JP2003165888A - Thermoplastic resin composition and molded article thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermoplastic resin composition having transparency or translucency, excellent impact resistance, chemical resistance and thermal stability. <P>SOLUTION: The thermoplastic resin composition contains (A) a graft copolymer obtained by the graft polymerization of a monomer mixture composed of a vinyl cyanide monomer, an aromatic vinyl monomer and optionally other monomers copolymerizable with these monomers to a diene rubber polymer, (B) a rigid polymer produced by the copolymerization of methyl methacrylate, a vinyl cyanide monomer, an aromatic vinyl monomer and optionally other monomers copolymerizable with these monomers, and (C) a polymethyl methacrylate or a copolymer of ≤7 wt.% methyl acrylate and the remaining part of methyl methacrylate. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermoplastic resin composition, and more specifically, it has translucency or semitranslucency, is excellent in chemical resistance and impact resistance, and has thermal stability. It relates to an improved thermoplastic resin composition.

[0002]

2. Description of the Related Art A styrene resin containing a rubbery polymer represented by an ABS resin is excellent in mechanical properties such as impact resistance and molding processability. Further, in order to be used for a wider range of applications, those having excellent chemical resistance, heat resistance and stability against color change due to heat (hereinafter, simply referred to as “heat stability”) have been studied and developed. In recent years, while maintaining the characteristics of such a rubbery polymer-containing styrene resin, such as a casing that can see through the contents of the product,
A resin material having translucency or semitranslucency is required. On the other hand, the rubbery polymer-containing styrene-based resin is widely used in electric appliances such as washing machines, OA equipment and sanitary equipment. The cleaning agents used are becoming more and more powerful, and as a result, cracks occur in the resin parts of the above products, so countermeasures are required.

Since various kinds of demands are simultaneously demanded for a single resin, a light-transmitting or semi-light-transmitting property and a cleaning agent can be obtained while maintaining the mechanical strength of the styrene resin containing a rubbery polymer. There is a strong need for a thermoplastic resin with excellent chemical resistance that can withstand such as.

As a method of exhibiting the light-transmitting property of the rubbery polymer-containing styrene resin, a method of matching the refractive index of the rubbery polymer contained therein with the refractive index of the matrix layer (for example, Encyclopedia of Polymer Science and Te
chnology, vol1, 307-308, 1976), and a method of reducing the particle size of the rubbery polymer within a specific range (for example, Japanese Patent Publication No. 39-8667). The resin obtained by the former method is excellent in transparency and impact resistance, but is poor in chemical resistance and heat resistance because the acrylonitrile unit is blended only in a limited amount of about 15% by weight in the matrix phase. On the other hand, the resin obtained by the latter method is similarly excellent in transparency, but since the particle size of rubber is extremely small, impact resistance is poor, and only extremely poor chemical resistance is obtained. .

Furthermore, in order to improve the transparency of ABS resin and the like, (meth) acrylic acid ester type monomers such as methyl methacrylate (MMA) are commonly used. For example, JP-B-44-15902 discloses a transparent resin composition in which an ABS resin is mixed with a copolymer of MMA, α-methylstyrene and acrylonitrile. However, the obtained resin is apt to produce a silver streak during molding. Further, Japanese Patent Publication No. 47-38541 and Japanese Unexamined Patent Publication No. 52-49262 disclose a transparent resin composition in which an ABS resin is mixed with a copolymer of MMA, styrene and acrylonitrile. However, the former obtained transparency by matching the refractive index of the graft copolymer and the matrix phase, but did not show the original physical properties of the ABS resin, and the latter was sufficient because the amount of MMA in the terpolymer was small. The transparency cannot be obtained. Moreover, all three of them have poor thermal stability in common.

Further, JP-A-61-21152 discloses that ABS resin having a graft ratio of 10 to 40% by weight and a resin containing MMA as a component are mixed to improve transparency, impact resistance and heat resistance. A resin composition having the same is disclosed. However, the resin obtained from this resin composition has poor thermal stability.

Japanese Unexamined Patent Publication No. 63-245461 discloses A
By blending the BS graft polymer and the ternary copolymer consisting of MMA, acrylonitrile and styrene,
Proposals have been made to improve color development and impact resistance.
The technique disclosed in this publication is an improvement in the color developability of the ABS resin, not an improvement in the transparency, but in the composition containing a (meth) acrylic acid ester-based monomer such as MMA, the above-mentioned three Since the original copolymer has poor thermal stability, it discolors to a brown color even with a short residence time in the molding machine. In addition, silver streaks are produced on the surface.

