JPH0129505B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a heat-resistant resin composition. More specifically, the present invention provides a heat-resistant resin composition having excellent heat resistance and impact resistance, which is suitably used for automobile parts, industrial parts, home appliance parts, etc., by mixing a heat-resistant copolymer and a graft rubber. It is related to. (Prior art) Thermoplastic resin obtained by graft polymerizing acrylonitrile and styrene to rubber whose main component is butadiene is known as ABS resin.
Because it has excellent properties such as processability, mechanical strength, surface gloss, and chemical resistance, it is widely used in many fields today, and as its application fields expand, demand for it is also increasing. It is in. With the expansion of such fields of use, the performance requirements are becoming increasingly strict, and one of these is the need for products with further improved heat resistance. Conventionally, as a method to improve the heat resistance of ABS resin, some or all of the styrene was
-It is known to be replaced with methylstyrene. For example, in order to obtain a resin with excellent heat resistance,
It has been proposed to replace styrene with methyl methacrylate and α-methylstyrene (Japanese Patent Publication No. 49-37415). However, even though the heat resistance is improved by introducing α-methylstyrene, the polymerization rate decreases significantly as the amount increases, and processability and impact resistance deteriorate, making it difficult for ABS resins to In addition, there is a limit to the improvement in heat resistance that can be achieved by introducing α-methylstyrene. It is not necessarily satisfactory for the intended use. There is also a disclosure regarding an impact-resistant thermoplastic resin composition with increased heat resistance by blending polyglutarimide with a high heat distortion temperature and a rubbery polymer. (Unexamined Japanese Patent Publication No. 58-83055,
58-83056, JP 58-83057, JP 58-83058). However, this polyglutarimide (However, in the formula, R ₁ , R ₂ , and R ₃ each represent hydrogen or a substituted or unsubstituted alkyl group or aryl group having 1 to 20 carbon atoms.) Although it is a polymer, its composition and molecular weight are not clear, and its compatibility with rubber-like polymers cannot be said to be good. (Problems to be Solved by the Invention) An object of the present invention is to obtain an ABS resin composition with excellent heat resistance, and to improve the compatibility between a copolymer having a six-membered ring structural unit and an ABS resin. The goal is to achieve that goal by improving. (Means for Solving the Problems) In order to achieve the above object, the present inventors have conducted studies and found that the composition of a copolymer containing a six-membered ring structural unit has been devised. The inventors have discovered that they can be better blended with ABS resin by using the method, and have completed the present invention based on this knowledge. That is, the present invention provides methyl methacrylate units
20-95 mol%, general formula (R in the formula is a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group)
A total of 3 to 78 mol% of six-membered ring structural units represented by formula (1), 0.1 to 50 mol% of acid anhydride units of formula (2), 2 to 77 mol% of imide units of formula (2), and aromatic vinyl units. 1~
The viscosity of a methyl ethyl ketone solution containing 70 mol% and 1 to 20 mol% of methacrylic acid units and a 10% by weight copolymer concentration at a temperature of 25°C is 3 to 20%.
50 to 98% by weight of copolymer (A) that is centipoise;
1 to 49% by weight of copolymer (B) consisting of 34 to 82 mol% of aromatic vinyl units and 18 to 66 mol% of unsaturated nitrile units, and aromatic vinyl units in a rubber having a glass transition temperature of -30°C or lower. The present invention relates to a heat-resistant resin composition comprising a copolymer containing 34 to 82 mol % and 18 to 66 mol % of unsaturated nitrile units, and 1 to 49 mol % of graft rubber (C). A feature of the resin composition of the present invention is that two types of copolymers and one type of copolymer graft rubber are well compatible with each other, thereby obtaining a resin composition with excellent heat resistance and impact resistance. There is a particular thing. The copolymer (A) constituting the resin composition of the present invention has excellent heat resistance and has a high heat distortion temperature and a high thermal decomposition temperature, and is mainly composed of methyl methacrylate units, six-membered cyclic acid anhydrides, and six-membered cyclic imide units. It also contains necessary amounts of aromatic vinyl units and methacrylic acid units. The methyl methacrylate unit that makes up this copolymer (A) has the effect of exhibiting oil resistance and strength.
