JPH02274747A - Transparent thermoplastic resin composition - Google Patents

Abstract

PURPOSE:To prepare a transparent thermoplastic resin compsn. with an excellent mar resistance, lubricity, low-temp. impact strength, weather resistance, and thermal shock resistance by compounding an organopolysiloxane having a phenyl group into a specific graft copolymer. CONSTITUTION:0.1 to 5 pts.wt. organopolysiloxane having a phenyl groups is compounded into 100 pts.wt. copolymer compsn. comprising a copolymer of methyl methacrylate with a 1 to 4C alkyl acrylate (A), a copolymer of vinyl cyanide with an arom. vinyl (B), and a graft copolymer comprising 30 to 80wt.% rubberlike polymer grafted with 20 to 70wt.% monomer component comprising vinyl cyanide and the arom. vinyl (C), wherein the ratio of vinyl cyanide to the arom. vinyl in said monomer component is (18:82) to (25:75). In said copolymer compsn., the difference in refractive index between the mixture of A with B and C is 0.005 or lower. Thus is obtd. a transparent thermoplastic resin compsn. excellent in the mar resistance, lubricity, and low-temp. impact strength and useful as a material for molding electrical and automotive parts.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention provides a molding material for the electrical field, automobile field, etc. that is transparent, has excellent scratch resistance and lubricity, and has improved impact resistance at low temperatures. The present invention relates to a thermoplastic resin composition used as a thermoplastic resin composition.

(Prior art) Conventionally, polystyrene resin, acrylonitrile-styrene resin (As resin), polymethyl methacrylate-I resin (PMMA resin), transparent acrylonitrile-butadiene-styrene resin (ABS resin), etc. have been used as transparent resins. has been done.

In recent years, even transparent ABS resins with excellent impact resistance and processability are required to have excellent impact resistance over a wider temperature range, and improvement of resin compositions using organosilicon compounds has been proposed. .

However, little effort has been made to improve impact resistance while maintaining transparency.

For example, Japanese Patent Publication No. 49-29947 describes adding and mixing dimethyl silicone and an aliphatic metal salt to improve impact resistance; however, it does not disclose improvement in impact resistance. However, it is not clear how transparency will be maintained.

In addition, Japanese Patent Publication No. 60-26430 proposes a resin composition for plating that has excellent heat cycle properties using an organosilicon compound and a lubricant, but it does not affect the maintenance of transparency and does not allow plating on the surface. The present invention relates to a resin composition used for coating.

Furthermore, in order to improve impact resistance, JP-A-61-24
No. 1342 and Japanese Unexamined Patent Publication No. 63-161045 disclose the use of organic polysiloxane to improve impact resistance in both parallel and perpendicular directions to the resin flow during processing. Disclosed. However, it only relates to improvement of impact resistance using organic polysiloxane, and there is no description regarding transparency.

JP-A-63-162745 describes that adding a special organic silicone compound is effective in improving impact resistance while maintaining transparency.

However, special organic silicone compounds used to improve impact resistance without impeding transparency are low molecular weight compounds that are too weak to impart impact resistance over a wide temperature range, and organopolysiloxane It has the disadvantage that it does not have the effect of improving scratch resistance and lubricity, which are the characteristics of

(Problem to be Solved by the Invention) A transparent resin composition formed by blending a graft copolymer having a rubber-like polymer as a base may be heated to 80° when a sudden temperature change occurs during molding or in the environment. A change from C to room temperature or a change from room temperature to -30 C often causes undesirable whitening in appearance, changes in color tone, and impairs transparency.

Furthermore, organic polysiloxane compounds have not been blended to improve transparency, surface modification (scratch resistance, lubricity, etc.), impact resistance at low temperatures, and thermal shock resistance.

(Means for Solving the Problems) As a result of intensive studies to solve the above problems, the present inventors blended an organic polysiloxane compound containing a phenyl group into a graft copolymer based on a rubbery polymer. The present inventors have discovered that a resin that is transparent and has excellent surface properties (scratch resistance, lubricity, etc.), low-temperature impact resistance, weather resistance, and thermal shock resistance can be obtained by increasing the temperature of the resin, leading to the present invention.

