JPH07300547A - Production of impact resistant methacrylic resin composition - Google Patents

Abstract

PURPOSE:To obtain the title compsn. free from hard spots by compounding a multilayered polymer comprising a soft polymer layer formed mainly from an alkyl acrylate and a hard polymer layer formed mainly from an alkyl methacrylate into the compsn. CONSTITUTION:A multilayered polymer which comprises a soft polymer layer formed from 50-99.9wt.% 1-8C alkyl acrylate, 0-50wt.% unsatd. monomer, and 0.1-5wt.% polyfunctional cross-linking or graft monomer and a hard polymer layer formed from 50-100wt.% 1-4C alkyl methacrylate, 0-50wt.% unsatd. monomer, and 0-5wt.% polyfunctional cross-linking or graft monomer and which contains at least 10wt.% the outermost layer comprising the alkyl methacrylate and the unsatd. monomer is produced by successive emulsion polymn. 10-60 pts.wt. thermoplastic polymer formed by the emulsion polymn. of 50-100wt.% 1-8C alkyl acrylate and 0-50wt.% unsatd. monomer and 40-90 pts.wt. the multilayered polymer are mixed in the state of latex and coagulated to give an impact modifier. The modifier is perfectly compatible with a hard methacrylic resin and is compounded in an amt. of 10-80 pts.wt. into 100 pts.wt. the resin.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to the production of a methacrylic impact-resistant resin composition which is excellent in the dispersibility of fine particles of a polymer having a multilayer structure and which gives injection-molded articles, extruded sheets and films in which the generation of lumps is remarkably improved. Regarding the method.

[0002]

BACKGROUND OF THE INVENTION Methacrylic resin is colorless and transparent, has a beautiful appearance and weather resistance, and is easy to mold. Therefore, electrical parts such as louvers, tail lamps, lenses, tableware, vehicle parts, optical applications, decorations, miscellaneous goods, and signboards. However, its strength against impact is not always sufficient, and many improvements and modifications have been studied, and it has been commercialized as a methacrylic impact resistant resin. However, although these commercially available methacrylic impact-resistant resins satisfy the target impact resistance to some extent, the impact-modifying agent added and mixed with a general-purpose methacrylic resin is not completely compatible but particles. Since they are dispersed in a shape, the presence of agglomerates or coagulates of particles is the cause of lumps, and a small amount of lumps are observed as lumps on the surface, especially during the sheet forming process or in the case of a thin film. At present, there is no satisfactory product.

[0003]

DISCLOSURE OF THE INVENTION The present invention provides a methacrylic impact-resistant resin composition which is excellent in the dispersibility of multi-layered polymer fine particles and in which the generation of spots in injection molded articles, extruded sheets and films is remarkably improved. The purpose is to find a method for manufacturing a product.

[0004]

