JPH05247149A - Rubber-modified aromatic vinyl coopolymer resin and its production - Google Patents

Abstract

PURPOSE:To obtain the subject resin having excellent gloss, impact resistance and fluidity by dispersing a rubber component in a specific matrix resin in the form of particles. CONSTITUTION:The objective resin can be produced by polymerizing (A) 100 pts.wt. of a matrix resin (having a weight-average molecular weight of 70,000-165,000) composed of a copolymer of (i) 60-99wt.% of an aromatic vinyl monomer and (ii) 1-40wt.% of a vinyl cyanide monomer or a copolymer of the components (i) and (ii) and (iii) a vinyl monomer copolymerizable with the above components, (B) 3-20 pts.wt. of a rubber component (having a 5% styrene solution viscosity of 10-50cps at 25 deg.C and an average particle diameter of 0.2-2mum) containing a styrene-butadiene rubber of the formula XmY [X is block copolymer (having a styrene content of <=15%) consisting of a copolymer block composed mainly of butadiene and a copolymer block composed mainly of styrene; Y is residue of polyfunctional coupling agent used for forming a radial polymer and bonded to the terminal butadiene residue of the butadiene copolymer block of X; (m) is number of functional groups of a polyfunctional coupling agent and is >=3] and (C) 2-100 pts.wt. of a solvent. The styrene-butadiene rubber of the component B accounts for >=50% of the total rubber component.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a rubber-modified aromatic vinyl copolymer resin and a method for producing the same.

[0002]

ABS resin is a rubber-modified aromatic copolymer resin in which a rubber component is dispersed in particles in a matrix resin composed of a copolymer of an aromatic vinyl monomer and a vinyl cyanide monomer. Well-known, home appliances / OA equipment / A
It is used in housings for V-equipment and instrument panels of automobiles. With the diversification of applications, the appearance of molded products has been emphasized, and further improvement in mechanical strength and moldability has been strongly demanded. However, a method of reducing the molecular weight of the matrix resin can be considered as a method of improving the gloss characteristics and fluidity of the resin, but on the contrary, there is a problem that the impact resistance is lowered. Further, as a method of improving the impact resistance, a method of increasing the content of the rubber component or increasing the particle diameter of the rubber dispersed particles can be considered, but on the contrary, there is a problem that the gloss decreases. Thus, AB
There is a great demand for simultaneously improving the gloss characteristics, impact resistance and fluidity of the S resin, but it is very difficult to realize. On the other hand, Japanese Patent Application Laid-Open No. 63-207803 discloses a resin that solves such a problem by using a linear block styrene butadiene rubber having a styrene content of 10 to 30% by weight as a rubber component. ing. On the other hand, when the present inventor conducted a test, the general formula X _m
Y [however, X is a block copolymer comprising a copolymer block mainly containing butadiene and a copolymer block mainly containing styrene, and the styrene content of the block copolymer is 15% by weight or less. The polymer block, Y, represents the residue of the polyfunctional coupling agent used to form the radial polymer, and Y is bonded to the butadiene residue at the end of the butadiene-based copolymer block of X. m represents the number of functional groups of the polyfunctional coupling agent, and is an integer of at least 3 or more. ] It has been found that the styrene-butadiene rubber having a branched structure represented by the above formula is superior in the above physical properties to the case where a linear block styrene-butadiene rubber is used.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a rubber-modified aromatic vinyl copolymer resin having good gloss properties, impact resistance and fluidity as a whole. Moreover, it is providing the manufacturing method.

[0004]

Means for Solving the Problems The present inventor has conducted research to solve the above problems, and as a rubber component, a compound of the general formula X _m Y [where X is a copolymer block mainly containing butadiene] A block copolymer composed of a copolymer block mainly composed of styrene, wherein the styrene content of the block copolymer is 15% by weight or less, Y is a polymer block used for forming a radial polymer. It represents the residue of the functional coupling agent, and Y is bonded to the butadiene residue at the end of the copolymerized block of X mainly containing butadiene. m represents the number of functional groups of the polyfunctional coupling agent, and is an integer of at least 3 or more. ] And has a branched structure represented by 25
It was found that it is effective to use a styrene-butadiene rubber having a 5 wt% styrene solution viscosity at 10 ° C. of 10 to 50 cps, and to specify the average molecular weight of the matrix resin and the average particle size of the rubber dispersed particles. Was completed.

