JP3009379B2 - Acrylic polymer coagulated product and molded product thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molded article having excellent impact resistance comprising a multi-layer polymer of an acrylic polymer coagulated product, an acrylic polymer coagulated product for obtaining the same, and an acrylic polymer composition. And a method for producing a coagulated acrylic polymer.

[0002]

2. Description of the Related Art As a method for improving the impact resistance of a synthetic resin such as an acrylic resin, a styrene resin, and a vinyl chloride resin,
Generally, a rubber phase having elasticity is discontinuously dispersed in a hard resin. The introduction of diene rubber is the most common, but acrylic rubber is also widely used from the viewpoint of weather resistance.

[0003] Modified resins using acrylic rubber include:
Various multi-layered polymers based on a core and shell structure and combining a soft layer and a hard layer have been studied (Japanese Patent Publication No. 54-182).
No. 98, Japanese Patent Publication No. 55-27576, Japanese Patent Publication No. 62-41241, etc.). An emulsion polymerization method is widely used as a production method thereof. In the method for producing a polymer using these emulsion polymerization methods, a step of separating the polymer from the polymer latex is required. As this method, aluminum chloride,
A method of adding an inorganic salt such as magnesium sulfate, a method of adding an acid such as sulfuric acid, a spray drying method, and the like have been adopted. However, the above-mentioned method has a problem that the obtained polymer is in the form of a fine powder and is difficult to handle, which causes a decrease in productivity and a decrease in molding workability. On the other hand, those molded using these polymers also had problems such as inferior optical properties due to heating and coloring, easy whitening when immersed in hot water, and poor hot water resistance.

[0004] As a method of improving the handleability of a polymer, a method of suppressing a blocking phenomenon at the time of drying by mixing a slurry of an impact resistance modified polymer and a slurry of a hard inelastic polymer and then drying the mixture ( JP-A-58-1742) has been proposed. Although some improvement effect is recognized, it is not sufficiently satisfactory, and coloring and hot water resistance are not improved.

As a method for improving coloring, -OS
Polymerization is carried out using an emulsifier having a group represented by O ₃ M-, -COOM, and -SO ₃ M (where M is K or Na), and the obtained latex is contacted with an aqueous solution of magnesium sulfate to form a polymer. method of separating (JP 61-108629 _{JP), - PO 3 M 2,} -PO 2 M ( where M is an alkali metal or alkaline earth metal) polymerization was conducted by using an emulsifier having a group represented by A method of contacting the obtained latex with an aqueous solution of magnesium sulfate to separate a polymer (JP-A-63-227606) has been proposed. Although some improvement effect is recognized, it is not satisfactory, and the separated polymer has a disadvantage that it is difficult to handle in a fine powder form, and the hot water resistance is not improved.

[0006]

That is, an object of the present invention is to provide a molded article of an acrylic polymer coagulated material having excellent impact resistance, optical properties and hot water resistance, and an acrylic polymer coagulated material for obtaining the same. And a composition thereof, and a production method thereof.

[0007]

Means for Solving the Problems The present inventors have conducted intensive studies in view of the above situation, and as a result, have been characterized in that they are multi-layered polymers obtained by an emulsion polymerization method and are freeze-coagulated. The present inventors have found that the above problems can be solved by the acrylic polymer solidified product described above, and have completed the present invention.

