CN1659227A - Thermoplastic resin composition - Google Patents

Abstract

The invention provides a thermoplastic resin composition excellent in transparency and capable of giving molded articles which are excellent in impact resistance and fabrication quality even when they have thin walls. The thermoplastic resin composition comprises a rubber-modified styrene resin composition comprising 60 to 80 % by mass of a continuous phase made of a styrene/(meth)acrylate copolymer and 40 to 20 % by mass of a dispersed phase made of a graft copolymer obtained by grafting a rubbery elastomer with a styrene/(meth)acrylate copolymer wherein the volume-mean particle diameter of the dispersed phase is 0.3 to 0.6 mum and the weight-average molecular weight (Mw) of the continuous phase and the constituent monomer units thereof satisfy a specific relationship and is characterized by containing 0.005 to 0.05 part by mass of an organopolysiloxane and, if necessary, 0.1 to 2.5 parts by mass of an ester lubricant per 100 parts by mass of the rubber-modified styrene resin composition, X=weight average molecular weight (Mw)***(1)120000<=X<=160000(2).

Description

thermoplastic resin composition

technical field

The present invention relates to a thermoplastic resin composition capable of obtaining a molded article having good transparency and excellent impact resistance and moldability even if it is very thin.

Background technique

Conventionally, a method of obtaining a thermoplastic resin composition excellent in impact resistance and transparency by mixing an MBS-based polymer with a rubber-modified styrene-based polymer is well known (Japanese Patent Publication No. Sho 46-32748) , wherein the MBS polymer is a mixture of two or more monomers selected from styrene, methyl methacrylate and acrylonitrile and butadiene and styrene, or acrylonitrile and butadiene monomers The colloidal polymer latex obtained by emulsion polymerization is obtained by emulsion polymerization. However, these thermoplastic resin compositions have a disadvantage that good transparency cannot be obtained in some cases depending on molding conditions, although impact resistance is indeed good.

In addition, with the thinning of molded products in recent years, there are currently very high demands for high rigidity even if it is thin, and excellent thin formability. As means for solving these problems, Japanese Patent Laid-Open Publication No. 2001-226547 proposes a rubber composed of a continuous phase of a specific styrene-(meth)acrylate copolymer and a dispersed phase of a specific graft copolymer. Modified styrenic resin composition. However, the impact resistance and moldability of an extremely thin molded article are not necessarily sufficient.

In view of the present situation, the present invention provides a thermoplastic resin composition capable of obtaining a molded article having good transparency and excellent impact resistance and molding processability even if it is very thin.

Contents of the invention

In order to solve these problems, the inventors of the present invention conducted intensive studies and found that: using a continuous phase composed of a specific styrene-(meth)acrylate copolymer and a dispersed phase of a specific graft copolymer The thermoplastic resin composition comprising a specific amount of organopolysiloxane contained in the rubber-modified styrene resin composition can solve the above-mentioned problems, and the present invention has been finally completed.

That is, the present invention has the following technical gist:

1. A thermoplastic resin composition, which is a rubber-modified styrenic resin composition, which contains (I) a continuous phase of styrene-(meth)acrylate copolymer in an amount of 60 to 80% by mass, and (II) ) 40-20% by weight of the dispersed phase of the graft copolymer; wherein the styrene-(meth)acrylate copolymer is styrene monomer, (meth)acrylate monomer, and Copolymers of vinyl monomers that can be copolymerized with these monomers; the graft copolymers are grafted from styrene-(meth)acrylate copolymers and colloidal elastomers, and the styrene- The (meth)acrylate-based copolymer is a copolymer of a styrene-based monomer, a (meth)acrylate-based monomer, and a vinyl-based monomer copolymerizable with these monomers as required, and is characterized in that The volume-average particle diameter of dispersed phase is 0.3～0.6 μ m, by the weight-average molecular weight (Mw) of continuous phase (Mw) and its constituting the X of formula (1) obtained by monomer unit in formula (2) scope, and relative to 100 parts by mass of the resin composition contains 0.005 to 0.05 parts by mass of organopolysiloxane,

120000≤X≤160000 (2).

2. The thermoplastic resin composition described in 1 above, wherein the rubber-modified styrene resin composition contains 60 to 70% by mass of the continuous phase of (I) styrene-(meth)acrylate copolymer , and (II) 40-30% by weight of the dispersed phase of the graft copolymer.

3. The thermoplastic resin composition according to 1 or 2 above, which contains 0.1 to 2.5 parts by mass of an ester-based lubricant based on 100 parts by mass of the rubber-modified styrene-based resin composition.

4. The thermoplastic resin composition according to 3 above, wherein the ester-based lubricant is hardened castor oil.

5. The thermoplastic resin composition according to any one of 1 to 4 above, wherein the organopolysiloxane is polydimethylsiloxane.

