JPS6345740B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a thermoplastic resin composition that has a high heat distortion temperature and a high thermal decomposition temperature, and has excellent impact resistance. Many studies have been conducted to improve the heat resistance of vinyl polymers. For example, copolymers made by copolymerizing maleimide monomers with vinyl monomers such as styrene have high heat distortion temperatures and heat resistance. It is known to have a decomposition temperature (Kobunshi Saishu, Vol. 36, No. 7, p. 447, published in 1979)
However, mechanical properties such as impact resistance are inferior (L.
E. Coleman et al, J. Polymer Sci. No. 38, No.
(p. 241, published in 1959), and maleimide monomers such as N-phenylmaleimide have disadvantages in that the synthesis method is not simple and it is difficult to obtain them at low cost. Therefore, as a method for obtaining a maleimide copolymer without using a maleimide monomer as a starting material,
For example, a method has been proposed in which a copolymer of styrene and maleic anhydride is reacted with ammonia or a primary amine to convert the maleic anhydride units into maleimide units (Japanese Patent Publication No. 39651/1983). Maleimide copolymers obtained by this method also have the disadvantage of low impact strength. Therefore, in order to improve the above drawbacks, a graft copolymer based on a rubbery polymer is blended with a maleimide copolymer obtained by reacting a maleic anhydride copolymer with ammonia or a primary amine. compositions have been proposed (U.S. Patent No.
3642949 and JP-A-57-125241). However, compositions made of maleimide copolymers and graft copolymers do not have sufficient impact strength, and when other thermoplastic resins are added to improve impact strength, the heat distortion temperature decreases. . Therefore, the present inventors conducted extensive studies with the aim of obtaining a thermoplastic molding material with excellent thermal deformation temperature and impact strength, and as a result, they imidized a maleic anhydride copolymer with a specific copolymer composition. We have discovered that the above object can be effectively achieved by blending the obtained maleimide copolymer, a specific graft copolymer, and a specific vinyl (co)polymer in a specific ratio, and have arrived at the present invention. . That is, the present invention provides (A) a maleic anhydride copolymer obtained by copolymerizing 45 to 55 mol% of styrene and/or α-methylstyrene and 45 to 55 mol% of maleic anhydride to ammonia or a primary amine. Maleimide copolymer obtained by reacting with 20~
A monomer mixture consisting of styrene and at least one other vinyl monomer capable of copolymerizing styrene in the presence of 90 parts by weight and 20 to 80% by weight of (B) a rubbery polymer.
40 to 5 parts by weight of a graft copolymer obtained by graft polymerization of 80 to 20% by weight, and (C) an aromatic vinyl monomer, a vinyl cyanide monomer, and a (meth)acrylic acid ester monomer A vinyl (co)polymer obtained by (co)polymerizing at least one selected from
A thermoplastic resin composition is provided in which 40 to 5 parts by weight of (A), (B) and (C) are blended so that the total amount is 100 parts by weight. The composition of the present invention contains a maleimide copolymer (A) obtained by imidizing a maleic anhydride copolymer having a specific copolymer composition, a graft polymer, and a specific copolymer in a specific ratio. It is characterized by its combination. That is, in the present invention, the maleic anhydride content in the maleic anhydride copolymer is set relatively high, and this is highly imidized to produce a maleimide copolymer with an extremely high heat distortion temperature.