As described above, proposals for improving the transparency of rubbery polymer-containing styrenic resins have not been enumerated in the past, but the original characteristics of rubbery polymer-containing styrenic resins such as ABS resin have been proposed. In particular, there are few proposals that retain impact resistance, and no one that provides chemical resistance and sufficient thermal stability to meet the above requirements has been obtained.

[0009]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems in the prior art, and has translucency or semi-translucency, impact resistance and chemical resistance. An object of the present invention is to provide a thermoplastic resin composition having excellent properties and satisfying thermal stability.

[0010]

Means for Solving the Problems As a result of intensive studies for solving the above problems, the present inventors have found that a specific rubber-containing graft polymer and a hard polymer comprising a vinyl monomer having a specific composition. It has been found that the above object can be achieved by blending a specific amount of methacrylic resin and methacrylic resin, and the present invention has been completed.

That is, the present invention comprises: (A) (A1) diene rubbery polymer, 20 to 90% by weight based on (A); (A2) vinyl cyanide monomer, (A2) to (A2) 25-40% by weight based on the total amount of (A4); (A3) aromatic vinyl monomer, 60-75% by weight based on the total amount of (A2)-(A4); and, if necessary. (A4) another monomer copolymerizable with these monomers,
Monomer mixture consisting of 0 to 20% by weight based on the total amount of (A2) to (A4), 10 to 8 based on (A)
Graft copolymer obtained by graft polymerization of 0% by weight, the total amount of (A) and (B) is set to 100 parts by weight, and 20
To 60 parts by weight; (B) (B1) methyl methacrylate, 45 to 90% by weight based on (B); (B2) vinyl cyanide monomer, 5 based on (B)
50 wt%; (B3) aromatic vinyl monomer, 5 based on (B)
50% by weight; and, if necessary, (B4) another monomer copolymerizable with these monomers,
A hard polymer obtained by copolymerizing 0 to 30% by weight based on (B), 40 to 80 parts by weight based on 100 parts by weight of the total amount of (A) and (B); and (C) polymethacryl Methacrylic resin which is a copolymer of methyl acrylate or methyl acrylate up to 7% by weight based on (C) and the remaining methyl acrylate, and the total amount of (A) and (B) is 100 parts by weight. The present invention relates to a thermoplastic resin composition containing 1 to 10 parts by weight, and a molded article obtained by molding the resin composition.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The component (A) used in the resin composition of the present invention is (A1) a diene rubbery polymer,
2) Obtained by graft-polymerizing a vinyl cyanide monomer, (A3) an aromatic vinyl monomer, and, if necessary, (A4) another monomer copolymerizable with these monomers. It is a graft copolymer. In addition, at the time of graft polymerization, the above (A
2) to (A4) homopolymers or copolymers thereof,
Typically, a small amount of styrene-acrylonitrile copolymer is produced, usually 1 to 20% by weight.
The mixture containing these polymers in the graft copolymer is treated as (A). The graft copolymer is based on (A), (A1) diene rubbery polymer 20-90.
% By weight, preferably 40-80% by weight, the monomer (A
Mixture 1 of 2), (A3) and optionally (A4)
It is obtained by graft copolymerizing 0 to 80% by weight, preferably 20 to 60% by weight. The amount of (A1) in (A) is 2
If the amount is less than 0% by weight or more than 90% by weight, an appropriate graft ratio cannot be obtained, and the impact strength is lowered in any case.

Examples of the (A1) diene rubbery polymer include:
A butadiene-based polymer such as polybutadiene, an isoprene-based polymer such as polyisoprene, a chloroprene-based polymer such as polychloroprene can be used, and a butadiene-based polymer is preferable. Examples of the butadiene-based polymer include polybutadiene and copolymers of vinyl monomers copolymerizable with butadiene. Examples of the copolymerizable vinyl monomer include aromatic vinyl monomers, vinyl cyanide monomers, and (meth) acrylic acid ester-based monomers. As the aromatic vinyl monomer, styrene, α-methylstyrene, o-, m- or p-methylstyrene, vinylxylene, ethylstyrene, pt-butylstyrene, monochlorostyrene, dichlorostyrene, monobromostyrene, Dibromostyrene, fluorostyrene, vinylnaphthalene and the like can be mentioned, and styrene and α-methylstyrene are preferable. Examples of vinyl cyanide monomers include acrylonitrile and methacrylonitrile, with acrylonitrile being preferred. (Meth) acrylic acid ester-based monomers include methyl acrylate, methyl methacrylate, methyl ethacrylate, ethyl acrylate, ethyl methacrylate, ethyl ethacrylate, propyl acrylate, propyl methacrylate, butyl acrylate, methacrylic acid Examples thereof include butyl acid and derivatives thereof.
As the copolymerizable vinyl monomer, one kind or two or more kinds can be used. Examples of such a butadiene-based polymer include polybutadiene, SBR, NBR and the like.

