based on the following criteria.

And (3) the following materials: calculating the average value of the gel amounts at 20 points, wherein all the 20 points are within the range of + -3 of the average value

And (2) the following steps: calculating the average value of the gel amounts at 20 points of measurement, wherein the values at 20 points of measurement are all within the range of the average value.+ -. 5 (even if only 1 point of the 20 points of measurement is outside the range of the average value.+ -. 3, the values at 20 points are all within the range of the average value.+ -. 5)

X: calculating the average value of the gel amounts at 20 positions, wherein 1 of the 20 positions is out of the range of + -5 of the average value

[ evaluation of processing stability of Mooney scorch inhibition ]

The mooney scorch storage stability of the acrylic rubber composition was evaluated with respect to the cooling rate of the sheet-like acrylic rubber extruded from the screw type biaxial extrusion dryer described in japanese patent No. 6683189.

Example 1

As shown in Table 2-1, 46 parts of pure water, 48.5 parts of ethyl acrylate as a monomer component, 50 parts of n-butyl acrylate and 1.5 parts of mono-n-butyl fumarate, 1.8 parts of sodium tridecyloxy hexaoxyethylene phosphate as an emulsifier were added to a mixing vessel having a homogenizer, and stirred to obtain a monomer emulsion.

Into a polymerization reaction vessel equipped with a thermometer and a stirring device, 170 parts of pure water and 3 parts of the monomer emulsion obtained above were charged, and after cooling to 12℃under a nitrogen stream, 0.00033 parts of ferrous sulfate, 0.02 parts of sodium ascorbate, and 0.0045 parts of diisopropylbenzene hydroperoxide as an organic radical generator were added to initiate polymerization. The polymerization was continued by continuously dropping the remaining part of the monomer emulsion at 23℃for 3 hours, adding 0.012 parts of n-dodecyl mercaptan after 50 minutes from the start of the reaction, adding 0.012 parts of n-dodecyl mercaptan after 100 minutes, and adding 0.4 parts of sodium L-ascorbate after 120 minutes, and stopping the polymerization by adding hydroquinone as a polymerization terminator when the polymerization conversion reached about 100%, to obtain an emulsion polymerization solution.

Next, in a coagulation tank having a thermometer and a stirring device, the emulsion polymerization liquid obtained above was heated to 80 ℃, 350 parts of a 2% magnesium sulfate aqueous solution (coagulation liquid using magnesium sulfate as a coagulant) heated to 80 ℃ and vigorously stirred at a stirring blade rotation speed of 600 revolutions (circumferential speed 3.1 m/s) of the stirring device was continuously added, and the polymer was coagulated to obtain a coagulated slurry containing aggregates of acrylic rubber as a coagulated material and water. The pellets were filtered from the resulting slurry, while water was drained from the solidified layer, to obtain aqueous pellets.

194 parts of hot water (70 ℃) was added to the coagulation tank in which the filtered aqueous pellets remained, stirred for 15 minutes, the aqueous pellets were washed, then the water was discharged, 194 parts of hot water (70 ℃) was added again, stirred for 15 minutes, and the aqueous pellets were washed (the total number of washing times was two). The washed aqueous pellet (aqueous pellet temperature 65 ℃) was supplied to a screw type biaxial extrusion dryer 15, dehydrated and dried, and a sheet-like dried rubber having a width of 300mm and a thickness of 10mm was extruded. Next, the sheet-like dry rubber was cooled at a cooling rate of 200 ℃/hr using a conveyor type cooling device provided in direct connection with the screw type biaxial extrusion dryer 15.

The screw type biaxial extrusion dryer used in example 1 was composed of one supply cylinder, three dehydration cylinders (first to third dehydration cylinders), and five dryer cylinders (first to fifth dryer cylinders). The first dewatering cylinder discharges water, and the second and third dewatering cylinders discharge steam. The screw type biaxial extrusion dryer was operated as follows. The post-dewatering (drainage) water content, maximum torque, specific power, specific energy consumption, shear rate and shear viscosity of the screw type biaxial extrusion dryer are shown in table 2-1.

Water content:

water content of the aqueous pellet after draining with the first dewatering barrel: 20 percent of

Water content of the aqueous pellets after steam venting with the third dewatering barrel: 10 percent of

Moisture content of the aqueous pellet after drying with the fifth dryer barrel: 0.4%

Rubber temperature:

temperature of the aqueous pellets fed to the feed barrel: 65 DEG C

Temperature of rubber discharged from screw type biaxial extrusion dryer: 140 DEG C

Set temperature of each barrel:

first dewatering barrel: 100 DEG C

A second dewatering barrel: 120 DEG C

Third dewatering barrel: 120 DEG C

First dryer barrel: 120 DEG C

Second dryer barrel: 130 DEG C

Third dryer barrel: 140 DEG C

Fourth dryer barrel: 160 DEG C

Fifth dryer barrel: 180 DEG C

Operating conditions:

diameter of screw (D): 132mm

Full length of screw (L): 4620mm

·L/D：35

Rotational speed of the screw: 135rpm

Vacuum of the dryer barrel: 10kPa

The amount of rubber extruded from the die: 700 kg/hr

Resin pressure of die: 2MPa of

Maximum torque in screw type biaxial extrusion dryer: 40 N.m

The extruded sheet-like dry rubber was cooled to 50℃and then cut by a cutter, and 20 parts (20 kg) of the sheet-like dry rubber was laminated before the temperature was lowered to 40℃or lower, to obtain an acrylic rubber bag (A). The reactive group content, ash component content, gel content, pH, specific gravity, glass transition temperature (Tg), water content, molecular weight distribution, and complex viscosity at 100℃and 60℃of the obtained acrylic rubber bag (A) were measured and are shown in tables 2-2. Further, the storage stability test of the acrylic rubber bag (A) was conducted to determine the water content change rate, and the results are shown in Table 2-2.