6. The thermoplastic resin composition according to any one of 1 to 5 above, wherein the continuous phase is a styrene-(meth)acrylate copolymer, wherein the copolymer is a styrene monomer unit 20 A copolymer of -70% by mass, 30-80% by mass of (meth)acrylate-based monomer units, and 0-10% by mass of vinyl-based monomer units copolymerizable with these monomers as needed.

7. The thermoplastic resin composition described in any one of 1 to 5 above, wherein the dispersed phase is composed of 20 to 70 parts by mass of styrene-(meth)acrylate copolymer and 30 to 80 parts by mass of A graft copolymer formed by grafting colloidal elastomers of polybutadiene and/or styrene-butadiene copolymers; the aforementioned styrene-(meth)acrylate copolymers are styrene-based single A copolymer of 20 to 70% by mass of monomer units, 30 to 80% by mass of (meth)acrylate monomer units, and 0 to 10% by mass of vinyl monomer units copolymerizable with these monomers as needed.

8. The thermoplastic resin composition according to any one of 1 to 5 above, wherein the continuous phase is a styrene-(meth)acrylate copolymer; wherein the copolymer is a styrene monomer unit 20 ~70% by mass, 30-80% by mass of (meth)acrylate monomer units, and 0-10% by mass of vinyl monomer units that can be copolymerized with these monomers if necessary; and the dispersed phase It is a colloidal elastomer grafted with 20-70 parts by mass of styrene-(meth)acrylate copolymer and 30-80 parts by mass of polybutadiene and/or styrene-butadiene copolymer The resulting graft copolymer; the above-mentioned styrene-(meth)acrylic acid ester copolymer is 20～70 mass % of styrene monomer unit, 30～80 mass % of (meth) acrylate monomer unit, And a copolymer of 0 to 10% by mass of vinyl monomer units copolymerizable with these monomers used as needed.

Detailed ways

The present invention will be described in detail below. The styrene-(meth)acrylate-based copolymer constituting the continuous phase of the rubber-modified styrene-based resin composition of the present invention is a styrene-based monomer, a (meth)acrylate-based monomer, and a Copolymers of vinyl monomers that can be copolymerized with these monomers.

The graft copolymer constituting the dispersed phase of the rubber-modified styrene resin composition of the present invention is a graft copolymer formed by grafting a styrene-(meth)acrylate copolymer and a colloidal elastomer, The aforementioned styrene-(meth)acrylate-based copolymer is a copolymer of a styrene-based monomer, a (meth)acrylate-based monomer, and, if necessary, a vinyl-based monomer copolymerizable with these monomers.

Styrene, α-methylstyrene, p-methylstyrene, o-methylstyrene, m-methylstyrene are examples of the styrene-based monomer used in the continuous phase and the dispersed phase of the present invention. , ethylstyrene, p-tert-butylstyrene, etc., preferably styrene. These styrene-based monomers may be used alone or in combination of two or more.

The (meth)acrylate-based monomers used in the present invention may, for example, be methacrylates such as methyl methacrylate, ethyl methacrylate, butyl methacrylate, and 2-ethylhexyl methacrylate. ; Methyl acrylate, ethyl acrylate, n-butyl acrylate, 2-methylhexyl acrylate, 2-ethylhexyl acrylate, decyl acrylate and other acrylates. Methyl methacrylate or n-butyl acrylate is preferred, and methyl methacrylate is particularly preferred. These (meth)acrylate monomers may be used alone or in combination of two or more.

Vinyl monomers that can be copolymerized with these monomers as needed include: acrylic acid, methacrylic acid, acrylonitrile, methacrylonitrile, N-phenylmaleimide, N-cyclohexylmaleimide imine etc.

The colloidal elastomer used in the present invention may, for example, be polybutadiene, a styrene-butadiene block copolymer or a styrene-butadiene random copolymer.

The amount of styrene monomer units in the styrene-butadiene block copolymer and the styrene-butadiene random copolymer is preferably at most 60% by mass, particularly preferably at most 25% by mass (excluding 0), This is an ideal amount for obtaining good impact resistance and transparency of the rubber-modified styrenic resin composition.

The rubber-modified styrenic resin composition of the present invention contains a continuous phase of 60 to 80% by mass of styrene-(meth)acrylate copolymer, and a dispersed phase of 40 to 20% by mass of graft copolymer, preferably It is a continuous phase containing 60-70% by weight of styrene-(meth)acrylate copolymer, and a dispersed phase of 40-30% by weight of graft copolymer. If the dispersed phase of the graft copolymer is less than 20% by mass, the impact resistance of the thin molded article will be insufficient, and if it exceeds 40% by mass, the molding processability will be insufficient, which is not preferable.

The mass ratio measurement method of the continuous phase and the dispersed phase is that the rubber-modified styrene resin composition (designated as mass A) is stirred in methyl ethyl ketone (MEK) for 24 hours at a temperature of 23° C. Separate the insoluble component of MEK, the amount of the substance after mass measurement vacuum drying (fixed as quality B), obtain by following formula (3), formula (4):

The volume average particle diameter of the dispersed phase of the graft copolymer is preferably from 0.3 to 0.6 μm, particularly preferably from 0.3 to 0.45 μm. If the volume average particle diameter is less than 0.3 μm, the impact resistance of the thin molded article is insufficient, and if it exceeds 0.6 μm, the transparency will be poor, which is not preferable.