That is, the present invention relates to a multi-layered polymer obtained by an emulsion polymerization method, wherein the outermost layer of the multi-layered polymer comprises (1) at least one methacrylic acid ester unit of 40 to 100% by weight, A layer comprising 0 to 60% by weight of other monomer units copolymerizable therewith and having a glass transition temperature (hereinafter referred to as T
g), and at least one of the inner layers comprises (2) 40 to 99.9% by weight of at least one acrylate ester unit and 0 to 9 other monomer units copolymerizable therewith. 60% by weight, polyfunctional monomer unit 0.1
A soft layer having a Tg of less than 25 ° C. when the layer alone is polymerized, and a latex of the multilayer structure polymer is freeze-coagulated at a speed of 4 cm / hr or less. The present invention relates to a coagulated acrylic polymer, a molded product thereof, and a method for producing the same.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The multi-layered polymer constituting the coagulated acrylic polymer (hereinafter sometimes simply referred to as coagulated material) of the present invention is obtained by an emulsion polymerization method. The outer layer is (1) a layer composed of 40 to 100% by weight of at least one type of methacrylate unit and 0 to 60% by weight of another monomer unit copolymerizable therewith, and when the layer is polymerized alone. A hard layer having a Tg of 25 ° C. or more, wherein at least one of the inner layers comprises (2) 40 to 99.9% by weight of at least one acrylate unit, and another monomer copolymerizable therewith. A layer comprising 0 to 60% by weight of a unit and 0.1 to 5% by weight of a polyfunctional monomer unit, and is composed of a soft layer having a Tg of less than 25 ° C when polymerized by the layer alone. The proportion of the outermost layer in the multilayer polymer is not particularly limited, but is preferably from 10 to 80% by weight in order to obtain good dispersibility during melt-kneading.
g is preferably 50 ° C. or higher in order to obtain good heat resistance of the molded product. Further, the molecular weight of the outermost layer is preferably adjusted. The reason is that when the coagulated product of the present invention is formed or processed, or when the coagulated product of the present invention is used as a modifier for a synthetic resin, heat-melt fluidity is necessary. This is important from the viewpoint of compatibility. This adjustment can be performed using a chain transfer agent such as mercaptan. 25 ° C. in the multilayer polymer
The proportion of the soft layer having a Tg of less than 10% is also not particularly limited, but is preferably 10 to 80% by weight in order to exhibit impact resistance, and Tg is preferably 0 ° C or lower from the same point. Further, the inner layer of the multi-layered polymer may be composed of only the soft layer or at least one kind of the methacrylate unit 40 to 40.
100% by weight, other monomer units copolymerizable therewith 0
A layer composed of 0 to 60% by weight and a polyfunctional monomer unit of 0 to 5% by weight.
Any layer structure consisting of a hard layer having g can be adopted. For example, in a polymer having a multilayer structure including the outermost layer, a two-layer structure of a soft layer-a hard layer, a three-layer structure of a hard layer-a soft layer-a hard layer, a soft layer-a hard layer-a soft layer-a hard layer from the innermost layer And a four-layer structure of hard layer-soft layer-soft layer-hard layer.

As the monomer units constituting the hard layer of the multilayer polymer, the following units are used. Examples of the methacrylate include methyl methacrylate, ethyl methacrylate, butyl methacrylate, benzyl methacrylate, cyclohexyl methacrylate, and the like. These may be used alone or in combination, but methyl methacrylate is preferred. Other copolymerizable monomers include acrylates such as methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, cyclohexyl acrylate, benzyl acrylate, styrene, vinyl toluene, α- Aromatic vinyl compounds such as methylstyrene, N-cyclohexylmaleimide, No-chlorophenylmaleimide, N-tert-
Examples thereof include N-substituted maleimide compounds such as butylmaleimide and vinyl cyanide compounds such as acrylonitrile and methacrylonitrile, which are used alone or in combination. Also, as the polyfunctional monomer, allyl methacrylate, allyl acrylate, triallyl cyanurate, allyl cinnamate, allyl sorbate, diallyl maleate, diallyl phthalate, triallyl trimellitate, diallyl fumarate, diallyl fumarate, ethylene glycol diallyl (Meth) acrylate,
Examples include polyfunctional monomers such as polyethylene glycol di (meth) acrylate, divinylbenzene, and 1,3-butylene glycol di (meth) acrylate, which are used alone or in combination.

The following units are used as monomer units constituting the soft layer of the multilayer polymer. Examples of the acrylate include methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, cyclohexyl acrylate, benzyl acrylate, and the like.These may be used alone or in combination, but preferably acrylic Butyl acid, acrylic acid-2
-Ethylhexyl. Other copolymerizable monomers include diene compounds such as 1,3-butadiene, 2,3-dimethylbutadiene and isoprene, aromatic vinyl compounds such as styrene, vinyltoluene and α-methylstyrene, and methyl methacrylate. And methacrylic acid esters such as ethyl methacrylate, butyl methacrylate, benzyl methacrylate, and cyclohexyl methacrylate; and vinyl cyanide compounds such as acrylonitrile and methacrylonitrile. These may be used alone or in combination. Further, as the polyfunctional monomer, allyl methacrylate, allyl acrylate, triallyl cyanurate, allyl cinnamate, allyl sorbate, diallyl maleate, diallyl phthalate,
Triallyl trimellitate, diallyl fumarate, ethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, divinylbenzene,
Examples thereof include polyfunctional monomers such as 1,3-butylene glycol di (meth) acrylate, which are used alone or in combination.

