JPS62265337A - Vinyl aromatic resin composition - Google Patents

Abstract

PURPOSE:To obtain the title composition excellent in heat resistance, impact resistance and moldability, by dissolving an ethylene/propylene rubber in a mixture containing a vinyl aromatic monomer and an alpha,beta-ethylenically unsaturated acid and polymerizing the solution. CONSTITUTION:3-50pts.wt. ethylene/propylene rubber is dissolved in 100pts.wt. mixture containing 70-97wt% vinyl aromatic monomer (e.g., styrene) and 30-3wt% alpha,beta-ethylenically unsaturated acid [e.g., (meth)acrylic acid], and the solution is polymerized in, e.g., an aqueous suspension at 60-180 deg.C in the presence (absence) of a polymerization initiator. At least 10mol% unsaturated acid groups are neutralized by adding an ionic metal compound (e.g., methanolic solution of sodium methylate) to the reaction mixture to obtain the title composition wherein 5-50wt% soft component particles (particle diameter of 0.3-5mu) formed by grafting the neutralized vinyl aromatic monomer upon 3-50pts.wt. ethylene/propylene rubber are dispersed in a hard phase of 100pts.wt. vinyl aromatic polymer of a weight-average MW of 10,000-500,000.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a vinyl aromatic resin composition, and more specifically, it has excellent impact resistance, heat resistance, moldability, etc., and is used in automobiles, home appliances,
The present invention relates to a composition that can be effectively used as a material for various molded products in the field of office automation (OA) and the like.

[Prior art and problems to be solved by the invention] In general, rubber-containing vinyl aromatic resins such as rubber-containing styrene resins are widely used as molding materials because of their excellent impact resistance and moldability. However, it had the disadvantage of poor heat resistance.

Therefore, as a styrene-based resin with improved heat resistance, a resin made by neutralizing a styrene-unsaturated acid copolymer containing butadiene rubber was proposed in 1 (Japanese Patent Laid-Open No. 48-4'
6671, JP-A-60-106818).

However, these resins have a problem in that the butadiene rubber deteriorates during molding, resulting in a decrease in impact resistance.

The purpose of the present invention is to solve the above-mentioned conventional problems and provide a composition with improved heat resistance without sacrificing the inherent properties of rubber-containing vinyl aromatic resins such as impact resistance. It is something to do.

[Means for Solving the Problems] That is, the present invention provides 70 to 97% by weight of vinyl aromatic III-position and 30 to 3% by weight of α,β-ethylenically unsaturated acid units.
A vinyl aromatic copolymer (hereinafter referred to as "component (A)") with a weight average molecular weight of 10,000 to 500,000, in which 10 mol% or more of its unsaturated acid groups have been neutralized.
Ethylene-propylene rubber (hereinafter referred to as
It is called r'(B) component. ) in a ratio of 3 to 50 parts by weight, the amount of the soft component particles is 5 to 50% by weight of the resin composition, and the soft component particle diameter is 0. The object of the present invention is to provide a vinyl aromatic resin composition characterized in that the particle diameter is 3 to 5 μm.

The vinyl aromatic copolymer which is component (A) in the present invention has 70 to 97% vinyl aromatic units, preferably 8% vinyl aromatic units.
0 to 95% by weight and 3 α,β-ethylenically unsaturated acid units
It consists of 0 to 3% by weight, preferably 20 to 5% by weight. Here α.

When the β-ethylenically unsaturated acid unit exceeds 30%,
Molding processability is reduced, and if it is less than 3% by weight, heat resistance is reduced, which is not preferable. In addition, this component (A) has a weight average molecular weight of 10,000 to 50
50,000, preferably 50,000 to 400,000. Here (A
) If the weight average molecular weight of the component is less than 10,000, the impact resistance will be lowered, while if it exceeds 500,000, the moldability will be lowered, which is not preferable.

Furthermore, component (A) in the present invention has 10 unsaturated acid groups.
At least mol %, preferably at least 25 mol %, more preferably at least 50 mol % is neutralized. Here (A
If the amount of neutralization of the unsaturated acid groups in the vinyl aromatic copolymer (component ) is less than 10 mol %, the heat resistance will be lowered, which is not preferable.

The above component (A) consists of a vinyl aromatic monomer forming a vinyl aromatic unit and an α,β-ethylenically unsaturated acid position.
, β, β-ethylene saturated acid is copolymerized by a known method and then neutralized, or a vinyl aromatic monomer and α,
It can be obtained by copolymerizing a β-ethylenically unsaturated acid metal salt by a known method.

There are various vinyl aromatic monomers forming the vinyl aromatic unit, such as styrene.

