JP3059201B2 - Thermoplastic resin composition and multi-stage rigid polymer suitable for the same - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a thermoplastic resin composition and a multi-stage rigid polymer suitable for the composition. More specifically, a thermoplastic resin composition having improved solvent resistance without impairing the inherent properties of the intended resin such as fluidity, transparency, heat resistance, mechanical strength, and weather resistance, and a thermoplastic resin composition suitable for the composition. It relates to a step hard polymer.

[Conventional technology and problems to be solved]

Regarding the improvement of the solvent resistance of a thermoplastic polymer, a method of incorporating an oligomer or copolymerizing a certain effective copolymerizable monomer has been proposed. However, the method of adding an oligomer tends to cause defects such as a decrease in mechanical strength or the occurrence of silver at the time of molding, and the method of copolymerizing an effective monomer has little or no effect with a small amount. It is necessary to use a large amount in order to obtain the desired polymer, which is not preferable because the basic properties of the desired polymer cannot be maintained. On the other hand, solvent resistance can be improved by increasing the molecular weight of the thermoplastic polymer itself having the desired composition, but in this method, the molecular weight must be very large to obtain a substantial effect. Is required, the flowability is reduced, and the moldability is deteriorated, which is not preferable. At present, only an incomplete improvement effect is obtained from the compatibility with the moldability.

Therefore, an object of the present invention is to provide a thermoplastic resin composition which does not have the above-mentioned drawbacks and problems, retains the inherent properties of the resin to be obtained, and has significantly improved solvent resistance. is there.

[Means for solving the problem]

The present inventor has conducted intensive studies on a thermoplastic resin composition having excellent solvent resistance while retaining various properties of the resin, and by allowing the thermoplastic resin to contain a specific multi-stage hard polymer, the The inventors have found that the object has been achieved and completed the present invention.

That is, the gist of the present invention is to provide a thermoplastic resin composition obtained by mixing 95 to 5 parts by weight of the following multistage hard polymer with 5 to 95 parts by weight of a thermoplastic polymer, and a thermoplastic resin composition suitable for the composition. It is a step hard polymer.

Multi-stage rigid polymer: A) 30-90% by weight of inner layer polymer and 70-10% of outer layer polymer
B) at least one monomer selected from the group consisting of alkyl methacrylate having an alkyl group having 1 to 4 carbon atoms, styrene which may have a substituent, and (meth) acrylonitrile; A polymer comprising 0 to 40% by weight of another copolymerizable monoethylenically unsaturated monomer and 0.1 to 5% by weight of a crosslinkable monomer or a graftable monomer. C) an alkyl methacrylate having an alkyl group having 1 to 4 carbon atoms and a substituent, on at least one layer of the inner layer polymer having a Tg of 25 ° C. or more and a particle diameter of 0.03 to 0.7 μm before forming the outer layer. At least one monomer selected from styrene and (meth) acrylonitrile which may be 60 to 100% by weight, and 40 to 0% by weight of another copolymerizable monoethylenically unsaturated monomer. Polymerization alone A is a Tg of 25 ° C. or higher when allowed, and 20 ° C. intrinsic viscosity measured in chloroform at least one layer of the outer layer polymer is 0.3~1dl / g, made be present multi-stage hard polymer.

 Hereinafter, the present invention will be described in detail.

Examples of the thermoplastic polymer used in the present invention include acrylic resin, polystyrene, AS resin, vinyl chloride resin and the like, and alkyl methacrylate having 1 to 4 carbon atoms,
A polymer comprising at least one monomer selected from styrene and (meth) acrylonitrile which may have a substituent, or a monomer mixture mainly composed of these monomers is preferably used.