The particles of the multi-layered polymer obtained by the emulsion polymerization method are not particularly limited, but may vary in the particle size range of 0.01 to 0.5 μm. The thickness is preferably 0.05 to 0.3 µ for the purpose of exhibiting impact resistance.

The most characteristic feature of the coagulated acrylic polymer of the present invention is that it is a frozen coagulated material having excellent properties. On the other hand, those coagulated by the spray drying method or the acid or salt addition method cannot be used in the present invention because the handling properties such as drying are poor and the extrusion stability during extrusion molding is poor.

In the present invention, latex, freeze coagulation,
The coagulate is defined as follows. The latex is obtained by emulsion polymerization, and is obtained by dispersing spherical polymer particles having a diameter of about 0.01 to 0.5 μm whose surface is protected by a surfactant or the like in water. Freezing and coagulation is the process of freezing the latex obtained by the emulsion polymerization method, aggregating the particles of the multilayer structure polymer, coagulating by pressing, breaking the emulsified state, and separating the polymer from the latex. It is. With the coagulated product, the spherical particles of the multilayer structure polymer obtained by the emulsion polymerization method are aggregated by freezing the latex, pressed, frozen, melted, dehydrated and separated from the latex by more than tens of μ to several thousand μ. Refers to a solid having a particle size of

Although the coagulated product of the present invention can have various particle sizes as described above, the average particle size is preferably from 20 to 2000 μ, more preferably from 50 to 1000 μ. If it is less than 20 μ, the separability during filtration will be poor, and if it exceeds 2000 μ, the dispersibility during melt-kneading tends to be poor. The average particle size of the coagulated product is 20 to 20
When the size is 00 μ, the handling property is remarkably improved.

The multi-layered polymer constituting the coagulated product of the present invention is produced by a known emulsion polymerization method. As a method for producing a multilayer polymer, first, a desired monomer mixture is emulsion-polymerized to form core particles, and then the other monomer mixture is emulsion-polymerized in the presence of the core particles to form a shell around the core particles. Create Then, another monomer mixture is emulsion-polymerized in the presence of the core and shell particles to form another shell.
By repeating such a reaction, a desired multilayer polymer is obtained.

The type and amount of the emulsifier used in the emulsion polymerization are selected depending on the stability of the polymerization system, the intended particle size, and the like.
Known emulsifiers such as nonionic surfactants can be used alone or in combination. Particularly, an anionic surfactant is preferably used. Examples of the anionic surfactant include carboxylate salts such as sodium stearate, sodium myristate and sodium N-lauroyl sarcosinate, sulfonates such as sodium dioctylsulfosuccinate and sodium dodecylbenzenesulfonate, and sulfates such as sodium lauryl sulfate. Examples thereof include ester salts and phosphate salts such as sodium mono-n-butylphenylpentaoxyethylene phosphate.

The polymerization initiator used in the emulsion polymerization is not particularly limited, but inorganic peroxides such as potassium persulfate and ammonium persulfate, hydrogen peroxide-ferrous salt, potassium persulfate-sodium acid sulfite are used. Water-soluble and oil-soluble redox initiators, such as ammonium persulfate-sodium acid sulfite, water-soluble redox initiators such as cumene hydroperoxide-sodium formaldehyde sulfoxylate, and tert-butyl hydroperoxide-sodium formaldehyde sulfoxylate. Is used.

The chain transfer agent optionally used includes n-dodecyl mercaptan, n-lauryl mercaptan, tert-dodecyl mercaptan, sec-butyl mercaptan and the like. In emulsion polymerization,
The monomer, emulsifier, initiator, chain transfer agent and the like may be added by any known method such as a batch addition method, a split addition method, and a continuous addition method.

The freezing and coagulation in the present invention is considered to proceed by the following mechanism. When the latex is cooled below the freezing point of water, ice crystals are generated in the aqueous phase, and the latex grows while excluding the spherical polymer particles and the water-soluble substance dissolved in the aqueous phase. The spherical polymer particles are trapped between the ice crystals, and the water-soluble substances are also concentrated there and precipitate when the concentration reaches a saturation value. As the ice crystals grow, the spherical polymer particles are gradually pressed. As the temperature further decreases, the concentrated aqueous solution of the water-soluble substance freezes. As the freezing proceeds, the bare spherical polymer particles are compressed and firmly pressed. When the latex that has undergone this step is melted, the compression of the spherical polymer particles is not broken and is separated from the aqueous phase as a coagulated product.

