JPH05279536A - Thermoplastic resin composition of excellent transparency - Google Patents

Abstract

PURPOSE:To provide a thermoplastic resin composition which is inexpensive and has excellent permanent antistatic properties and good transparency by mixing an acrylic resin with a vinyl cyanide/aromatic vinyl copolymer and a polyamide elastomer in a specified ratio. CONSTITUTION:This composition is prepared by adding 0-10 pts.wt. at least one member (E) selected between an organic electrolyte and an inorganic electrolyte to 100 pts.wt. resin composition comprising 1-96wt.% acrylic resin (A), 1-96wt.% vinyl cyanide/aromatic vinyl copolymer (B), 0-30wt.% acid-modified resin (C) and 3-30wt.% polyamideimide elastomer (D). The difference in refractive index between a mixture comprising components A, B and C and component D is 0.02 or below. This composition can be molded by processes usually used for molding thermoplastic resins, such as injection molding, blow molding, vacuum forming, inflation, film extrusion, sheet extrusion, etc.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has excellent permanent antistatic properties, is inexpensive, and has good transparency. For example, it is used for lighting equipment, equipment nameplates, meter covers, electronic products, home electric appliances. , A resin composition suitable as a material capable of preventing electrostatic charge in various parts such as office automation equipment.

[0002]

2. Description of the Related Art Conventionally, typical transparent resins such as acrylic resins and copolymers of styrene and vinyl cyanide (AS resins) have excellent transparency and rigidity. It is widely used as a material for various parts such as. However, acrylic resins and AS resins have a large surface resistivity and are easily charged by friction and the like, so dust and dirt adhere to the appearance, or in electronic parts, an undesirable situation due to static electricity is brought about. It has drawbacks. Therefore, it is desired to develop a material having excellent transparency and antistatic property.

As a method of imparting antistatic properties to the acrylic resin, for example, a method of kneading and mixing a surfactant or attaching it to the surface is well known. The antistatic agent is easily removed by washing with water or rubbing, and it is difficult to impart a permanent antistatic property. As a method for imparting a permanent antistatic property, JP-A-55-36237 and JP-A-63-
Japanese Patent Laid-Open No. 63739 and Japanese Patent Laid-Open No. 62-119256 are disclosed.

Further, as an improved product of high cost and reduced heat resistance, an acrylic resin composed of a polyamide-imide elastomer and an acrylic resin, which has excellent permanent antistatic property, is inexpensive and has excellent transparency. There is a resin composition (Japanese Patent Laid-Open No. 2-255753).

[0005]

Polyamideimide, which is a hard segment of this polyamideimide elastomer, is involved in the heat resistance, strength, hardness and affinity of the elastomer with an acrylic resin. It has been reported that in the acrylic resin composition, the hard content is preferably 35% or less in order to maintain transparency with the acrylic resin. Therefore, the resin composition containing this elastomer tends to have lower strength and rigidity.

[0006]

The present inventor has found that when a polyamideimide elastomer having a high hard segment content and an acrylic resin or an AS resin are melt-mixed, the refractive index of the polyamideimide elastomer, the acrylic resin and A
It has been found that an antistatic resin composition having excellent transparency and rigidity can be obtained by blending the S-based resin so that the difference in the refractive index obtained when melt-mixed is 0.02 or less. The present invention has been completed based on the findings. It has also been found that by acid-modifying a part of this acrylic resin, the releasability and HAZE are improved and a resin having higher transparency is obtained.

That is, the present invention comprises (A) 1 to 96% by weight of an acrylic resin, (B) 1 to 96% by weight of a copolymer of vinyl cyanide and aromatic vinyl, and (C) acid modification. Resin composition 100 containing 0 to 30% acrylic resin and 3 to 30 parts by weight of (D) polyamideimide elastomer
An antistatic resin composition obtained by blending 0 to 10 parts by weight of at least one selected from (E) an organic electrolyte and an inorganic electrolyte with respect to parts by weight, and (A) +
A thermoplastic resin composition which is transparent and has excellent antistatic properties, characterized in that the difference between the refractive index of the mixture of (B) + (C) and the refractive index of the component (D) is 0.02 or less.