Alkyl methacrylate, which is one of the monomers preferably used in the thermoplastic polymer, includes methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, sec-butyl methacrylate, and Styrene which may have a substituent includes styrene, α-methylstyrene, p-methylstyrene, t
-Butylstyrene, monochlorostyrene and the like. Of these monomers, methyl methacrylate and styrene are particularly preferably used. Further, as the copolymerizable monoethylenically unsaturated monomer, methyl acrylate, ethyl acrylate, n-butyl acrylate, cyclohexyl acrylate, acrylates such as phenyl acrylate, 2-ethylhexyl methacrylate, cyclohexyl methacrylate, phenyl methacrylate, Methacrylic esters such as benzyl methacrylate, isobornyl methacrylate, and tricyclodecyl methacrylate, and maleimide compounds such as n-phenylmaleimide, o-chlorophenylmaleimide, methylmaleimide, and cyclohexylmaleimide can be used.

As the thermoplastic polymer, those obtained by known methods such as bulk polymerization, suspension polymerization, emulsion polymerization, and solution polymerization can all be used, and can be blended with the following multistage rigid polymer by a known method. The blending ratio is 5 to 95 parts by weight of the thermoplastic polymer,
More preferably, 20 to 90 parts by weight and 95 to 5 parts of multi-stage hard polymer.
Parts by weight, more preferably 80 to 10 parts by weight. If the compounding ratio of the multi-stage hard polymer is less than 5 parts by weight, the solvent resistance is not improved and is not preferable. On the other hand, if it exceeds 95 parts by weight, the surface properties of the molded article may be undesirably reduced.

The inner layer of the multi-stage rigid polymer of the present invention comprises at least one monomer selected from the group consisting of alkyl methacrylate having an alkyl group having 1 to 4 carbon atoms, styrene which may have a substituent and (meth) acrylonitrile. 60 to 99.9% by weight of a copolymerizable other monoethylenically unsaturated monomer
40% by weight, crosslinkable monomer or graftable monomer 0.1 to 5
% By weight, and a Tg obtained by emulsion polymerization of these monomer mixtures is at least one or more hard polymers having a temperature of 25 ° C. or more, and may have two or more layers if necessary. The inner layer, when blended with a thermoplastic polymer, has a property of substantially not affecting the fluidity and imparting solvent resistance. It is necessary that the addition amount of the monomer or the grafting monomer is 0.1% by weight or more. On the other hand, if it exceeds 5% by weight, the crosslinking effect is sufficient but the residual amount of the monomer increases, which is not preferable. In addition, it is preferable that the addition amount of a crosslinking monomer or a grafting monomer is 0.2 to 3% by weight.

Specific examples of the crosslinkable monomer used in the present invention,
For example, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, dipropylene glycol dimethacrylate, trimethylolpropane trimethacrylate, tetramethylolmethane tetramethacrylate, neopentyl glycol dimethacrylate, 1,3
-Butanediol dimethacrylate, 1,4-butanediol dimethacrylate, dimethacrylates such as 1,6-hexanediol dimethacrylate, and corresponding diacrylates, divinylbenzene, divinyl adipate, and the like, Specific examples of the grafting monomer include, for example, allyl methacrylate, allyl acrylate, diallyl phthalate, diallyl maleate, triallyl cyanurate and the like.
Species or a combination of two or more can be used.

The particle size of the inner layer before polymerizing the outer layer is 0.03-0.7μ
m, preferably 0.05 to 0.5 μm.

The particle size of the inner layer latex is adjusted by the type and amount of the emulsifier. The emulsifier in the present invention is not particularly limited and known ones can be used.For example, long-chain fatty acid salts, sulfonates, sulfosuccinic acid ester salts,
Phosphate ester salts and the like.

