JPH0546368B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing a thermoplastic resin having excellent heat resistance, water resistance, and impact resistance. Methyl methacrylate-based methacrylic resin has excellent weather resistance and optical properties, as well as relatively well-balanced performance in mechanical properties, thermal properties, and moldability. Taking advantage of this, it is used in many fields such as automobile parts, electrical equipment parts, nameplates, signboards, lighting covers, decorations, and miscellaneous goods. However, on the other hand, their heat resistance is not necessarily sufficient, and their use is limited in fields where shape stability at high temperatures is required, and there is a deep-rooted demand for improved heat resistance. There have already been many proposals for methods of improving the heat resistance of methacrylic resins, such as copolymerization of methyl methacrylate and N-arylmaleimide (Japanese Patent Publication No. 43-9753), methyl methacrylate, α-methyl A method has been proposed in which a copolymer of styrene and maleic anhydride is blended with a methyl methacrylate polymer (Japanese Unexamined Patent Publication No. 122536/1983). However, although these methods improve heat resistance to some extent, they still have problems such as deterioration of mechanical properties, weather resistance, and optical properties, marked discoloration of molded products, and poor moldability. There is. In addition, attempts have been made to improve the impact resistance by a multi-step polymerization method of methyl methacrylate and an acrylic acid alkyl ester to form a soft polymer (Japanese Patent Application Laid-Open No. 59-202213); There are problems such as reduced impact resistance,
The reality is that each has not gone beyond the level of individual performance improvement. Furthermore, if the water resistance is poor or the moisture absorption rate is high, the dimensional stability of the molded product will deteriorate, so there is a strong demand for improvement, especially in the field of precision molding. In view of these circumstances, the present inventors have developed a method that improves properties such as heat resistance, water resistance, and impact resistance without reducing the excellent properties of methacrylic resin such as weather resistance, optical properties, and moldability. The present invention was completed as a result of intensive research to obtain an excellent thermoplastic resin. That is, the present invention (In the formula, R is hydrogen, alkyl having 1 to 15 carbon atoms, cycloalkyl, aryl group or substituted aryl group.) 0.5 to 60% by weight of a maleimide compound A represented by
Methyl methacrylate or its partial polymer B20
~99% by weight, methacrylic acid esters C0.5 having an alkyl group having 3 to 18 carbon atoms and no cyclic structure
The present invention relates to a method for producing a thermoplastic resin in which 0 to 40% by weight of the present invention and 0 to 40% by weight of other monomers D copolymerizable with these monomers are polymerized. The manufacturing method of the present invention has excellent heat resistance, water resistance, impact resistance, solvent resistance, and dimensional stability, as well as excellent weather resistance, optical properties, mechanical properties, moldability, and color banding of molded products. It also provides an extremely well-balanced thermoplastic resin composition. The maleimide compound A used in the production method of the present invention is a component mainly for imparting heat resistance, solvent resistance, and hardness such as improvement of thermal decomposition temperature and heat distortion temperature, and is a component for imparting heat resistance, solvent resistance, and hardness such as improvement of thermal decomposition temperature and heat distortion temperature. Combined B has the inherent weather resistance and optical properties of methacrylic resin,
Methacrylic acid ester C, which is a component for maintaining mechanical properties and has an alkyl group having 3 to 18 carbon atoms and does not have a cyclic structure, has water resistance, impact resistance,
A component for imparting weather resistance and optical properties. Therefore, the manufacturing method of the present invention consists of combining components A, B, C and, if necessary, component D, and the synergistic effect of each component allows it to achieve well-balanced and excellent properties that have not been previously available. A thermoplastic resin having the following properties is obtained. Maleimide compound A used in the production method of the present invention
is represented by the above general formula, such as maleimide, N-methylmaleimide, N-ethylmaleimide, N-propylmaleimide, N-isopropylmaleimide, N-butylmaleimide, N-isobutylmaleimide, N-tertiarybutyl maleimide, N-cyclohexylmaleimide, N-phenylmaleimide, N-chlorophenylmaleimide, N-methylphenylmaleimide, N-naphthylmaleimide, N-laurylmaleimide, 2-hydroxyethylmaleimide, N-hydroxyphenylmaleimide, Examples include N-methoxyphenylmaleimide, N-carboxyphenylmaleimide, N-nitrophenylmaleimide, N-tribromophenylmaleimide, and one or more of these can be used. . N