However, the properties of the coagulated product and the molded product obtained therefrom are considerably different depending on the type of the polymer and the freezing conditions, and those having excellent properties such as handleability, impact resistance, optical properties, hot water resistance, etc. It is not always obtained by the freeze-coagulation method. By combining a specific multilayer structure polymer and a freeze-coagulation method, preferably a specific freezing condition, a suitable pressure-bonding property of the spherical polymer particles, a suitable particle size of the coagulated material, and an easy washing of impurities such as an emulsifier. And the object of the present invention is achieved for the first time.

In the production of the coagulated product of the present invention, as a freezing method, a known air freezing method, contact freezing method, immersion freezing method, spray freezing method or the like is used. hr or less, preferably 0.7-4
It is necessary to freeze at a rate of cm / hr. When frozen at a speed exceeding 4 cm / hr, handleability and extrusion stability in the subsequent process become poor. In the present invention, when the polymer latex temperature reaches 0 ° C., the freezing is started, and when the polymer latex temperature reaches −5 ° C., the freezing is terminated. The thickness at which the polymer latex is frozen is defined as the freezing speed. Thaw after freezing is 40
C. to 100 ° C., and the obtained polymer is cooled to 0 ° C. to 100 ° C.
It is preferable to wash with water or warm water.

In the present invention, the above coagulated product and a methacrylic polymer comprising 50 to 100% by weight of a methyl methacrylate unit and 0 to 50% by weight of another monomer unit copolymerizable therewith are constituted. Acrylic polymer composition to be
It is preferably used. It is preferable that the blending ratio of the acrylic polymer coagulated product and the methacrylic polymer in the acrylic polymer composition is 1 to 99% by weight for the former and 99 to 1% by weight for the latter. In order to obtain properties balanced with impact resistance, optical properties, weather resistance, heat resistance, etc.,
5 to 70% by weight of coagulated material, 30 to 30% of methacrylic polymer
More preferably, it is 95% by weight. Further, the acrylic polymer composition of the present invention, an acrylic polymer coagulation composition obtained by emulsion polymerization of a methacrylic polymer and emulsion blending with the multilayer structure polymer, the object of the present invention. Can be added as needed within a range that does not hinder the addition.

In the methacrylic polymer, other copolymerizable monomer units include ethyl methacrylate and
Methacrylates such as cyclohexyl methacrylate and benzyl methacrylate, acrylates such as methyl acrylate and ethyl acrylate, styrene, vinyltoluene, and aromatic vinyl compounds such as α-methylstyrene;
N-substituted maleimide compounds such as N-cyclohexylmaleimide, No-chlorophenylmaleimide, N-tert-butylmaleimide, and vinyl cyanide compounds such as acrylonitrile and methacrylonitrile, which are used alone or in combination . The molecular weight of the homopolymer or copolymer is preferably adjusted in order to improve moldability, and this adjustment can be performed using a chain transfer agent such as mercaptan. This methacrylic polymer can be obtained by known suspension polymerization, solution polymerization, emulsion polymerization, bulk polymerization, or the like.

Conventionally, when the impact resistance of an acrylic resin or the like is improved by a composition in which an elastic rubber phase is blended, there has been a disadvantage that various properties inherent in the base resin are significantly reduced. According to the acrylic polymer composition of the present invention, the impact resistance of the acrylic resin can be improved without significantly lowering various properties such as optical properties, hot water resistance, and weather resistance inherent in the acrylic resin. Therefore, the range of use is expanded.

In the acrylic polymer composition of the present invention, the method of blending is not particularly limited, but after mixing with a Henschel mixer or the like, 200 to 300 using an extruder.
It can be produced by a known method such as melting and kneading at a temperature of ℃.

In the present invention, the above-mentioned coagulated acrylic polymer and acrylic polymer composition can be used for modifying synthetic resins such as vinyl chloride resins and styrene resins. In that case, the impact resistance of the base resin can be improved without significantly lowering various properties such as the optical properties inherent to the base resin. At this time, for example, 1 to 80% by weight of the acrylic polymer coagulate, 50 to 100% by weight of at least one of a styrene unit, a vinyl chloride unit and an acrylonitrile unit, and 0 to 100% of other monomer units copolymerizable therewith. A composition comprising from 50 to 50% by weight of a homopolymer or from 20 to 99% by weight is effective. In the latter homo- or copolymer, other copolymerizable monomer units may be the same as those used in the acrylic polymer composition, and the homo- or copolymer is known. Obtained by suspension polymerization, solution polymerization, emulsion polymerization, bulk polymerization, and the like.