Next, the outer layer of the multi-stage rigid polymer of the present invention has a carbon number of 1
At least one monomer selected from the group consisting of alkyl methacrylate having 1 to 4 alkyl groups, styrene which may have a substituent and (meth) acrylonitrile;
0% by weight, consisting of 40 to 0% by weight of another copolymerizable monoethylenically unsaturated monomer, and Tg when polymerized alone is
A monomer or monomer mixture adjusted to form a polymer having an intrinsic viscosity of 0.3 to 1.0 dl / g measured in chloroform at 25 ° C. or higher and in the presence of an inner layer polymer. It is at least one hard polymer obtained by polymerizing the polymer. Tg in the present invention is the glass transition temperature, Tg of each layer of the multi-stage hard polymer is 25 ° C. or more, preferably 50 ° C.
That is all. The ratio of the inner layer and the outer layer of the multi-stage hard polymer thus constituted is 30 to 90% by weight, preferably 40 to 80% by weight of the hard polymer as the inner layer, and 70 to 10% by weight of the hard polymer as the outer layer. Parts, preferably 60 to 20 parts by weight. The outer layer must have good compatibility with the thermoplastic polymer and styrene or methyl methacrylate is preferably used as the main monomer, but the monomer or monomer mixture used in the outer layer is preferably used. When polymerized alone, the intrinsic viscosity of the obtained polymer measured at 20 ° C in chloroform is 0.3 to 1 dl / g, preferably 0.1 to 0.1 dl / g.
The composition of the outer layer or the fluidity is adjusted so as to be in the range of 4 to 0.9 dl / g. If the intrinsic viscosity is less than 0.3 dl / g, the effect of improving the solvent resistance is lowered, which is not preferable.
If it exceeds g, the surface properties decrease, which is not preferable.

As the main monomer of the inner layer polymer or outer layer polymer of the multi-stage hard polymer, alkyl methacrylate having an alkyl group having 1 to 4 carbon atoms, styrene which may have a substituent and (meth) ) At least one monomer selected from acrylonitrile is used, but a monomer preferably used in the thermoplastic polymer is desirable, and methyl methacrylate and styrene are particularly desirable. The combination of the main monomer of the inner layer polymer and the main monomer of the outer layer polymer may be styrene / styrene, styrene / methyl methacrylate, methyl methacrylate / styrene, methyl methacrylate / methyl methacrylate in relation to the thermoplastic polymer. Are preferred.

Such a multi-stage rigid polymer is obtained by polymerizing the second layer after the completion of the polymerization of the first layer, and then, in the presence of the produced polymer, as in the third layer, the subsequent monomer or monomer mixture, respectively. It can be simply and easily produced by a known technique of adding and emulsion polymerization. The polymerization temperature during emulsion polymerization is usually 30 to 13
The reaction is carried out at 0 ° C., preferably 50 to 100 ° C., and the polymer latex obtained by the emulsion polymerization method is coagulated and dried by a known method.

Examples of the polymerization catalyst used in the emulsion polymerization include persulfates such as potassium persulfate and ammonium persulfate, and redox initiators such as cumene hydroperoxide / sodium formaldehyde sulfoxylate and diisopropylbenzene hydrohardoxide / sodium formaldehyde sulfoxylate. No. As the chain transfer agent, alkyl mercaptans such as n-octyl mercaptan, n-dodecyl mercaptan, t-dodecyl mercaptan, thioglycolate, β-mercaptopropionate, and thioglycolic acid can be used.

When polymerizing or blending the resin composition of the present invention, an ultraviolet absorber, an antioxidant, a lubricant, a mold release agent, a dye or the like can be added as needed within a range that achieves the object of the present invention.

〔Example〕

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited thereto.

In the examples, "parts" are all "parts by weight", and abbreviations of monomers, polymerization initiators, chain transfer agents and the like used are as follows.

Methyl methacrylate… MMA Methyl acrylate… MA Ethyl acrylate… EA n-butyl acrylate… BA Styrene… ST Acrylonitrile… AN Allyl methacrylate… ALMA 1,3-butylene glycol dimethacrylate… BGDMA 1,4-butanediol dimethacrylate… BDDMA persulfate Potassium ... KPS n-octylmercaptan ... n-OM In Tables 1, 2 and 3, a horizontal line (-) is used to separate monomers used to form the same layer. The diagonal lines () are used when the layers are different.