Means for Solving the Problems The inventors of the present invention have made earnest studies on a methacrylic impact-resistant resin in which the generation of seeds is remarkably improved. As a result, the inventors have obtained a multilayer structure polymer and a hard thermoplastic polymer obtained by emulsion polymerization. Is uniformly mixed in a latex state, then coagulated by an arbitrary method and taken out to obtain an impact resistance improver, and then melt-mixed with a hard methacrylic resin so that the dispersibility of fine particles of a multilayer structure polymer is very good. Then, it was found that the generation of seeds was remarkably improved, and the method for producing the methacrylic impact-resistant resin composition of the present invention was completed. That is, the present invention includes (1) 50 to 99.9% by weight of at least one alkyl acrylate in which the alkyl group has 1 to 8 carbon atoms, and 0 to 50% by weight of an unsaturated monomer copolymerizable therewith. , At least one soft polymer layer obtained by polymerizing a monomer mixture containing 0.1 to 5% by weight of a polyfunctional crosslinking monomer and / or a polyfunctional grafting monomer, and the number of carbon atoms of an alkyl group. 50 to 100% by weight of at least one alkyl methacrylate having 1 to 4; 0 to 50% by weight of an unsaturated monomer copolymerizable therewith, a polyfunctional crosslinking monomer, and / or a polyfunctional graft monomer At least one alkyl having at least one hard polymer layer formed by polymerizing a monomer mixture of 0 to 5% by weight, and the outermost layer having at least one alkyl group having 1 to 4 carbon atoms. Methacrylate 50-100 % By weight, 0 to 50% by weight of unsaturated monomer copolymerizable with these
And a multilayer structure polymer 40 comprising a hard polymer layer obtained by polymerizing a monomer mixture in which the ratio of the outermost layer to the total amount of the soft polymer layer and the hard polymer layer is 10% by weight or more.
To 90 parts by weight, and (2) at least one alkyl methacrylate having 10 to 4 carbon atoms in the alkyl group 50 to 10
0% by weight, 0 to 50 unsaturated monomers copolymerizable with these
After uniformly mixing 10 to 60 parts by weight of a hard thermoplastic polymer obtained by emulsion-polymerizing a monomer mixture composed of 1% by weight in a latex state, the mixture is coagulated to obtain an impact resistance improver, and (3) At least one alkyl methacrylate having an alkyl group having 1 to 4 carbon atoms 50 to 100
20 to 90 parts by weight of a hard methacrylic resin obtained by polymerizing a monomer mixture consisting of 0 to 50% by weight of an unsaturated monomer copolymerizable therewith, and an impact modifier 10 to 80.
This is achieved by a method for producing a methacrylic impact-resistant resin composition having excellent dispersibility of multi-layered polymer fine particles, which is characterized by melt-mixing parts by weight.

The particle size of the multi-layer structure polymer of the present invention is not particularly limited, but is preferably 0.08 to 0.35 μm, and if the particle size exceeds 0.40 μm, the generation of seeds is increased, which is not preferable. .

The particle size of the hard thermoplastic polymer of the present invention is not particularly limited, but is preferably 0.03 to 0.30 μm, more preferably smaller than the particle size of the multilayer structure polymer. The addition amount of the hard thermoplastic polymer is 10 to 60 parts by weight. When it is less than 10 parts by weight, the dispersion of the fine particles of the multilayer structure polymer is not preferable, and when it exceeds 60 parts by weight, there is a problem in terms of productivity. Further, the molecular weight of the hard thermoplastic polymer is preferably 40,000 to 130,000 in terms of weight average molecular weight, although it varies slightly depending on the composition of the hard thermoplastic polymer. When it is 40,000 or less, the impact strength is lowered, which is not preferable.

The method for producing a methacrylic impact-resistant resin composition of the present invention is a method in which a multilayer structure polymer obtained by emulsion polymerization and a hard thermoplastic polymer are uniformly mixed in a latex state and then coagulated, An impact resistance improver is obtained and then melt-mixed with a hard methacrylic resin.

Known methods are used for emulsion polymerization to obtain the multilayer structure polymer and the rigid thermoplastic polymer of the present invention. The type and amount of the emulsifier used in the emulsion polymerization is selected depending on the stability of the polymerization system, the target particle size, etc.
Well-known emulsifiers such as anionic surfactants, cationic surfactants and nonionic surfactants can be used alone or in combination, and anionic surfactants are particularly preferable. The polymerization initiator used for emulsion polymerization is not particularly limited, and persulfate-based or redox-based initiators are used. Further, a chain transfer agent such as alkyl mercaptan is used if necessary.

In emulsion polymerization, monomers, emulsifiers, polymerization initiators, chain transfer agents and the like are added by any method such as a batch addition method, a divided addition method, and a continuous addition method.

The method of uniformly mixing and latex-coagulating each polymer latex obtained by emulsion polymerization is not particularly limited, and a salting-out method, an aciding-out method, a spraying method, a freezing method and the like are possible.