Next, 100 parts of the acrylic rubber bag (A) and the compounding agent A of "formulation 1" shown in Table 1 were charged into a Banbury mixer, and mixed at 50℃for 5 minutes (first-stage mixing). At this time, BIT was measured, and the Banbury processability was evaluated, and the results are shown in Table 2-2. Next, the resulting mixture was transferred to a roller at 50℃and compounded with compounding agent B of "formula 1" shown in Table 1 and mixed (second stage mixing) to obtain a rubber composition. The obtained rubber compositions were evaluated for injection moldability, and the results are shown in tables 2-2.

TABLE 1

1: SEAST3 (HAF) in the table is carbon black (manufactured by eastern sea carbon Co., ltd.).

2: NOCRAC CD in the tables is 4,4' -bis (. Alpha.,. Alpha. -dimethylbenzyl) diphenylamine (manufactured by Dain Ind Chemie Co., ltd.).

3: rhenotran XLA-60 in the table is a vulcanization accelerator (manufactured by Lang Cheng Zhushi Co., ltd.).

Next, the remaining rubber composition was placed in a metal mold having a length of 15cm, a width of 15cm and a depth of 0.2cm, and the resultant was pressed at 180℃for 10 minutes while being pressurized at a pressing pressure of 10MPa, thereby performing primary crosslinking, and the obtained primary crosslinked product was heated further at 180℃for 2 hours in a Gill oven to be secondarily crosslinked, thereby obtaining a sheet-shaped rubber crosslinked product. Then, a test piece of 3 cm. Times.2 cm. Times.0.2 cm was cut out from the resulting sheet-like crosslinked rubber, and the water resistance, compression set resistance and normal physical properties were evaluated. The results are shown in Table 2-2.

Example 2

An acrylic rubber bag (B) was obtained in the same manner as in example 1 except that 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 as shown in Table 2-1, and the properties (compounding agent was changed to "formula 2" (see Table 1) were evaluated.

Example 3

An acrylic rubber bag (C) was obtained in the same manner as in example 1, except that the post-addition of n-dodecyl mercaptan was changed to 0.008 parts after 50 minutes, 0.008 parts after 100 minutes, and 0.008 parts after 120 minutes three times in total, and each characteristic was evaluated. These results are shown in Table 2-2.

Example 4

An acrylic rubber bag (D) was obtained in the same manner as in example 2, except that the post-addition of n-dodecyl mercaptan was changed to 0.008 parts after 50 minutes, 0.008 parts after 100 minutes, and 0.008 parts after 120 minutes three times in total, and each characteristic was evaluated. These results are shown in Table 2-2.

Example 5

An acrylic rubber bag (E) was obtained in the same manner as in example 1 except that the maximum torque of the screw type biaxial extrusion dryer was changed to 15 N.multidot.m as shown in Table 2-1, and each characteristic was evaluated. These results are shown in Table 2-2.

Example 6

An acrylic rubber bag (F) was obtained and each characteristic was evaluated in the same manner as in example 2 except that the maximum torque of the screw type biaxial extrusion dryer was changed to 15 N.m. These results are shown in Table 2-2.

Example 7

An acrylic rubber bag (G) was obtained in the same manner as in example 5 except that the water content after dehydration in the dehydration cylinder portion of the screw type biaxial extrusion dryer was set to 30% by weight, and each characteristic was evaluated. These results are shown in Table 2-2.

Example 8

An acrylic rubber bag (H) was obtained in the same manner as in example 6 except that the water content after dehydration in the dehydration cylinder portion of the screw type biaxial extrusion dryer was set to 30% by weight, and each characteristic was evaluated. These results are shown in Table 2-2.

Reference example 1

An acrylic rubber bag (I) was obtained in the same manner as in example 2 except that the washed aqueous pellets were dried by a hot air dryer at 160℃until the water content was 0.4%, and then packed in a 300X 650X 300mm packer to prepare a rubber-covered acrylic rubber by compacting at a pressure of 3MPa for 25 seconds. The properties of the acrylic rubber bag were evaluated, and the results are shown in tables 2 to 2.

Reference example 2

An acrylic rubber bag (J) was obtained in the same manner as in reference example 1 except that the monomer components were changed to 28 parts of ethyl acrylate, 38 parts of n-butyl acrylate, 27 parts of methoxyethyl acrylate, 5 parts of acrylonitrile and 2 parts of allyl glycidyl ether, and each characteristic was evaluated (the compounding agent was changed to "formula 3" (see table 1)). These results are shown in Table 2-2.