The method for producing the rubbery polymer (A1) is not particularly limited, and any polymerization method can be adopted.

The method of controlling the particle size of (A1) is not particularly limited, and for example, a rubbery polymer having an extremely small particle size (for example, about 80 nm) obtained by emulsion polymerization is chemically treated with an acid or the like. The particle size can be controlled by a known method such as an agglomeration method or a physical agglomeration method using a homomixer. In addition, there is a method in which the particles are grown to a large particle size and the particle size distribution is improved by allowing the emulsion polymerization to take a long time. Furthermore, in carrying out the emulsion polymerization for obtaining the (A1) rubbery polymer, the weight average particle diameter of the obtained rubbery polymer is adjusted by controlling the addition amount of sodium pyrophosphate added as an electrolyte component. You can also That is, when the amount of sodium pyrophosphate added is large, the weight average particle diameter of the obtained rubbery polymer is small, and when it is small, the polymerization average particle diameter is large. Further, the gelation rate can be adjusted by a crossing agent.

As the vinyl cyanide monomer (A2),
Examples thereof include acrylonitrile and methacrylonitrile, and acrylonitrile is particularly preferable. (A2) is 1
One kind or two or more kinds can be used.

The amount of (A2) is 25 to 4 based on the total amount of the monomers (A2) to (A4) used in the graft polymerization.
It is 0% by weight. If (A2) is less than 25% by weight, sufficient chemical resistance cannot be obtained, and if it exceeds 40% by weight, thermal stability is poor, and the heat during molding tends to cause discoloration of the molded product.

Examples of the aromatic vinyl monomer (A3) include styrene, α-methylstyrene, o-, m- or p-methylstyrene, 2,4-dimethylstyrene, p-ethylstyrene and pt-butyl. Styrene, vinyl xylene,
Examples thereof include monochlorostyrene, dichlorostyrene, monobromostyrene, dibromostyrene, fluorostyrene, vinylnaphthalene, and the like, and styrene and α-methylstyrene are particularly preferable. (A3) can use 1 type (s) or 2 or more types.

The amount of (A3) is 60 to 7 based on the total amount of the monomers (A2) to (A4) used in the graft polymerization.
It is 5% by weight. If (A3) is less than 60% by weight, the required thermal stability cannot be obtained, and if it exceeds 75% by weight, the required chemical resistance cannot be obtained.

In the present invention, (A2) and (A3)
In addition to the above, a monomer (A4) copolymerizable with these can be used for graft polymerization, if necessary, within a range not impairing the object of the present invention. Such monomers include unsaturated carboxylic acids such as acrylic acid and methacrylic acid; methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, Pentyl (meth) acrylate, hexyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, decyl (meth) acrylate, dodecyl (meth) acrylate, octadecyl (meth) acrylate , Cyclohexyl (meth) acrylate, benzyl (meth) acrylate, phenyl (meth) acrylate, dimethylaminoethyl (meth) acrylate,
Unsaturated carboxylic acid esters such as diethylaminoethyl (meth) acrylate; unsaturated dicarboxylic acid anhydrides such as maleic anhydride, itaconic anhydride, citraconic anhydride; maleimide, N-methylmaleimide, N-ethylmaleimide , N-butylmaleimide, N-cyclohexylmaleimide, N-phenylmaleimide, N- (2-
Examples thereof include imide compounds of unsaturated dicarboxylic acids such as methylphenyl) maleimide and N- (2-chlorophenyl) maleimide. Among these monomers, methyl acrylate is preferable as the unsaturated carboxylic acid ester, maleic anhydride is preferable as the unsaturated dicarboxylic acid anhydride, and N-phenylmaleimide is preferable as the imide compound. In order to improve the heat resistance of the thermoplastic resin composition, it is preferable to blend a maleimide compound as a part or all of these monomers. (A4) is
One kind or two or more kinds can be used.

