JPH0354126B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention is made of an aromatic vinyl compound reinforced with a rubber-like polymer having a branched structure using a specific coupling agent, or an aromatic vinyl compound and at least one vinyl monomer copolymerizable with the aromatic vinyl compound. The present invention relates to a method for producing a resinous polymer composition. Rubbery polymer reinforced styrene polymer (hereinafter referred to as
HIPS resin) and styrene-acrylonitrile copolymer (ABS resin) have excellent impact resistance and are used in many fields as plastics with a good balance of mechanical properties and processability. . Among these rubber reinforced resins, ABS
Regarding resins, compared to the general emulsion polymerization method, the polymer recovery and finishing processes are simpler from a manufacturing perspective, and the amount of chemicals used in the polymerization and finishing processes can be reduced.
Bulk polymerization, solution polymerization, bulk suspension polymerization, etc. have been actively studied and adopted. However, ABS manufactured by these methods
Resins are still inferior to those produced by emulsion polymerization in terms of the appearance of molded products, particularly in terms of surface gloss. On the other hand, the mainstream method for producing HIPS resins is the bulk-suspension polymerization method, but the appearance of molded products, especially the surface gloss, is insufficient, so the fields of use are currently limited. There are many factors that determine the physical properties of ABS resins or HIPS resins, and they are intricately related to each other, but among them, the dispersion state of the rubber, that is, the particle size and the degree of crosslinking, are important factors. In emulsion polymerization, if a rubber latex with a certain particle size and degree of crosslinking is used, it is possible to obtain
While the desired dispersed rubber particle size and degree of crosslinking can be obtained with ABS resin and HIPS resin,
This problem must be overcome using polymerization techniques in bulk polymerization, etc., and it is difficult to obtain an ideal rubber dispersion state and structure, which is considered to be a factor in the poor gloss. Gel-free polybutadiene and random SBR are generally used as reinforcing rubbery polymers used in bulk polymerization and the like. The use of block polymers as new rubbery polymers has also been proposed. However, in both cases, special polymerization conditions and a reactor are required to obtain resins with excellent surface gloss, and there are many practical problems. The inventors of the present invention have conducted intensive studies on the above-mentioned problems, and have found that they can be solved by using a specific rubbery polymer, and have arrived at the present invention. That is, the method of the present invention adds an aromatic vinyl compound or an aromatic vinyl compound to a conjugated diene polymer rubber or a conjugated diene aromatic vinyl compound copolymer rubber having a branched structure produced using a specific coupling agent. It is characterized by graft polymerization of at least one type of copolymerizable vinyl monomer. When the rubbery polymer of the present invention is used, ABS resin or
HIPS resins can be easily produced in conventional reactors under conventional polymerization conditions. Next, the method of the present invention will be specifically explained. The rubbery polymer used in the present invention can react with a living polymer obtained by polymerizing a conjugated diene or a conjugated diene and an aromatic vinyl compound using an organolithium-based catalyst and the active lithium end of the polymer. A rubbery polymer having a branched structure obtained by a coupling reaction with a tin halide compound having at least two or more reactive sites, the ratio of the branched polymer to the total polymer (coupling efficiency) being 20 to 80. Conjugated diene polymer rubber with a vinyl bond content of 30 to 90% in the conjugated diene moiety, or a conjugated diene polymer rubber consisting of a conjugated diene and an aromatic vinyl compound with an aromatic vinyl compound content of 40% by weight or less It is a random copolymer rubber. In the present invention, the organolithium catalyst is n-
Propyllithium, Isopropyllithium, n-
Monolithium compounds such as butyllithium and t-butyllithium are preferably used. Further, as the tin halide compound as a coupling agent, methyltrichlorotin, tetrachlorotin, butyltrichlorotin, octyltrichlorotin, methyltribromtin, octyltribromtin, tetrabromtin, etc. are used. The bonding mode of the branched structure portion coupled using a tin halide compound is not particularly limited, but by forming a tin-butadienyl bond, the degree of discoloration of the obtained resin during high-temperature molding can be reduced. This copolymer of a conjugated diene having a tin-butadienyl bond and an aromatic vinyl compound is prepared by adding a small amount of a conjugated diene before adding a coupling agent.