Reference example 3

An acrylic rubber bag (K) was obtained in the same manner as in reference example 1 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 chloride acetate, and each characteristic was evaluated (the compounding agent was changed to "formula 4" (see table 1)). These results are shown in Table 2-2.

Reference example 4

The procedure of reference example 3 was repeated except that the post-addition of n-dodecyl mercaptan was changed to 0.008 parts after 50 minutes, 0.008 parts after 100 minutes, and 0.008 parts after 120 minutes three times in total, to obtain an acrylic rubber bag (L), and each property was evaluated. These results are shown in Table 2-2.

Reference example 5

An acrylic rubber bag (M) was obtained and evaluated for each characteristic in the same manner as in reference example 3 except that the diisopropylbenzene hydroperoxide was changed to 0.0048 parts and 0.024 parts of n-dodecylmercaptan was continuously added to the monomer emulsion without post-addition. These results are shown in Table 2-2.

Comparative example 1

An acrylic rubber in pellet form (N) was obtained in the same manner as in reference example 5 except that a coagulation reaction was carried out by adding a 0.7% aqueous solution of magnesium sulfate to the stirred emulsion polymerization solution (stirring number: 100rpm, circumferential speed: 0.5 m/s) after emulsion polymerization, and the acrylic rubber was not subjected to rubber-encapsulation by a packer to obtain a pellet-like acrylic rubber, and each characteristic was evaluated. These results are shown in Table 2-2.

Comparative example 2

The procedure of comparative example 1 was repeated except that the amount of diisopropylbenzene hydroperoxide was changed to 0.005 part and a chain transfer agent was not added, to obtain a pellet-like acrylic rubber (O), and each property was evaluated. These results are shown in Table 2-2.

[ Table 2-1]

[ Table 2-2]

As is clear from tables 2 to 2, the acrylic rubber compositions (A) to (H) comprising the ionic reactive group of the present invention were excellent in normal physical properties including Banbury workability, water resistance, compression set resistance and strength characteristics, and also excellent in injection moldability and storage stability, in which the gel content of the methyl ethyl ketone insoluble component at 20 was 15% by weight or less, the gel content of the methyl ethyl ketone insoluble component at 20 was arbitrarily measured and all values thereof were within the range of (average.+ -. 5) by weight, the pH was 6 or less, the ash content was 0.0005% or more and 0.2% or less by weight, and the total amount of sodium, sulfur, calcium, magnesium and phosphorus in the ash was 90% or more.

As is clear from tables 2 to 2, the acrylic rubber bags (A) to (M) and the pellet-like acrylic rubbers (N) to (O) of the examples and the reference examples of the present invention have an ion-reactive group of a carboxyl group, an epoxy group or a chlorine atom, and thus are excellent in compression set resistance, and further, since the number average molecular weight (Mn) is more than 50 ten thousand and the weight average molecular weight (Mw) is far more than 100 ten thousand, they are excellent in normal physical properties including strength characteristics (examples 1 to 8, reference examples 1 to 5 and comparative examples 1 to 2). However, the pellet-like acrylic rubber (N) to (O) was poor in banbury processability, injection moldability, water resistance and storage stability (comparative examples 1 to 2).

As is clear from tables 2-1 and 2-2, regarding the Banbury processability, the gel content of the methyl ethyl ketone insoluble component was correlated (comparison of examples 1 to 8, reference examples 1 to 5 and comparative examples 1 to 2). It can be seen that: the gel amount of the methyl ethyl ketone insoluble component of the acrylic rubber can be reduced by emulsion polymerization in the presence of the chain transfer agent (comparison of reference examples 1 to 5 and comparative example 1 with comparative example 2), and particularly when the polymerization conversion is improved in order to improve the strength characteristics, the gel amount of the methyl ethyl ketone insoluble component is drastically increased, so that the gel formation of the methyl ethyl ketone insoluble component can be suppressed in reference examples 1 to 5 in which the chain transfer agent is added after the latter half of the polymerization reaction. The gel amount of the acrylic rubber bag was further significantly reduced by extrusion-drying the aqueous pellet in a molten state having a moisture content of substantially less than 1 wt% in a screw type biaxial extrusion dryer, and the banbury processability was greatly improved without impairing the strength characteristics of the produced acrylic rubber bag (examples 1 to 8 compared with reference examples 1 to 5). In the present invention, although not shown in the present example, it was confirmed that the gel amount of methyl ethyl ketone insoluble component (comparative examples 1 to 2) which increases sharply in emulsion polymerization without adding a chain transfer agent was eliminated by melt kneading in a screw type biaxial extrusion dryer in a state of substantially no moisture (moisture content less than 1% by weight), and the banbury processability was greatly improved.

As is clear from tables 2 to 2, the acrylic rubber packs (A) to (H) of the present invention are excellent in terms of water resistance (examples 1 to 8 and comparative examples 1 to 5 and comparative examples 1 to 2), wherein the acrylic rubber packs (A) to (F) > acrylic rubber packs (G) to (H) > acrylic rubber (packs I) to (J) > acrylic rubber packs (K) to (M) are very excellent in the order of acrylic rubber packs (A) to (F) > acrylic rubber packs (comparative examples 1 to 8 and comparative examples 1 to 5), and they have a large influence on the ash amount in the acrylic rubber (examples 1 to 8, comparative examples 1 to 5 and comparative examples 1 to 2).

