JPH0379386B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention contains a copolymer obtained by aqueous emulsion polymerization of an aromatic vinyl monomer, a vinyl cyanide monomer, and a vinyl monomer copolymerizable with these, and an ABS resin and/or an AS resin. This invention relates to a thermoplastic resin composition with significantly improved color tone, impact resistance, and heat resistance. Conventionally, when polymerizing a monomer mixture containing aromatic vinyl monomers and vinyl cyanide monomers as main components, vinyl cyanide monomers and/or
Alternatively, there is a method of adding an aromatic vinyl monomer and polymerizing it to obtain a copolymer. (Tokuko Showa 45-33661
(Japanese Patent Publication No. 47-46472) However, the copolymers obtained by these methods have a distribution in molecular weight and monomer composition, resulting in copolymers with poor color tone, impact resistance, and heat resistance. Therefore, even if this is blended with ABS resin and/or AS resin, a thermoplastic resin composition with sufficient color tone, impact resistance, and heat resistance cannot be obtained. In particular, when a copolymer in which vinyl cyanide monomer is added alone in the late stage of polymerization is blended with ABS resin and/or AB resin, the color tone deteriorates significantly and the impact resistance and heat resistance also decrease. There is. As a result of intensive studies to improve these drawbacks, the inventors of the present invention have developed a copolymer and a graft polymer in which vinyl cyanide monomer is added to the polymerization system at a controlled rate from the initial stage of polymerization to complete the polymerization. copolymer and/or
The present invention has also been accomplished by discovering a thermoplastic resin composition containing a suspension polymerized or bulk polymerized copolymer as a main component and having significantly improved color tone, impact resistance, and heat resistance. In the present invention, component (a) is an aromatic vinyl monomer of 65 to 80%
A copolymer obtained by aqueous emulsion polymerization of 15-30% by weight of vinyl cyanide monomer and 0-20% by weight of vinyl monomer copolymerizable with these, in which the aromatic vinyl monomer is The entire amount of the vinyl cyanide monomer is present at the start of polymerization, and a portion of the vinyl cyanide monomer is present at the start of polymerization to initiate polymerization, and the remaining vinyl cyanide monomer is added between the start and the end of polymerization. It is added to the polymerization system at a rate substantially slower than the polymerization rate of the aromatic vinyl monomer, and the polymerization rate is 0 to 90%.
The composition ratio of unreacted monomers in the polymerization system is such that the total number of moles of aromatic vinyl monomer and the copolymerizable vinyl monomer is greater than the number of moles of vinyl cyanide monomer. 20 to 85 parts by weight of a copolymer that has been maintained at 1.3 to 3 times the polymerization to substantially complete the polymerization, and 30 to 80 parts by weight of a rubbery polymer whose component (b) has a glass transition temperature of 0°C or lower. 20-70 parts by weight of a monomer mixture consisting of 50-80% by weight of aromatic vinyl monomers, 15-35% by weight of vinyl cyanide monomers, and 0-30% by weight of vinyl monomers copolymerizable with these. 10 to 50 parts by weight of a copolymer grafted with Component (c) is 50 to 80% by weight of aromatic vinyl monomer and 15 to 15 parts by weight of vinyl cyanide monomer.
This is a thermoplastic resin composition comprising 0 to 50 parts by weight of a polymer obtained by copolymerizing a monomer mixture consisting of 35 parts by weight and 0 to 30 parts by weight of a vinyl monomer copolymerizable with these. The present invention will be further explained in detail below. In the resin composition of the present invention, the method for producing the copolymer of component (a) is important, and the aromatic vinyl monomer is present in the entire amount used at the start of polymerization;
Then, a part of the vinyl cyanide monomer to be used is present at the beginning of the polymerization to initiate the polymerization, and the remaining vinyl cyanide monomer is added to the polymerization system from the beginning to the end of the polymerization. When the polymerization rate is between 0 and 90%, the composition ratio of unreacted monomers in the polymerization system is
The total number of moles of the aromatic vinyl monomer and the copolymerizable vinyl monomer is kept at 1.3 to 3 times, particularly preferably 1.7 to 2.5 times, relative to the number of moles of the vinyl cyanide monomer to substantially carry out the polymerization. A copolymer made by completing the process is used. If the number of moles exceeds 3 times the unreacted vinyl cyanide monomer, it is difficult to obtain a high molecular weight polymer, and compositions using this have poor impact resistance and heat resistance; A composition using a polymer obtained when the number of moles is less than 1.3 times that of the vinyl monomer has a marked deterioration in color tone and a decrease in heat resistance and impact resistance. In addition, the aromatic vinyl monomers that are constituents of the copolymer of component (a) include α-methylstyrene (hereinafter abbreviated as αMSM), vinyltoluene, t-butylstyrene, halogen-substituted styrene, and styrene (hereinafter abbreviated as αMSM).
