JP2582403B2 - Methyl methacrylate-styrene resin composition with excellent heat resistance and weather resistance - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a novel methyl methacrylate-styrene resin composition, and more particularly, to a colorless and transparent resin composition having excellent weather resistance, and The present invention relates to a heat-resistant methyl methacrylate-styrene resin composition capable of maintaining transparency for a long period of time.

(Prior art and problems) In recent years, the demand for resins that have excellent heat resistance in various applications such as tableware in microwave ovens, weak electric parts, and industrial parts, and that are colorless, transparent, and inexpensive has become particularly strong. is there.

By the way, polycarbonate resin (hereinafter abbreviated as PC) is known as a resin which is colorless and transparent and has excellent heat resistance among resins currently on the market, but this resin is an engineering plastic and is expensive. Therefore, it has not reached general use. In addition, polycarbonate resins have a disadvantage that they are easily damaged due to their low surface hardness and colorless transparency cannot be maintained for a long period of time.

On the other hand, methyl methacrylate-styrene resin (hereinafter, referred to as
It is called MS resin. Is a resin having both high transparency and mechanical strength of a methyl methacrylate resin and moldability of a styrene resin, and because of its relatively low cost, its potential demand is increasing. However, this MS resin has insufficient heat resistance like methyl methacrylate resin and styrene resin, and has poor weather resistance due to the use of styrene. At present, the range of use is severely limited due to discoloration.

(Problems to be Solved by the Invention) Under such circumstances, an object of the present invention is to identify an MS resin composition having excellent heat resistance and weather resistance. The present inventors have found that a heat-resistant MS-based resin having unprecedented weather resistance can be obtained by adding a specific amount of a specific stabilizer to a copolymer having a composition.

(Means for Solving the Problems) That is, the present invention provides a compound represented by the general formula (In the formula, R is hydrogen, an alkyl group having 1 to 18 carbon atoms, a cycloalkyl group, an aryl group, or a substituted aryl group.)
5 to 30% by weight of a maleimide compound (A), 10 to 85% by weight of methyl methacrylate (B), styrene (C)
10 to 85% by weight and 0 to 30% by weight of the other polymerizable monomer (D) copolymerizable with these monomers (however, the total of the monomers is 100% by weight). Methyl methacrylate-styrene resin (a) obtained by polymerizing the polymerizable monomer component (a) (hereinafter referred to as MS resin (a)) 100 parts by weight, and ultraviolet absorber (b) 0.001 to 0.5 Parts by weight, 0.001 to 1 part by weight of a thioether-based organic sulfur stabilizer (c), 0.001 to 2 parts by weight of a phosphite compound (d) and, if desired, 0 to 1 part by weight of a bisphenol-based antioxidant (e) An object of the present invention is to provide an MS resin composition having excellent heat resistance and weather resistance.

In the composition of the present invention, the MS resin (a) essentially contains a maleimide compound (A), methyl methacrylate (B), and styrene (C), and optionally another polymerizable monomer (D).
Are configured in combination.

The maleimide compound (A) causes the MS resin (a) and thus the resin composition of the present invention to exhibit remarkable improvements in heat resistance and solvent resistance, and is represented by the above general formula. -Methylmaleimide, N-ethylmaleimide, N-propylmaleimide, N-isopropylmaleimide, N-butylmaleimide, N-isobutylmaleimide, N-tert-butylmaleimide, N-cyclohexylmaleimide, N-phenylmaleimide, N-c Lorphenylmaleimide, N-methylphenylmaleimide, N-naphthylmaleimide, N-octylmaleimide, N-laurylmaleimide, N-stearylmaleimide, N-2-hydroxyethylmaleimide, N-hydroxyphenylmaleimide, N-methoxyph Enenyl maleimide, N-carboxy Enyl maleimide, N- nitrophenyl maleimide, there may be mentioned N- tribromo-phenylalanine maleimide, among these, can be used alone or in combination. Further, among the maleimide compounds (A), N-methylmaleimide, N-isopropylmaleimide, N-cyclohexylmaleimide, N-orthochloromaleimide and the like are more preferably used from the viewpoint of the optical properties and mechanical properties of the polymer.