As is clear from tables 2-1 and 2-2, the ash content in the acrylic rubber bag can be significantly reduced by changing the method (Lx ∈) in which the concentration of the coagulating liquid is increased (2%) during the coagulation reaction and the emulsion polymerization liquid is added to the stirred coagulating liquid, and the coagulating liquid is vigorously stirred (stirring number 600 rpm/circumferential speed 3.1 m/s) (comparison of reference examples 1 to 5 and comparative example 1). This is presumably because, in particular, the emulsion polymerization liquid is added to the very vigorously stirred coagulation liquid to carry out the coagulation reaction, and the particle diameter of the aqueous aggregates produced in the coagulation reaction is concentrated in the range of a small particle diameter of 710 μm to 4.75mm, as described later, whereby the washing efficiency with hot water and the removal efficiency of the emulsifier and coagulant at the time of dehydration are remarkably improved, the ash content in the acrylic rubber bag is reduced, and the water resistance is remarkably improved. In addition, although the gray levels of reference examples 1 to 5 were equivalent in terms of water resistance, the acrylic rubber packs (I) to (J) were more excellent than the acrylic rubber packs (K) to (M). From these results, it was found that the acrylic rubber bag having carboxyl groups and epoxy groups was more excellent in terms of water resistance than the chlorine atoms in the ion-reactive groups (comparison of reference examples 1 to 2 and reference examples 3 to 5).

As is clear from tables 2-1 and 2-2, regarding the water resistance, by dehydrating (squeezing out moisture) before drying the aqueous pellets, the ash content in the acrylic rubber bag can be further greatly reduced, the water resistance can be remarkably improved (comparison of examples 1 to 8 with reference examples 1 to 5), and it is clear that when more moisture is squeezed out of the aqueous pellets as the water content after dehydration is 20% than the water content after dehydration is 30%, the ash content can be reduced, and the water resistance of the acrylic rubber bag can be remarkably improved (comparison of examples 1 to 6 with examples 7 to 8).

As is clear from tables 2-1 and 2-2, the total amount of phosphorus (P), magnesium (Mg), sodium (Na), calcium (Ca) and sulfur (S) in the ash components of the acrylic rubber packages (a) to (M) of the examples and the reference examples of the present invention and the pellet-like acrylic rubbers (N) to (O) of the comparative examples is 80 wt% or more or 90 wt% or more, and if the ash components can be reduced, the water resistance can be improved. When the ash component is these components, the release properties of the acrylic rubber are particularly excellent. As is clear from tables 2 to 2, the ash content of the acrylic rubber bags (A) to (M) of the examples and reference examples of the present invention after solidification, washing and dehydration by the method of the present invention was 80% or more or 90% by phosphorus (P) and magnesium (Mg) Above (examples 1 to 8, reference examples 1 to 5 and comparative examples 1 to 2). This shows that the ash in the acrylic rubber bag is not directly remained as the emulsifier and coagulant used in the production, but the Na phosphate salt of the emulsifier and magnesium sulfate (MgSO) of the coagulant at the time of the coagulation reaction ₄ ) Although the ash content in the acrylic rubber bag was not sufficiently removed in the washing step by performing salt exchange, the ash content in the acrylic rubber bag, which was present in the aqueous pellets as a phosphate Mg salt which was difficult to be water-soluble, could be reduced by dehydrating (extruding water from the aqueous pellets) in a screw type biaxial extrusion dryer (examples 1 to 8), and the ash content could be reduced and the water resistance of the acrylic rubber bag was significantly improved by extruding more water from the aqueous pellets when the water content after dehydration was 20% as compared with the case where the water content after dehydration was 30% (comparison between examples 1 to 6 and examples 7 to 8).

In the present invention, although the data is omitted in the examples, if a phosphate salt is used as an emulsifier, the water resistance is hardly reduced in the washing step, and particularly, the number of washing steps is hardly reduced in the washing at ordinary temperature, and the washing steps can be improved by hot water washing, but the water resistance is more excellent than the case of using a sulfate salt such as sodium lauryl sulfate as an emulsifier and ash having a large amount of sulfur (S) and sodium (Na), and particularly, the water resistance is 5 times or more excellent in the case of using the same ash amount. In addition, when a sulfate salt such as sodium lauryl sulfate was used as an emulsifier, it was confirmed that the ash content could be reduced to 0.1 wt% or less and the water resistance could be significantly improved by performing the coagulation reaction of the present invention and performing hot water washing and dehydration.

As is clear from tables 2 to 2, the acrylic rubber bags (A) to (H) of the present invention were excellent in normal physical properties including Banbury workability, water resistance, compression set resistance and strength characteristics and very excellent in injection moldability (examples 1 to 8).