95 mol% is required, but preferably 25 to 90 mol%. If it is less than 20 mol%, the strength and oil resistance of the copolymer (A) will be insufficient, and the resin composition will also have insufficient impact resistance, which is not preferable. The six-membered ring structural unit constituting the copolymer (A) consists of the following formulas (1) and (2). (In the formula, R is a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, or an aracyl group.) All of them play a role in increasing heat resistance, and their content is 3 to 78 mol%, preferably, It is 5 to 50 mol%. If it is less than 3 mol %, there is no effect of improving heat resistance, and if it exceeds 78 mol %, the melt flowability of the resin composition will decrease, which is not preferable because molding processability will decrease. This six-membered ring structural unit is a six-membered ring acid anhydride unit.
0.1 to 50 mol% and 2 to 77 mol% of six-membered ring imide units
Preferably, the main component is six-membered cyclic imide units, and 0.1 to 10 six-membered cyclic acid anhydride units.
mol%, and the six-membered ring imide unit is 4 to 50 mol%
It is. Although the six-membered ring imide unit is excellent in terms of heat resistance and water resistance, it is another component that prevents a decrease in melt fluidity and constitutes the resin composition. A six-membered cyclic acid anhydride unit is necessary to maintain good compatibility with the unsaturated nitrile-containing copolymer. Copolymer (A)
The aromatic vinyl units constituting this have the effect of maintaining high melt fluidity and keeping hygroscopicity low.
mol %, preferably 5 to 50 mol %. If it is less than 1 mole, the melt fluidity will be greatly reduced and the hygroscopicity will also be large, which is not preferable. On the other hand, if it exceeds 70 mol%, mechanical strength decreases, which is not preferable. Examples of the aromatic vinyl constituting this copolymer (A) include styrene, α-methylstyrene, P-methylstyrene, chlorostyrene, p-tert-butylstyrene, etc.;
- Preferably used in combination with methylstyrene. The methacrylic acid unit constituting the copolymer (A) plays the role of improving heat resistance together with the six-membered ring structural unit, and is in the range of 1 to 20 mol%, preferably 1 to 15 mol%. be. If it is less than 1 mol %, it cannot play a role in improving heat resistance, and if it exceeds 20 mol %, it becomes highly thermally decomposable, and when the resin composition is molded at 260° C. or higher, gas is generated, which is not preferable. This copolymer (A) requires an appropriate molecular weight. One way to express this molecular weight is concentration
Using the viscosity of a 10% by weight methyl ethyl ketone solution at a temperature of 25 DEG C., it is not preferred for the composition unless it is 3 to 20 centipoise, preferably 30 to 10 centipoise. When it is less than 3 centipoise, the impact resistance of the composition decreases, which is undesirable. On the other hand, when it exceeds 20 centipoise, the melt flowability of the composition decreases, resulting in poor moldability. The six-membered ring structural unit of copolymer (A) is obtained by converting most of the six-membered cyclic acid anhydride units into imide units; Ammonia, aliphatic primary amines, aromatic amines, etc. are used for modification. As the ammonia, dissolved ammonia, ammonia gas, or aqueous ammonia can be used, and as the aliphatic primary amine, for example, methylamine, ethylamine, n-propylamine, iso-propylamine, tert-butylamine, pentylamine. , hexylamine, cyclohexylamine, allylamine, etc., and these can also be used as an aqueous solution. Examples of aromatic amines include aniline, o-toluidine, p-toluidine, o-chloroaniline, p-chloroaniline, 2,4,6-trichloroaniline, α-naphthylamine, β-naphthylamine, and the like. Benzylamine, DL-, D- or L-