The maleimide compound (A) has a content of 5 to 5 in the polymerizable monomer component.
It is used in a proportion of 30% by weight, preferably 10 to 20% by weight. If the amount of the compound (A) is less than 5% by weight, the obtained resin cannot be provided with sufficient heat resistance.
If the content is more than 10% by weight, the moldability and impact resistance of the obtained resin are undesirably reduced.

Methyl methacrylate (B) is a component for improving the weather resistance, impact resistance, and optical properties of the MS resin, and its use amount is 10 to 85% by weight, preferably 20% by weight in the polymerizable monomer component.
It is used at a ratio of up to 80% by weight. If the amount of methyl methacrylate (B) is less than 10% by weight, the weather resistance and optical properties of the resin will be reduced, and if it is more than 80% by weight, the processability of the obtained resin will be reduced, which is not preferable.

Styrene (C) improves the processability of the MS resin (a) and the copolymerization reactivity of the maleimide compound (A). As a result, the effect of improving the heat resistance becomes remarkable, and the unreacted maleimide compound (A) ) Reduces the amount of unreacted substances and contributes to an improvement in productivity. Styrene (C) is used in an amount of 10 to 85% by weight, preferably 20 to 80% by weight, in the polymerizable monomer component. If the amount of styrene (C) is less than 10% by weight, the copolymerization reactivity of the maleimide compound (A) decreases, the amount of unreacted substances increases, and the moldability of the obtained MS resin (A) deteriorates. In addition, MS obtained when it exceeds 85% by weight
Both of these are undesirable because the mechanical properties, optical properties, and the like of the system resin (a) decrease.

In the present invention, the polymerizable monomer component may be composed only of the maleimide compound (A), methyl methacrylate (B) and styrene (C), but the polymerizable monomer component is not impaired in the characteristics of the present invention. The monomer (D) may be used. The polymerizable monomer (D) that can be used is one that can be copolymerized with at least one of the maleimide compound (A), methyl methacrylate (B) and styrene (C) used. There is no particular limitation, for example, methyl acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, tertiary butyl (meth) acrylate, amyl (meth) acrylate, octyl (meth) acrylate, 2- Cycloalkyl groups such as ethylhexyl (meth) acrylate, lauryl (meth) acrylate, cyclohexyl (meth) acrylate, and benzyl (meth) acrylate; acrylates having 1 to 12 carbon atoms in alkyl groups including benzyl groups; or carbon in alkyl groups Methacrylates having the numbers 2 to 12; α Vinyl aromatics other than styrene such as methylstyrene, paramethylstyrene, isopropenylstyrene, and vinyltoluene; unsaturated nitriles such as (meth) acrylonitrile; olefins such as ethylene and propylene; dienes such as butadiene and isoprene; Vinyl esters such as vinyl acetate; vinyl halides such as vinyl chloride and vinyl fluoride; and many such as ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate and divinylbenzene. Unsaturated compounds and the like can be mentioned, and 1 is selected from these groups.
Species or two or more can be used. The polymerizable monomer (D) may be used, if necessary, based on the total amount of the polymerizable monomer components.
It is used in an amount of 30% by weight or less. If the amount used exceeds 30% by weight, MS resin with excellent transparency and heat resistance (a)
Can not be obtained.

MS resin constituting MS resin composition of the present invention (A)
Can be prepared according to known procedures using a polymerizable monomer component containing the maleimide compound (A), methyl methacrylate (B), styrene (C) and optionally a polymerizable monomer (D) in the above-mentioned amounts. And then copolymerize. The polymerization method is not particularly restricted but includes, for example, suspension polymerization, emulsion polymerization, solution polymerization and bulk polymerization. In the present invention, the MS resin (a) having particularly excellent performance according to the suspension polymerization method
Is preferred because it can be safely produced. The outline of the production of the MS-based resin (A) constituting the MS-based resin composition of the present invention will be described below by taking a suspension polymerization method as an example.