As is clear from table 2-2, regarding the injection moldability, comparative example 2 is Mw/mn=1.3/injection moldability, which is strongly affected by the molecular weight distribution (Mw/Mn) of the acrylic rubber: x, reference example 5 is Mw/mn=1.55/injection moldability: delta, reference example 4 is Mw/mn=1.99/injection moldability: examples 3 to 8 and reference examples 1 to 3 were Mw/Mn2.39 to 2.45/injection moldability: excellent), examples 1 to 2 were Mw/mn=2.91 to 2.94/injection moldability: as shown in the following, mw/Mn is most preferably in the vicinity of 2.4, and the acrylic rubber of the present invention is excellent in injection moldability. It is also found that the molecular weight distribution (Mz/Mw) focusing on the high molecular weight region is sufficiently broad, the number average molecular weight (Mn), the weight average molecular weight (Mw) and the z-average molecular weight (Mz) are sufficiently large, and when the range of Mw/Mn of the present invention is within, the injection moldability can be improved without impairing the strength characteristics (comparison of examples 1 to 8, reference examples 1 to 5 and comparative example 2).

As is clear from tables 2-1 and 2-2, the acrylic rubber packages (A) to (M) having excellent injection moldability without impairing the strength characteristics and having a molecular weight distribution (Mw/Mn) within a specific range can be produced by using specific amounts of an organic radical generator and a chain transfer agent, in particular, n-dodecyl mercaptan as the chain transfer agent (examples 1 to 8 and reference examples 1 to 5). It is also clear from tables 2-1 and 2-2 that injection moldability can be improved without impairing strength characteristics by adding the chain transfer agent (n-dodecyl mercaptan) in batches instead of continuously adding the chain transfer agent (n-dodecyl mercaptan) (reference example 5). This is presumably because, by elongating one polymer chain without adding a chain transfer agent at the initial stage and reducing the organic radical generator, and by adding a chain transfer agent during polymerization, a high molecular weight component and a low molecular weight component can be produced in a well-balanced manner, and the molecular weight distribution (Mw/Mn) is brought into a specific range, whereby the strength characteristics and injection moldability are highly balanced, although no distinct double peaks are formed in the GPC chart. In order to effectively widen the molecular weight distribution (Mw/Mn), the number of times of post-addition in the batch has a large influence, and the number of times is twice as compared with the number of times of post-addition in the batch, which is three times (comparison of reference examples 1 to 3 and reference example 4). In addition, although not shown in tables 2-1 and 2-2, in the examples of the present invention, sodium ascorbate was added as a reducing agent 120 minutes after initiation of polymerization, whereby a high molecular weight component of the acrylic rubber was easily produced, and the effect of widening the molecular weight distribution (Mw/Mn) of the chain transfer agent after addition was enhanced.

It is also clear from tables 2-1 and 2-2 that if the drying of the aqueous pellets is changed from direct drying to a screw type biaxial extrusion dryer, the molecular weight distribution (Mw/Mn) is not changed when operated under normal conditions (comparison of examples 5 to 8 with reference examples 1 to 3), and the molecular weight distribution (Mw/Mn) of the acrylic rubber is widened by setting the drying conditions of the screw type biaxial extrusion dryer to be optimally sheared, the injection moldability of the acrylic rubber can be further improved (comparison of examples 3 to 4 with reference example 4), and the effect of injection moldability is reduced when the molecular weight distribution (Mw/Mn) is too wide (comparison of examples 1 to 2 with examples 5 to 8). Further, although examples and comparative examples of the present invention are not shown, it is understood that if a redox catalyst of an inorganic radical generator is used, the molecular weight distribution (Mw/Mn) of the resulting acrylic rubber is too broad and the injection moldability is poor. This is considered to be because, in the case of the organic radical generator, the polymerization catalyst exists in the micelle of the emulsion polymerization, the polymerization proceeds continuously in the micelle, and in the case of the inorganic radical generator, the polymerization catalyst exists outside the micelle, and the polymerization proceeds outside the micelle, so that these differences in molecular weight distribution occur, and the injection moldability is affected.

As is clear from tables 2 to 2, the acrylic rubber bags (A) to (H) of the present invention are excellent in normal physical properties including Banbury workability, water resistance, compression set resistance and strength characteristics and particularly excellent in storage stability.

As is clear from tables 2 to 2, the specific weights of the acrylic rubber packs (A) to (M) were much larger than those of the pellet-like acrylic rubbers (N) to (O), and the specific weights, that is, the air inclusion amounts, were about the storage stability (comparison of examples 1 to 8, reference examples 1 to 5 and comparative examples 1 to 2). The acrylic rubber bag having a large specific gravity can be obtained by compacting a granulated acrylic rubber with a baler to form a bale (reference examples 1 to 5), and more preferably by extruding the resultant product into a sheet by a screw type biaxial extrusion dryer and laminating the sheet to form a bale (examples 1 to 8). It is also found that the smaller the ash content, the better the storage stability of the acrylic rubber bag (examples 1 to 8 and reference examples 1 to 5). The results of reference example 5 in Table 2-2 were the same except that the specific gravity of the acrylic rubber bag (M) of reference example 5 was reduced to 0.769 when the characteristic value of the pellet-shaped acrylic rubber after direct drying was measured without using a baler. In addition, it is also important for the storage stability of the acrylic rubber bag that the pH is 6 or less.