The multilayer structure polymer of the present invention comprises at least 1
One or more soft polymer layers and at least one or more hard polymer layers, and the outermost layer is a hard polymer layer. From the viewpoint of impact resistance and weather resistance, the soft polymer layer in the multi-layer structure polymer has at least one alkyl acrylate having an alkyl group having 1 to 8 carbon atoms in an amount of 50 to 9
The main monomer is 9.9% by weight, the unsaturated monomer copolymerizable with these is 0 to 50% by weight, the polyfunctional crosslinking monomer and / or the polyfunctional grafting monomer is 0.1 to 5%. It consists of weight percent. As the alkyl acrylate used for the soft polymer layer, methyl acrylate, ethyl acrylate, n-
Examples thereof include butyl acrylate, i-butyl acrylate, 2-ethylhexyl acrylate, cyclohexyl acrylate, and benzyl acrylate, which may be used alone or in combination. As the unsaturated monomer copolymerizable with these, 1,3-butadiene, 2,3-butadiene,
Examples thereof include isoprene, styrene, α-methylstyrene, vinyltoluene, methylmethacrylate, ethylmethacrylate, butylmethacrylate, cyclohexylmethacrylate, benzylmethacrylate, acrylonitrile, methacrylonitrile and the like, and these are used alone or in combination. As the polyfunctional crosslinkable monomer, ethylene glycol di (meth) acrylate, 1,3-butylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, divinylbenzene, etc. may be used. Examples thereof include allyl methacrylate, allyl acrylate, allyl maleate, allyl fumarate, diallyl fumarate, triallyl cyanurate and the like, which may be used alone or in combination.

The hard polymer layer of the multi-layered polymer has an alkyl group having 1 to 4 carbon atoms from the viewpoint of transparency and weather resistance.
At least one alkyl methacrylate of 50 to 10
0% by weight is used, particularly preferably methyl methacrylate. The monomer copolymerizable with these is 0 to 50% by weight of an unsaturated monomer, 0 to 5% by weight of a polyfunctional crosslinking monomer and / or a polyfunctional grafting monomer,
All monomers used in the soft polymer layer including alkyl acrylate can be used.

The outermost layer of the multilayer structure polymer is composed of a hard polymer layer from the viewpoint of compatibility with a general-purpose methacrylic resin, and the ratio of the outermost layer to the total amount of the soft polymer layer and the hard polymer layer is 10%. It is more than weight%. As the monomer constituting the outermost layer, like the above-mentioned hard polymer, 50 to 100% by weight of at least one alkyl methacrylate having an alkyl group having 1 to 4 carbon atoms is used in terms of transparency and weather resistance. Especially preferred is methyl methacrylate. The monomer copolymerizable with these is 0 to 50% by weight of an unsaturated monomer, and is used in the hard polymer layer except the polyfunctional crosslinkable monomer and the polyfunctional graft monomer. All the given monomers can be used. Further, a chain transfer agent such as n-octyl mercaptan or n-dodecyl mercaptan is preferably used from the viewpoint of compatibility with the hard methacrylic resin to be melt-kneaded.

The multi-layer structure polymer of the present invention is obtained as a polymer latex by sequentially emulsion-polymerizing a monomer mixture for each of these layers.

From the viewpoint of transparency and weather resistance, the rigid thermoplastic polymer of the present invention has at least one alkyl methacrylate having 100 to 4 carbon atoms in the alkyl group and 50 to 100.
% By weight, particularly preferably methyl methacrylate. Further, as the monomer copolymerizable with these,
Unsaturated monomer is 0 to 50% by weight, and all the monomers used in the hard polymer layer of the above-mentioned multilayer structure polymer except the polyfunctional crosslinkable monomer and the polyfunctional graft monomer are used. it can. Further, a chain transfer agent such as n-octyl mercaptan or n-dodecyl mercaptan is preferably used from the viewpoint of compatibility with the multilayer structure polymer and a general-purpose methacrylic resin. Further, the hard thermoplastic polymer can be obtained as a polymer latex by emulsion polymerization of these monomer mixtures.