That is, the present invention relates to a copolymer of an aromatic vinyl monomer and a vinyl cyanide monomer, or an aromatic vinyl monomer and a vinyl cyanide monomer and a vinyl monomer which can be copolymerized therewith. Matrix resin 1 consisting of copolymer with monomer
A rubber-modified aromatic vinyl-based copolymer resin in which 3 to 20 parts by weight of a rubber component is dispersed in a particle shape based on 00 parts by weight, and the aromatic vinyl monomer content of the matrix resin is 60 to 99. % By weight, vinyl cyanide monomer content is 1
-40% by weight, weight average molecular weight 70,000-1650
00, and 50% by weight or more of the total rubber component is represented by the general formula X
_m Y [where X is a block copolymer composed of a copolymer block containing butadiene as a main component and a copolymer block containing styrene as a main component, and the styrene content of the block copolymer is 15% by weight or less. One polymer block, Y represents the residue of the polyfunctional coupling agent used to form the radial polymer, and Y is bonded to the terminal butadiene residue of the butadiene-based copolymer block of X. .. m represents the number of functional groups of the polyfunctional coupling agent, and is an integer of at least 3 or more. ] A styrene-butadiene rubber having a branched structure represented by the following formula, a 5 wt% styrene solution viscosity of the rubber component is 10 to 50 cps, and an average particle diameter (Dw) of dispersed particles of the rubber component is 0.2 to 2 μm. Is a rubber-modified aromatic vinyl-based copolymer resin. Also,
100 parts by weight of a monomer mixture having an aromatic vinyl monomer content of 60 to 99% by weight and a vinyl cyanide monomer content of 1 to 40% by weight, a general formula X _m Y (where X is butadiene Is a block copolymer consisting of a copolymer block mainly containing styrene and a copolymer block mainly containing styrene, wherein the styrene content of the block copolymer is 15% by weight or less, and Y is a radial block. It represents a residue of a polyfunctional coupling agent used for polymer formation, and Y is bonded to the butadiene residue at the end of the butadiene-based copolymerization block of X. m represents the number of functional groups of the polyfunctional coupling agent, and is an integer of at least 3 or more. ] 5 wt% styrene solution viscosity is 10 to 50 cps. A polymerization initiator is added to a raw material liquid consisting of 3 to 20 parts by weight of a rubber component mainly composed of a styrene-butadiene rubber having a branched structure and 2 to 100 parts by weight of a solvent. The rubber-modified aromatic vinyl-based copolymer according to claim 1, further comprising: adding a chain transfer agent to polymerize the monomer mixture until a polymerization addition ratio of the monomer mixture reaches 40 to 95%, and then removing a volatile component. It is a method for producing a polymer resin.

First, the rubber-modified aromatic vinyl copolymer resin of the present invention will be described. The matrix resin is a copolymer of an aromatic vinyl monomer and a vinyl cyanide monomer or a copolymer of an aromatic vinyl monomer, a vinyl cyanide monomer and a vinyl monomer copolymerizable therewith. It is a polymer. However, the content of aromatic vinyl monomer is 60 to 99% by weight, and the content of vinyl cyanide monomer is 1 to 40%.
The content of other vinyl monomers is 39% by weight.
It is less than or equal to weight%. If the content of vinyl cyanide monomer is less than 1% by weight, the chemical resistance, rigidity and heat resistance are poor, and if it exceeds 40% by weight, the fluidity is poor.