αMSM and mixtures thereof are particularly preferred. Examples of vinyl cyanide monomers include acrylonitrile (hereinafter abbreviated as AN), methacrylonitrile, and α-
Examples include chloroacrylonitrile, but AN is particularly preferred. Specific examples of vinyl monomers copolymerizable with aromatic vinyl monomers and vinyl cyanide monomers include acenaphthylene, fumaronitrile, maleimide, N-substituted maleimide, methacrylic acid, acrylic acid, methacrylic acid ester, and acrylic acid. One or more types selected from various known vinyl monomers such as acid esters. The entire amount of these copolymerizable vinyl monomers may be present at the beginning of the polymerization, or, if desired, the entire amount or a portion thereof may be added to the polymerization system during the polymerization. Next, examples of the aromatic vinyl monomer that is a constituent component of the graft copolymer of component (b) include SM, αMSM, vinyltoluene, t-butylstyrene, halogen-substituted styrene, and mixtures thereof, particularly SM and Mixtures thereof are preferred. Vinyl cyanide monomers include AN, methacrylonitrile, and α-chloroacrylonitrile, but especially
AN is preferred. Specific examples of vinyl monomers that can be copolymerized with aromatic vinyl monomers and vinyl cyanide monomers include various known vinyl monomers such as methacrylic esters, acrylic esters, methacrylic acid, and acrylic acid. One or more of the selected types. Rubber-like polymers with a glass transition temperature (Tg) of 0°C or less include polymers of conjugated diene compounds such as butadiene and isoprene alone or with copolymerizable vinyl monomers, and acrylic acid ester copolymers. In particular, polybutadiene or butadiene copolymers are preferred. The graft copolymer of component (b) is a mixture of 30 to 80 parts by weight of a rubbery polymer having a Tg of 0°C or less and 20 to 70 parts by weight of a monomer mixture such as aromatic vinyl and vinyl cyanide in the proportions described above. was graft-polymerized by a known method. Next, examples of aromatic vinyl monomers constituting the copolymer of component (c) include SM, αMSM, vinyltoluene, t-butylstyrene, halogen-substituted styrene, and mixtures thereof, particularly SM and mixtures thereof. is preferred. Examples of vinyl cyanide monomers include AN, methacrylonitrile, and α-chloroacrylonitrile, with AN being particularly preferred. Furthermore, vinyl monomers that can be copolymerized with aromatic vinyl monomers and vinyl cyanide monomers include methacrylic esters and acrylic esters. Here, a particularly preferable copolymer as component (c) is
These are SM/AM copolymer and SM/αMSM/AN copolymer. The copolymer of component (c) is produced by a known production method, such as a suspension polymerization method or a bulk polymerization method. In the present invention, the above-mentioned components (a), (b), and (c) may be mixed using a known conventional method, such as a single-screw or twin-screw extruder, an extruder equipped with a vent, a mixing roll, or a kneader. It can be mixed by etc. Known fillers, stabilizers, flame retardants, pigments, lubricants, plasticizers, antistatic agents, and/or glass fibers can be added to the resin composition produced as described above, if necessary. EXAMPLES The present invention will be specifically explained below with reference to Examples, but these are not intended to limit the scope of the present invention. Note that all parts and percentages described in this specification are expressed on a weight basis. Example 1 and Comparative Example 1 (a) Production of copolymer of component 210 parts of αMSM, 15 parts of SM,
45 parts AN, 37.5 parts 20% aqueous solution of sodium dodecylbenzenesulfonate (DBSN), potassium chloride
0.15 parts of t-dodecyl mercaptan, 1.5 parts of t-dodecyl mercaptan, and 640 parts of water were charged, the temperature was raised to 70°C, and then 20 parts of a 1% potassium persulfate aqueous solution was added to initiate polymerization. Further, 10 parts of the same aqueous solution was added 6 hours later. The polymerization rate 1 hour after the start of polymerization was 12.3
It was %. From this point on, use a metering pump.