That is, the present invention comprises: (1) a copolymer of methyl methacrylate and an alkyl acrylate having 1 to 4 carbon atoms (A), (2) a copolymer of vinyl cyanide and aromatic vinyl (B), and (4) a rubbery polymer. Vinyl cyanide and vinyl aromatic are contained in 30 to 80 parts by weight, the total amount is 20 to 70 parts by weight, and the weight ratio of vinyl cyanide to vinyl aromatic is 18:
a graft copolymer (C) graft copolymerized so as to have a ratio of 82 to 25:75, and the total of (A) + (B) + (C) is 100 parts by weight, and For 100 parts by weight of a composition in which the difference between the refractive index of the mixture of components (A) + (B) and the refractive index of component (C) is 0.005 or less, ■ organic polysiloxane (D) containing a phenyl group. is 0.
The present invention relates to a thermoplastic resin composition that is transparent and has excellent impact resistance, and is characterized by containing 1 to 5 parts by weight.

The present invention will be explained in more detail below.

The transparent thermoplastic resin composition of the present invention has excellent heat resistance.
Equipment basically composed of the following components: (A) methyl methacrylate resin, (B) acrylonitrile-styrene copolymer, (C) rubber copolymer, and (D) phenyl group-containing organopolysiloxane. It must be.

■ Component (A) is methyl methacrylate (hereinafter referred to as MM
A) system resin, methyl methacrylate 8
5 to 99% by weight and 1 to 15% by weight of alkyl acrylate having 1 to 4 carbon atoms, particularly 1 to 4 carbon atoms.
The amount of alkyl acrylate is preferably 1 to 5% by weight. 1
If it is less than 5% by weight, the effect on thermal stability is weak;
If it exceeds , heat resistance will be poor.

Examples of the argyl acrylate having 1 to 4 carbon atoms include methyl acrylate, ethyl acrylate, butyl acrylate, and the like.

MMA-based resins are manufactured by known bulk polymerization and solution polymerization.

■ Component (B) is vinyl cyanide 15-40% by weight
and aromatic vinyl in an amount of 85 to 60% by weight. In particular, the ratio of vinyl cyanide to aromatic vinyl is preferably 18 to 25% by weight of vinyl cyanide. If vinyl cyanide is less than 18% by weight, chemical resistance etc. will be poor, and 2
If it exceeds 5% by weight, the range of transparency will be narrow (and moldability will be insufficient) when mixed with component (A).

Examples of vinyl cyanide constituting the copolymer include:
Examples include acrylonitrile and methacrylonitrile. Examples of aromatic vinyl include styrene and α-methylstyrene.

Polymers of vinyl cyanide and aromatic vinyl are produced by known bulk polymerization, solution polymerization, suspension polymerization, and emulsion polymerization.

Preferably, it is produced by solution polymerization.

Component (C) consists of 30 to 80 parts by weight of a rubbery polymer, preferably 30 to 60 parts by weight, vinyl cyanide and aromatic vinyl, in a total of 20 to 70 parts by weight, and vinyl cyanide and aromatic vinyl. The weight ratio of group vinyl is 18:82 to 25:
75.

In particular, the weight ratio of vinyl cyanide to vinyl aromatic is preferably 18 to 25% by weight based on the total amount of vinyl cyanide and aromatic vinyl. If the vinyl cyanide is less than 18, the chemical resistance will be poor.
If it exceeds 25% by weight, when mixed with the above component (A),
The transparent range is narrow and moldability is insufficient.

Examples of vinyl cyanide constituting the copolymer include:
Examples include acrylonitrile and methacrylate trile. Examples of aromatic vinyl include styrene and α-methylstyrene.

Note that the rubbery polymer used in component (C) needs to have elastomer properties in order to improve the impact resistance of the composition of the present invention. One factor that indicates the properties of this elastomer is the glass transition point (Tg).
It is preferable that g is a rubbery polymer having a temperature of -30°C or less.

For example, examples of the polymer having a Tg of -30°C or lower include diene polymers such as polybutadiene, styrene-butadiene rubber, butadiene-isoprene rubber, polyisoprene, alkyl acrylate, and alkyl methacrylate polymers.