X in the formula (1) obtained from the weight-average molecular weight (Mw) of the continuous phase of the styrene-(meth)acrylate-based copolymer and its constituent units must be within the range of the formula (2). Note that the weight-average molecular weight of the continuous phase described here is the weight-average molecular weight in terms of polystyrene obtained by measuring the MEK soluble content of the aforementioned rubber-modified styrene-based resin composition by gel permeation chromatography (GPC method),

120000≤X≤160000 (2).

If X is less than 120,000, the impact resistance of the thin molded product is insufficient, and if it exceeds 160,000, the formability is insufficient, which is not preferable. Particularly preferably, 12500≤X≤15500.

The amount of each monomer unit of the styrene-(meth)acrylate copolymer constituting the continuous phase is not particularly limited as long as it satisfies the aforementioned conditions, but the styrene monomer unit is preferably 20 to 70% by mass , particularly preferably 20 to 40% by mass, preferably 30 to 80% of (meth)acrylate monomer units, particularly preferably 60 to 80% by mass, and vinyl copolymers that can be copolymerized with these monomers as needed The monomer unit is preferably from 0 to 10% by mass, particularly preferably from 0 to 5% by mass.

The amount of the colloidal elastomer and each monomer unit constituting the graft copolymer of the dispersed phase is not particularly limited as long as it satisfies the aforementioned conditions, but is preferably the amount shown below, that is, 30-80 parts by mass , preferably 50-75 parts by mass, especially preferably 50-70 parts by mass of colloidal elastomer, grafted 20-70 parts by mass, preferably 25-50 parts by mass, especially preferably 30-50 parts by mass Styrene-(meth)acrylate copolymers form graft copolymers, wherein the styrene monomer units contained in the styrene-(meth)acrylate copolymers are preferably 20-70 mass %, especially preferably 20-40% by mass; the contained (meth)acrylate monomer units are preferably 30-80% by mass, particularly preferably 60-80% by mass; The vinyl monomer unit to be copolymerized with these monomers is preferably from 0 to 10% by mass, particularly preferably from 0 to 5% by mass.

The rubber-modified styrene-based resin composition of the present invention can be produced by known techniques such as bulk polymerization, solution polymerization, suspension polymerization, bulk-suspension polymerization, and emulsion polymerization. In addition, both a batch polymerization method and a continuous polymerization method can be employed.

The thermoplastic resin composition of the present invention contains an organopolysiloxane. The organopolysiloxane may, for example, be polydimethylsiloxane, polymethylphenylsiloxane or polydiphenylsiloxane, and polydimethylsiloxane is preferred. Modified organopolysiloxanes in which epoxy groups, amino groups, carboxyl groups, hydroxyl groups, methacrylic groups, etc. have been introduced into the terminals or molecules of the organopolysiloxane as needed can also be used. These organopolysiloxanes may be used alone or in combination of two or more.

In the thermoplastic resin composition of the present invention, the combination of the above-mentioned organopolysiloxane and ester-based lubricants has a relatively good effect on achieving a good balance of transparency, impact resistance, and moldability. Examples of ester-based lubricants include: Fatty polyol esters such as cured castor oil, fatty lower alcohol esters such as butyl stearate, fatty acid polyglycol esters such as polyethylene glycol monostearate, and the like, particularly preferably cured castor oil.

The content of the organopolysiloxane is 0.005 to 0.05 parts by mass, preferably 0.01 to 0.03 parts by mass relative to 100 parts by mass of the rubber-modified styrene resin composition. If it is less than 0.005 parts by mass, the impact resistance of the thin molded article will be insufficient, and if it exceeds 0.05 parts by mass, the transparency will deteriorate, which is not preferable.

The content of the ester-based lubricant is preferably from 0.1 to 2.5 parts by mass, more preferably from 0.5 to 2 parts by mass, based on 100 parts by mass of the rubber-modified styrene resin composition. If it is less than 0.1 parts by mass, the combined use effect of the organopolysiloxane and the ester-based lubricant will be small, and if it exceeds 2.5 parts by mass, the transparency will be greatly reduced.

As long as the performance of the thermoplastic resin composition of the present invention is not impaired, known antioxidants, weather resistance agents, lubricants, plasticizers, colorants, antistatic agents, mineral oils, etc. can be added to the thermoplastic resin composition of the present invention. additive.

The thermoplastic resin composition of the present invention thus obtained can be processed into various molded bodies by methods such as injection molding, compression molding, and extrusion molding for practical use. There are no particular limitations on the blending (mixing) and melt-extruding methods for producing various molded articles using the thermoplastic resin composition of the present invention, and known methods can be used. For example, the raw materials are uniformly mixed in advance with a drum or a Henschel mixer (Henschel mixer: high-speed mixer), and then fed into a single-screw extruder or a twin-screw extruder for melt mixing to prepare pellets for molding. The pellets are molded to produce various molded articles.