The property evaluation of the resin composition and the multi-stage hard polymer in the examples was measured by the following methods.

(1) Solvent resistance Evaluated by the cantilever method. Board thickness 3mm, width 20mm,
A cloth impregnated with brake oil was placed on the fulcrum under the condition that the length from the fulcrum to the load was 120 mm and the fulcrum stress was 400 kg / cm ² , and the time required for the test piece to break was measured.

(2) Heat deformation temperature: HDT ASTM-D648 (246 psi) (3) MFR ASTM-D1238, I condition (230 ° C, 3.8 kg) (4) Particle size It was measured with an electron microscope.

Example 1 (1) Production of multi-stage rigid polymer (A) 250 ion-exchanged water was placed in a reaction vessel equipped with a reflux condenser.
And 1 part of sodium dioctylsulfosuccinate, and heated to 80 ° C. while stirring under a nitrogen stream.
Parts, MA2 parts, ALMA 0.6 parts, 1% KPS aqueous solution 6 parts
The polymerization was completed by reacting for 0 minutes. At this time, the particle size of the latex was 0.13 μm. Next, when 4 parts of a 1% KPS aqueous solution was charged, 37 parts of MMA, 3 parts of MA, and n-OM0.
The monomer mixture consisting of 08 parts was dropped continuously for 60 minutes, and the whole amount was charged. Then, the mixture was held for 60 minutes to complete the polymerization. The resulting latex containing the multi-stage rigid polymer was subjected to salting out and coagulation using magnesium sulfate, followed by washing with water, dehydration and drying to obtain a multi-stage rigid polymer (A). The composition and various properties of this multi-stage hard polymer are shown in Table 2 (A).

(2) Production of Resin Composition A mixture of 95 parts of MMA and 5 parts of MA, 70 parts of rigid thermoplastic polymer beads (a) of 10.0 g / 10 minutes MFR and 30 parts of the multi-stage rigid polymer (A) are mixed, Pellets were formed by an extruder equipped with a 40φ vent, and test pieces were prepared and evaluated by an injection molding machine. As a result, the moldability was good, the transparency was excellent, and the solvent resistance was significantly improved. Table 3 shows these detailed results.

Examples 2 to 9 The multi-stage hard polymers (B) to (G) were obtained by changing the type and amount of the emulsifier and using the monomer-containing composition shown in Table 2 and the same polymerization method as in Example 1. . Table 2 shows the compositions and properties of these polymers. Next, the hard thermoplastic polymers (b) to (e) having different compositions and MFRs shown in Table 1 were mixed with the multi-stage hard polymer, and the results were evaluated in the same manner as in Example 1. As shown in the table, the moldability was all good, and the solvent resistance showed a remarkable improvement effect.

Comparative Examples 1 to 3 Table 3 shows the evaluation results of the thermoplastic polymer (a) alone and those in which the mixture of the thermoplastic polymer and the multi-stage hard polymer deviated from the scope of the present invention.

Comparative Example 4 A multi-step hard polymer (H) was obtained by using the same polymerization method as in Example 1, but the content of the crosslinkable monomer unit in the inner layer was out of the range of the present invention. The composition is shown in Table 4. Table 5 shows the results of mixing and evaluating 30 parts of the multi-stage hard polymer (H) and 70 parts of the thermoplastic polymer (b).
It was non-uniform and translucent, poor in moldability, and no improvement in solvent resistance was observed.

Comparative Example 5 A multi-stage hard polymer (I) was obtained by using the same polymerization method as in Example 1, but the composition ratio of 20 parts of the inner layer and 80 parts of the outer layer deviated from the scope of the present invention. The composition is shown in Table 4. As a result of mixing and evaluating 60 parts of the multi-stage hard polymer (I) and 40 parts of the thermoplastic polymer (a), the appearance such as moldability and surface properties was good, but the effect of improving the solvent resistance was little. Did not. Table 5 shows the results.