As aromatic vinyl monomers, side chain alkyl-substituted styrenes such as styrene and α-methylstyrene, nuclear alkyl-substituted styrenes such as vinyltoluene, halogenated styrenes such as chlorostyrene, and divinylbenzene are used. Examples of the vinyl cyanide monomer include acrylonitrile, methacrylonitrile, fumaronitrile, maleonitrile, and α-chloroacrylonitrile.Other vinyl monomers that can be copolymerized with these include: Examples thereof include acrylic acid esters such as methyl methacrylate, maleic anhydride, phenylmaleimide, ethylene, propylene, butadiene and vinyl chloride.

The weight average molecular weight of the matrix resin is 70,000 to 165,000, preferably 95,000.
140000. If the weight average molecular weight of the matrix resin is less than 70,000, the impact resistance is poor, and 1650
If it exceeds 00, the fluidity is poor. The weight average molecular weight of the matrix resin in the present invention is a polystyrene-equivalent average molecular weight determined by gel permeation chromatography (GPC method).

More than 50% by weight of the rubber component has the general formula X _m
Y [however, X is a block copolymer comprising a copolymer block mainly containing butadiene and a copolymer block mainly containing styrene, and the styrene content of the block copolymer is 15% by weight or less. The polymer block, Y, represents the residue of the polyfunctional coupling agent used to form the radial polymer, and Y is bonded to the butadiene residue at the end of the butadiene-based copolymer block of X. m represents the number of functional groups of the polyfunctional coupling agent, and is an integer of at least 3 or more. ] It is a styrene butadiene rubber represented by the following, and has a branched structure by a tri- to hexavalent polyfunctional coupling agent. In the case of a butadiene-styrene block copolymer rubber having a branched structure in which Y is a styrene residue at the end of a copolymer block mainly composed of styrene of X, steric hindrance of the phenyl group of styrene to be bonded to Y. Is large and m is large, the yield of the synthesis reaction is remarkably reduced, and the coupling agent is also limited, so that there are many economical problems, which is not preferable. Up to 50% by weight of the rubber component in the present invention may be mixed with a linear polybutadiene rubber or a linear styrene butadiene rubber having no branched structure. If the mixing ratio of the linear polybutadiene rubber or the linear styrene butadiene rubber in the rubber component exceeds 50% by weight, the impact resistance is poor and the cold flow becomes large and the handling becomes difficult. 5% by weight of rubber component at 25 ° C
Styrene solution viscosity is 10-50 cps, preferably 20-
It is 40 cps. A rubber component having a 5 wt% styrene solution viscosity at 25 ° C of less than 10 cps has poor impact resistance, and a rubber component having a viscosity of more than 50 cps has poor gloss properties. By using the branched rubber component in the present invention, the impact resistance is remarkably improved as compared with the linear polybutadiene rubber or the linear block styrene butadiene rubber. It is considered that this is because the branched rubber has a larger molecular weight than the linear polybutadiene rubber, so that the rubber-like properties are less likely to be impaired.

The rubber component is dispersed in the matrix resin in the form of particles, and the average particle diameter (Dw) of the rubber dispersed particles is 0.
2 to 2 μm, preferably 0.3 to 1 μm. If the average particle size of the rubber dispersed particles is less than 0.2 μm, the impact resistance is poor, and if it exceeds 2 μm, the gloss property is poor. The rubber-dispersed particles containing the copolymer resin component have a good balance of gloss characteristics and impact resistance, and the graft ratio of the copolymer resin component to the rubber-dispersed particles is 0.4 to 1, Further, those having a swelling ratio of 6 to 11 are particularly excellent.

Next, a method for producing the rubber-modified aromatic vinyl-based copolymer of the present invention by solution polymerization will be described. A monomer mixture containing an aromatic vinyl monomer and a vinyl cyanide monomer, with a polymerization initiator and a chain transfer agent,
Graft copolymerization is performed in the presence of a rubber component and a solvent. Solvents that can be used are benzene, toluene, xylene,
In addition to aromatic hydrocarbon compounds such as ethylbenzene, ketone compounds such as acetone, methyl ethyl ketone and acetophenone, and alcohol compounds such as propyl alcohol and phenol can be used, but the aromatic hydrocarbon compounds are used alone. Alternatively, an aromatic hydrocarbon compound and a ketone compound or an alcohol compound can be used in combination. The amount of the solvent used is 2 to 100 parts by weight based on 100 parts by weight of the monomer mixture. When the amount of the solvent used is small, the viscosity of the reaction liquid becomes high, so that it becomes difficult to control the formation of the rubber dispersed particles, and when the amount is too large, the efficiency of the polymerization reaction deteriorates.