Example

The present invention will be described in more detail below using examples, but the present invention is not limited to these examples.

First, the production of the raw material resin will be described.

(1) Manufacture of styrene-(meth)acrylate copolymer

Reference example 1: Styrene-(meth)acrylate copolymer A-1

In an autoclave with a capacity of 250 liters, add 100 kg of pure water, 0.5 g of sodium dodecylbenzenesulfonate, 250 g of calcium phosphate, 23 kg of styrene, 73 kg of methyl methacrylate, 4 kg of acrylonitrile, and then add 100 g of polymer The initiator tert-butyl peroxyisobutyrate and 650 g of t-dodecanethiol were stirred at a rotation speed of 150 rpm to disperse the mixed solution. Then, the mixed solution was heat-polymerized at a temperature of 90° C. for 8 hours, and then heat-polymerized at 130° C. for 2.5 hours. After completion of the reaction, it was washed, dehydrated, and then dried to obtain bead-like styrene-(meth)acrylate copolymer A-1.

Reference example 2: Styrene-(meth)acrylate copolymer A-2

In addition to changing the amount of t-dodecanethiol in Reference Example 1 to 800g, other styrene-(meth)acrylate copolymers A-1 were the same to obtain styrene-(meth)acrylic acid Ester copolymer A-2.

Reference example 3: Styrene-(meth)acrylate copolymer A-3

In addition to changing the amount of t-dodecanethiol in Reference Example 1 to 500g, other styrene-(meth)acrylic acid ester copolymers A-1 were the same to obtain styrene-(meth)acrylic acid Ester copolymer A-3.

Reference example 4: Styrene-(meth)acrylate copolymer A-4

In addition to changing the amount of t-dodecanethiol in Reference Example 1 to 900g, other styrene-(meth)acrylic acid ester copolymers A-1 were the same to obtain styrene-(meth)acrylic acid Ester copolymer A-4.

Reference example 5: Styrene-(meth)acrylate copolymer A-5

In an autoclave with a capacity of 250 liters, add 100 kg of pure water, 0.5 g of sodium dodecylbenzene sulfonate, 250 g of calcium phosphate, 42 kg of styrene, 58 kg of methyl methacrylate, and then add 100 g of polymerization initiator isoperoxide Tert-butyl butyrate and 300 g of t-dodecanethiol were dispersed under stirring at a rotation speed of 150 rpm. Then, the mixed solution was heat-polymerized at a temperature of 90° C. for 8 hours, and then heat-polymerized at 130° C. for 2.5 hours. After completion of the reaction, it was washed, dehydrated, and then dried to obtain bead-shaped styrene-(meth)acrylate copolymer A-5.

Reference Example 6: Styrene-(meth)acrylate-based copolymer A-6

In addition to changing the amount of t-dodecanethiol in Reference Example 5 to 600g, other styrene-(meth)acrylic acid ester copolymers A-5 were the same to obtain styrene-(meth)acrylic acid Ester copolymer A-6.

(2) Manufacture of colloidal elastomer latex

Reference Example 7: Colloidal Elastomer Latex G-1

In an autoclave with a volume of 200 liters, add 56 kg of pure water, 400 g of potassium oleate, 1200 g of potassium roseate, 1.2 kg of potassium carbonate, and 400 g of potassium persulfate, and dissolve them uniformly under stirring. Next, add 400g of t-dodecanethiol and 80kg of butadiene, polymerize at 60°C for 30 hours while stirring, then raise the temperature to 70°C for 30 hours, complete the polymerization, and obtain the colloidal elastomer latex G -1.

Reference Example 8: Colloidal Elastomer Latex G-2

In an autoclave with a volume of 200 liters, add 56 kg of pure water, 400 g of potassium oleate, 1200 g of potassium roseate, 1.2 kg of potassium carbonate, and 400 g of potassium persulfate, and dissolve them uniformly under stirring. Next, add 400g of t-dodecanethiol, 23.6kg of styrene, and 56.4kg of butadiene, polymerize at 60°C for 24 hours while stirring, then raise the temperature to 70°C for 24 hours, complete the polymerization, and obtain Colloidal elastomer latex G-2.

Reference Example 9: Colloidal Elastomer Latex G-3

In an autoclave with a volume of 200 liters, add 64 kg of pure water, 400 g of potassium oleate, 1200 g of potassium roseate, 1.2 kg of potassium carbonate, and 400 g of potassium persulfate, and dissolve them uniformly under stirring. Next, add 400g of t-dodecanethiol, 23.6kg of styrene, and 56.4kg of butadiene, polymerize at 60°C for 16 hours while stirring, and then raise the temperature to 70°C for 12 hours to complete the polymerization and obtain Colloidal elastomer latex G-3.