[ particle size of resulting hydrous pellets ]

The proportion of the aqueous aggregates produced in the coagulation step in examples 1 to 8, reference examples 1 to 5 and comparative examples 1 to 2 to the total amount of the aqueous aggregates produced in the range of (1) 710 μm to 6.7mm (not passing 710 μm and passing 6.7 mm), (2) 710 μm to 4.75mm (not passing 710 μm and passing 4.75 mm), (3) 710 μm to 3.35mm (not passing 710 μm and passing 3.35 mm) was measured using JIS sieves. These results are shown below.

Example 1: (1) 91 wt%, (2) 91 wt%, (3) 84 wt%

Example 2: 96 wt%, (2) 95 wt%, and (3) 89 wt%

Example 3: (1) 91 wt%, (2) 85 wt%, and (3) 79 wt%

Example 4: (1) 93 wt%, (2) 90 wt%, and (3) 84 wt%

Example 5: (1) 95 wt%, (2) 93 wt%, and (3) 90 wt%

Example 6: (1) 89 wt%, (2) 85 wt%, and (3) 79 wt%

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

Reference example 1: (1) 95 wt%, (2) 94 wt%, and (3) 91 wt%

Reference example 2: (1) 89 wt%, (2) 86 wt%, and (3) 83 wt%

Reference example 3: (1) 95 wt%, (2) 94 wt%, and (3) 88 wt%

Reference example 4: (1) 93 wt%, (2) 93 wt%, and (3) 90 wt%

Reference example 5: (1) 93 wt%, (2) 89 wt%, and (3) 78 wt%

Comparative example 1: (1) 17 wt%, (2) 3 wt%, (3) 0 wt%

Comparative example 2: (1) 10 wt%, (2) 2 wt%, (3) 0 wt%

From these results, it was found that even when the same washing was performed with the size of the aqueous aggregates produced in the coagulation step, the ash content remaining in the acrylic rubber bag was different, and although the specific proportions of (1) to (3) were large, the washing efficiency was high, the ash content was reduced, and the water resistance was excellent (comparison between reference examples 1 to 5 and comparative examples 1 to 2 of Table 2). It is also found that the ash removal rate at the time of dehydration is also high in the water-containing pellets having a large specific ratio of (1) to (3), and the ash amount at the time of dehydration (water content) is lower than that at the time of dehydration (water content 30% by weight) in examples 1 to 6, and the water resistance of the acrylic rubber bag is improved.

For reference, the procedure was carried out in the same manner as in comparative example 1 (reference example 7) except that the emulsion polymerization liquid was added to the coagulation liquid in the coagulation step (reference example 6), and the coagulant concentration of the coagulation liquid was changed from 0.7% by weight to 2% by weight, except that the particle size ratios (1) to (3) of the produced aqueous pellets and the ash amount (4) in the acrylic rubber bag were measured in the same manner as in comparative example 1.

Reference example 6: (1) 91 wt%, (2) 57 wt%, (3) 25 wt%, (4) 0.51 wt%

Reference example 7: (1) 92 wt%, (2) 75 wt%, (3) 42 wt%, (4) 0.40 wt%

The mooney scorch storage stability of the acrylic rubber compositions comprising the acrylic rubber packages (a) to (H) of examples 1 to 8 was evaluated according to the following criteria by measuring the mooney scorch time t5 (minutes) at a temperature of 125 ℃ in accordance with JIS K6300 by the method of evaluating the processing stability based on the foregoing mooney scorch inhibition. The results were excellent.

And (3) the following materials: the Mooney scorch time t5 exceeds 3.3 minutes

And (2) the following steps: the Mooney scorch time t5 is 2 to 3.3 minutes

X: the Mooney scorch time t5 is less than 2 minutes

In the acrylic rubber packages (a) to (H), the cooling rate of the sheet-like dry rubber extruded from the screw type biaxial extrusion dryer was substantially as high as about 200 ℃/hr, and was 40 ℃/hr or more, as in example 1.

Further, the deviation of the amount of methyl ethyl ketone insoluble component was evaluated for each rubber sample by the method described above. That is, the deviation of the methyl ethyl ketone insoluble component amount of the rubber sample was evaluated as follows: the amount of methyl ethyl ketone insoluble component at 20 points arbitrarily selected from 20 parts (20 kg) of the rubber sample was measured, and evaluated based on the above criteria.

When the gel amount of the acrylic rubber packs (a) to (H) obtained in examples 1 to 8 and the pellet-like acrylic rubber (O) obtained in comparative example 2 were evaluated for the variability of the gel amounts, the results of the acrylic rubber packs (a) to (H) were all "x", and the result of the pellet-like acrylic rubber (O) was "x".

This is presumably because the acrylic rubber bags (a) to (H) were melt kneaded and dried by a screw type biaxial extruder, and the gel amount of methyl ethyl ketone insoluble components was almost eliminated, and the gel amount deviation was almost eliminated, so that the banbury workability could be significantly improved.