α-methylstyrene, 0-methylstyrene, m-methylstyrene, p-methylstyrene, α-ethylstyrene,
Examples include methyl-α-methylstyrene, dimethylstyrene, chlorostyrene, dichlorostyrene, bromstyrene, dibromstyrene, and vinylnaphthalene. Among these, styrene and α-methylstyrene are particularly preferred.

In addition, α, β-ethylenically unsaturated acid units α, β,
Specific examples of β-ethylene saturated acids include acrylic acid, methacrylic acid, and ethacrylic acid.

In addition to ichconic acid, maleic acid, fumaric acid, etc., maleic anhydride, maleic anhydride,
Examples include styrene sulfonic acid. Among these, especially acrylic acid.

Preferred are methacrylic acid, maleic anhydride, and styrene sulfonic acid.

The amount of neutralization of component (A) can be adjusted by reacting the vinyl aromatic copolymer with an ionic metal compound to neutralize unsaturated acid groups.

Here, the reaction between the vinyl aromatic copolymer and the ionic metal compound is not particularly limited as long as the two are in contact with each other and react. For example, when producing component (A), there is a method in which an ionic metal compound is added and reacted in a container before, during or after the polymerization process. Alternatively, there is a method in which a mixture of a vinyl aromatic copolymer and an ionic metal compound is heated and kneaded using an extruder, mixer, roll, etc., and reacted. Furthermore, water or an organic solvent or a mixture thereof '<6? There is a method of reacting a mixture of a vinyl aromatic copolymer and an ionic metal compound in a dissolved or suspended state in Rl by heating as necessary and stirring and mixing.

On the other hand, when copolymerizing a vinyl aromatic monomer and an α,β,β-ethylenically unsaturated acid metal salt, the vinyl aromatic monomer and an α,β,β-ethylene saturated acid metal salt are copolymerized. Adjust the amount of neutralization depending on the composition ratio of salt.

The ionic metal compounds used to adjust the amount of neutralization of component (A) above are the hydroxides, oxides, metal salts, and alcolades of gold m-(one) having a valence of 1 to 3 as shown below. , α, β-ethylenically inert saturated acid metal salts. Here, the monovalent metal ions include Na", K", Li"
, Cs", Ag", and Cu", and divalent metal ions include MB", Ca", and Fe".

Zn”, Be”, Sr”, Ba”, Cu”,
There are ``Sn'', ``Co'', and ``Ni'', as well as ^ff ``'' as trivalent metal ions.

There is pe-++. Hydroxide-oxide; Metal salts such as acetic acid and methacrylic acid; Alcoholades such as methylate and ethylate; Specific examples of α,β-ethylenically inert saturated acid metal salts are as follows. First, as hydroxides, Na0tl, KOII, Mg(Off) 2. C
a(Off) 2+Fe(Ofl)z, Zn(OH)
z, Ba(OH)z, 5n(Off)z, A/
(011)3 etc. are mentioned. Next, as an oxide, N
a2O, KzO5MgO+ Cab, Fed, Zn
Examples include O, Bad, SnO, ^1203, and the like.

In addition, as a metal salt, Na(: l, NaCzH,1
0□.

NazSO4, sodium methacrylate, styrene sulfonate, KCR, KCzlhO□, Kz
SOa, MgCj! z.

Mg(Czl110□)z+ MgSO4, Magnacium Tutaacrylate.

CaC1,2,Ca(C2lltOz) 2+ Ca
5Oa, FeCe 2. Fe(Czl130z
) Z+Fe5Oa, ZnCl1! z, Zn(Cz
l130z)z, ZnSO4, zinc methacrylate,
Zinc stearate, RaC/z, Ba(C2llt
Oz)z.

11asO<, barium stearate, tin stearate, dibutyltin dilaurate, dibutyltin distearate, AlCl3. Aff (SO4) z and others are defeated. Furthermore, alcoholades include sodium methylate, sodium ethylate, and natriuno.

Examples include ferato. Moreover, examples of α,β-ethylenically unsaturated acid salts include sodium methacrylate, zinc methacrylate, magnesium methacrylate, and sodium styrene sulfonate. Among these, alcohol-1. such as sodium methylate and sodium ethylate, and metal salts such as sodium acetate and zinc acetate are preferred.

The vinyl aromatic resin composition of the present invention is as described above (A).
With respect to 100 parts by weight of component, ethylene as component (B)
3 to 50 parts by weight of propylene rubber, preferably 5 to 4 parts by weight
It is blended in a proportion of 0 parts by weight. In the present invention, since ethylene-propylene rubber is particularly used as the rubber, the rubber does not deteriorate during molding and the impact resistance does not decrease. However, if the content of ethylene-propylene rubber is less than 3 parts by weight, there is no effect;
The impact resistance will be reduced. On the other hand, if it is contained in an amount exceeding 50 parts by weight, it is not preferable because the molding processability deteriorates.