Reference Example 10: Colloidal Elastomer Latex G-4

In an autoclave with a volume of 200 liters, add 115kg of pure water, 500g of potassium oleate, 75g of potassium pyrophosphate, 1.5g of ferrous sulfate, 2.2g of sodium ethylenediaminetetraacetate, and 22g of diaobai powder, and mix them evenly under stirring. dissolve. Then, add 14.5kg of styrene, 35.5kg of butadiene, 148g of t-dodecanethiol, 30g of divinylbenzene, 96g of diisopropylbenzene hydroperoxide, and carry out 16 at a temperature of 50°C while stirring. After 4 hours of reaction, the polymerization was completed and a colloidal elastomer latex was obtained. 45 g of sodium sulfosuccinate was added to the obtained colloidal elastomer latex, and after sufficient stabilization, 0.2 mass % hydrochloric acid aqueous solution and 2 mass % sodium hydroxide aqueous solution were added from respective nozzles to maintain the pH of the latex at 8 to 9 , the latex was coagulated and hypertrophied, and the colloidal elastomer latex G-4 with a volume average particle diameter of 0.6 μm was obtained.

(3) Manufacture of polymers containing graft copolymers

Reference Example 11: Polymer B-1 containing graft copolymer

Measure 30kg of colloidal elastomer latex G-1 of Reference Example 7 in terms of solid content, transfer to a 200L autoclave, add 90kg of pure water, and heat up to 50°C under nitrogen flow while stirring. A solution formed by dissolving 1.5g of ferrous sulfate, 3g of sodium ethylenediaminetetraacetate, and 100g of carved white powder in 2kg of pure water was added to it, and then 7.5kg of styrene and 22.5kg of methyl methacrylate were added continuously for 6 hours. A solution formed by dispersing a mixture of ester, 60g of t-dodecanethiol, 60g of diisopropylbenzene hydroperoxide, and 450g of potassium oleate in 8kg of pure water. After the addition, the temperature was raised to 70° C., and 30 g of diisopropylbenzene hydroperoxide was added, and left for 2 hours to complete the polymerization.

Add an antioxidant to the obtained emulsion, dilute it with pure water so that the solid content is 15% by mass, then raise the temperature to 70°C, add dilute sulfuric acid to carry out salting out while stimulating stirring, and then raise the temperature to 95°C to solidify , followed by dehydration, water washing, and drying to obtain a powdery polymer B-1 containing a graft copolymer.

Reference Example 12: Polymer B-2 containing graft copolymer

The colloidal elastomer latex G-2 of 30kg reference example 8 is measured according to the conversion of solid components, and moved to a volume in an autoclave of 200L, add 90kg pure water, 1.8kg styrene, 4.2kg methyl methacrylate, while stirring The temperature was raised to 50°C under nitrogen flow. A solution formed by dissolving 1.5g of ferrous sulfate, 3g of sodium ethylenediaminetetraacetate, and 100g of carved white powder in 2kg of pure water was added, and then 10.5kg of styrene and 13.5kg of methyl methacrylate were added continuously for 6 hours. A solution formed by dispersing a mixture of esters, 90 g of t-dodecanethiol, 60 g of dicumyl hydroperoxide, and 450 g of potassium oleate in 8 kg of pure water. After the addition, the temperature was raised to 70° C., and 30 g of diisopropylbenzene hydroperoxide was added, and left for 2 hours to complete the polymerization.

Antioxidant was added to the obtained emulsion, diluted with pure water so that the solid content was 15% by mass, then the temperature was raised to 70°C, and dilute sulfuric acid was added while vigorously stirring to carry out salting out, and then the temperature was raised to 95°C to solidify, Then, it was dehydrated, washed with water, and dried to obtain a powdery graft copolymer-containing polymer B-2.

Reference Example 13: Polymer B-3 containing graft copolymer

Except that the colloidal elastomer latex in Reference Example 12 was replaced by colloidal elastomer G-3, other polymers containing graft copolymers were the same as polymer B-2, and powdered polymers containing graft copolymers were obtained. Object B-3.

Reference Example 14: Polymer B-4 Containing Graft Copolymer

Except that the colloidal elastomer latex in Reference Example 12 was replaced by colloidal elastomer G-4, other polymers containing graft copolymers were the same as polymer B-2, and powdered polymers containing graft copolymers were obtained. Object B-4.

Examples 1-11 and Comparative Examples 1-9

According to the proportion shown in Table 1 and Table 2, the styrene-(meth)acrylate copolymer produced in Reference Examples 1 to 6, the polymer containing graft copolymer produced in Reference Examples 11 to 14, Polydimethylsiloxane (KF-96 manufactured by Shin-Etsu Chemical Co., Ltd.), hardened castor oil (Kao Wax (Kao Wax) 85-P manufactured by Kao Corporation), ethylene bisstearamide ( Kao Co., Ltd. manufactured Kao Wax (Kao Wax) EB-P). Then, after mixing this mixture with a Henschel mixer, it melt-mixed at cylinder temperature 220 degreeC with the twin-screw extruder (Toshiba Machine Co., Ltd. product TEM-35B), and pelletized it. Using the obtained sample pellets, various physical property measurements were carried out according to the following physical property measurement methods. The measurement results are shown in Table 1 and Table 2.