The amount of (A4) is 0 to 20% by weight based on the total amount of (A2) to (A4) used for graft polymerization. If the amount of (A4) exceeds 20% by weight, (A4)
Depending on the type of 4), mechanical properties, particularly impact resistance are impaired.

As the graft polymerization method for forming (A), known polymerization methods such as bulk polymerization, solution polymerization, bulk suspension polymerization, suspension polymerization and emulsion polymerization can be used.
As a polymerization initiator, an organic hydroperoxide such as cumene hydroperoxide, diisopropylbenzene hydroperoxide or p-menthane hydroperoxide,
Redox system in combination with a reducing agent represented by a formulation containing sugar and pyrophosphate, a formulation containing sulfoxylate, etc .; an organic peroxide such as benzoyl peroxide, lauroyl peroxide; azo such as azobisisobutyronitrile Examples thereof include compounds, and redox systems are preferable. It can be added all at once or continuously to the system.

As the form of the (A) graft polymer used in the present invention, the (A1) rubbery polymer in the (A) graft polymer is (A2) vinyl cyanide monomer, (A)
It is preferable to have an occlusion structure in which at least a part of 3) an aromatic vinyl monomer and / or (A4) a monomer copolymerizable therewith, a homopolymer or a copolymer is included. To obtain such a structure, (A1)
The rubber-like polymer and the monomer to be graft-polymerized thereto are mixed and allowed to stand to impregnate the monomer (A1) with the monomer, and the monomer-impregnated rubber thus obtained. It is obtained by graft-polymerizing a vinyl-based monomer to a polymer.

For example, first, a rubbery polymer produced by emulsion polymerization is charged into a reactor equipped with a stirring blade and a jacket, and then a part of a vinyl-based monomer to be graft-polymerized is collectively or collectively. It is continuously added dropwise and left at 40 to 70 ° C. for 5 to 60 minutes while stirring, and then the initiator and the remaining monomer are added. As a result, the initially added monomer is impregnated in the rubber-like polymer and polymerized in the rubber-like polymer at the same time as the graft polymerization to be a homopolymer or a copolymer.

As the monomer forming the occlusion structure polymer, the same monomer as the monomer to be graft-polymerized with the rubbery polymer can be used, and preferably (A3).
Aromatic vinyl monomers and / or (A2) vinyl cyanide monomers, particularly preferably (A3) aromatic vinyl monomers are used. By using the (A3) aromatic vinyl monomer, transparency and impact resistance are improved.

The average particle size of the (A1) diene rubbery polymer particles present in the (A) graft copolymerization is 2
The range of 50 to 350 nm is preferable, and the range of 270 to 340 nm is more preferable. As a result, the effect of improving the impact resistance and chemical resistance of the resin composition becomes remarkable, and excellent gloss is obtained.

Further, it is preferable that not only the particle size but also the distribution of the (A1) diene rubbery polymer in the above (A) is controlled. That is, the (A1) diene rubber polymer in (A) has a cumulative particle diameter fraction of less than 250 nm of 10% by weight or less and a cumulative particle diameter fraction of more than 350 nm of 15% by weight or less. Preferably 25
If the cumulative weight fraction of particle size of less than 0 nm is 5% by weight or less,
It is more preferable that the cumulative weight fraction of particles having a diameter of more than 0 nm is 10% by weight or less. As a result, the effect of improving the impact resistance and chemical resistance of the resin composition becomes extremely remarkable. The particle size distribution is not necessarily monomodal and may be multimodal within the above range, but is preferably monomodal from the viewpoint of production efficiency and the like.

The particle size and distribution of the (A1) diene rubbery polymer in (A) may be controlled in the polymerization step for synthesizing (A1) or the subsequent treatment step as described above. In addition, it is possible to adjust the grain size by forming the occlusion structure as described above in the graft copolymerization step.

The blending amount of the component (A) in the resin composition is
It is 20 to 60 parts by weight, preferably 25 to 55 parts by weight, and more preferably 30 to 50 parts by weight, based on 100 parts by weight of the total amount of the components (A) and (B). (A)
If the amount of the component is less than 20 parts by weight, sufficient impact resistance, chemical resistance and thermal stability cannot be obtained, and if it exceeds 60 parts by weight, the transparency becomes poor.