It is then obtained by adding a coupling agent and coupling. When forming a branched structure using a coupling agent in the present invention, the effects of the present invention can be achieved by controlling the proportion of the branched polymer to the total polymer (coupling efficiency) to be 20 to 80% by weight, preferably 30 to 70% by weight. This is an essential condition. If the coupling efficiency is less than 20% by weight or more than 80% by weight, the surface gloss will decrease. Conjugated dienes in the present invention include 1,3-butadiene and isoprene, and aromatic vinyl compounds include styrene, P-methylstyrene, vinyltoluene, α-methylstyrene, 3,5-dimethylstyrene, etc. Preferred is 1,3-butadiene or a combination of 1,3-butadiene and styrene. In the rubbery copolymer of a conjugated diene and an aromatic vinyl compound, the content of the aromatic vinyl compound is 40% by weight or less, preferably 30% by weight or less. If it exceeds 40% by weight, impact resistance will decrease. By copolymerizing an aromatic vinyl compound as a component of the rubbery polymer, a resin with better gloss than a polybutadiene rubber-modified thermoplastic resin can be obtained. Therefore, at least 5% by weight of the aromatic vinyl compound in the copolymer rubber is It is preferable to use those containing The vinyl bond content of the conjugated diene portion of the conjugated diene polymer rubber or conjugated diene-aromatic vinyl copolymer rubber used in the present invention is 30 to 90%, preferably 35 to 90%. Vinyl bond content is 30
If it is less than 90%, the degree of discoloration during high-temperature molding will be large, while if it exceeds 90%, the impact resistance will be greatly reduced. Here, the vinyl bond represents a 1,2 bond when butadiene is used as the conjugated diene,
Also, when isoprene is used, 1, 2 bonds and 3,
Represents a 4-bond. The vinyl bond content of the conjugated diene moiety can be appropriately adjusted by adding a microstructure modifier such as ether or tertiary amine and/or changing the polymerization temperature. In order to form a resinous polymer, the monomers subjected to graft polymerization in the presence of the rubbery polymer described above are an aromatic vinyl compound or an aromatic vinyl compound and at least one vinyl monomer copolymerizable therewith. It is a mixture consisting of several molecules. As the aromatic vinyl compound, styrene, P-methylstyrene, vinyltoluene, α-methylstyrene, etc. are used.
Vinyl monomers that can be copolymerized with aromatic vinyl compounds include vinyl cyanide compounds such as acrylonitrile and methacrylonitrile, and (meth) vinyl monomers such as methyl methacrylate and ethyl acrylate.
Examples include acrylic esters and acrylamide derivatives, and these may be used alone or in combination of two or more. By selecting a specific monomer from these vinyl monomers and using it in combination with an aromatic vinyl compound, a rubber-modified thermoplastic resin composition with excellent transparency can be obtained. In particular, the composition of the invention
It has excellent surface gloss, so there is little diffused reflection of light on the surface and good transparency. The ratio of the aromatic vinyl compound and the vinyl monomer copolymerizable with it is 100:0 to 100:0 by weight.
A ratio of 60:40 is appropriate. The graft polymer can be produced by bulk polymerization, solution polymerization, suspension polymerization, or a combination thereof.
Batchwise or continuously, for example, JP-A-56-
50906 can be carried out by the continuous construction process disclosed in US Pat. The effects of the present invention can also be achieved in the so-called graft blending method, in which a resinous polymer made of at least one monomer selected from the above monomers is separately produced and blended with the graft polymer thus obtained. It is possible to grant The ratio of the rubbery polymer to the resinous polymer in the rubber-modified thermoplastic resin composition of the present invention is such that the rubbery polymer accounts for 2 to 40% by weight of the total resin composition. If the amount of the rubbery polymer is less than 2% by weight, the impact resistance will decrease, making it impossible to achieve the object of the present invention, and if the amount exceeds 40% by weight, the rigidity will decrease, which is not preferable. EXAMPLES The present invention will be explained in more detail with reference to Examples below. The rubbery polymer used in the present invention is produced by the following method. 1,3- as a monomer in cyclohexane 5
Butadiene or styrene and 1,3-butadiene were charged, and polymerization was carried out using tetrahydrofuran as a randomizing agent and vinyl bond regulator, and n-butyllithium as a polymerization initiator.
After the polymerization was completed, a coupling agent was added.
Before adding the coupling agent, add a small amount of 1,3-
Butadiene may also be added. The polymer is added to the polymerization solution by adding 1.0 parts by weight of 2 to 100 parts by weight of the polymer.
After adding 6-dithyabutyl-P-cresol, the solvent was removed by steam stripping, dried with a roll at 100°C, and collected. The properties of the obtained polymer are shown in Table 1.