(1) Formability of thin forming

Using a Sumitomo Heavy Industries Co., Ltd. injection molding machine (NEOMAT515/150), under the following conditions 1 and 2, the sample pellets were molded into a square plate with a size of 200 × 200 × 1.5 mm, and the thin-formation was evaluated. formability.

Condition 1: Cylinder temperature 190°C, mold temperature 40°C

Condition 1: Cylinder temperature 200°C, mold temperature 60°C

◎··A molded product with good appearance was obtained under both Condition 1 and Condition 2.

○··A molded article with a good appearance can be obtained under either condition 1 or condition 2.

×··Some molding defects such as poor filling, gas burn, and wave-like flow marks occurred, and a molded article with a good appearance could not be obtained under both Condition 1 and Condition 2.

◎ and ○ were judged as pass.

(2) Impact resistance of thin molded products

Using an injection molding machine (SYCAP165/75) manufactured by Sumitomo Heavy Industries Co., Ltd., the sample pellets were molded at a cylinder temperature of 220°C and a mold temperature of 60°C to form a square of 90×90×1mm. plate test piece. The impact resistance of the thin molded article was evaluated by dropping a hammer with a mass of 50 g and a mass of 100 g from a height of 50 cm using a Dupont type drop weight impact tester.

A··With a hammer with a mass of 100g, the non-destructive rate is above 80%.

B··With a hammer with a mass of 50g, the non-destructive rate is above 80%.

C··The non-destructive rate is less than 80% with a hammer with a mass of 50 g.

A and B are judged to be acceptable.

(3) Transparency (turbidity)

Using the injection molding machine (IS-50EP) manufactured by Toshiba Machine Co., Ltd., under the condition of the cylinder temperature of 220 ° C and the mold temperature of 60 ° C, the sample pellets were formed into a square plate test with a size of 55 × 90 × 3 mm. piece. The haze (unit: %) of the test piece was measured according to ASTM D1003.

The analysis of rubber-modified styrenic resin composition, the rubber that is prepared by mixing the styrene-(meth)acrylate copolymer and the copolymer containing graft copolymer according to the ratio of Table 1 and Table 2 in advance Using the pellets of the modified styrene resin composition, each analysis value was measured according to the following measurement method. Each analysis value is shown in Table 1 and Table 2.

(1) Determination of the mass ratio of continuous phase and dispersed phase

Stir the pre-measured sample particles (determined as quality A) in methyl ethyl ketone (MEK) at a temperature of 23°C for 24 hours, and then use a centrifuge to separate the insoluble components in MEK. After centrifugation, Let stand for 30 minutes. The operating conditions of the centrifuge were as follows.

Temperature: -9°C

Number of revolutions: 20000rpm

Time: 60 minutes

Separate the supernatant and the throw out of the solution through centrifugation, dry the throw out with a vacuum drier, then measure the quality (fixed as quality B), and obtain the continuous phase sum by the following formula (3), formula (4) The mass ratio of the dispersed phase.

(2) Determination of the weight average molecular weight of the continuous phase

The supernatant of the centrifuged solution was fractionated, and methanol was added to precipitate the styrene-(meth)acrylate copolymer (continuous phase). This precipitate was collected and measured under the following GPC measurement conditions.

Device name: SYSTEM-21 Shodex (manufactured by Showa Denko)

Column: connect 3 pieces of PL gel MIXED-B in series

Temperature: 40°C

Detection: Differential Refractive Index

Solvent: THF

Concentration: 2% by mass

Calibration line: made of standard polystyrene (PS) (manufactured by PL Co., Ltd.), and the weight average molecular weight is represented by PS conversion value.

(3) Determination of monomer units constituting the continuous phase

The continuous phase (MEK soluble content) composed of styrene-(meth)acrylate copolymer obtained in the pretreatment of the previous measurement was dissolved in heavy chloroform, and the type), and obtained the constituent monomer units.

(4) Determination of the volume average particle size of the dispersed phase

About 1g of the sample particles was stirred in 100g of N,N-dimethylformamide (DMF) for 24 hours, then added DMF to dilute to reach an appropriate concentration, using a laser diffraction scattering method particle size distribution measuring machine (COULTER company LS230 type), were measured.

(5) The ratio of the constituent unit units of the dispersed phase

Each sample powder of the copolymer containing the graft copolymer produced in Reference Examples 11 to 14 was stirred in methyl ethyl ketone (MEK) at a temperature of 23° C. for 24 hours, and then the powder insoluble in MEK was separated by a centrifuge. Components, left to stand for 30 minutes after centrifugation. The operating conditions of the centrifuge were the same as described above.

The supernatant of the centrifuged solution was taken out, and methanol was added to precipitate the non-grafted styrene-(meth)acrylate copolymer. The precipitate was collected, dissolved in heavy chloroform, and the constituent monomer units were determined using FT-NMR (type FX-90Q manufactured by JEOL Ltd.).