By blending (A) with the other two components (B) and (C) in a specific proportion, especially in a high proportion of the vinyl (co)polymer, grafting with the maleimide copolymer (A) can be achieved. The affinity of the copolymer (B) is significantly improved, and a composition with extremely improved impact strength and fluidity can be obtained while maintaining a high heat distortion temperature. The maleimide copolymer (A) used in the present invention is
45-55 mol% maleic anhydride and styrene and/or
Alternatively, a maleic anhydride copolymer obtained by copolymerizing 45 to 55 mol% of α-methylstyrene is reacted with ammonia or a primary amine to convert maleic anhydride units into maleimide units. A copolymer. The content of maleic anhydride in the maleic anhydride copolymer used here is important; if it is less than 45 mol%, the heat distortion temperature of the maleimide copolymer obtained by imidization will not be sufficient; %, it is not preferable because it is difficult to obtain a copolymer having alternating copolymerizability. This maleimide copolymer (A) is
As described in the publication, it can also be obtained by reacting a maleic anhydride-based copolymer with ammonia or amine in an aqueous suspension, or it can be obtained by non-containing methods such as a solution, suspension in a hydrocarbon, or bulk melting. It can also be obtained by reaction with ammonia or primary amines in the aqueous state. Among them, in organic solvents, 0 to 75
React with ammonia or primary amine at °C,
A preferred method is to perform imide ring closure by heating after removing the solvent. The primary amines used here include methylamine, ethylamine,
n-propylamine, isopropylamine, n-
Butylamine, t-butylamine, aniline, p
-Chloraniline, naphthylamine, etc., among them isopropylamine, aniline, p-
Preference is given to using chloraniline. The graft copolymer (B) used in the present invention is composed of at least one of the above-mentioned aromatic vinyl monomer and another vinyl monomer copolymerizable therewith in the presence of a rubbery polymer. It is formed by polymerizing a monomer mixture, and other vinyl monomers here include vinyl cyanide monomers represented by acrylonitrile, methacrylonitrile, etc., methyl methacrylate, acrylic acid, etc. These include (meth)acrylic acid ester monomers such as ethyl. Here, examples of the rubbery polymer include diene rubbers such as polyptadiene rubber, acrylonitrile-butadiene copolymer rubber (NBR), styrene-butadiene copolymer rubber (SBR), polybutyl acrylate, polypropyl acrylate, etc. Acrylic rubber and ethylene-propylene-diene rubber (EPDM) can be used. In the graft copolymer (B), the ratio of the monomer mixture of the rubbery polymer, the aromatic vinyl monomer, and other vinyl monomers that can be copolymerized with the rubbery polymer is 20 to 20%. 80% by weight, especially 30-70% by weight of said monomer mixture 80-20% by weight, especially 70-70% by weight
It is necessary to polymerize 30% by weight. If the proportion of the rubbery polymer is less than 20% by weight, the resulting composition will not have sufficient impact resistance, and if it exceeds 80% by weight, not only will the mechanical strength of the resulting composition decrease, but the gloss etc. It is undesirable because it gives an unfavorable result to the appearance of the product. Note that these graft copolymers (B) are produced by known polymerization methods such as emulsion polymerization, bulk polymerization, and bulk-suspension polymerization. The vinyl (co)polymer (C) used in the present invention is
It is a (co)polymer formed by (co)polymerizing at least one vinyl monomer that is the graft component of the graft copolymer (B), such as polystyrene, styrene-acrylonitrile copolymer, styrene- Examples include methyl methacrylate copolymer and styrene-acrylonitrile-methyl methacrylate copolymer. These vinyl (co)polymers (C) are produced by known polymerization methods such as emulsion polymerization, suspension polymerization, bulk polymerization, and solution polymerization. The resin composition of the present invention is obtained by blending the maleimide copolymer (A), the graft copolymer (B), and the vinyl (co)polymer (C). The blending ratio is 20 to 90 parts by weight of (A), especially 30 to 80 parts by weight, and 40 to 5 parts by weight of (B), especially 35 to 10 parts by weight.