Maleimide compound (A), methyl methacrylate (B), styrene (C) and, if necessary, copolymerization with a suspension stabilizer such as polyvinyl alcohol dissolved in an aqueous solution at room temperature or at room temperature. A homogeneous mixture obtained by adding and dissolving a polymerization initiator (for example, benzoyl peroxide) to a polymerizable monomer component comprising another possible monomer (D) is dissolved under an inert gas (for example, nitrogen gas) and stirring. Added to
After the suspension, the reaction temperature (usually 60 to 100)
(° C.) to start polymerization, and maintain the mixture at a predetermined temperature range for a certain period of time to complete the polymerization. After completion of the polymerization, the reaction product is cooled, filtered, washed with water, and dried to obtain the desired MS resin (a).

The molecular weight of the MS-based resin (a) is not particularly limited, but if it is too high, the moldability of the resin composition will be poor, and if it is too low, weather resistance, heat resistance, mechanical properties, etc. will be poor. Because of the drawbacks such as becoming, usually 10,000 ~ 1,
Suitable in the range of 000,000, preferably 50,000 to 500,000. For controlling the molecular weight, generally used chain transfer agents such as butyl mercaptan, tertiary decyl mercaptan and mercaptoethanol may be used.

Next, the composition of the stabilizer based on 100 parts by weight of the MS resin (a) is shown below.

The ultraviolet absorber (b) is a component for improving the weather resistance of the MS-based resin composition, and examples thereof include benzophenone-based, benzotriazole-based, benzoate-based, and cyanoacrylate-based ones. -(5-methyl-2-hydroxyphenyl) benzotriazole, 2- (3,5-di-t-butyl-2-
(Hydroxyphenyl) benzotriazole, etc., and is used in an amount of 0.001 to 0.5 part by weight based on 100 parts by weight of the MS resin (A).

The phosphite compound (c) is a component that imparts thermal stability to the MS-based resin composition and includes, for example, tris (nonylphenyl) phosphite, tris (mono- and dinonylphenyl) phosphite, and 100 parts by weight of the MS-based resin (a). 0.001 to 2 parts by weight with respect to the weight.

The thioether-type organic sulfur-based stabilizer (d) exerts a surplus effect when used in combination with the phosphite compound (c), thereby significantly improving the thermal stability. Even more surprisingly, when used in the production of the MS resin (a), the effect as a chain transfer agent also appears as a secondary effect, and the MS resin (a) has a low molecular weight and a sharp molecular weight distribution. Also contributes. Therefore, by using as a substitute for the conventional mercaptans for improving the moldability, it is possible to avoid odor to the resin.

Bisphenol-based antioxidants (e), for example, triethylene glycol-bis [3- (3-t-butyl-5-methyl-4-hydroxyphenyl) propionate] and the like can be used, if desired, with MS-based resin (a) 100 0-1 for parts by weight
Parts by weight can be blended.

The MS resin composition of the present invention further optionally, for example, an organic acid metal salt, a pigment, a filler, a foaming agent, an antistatic agent,
Anti-fogging agent, surface treatment agent, lubricant, flame retardant, fluorescent agent, fungicide,
Metal deactivators, infrared absorbers, processing aids, release agents, reinforcing agents and the like can be included.

(Effect of the Invention) The MS resin composition of the present invention is colorless and transparent, and has remarkably excellent heat resistance and weather resistance by mixing a specific compound with the MS resin (a) having excellent heat resistance. And
Colorless transparency can be maintained for a long time without discoloration even by external influence of heat or light.

Therefore, the MS-based resin composition having excellent heat resistance and weather resistance of the present invention can be suitably used as a member for various uses such as a tableware in a microwave oven, a weak electric component, or an industrial component.

EXAMPLES Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited to the following examples.
In the examples, parts are by weight unless otherwise specified.