The method for producing the methacrylic impact-resistant resin composition of the present invention is obtained by uniformly mixing the above-mentioned respective polymer latexes in a latex state, then coagulating and separating by any coagulating method and drying. Specific impact modifier 1 which may be a coagulum or a mixture of different coagulates 1
0 to 80% by weight and specific hard methacrylic resin 20 to 9
The methacrylic impact-resistant resin composition thus obtained is characterized by being melt-mixed in an amount of 0% by weight, and the methacrylic impact-resistant resin composition thus obtained is processed into an injection molding material such as pellets and into a sheet and a film by an extruder.

UV absorbers, antioxidants, lubricants, dyes and pigments, etc., which are commonly used in methacrylic resins, can be added as required.

Injection moldings, extruded sheets / films and their processed products made of the methacrylic impact-resistant resin composition obtained by the production method of the present invention are remarkably improved in generation of seeds.

[0019]

EXAMPLES The present invention will now be described in detail with reference to examples, but the present invention is not limited thereto.
All "%" and "parts" in the examples are "% by weight" and "parts by weight", and the monomer used, the polymerization initiator,
The following are used as abbreviations of chain transfer agents and the like.

Methyl methacrylate (MMA), methyl acrylate (MA), ethyl acrylate (EA),
n-butyl acrylate (BA), styrene (ST),
Allyl methacrylate (ALMA), 1,3-butylene glycol dimethacrylate (BGDMA), n-octyl mercaptan (n-OM). A horizontal line (-) is used to separate the monomers used to form the same layer,
Diagonal lines (/) mean the layers are different.

The physical properties of the methacrylic impact-resistant resin composition and the occurrence of spots in the examples are as follows: a 3 mm extruded plate obtained by a 50φ sheet extruder equipped with three mirror surface rolls, and injection molding after pelletization. It was evaluated by a 3 mm mirror flat plate obtained by a machine.

The following abbreviations are used to evaluate the occurrence of seeds. Very many spots ... ×× Spots exist ×× No spots ... ○ Physical properties of the resin compositions and the like in the examples were measured according to the following methods. (1) Heat distortion temperature; HDT ASTM-D6
48 (264 psi) (2) Izod impact strength (notched) ASTM-D2
56 (3) Total light transmittance, haze ASTM-D1
003 (5 mm thickness) (4) Particle size Measured with an electron microscope. Example 1 (1) Production of multi-layer structure polymer (A-1) latex 200 parts of ion-exchanged water in a reaction tank equipped with a reflux condenser,
Charge 2 parts of sodium stearate, raise the temperature to 80 ° C. with stirring under a nitrogen atmosphere, and then add 19.5 parts of MMA and EA.
0.5 parts, 0.12 parts ALMA monomer mixture,
Polymerization was completed by charging 2 parts of 1% KPS aqueous solution and reacting for 60 minutes. Subsequently, when 5 parts of a 1% KPS aqueous solution was charged, 41.3 parts of BA, ST8.7 parts, and ALM
The monomer mixture consisting of A1 part was continuously added dropwise for 60 minutes, the whole amount was charged, and then held for 60 minutes to complete the polymerization. Then, after charging 3 parts of a 1% KPS aqueous solution, MMA28.
A total of 5 parts, 1.5 parts of MA, and 0.06 part of n-OM was continuously added dropwise over 40 minutes, and then 6 parts were added.
Hold for 0 minutes to complete the polymerization, and then the multilayer structure polymer (A-
1) A latex was obtained. After the completion of the polymerization of each layer, the latex was sampled, and it was confirmed by electron microscope observation that new particles were not generated and the successive polymerization was completely performed. The particle size of the obtained latex was 0.25 μm. The composition of this latex corresponds to (A-1) in Table 1. (2) Production of rigid thermoplastic polymer (B-1) latex 200 parts of ion-exchanged water in a reaction tank equipped with a reflux condenser,
Charge 4 parts of sodium stearate, raise the temperature to 75 ° C. with stirring under a nitrogen atmosphere, and then MMA 47 parts, MA3
Part, a monomer mixture consisting of 0.15 parts of n-OM, and 5 parts of a 1% KPS aqueous solution were charged and reacted for 60 minutes to complete the polymerization. Then, when 1% part and 5 parts of KPS aqueous solution were charged, 47 parts of MMA, 3 parts of MA, and n-OM0.1.
A monomer mixture consisting of 5 parts was continuously added dropwise for 60 minutes, the whole amount was charged, and then the mixture was kept for 60 minutes to complete the polymerization. The particle size of the obtained latex was 0.18 μm. The composition of this latex corresponds to (B-1) in Table 1.