Parts by weight, (C) is selected from a range of 40 to 5 parts by weight, particularly 35 to 10 parts by weight (total 100 parts by weight). If the amount of the maleimide copolymer (A) is less than 20 parts by weight, only a composition with an extremely low heat distortion temperature will be obtained, and if it exceeds 90 parts by weight, the impact resistance of the composition will decrease, which is not preferable. . Also, graft copolymer (B)
If the amount is less than 5 parts by weight, the impact resistance will be insufficient, and if it exceeds 40 parts by weight, the heat distortion temperature will drop significantly. Furthermore, if the amount of the vinyl (co)polymer (C) is less than 5 parts by weight, the impact resistance will be insufficient, and if it exceeds 40 parts by weight, the heat distortion temperature will drop significantly, which is not preferable. There are no particular restrictions on the method of blending the maleimide copolymer (A), graft copolymer (B), and vinyl (co)polymer (C). A method is adopted in which the components are first supplied to an extruder in a desired ratio and melt-mixed. In addition, an antioxidant such as a normal hindered phenol antioxidant, a phosphorus antioxidant, and a sulfur antioxidant may be added to the thermoplastic resin composition of the present invention to improve thermal stability. A lubricant can also be added to further improve fluidity. Further, fiber reinforcing agents such as glass fibers, inorganic fillers, colorants, pigments, conductive materials, etc. can also be blended depending on the purpose. Furthermore, flame retardation can be achieved by mixing general halogenated organic compound flame retardants such as tetrabromobisphenol A, decabromophenyl ether, and brominated polycarbonate with antimony oxide into the resin composition of the present invention. . As explained above, the thermoplastic resin composition of the present invention has well-balanced and excellent heat resistance, represented by heat distortion temperature, and mechanical properties, represented by impact strength. It is expected to be applied to various uses. The present invention will be further explained below using reference examples and examples. In addition, the heat distortion temperature in the reference examples and examples is ASTM D648-56, and the Vikatsu softening temperature is
JIS K6870, Izot impact value is ASTM D256-
56Method A. In addition, the number of parts means parts by weight, and the number of parts means percent by weight. Reference Example 1 [Preparation of maleimide copolymer (A-1)] Internal volume equipped with a reflux condenser and a stirrer
3.2Kg of styrene and maleic anhydride in 20 polymerization tanks
2.8 kg, methyl ethyl ketone (solvent) 9 kg, and benzoyl peroxide (initiator) 18 g were charged and sufficiently dissolved. Then, while stirring, the temperature inside the polymerization tank was raised to 75%.
℃ and polymerized for 5 hours. After that, the temperature inside the polymerization tank was lowered to 30℃, and the polymerization rate was measured by gas chromatography, and it was 99.5%, and no unreacted maleic anhydride was detected, indicating that the maleic anhydride content in the copolymer was 48.4 mol%. Next, 2.7 kg of reaction hair aniline was added, and stirring was continued for 30 minutes while maintaining the temperature at 30°C. Thereafter, the reaction solution was dropped into toluene to remove methyl ethyl ketone and unreacted styrene, and then dried to obtain a pale and colored copolymer. This copolymer was extruded at 270°C using a vented extruder.
As a result of kneading for 15 minutes and carrying out a dehydrated imide ring-closing reaction, 8.5 kg of maleimide copolymer (A-1) containing 61% N-phenylmaleimide was obtained.
Its Vikatsu softening temperature was 200°C. Reference Example 2 [Preparation of maleimide copolymer (A-2)] In the same polymerization tank as in Reference Example 1, 3.1 kg of styrene, 2.9 kg of maleic anhydride, and methyl ethyl ketone (solvent) were added.
9 kg and 18 g of benzoyl peroxide (initiator) were charged and sufficiently dissolved. Then, while stirring, the temperature inside the polymerization tank was
The temperature was raised to 75°C and polymerization was carried out for 5 hours. After that, the temperature inside the polymerization tank was lowered to 30℃, and the polymerization rate was measured by gas chromatography, and it was 99.2%, and no unreacted maleic anhydride was detected, indicating the maleic anhydride content in the copolymer. was 49.8 mol%. Next, 2.8 kg of reaction hair aniline was added, and stirring was continued for 30 minutes while maintaining the temperature at 30°C. Thereafter, the reaction solution was taken out into a tray, air-dried, and then vacuum-dried to remove methyl ethyl ketone and unreacted styrene to obtain a pale and colored copolymer. This copolymer was extruded at 270°C using a vented extruder.
As a result, 8.8 kg of maleimide copolymer (A-2) containing 62% N-phenylmaleimide was obtained, and its Vikato softening temperature was 210°C. It was hot. Reference Example 3 [Preparation of maleimide copolymer (A')] 5 kg of styrene, 2.5 kg of methyl ethyl ketone (solvent), and benzoyl peroxide (initiator) were placed in a polymerization tank with an internal volume of 20 equipped with a reflux condenser, a stirrer, and a dropping funnel. ) 35g was charged and sufficiently dissolved. Separately, a solution of 40% maleic anhydride in methyl ethyl ketone was prepared and charged into the dropping funnel. Next, while keeping the temperature inside the polymerization tank at 75℃ and stirring,
A maleic anhydride-methyl ethyl ketone solution was added from the dropping funnel at a rate of 833 g/hr for 3 hours, and after the addition was completed, it was maintained for 2 hours. After that, the temperature inside the polymerization tank was cooled to 30°C, and the polymerization rate was measured by gas chromatography, and it was 94%, and no unreacted maleic anhydride was detected, indicating the maleic anhydride content in the copolymer. was 18.6 mol%. Next, 950 g of reactive hair aniline was added, and stirring was continued for 30 minutes while maintaining the temperature at 30°C. Thereafter, the reaction solution was taken out into a tray, air-dried, and then vacuum-dried to remove methyl ethyl ketone and unreacted styrene to obtain a pale and colored copolymer. This copolymer was extruded at 270°C using a vented extruder.