In the copolymers containing graft copolymers produced in Reference Examples 11 to 14, the proportion of monomer units of the styrene-(meth)acrylate copolymer grafted with the colloidal polymer, and the ratio of the monomer units without grafting The ratio of the styrene-(meth)acrylate copolymer grafted can be considered to be the same, so this measured value is regarded as the ratio of the styrene-(meth)acrylate copolymer grafted with the colloidal polymer. The ratio of monomer units.

(6) Determination of colloidal elastomer amount and grafted monomer amount of dispersed phase

The precipitate of the centrifuged solution was recovered by filtration, dried with a vacuum drier, and used as a measurement sample of the dispersed phase. The obtained sample was swelled in heavy chloroform, and the constituent monomer units were determined using FT-NMR (type FX-90Q manufactured by JEOL Ltd.).

From the mass ratio of the constituent monomer units of the styrene-(meth)acrylate copolymer obtained in the measurement of the aforementioned (5) (the ratio of the styrene monomer unit is a, the ratio of the (meth)acrylate unit The ratio of the monomer unit is b. The total amount of the monomer unit is 100) and the mass ratio of the monomer unit of the dispersed phase sample obtained here (the ratio of the butadiene monomer unit is c, the ratio of the styrene monomer The ratio of the unit is d, the ratio of the (meth)acrylate monomer unit is e. The total amount constituting the monomer unit is 100), according to the following formula (5) and formula (6), the amount of colloidal elastomer has been obtained and the amount of grafted monomer,

In addition, for the sample of the precipitate (dispersed phase) pretreated in the above (1), the constituent monomer units were determined by FT-NMR, and all of them coincided with the constituent monomer units obtained above.

The examples of the thermoplastic resin composition of the present invention are very excellent in the molding processability of thin molding, the impact resistance and transparency of thin moldings, and the comparative examples of thermoplastic resin compositions that do not meet the conditions of the present invention In terms of formability of thin molding, impact resistance and transparency of thin moldings, there are always some physical properties that are inferior.

Industrial Applicability

According to the present invention, it is possible to provide a thermoplastic resin composition having excellent transparency, and excellent impact resistance and molding processability even for extremely thin molded articles.

Table 1 implement implement implement implement implement implement implement implement Example implement implement Cooperate Styrene-(meth)acrylate copolymer A-1 (parts by mass) 70 70 70 70 65 65 65 65 A-2 (parts by mass) 60 60 A-5 (parts by mass) 65 Polymers containing graft copolymers B-1 (parts by mass) 30 30 30 30 35 35 40 40 35 35 B-2 (parts by mass) 35 Organopolysiloxane (parts by mass) 0.005 0.015 0.045 0.015 0.015 0.015 0.015 0.015 0.015 0.015 0.015 Solidified castor oil (parts by mass) 0.5 1.5 2 3 Ethylenebisstearamide (parts by mass) 1.5 Analytical value of rubber styrenic resin continuous phase The mass ratio of the continuous phase quality% 73 68 64 70 68 Proportion of constituent monomer units (mass%) MMA 72.6 72.7 72.8 57.5 72.7 St. 23.8 23.8 23.8 42.5 23.8 AN 3.6 3.5 3.4 0 3.5 Weight average molecular weight (Mw) 85000 86000 71000 113000 86000 X value 148000 150000 124000 131000 150000 dispersed phase mass ratio of dispersed phase quality% 27 32 36 30 32 colloidal elastomer parts by mass 55 55 55 58 55 Graft monomer amount parts by mass 45 45 45 42 45 Proportion of constituent monomer units (mass%) MMA 74.8 74.8 74.8 57.8 74.8 St. 25.2 25.2 25.2 42.2 25.2 volume average particle size μm 0.40 0.40 0.40 0.39 0.40 Molded product Formability of thin-formed products ○ ○ ○ ◎ ○ ◎ ○ ◎ ○ ◎ ○ Impact resistance of thin molded products B B B B A A A A A A A Turbidity (%) 1.6 2.0 2.8 2.2 2.2 2.8 2.5 3.5 2.9 4.4 4.9