30 parts of AN were added to the polymerization system at a rate of 5 parts per hour over 6 hours. In order to observe the polymerization rate and changes in the composition of unreacted monomers during the course of the polymerization, a small amount of the emulsion was sampled from the polymerization vessel. Polymerization was stopped in 10 hours. The polymerization rate at that time was 96.8%. The polymer emulsion sampled during the process was analyzed by gas chromatography. The result is the first
Shown in the table.

[Table] The polymer emulsion thus obtained was coagulated with calcium chloride to separate the polymer, which was dehydrated and dried to obtain a white powdery polymer. (b) Production of graft copolymer of component 286 parts of polybutadiene latex (polybutadiene solid concentration 35%, average particle diameter 350 mμ; gel content 87%), 400 parts water, potassium fatty acid 2
0.006 parts of ferrous sulfate, 0.015 parts of tetrasodium ethylenediaminetetraacetate, and 0.3 parts of sodium formaldehyde sulfoxylate were charged into a polymerization vessel, and while stirring at a temperature of 50°C, 0.8 parts of t-dodecylmercaptan and 0.3 parts of dicumyl peroxide were added. 105 parts of SM dissolved in
150 parts of a monomer mixture containing 45 parts of AN were added in portions over 3 hours. After the completion of the fractional addition, the temperature was heated to 65°C and polymerization was continued for an additional hour. The polymer emulsion thus obtained was coagulated with calcium chloride to separate the polymer, which was then dehydrated and dried to obtain a white powdery polymer. The powders of components (a) and (b) obtained as above were mixed so that the polybutadiene content in the resin composition was 16%, extruded using a vented extruder, pelletized, and then injected. It was molded and its physical properties were measured. The results are shown in Table 3. In addition, as Comparative Example 1 for comparison, in the production of the copolymer of component (a), 210 parts of αMSM, 15 parts of SM, and 60 parts of AN were charged in a polymerization vessel.
The same procedure as in Example 1 was conducted except that AN was added to the polymerization system over 1 hour at a rate of 15 parts per hour starting 7 hours after the start of polymerization. The results of the polymerization rate and unreacted monomer molar ratio in the polymerization of component (a) are shown in Table 4, and the physical properties of the composition obtained by mixing components (a) and (b) are shown in Table 3. .

[Table] Example 2 (a) Production of copolymer of component 222 parts of αMSM and 40 parts of AN were placed in a polymerization vessel, and immediately after the start of polymerization, AN was polymerized at a rate of about 5.43 parts per hour for a total of 38 parts over 7 hours. The same procedure as in Example 1 was carried out except that it was added to the system. The polymerization rate and the molar ratio of unreacted monomer of αMSM to AN were as follows.

[Table] The thus obtained copolymer was blended with the same graft copolymer (b) as in Example 1 so that the polybutadiene content in the resin composition was 16%, and its physical properties were measured. did. Example 3 Production of graft copolymer of component (b) Polybutadiene latex similar to Example 1
286 parts, 187 parts of water, 1 part of potassium fatty acid, 0.004 part of ferrous sulfate, 0.01 part of tetrasodium ethylenediaminetetraacetate, and 0.2 part of sodium formaldehyde sulfoxylate were charged into a polymerization container.
0.36 parts of t-dodecyl mercaptan and 0.12 parts of dicumyl peroxide while stirring at a temperature of 50°C.
The same procedure as in Example 1 was carried out, except that 60 parts of a monomer mixture of 42 parts of SM and 18 parts of AN were added over a period of 3 hours. The thus obtained graft copolymer was blended with the same component (a) copolymer as in Example 2 so that the polybutadiene content in the resin composition was 18.75%, and its physical properties were measured. Example 4 35 parts of a copolymer similar to component (a) of Example 2, 30 parts of a graft copolymer similar to component (b) of Example 3, and
Component (c) is a styrene-acrylonitrile copolymer produced by suspension polymerization (trade name: "Denka AS-S").
(Denki Kagaku Kogyo) was mixed and its physical properties were measured. Example 5 The same procedure as in Example 1 was carried out, except that the monomer mixture for producing the graft copolymer of component (b) was 100 parts of SM, 35 parts of AN, and 15 parts of methyl methacrylate, and the physical properties were measured. Example 6 When producing the copolymer of component (a) in Example 1, SM15
The physical properties were measured in the same manner as in Example 1 except that 15 parts of methacrylic acid was used instead of 15 parts of methacrylic acid. Example 7 When producing the copolymer of component (a) in Example 1, SM15
The physical properties were measured in the same manner as in Example 1 except that 15 parts of N-phenylmaleimide was used instead of 15 parts of N-phenylmaleimide. Example 8 When producing the copolymer of component (a) in Example 1, 190 parts of αMSM was added instead of 210 parts of αMSM and 15 parts of SM.