Examples of the alkyl acrylate include ethyl acrylate, butyl acrylate, and ethylhexyl acrylate.

Further, like the diene type, a rubbery polymer containing an alkyl acrylate and a comonomer such as butadiene, styrene, acrylonitrile, alkyl methacrylate, or a mixture thereof may be used.

Graft copolymers based on rubbery polymers are produced by graft polymerizing vinyl cyanide, aromatic vinyl, etc. in the presence of rubber in a water-soluble emulsion.

■ The blending ratio of the resin composition is 10 to 65% of component (8).
Parts by weight, preferably 15 to 55 parts by weight, 3 parts by weight of component (B)
0 to 50 parts by weight, preferably 40 to 50 parts by weight, component (
5 to 40 parts by weight, preferably 5 to 35 parts by weight of C), the total of each component (8) to (C) is 100 parts by weight, and a mixture of components (A)'' and (B) They are blended so that the difference between the refractive index and that of component (C) is 0°005 or less.

That is, in order for the molded article of the present invention to exhibit transparency, it is necessary that the difference in refractive index between the mixture of components (A) + (B) and (C) be 0.005 or less. The proportions of each component are determined in consideration of the refractive index.

In order to ensure transparency with such a formulation, the following method is used.

For example, refractive index of component (A): (n25) NA component (A)
Blending amount: 8 parts by weight Refractive index of component (B): (n2S) NB component (B)
Blending amount 2 8 parts by weight Refractive index of component (C): (n2S) NC component (C)
When the formulation M: C is parts by weight, A+B+C=100... By determining the ratio of each component that satisfies the formula (1), a transparent resin can be obtained.

For example, if the amount of component (C) is temporarily set to a predetermined amount,
By determining the ratio of components (A) and (B) from equations (1) and (2), a mixing ratio that ensures transparency can be obtained.

(2) Component (D) is an organic polysiloxane containing a phenyl group, and is a polymer having a repeating unit represented by the following general formula.

(-3i-0-) (In the formula, R1 and R2 represent an alkyl group, an aryl group, and an aralkyl group.) The ratio of phenyl groups is 10 to the organic polysiloxane.
It is mol% or more, preferably 20 to 60 mol%. Further, the preferable range of the refractive index is 1°45 to 1.55.

When the proportion of phenyl groups deviates from this range, transparency deteriorates due to a decrease in compatibility and an increase in the difference between the refractive index of the organic polysiloxane and the refractive index of the resin composition.

Furthermore, if the refractive index ratio deviates from this range, the compatibility decreases, and the difference between the refractive index of the organic polysiloxane and the refractive index of the resin composition increases, resulting in a decrease in transparency.

As the organic polysiloxane, for example, one or more types selected from the group of methylphenyldimethylpolysiloxane and diphenyldimethylpolysiloxane are used.

The viscosity of the organic polysiloxane is not particularly limited, but is 10
~100,000 cps (25°C), preferably 5
It is 0 to 2000 cps. If it is less than 10 cpS, the volatility will be high and the appearance of the molded product will be poor.
If it exceeds cps, mixing with the resin will become non-uniform.

The amount of component (D) added is 0.1 to 5 parts by weight, preferably 0.3 to 2 parts by weight, per 100 parts by weight of the resin composition. If the amount is less than 0.1 part by weight, the lubricating effect of the organic polysiloxane will be reduced, and if it exceeds 5 parts by weight, the organic polysiloxane will bleed onto the surface of the molded article, which is not preferable.

■ The method of blending each component is not particularly limited (
, known techniques such as Henschel mixer, tumbler
The powder and granules are mixed with an extruder, kneader, etc.
The mixture can be mixed by various methods, such as melt-mixing using a mixer, sequentially mixing other components into previously melted components, and directly molding the mixture using an injection molding machine.

The resin composition thus obtained is molded using an extrusion molding machine, an injection molding machine, etc., to obtain a molded product that is transparent and has excellent impact resistance.