The present invention will be described in detail below. Examples of the acrylic resin used as the component (A) in the composition of the present invention include polymethyl methacrylate (MMA).
Resin), and a polymer formed by copolymerizing 60% by weight or more of methyl methacrylate with 40% by weight or less of another copolymerized vinyl monomer, and these may be used alone.
You may combine 2 or more types. Examples of the copolymerizable vinyl monomer include butadiene, isoprene, chloroprene, alkyl methacrylate, alkyl acrylate, styrene, α-methylstyrene, acrylonitrile, acrylic acid, methacrylic acid, fumaric acid, maleic acid and itaconic acid. Is mentioned.

In the present invention, the copolymer of vinyl cyanide and aromatic vinyl used as the component (B) comprises 15 to 40% by weight of vinyl cyanide and 85 to 60% by weight of aromatic vinyl. In particular, the ratio of vinyl cyanide and aromatic vinyl is preferably 18 to 25% by weight of vinyl cyanide. 18% by weight of vinyl cyanide
If it is less than 25% by weight or more than 25% by weight, it is difficult to obtain a homogeneous transparent feeling when mixed with the component (A). Examples of vinyl cyanide constituting the copolymer include acrylonitrile and methacrylonitrile. Examples of aromatic vinyls include styrene and α-methylstyrene.

Polymers of vinyl cyanide and aromatic vinyl are produced by known bulk polymerization, suspension polymerization and emulsion polymerization. It is preferably produced by solution polymerization. The acid-modified resin used as the component (C) is a vinyl copolymer containing a carboxyl group. The monomer used for the copolymer of the acid-modified resin is not particularly limited, but the (A),
Transparency (total light transmittance of 75 when mixed with component (B)
% Or more and HAZE 20% or less) must be maintained. Examples thereof include those obtained by copolymerizing a vinyl monomer containing a carboxyl group in the (A) resin and those obtained by copolymerizing a vinyl monomer containing a carboxyl group in the (B) resin. As the vinyl monomer containing a carboxyl group here,
For example, acrylic acid, crotonic acid, cinnamic acid, itaconic acid, unsaturated compounds containing a free carboxyl group such as maleic acid, maleic anhydride, itaconic anhydride, chloromaleic anhydride, citraconic anhydride and other acid anhydrides. Examples of the unsaturated compound containing a type carbonyl group are acrylic acid, methacrylic acid, and maleic anhydride.

The polyamide-imide elastomer used as the component (D) is (a) caprolactam,
(B) Aromatic tricarboxylic acid capable of forming at least one imide ring, aromatic tetracarboxylic acid or an acid anhydride thereof, (c) an organic diisocyanate compound, and (d) a polyoxyalkylene having a number average molecular weight of 500 to 4000. Polyamide imide obtained by reacting glycol and comprising a hard segment obtained from component (a), component (b) and component (c) and glycol of component (d) which is a soft segment are ester-bonded. It is a multi-block type copolymer linked by the above, containing 40 to 64% by weight of polyoxyalkylene glycol and having transparency. In particular, when the amount of the polyalkylene glycol is 64% or more, the strength of the elastomer becomes low, and the mechanical properties become low when kneaded with an acrylic resin or the like, which is not preferable. It is not preferable because the affinity of the compound becomes poor and the antistatic effect becomes low.

The number average molecular weight of the polyamideimide of the hard segment is 500 to 3000, preferably 50.
The range of 0 to 2000 is desirable. This number average molecular weight is 5
If it is less than 00, the melting point is lowered and the heat resistance is lowered,
If it exceeds 000, the affinity with an acrylic resin or the like decreases, which is not preferable. Specific examples of the trivalent aromatic tricarboxylic acid used as the component (b) include:
1,2,4-trimellitic anhydride, 1,2,5-naphthalenetricarboxylic acid, 2,6,7-naphthalenetricarboxylic acid, 3,3 ′, 4-diphenyltricarboxylic acid, benzophenol-3,3 ′, 4-tricarboxylic acid, diphenyl sulfone-3,3 ', 4-tricarboxylic acid, diphenyl ether-3,3', 4-tricarboxylic acid and the like can be mentioned. Further, as the tetravalent aromatic polycarboxylic acid, that is, the aromatic tetracarboxylic acid, specifically, diphenyl-2,2 ', 3,3'-tetracarboxylic acid pyromellitic acid, benzophenone-2,2' , 3,3'-Tetracarboxylic acid, diphenylsulfone-2,2 ', 3,
3'-tetracarboxylic acid, diphenyl ether-2,
2 ', 3,3'- tetracarboxylic acid etc. are mentioned.