Example 1 10 parts of N-cyclohexylmaleimide, 36 parts of methyl methacrylate, 54 parts of styrene, lauroyl peroxide 0.1 part
5 parts and ditridecyl-3,3'-thiodipropionate
A 0.5 part polymerizable monomer component is charged into a reaction vessel equipped with a reflux condenser, an inert gas inlet tube, a thermometer and a stirrer together with 300 parts of deionized water and 1.5 parts of sodium polymethacrylate, and stirred at high speed. To form a suspension. Then, the reaction solution was heated to 80 ° C. while blowing nitrogen gas from an inert gas inlet tube to start a polymerization reaction. 5 after the polymerization reaction has started
After an hour, the temperature of the reaction solution was raised to 95 ° C., and stirring was continued for another 2 hours to complete the polymerization. The obtained copolymer was cooled, filtered, washed with water, and dried to obtain beads of the MS resin (1). Next, 100% by weight of this MS resin (1) was used as an ultraviolet absorber (b) as Tinuvin P (Nippon Ciba Geigy Co., Ltd.).
UV absorber manufactured by 0.1 parts by weight, Sumilizer TL as a thioether-based organic sulfur stabilizer (c) Secondary antioxidant manufactured by Sumitomo Chemical Co., Ltd .: 0.5 parts by weight, MARK-329K as phosphite compound (d) ｛Adeka. Add 0.9 parts by weight of antioxidant manufactured by Argus Chemical Co., Ltd. and 0.3 parts by weight of IRGANOX-245 {antioxidant manufactured by Nippon Ciba Geigy Co., Ltd.} After sufficient mixing, the mixture was melt-kneaded using a vented 30 mm extruder under the conditions of a vent pressure of 30 mmHg and a cylinder temperature of 250 ° C., and pelletized.

The pellet of the obtained MS-based resin composition (1) was subjected to high-pressure and high-speed injection molding at a molding temperature of 250 ° C. using an injection molding machine (PS60E9A type manufactured by Nissei Plastic Industry Co., Ltd.).
The appearance of the molded article of the system resin composition (1) was colorless and transparent, and no silver was generated. Further, the performance of this molded product was tested, and the results are shown in Table 1. The method of measuring the heat distortion temperature of the performance was in accordance with ASTM D-648, the Izod impact strength was in accordance with ASTM D-256, the yellowness (YI) was in accordance with JISK-7103, and the appearance was determined by visual observation.

Examples 2 to 4 and Comparative Examples 1 to 4 Following the same method as in Example 1 except that the polymerizable monomer component and the stabilizer component used in Example 1 were as shown in Table 1. Molded articles of the MS resin compositions (2) to (4) and the comparative resin compositions (1) to (4) were obtained. The performance of these molded products was tested, and the results are shown in Table 1.

Comparative Examples 5 to 9 Comparative resin compositions (Examples 1 to 9) were prepared in the same manner as in Example 1 except that the polymerizable monomer component and the stabilizer component used in Example 1 were as shown in Table 2. 5) to (9) were obtained. The performance of these molded articles was tested, and the results are shown in Table 2.

──────────────────────────────────────────────────の Continuation of the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical display location C08L 35/02 LJW C08L 35/02 LJW (72) Inventor Keishi Tsuboi 992 Nishioki, Okihama-shi, Abashiri-ku, Himeji-shi, Hyogo No. 1 within Himeji Laboratory, Nippon Shokubai Chemical Industry Co., Ltd. (72) Inventor Akiaki Fujiwara 992, Nishioki, Okihama-shi, Aboshi-ku, Himeji-shi, Hyogo Prefecture No. 1 inside Himeji Lab, Nihon Shokubai Chemical Industry Co., Ltd. -252458 (JP, A) JP-A-62-141066 (JP, A) JP-A-59-221343 (JP, A)

Claims (1)

(57) [Claims] (1) General formula (In the formula, R is hydrogen, an alkyl group having 1 to 18 carbon atoms, a cycloalkyl group, an aryl group, or a substituted aryl group.)
5 to 30% by weight of a maleimide compound (A), 10 to 85% by weight of methyl methacrylate (B), styrene (C)
10 to 85% by weight and 0 to 30% by weight of the other polymerizable monomer (D) copolymerizable with these monomers (however, the total of the monomers is 100% by weight). Methyl methacrylate-styrene resin obtained by polymerizing a polymerizable monomer component (A) 100 parts by weight, ultraviolet absorber (B) 0.001 to 0.5 parts by weight, thioether-based organic sulfur stabilizer (C) 0.001 to 1 part by weight, a phosphite compound (d) 0.001 to 2 parts by weight and, if desired, 0 to 1 part by weight of a bisphenol-based antioxidant (e) are blended to provide heat resistance and weather resistance. Excellent methyl methacrylate-styrene resin composition.