[0028] The present invention also relates to a molded article which is formed by heating alone or a mixture of the above-mentioned coagulated product and the above-mentioned polymer composition.

The molded product in the present invention is a molding material, a sheet, a film, and the like, and further includes an injection-molded article, and a thermally processed product of the sheet and the film.

The molded product of the present invention comprises the above-mentioned coagulated product or the above-mentioned polymer composition alone or as a mixture, and preferably has a yellow index (YI) satisfying the following formula. YI ≦ 0.035X + 2.0 [where X is the ratio (% by weight) of the multilayer polymer in the molded product. ]

In the present invention, a molded article having excellent impact resistance, optical properties, and hot water resistance can be obtained by using the above-mentioned coagulated product and satisfying the conditions of YI. With conventional molded products, it is difficult to obtain excellent molded products that simultaneously satisfy impact resistance, optical properties, and hot water resistance. Further, even in a molded product using the above-mentioned material, if the yellow index does not satisfy the above formula, the increase in coloring due to the molding process is large, and the use range may be limited. The yellow index indicates that the molded product with a thickness of 3 mm is ASTM-D
It is a value measured by the method shown in 1925. The molded product in the present invention is produced by a known method such as injection molding, extrusion molding, press molding, vacuum molding and the like. Currently, commercially available molding materials are used to add a dye to make a complementary color or to add a stabilizer to suppress yellow coloring, but according to the present invention, such additives are used. No special addition is required. Further, the improvement of the hot water resistance broadens the range of use for bathroom articles and the like, and further improves the weather resistance.

The coagulated acrylic polymer, the acrylic polymer composition and the molded product of the present invention may contain a lubricant, an ultraviolet absorber, a light stabilizer, a heat stabilizer and the like, if necessary, as long as the object of the present invention is not hindered. Stabilizers, antioxidants, plasticizers, dyes and pigments, antistatic agents, flame retardants, other resins and the like can also be added.

[0033]

The present invention will be described in more detail with reference to the following examples. The measurement of various characteristics shown in the examples was performed according to the following methods.

(1) Cohesion, polymer composition or solid when dried, fusion and blocking; coagulation, polymer composition or solid is dried at 80 ° C. in a tray hot air dryer at 10 ° C. After drying for a time, check whether fusion or blocking occurs.
The following table shows the results. X: Fusing and blocking occurred. …: No fusion or blocking occurred.

(2) Method for measuring the average particle size of the coagulated product, polymer composition or solid; measuring the particle size of 200 or more coagulated product, polymer composition or solid using a microscope,
The number average particle size was determined.

(3) Evaluation of extrusion stability: A coagulated product, a polymer composition or a solid product was mixed with acrylic resin beads (beads for Parapet EH: manufactured by Kuraray Co., Ltd.) at a ratio of 1: 1 and a mixture of 50φ was prepared. Cylinder temperature 25 using sheet extruder
Extrusion stability at the time of obtaining a sheet having a thickness of 3 mm by melt-kneading at 0 ° C. was examined. Good: A good sheet was obtained without causing surging. Unstable ... Surging was likely to occur, and it was difficult to obtain a good sheet.

(4) Izod impact strength; ASTM-D256 (5) Evaluation of hot water resistance;
It was immersed in hot water of 2 ° C. for 2 hours, the haze value was measured by ASTM-D1003, and the change in haze value (Δhaze) was measured. (6) Total light transmittance; ASTM-D1003 (3 mm plate thickness) (7) Yellow index; ASTM-D1925 (3 mm plate thickness)

(8) Filterability: 11 cm diameter TOYO ROSHI C
Using No. 2 filter paper manufactured by O. Co., Ltd., 500 ml of the freeze-thawed liquid containing 29% by weight of solids was filtered under reduced pressure of 20 mmHg, and the filterability was evaluated by the time required for filtration. △: Filtration time of 5 minutes or more ○: Filtration time of less than 5 minutes

The abbreviations used in Examples, Comparative Examples, Reference Examples, and Reference Comparative Examples are shown below. Methyl methacrylate (MMA), methyl acrylate (MA), ethyl acrylate (EA), butyl acrylate (BA), styrene (ST), allyl methacrylate (ALMA), N-cyclohexylmaleimide (CHMI), 1, 3-butylene glycol dimethacrylate (BGDMA), cumene hydroperoxide (CHP), n-octyl mercaptan (n-OM), sodium formaldehyde sulfoxylate (Rongalit), sodium stearate (SS), sodium dioctyl sulfosuccinate (SD
OSS), sodium lauroyl sarcosinate (LS)
S) indicates parts by weight, and% indicates weight%.