- When tribromophenylmaleimide is used, flame retardancy can also be imparted to the resin composition. Maleimide compound A is 0.5 in the copolymer.
It is used in a proportion of ~60% by weight, preferably 5-30% by weight. If the amount of Compound A used is less than 0.5% by weight, sufficient heat resistance and hardness cannot be imparted to the resulting resin, and if the amount is more than 60% by weight, moldability and impact resistance of the resulting resin may be impaired. Both are unfavorable because they reduce performance. Methyl methacrylate or its partial polymer B
is a polymerizable syrup which is a mixture of methyl methacrylate and a methyl methacrylate polymer obtained by prepolymerizing methyl methacrylate or methyl methacrylate by a conventional method. Methyl methacrylate or its partial polymer B is in the copolymer
It is used in a proportion of 20 to 99% by weight, preferably 40 to 85% by weight. If the amount used is less than 20% by weight, the resulting resin will not be able to maintain the original weather resistance and optical properties of the methacrylic resin, and
In amounts greater than 99% by weight, the weather resistance of the resulting resin
Both are unfavorable because water resistance and impact resistance decrease. Methacrylic esters C are methacrylic esters having an alkyl group having 3 to 18 carbon atoms without a cyclic structure, such as propyl methacrylate, isopropyl methacrylate, butyl methacrylate, isobutyl methacrylate, and tert-butyl methacrylate. , amyl methacrylate, isoamyl methacrylate, octyl methacrylate, 2-ethylhexyl methacrylate, decyl methacrylate, lauryl methacrylate, benzyl methacrylate, 2-phenoxyethyl methacrylate, 3-phenylpropyl methacrylate, etc. , one or more of these may be used.
Methacrylic acid ester C is 0.5 to 40 in the copolymer.
It is used in a proportion of 10 to 30% by weight, preferably 10 to 30% by weight. If the amount used is less than 0.5% by weight, the moldability, impact resistance, and water resistance of the resulting resin will be reduced, and if the amount is more than 40% by weight, the heat resistance will be reduced, both of which are not preferred. Furthermore, one type or two or more types of other monomers D that can be copolymerized with components A, B, and C may be used depending on the purpose. Monomer D includes vinyl aromatics such as styrene, α-methylstyrene, paramethylstyrene, isopropenylstyrene, vinyltoluene, and chlorostyrene; unsaturated compounds such as acrylonitrile, methacrylonitrile, ethacrylonitrile, and phenyl acrylonitrile. Nitriles; cycloalkyl group,
Acrylic esters having an alkyl group containing a benzyl group having 1 to 18 carbon atoms, such as methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, butyl acrylate, isobutyl acrylate, tert-butyl acrylate, acrylic amyl acid, isoamyl acrylate,
Octyl acrylate, 2-ethylhexyl acrylate, decyl acrylate, lauryl acrylate,
Examples include cyclohexyl acrylate and benzyl acrylate. Furthermore, olefins such as ethylene, propylene, isobutylene and diisobutylene; dienes such as butadiene and isoprene; methyl vinyl ether,
Vinyl ethers such as butyl vinyl ether; Vinyl esters such as vinyl acetate and vinyl propionate; Vinyl fluorides such as vinylidene fluoride; Allyl esters or methallyl esters of saturated aliphatic monocarboxylic acids such as allyl acetate and allyl propionate Class; ethylene glycol diacrylate or methacrylate, diethylene glycol diacrylate or methacrylate, divinylbenzene, diallyl phthalate, trimethylolpropane triacrylate or methacrylate, hexanediol diacrylate or methacrylate,
pentaerythritol tetraacrylate or methacrylate, dipentaerythritol hexaacrylate or methacrylate, diacrylate or methacrylate of ethylene oxide or propylene oxide adduct of bisphenol A,
Polyhydric acrylates such as diacrylates or methacrylates of ethylene oxide or propylene oxide adducts of halogenated bisphenol A, triacrylates or methacrylates of isocyanurates, di- or triacrylates or methacrylates of ethylene oxide or propylene oxide adducts of isocyanurates, or Methacrylates; polyvalent arylates such as triallyl isocyanurate; glycidyl acrylate or methacrylate, glycidyl compounds such as allyl glycidyl ether; acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, or their half-esters, etc. Various monomers such as unsaturated carboxylic acids may be mentioned, and one or two of these monomers may be used.
You can use more than one seed. Monomer D is used in the range of 0 to 40% by weight in the copolymer, but if the amount used is more than 40% by weight, the resulting resin will have poor weather resistance, heat resistance, transparency, moldability, etc. This is undesirable because it upsets the balance and causes a drop in performance. Monomer D may be used appropriately depending on the purpose, but for example, if higher impact resistance is required, a partially crosslinked rubber latex may be prepared using butyl acrylate or butadiene as the monomer D component. Then, A, B and C were added to the rubber latex.