As a result of kneading for 15 minutes and carrying out a dehydrated imide ring-closing reaction, 6.4 kg of a maleimide copolymer (A') containing 28% N-phenylmaleimide was obtained, and its Vikato softening temperature was 160°C. Ta. Reference Example 4 [Preparation of maleimide copolymer (A-3)] Internal volume equipped with a reflux condenser and a stirrer
0.5 kg of styrene, 2.7 kg of α-methylstyrene, 2.8 kg of maleic anhydride, 9 kg of methyl ethyl ketone (solvent), and 18 g of benzoyl peroxide (initiator) were charged into a polymerization tank No. 20 and sufficiently dissolved. Then, while stirring, the temperature inside the polymerization tank was raised to 75%.
℃ and polymerized for 8 hours. After that, the temperature inside the polymerization tank was lowered to 30℃, and the polymerization rate was measured by gas chromatography, and it was 99.3%, and no unreacted maleic anhydride was detected, so the maleic anhydride content of the copolymer was It was 50.9 mol%. Next, 2.7 kg of reaction hair aniline was added, and stirring was continued for 30 minutes while maintaining the temperature at 30°C. Thereafter, the reaction solution was dropped into toluene to remove methyl ethyl ketone and unreacted styrene, and then dried to obtain a pale and colored copolymer. This copolymer was extruded at 270°C using a vented extruder.
As a result of kneading for 15 minutes and carrying out a dehydrated imide ring-closing reaction, 8.2 kg of maleimide copolymer (A-4) containing 63% N-phenylmaleimide was obtained.
Its Vikatsu softening temperature was 212°C. Example Maleimide copolymers (A-1, A-2, A', A-3) prepared in Reference Examples 1 to 4 were mixed with a rubber content of 60
% styrene-acrylonitrile-butadiene graft copolymer (ABS) and styrene-acrylonitrile copolymer (SAN) containing 28% acrylonitrile in the proportions shown in Table 1, and after melt extrusion using an extruder, injection molding was performed. The physical properties of the test pieces were measured. The measurement results of heat distortion temperature and Izot impact strength are shown in Table 1 along with the blending ratio.

[Table] As is clear from Table 1, the resin compositions of the present invention (Nos. 1 to 4) have excellent thermal deformation temperature and Izot impact strength that are well balanced. On the other hand, when the copolymer (C) was not blended (No. 5), when the blending ratio was off (No. 6), and when the copolymer with the maleic anhydride content was off, the results were obtained by imidizing the copolymer. When using maleimide copolymer (A') (No. 7,
In case 8), only a composition can be obtained which is insufficient in either the heat distortion temperature or the Izod impact strength.

Claims (1)

[Claims] 1 (A) A maleic anhydride copolymer prepared by copolymerizing 45 to 55 mol% of styrene and/or α-methylstyrene and 45 to 55 mol% of maleic anhydride is reacted with ammonia or a primary amine. An aromatic vinyl monomer and other vinyl monomers copolymerizable with it in the presence of 20 to 90 parts by weight of the resulting maleimide copolymer and 20 to 80 weight % of the (B) rubbery polymer. A monomer mixture consisting of at least one of: 80~
40 to 5 parts by weight of a graft copolymer obtained by graft polymerizing 20% by weight, and (C) an aromatic vinyl monomer,
Vinyl (co)polymer 40-40 formed by (co)polymerizing at least one selected from vinyl cyanide monomers and (meth)acrylic acid ester monomers
A thermoplastic resin composition containing 5 parts by weight of (A), (B) and (C) such that the total is 100 parts by weight.