Example 1 In a reaction vessel equipped with a reflux condenser, 250 parts of ion-exchanged water, SS
1.0 parts, MMA 29.4 parts, MA 0.6 parts, ALMA
0.15 parts were charged. Then, 0.3 part of a 10% aqueous potassium persulfate solution was added, the temperature was raised to 80 ° C., and the temperature was maintained for 60 minutes. Then, in the presence of this latex, 0.5 part of a 10% aqueous potassium persulfate solution was added, and 40.7 parts of BA, ST
A monomer mixture consisting of 9.3 parts and 0.25 parts of ALMA was continuously added over 60 minutes and kept for 30 minutes after completion of the addition. Then, in the presence of this latex, 0.2 part of a 10% aqueous potassium persulfate solution was added, and 19.6 parts of MMA was added.
A monomer mixture consisting of 0.4 parts of MA and 0.06 parts of n-OM was continuously added over 30 minutes, and after the addition was completed, the mixture was maintained for 60 minutes to obtain a three-layer polymer latex.

The obtained latex was placed in a stainless steel container so as to have a height of 6 cm, and was frozen in a freezer at a temperature of -20 ° C. As a result of measuring the temperature by placing a thermocouple in the latex, it took 6 hours to reach -5 ° C after reaching 0 ° C. That is, the freezing speed was 1 cm / hr. After the temperature passed -5 ° C, the mixture was cooled for an additional 2 hours to remove the frozen latex.

After the frozen latex was thawed at a temperature of 70 ° C., the polymer was separated by filtration. Further, after repeating washing and dehydration three times with 70 ° C warm water, 80 ° C-1
Dried for 0 hours. Fusing and blocking did not occur, and a smooth coagulated product was obtained, and the average particle size was 200 μm.

The obtained dried coagulated product and acrylic resin beads (parapet EH beads: manufactured by Kuraray Co., Ltd.)
The mixture was mixed at a ratio of one to one, and melt-kneaded at a cylinder temperature of 250 ° C. using a 50φ sheet extruder to obtain a sheet having a thickness of 3 mm. At this time, good extrusion stability was exhibited without causing surging. Table 1 shows the results.

COMPARATIVE EXAMPLE 1 The final latex obtained in Example 1 was subjected to salting out and aggregation at a temperature of 70 ° C. using twice the amount of a 1% aqueous solution of aluminum chloride. Then, washing and dehydration were repeated three times with hot water at 70 ° C., and then dried at 80 ° C. for 10 hours. Since the polymer was fused and blocked, the conditions were changed to 60 ° C. for 15 hours and dried. The average particle diameter of the obtained solid is 20 μm.
Met.

The obtained dried solid matter and acrylic resin beads (parapet EH beads: manufactured by Kuraray Co., Ltd.)
The mixture was mixed at a ratio of one to one, and melt-kneaded at a cylinder temperature of 250 ° C. using a 50φ sheet extruder to obtain a sheet having a thickness of 3 mm. At this time, surging was apt to occur, and it was difficult to obtain a good sheet. Table 1 shows the results.

Comparative Examples 2 to 4 Comparative Example 1 was conducted except that a 33% aqueous sodium chloride solution, a 2% aqueous magnesium sulfate solution and a 1% aqueous sulfuric acid solution were used.
Table 1 shows the results of the evaluation in the same manner as described above.

Comparative Example 5 The final latex obtained in Example 1 was subjected to a hot air temperature of 170
The polymer was dried and separated by spraying into a spray drier at a temperature of 0 ° C.
The obtained solid was in the form of fine powder. The obtained dried solid matter and acrylic resin beads (beads for Parapet EH: manufactured by Kuraray Co., Ltd.) were mixed at a ratio of 1: 1 to 50φ.
Was melted and kneaded at a cylinder temperature of 250 ° C. using a sheet extruder to obtain a sheet having a thickness of 3 mm. At this time, surging was apt to occur, and it was difficult to obtain a good sheet. Table 1 shows the results.

[0048]

[Table 1]

As is evident from Table 1, the frozen coagulated material shows good handleability and extrusion stability.