On the other hand, the pellet-like acrylic rubber subjected to emulsion polymerization and coagulation washing under the conditions for producing the pellet-like acrylic rubber (O) of comparative example 2 was put into a screw type biaxial extrusion dryer under the same conditions as in example 1, and extrusion-dried, and the gel amount deviation measured for the obtained acrylic rubber could be reduced to a level substantially equivalent to that of the acrylic rubber bag (a) and the banbury processability could be significantly improved.

[ Release of Metal mold ]

The rubber compositions of the acrylic rubber bags (A) to (H) obtained in examples 1 to 8 were press-fitted

The mold was taken out of the mold, and the mold release properties were evaluated based on the following criteria, wherein the acrylic rubber bags (A) to (H) were excellent.

And (3) the following materials: can be easily released from the metal mold without mold residue

And (2) the following steps: can be easily released from the metal mold, but only slight mold residues are visible

Delta: can be easily released from the metal mold, but has a small amount of mold residue

X: difficult to be peeled from a metal mold

Description of the reference numerals

1. An acrylic rubber manufacturing system;

3. a coagulation device;

4. a cleaning device;

5. a screw extruder;

6. a cooling device;

7. and a glue wrapping device.

Claims

1. An acrylic rubber bag formed of an acrylic rubber having an ion-reactive group,

the gel amount of the methyl ethyl ketone insoluble component in the acrylic rubber bag is 15 wt% or less, the gel amount of the methyl ethyl ketone insoluble component at 20 is arbitrarily measured to be all within the range of (average value.+ -. 5 wt%),

the pH of the acrylic rubber bag is below 6, the ash content is above 0.0005 wt% and below 0.2 wt%, and the total amount of sodium, sulfur, calcium, magnesium and phosphorus in ash is above 90 wt%.

2. The acrylic rubber bag according to claim 1, wherein the ion-reactive group is at least one reactive group selected from the group consisting of a carboxyl group, an epoxy group, and a chlorine atom.

3. The acrylic rubber bag according to claim 1 or 2, wherein the specific gravity of the acrylic rubber bag is 0.8 or more.

4. The acrylic rubber bag according to any one of claims 1 to 3, wherein a ratio (Mw/Mn) of a weight average molecular weight (Mw) to a number average molecular weight (Mn) of the acrylic rubber is in a range of 1 to 25.

5. The acrylic rubber bag according to any one of claims 1 to 4, wherein a ratio (Mw/Mn) of a weight average molecular weight (Mw) to a number average molecular weight (Mn) of the acrylic rubber is in a range of 1.5 to 3.

6. The acrylic rubber bag according to any one of claims 1 to 5, wherein the number average molecular weight (Mn) of the acrylic rubber is in the range of 1 to 300 ten thousand.

7. The acrylic rubber bag according to any one of claims 1 to 6, wherein the number average molecular weight (Mn) of the acrylic rubber is in the range of 30 to 150 tens of thousands.

8. The acrylic rubber bag according to any one of claims 1 to 7, wherein the GPC measurement solvent of the weight average molecular weight (Mw) or the number average molecular weight (Mn) of the acrylic rubber is a dimethylformamide-based solvent.

9. The acrylic rubber bag according to any one of claims 1 to 8, wherein a gel amount of methyl ethyl ketone insoluble component of the acrylic rubber bag is 5% by weight or less.

10. The acrylic rubber bag according to any one of claims 1 to 9, wherein a ratio of complex viscosity at 100 ℃ ([ η ]100 ℃) to complex viscosity at 60 ℃ ([ η ]60 ℃) ([ η ]100 ℃/[ η ]60 ℃)) is 0.7 or more.

11. The acrylic rubber bag according to any one of claims 1 to 10, wherein the acrylic rubber bag has a water content of less than 1 wt%.

12. The acrylic rubber bag according to any one of claims 1 to 11, wherein the acrylic rubber bag is emulsion-polymerized using a phosphate salt or a sulfate salt as an emulsifier.

13. The acrylic rubber bag according to any one of claims 1 to 12, wherein the acrylic rubber bag is obtained by solidifying and drying a polymerization liquid subjected to emulsion polymerization using an alkali metal salt or a group 2 metal salt of the periodic table as a coagulant.

14. The acrylic rubber bag according to any one of claims 1 to 13, wherein the acrylic rubber bag is melt-kneaded and dried after solidification.

15. The acrylic rubber bag according to claim 14, wherein the melt-kneading and drying are performed in a state substantially free of moisture.

16. The acrylic rubber bag according to claim 14 or 15, wherein the melt-kneading and drying are performed under reduced pressure.

17. The acrylic rubber bag according to any one of claims 14 to 16, wherein the acrylic rubber bag is cooled at a cooling rate of 40 ℃/hr or more after the melt-kneading and drying.

18. The acrylic rubber bag according to any one of claims 1 to 17, wherein the acrylic rubber bag is obtained by washing, dehydrating and drying an aqueous pellet having a particle diameter in the range of 710 μm to 6.7mm in a proportion of 50% by weight or more.