α-phenethylamine, β-phenethylamine, etc. can also be used. Furthermore, polyamines such as 2-diethylaminoethylamine and hydroxylamines such as isopropanolamine can also be used. Next, various methods can be used to modify the six-membered cyclic acid anhydride unit into the six-membered cyclic imide unit. For example, a copolymer containing a six-membered cyclic acid anhydride unit is charged as a reaction precursor in an autoclave, then aqueous ammonia is injected in a solution state to react, and the imide is further treated at a temperature of 250°C for 2 hours. Alternatively, the precursor copolymer is continuously melted using an extruder, and then aqueous ammonia, cyclohexylamine, aniline, etc. are continuously injected, and then cyclized to imide in a vacuum chamber. etc. are used. The copolymer (B) and the graft copolymer in the graft rubber (C) are copolymers of aromatic vinyl and unsaturated nitrile. The aromatic vinyl unit is required to be 34 mol% or more to maintain melt fluidity, and the unsaturated nitrile unit has high strength and impact resistance, and has good compatibility with the copolymer (A). 18 mol% to improve
The above is necessary. The aromatic vinyl constituting this copolymer includes styrene, α-methylstyrene, p-methylstyrene, chlorostyrene, p-
Examples include tert-butylstyrene, but styrene or α-methylstyrene alone or styrene and α-methylstyrene can be used.
- Preferably used in combination with methylstyrene. Examples of unsaturated nitriles include acrylonitrile and methacrylonitrile, with acrylonitrile being preferred. The graft rubber (C) has the effect of developing impact resistance of the resin composition. Graft rubber consists of a graft copolymer and rubber, both of which are
The weight ratio is 0.2≦graft copolymer/rubber≦1. Grafted rubber outside the above range cannot improve impact resistance. Rubber is-
If it has a glass transition temperature of 30°C or less, and if it exceeds -30°C, it will be impossible to exhibit high impact resistance. Examples of this rubber include polybutadiene, butadiene copolymers containing 60% by weight or more of butadiene and 40% by weight or less of other copolymerizable monomers, alkyl acrylate polymers, ethylene-propylene terpolymers, etc. Particularly common are polybutadiene and butadiene copolymers. In the case of this butadiene copolymer, monomers copolymerizable with butadiene include:
These include aromatic vinyl, unsaturated nitriles, and unsaturated carboxylic acids. In this case, the aromatic vinyl used is styrene, α-methylstyrene, or p-methylstyrene, with styrene being particularly common.
Examples of unsaturated nitriles include acrylonitrile and methacrylonitrile, with acrylonitrile being preferred. The unsaturated carboxylic acid is generally methacrylic acid, but its content is often 5% by weight or less. Next, copolymer (A), copolymer (B) and graft rubber
Indicates the amount of (C) mixed. The copolymer (A) is in the range of 50 to 98% by weight, preferably 50 to 85% by weight. If it is less than 50% by weight, heat resistance will decrease, and if it exceeds 98% by weight, it will become highly rigid and impact resistance will decrease, which is not preferable. The amount of copolymer (B) is in the range of 1 to 49% by weight, preferably 5 to 40% by weight. If it is less than 1% by weight, the copolymer (A) and the graft rubber (C) cannot be intimately mixed with each other, resulting in a decrease in impact resistance, and if it exceeds 49% by weight, the copolymer (A) and the graft rubber ( The amount of C) decreases and the balance between heat resistance and impact resistance decreases, both of which are unfavorable. The amount of graft rubber (C) is in the range of 1 to 49% by weight, preferably 10 to 45% by weight. If it is less than 1% by weight, the impact resistance will decrease, and if it exceeds 49% by weight, the rigidity of the resin composition will decrease and the practical heat distortion temperature will decrease. Blending of the copolymers (A), (B) and the graft rubber (C) is usually carried out using an extruder, but a twin-screw extruder is particularly preferred. Regarding the copolymer (A), first, a terpolymer of methyl methacrylate-aromatic vinyl-methacrylic acid is obtained by radical copolymerization. In this case, the polymerization method may be bulk polymerization, solution polymerization, or suspension polymerization. This ternary copolymer is then treated at high temperature and reduced pressure to generate six-membered cyclic acid anhydride units to form four elements of methyl methacrylate-aromatic vinyl-methacrylic acid-six-membered cyclic acid anhydride, and further, A part or most of the six-membered cyclic acid anhydride is modified into a six-membered cyclic imide by the action of ammonia or various primary amines. Copolymer (B) is obtained by radical copolymerization. In this case, the polymerization method is bulk polymerization, solution polymerization, suspension polymerization,