Examples 2 to 4 The final latex obtained in Example 1 was freeze-coagulated under different freezing conditions. 70 of the frozen latex
After melting at a temperature of ℃, the polymer was separated by filtration,
The filterability was examined. These filtrates were placed in a glass cell having a thickness of 1 cm, and the light transmittance of light having a wavelength of 600 nm was measured. Table 2 shows the results of the evaluation performed by operating in the same manner as in Example 1 except for the above.

[0051]

[Table 2]

Example 5 The dried coagulated product obtained in Example 1 and methacrylic resin (beads for Parapet HR-L: manufactured by Kuraray Co., Ltd.) were mixed with 1
The mixture was mixed at a ratio of 1: 1 and melt-kneaded at a cylinder temperature of 250 ° C. using an extruder of 40φ to obtain pellets. The pellets were subjected to injection molding at a cylinder temperature of 250 ° C. and a mold temperature of 50 ° C. to obtain an Izod impact strength test piece based on ASTM standards and a 50 × 50 × 3 mm flat plate. Table 3 shows the results of evaluating various characteristics using this test piece.

Comparative Examples 6 to 10 Table 3 shows the results of the evaluation performed in the same manner as in Example 5 except that the dried solids obtained in Comparative Examples 1 to 5 were used.

[0054]

[Table 3]

As is clear from Table 3, it is understood that the resin composition comprising the coagulated product by freezing has excellent optical properties, hot water resistance, and good impact resistance as compared with the others.

Example 6 The dried coagulated material obtained in Example 1 was press-formed at 190 ° C. under a pressure of 100 kg / cm ² for 10 minutes using a flat plate press to obtain a flat plate having a thickness of 3 mm. The yellow index and total light transmittance were measured. Yellow index:
3.5, total light transmittance: 90%, which is shown in Table 4.

Comparative Examples 11 to 14 Table 4 shows the results of evaluation by operating in the same manner as in Example 6, except that the dried solids obtained in Comparative Examples 1, 2, 4, and 5 were used.

[0058]

[Table 4]

As is evident from Table 4, it can be seen that the molded product made of the solidified product by freezing is remarkably excellent in optical characteristics as compared with the others.

Examples 7 and 8 and Comparative Examples 15 and 16 Coagulation was carried out in the same manner as in Example 1 and Comparative Example 1, except that the composition of the multilayer polymer and the type and amount of the emulsifier were changed as shown in Table 5. And solids were obtained, and evaluated in the same manner as in Example 1 and Comparative Example 1. The results are shown in Table 6. In Table 5, a horizontal line (-) is used to separate monomer units and the like forming the same layer of the multilayer polymer, and a diagonal line (/) is used when the layers are different. Layer is the innermost layer, and the layer shown on the far right is the outermost layer.

[0061]

[Table 5]

[0062]

[Table 6]

Example 9 and Comparative Example 17 Each of the coagulated product obtained in Example 7 and the solid product obtained in Comparative Example 15 and a methacrylic resin (bead for PARAPET HR-L: manufactured by Kuraray Co., Ltd.) Was operated in the same manner as in Example 2 except that was mixed at a ratio of 7: 3. Table 3 shows the results.

Example 10 and Comparative Example 18 Each of the solidified product obtained in Example 8 and the solid obtained in Comparative Example 16 and a methacrylic resin (bead for Parapet HR-L: manufactured by Kuraray Co., Ltd.) Was operated in the same manner as in Example 2 except that 1: 1 was mixed. Table 3 shows the results.

Examples 11 and 12 and Comparative Examples 19 and 20 The same operation as in Example 6 was carried out except that the solidified products obtained in Examples 7 and 8 and the solids obtained in Comparative Examples 15 and 16 were used. . Table 4 shows the results.

Example 13 In a reaction vessel equipped with a reflux condenser, 250 parts of ion-exchanged water, SD
After 1.0 part of OSS was charged and nitrogen was blown in under stirring to make it free from the influence of oxygen, 0.1 part of Rongalite was charged and the temperature was raised to 70 ° C. Then 46.4 BA, ST1
A monomer mixture consisting of 6.2 parts, 0.6 parts of ALMA, and 0.13 parts of CHP was continuously added over 200 minutes, and the mixture was kept for 90 minutes after completion of the addition.