If necessary, a method is adopted in which a copolymer, that is, a thermoplastic resin is obtained by further graft polymerization with component D, or a method in which styrene is used to adjust the refractive index of the copolymer. In addition, when a large amount of acrylic esters is used, moldability improves, but heat resistance may decrease.Furthermore, when a large amount of polyacrylates, methacrylates, polyarylates, or metharylates is used, heat resistance deteriorates. Although improvements can be seen, moldability may be extremely reduced.
Sufficient consideration is required when using them. In the production method of the present invention, radical polymerization or ionic polymerization can be employed as a method for polymerizing each of the components as described above, but radical polymerization is generally used. That is, conventionally known methods such as suspension polymerization, emulsion polymerization, bulk polymerization, solution polymerization, or a suitable combination thereof may be employed. The polymerization is carried out under autogenous pressure or under pressure, under an inert gas atmosphere, at temperatures from 0° C. or less to 100° C. or more. The polymerization initiator used during the polymerization is a commonly used free radical polymerization initiator, such as benzoyl peroxide potassium persulfate, ammonium persulfate,
Oil-soluble or water-soluble peroxides such as hydrogen peroxide and azo compounds such as azobisisobutyronitrile are suitable. It is also possible to use a reducing agent such as sodium bisulfite, ascorbic acid, or ferrous sulfate in combination to effectively advance the polymerization. Suspension stabilizers used during suspension polymerization include commonly used suspension stabilizers, such as calcium carbonate, barium carbonate, magnesium carbonate, polyvinyl alcohol, and copolymers of methacrylic acid and methacrylic acid ester. An alkali metal salt or the like may be used. Emulsifiers used during emulsion polymerization include commonly used emulsifiers, such as anionic emulsifiers such as potassium oleate, sodium dodecylbenzenesulfonate, and sodium lauryl sulfate; polyoxyethylene nonylphenol ether, polyoxyethylene Nonionic emulsifiers such as sorbitan ester; cationic emulsifiers such as lauryltrimethylammonium chloride may be used as appropriate. The organic solvents used during solution polymerization are commonly used organic solvents, such as toluene, xylene, methyl isobutyl ketone, butyl cellosolve, dimethyl formamide, 2-methylpyrrolidone, and Solbetsuso #100 (manufactured by Tonen Petrochemical Co., Ltd.). Organic solvents such as the like may be used as appropriate. The outline of thermoplastic resin production will be explained below using suspension polymerization as an example. Suspension stabilizer For example, a maleimide compound A, methyl methacrylate or its partial polymer B, and a carbon atom having 3 to 18 carbon atoms without a cyclic structure are added to an aqueous solution at room temperature or under heating in which polyvinyl alcohol is dissolved. A homogeneous mixture obtained by adding and dissolving a polymerization initiator (for example, benzoyl peroxide) to a mixture of methacrylic acid esters C having an alkyl group and, if necessary, other monomers D copolymerizable with these, is mixed with an inert gas ( For example, nitrogen gas) is added under aeration and stirring to form a suspension, then the temperature is raised to a predetermined reaction temperature (usually 60 to 100°C) to initiate polymerization, and the polymerization is maintained at a predetermined temperature range for a certain period of time. complete. After the polymerization is completed, the reaction product is subjected to cooling, filtration, water washing, and drying steps to obtain the desired thermoplastic resin. Most of the maleimide compound A that makes up the thermoplastic resin is solid at room temperature, so in some cases it may not completely dissolve in the organic solvent used or other monomers such as methyl methacrylate at room temperature. . In such a case, taking the above suspension polymerization as an example, the mixture containing no polymerization initiator is added to an aqueous suspension stabilizer solution with stirring, and then the solubility of maleimide compound A in other monomers is determined. After heating to the above temperature and uniformly suspending the mixture, a polymerization initiator is added and polymerization is performed to obtain the desired thermoplastic resin. The molecular weight of the thermoplastic resin obtained in the present invention is not particularly limited, but if it is too high, the moldability may deteriorate, and if it is too low, the weather resistance may deteriorate.
Usually 5,000 to 2,000,000, preferably 10,000 because it has disadvantages such as poor heat resistance and mechanical properties.