A radical polymerization initiator such as an organic peroxide is preferably used as the polymerization initiator, and the amount thereof is not particularly limited, but 0.005 to 100 parts by weight of the monomer mixture is used. 0.5 parts by weight is preferred. In addition, chain transfer agents include mercaptans and α-methylstyrene dimer. Then, the polymerization reaction is performed in a complete mixing tank or a plug flow.
It is advisable to carry out the polymerization at a polymerization temperature of 80 to 160 ° C. with appropriate stirring in a polymerization reactor of a type reactor or a combination thereof.

In the present invention, the molecular weight of the matrix resin can be controlled by changing the type and amount of chain transfer agent and the position of addition. Further, the particle size of the rubber dispersed particles can be controlled by changing the stirring conditions in addition to the type and amount of the chain transfer agent used. That is, when the amount of the chain transfer agent used is increased, the average molecular weight of the matrix resin decreases, and when the stirring power is increased, the average particle size of the rubber dispersed particles tends to decrease.

The rubber-modified aromatic vinyl copolymer resin of the present invention is added with an ordinary antioxidant to improve the thermal stability, and a lubricant is added to further improve the fluidity. It can be made flame-retardant by adding a flame retardant. Further, a fiber reinforcing material, an inorganic filler, a coloring material, a pigment and the like can be blended according to the purpose. Further, it can be blended with other resins and used for molding.

[0015]

The present invention will be described in detail below. IZ; Izod impact strength measured according to ASTM-D-256 MI; Melt flow rate (220 ° C, 10 kg) measured according to JIS-K-7210 Gloss value; Value measured according to JIS-K-7105 .. The average particle diameter of the rubber-dispersed particles is a value calculated by the following formula 1 by measuring 200 to 1000 rubber particle diameters from transmission electron micrographs of a resin by an ultrathin section method. However, Ni in the formula 1 is the number of rubber dispersed particles having a particle diameter of Di. [Equation 1] Average particle diameter (Dw) = Σ (Ni · Di ⁴ ) / Σ (Ni · Di ³ ) Graft ratio (g); Sample A (about 1 g is precisely weighed) is dispersed in 30 cc of acetone to obtain insoluble matter. Is separated by a centrifugal separation method and dried, and the weight (B) of the acetone-insoluble matter is precisely weighed to obtain the following equation 2. However, C represents the content of the rubber-like polymer in the sample A. [Formula 2] Graft ratio (g) = (B / A−C) / C Swelling ratio; Sample D (about 1 g is precisely weighed) is put into 30 cc of 1/1 mixed solvent of toluene / methyl ethyl ketone and stirred for 1 hour. After dissolution, the mixture was centrifuged to remove the supernatant, and the weight (E) of the remaining swollen material was precisely weighed.
Characteristic value determined by the following Equation 3 [Equation 3] Swelling ratio = E / D

Example: Styrene content 75% by weight, acrylonitrile content 2
50 parts by weight of ethylbenzene, 12 parts by weight of a rubber component, 0.085 to 0.1 parts by weight of an organic peroxide-based polymerization initiator, and t-dodecyl mercaptan (based on 100 parts by weight of a 5% by weight monomer mixture). (Chain transfer agent) 0.35 parts by weight of a raw material liquid is mixed in a continuous polymerization process in which a plug flow type reactor and a complete mixing tank are combined in series to obtain a polymerization conversion of a monomer mixture of about 60 to 80%. After continuously polymerizing the solution until it became, the volatile matter was removed by a devolatilizer to produce an ABS resin having a rubber component content of about 13 to 17% by weight. In addition,
The rubber component has a branched structure and a styrene content of 2.5 wt% and a 5 wt% styrene solution viscosity of 25 cps.
Block type styrene butadiene rubber (RB-1)
It was used. Table 1 shows the physical properties of the obtained ABS resin.