In addition, the molding temperature at this time is 250 to 310°C, preferably 260 to 290°C, in order to maintain transparency and to prevent whitening of the molded product and joint seams from being noticeable.
It can be done with

The resin composition of the present invention consists of each of the above-mentioned components, but if necessary, antioxidants such as hindered phenols and phosphorus, ultraviolet absorbers, flame retardants, and plasticizers may be added to the extent that they do not impede transparency. , a lubricant, a stabilizer, an antistatic agent, a dye, a pigment, etc. can be added.

The present invention will be specifically explained by examples, but these are not intended to limit the present invention.

(Example) Reference Example 1 Production of Niger raft copolymer (C-1), Rubber latex 1000 prepared by mixing butadiene rubber latex with an average particle size of 0.15 μm and 0.30 μm in a 1:1 ratio
(40% by weight in terms of solid content) and 1 part of emulsifier disproportionated potassium rosin acid were charged into a polymerization tank, and heated to 70°C in a nitrogen stream while stirring, to 600 parts of butadiene rubber. A mixture of 80 parts of acrylonitrile, 320 parts of styrene, 1.2 parts of cumene hydroperoxide, 1.0 parts of t-dodecyl mercaptan, 1.5 parts of sodium formaldehyde sulfoxylate, and ferrous sulfate (FeSO4H7H20) 0 , 15
500 parts of distilled water in which 0.3 parts of ethylenediaminetetraacetic acid/2Na salt were dissolved was added over 6 hours to conduct polymerization.

After the addition was completed, stirring was continued for another 2 hours to complete the polymerization. The polymerization rate was 95%.

The resulting graft copolymer latex was coagulated with a dilute aqueous sulfuric acid solution, washed, dehydrated, and dried to obtain a white powder graft copolymer ((, -1).

The refractive index (n'') of this polymer was 1.540.

Measurement of refractive index (n25): The refractive index of the polymer was measured using a refractometer after preparing a film. (Measurement temperature 25'c) Reference Example 2 Production of Niger raft copolymer (C-2), 100 parts of rubber latex prepared by mixing butadiene rubber latex with an average particle size of 0.15 μm and 0.30 μm in a ratio of 2:1. A graft copolymer (C-2) was obtained in the same manner as in the production of the graft copolymer (C-1), except that 40% by weight in terms of solid content was used.

The refractive index (n25) of this polymer was 1.539.

Reference Example 3: Measurement of refractive index of each component (n25): In the case of a solid, a solid film was prepared and the refractive index of each component was measured using an Atsube refractometer. In the case of liquids, direct measurements were taken.

(Measurement temperature 25°C) (1) Polymethyl methacrylate-1 system: (A-1) Polymethyl methacrylate Jugetsuji (Methyl acrylate 2% by weight) Intrinsic viscosity [η) = 45 mE/g Refractive index (nlD ')=1.491 (A-2) Polymethyl methacrylate resin (methyl acrylate 4% by weight) Intrinsic viscosity [η] -32m17g Refractive index (n25): 1. 492 (2) Acrylonitrile-styrene system: (I3-1) Acrylonitrile-styrene copolymer (AN/St ratio 20:80) Intrinsic viscosity [η'J=60ml/g Refractive index (n”): 1.575 ( B-2) Acrylonitrile-styrene copolymer (AN/St ratio 23 near 7) Intrinsic viscosity [η) = 0.58 mfl/g Refractive index (n”)
n) :1. 574 (The intrinsic viscosity of the polymer is measured at 30"C in methyl ethyl ketone solvent.) (3) Type of organopolysiloxane: Methylphenyldimethylpolysiloxane, *5H-71
0 (D-1) (manufactured by Tou Silicone Co., Ltd.) Viscosity: 500cs (25°C) Refractive index (n25
): 1.533 *5H-550 (D-2) (manufactured by Tomu Silicone Co., Ltd.) Viscosity: 100cs (25°C) Refractive index (n2
5): 1. 494*5H-556(D-3) (manufactured by Tomu Silicone Co., Ltd.) Viscosity: 20cs (25°C) Refractive index (n2
5): 1. 460 diphenyldimethylpolysiloxane, *KF-54 (D-4) (manufactured by Shin-Etsu Chemical Co., Ltd.) Viscosity: 400cs (25°C) Refractive index (n25
): 1. 505 dimethylpolysiloxane, *5H-200 (D-5) (manufactured by Tomu Silicone Co., Ltd.) Viscosity: 1000cs (25°C) Refractive index (n2
5): 1.403 Example 1 As a polymethyl methacrylate resin, (A-1)
31.3 parts by weight as component B, (B~1) 43.7 parts by weight as component C, ((,-1) 25.0 parts by weight, as component (D-1) 1.0 parts by weight, Pre-mix with a Henschel mixer, then use a screw extruder with an outer diameter of 35 mm, and adjust the cylinder temperature to 150-250.
Melt blending was performed at a C1 die temperature of 200-250°C to form pellets.