The aromatic polycarboxylic acid or its acid anhydride as the component of the component (b) may be used alone or in combination of two or more, and the organic diisocyanate compound as the component (c) and the component (d) may be used. It is used in a substantially equimolar amount, that is, in a range of 0.9 to 1.1 times the molar amount with respect to the total amount of the component glycol. Examples of the organic diisocyanate compound used as the component (c) include hexamethylene diisocyanate, diphenylene diisocyanate, tolylene diisocyanate, isophorodiisocyanate, and diphenylmethane diisocyanate. These diisocyanate compounds may be used alone or in combination of two or more. From the viewpoint of antistatic properties, it is preferable to use polyoxyethylene glycol alone.

As the component (d) in the polyamide-imide elastomer, polyoxyethylene glycol may be used alone or polyoxyethylene glycol 50.
You may use the mixture of polyoxyalkylene glycol containing more than weight% and other polyoxyethylene glycol. From the viewpoint of antistatic properties, it is preferable to use polyoxyethylene glycol alone.

The number average molecular weight of the polyoxyethylene glycol used is not particularly limited, but it is 500 to 5000.
It is preferably in the range of. This number average molecular weight is 500
If it is smaller, the melting point may be lowered or the heat resistance may be insufficient depending on the composition of the elastomer.
If it exceeds, it becomes difficult to obtain a tough elastomer,
When kneaded with an acrylic resin, impact strength and rigidity may decrease, which is not preferable.

The polyoxyalkylene glycol that can be used in combination with the polyoxyethylene glycol is less than 50% by weight of the glycol component and has an average molecular weight of 500 to 4000, such as polyoxytetramethylene glycol, modified polyoxytetramethylene glycol and polyoxytetramethylene glycol. Oxypropylene glycol or the like can be used. The modified polyoxymethylene glycols, typical of oxytetramethylene glycol - (CH ₂₎ include those which are replaced by ₄ -O-. Where R is 2 to 2 carbon atoms
10 alkylene chains, for example ethylene groups, 1,2
-Propylene group, 1,3-propylene group, 2-methyl-
1,3-propylene group, 2,2-dimethyl-1,3-propylene group, pentamethylene group, hexamethylene group and the like can be mentioned. The amount of modification is not particularly limited, but is usually 3
It is selected in the range of up to 50% by weight.

The polyamide-imide elastomer used in the composition of the present invention is preferably polymerized homogeneously, and the homogeneity of this elastomer can be judged by its transparency. Regarding the method for producing the polyamide-imide elastomer, any method may be used as long as a homogeneous polyamide-imide elastomer can be produced. For example, the following method is used.

That is, (a) caprolactam, (b)
The aromatic polycarboxylic acid component (c) the organic diisocyanate compound and the (d) glycol component are mixed in an amount that is substantially equimolar to the total amount of the component (b) and the component (d), and the resulting weight is Moisture content in coalescence is 0.1-1% by weight
While maintaining at 150 to 300 ℃, more preferably 18
It is a method of polymerizing at 0 to 280 ° C. In this method, the reaction temperature can be raised stepwise during dehydration condensation.

At this time, some caprolactam remains unreacted, but this is distilled off under reduced pressure and removed from the reaction mixture.
The mixture after removing the unreacted caprolactam is, if necessary, under reduced pressure at 200 to 300 ° C., more preferably at 23 ° C.
Further polymerization can be performed by post-polymerizing at 0 to 280 ° C. In this reaction method, esterification and amidation are simultaneously caused in the course of dehydration condensation to prevent separation of a coarse layer, thereby producing a homogeneous and transparent elastomer.

The content of this polyamide-imide elastomer must be in the range of 3 to 30% by weight based on the total weight of the components (A), (B) and (C). If this amount is less than 3% by weight, a sufficient antistatic effect cannot be obtained, and if it exceeds 30% by weight, the rigidity becomes insufficient. The components (A), (B), (C), and (D) must satisfy the following formulas (1) and (2) in order for the molded product to show transparency.