A range of 1,000,000 to 1,000,000 is preferred. To adjust the molecular weight, commonly used chain transfer agents such as butyl mercaptan, tertiarydodecyl mercaptan, mercaptoethanol, etc. may be used. The thermoplastic resin obtained in this way can be effectively used for various purposes, but in the present invention, the thermoplastic resin is further combined with other polymers or copolymers to form a thermoplastic resin. It can also be a composition. The method for producing the thermoplastic resin composition is not particularly limited, and includes not only a method of mechanically mixing the thermoplastic resin obtained by the present invention and other polymers, but also suspension polymerization, emulsion polymerization, Conventionally known methods such as bulk polymerization or a combination of these methods may be used. For example, in the production method of the present invention, after mixing a thermoplastic resin obtained by suspension polymerization, bulk polymerization, etc. with another polymer,
A method of preparing a thermoplastic resin composition by melting, kneading, and extruding at a temperature of 300°C; adding the thermoplastic resin obtained by the production method of the present invention to the monomer mixture used to produce the polymer. A method of bulk polymerization, suspension polymerization or emulsion polymerization in an aqueous medium containing a suspension stabilizer in the presence of a resin; Method of polymerization or emulsion polymerization; emulsion polymerization of the monomer mixture used in the present invention, and then adding and polymerizing the monomers used to produce the polymer into the obtained emulsion copolymer. Examples include a method of producing a uniform and highly dispersible emulsion, followed by coagulation, washing with water, and drying to obtain a powdery resin composition. For the polymerization reaction employed to produce the thermoplastic resin composition, the same method as used for producing the thermoplastic resin in the present invention described above is employed. The thermoplastic resin of the present invention may contain various additives, such as ultraviolet absorbers, stabilizers,
It may contain known additives such as mold release agents. The thermoplastic resin of the present invention takes advantage of its characteristics such as weather resistance, heat resistance, water absorption resistance, and impact resistance, and can be used as a molding material, extruded plate, cast plate, etc. in various fields of application, such as automobile parts, electrical equipment parts, etc. , building materials,
It can be used not only as general-purpose engineering plastics such as signboards, display products, and lighting equipment, but also in fields such as optical fibers and optical disks. EXAMPLES Next, the present invention will be specifically explained with reference to Examples, but it goes without saying that the present invention is not limited to these Examples. In addition, parts in the examples represent parts by weight, and % represents weight %. Example 1 560 parts of deionized water and 0.28 parts of polyvinyl alcohol (Gohsenol GH-20, manufactured by Nippon Gohsei Co., Ltd.) were charged into the four-necked stainless steel flask equipped with a stirrer in 1, and the mixture was heated to 80°C under a nitrogen gas atmosphere. After heating to dissolve the polyvinyl alcohol, the mixture was cooled to 50°C. Weigh out 156 parts of methyl methacrylate, 48 parts of cyclohexylmaleimide, and 36 parts of isobutyl methacrylate in a separate container, heat it to 40°C to dissolve the cyclohexylmaleimide, and then add benzoyl peroxide.
7.2 parts, trade name "Tinuvin P" (manufactured by Ciba Geigy) 0.07 parts, and stearic acid monoglyceride
0.2 part was added to obtain a uniform monomer solution. This monomer solution was added to the flask and kept under stirring at 400 rpm for 10 minutes under a nitrogen gas atmosphere to make the monomer solution into a suspended state, and then the internal temperature was raised to 80°C. Polymerization was started and then maintained at this temperature for 7 hours to complete the polymerization. The obtained reaction solution was filtered through a 100-mesh filter cloth, thoroughly washed with deionized water, and then dried in a hot air circulation dryer at 90°C to obtain a thermoplastic resin of the present invention with a diameter of about 0.5 mm. About 230 parts of granular copolymer 1 was obtained. The obtained copolymer 1 was heated to a cylinder temperature of 250 to 260
A test piece (110 mm x 110 mm x 3 mm) was obtained by injection molding at an injection pressure of 700 kg/cm ² and a mold temperature of 50° C. Using the obtained test pieces, various performance tests were conducted, and the second
The evaluation results shown in the table were obtained. Comparative Examples 1 to 4 Comparative (co)polymers 1 to 4 having the monomer composition shown in Table 1 were prepared in the same manner as in Example 1, and test pieces were obtained in the same manner as in Example 1. The evaluation results are shown in Table 2.