Comparative Example As a rubber component, a block type styrene-butadiene rubber (SB-1) having a styrene content of 23% by weight, a 5% by weight styrene solution viscosity of 13 cps and no branched structure, or a styrene content of 10 was used. 5% by weight of styrene solution viscosity is 25 cps and has no branched structure, block type styrene-butadiene rubber (SB-2) or styrene content is 10% by weight and 5% by weight of styrene solution viscosity is 25%.
An ABS resin was produced under the same conditions as in Example except that a random styrene-butadiene rubber (SB-3) having a cps and no branched structure was used. Table 1 shows the physical properties of the obtained ABS resin.

[0018]

[Table 1]

[0019]

The rubber-modified aromatic vinyl-based copolymer resin of the present invention has good gloss, impact resistance and fluidity. Further, according to the manufacturing method of the present invention, it is possible to easily manufacture a resin having good gloss characteristics, impact resistance, and fluidity.

Claims (2)

[Claims] 1. A copolymer of an aromatic vinyl monomer and a vinyl cyanide monomer, or an aromatic vinyl monomer, a vinyl cyanide monomer and a vinyl monomer copolymerizable therewith. A rubber-modified aromatic vinyl-based copolymer resin in which 3 to 20 parts by weight of a rubber component is dispersed in a particulate form with respect to 100 parts by weight of a matrix resin made of a copolymer, and the aromatic vinyl monomer of the matrix resin. Content of 60 to 99% by weight,
The vinyl cyanide monomer content is from 1 to 40% by weight, the weight average molecular weight is from 70,000 to 165,000, and 50% by weight or more of the total rubber component is represented by the general formula X _m Y (where X is mainly butadiene). A block copolymer comprising a copolymer block containing styrene and a copolymer block containing styrene as a main component, wherein the styrene content of the block copolymer is 15% by weight.
The following polymer blocks, Y represents the residue of the polyfunctional coupling agent used to form the radial polymer, Y is X
Is bonded to the terminal butadiene residue of the copolymer block mainly containing butadiene. m represents the number of functional groups of the polyfunctional coupling agent, and is an integer of at least 3 or more. ] A styrene-butadiene rubber having a branched structure represented by the following formula, wherein the viscosity of a 5% by weight styrene solution of all rubber components at 25 ° C. is 10 to 50 cps, and the average particle diameter (Dw) of dispersed particles of the rubber component is 0.2. A rubber-modified aromatic vinyl-based copolymer resin, characterized in that it is ˜2 μm. 2. The aromatic vinyl monomer content is 60 to 99.
The vinyl cyanide monomer content is 1 to 40% by weight.
100 parts by weight of the monomer mixture of the general formula X _m Y [where X is a block copolymer consisting of a copolymer block mainly containing butadiene and a copolymer block mainly containing styrene, The styrene content of the polymer is 1
5% by weight or less of a polymer block, Y represents a residue of a polyfunctional coupling agent used for forming a radial polymer, and Y represents a butadiene residue at the end of a copolymerization block mainly containing butadiene of X. Are bound to. m represents the number of functional groups of the polyfunctional coupling agent, and is an integer of at least 3 or more. ] A 5 wt% styrene solution at 25 [deg.] C. has a viscosity of 10 to 50 cps. A raw material liquid consisting of 3 to 20 parts by weight of a rubber component mainly composed of a styrene-butadiene rubber having a branched structure and 2 to 100 parts by weight of a solvent. The rubber modification according to claim 1, wherein a polymerization initiator and a chain transfer agent are added to the solution to carry out solution polymerization until the polymerization conversion rate of the monomer mixture reaches 40 to 95%, and then the volatile matter is removed. A method for producing an aromatic vinyl copolymer resin.