19. The manufacturing method of the acrylic rubber bag comprises the following steps:

a cleaning step of cleaning the produced water-containing pellets;

a dehydration, drying and molding step of dehydrating the washed aqueous pellets to a water content of 1 to 40 wt% by using a dehydration cylinder having a dehydration slit, a drying cylinder under reduced pressure, and a screw type biaxial extrusion dryer having a die at the tip, and then drying the dehydrated pellets to less than 1 wt% by using the drying cylinder, and extruding a sheet-like dry rubber from the die;

a cooling step of cooling the extruded sheet-like dry rubber;

a cutting step of cutting the cooled sheet-like dry rubber; and

and a lamination step of laminating the cut sheet-like dry rubber.

20. The method for producing an acrylic rubber bag according to claim 19, wherein the acrylic rubber bag according to any one of claims 1 to 18 is produced.

21. The method for producing an acrylic rubber bag according to claim 19 or 20, wherein in the emulsion polymerization step, a chain transfer agent is added after the batch during the emulsion polymerization to continue the polymerization.

22. The method for producing an acrylic rubber bag according to any one of claims 19 to 21, wherein the contacting of the emulsion polymerization liquid with the coagulant in the coagulation step is to add the emulsion polymerization liquid to the stirred coagulant.

23. The method for producing an acrylic rubber bag according to any one of claims 19 to 22, wherein in the emulsion polymerization step, emulsion polymerization is performed using a phosphate salt or a sulfate salt as an emulsifier.

24. The method for producing an acrylic rubber bag according to any one of claims 19 to 23, wherein the polymerization liquid produced in the emulsion polymerization step is coagulated by contacting with a coagulant comprising an alkali metal salt or a group 2 metal salt of the periodic table.

25. The method for producing an acrylic rubber bag according to any one of claims 19 to 24, wherein the polymerization liquid produced in the emulsion polymerization step is solidified by contacting with a coagulant, and then melt-kneaded and dried.

26. The method for producing an acrylic rubber bag according to claim 25, wherein the melt kneading and drying are performed in a state substantially free of moisture.

27. The method for producing an acrylic rubber bag according to claim 25 or 26, wherein the melt-kneading and drying are performed under reduced pressure.

28. The method for producing an acrylic rubber bag according to any one of claims 19 to 27, wherein a maximum torque of the screw type biaxial extrusion dryer at the time of melt kneading and drying is in a range of 5 to 125 n.m.

29. The method for producing an acrylic rubber bag according to any one of claims 19 to 28, wherein the acrylic rubber after melt-kneading and drying is cooled at a cooling rate of 40 ℃/hr or more.

30. The method for producing an acrylic rubber bag according to any one of claims 19 to 29, wherein the aqueous pellet having a particle diameter in the range of 710 μm to 6.7mm in a proportion of 50% by weight or more is washed, dehydrated and dried.

31. The method for producing an acrylic rubber bag according to any one of claims 19 to 30, wherein the cutting temperature of the sheet-like dry rubber in the cutting step is 60 ℃ or lower.

32. The method for producing an acrylic rubber bag according to any one of claims 19 to 31, wherein the lamination temperature of the sheet-like dry rubber in the cooling step is 30 ℃ or higher.

33. A rubber composition comprising a rubber component comprising the acrylic rubber bag according to any one of claims 1 to 18, a filler and a crosslinking agent.

34. The rubber composition according to claim 33, wherein the filler is a reinforcing filler.

35. The rubber composition according to claim 33, wherein the filler is a carbon black.

36. The rubber composition according to claim 33, wherein the filler is a silica type.

37. The rubber composition according to any one of claims 33 to 36, wherein the crosslinking agent is an organic crosslinking agent.

38. The rubber composition according to any one of claims 33 to 37, wherein the crosslinking agent is a multi-component compound.

39. The rubber composition according to any one of claims 33 to 38, wherein the crosslinking agent is an ion-crosslinkable compound.

40. The rubber composition according to claim 39, wherein the crosslinking agent is an ion-crosslinkable organic compound.

41. The rubber composition of claim 39 or 40, wherein the crosslinking agent is a polyionic organic compound.

42. The rubber composition according to any one of claims 39 to 41, wherein the ion of the ion-crosslinkable compound, the ion-crosslinkable organic compound or the polyion-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.

43. The rubber composition according to claim 41, wherein the crosslinking agent is at least one polyionic compound selected from the group consisting of a polyamine compound, a polyepoxide compound, a polycarboxylic acid compound and a polythiol compound.

44. The rubber composition according to any one of claims 33 to 43, wherein the content of the crosslinking agent is in the range of 0.001 to 20 parts by weight relative to 100 parts by weight of the rubber component.

45. The rubber composition of any of claims 33-44, wherein the rubber composition further comprises an anti-aging agent.

46. The rubber composition according to claim 45, wherein the antioxidant is an amine-based antioxidant.

47. A process for producing a rubber composition comprising mixing the rubber component comprising the acrylic rubber bag according to any one of claims 1 to 18, a filler and an optionally used antioxidant, and then mixing a crosslinking agent.

48. A rubber crosslinked product obtained by crosslinking the rubber composition according to any one of claims 33 to 46.

49. A rubber crosslinked according to claim 48 wherein the crosslinking of the rubber composition is performed after molding.

50. A rubber crosslinked according to claim 48 or 49 wherein the crosslinking of the rubber composition is a crosslinking that proceeds in both primary and secondary crosslinking.