The component (B) used in the resin composition of the present invention includes (B1), (B2) vinyl cyanide monomer, and (B).
3) Aromatic vinyl monomer and, if necessary, (B
4) A hard copolymer obtained by copolymerizing another monomer copolymerizable with these monomers. Among these monomers, (B2), (B3) and (B4) used as necessary are the same monomers as (A4) except corresponding (A2), (A3) and methyl methacrylate. Examples of the monomer include (B2) as acrylonitrile and (B2).
As 3), styrene and α-methylstyrene are particularly preferable. (B4) is preferably methyl acrylate, ethyl acrylate or N-phenylmaleimide, although it varies depending on the purpose of blending. These (B2) to (B
As for 4), 1 type (s) or 2 or more types can be used, respectively.

In addition, a vinyl monomer having a functional group such as an epoxy group, a hydroxyl group or an amide group may be used as (B4) if necessary.

The compounding ratio of (B) and the monomers used for the synthesis of the hard polymer is 45 to 90% by weight, preferably (B1), based on the total amount of the monomers forming (B). 45-7
0% by weight; (B2) 5 to 50% by weight, preferably 15
-40% by weight; (B3) is 5-50% by weight, preferably 15-40% by weight. As a result, a thermoplastic resin having a good balance of thermal stability, impact resistance and chemical resistance can be obtained. It is also used as needed (B
4) is 0 to 30% by weight, preferably 0 to 20% by weight.

The method for producing the (B) hard polymer is not particularly limited, and known polymerization methods such as bulk polymerization, solution polymerization, bulk suspension polymerization, suspension polymerization and emulsion polymerization can be used.

The blending amount of the component (B) in the resin composition is
It is 40 to 80 parts by weight, preferably 45 to 75 parts by weight, and more preferably 50 to 70 parts by weight, based on 100 parts by weight of the total amount of the components (A) and (B). (B)
If the amount of the component is less than 40 parts by weight, the transparency and gloss will deteriorate, and
If it exceeds 0 parts by weight, sufficient impact resistance, chemical resistance and thermal stability cannot be obtained.

Further, a characteristic of the present invention is that
That is, the methacrylic resin (C) having a specific composition range is added to the resin composition. The component (C) is polymethyl methacrylate, or up to 7% by weight based on (C),
It is preferably a copolymer of methyl acrylate and the remaining methyl methacrylate up to 4% by weight, and more preferably polymethyl methacrylate. If the amount of methyl acrylate in the monomer forming the component (C) exceeds 7% by weight, the chemical resistance decreases. By blending such a component (C), it is possible to obtain a resin composition having excellent translucency, impact resistance and chemical resistance.

The compounding amount of the component (C) in the resin composition is
The total amount of the components (A) and (B) is 1 to 10 parts by weight, preferably 1 to 5 parts by weight, based on 100 parts by weight. If it is less than 1 part by weight, the effect of improving thermal stability cannot be obtained, and if it exceeds 10 parts by weight, impact resistance and chemical resistance are deteriorated.

Various additives such as dyes, lubricants, antioxidants, ultraviolet absorbers and antistatic agents can be added to the thermoplastic resin composition of the present invention within the range not impairing the features of the present invention. . Further, if necessary, a reinforcing agent, a filler, a pigment or the like may be added.

The resin composition of the present invention is prepared by mixing the components (A) to (C) and the additives to be added as necessary by a conventional method, for example, using an extruder, a Banbury mixer or the like. Can be prepared. Also, 180-2
Pellets of the resin composition can be prepared by heating the mixture at 60 ° C. and passing it through an extruder and mixing while melting.

The resin composition of the present invention preferably has a total light transmittance of 40 to 100%, more preferably 60 to 100% when formed into a flat plate having a thickness of 3.2 mm.

Injection molding using the resin composition of the present invention,
A molded product can be obtained by any molding method such as blow molding, extrusion molding, profile extrusion molding, or vacuum extrusion and pressure molding after extrusion into a sheet.

[0041]

EXAMPLES The present invention will be described more specifically below with reference to synthesis examples and examples. The present invention is not limited to these examples. In the following examples, "part" means "part by weight", "%" in composition, concentration and the like means "% by weight". The particle size of the rubbery polymer is Microtrac Mo
Del: 9230UPA (manufactured by Nikkiso Co., Ltd.) was used to determine by the dynamic light scattering method. The values obtained are the weight average particle size, the particle size distribution, and the cumulative weight distribution of the particle size distributions. The weight average molecular weight of the hard polymer (B) was calculated by the standard polystyrene conversion method using GPC manufactured by Tosoh Corporation.