Either emulsion polymerization may be used. Graft rubber (C) is produced by radical polymerization of aromatic vinyl and unsaturated nitrile in the presence of rubber, including bulk polymerization, solution polymerization, bulk polymerization, suspension two-stage polymerization,
Although any polymerization method including emulsion polymerization may be used, emulsion polymerization is more commonly used. The composition thus obtained can be provided as is for injection molding or extrusion molding, but
If necessary, various heat stabilizers, benzotriazole type, hindered amine type light stabilizers, etc. may be added during blending, and nonionic surfactants and anionic surfactants may also be added. Sometimes. Furthermore, as a lubricant, liquid paraffin, _C8 - _C22 higher fatty acids, metal salts of _C4 - _C22 higher fatty acids (calcium, magnesium, zinc, etc.), ethylene bis fatty acid ( _C16 , _C18 ) amide,
Higher aliphatic alcohols such as stearyl alcohol, dibutyl or dioctyl esters of adipic acid and sebacic acid, higher fatty acids ( _C8 to _C22 ),
Di, triglycerides, hydrogenated castor oil, hydrogenated beef tallow,
Dimethylpolysiloxane or the like may also be added. (Effects of the Invention) According to the present invention, an impact-resistant resin composition with excellent heat resistance can be obtained. The composition is suitably used in various applications such as automobile parts, industrial parts, and home appliance parts. (Example) Next, the present invention will be explained in more detail with reference to Examples. The measurement method for each physical property is as follows. (1) Vikatsu softening temperature: ASTM-D1525 (2) Heating deformation temperature (18.4Kg/cm ² , 1/4 inch,
(No annealing): ASTM-D648 (3) Izot impact strength: ASTM-D256 (1/
(4 inches, notched) (4) Tensile strength: ASTM-D638 (5) Tensile elongation: ASTM-D638 (6) Solution viscosity: Copolymer in methyl ethyl ketone
Solution viscosity at 25°C with 10% concentration by weight. A Canon Fuensti type viscosity tube (#200) was used. (i) Production of copolymer (A) 28 parts by weight of methyl methacrylate, 13 parts by weight of styrene, 24 parts by weight of methacrylic acid, 35 parts by weight of ethylene glycol monoethyl ether For a total of 100 parts by weight, 0.1 part by weight of octyl mercaptan, 1,1-
Jeter Shiary Butyl Peroxy-3,3,5
-A mixed solution was prepared by adding 0.01 part by weight of trimethylcyclohexane. This mixed solution was continuously fed to a complete mixing type gravimeter at 112° C. for polymerization. A polymerization reaction solution with a solid content of 42% by weight was continuously supplied to a high temperature vacuum chamber to remove unreacted substances and solvent and to produce a six-membered cyclic acid anhydride. The styrene content was determined by ultraviolet absorbance, the amount of methyl methacrylate and six-membered cyclic acid anhydride was determined by infrared spectrophotometry, and the amount of methacrylic acid was determined by titration.The results showed that methyl methacrylate units were 34 mol% and styrene units were 28 mol%. Mol%, 6-membered cyclic acid anhydride unit 27 mol%, methacrylic acid unit 11
It was in mol%. Also, 10 of this copolymer (A) precursor
The viscosity of methyl ethyl ketone solution at 25℃ is
It was 5.5 centipoise. First, Table 1 shows the properties of the precursor of the copolymer (A) having six-membered cyclic acid anhydride units. Next, this precursor and methyl ethyl ketone were charged into an autoclave to form a 20% by weight solution. Next, 2 equivalents of aniline was added to the six-membered cyclic acid anhydride unit amount of this copolymer, and the mixture was heated at 150°C for 20 minutes.