【expressed.

【table】

[Table] Examples 2 to 4 Copolymers 2 to 4 were prepared in the same manner as in Example 1, except that the monomer composition shown in Table 3 was used, and test pieces were obtained in the same manner as in Example 1. The evaluation results are shown in Table 4.

【expressed.

[Table] Reference usage example After mixing 50 parts of Copolymer 1 obtained in Example 1 and 50 parts of Comparative Polymer 1 obtained in Comparative Example 1, 200~ Shaped at 270℃,
A pellet-shaped thermoplastic resin composition 1 was obtained. This thermoplastic resin composition 1 was heated to a cylinder temperature of
Test pieces were obtained by injection molding at 250 to 260°C, injection pressure of 700 Kg/cm ² and mold temperature of 50°C, and the evaluation results shown in Table 6 were obtained. Comparative Examples 5 to 7 Thermoplastic resin compositions 1 to 3 for comparison of the compounding compositions shown in Table 5 were prepared in the same manner as in the reference usage example,
The evaluation results shown in Table 6 were obtained using test pieces obtained in the same manner as in the reference use example.

【table】

【table】

【table】

Claims (1)

[Claims] 1. General formula (In the formula, R is hydrogen, alkyl having 1 to 15 carbon atoms, cycloalkyl, aryl group or substituted aryl group.) 0.5 to 60% by weight of a maleimide compound A represented by
Methyl methacrylate or its partial polymer B20
~99% by weight, methacrylic acid esters C0.5 having an alkyl group having 3 to 18 carbon atoms and no cyclic structure
~40% by weight and other monomers copolymerizable with these
A method for producing a thermoplastic resin by polymerizing 0 to 40% by weight of D.