Synthesis Example 1: Synthesis of Graft Copolymer (a-1) According to the formulation shown in Table 1, a rubber-containing graft copolymer a-1 was synthesized by an emulsion polymerization method.

[0043]

[Table 1]

That is, the amount of distilled water shown in Table 1, disproportionated potassium rosinate, potassium hydroxide, polybutadiene latex, acrylonitrile, was added to the autoclave.
Charge styrene and t-dodecyl mercaptan, 6
After heating to 0 ° C, ferrous sulfate, sodium pyrophosphate, crystalline glucose and cumene hydroperoxide were added to 2
Add continuously over time, then raise to 70 ° C and
The temperature was maintained for that time to complete the polymerization reaction. An antioxidant was added to the latex obtained by this reaction, then coagulated with sulfuric acid, thoroughly washed with water, and dried to obtain a graft copolymer (a-1).

Synthesis Example 2: Synthesis of Graft Copolymer (a-2) Graft copolymer a was produced in the same manner as in Synthesis Example 1 except that the amount of acrylonitrile was changed to 19 parts and the amount of styrene was changed to 31 parts. -2 was obtained.

Synthesis Example 3: 13 parts of acrylonitrile and 22 parts of styrene as synthetic monomers of the graft copolymer (a-3)
A graft copolymer a-3 was obtained in the same manner as in Synthesis Example 1 except that 1 part and 15 parts of methyl methacrylate were used.

Synthesis Example 4: Synthesis of Graft Polymer (a-4) A graft copolymer a-4 was obtained in the same manner as in Synthesis Example 1 except that the rubbery polymer shown in Table 3 was used.

Synthesis Example 5: Synthesis of Graft Copolymer (a-5) As shown in Table 2, raw materials and the like are charged into an autoclave in two steps, and a rubber-containing graft having an occlusion structure is obtained by emulsion polymerization. A copolymer was obtained.

[0049]

[Table 2]

That is, the substances of the first stage shown in Table 2 were charged in an autoclave, heated to 60 ° C., and then left for 90 minutes. After confirming that the reaction rate reached 70% or more, acrylonitrile, styrene, potassium disproportionated rosinate and potassium hydroxide among the substances in the second stage shown in Table 2 were charged. Ferrous sulfate, sodium pyrophosphate, crystalline glucose and cumene hydroperoxide were then added continuously over 100 minutes. Then, the temperature was raised to 70 ° C. and maintained at that temperature for 1 hour to complete the polymerization reaction. The polymer obtained by this reaction is solidified with sulfuric acid, washed thoroughly with water, and then dried to obtain the graft copolymer a-
Got 5.

Synthesis Example 6: Synthesis of Graft Copolymer (a-6) As a monomer charged in the first step, a mixture of 2 parts of acrylonitrile and 8 parts of styrene was used instead of 10 parts of styrene. Graft copolymer a-6 was obtained in the same manner as in Synthesis example 5.

Synthesis Example 7: Synthesis of graft copolymer (a-7) Synthesis was carried out in the same manner as in Synthesis Example 1 except that the rubbery polymer shown in Table 3 was used.

Synthesis Example 8: Synthesis of Graft Copolymer (a-8) Graft copolymer a-8 was obtained in the same manner as in Synthesis Example 5 except that the rubbery polymer shown in Table 3 was used. .

Synthesis Example 9: Synthesis of graft polymer (a-9) (for comparison) Graft copolymerization for comparison was carried out in the same manner as in Synthesis Example 1 except that 10 parts of acrylonitrile and 40 parts of styrene were used. Combined a-9 was obtained.

Graft copolymer a- obtained in Synthesis Examples 1 to 9
1 to a-9, obtained from the raw material composition (A1) to
Table 3 shows the compounding ratio of (A4) and the proportion of the vinyl cyanide compound (A2) in all the monomers. Further, the weight average particle diameter of the rubbery polymer (A1) in the graft copolymer,
And less than 250 nm and 350 in the rubbery polymer
Table 3 shows the proportion of particles having a particle size exceeding nm.

[0056]

[Table 3]

Synthesis of Hard Polymer (b-1) Synthesis Example 10: 120 parts of water, 0.5 part of polyvinyl alcohol, 0.3 part of azobisisobutylnitrile and 0.3 part of t-dodecyl mercaptan were placed in a reactor substituted with nitrogen. After charging 5 parts, a monomer mixture consisting of 50 parts of methyl methacrylate, 20 parts of acrylonitrile and 30 parts of styrene was added and sealed, and after heating to a temperature of 60 ° C. for 5 hours, 120 ° C.
The temperature was raised to 2, and the reaction was carried out at this temperature for 2 hours. Then, 12
The hard polymer (a-1) was obtained by removing unreacted monomers at 0 ° C. for 2 hours. Conversion rate is 9
6% and the weight average molecular weight was 130,000.