[Table] Examples 1 to 8, Comparative Examples 1 to 5 As shown in Table 2, a solvent and a monomer mixture were charged into a stainless steel reactor equipped with a stirring device, and then a rubbery polymer was added and dissolved. Dicumyl peroxide was added as a polymerization initiator and t-dodecyl mercaptan was added as a molecular weight regulator to this solution, and polymerization was carried out while maintaining the temperature at 110 to 120°C. Polymerization was stopped when the conversion rate reached 60%, and the residual monomer was then removed under reduced pressure and granulated using an extruder. Test pieces were molded using an injection molding machine (220°C) and their physical properties were measured.

【table】

[Table] As is clear from the results of Examples 1 to 8 in Table 2, an aromatic vinyl compound or an aromatic vinyl compound and a vinyl monomer copolymerizable therewith are graft-polymerized to the rubbery polymer of the present invention. It can be seen that a resin with excellent impact resistance and molded appearance, especially gloss, can be obtained. In particular, in Example 4, a resin with excellent transparency is obtained by graft polymerizing a monomer mixture of styrene-methyl methacrylate. On the other hand, as shown in Comparative Examples 1 and 2, when a rubbery polymer in which the proportion of the branched polymer to the total polymer is outside the range of the present invention is used, the gloss is significantly reduced. Furthermore, as shown in Comparative Example 3, when the vinyl bond content is outside the range of the present invention, the degree of discoloration during high temperature molding becomes significantly large, and as shown in Comparative Example 4, the aromatic vinyl compound in the rubbery polymer When the content is outside the range of the present invention, the impact resistance is greatly reduced, and as shown in Comparative Example 5, those using coupling agents other than the tin compound of the present invention have poor gloss and color tone.

Claims (1)

[Scope of Claims] 1. Consisting of (A) 2 to 40 parts by weight of a rubbery polymer, and (B) an aromatic vinyl compound or an aromatic vinyl compound and at least one vinyl monomer copolymerizable with the aromatic vinyl compound. Consisting of 98 to 60 parts by weight of resinous polymer,
A method for producing a rubber-modified thermoplastic resin composition obtained by polymerizing some or all of the monomers in (B) in the presence of (A), wherein (A) is a conjugated diene or a conjugated diene and an aromatic A rubber-like polymer having a branched structure obtained by a coupling reaction between a living polymer obtained by polymerizing a group vinyl compound using an organolithium-based catalyst and a tin halide compound, the rubber-like polymer having a branched structure, comprising: (a) bonding of the branched portion; The proportion of branched butadiene-based polymers in which is a tin-subbutadienyl bond is 20 to 80.
Weight% (b) Vinyl bond content of conjugated diene part is 35-90
% (c) A method for producing a rubber-modified thermoplastic resin composition, which comprises using component (A) in which the weight ratio of the conjugated diene component to the aromatic vinyl compound component is 100:0 to 60:40.