[0021]

[Equation 1]

In the composition of the present invention, in order to further improve its antistatic performance, as component (E), dodecylbenzenesulfonic acid, p-toluenesulfonic acid, dodecyldiphenyletherdisulfonic acid, naphthalenesulfonic acid, naphthalenesulfonic acid and formalin are used. Aromatic sulfonic acids such as condensates, alkyl sulfonic acids such as lauryl sulfonic acid, organic carboxylic acids such as stearic acid, lauric acid and polyacrylic acid, organic phosphoric acids such as diphenyl phosphite and diphenyl phosphate, and these At least one selected from among the alkali metal salts and alkaline earth metal salts can be used. Of these, alkali metal salts and alkaline earth metal salts are preferable, and sodium salts and potassium salts are particularly preferable.

The amount of the component (E) blended is such that the component (A) acrylic resin, component (B) vinyl cyanide-aromatic vinyl copolymer, component (C) acid-modified resin and component (D). It is selected in the range of 0 to 10 parts by weight, preferably 0.1 to 10 parts by weight, based on 100 parts by weight of the total of the polyamide imide elastomer as a component. If this amount is less than 0.1 part by weight, the effect is not sufficiently exhibited, and if it exceeds 10 parts by weight, the rigidity is reduced, or when a molded product is formed, the surface of the product is roughened or the molded product is colored. It causes an unfavorable situation.

The method of adding the additive used in the present invention is not particularly limited, but a conventional means such as addition to the resin by an extruder is used. The resin composition of the present invention, if necessary, other components within a range not impairing transparency, for example, pigments, dyes, reinforcing agents, fillers, heat stabilizers, antioxidants, nucleating agents, lubricants, A plasticizer, a release agent, etc. can be contained.

The thermoplastic resin composition thus obtained is a known method generally used for molding thermoplastic resins, for example, injection molding, extrusion molding, blow molding, vacuum molding, inflation molding, film molding. It can be molded by a method such as sheet molding.

[0026]

EXAMPLES The present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. The physical properties of the composition and the elastomer were determined according to the methods described below. (1) Flexural Modulus A test piece having a thickness of 1/4 inch was measured according to ASTM D790 at 23 ° C. and 50% RH. (2) Surface resistivity Using a flat plate with a thickness of 1/8 inch, manufactured by Toa Denpa Kogyo KK,
It was measured under the following conditions using a polar insulating system SM-10E type. (A) After molding, the condition was measured for 24 hours under the conditions of 23 ° C. and 50% RH and then measured (initial surface resistivity). (B) After molding, after leaving it for 360 days, thoroughly washing it with distilled water and removing water from the surface, then at 50% RH and 23 ° C. for 2 hours.
The humidity was measured for 4 hours and then measured (surface resistivity after 360 days). (3) Total light transmittance, HAZE 5 cm × 9 cm, using a flat plate having a thickness of 2.5 mm, the total light transmittance was measured. A haze meter (SM-3 type) manufactured by Suga Test Instruments Co., Ltd. was used for the measurement. (4) Total Energy Absorption Value of Drop Weight Impact Test A drop weight impact test was performed using a flat plate having a size of 5 cm × 9 cm and a thickness of 2.5 mm. For the measurement, a falling weight impact tester manufactured by Toyo Seiki was used. The height of the test is 20 cm, and the weight is 6.5 kg.
The total absorbed energy was calculated as the energy absorbed by the time when the maximum load was reached. (5) Relative Viscosity of Elastomer It was measured in meta-cresol under the conditions of 30 ° C. and 0.5% by weight / volume. Production Example Production of Polyamideimide Elastomer (D-1) 500 equipped with a stirrer, nitrogen inlet and distillation tube
In a ml separable flask, 97 g of caprolactam and 9 of polyoxyethylene glycol having a number average molecular weight of 1470
0 g, trimellitic acid 16.4 g, and diphenylmethane diisocyanate 4.52 g were added to N, N-hexamethylene-
Charge with 0.3 g of bis (3,5-di-t-butyl-4-hydroxycinnamic acid amide) (trade name "Irganox" 1098: antioxidant), and add nitrogen at 50 ml / mi.
The mixture was melted at 150 ° C. while flowing at n, and then polymerized at 260 ° C. for 4 hours. 1 hour, 2 hours,
The water content in the reaction after 4 hours was 0.7, 0.5, and 0.3% by weight. Then, after adding 0.3 g of tetrabutyl orthotitanate, the pressure was gradually reduced to 1 Torr and unreacted caprolactam was distilled out of the system. Further, the mixture was polymerized at the same temperature under a pressure of 1 Torr or less for 2 hours to obtain a transparent elastomer (D-1) having a yellow color (haze: 46%). This elastomer contains 49% by weight of polyoxyethylene glycol segment, has a relative viscosity of 1.93, a melting point of 190 ° C., a crystallization temperature of 121 ° C. and a decomposition temperature of 330 ° C.
Met.