Synthesis Example 11: Synthesis of hard polymer (b-2), except that a mixture of 60 parts of methyl methacrylate, 10 parts of acrylonitrile, 25 parts of styrene and 5 parts of methyl acrylate was used as the monomer mixture. A hard polymer was obtained in the same manner as in Synthesis Example 10. The conversion rate was 95% and the weight average molecular weight was 124,000.

Synthesis Example 12: Synthesis of hard polymer (b-3) As a monomer mixture, 70 parts of methyl methacrylate, 6 parts of acrylonitrile, 9 parts of styrene, 1 part of α-methylstyrene.
A hard polymer b-3 was synthesized in the same manner as in Synthesis Example 10 except that a mixture of 0 part and 5 parts of N-phenylmaleimide was used. Conversion rate is 94%, weight average molecular weight is 116,0
It was 00.

Synthesis Example 13: Synthesis of hard polymer (b-4), except that a mixture of 50 parts of methyl methacrylate, 10 parts of acrylonitrile, 30 parts of styrene and 8 parts of N-phenylmaleimide was used as the monomer mixture. A hard polymer b-4 was obtained in the same manner as in Synthesis Example 10. Conversion rate is 93
%, And the weight average molecular weight was 126,000.

Synthesis Example 14: Synthesis of hard polymer (b-5) (for comparison) Comparative Example 10 was repeated except that a mixture of 25 parts of acrylonitrile and 75 parts of styrene was used as a monomer mixture. To obtain a hard polymer b-5. Conversion rate is 9
5% and the weight average molecular weight was 125,000.

Examples 1 to 11 and Comparative Examples 1 to 7, as the component (A), the graft copolymer a obtained in Synthesis Examples 1 to 9
-1 to a-9 were used, and as the component (B), Synthesis Examples 10 to 10
Using the hard polymers b-1 to b-5 obtained in 14,
As the component (C), a copolymer c-1 containing 97% by weight of methyl methacrylate and 3% by weight of methyl acrylate was used. These components were blended in the blending ratio shown in Table 4, 0.5 parts of ethylene oxide / propylene oxide copolymer was further added as a lubricant, and the components were mixed until uniform,
At a temperature of 220 ° C., the mixture was melt-mixed with a twin-screw extruder (TEX-44, Japan Steel Works, Ltd., trade name) to prepare pellets of the thermoplastic resin composition.

Using the pellets thus obtained, a test piece having a shape defined by each of the following evaluation methods was prepared at a temperature of 240 ° C. by a 4 ounce injection molding machine (manufactured by Japan Steel Works, Ltd.). , Manufactured by injection molding.

Using the test pieces thus obtained, the following evaluations were carried out.

Charpy impact strength ISO-179 / 1e
Charpy impact strength was measured based on A at 23 ° C.

Chemical resistance (critical strain) A strip-shaped test piece having a shape of 150 × 10 × 2 mm prepared by injection molding was fixed along a bending home method test jig, and then a chemical solution was applied to the test piece. 4 at a temperature of 23 ° C
After leaving for 8 hours, the presence or absence of crazes and cracks was visually observed, and the critical strain (%) was determined from the curvature of the test jig. As the chemicals, the following commercially available detergents were used as undiluted solutions. Toilet Magic Rin (Kao Corporation, trade name) Strong Look (Lion Co., trade name) Powers (ST Chemical Co., trade name)

Total light transmittance Using a test piece having a thickness of 3 mm, a reflection / transmittance meter HR-100
(Manufactured by Murakami Color Research Laboratory Co., Ltd.).

Using a heat-stable injection molding machine, 100 × 100 × 2 mm test pieces were prepared at a molding temperature of 280 ° C. A test piece that was molded without staying in the molding machine and 2 pieces inside the molding machine.
The difference in hue after molding from the test piece that was molded by allowing it to stay for 0 minute was measured as the color difference (ΔE) between the two. (Colorimeter: CM-508d (trade name of Minolta Co., Ltd.)

The results of these evaluations are shown in Table 4.