Time processed. After taking out the reaction solution, the polymer was precipitated with n-hexane, and after purification, this polymer was
The treatment was carried out at 250°C for 2 hours in a 10 torr volatilization furnace.
The final product was almost colorless and transparent. Measurement using an infrared spectrophotometer showed that the absorption of the six-membered ring acid anhydride decreased considerably, and at the same time, the formation of a new six-membered ring imide at 1680 cm ^-1 was observed. From the nitrogen content in elemental analysis, 25 mol% of six-membered ring imide units,
The six-membered cyclic acid anhydride units were 2 mol %, so the imidization rate was 93%. The properties of the copolymer (A) thus obtained are shown in Table 1.

[Table] (ii) Production of copolymer (B) Styrene, acrylonitrile, and ethylbenzene are continuously fed into a complete mixing reactor. The polymerization temperature is
The temperature is set at 100-150℃, the polymerization rate is 30-50% by weight, the reactor is led to a high-temperature vacuum chamber, residual monomers and solvent are removed, and then extruded using an extruder to form styrene units.
A copolymer (B) containing 54 mol% and 46 mol% of acrylonitrile units was obtained. (iii) Production of graft rubber (C) Polyptadiene latex converted to solid content
A mixture of 35 parts by weight of styrene and 15 parts by weight of acrylonitrile and 0.5 parts by weight of potassium persulfate were added to 50 parts by weight of ion-exchanged water at 70°C under stirring. Polymerization was carried out while adding an aqueous solution dissolved in
After the polymerization reaction was completed, the graft copolymer latex was salted out, dehydrated, dried, and granulated to obtain a pellet-like graft copolymer. The graft copolymer thus obtained is a mixture of components (B) and (C). When the insoluble and soluble components were separated using acetone, 75 parts by weight of the rubber component was 75 parts by weight, that is, the graft copolymer. Grafting rate
It will be 50%. On the other hand, the acetone soluble content was 25 parts by weight, and it was a styrene-acrylonitrile copolymer (B) containing 46 mol% of acrylonitrile units and 54 mol% of styrene units. Hereinafter, when mixing each component, component (B) and component (C) in the graft copolymer were separated. Examples 1 to 4 and Comparative Examples 1 to 4 Using the copolymers (A), (B) and graft rubber (C) produced in (i), (ii), and (iii) above, the samples shown in Table 2 were used. They were mixed in the same proportions and granulated using a twin-screw extruder to obtain a pellet-shaped blended resin composition. Thereafter, this pellet-like resin composition was sufficiently dried, and molded pieces for physical property tests were injection molded. After leaving this molded piece under conditions of 23° C. and 50% humidity for 48 hours, its physical properties were measured. The results are shown in Table 2.

【table】

Claims (1)

[Claims] 1. 20 to 95 mol% of methyl methacrylate units, general formula (In the formula, R is a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, or an aralkyl group). unit 0.1 to 50 mol%, imide unit of formula (2) 2 to 77 mol%, aromatic vinyl unit 1 to
The viscosity of a methyl ethyl ketone solution containing 70 mol% and 1 to 20 mol% of methacrylic acid units and a 10% by weight copolymer concentration at a temperature of 25°C is 3 to 20%.
50 to 98% by weight of copolymer (A) that is centipoise;
1 to 49% by weight of a copolymer (B) consisting of 34 to 82 mol% of aromatic vinyl units and 18 to 66 mol% of unsaturated nitrile units, and aromatic vinyl units in a rubber having a glass transition temperature of -30°C or lower. A heat-resistant resin composition comprising 1 to 49% by weight of a graft rubber (C) grafted with a copolymer comprising 34 to 82 mol% and 18 to 66 mol% of unsaturated nitrile units.