The amount of soft component particles in this resin composition is 5 to 50% by weight, preferably 7 to 40% by weight of the resin composition.

If the amount of soft component particles is less than 5% by weight, the impact resistance will be reduced, while if it exceeds 50% by weight,
This is not preferable because the heat resistance will be reduced.

Furthermore, the particle size of the soft component in this rubber is 0.3 to 5 μm.
m, preferably 0.5 to 3 μm. If the soft component particle size is less than 0.3 μm, the impact resistance will be lowered, while if it exceeds 5 μm, the heat resistance and impact resistance will be lowered, which is not preferable. The particle size of this soft component may be adjusted by adjusting the stirring rotation speed, catalyst amount, etc. during polymerization when producing the resin composition.

The ethylene-propylene rubber, which is the component (B) above, is a rubbery copolymer consisting of two components of ethylene-propylene or three components of ethylene-propylene-nonconjugated diene, and in particular, the molar ratio of ethylene and propylene is former:
The ratio of i&-W = 3:t to 1:3 is preferred. Further, as the above-mentioned non-conjugated diene, norbornenes, I''2-shaped diene, digitorum group dienes, etc. are used,
Particularly preferred are 5-ethylidene-2-norbornene and synclopentadiene. The proportion of this non-conjugated diene is preferably 40 or less in terms of iodine value. This ethylene rubber [1 Mooney viscosity of pyrene rubber, (100°
C) is not particularly limited, but 10 to 100, preferably 2
0 to 70 is used.

The vinyl aromatic resin composition of the present invention is as described above, and any known polymerization method can be used as long as the above characteristics are satisfied.

It can be manufactured by applying a kneading method. As a polymerization method, a graft polymerization method generally used to obtain an impact-resistant resin can be applied. Specifically, ■ Ethylene-propylene rubber is dissolved in a vinyl aromatic monomer and an α,β-ethylenically inert saturated acid compound, and 60-150% is dissolved in the presence or absence of a polymerization initiator. Polymerize at °C.
In the so-called bulk polymerization method, partial polymerization is carried out according to the method described in (■) above, and then the polymerization is suspended in water with a concentration of 60-18
So-called bulk-suspension polymerization method in which ethylene-propylene rubber is polymerized at 0°C with vinyl aromatic monomer and α,
6. Dissolved in β-ethylenically inert saturated acid compound and suspended in water in the presence or absence of a polymerization initiator.
The so-called suspension polymerization method, in which polymerization is carried out at 0 to 180°C, ■
In the method (2) above, a so-called solution polymerization method is used in which a solvent is used to reduce the viscosity and facilitate stirring or to facilitate the transfer of the liquid polymer, and the polymerization is carried out at 60-180°C in a diluted state. ■Use latex-like ethylene-propylene rubber and use j! as a polymerization initiator. In an emulsified state using 1fJ1 compound, 40~
Examples include the so-called emulsion polymerization method in which graft polymerization is carried out at 150°C. In addition, the addition of saturated acid for α, β-ethylenically inert compounds may be carried out in the initial stage of polymerization or when the polymerization has progressed to a certain extent, and the entire amount may be added at once, or it may be added in portions and added sequentially. You may. In the composition where polymerization has been completed in this way, a soft component is formed by grafting a vinyl aromatic monomer neutralized to ethylene-propylene rubber into a hard phase of the vinyl aromatic copolymer. are dispersed as particles. In addition to the above method, it can also be produced by producing a vinyl aromatic copolymer in the absence of ethylene-propylene rubber and then kneading the rubber.

The resin composition of the present invention has the above-mentioned constitution, and optionally contains an antioxidant, an ultraviolet absorber, an antistatic agent, a flame retardant, a lubricant, a colorant, and a pigment.

It may also contain additives such as fillers.

〔Effect of the invention〕

The vinyl aromatic resin composition of the present invention as described above has excellent heat resistance.

Moreover, the vinyl aromatic resin (x) composition of the present invention has excellent impact resistance, moldability, etc.

Therefore, the present invention can be effectively used as a material for various molded products in the fields of automobiles, home appliances, OA, etc.

〔Example〕

Next, the present invention will be explained by examples.