Comparative Examples 6 and 7 Multi-stage hard polymers (J) and (K) were obtained by using the same polymerization method as in Example 1, but at least one of the requirements departed from the scope of the present invention. Was. The compositions and the evaluation results are shown in Tables 4 and 5. As a result, the solvent resistance was good, but both were non-uniform, and the molded product had poor surface properties and produced bumps.

Comparative Example 8 Using the same polymerization method as in Example 1, a hard polymer (L) consisting of only the inner layer was obtained and mixed with the hard thermoplastic polymer (b) for evaluation. Poor, and occurrence of bumps was observed on the surface of the obtained formed product. The compositions and results are shown in Tables 4 and 5.

[Effects of the Invention] As described above, the present invention relates to thermoplastic polymers 5 to 5.
95 to 5 parts by weight of a specific multi-stage hard polymer is a thermoplastic resin composition comprising 95 to 5 parts by weight, so that the desired heat, such as fluidity, transparency, heat resistance, mechanical properties, and weather resistance A resin composition having significantly improved solvent resistance can be obtained without impairing the required performance and various properties of the plastic resin body. Further, since the present invention is a multi-stage hard polymer suitable for obtaining the thermoplastic resin composition, it can be easily and easily produced, and the thermoplastic resin composition suitable for the purpose by adjusting the content. Is useful.

Claims (2)

(57) [Claims] 1. A thermoplastic resin composition comprising 5 to 95 parts by weight of a thermoplastic polymer and 95 to 5 parts by weight of the following multistage hard polymer. Multi-stage rigid polymer: A) 30-90% by weight of inner layer polymer and 70-10% of outer layer polymer
B) at least one monomer selected from the group consisting of alkyl methacrylate having an alkyl group having 1 to 4 carbon atoms, styrene which may have a substituent, and (meth) acrylonitrile; A polymer comprising 0 to 40% by weight of another copolymerizable monoethylenically unsaturated monomer and 0.1 to 5% by weight of a crosslinkable monomer or a graftable monomer. C) an alkyl methacrylate having an alkyl group having 1 to 4 carbon atoms and a substituent, on at least one layer of the inner layer polymer having a Tg of 25 ° C. or more and a particle diameter of 0.03 to 0.7 μm before forming the outer layer. At least one monomer selected from styrene and (meth) acrylonitrile which may be 60 to 100% by weight, and 40 to 0% by weight of another copolymerizable monoethylenically unsaturated monomer. Polymerization alone A is a Tg of 25 ° C. or higher when allowed, and 20 ° C. intrinsic viscosity measured in chloroform at least one layer of the outer layer polymer is 0.3~1dl / g, made be present multi-stage hard polymer. 2. A) 30 to 90% by weight of an inner layer polymer and 70 to 10% by weight of an outer layer polymer. B) Alkyl methacrylate having an alkyl group having 1 to 4 carbon atoms, even if it has a substituent. 60 to 99.9% by weight of at least one monomer selected from good styrene and (meth) acrylonitrile, 0 to 40% by weight of another copolymerizable monoethylenically unsaturated monomer, and a crosslinkable monomer or An inner-layer polymer obtained by emulsion-polymerizing 0.1 to 5% by weight of a grafting monomer, wherein the polymer has a Tg of 25 ° C. or more and a particle diameter before forming an outer layer of 0.03 to 0.7 μm. C) at least one monomer selected from the group consisting of alkyl methacrylate having an alkyl group having 1 to 4 carbon atoms, styrene optionally having substituent (s) and (meth) acrylonitrile; %, Copolymerizable, etc. The monoethylenically unsaturated monomer is composed of 40 to 0% by weight, and when these are independently polymerized, the Tg is 25 ° C. or more and the intrinsic viscosity measured in chloroform at 20 ° C. is 0.3 to 1 dl / g. A multi-stage hard polymer in which at least one outer layer polymer is present.