Examples 1 to 5, Comparative Examples 1 to 3 Acrylic resin, AS resin, acid-modified resin, polyamide-imide elastomer, and electrolyte were mixed in the proportions shown in Table 1, and a twin-screw extruder having a screw diameter of 30 mm [Nakaya Machinery Manufactured by
AS30 type], with a cylinder temperature of 230 ° C. and a screw rotation speed of 75 rpm, the mixture is melt-kneaded and extruded at an extrusion speed of 10 kg / hr to form three strands.
Cooled to about 30 ° C with water.

Next, the cooled strand was granulated to obtain a resin composition. After drying the pellets in a gear oven at 80 ° C. for about 3 hours, the cylinder temperature was 240.
Injection molding was performed under conditions of a temperature of 60 ° C. and a mold temperature of 60 ° C. to prepare test pieces for measuring physical properties, surface resistivity, and transmittance.

The properties of the obtained test piece were measured and evaluated according to the methods described above. The results are shown in Table 1. (Note) A-1: Acrylic resin [Asahi Kasei Kogyo KK, Delpet 80N] B-1: AS resin containing 20% vinyl cyanide [Asahi Kasei Kogyo stylac T8707] B-2: Cyan AS resin containing 30% vinyl chloride [manufactured by Asahi Kasei Kogyo KK, Stylak 783] C-1: acid-modified resin [Asahi Kasei Kogyo KK, Delpet 9
80N] C-2: AS resin containing 10% maleic anhydride (containing 20% vinyl cyanide) D-1: Polyamideimide elastomer of the production example E-1: Sodium dodecylbenzenesulfonate E-2: Monoglyceride stearate

[0030]

[Table 1]

[0031]

The thermoplastic resin composition of the present invention comprises an acrylic resin, a copolymer of vinyl cyanide and aromatic vinyl,
Comprising a polyamide-imide elastomer,
It has features such as excellent transparency, rigidity, and permanent antistatic property.
Food containers, medical cassettes, document boxes, various trays such as IC trays, lighting covers, lighting plates, conductive plates,
Carport roof, greenhouse roof, showcase, tableware, clock face cover, car interior and exterior parts, TV stand door, goldfish bee, bird cage, insect cage, vegetable storage box in refrigerator, meter nameplate , VTR cassette window, computer magnetic tape container, VTR cassette case, C
It is suitable for use in fields such as D cases, MFD cassette cases, wares, and trays.

Continuation of the front page (51) Int.Cl. ⁵ Identification number Office reference number FI Technical display location C08L 33/02 LJA 7921-4J 33/20 LJJ 7921-4J LJM 7921-4J 79/08 LRC 9285-4J

Claims (1)

[Claims] 1. (A) 1 to 96% by weight of an acrylic resin,
And (B) 1 to 96% by weight of a copolymer of vinyl cyanide and aromatic vinyl, (C) 0 to 30% by weight of an acid-modified resin, and (D) 3 to 30% by weight of a polyamideimide elastomer. (E) with respect to 100 parts by weight of the resin composition
An antistatic resin composition comprising 0 to 10 parts by weight of at least one selected from organic electrolytes and inorganic electrolytes, and further refraction of a mixture of (A) + (B) + (C) The difference between the refractive index and the refractive index of the component (D) is 0.02 or less, and a transparent thermoplastic resin composition having excellent antistatic properties.