Each of the polymer latexes thus obtained is converted into a polymer, and the multilayer structure polymer (A-1) is obtained.
After 70 parts and 30 parts of the hard thermoplastic polymer (B-1) were uniformly mixed in a latex state, the mixture was added to a 3% magnesium sulfate aqueous solution for salting out and coagulation, followed by washing with water and drying to obtain a polymer powder. 100 parts of the obtained polymer powder and 100 parts of parapet EH beads (extrusion molding grade, manufactured by Kuraray Co., Ltd.), which is a hard methacrylic resin, are mixed with a super mixer and used as an extruded plate with a sheet extruder to generate lumps. And various physical properties were measured and evaluated. The results are shown in Table 2. Example 2 (1) Production of multi-layered polymer (A-2) latex 200 parts of ion-exchanged water in a reaction vessel equipped with a reflux condenser,
Charge 3 parts of sodium dioctyl sulfosuccinate, heat to 85 ° C. with stirring under a nitrogen atmosphere, and then add MMA33.
Part, 2 parts of MA, 0.15 parts of ALMA, and 3.5 parts of a 1% KPS aqueous solution were charged and reacted for 60 minutes to complete the polymerization. Then, when 4.5 parts of 1% KPS aqueous solution was charged, BA36.5 parts, ST8.
A monomer mixture consisting of 5 parts and 1 part of ALMA was continuously added dropwise for 60 minutes to prepare the total amount, and then the mixture was kept for 60 minutes to complete the polymerization. Then, after charging 2 parts of 1% KPS aqueous solution,
The total amount of the monomer mixture consisting of 19 parts of MMA, 1 part of MA, and 0.05 part of n-OM was continuously added dropwise over 40 minutes, and then held for 60 minutes to complete the polymerization, thereby completing the polymerization of the multilayer structure polymer (A
-2) A latex was obtained. After the completion of the polymerization of each layer, the latex was sampled, and it was confirmed by electron microscope observation that new particles were not generated and the successive polymerization was completely performed.
The particle size of the obtained latex was 0.16 μm.
The composition of this latex corresponds to (A-2) in Table 1. (2) Production of hard thermoplastic polymer (B-2) latex 200 parts of ion-exchanged water in a reaction tank equipped with a reflux condenser,
After charging 4 parts of sodium dioctylsulfosuccinate and heating to 80 ° C. with stirring under a nitrogen atmosphere, MMA18
Part, EA 2 parts, nOM 0.05 part, and 1% KPS aqueous solution 2 parts were charged and reacted for 40 minutes to complete the polymerization. Then, when 8 parts of a 1% KPS aqueous solution was charged, M
A monomer mixture consisting of 72 parts of MA and 8 parts of EA was continuously added dropwise for 90 minutes, the whole amount was charged, and then held for 60 minutes to complete the polymerization. The particle size of the obtained latex is 0.07μ
It was m. The composition of this latex is (B-
It corresponds to 2).