MMA: methyl methacrylate, St: styrene, AN: acrylonitrile

Table 2 comparative example comparative example comparative example comparative example comparative example comparative example comparative example comparative example comparative example Cooperate Styrene-(meth)acrylate copolymer A-1 (Quality 70 70 80 A-2 (quality 50 A-3 (quality 70 A-4 (quality 60 A-5 (quality 65 65 A-6 (quality 65 Polymers containing graft copolymers B-1 (Quality 30 30 20 50 30 40 B-2 (quality 35 B-3 (quality 35 B-4 (quality 35 Organopolysiloxane (parts by mass) 0 0.1 0.015 0.015 0.015 0.045 0.015 0.015 0.015 rubber modified styrene resin continuous phase The mass ratio of the continuous phase quality% 73 82 55 73 64 70 71 70 Proportion of constituent monomer units (mass%) MMA 72.6 72.6 72.6 72.7 72.5 57.5 57.5 57.3 St. 23.8 23.8 23.9 23.8 24.0 42.5 42.5 42.7 AN 3.6 3.6 3.2 3.5 3.5 0 0 0 Weight average molecular weight (Mw) 85000 85000 72000 101000 60000 111000 114000 81000 X value 148000 148000 126000 177000 104000 129000 133000 94000 dispersed phase mass ratio of dispersed phase quality% 27 18 45 27 36 30 29 30 Amount of colloidal elastomer parts by mass 55 55 55 55 55 58 60 58 Graft monomer amount parts by mass 45 45 45 45 45 42 40 42 Ratio of monomer units St. 25.2 25.2 25.2 25.2 25.2 42.2 41.9 42.6 MMA 74.8 74.8 74.8 74.8 74.8 57.8 58.1 57.4 volume average particle size μm 0.40 0.40 0.40 0.40 0.40 0.25 0.65 0.39 Molded product Formability of thin-formed products ○ ○ ○ x x ◎ ○ x ◎ Impact resistance of thin molded products C B C A B C C B C Turbidity (%) 1.6 5.1 1.5 3.3 3.5 2.3 1.8 4.8 2.8

MMA: methyl methacrylate, St: styrene, AN: acrylonitrile

Claims (8)

1. A thermoplastic resin composition, which is a rubber-modified styrene-based resin composition, which contains (I) 60-80% by mass of a continuous phase of a styrene-(meth)acrylate copolymer, and (II) ) 40-20% by weight of the dispersed phase of the graft copolymer; wherein the styrene-(meth)acrylate copolymer is styrene monomer, (meth)acrylate monomer, and Copolymers of vinyl monomers that can be copolymerized with these monomers; the graft copolymers are grafted from styrene-(meth)acrylate copolymers and colloidal elastomers, and the styrene- The (meth)acrylate-based copolymer is a copolymer of a styrene-based monomer, a (meth)acrylate-based monomer, and a vinyl-based monomer copolymerizable with these monomers as required, and is characterized in that The volume-average particle diameter of dispersed phase is 0.3～0.6 μ m, by the weight-average molecular weight (Mw) of continuous phase and its constituting the X of formula (1) obtained by monomer unit in the scope of formula (2), and relatively 0.005 to 0.05 parts by mass of organopolysiloxane is contained in 100 parts by mass of the resin composition, 120000≤X≤160000 (2). 2. The thermoplastic resin composition according to claim 1, wherein the rubber-modified styrenic resin composition contains (1) a continuous phase of styrene-(meth)acrylate copolymer 60 to 70 % by mass, and (II) 40-30% by weight of the dispersed phase of the graft copolymer. 3. The thermoplastic resin composition according to claim 1 or 2, wherein the ester-based lubricant is contained in an amount of 0.1 to 2.5 parts by mass relative to 100 parts by mass of the rubber-modified styrene-based resin composition. 4. The thermoplastic resin composition according to claim 3, wherein the ester-based lubricant is hardened castor oil. 5. The thermoplastic resin composition according to any one of claims 1 to 4, wherein the organopolysiloxane is polydimethylsiloxane. 6. The thermoplastic resin composition according to any one of claims 1 to 5, wherein the continuous phase is a styrene-(meth)acrylate copolymer, wherein the copolymer is a styrene monomer A copolymer of 20 to 70% by mass of units, 30 to 80% by mass of (meth)acrylate monomer units, and 0 to 10% by mass of vinyl monomer units copolymerizable with these monomers as needed. 7. The thermoplastic resin composition according to any one of claims 1-5, characterized in that the dispersed phase is composed of 20-70 parts by mass of styrene-(meth)acrylate copolymer and 30-80 parts by mass The graft copolymer that the colloidal elastomer grafting of polybutadiene and/or the copolymer of styrene-butadiene by mass part; Copolymerization of 20 to 70% by mass of monomeric units, 30 to 80% by mass of (meth)acrylate monomeric units, and 0 to 10% by mass of vinylic monomeric units that can be copolymerized with these monomers as needed things. 8. The thermoplastic resin composition according to any one of claims 1 to 5, wherein the continuous phase is a styrene-(meth)acrylate copolymer; wherein the copolymer is a styrene monomer A copolymer of 20 to 70% by mass of units, 30 to 80% by mass of (meth)acrylate monomer units, and 0 to 10% by mass of vinyl monomer units copolymerizable with these monomers; and The dispersed phase is a colloidal elastomer composed of 20-70 parts by mass of styrene-(meth)acrylate copolymer and 30-80 parts by mass of polybutadiene and/or styrene-butadiene copolymer A graft copolymer formed by grafting; the above-mentioned styrene-(meth)acrylate copolymer is 20-70% by mass of styrene-based monomer units, 30-80% by mass of (meth)acrylate-based monomer units %, and copolymers of 0 to 10% by mass of vinylic monomer units that can be copolymerized with these monomers as needed.