Then, in the presence of this latex, MMA
31.5 parts, ST1.5 parts, CHMI 4.5 parts, n-O
A monomer mixture consisting of 0.07 part of M and 0.04 part of CHP was continuously added over 30 minutes, and 60 minutes after the addition was completed.
After holding for 2 minutes, a two-layer polymer latex was obtained.

Then, this latex was cooled by cooling at a temperature of -20 ° C. for 8 hours, frozen, then thawed at a temperature of 70 ° C., and washed and dehydrated three times with 70 ° C. hot water.
Dried at 0 ° C. for 10 hours. A smooth coagulate without melting and blocking was obtained, and the average particle size was 220.
It was μ.

Next, the obtained coagulated product and MMA 80%, S
An acrylic resin having a composition of T5% and CHMI15% was mixed at a ratio of 1: 1 and melt-kneaded at a cylinder temperature of 250 ° C. using a 40φ extruder to obtain pellets. Using these pellets, cylinder temperature 250 ° C, mold temperature 50 ° C
To obtain a flat plate of 50 × 50 × 3 mm. As a result of evaluating the optical characteristics using this test piece, the total light transmittance was 9
It was 1.8 (%) and the yellow index was 3.5.
Further, as a result of the hot water resistance test, the Δ haze value was 5.0.

COMPARATIVE EXAMPLE 21 The final latex obtained in Example 13 was subjected to salting-out aggregation at 70 ° C. using twice the amount of a 3% aqueous sodium chloride solution, and then dried at 90 ° C. for 10 hours. . The solid was fused and blocked, so the condition was 60 ° C.-1
The drying time was changed to 5 hours. Otherwise, the operation was performed in the same manner as in Example 6 to evaluate the characteristics.
5 (%), Yellow Index 9.0, ΔHaze value of hot water resistance test was 45, and only inferior one was obtained as compared with Example 13.

[0071]

According to the acrylic polymer coagulated product and the acrylic polymer composition of the present invention, handling properties are remarkably improved in the filtration, washing and drying steps, and the extrusion stability is also improved. Is very easy and industrially excellent effects are exhibited. In addition, a molded article excellent in optical properties such as low thermal coloring and excellent in hot water resistance and impact resistance can be obtained.

Continuation of the front page (72) Inventor Mitsuo Otani 2-28 Kurashiki-cho, Nakajo-cho, Kitakanbara-gun, Niigata Kuraray Co., Ltd. Examiner Kunihiko Sato (56) References JP-A-4-356502 (JP, A) (58) Surveyed field (Int.Cl. ⁷ , DB name) C08F 6/22 B32B 27/30 C08F 2/22 C08F 220/18 C08F 285/00

Claims (4)

(57) [Claims] 1. A multilayered polymer obtained by an emulsion polymerization method, wherein the outermost layer of the multilayered polymer comprises (1)
At least one methacrylate unit 40 to 10
0% by weight, other monomer units 0 to 6 copolymerizable therewith
A hard layer having a glass transition temperature of 25 ° C. or more when polymerized by the layer alone, wherein at least one of the inner layers comprises (2) at least one acrylic ester unit 40 ９９99.9% by weight, 0-60% by weight of other monomer units copolymerizable therewith, and 0.1-5% by weight of a polyfunctional monomer unit. Acrylic polymer coagulate, characterized in that it is a soft layer having a glass transition temperature of less than 25 [deg.] C. when subjected to a freeze-coagulation process at a rate of 4 cm / hr or less. . 2. An average particle size of 20 to 2000 μm.
The coagulated acrylic polymer according to claim 1. 3. The outermost layer is (1) a layer comprising 40 to 100% by weight of at least one methacrylate unit and 0 to 60% by weight of another monomer unit copolymerizable therewith. A hard layer having a glass transition temperature of 25 ° C. or more when polymerized alone, wherein at least one of the inner layers comprises (2) at least one acrylate unit 4
0 to 99.9% by weight, 0 to 60% by weight of other monomer units copolymerizable therewith, and 0.1 to 5% by weight of a polyfunctional monomer unit. 25 when polymerized
A latex of a multi-layered polymer, which is a soft layer having a glass transition temperature of less than 0 ° C., is produced by an emulsion polymerization method, and the latex is frozen at a rate of 4 cm / hr or less, melted, and dehydrated to form a multilayer from the latex. A method for producing an acrylic polymer coagulate, comprising separating a structural polymer. 4. The method for producing a coagulated acrylic polymer according to claim 3 , wherein the melting temperature is 40 to 100 ° C.