Each of the polymer latexes thus obtained is converted into a polymer, and the multi-layer structure polymer (A-2) is obtained.
After 80 parts and 20 parts of the hard thermoplastic polymer (B-2) were uniformly mixed in a latex state, they were freeze-coagulated for 3 hours at -40 ° C, and the ice was melted in warm water at 75 ° C, followed by dehydration /
It was dried to obtain a polymer powder. The obtained polymer powder 100
And 100 parts of Parapet GN beads (injection molding grade, manufactured by Kuraray Co., Ltd.), which is a hard methacrylic resin, were mixed with a super mixer to evaluate the occurrence of seeds and various physical properties. The results are shown in Table 2. Examples 3 to 6 By the same method as in Example 1, the multilayer structure polymers (A-3), (A-4) latex, and the hard thermoplastic polymer (B- 3) A latex was obtained. The number of layers, composition and particle size of these polymers are shown in Table 1.
Shown in.

Table 2 shows the mixing ratio of each polymer in the latex blend, the mixing ratio with the hard methacrylic resin at the time of pelletization and sheet formation, and the evaluation results of the obtained injection-molded flat plate and extruded plate. No spots were observed on the injection-molded flat plates and extruded plates obtained in these examples, and various physical properties satisfying the present invention including Izod impact strength were obtained. The methacrylic resin used in the examples is shown in Table 1. Comparative Examples 1 to 4 The multilayer structure polymer latex and the hard thermoplastic polymer latex in Examples were used, but the mixing ratio of each polymer in the latex blend is outside the scope of the claims of the present invention. However, I couldn't get anything satisfying, including Buu. The results are shown in Table 2.

[0026]

[Table 1]

[0027]

[Table 2]

[0028]

Industrial Applicability As described above, the production method of the present invention is excellent in the dispersibility of multi-layered polymer fine particles imparting impact resistance, and an injection-molded article in which the generation of spots is remarkably improved.
Extruded sheets and films can be supplied, which is particularly effective for products that require impact resistance and good surface properties.

Claims (2)

[Claims] 1. (1) At least one alkyl acrylate in which the alkyl group has 1 to 8 carbon atoms 50 to 99.9
% By weight, 0 to 50% by weight of an unsaturated monomer copolymerizable therewith, a multifunctional crosslinkable monomer and / or a monomer mixture of 0.1 to 5% by weight of a multifunctional grafting monomer. 50 to 100% by weight of at least one soft polymer layer obtained by polymerization, 50 to 100% by weight of an alkyl methacrylate having an alkyl group having 1 to 4 carbon atoms, and 0 to 100 unsaturated monomers copolymerizable therewith. 50% by weight, a polyfunctional crosslinkable monomer, and or at least one hard polymer layer formed by polymerizing a monomer mixture consisting of 0 to 5% by weight of a polyfunctional grafting monomer, The outermost layer is composed of 50 to 100% by weight of at least one kind of alkyl methacrylate having an alkyl group having 1 to 4 carbon atoms, and 0 to 50% by weight of an unsaturated monomer copolymerizable therewith. Total amount with hard polymer layer 40 to 90 parts by weight of a multilayer structure polymer composed of a hard polymer layer obtained by polymerizing a monomer mixture in which the proportion of the outermost layer is 10% by weight or more, and (2) the carbon number of the alkyl group is 1 to 4 10. A hard thermoplastic polymer obtained by emulsion-polymerizing a monomer mixture comprising 50 to 100% by weight of at least one alkyl methacrylate and 0 to 50% by weight of an unsaturated monomer copolymerizable therewith.
-60 parts by weight are uniformly mixed in a latex state and then solidified to obtain an impact resistance improver. (3) At least one alkyl methacrylate having an alkyl group having 1 to 4 carbon atoms 50 to 100 weight%,
20 to 90 parts by weight of a hard methacrylic resin obtained by polymerizing a monomer mixture composed of 0 to 50% by weight of an unsaturated monomer copolymerizable therewith and 10 to 80 parts by weight of an impact modifier are melt-mixed. A method for producing a methacrylic impact-resistant resin composition having excellent dispersibility of multi-layered polymer fine particles. 2. The particle size of the multi-layered polymer is 0.08 to
The method for producing a methacrylic impact-resistant resin composition according to claim 1, wherein the rigid thermoplastic polymer has a particle size of 0.03 to 0.30 μm.