Next, each physical property was evaluated using a test piece obtained by injection molding under the following conditions.

Injection molding machine molding conditions Nijilinda temperature, 230 to 290°C Mold temperature, 55°C The physical properties shown in the following examples and comparative examples were measured by the following method.

■Transparency: Total light transmittance and haze were measured according to JIS K-6714.

■Heating deformation temperature: Measured according to JIS K-6871.

■ Izot impact strength: Measured according to the method of ASTM D-256 (kg-cm/cm, notched, thickness 1/4°) while changing the measurement temperature.

■Thermal shock resistance test: After placing the molded product in 80°C warm water and leaving it for 1 hour,
It was placed in a -30°C freezer and left for 1 hour.

Thereafter, the molded product was taken out and left at room temperature for 1 hour, and then the total light transmittance and haze were measured according to JIS K-6714.

■Moldability (flowability): +30 as MFR (melt flow index)
-1130 (g/10m1n; 200°C11C11
It was measured by a method based on O.

■Dynamic friction coefficient Nilast wear test specimen (inner diameter 22.825mm
25. A cylindrical molded piece with a diameter of 650 mm and a length of 20 mm was prepared and measured at 23°C using a thrust abrasion tester using a molded piece of steel and the same resin as mating materials at a load of 1 kg and a rotation speed of 500 rpm.

■Scratch resistance test: Using a conical 50μmR diamond paste, scratches were made at a speed of 50mm/min by changing the vertical load in stages, and the load was displayed when a scratch with a width of 5μm or more was made. .

Examples 2 to 10 Pellets were prepared by using the composition ratios of each component as shown in Table 1, and the following operations were performed in the same manner as in Example 1 to evaluate each physical property, which is shown in Table 1.

Comparative Examples 1 to 3 Pellets were prepared by using the composition ratios of each component as shown in Table 2, and the following operations were performed in the same manner as in Example 1 to evaluate each physical property, which is shown in Table 2.

In addition, in Comparative Example 2, 5H200 (toμ・
(I)-5) manufactured by Silicone Co., Ltd. was used. Furthermore, in Comparative Example 3, bisdiphenylmethylsilylmethylphenylsiloxane (D6) was used as the organic siloxane.

Table 2 (Effects of the Invention) According to the present invention, it is possible to obtain a resin composition that is transparent and has excellent impact resistance, and also has scratch resistance, lubricity, impact resistance at low temperatures, and less whitening of molded products. A thermoplastic resin can be obtained.

(1 other person) Procedural amendment May 24th, 1989

Claims (1)

[Scope of Claims] [1] Copolymer of methyl methacrylate and alkyl acrylate having 1 to 4 carbon atoms (A), [2] Copolymer of vinyl cyanide and aromatic vinyl (B)
), [3] Vinyl cyanide and vinyl aromatic are added to 30 to 80 parts by weight of the rubbery polymer, the total amount of which is 20 to 70 parts by weight, and the weight ratio of vinyl cyanide to vinyl aromatic is 18.
:82 to 25:75, and the total of [4](A)+(B)+(C) is 100 parts by weight. Composition 10 where the difference between the refractive index of the mixture of components (A) + (B) and the refractive index of component (C) is 0.005 or less
[5] Organopolysiloxane containing phenyl group (D) is 0 parts by weight.
．． A thermoplastic resin composition that is transparent and has excellent impact resistance, characterized in that it contains 1 to 5 parts by weight.