Example 1 300 g of styrene was placed in an autoclave with an internal volume of 1 e.
10g methacrylic acid, 30g ethylene-propylene rubber
and benzoyl peroxyl as a polymerization initiator.
After adding 0.2 g and purging with nitrogen, the reaction was carried out at 100°C for 4 hours. The reaction mixture was reprecipitated in n-hexane to obtain a rubber-containing styrene-methacrylic acid copolymer. The conversion rate of the copolymer was 32.3% by weight, and the ratio of styrene units to methacrylic acid j1''L position was 90 times the former and 10 times the latter.

This copolymer is dissolved in a mixture of methyl ethyl ketone (MEK) and methanol (former/latter = 20/3 (volume ratio)), and the star sodium methylate is used to neutralize 100% of the carboxyl groups in the copolymer. A methanol solution of (ionic metal compound) was added to neutralize the mixture, and the mixture was reprecipitated in n-hexane to obtain a composition. Table 1 shows the measurement results of the physical properties of the obtained composition.

Examples 2 to 11 and Comparative Examples 1 to 6 In Example 1, the same operations as in Example 1 were performed except that the conditions shown in Table 1 were used.

The results are shown in Table 1.

Example 12 After neutralizing methacrylic acid with a methanol solution of sodium methylate, the same algae cultivation as in Example 1 was carried out. The results are shown in Table 1.

Example 13 The same operation as in Example 1 was performed except that zinc acetate was used instead of sodium methylate. The results are shown in Table 1.

Example 14 In Example 1, a styrene-methacrylic acid copolymer was obtained which was polymerized and neutralized without using ethylene-propylene rubber. 40 parts by weight of ethylene-propylene rubber was blended with 100 parts by weight of the obtained copolymer and kneaded at 280°C to obtain a resin composition. The results are shown in Table 1.

*1: Type of unsaturated acid unit M A A...Methacrylic acid SS...Styrene sulfonic acid M A n h...Maleic anhydride *2: Amount of unsaturated acid unit (wt%) MP, The vinyl aromatic copolymer was dissolved in a mixed solution of /benzene/methanol = 3/2/1 (volume ratio), and the mixture was measured using Hensen's solution of sodium methoxide using thymol blue as an indicator.

*3: Weight average amount (M w ) A 0.2% by weight solution of vinyl aromatic copolymer was added to CP manufactured by Waters Co., Ltd. using tetrahydrofuran as a medium.
It was determined in terms of polystyrene using C150C.

*4: Neutralization amount Amount of unsaturated acid groups of vinyl aromatic copolymer neutralized with ionic metal compound *5: Type of ethylene-propylene rubber EPR...
Ethylene-propylene rubber (Mooney viscosity ML144 (
100°C) 24° Propylene content 26% by weight 1 Japan Synthetic Rubber (+ candle!!! EP02P) EPDM... Ethylene-propylene-ethylidene norbornene copolymer (knee viscosity ML+-4 (100°C) 4S.

Propylene content 42% by weight, iodine value 269 EP manufactured by Japan Synthetic Rubber US 33) PB...low-cis polybutadiene (Mooney viscosity ML+-4 (100°C) 35° NF35AS manufactured by Asahi Kasei Corporation) *6: Ethylene-propylene The rubber-forming amount of the system rubber is parts by weight based on 100 parts by weight of the vinyl aromatic copolymer *7: Soft component particle amount The resin composition was dissolved in a mixed solution of MEK/methanol = 4/l (volume ratio) and 12,000G.

After centrifuging for 15 minutes and removing the supernatant by decantation, the insoluble matter was reprecipitated in methanol, filtered and dried, and the weight of the insoluble matter was calculated based on the formula below.

*8: Soft component particle size The insoluble matter in *7 above (before being re-precipitated in methanol) was dispersed in MEK, and after spraying it on a collodion membrane covered mesoche using a sprayer, it was measured using a transmission electron microscope. The photograph was taken as I-crystal, and the particle size of about 200 particles was measured. Next, the area average diameter was calculated based on the formula below, and this was defined as the soft component particle diameter.

If the particle size of the i@th particle is di, then the area average diameter = Σdi' /Σdi2 *9: Is it? Strength JIS K 7110 (23°C, with notch)
[1 town, 1 place * 10 = Bikanoto softening point

Claims (1)

[Claims] (1) It consists of 70 to 97% by weight of vinyl aromatic units and 30 to 3% by weight of α,β-ethylenically unsaturated acid units, and 10 mol% or more of the unsaturated acid groups are neutralized. Vinyl aromatic copolymer 1 having a weight average molecular weight of 10,000 to 500,000
00 parts by weight of ethylene-propylene rubber
A resin composition containing soft component particles blended at a ratio of 50 parts by weight, wherein the amount of the soft component particles is 5 to 50% by weight of the resin composition, and the soft component particle diameter is 0.3 to 5 μm.
A vinyl aromatic resin composition characterized in that m.