[0070]

[Table 4]

Considering from the evaluation results shown in Table 4, the following is clear. (1) The thermoplastic resin compositions of the present invention prepared in Examples 1 to 11 have transparency, extremely good impact resistance and chemical resistance, and have no discoloration due to retention during molding, Excellent molded products were obtained. (2) When the graft copolymer (A) in which the particle diameter of the rubber polymer (A1) is controlled as in Examples 3, 6 and 7 is used, a molded article having particularly excellent impact resistance and transparency is obtained. was gotten. (3) As in Examples 4, 5 and 7, (A) the graft copolymer was added to (A2) to (A) during (A1) rubbery polymerization.
When the structure containing the homopolymer or copolymer of 4) is adopted, impact resistance and transparency are further improved. (4) As in Comparative Examples 1 and 2, the thermal stability was poor unless the methacrylic resin (C) was blended. On the other hand, as in Comparative Example 6, when the amount of the (C) methacrylic resin is large,
A molded product having good impact resistance and chemical resistance could not be obtained. (5) As in Comparative Example 3, when the ratio of the vinyl cyanide monomer (A2) in the grafting monomer that forms the graft copolymer (A) is less than 25%, good impact resistance is obtained. Therefore, a molded product having chemical resistance could not be obtained. (6) As in Comparative Examples 4 and 5, (A1) in (A)
When the content of the graft copolymer was outside the range of 20 to 90 parts, good impact resistance and chemical resistance could not be satisfied. (7) When a copolymer of acrylonitrile and styrene was used instead of (B) as in Comparative Example 7, the chemical resistance was remarkably reduced.

[0072]

INDUSTRIAL APPLICABILITY The thermoplastic resin composition of the present invention has semitransparency or transparency and is excellent in impact resistance, and particularly has a remarkable effect in chemical resistance, and further has improved thermal stability. It was impossible to reach with the conventional styrene resin,
It is an excellent molding material.

Molded articles using the thermoplastic resin composition of the present invention are transparent or translucent applications such as casings of OA equipment, washing machines, sanitary products and their cases that require impact resistance and chemical resistance. It is extremely useful as a resin material, and its industrial value is extremely large.

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 4F071 AA12X AA22X AA33X AA34X                       AA35X AA76 AA77 AF02                       AF23 AF30 AF43 BA01 BB05                       BC01                 4J002 BC02X BC06X BC07X BG05Y                       BG06X BG06Y BG10X BN13W                       BN14W GB00 GC00 GQ00

Claims (4)

[Claims] 1. (A) (A1) a diene rubbery polymer,
20 to 90% by weight based on (A); (A2) vinyl cyanide monomer, 25 to 40% by weight based on the total amount of (A2) to (A4); (A3) aromatic vinyl A monomer, 60 to 75% by weight based on the total amount of (A2) to (A4); and, if necessary, (A4) another monomer copolymerizable with these monomers,
A monomer mixture consisting of 0 to 20% by weight based on the total amount of (A2) to (A4), and 10 to 80 based on (A).
20% by weight of a graft copolymer obtained by graft-polymerizing 20% by weight, the total amount of (A) and (B) being 100 parts by weight.
To 60 parts by weight; (B) (B1) methyl methacrylate, 45 to 90% by weight based on (B); (B2) vinyl cyanide monomer, 5 based on (B)
50 wt%; (B3) aromatic vinyl monomer, 5 based on (B)
50% by weight; and, if necessary, (B4) another monomer copolymerizable with these monomers,
A hard polymer obtained by copolymerizing 0 to 30% by weight based on (B), 40 to 80 parts by weight based on 100 parts by weight of the total amount of (A) and (B); and (C) polymethacryl The total amount of methacrylic resin (A) and (B), which is a copolymer of methyl acrylate or methyl acrylate up to 7% by weight based on (C) and the remaining methyl acrylate, is 100 parts by weight. A thermoplastic resin composition comprising 10 to 10 parts by weight. 2. The (A1) diene-based rubbery polymer,
The average particle diameter is 250 to 350 nm, and in the cumulative particle diameter weight fraction, less than 250 nm is 10% by weight or less, and 35
The thermoplastic resin composition according to claim 1, wherein particles exceeding 0 nm are particles of 15% by weight or less. 3. The thermoplastic resin composition according to claim 1, wherein the total light transmittance of a flat plate having a thickness of 3.2 mm is 40 to 100%. 4. A molded product obtained by molding the thermoplastic resin composition according to claim 1.