Example 1 except that 35 parts of methyl methacrylate was used.
The physical properties were measured in the same manner as above. Example 9 In producing the graft copolymer of component (b) in Example 1, poly(styrene-butadiene) copolymer latex (solid content 43%, butadiene content 72%, average particle size) was used instead of polybutadiene latex. Diameter 300
The physical properties were measured in the same manner as in Example 1 except that 233 parts (mμ; gel content 85%) were used.

[Table] The physical properties shown in Table 3 were determined by the following method. (1) Heat distortion temperature is ASTM method D648-56 (18.6Kg/
^cm2 ). (2) Vikatsu softening point was based on ASTM method D1525 (5 kg load). (3) Izot impact strength is ASTM method D256-56
(1/4 inch, 20℃ value). (4) Falling weight impact strength is injection molded with a thickness of 2 mm, length and width.
A 1 kg iron weight with a 1 cm diameter ball at the tip was dropped onto a 12 x 12 cm plate and the maximum height without breaking was measured. (5) Fluidity MFI is ASTM method D1238 (250℃, 5Kg
load). Molded product coloring test at temperature 260
Tensile test specimens injection molded at °C were visually observed.

Claims (1)

[Scope of Claims] 1. A thermoplastic resin composition containing each of the following components (a), (b), and (c) as main components. (a) Components are aqueous emulsion polymerization of 65 to 80% by weight of aromatic vinyl monomers, 15 to 30% by weight of vinyl cyanide monomers, and 0 to 20% by weight of vinyl monomers copolymerizable with these. It is a copolymer, and the aromatic vinyl monomer is present in its entirety at the start of polymerization, and the vinyl cyanide monomer is partially present at the start of polymerization to initiate polymerization, and the polymerization is completed from the start of polymerization to the end of polymerization. During this period, the remaining vinyl cyanide monomer is added to the polymerization system at a rate substantially slower than the polymerization rate of the aromatic vinyl monomer, and at a polymerization rate of between 0 and 90%, The composition ratio of the unreacted monomers is such that the total number of moles of the aromatic vinyl monomer and the copolymerizable vinyl monomer is 1.3 to 3 times the number of moles of the vinyl cyanide monomer. 20 to 85 parts by weight of copolymer retained to substantially complete polymerization. (b) Components include 30 to 80 polymerized parts of a rubbery polymer with a glass transition temperature of 0°C or lower, 50 to 80% by weight of aromatic vinyl monomer, 15 to 35% by weight of vinyl cyanide monomer, and copolymerized with these. 10-50 parts by weight of a copolymer grafted with 20-70 parts by weight of a monomer mixture consisting of 0-30% by weight of possible vinyl monomers. (c) A monomer mixture consisting of 50 to 80% by weight of an aromatic vinyl monomer, 15 to 35% by weight of a vinyl cyanide monomer, and 0 to 30% by weight of a vinyl monomer copolymerizable with these. 0 to 50 parts by weight of a copolymerized polymer. 2. Claim 1, wherein the aromatic vinyl monomer of component (a) is mainly composed of α-methylstyrene, and the vinyl cyanide monomer is acrylonitrile and/or methacrylonitrile. The thermoplastic resin composition described. 3. The copolymerizable vinyl monomer of component (a) is one or more selected from acenaphthylene, fumaronitrile, maleimide, N-substituted maleimide, methacrylic acid, acrylic acid, methacrylic ester, and acrylic ester. A thermoplastic resin composition according to claim 1 characterized by: 4. Claims 1 or 2, characterized in that the aromatic vinyl monomer of component (b) is mainly composed of styrene, and the vinyl cyanide monomer is acrylonitrile and/or methacrylonitrile. The thermoplastic resin composition described in . 5. The heat treatment according to claim 1, 2 or 4, wherein the copolymerizable vinyl monomer of component (b) is one or more selected from methacrylic esters and acrylic esters. Plastic resin composition. 6. The thermoplastic resin composition according to claim 1, 2 or 4, wherein the rubbery polymer as component (b) is a rubber containing 50% by weight or more of butadiene. 7. Claim 1, wherein the component (c) is a styrene-acrylonitrile copolymer,
Thermoplastic resin composition according to item 2 or 4.