JPH0725974B2 - Styrene resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a styrene-based resin composition having an excellent overall quality balance of impact resistance, appearance characteristics, processing fluidity, heat resistance and rigidity.

[Prior Art] Conventionally, there are HIPS resin and ABS resin as resins having a unique taste and excellent surface gloss and impact resistance, and they are widely used in home electric appliances, audio equipment and the like.

Recently, products for these applications have been made thinner, and as a result, it has been desired to further improve the surface gloss and impact strength of conventional rubber-modified styrene resins.

In order to improve such problems, for example, various microstructure factors such as dispersed particle size, particle size distribution, occlusion particle size distribution, and swelling index are selected to achieve a comprehensive improvement in quality. JP-A-60-130613 and JP-A-60-130614
(Japanese Patent Laid-Open Publication No. JP-A-2003-264), using finely specified dispersed particle size distribution (JP-A-55-120616 and JP-A-60-156709), and the like, but these have low rigidity,
The gloss and other physical properties are not always satisfactory.

The styrene-based resin, styrene-butadiene block copolymer and graft rubber particles are mainly used, and the styrene-butadiene block copolymer particles mainly include large particles in which a plurality of graft rubber particles and a matrix resin (styrene-based resin) are incorporated. Although a formed material is also proposed (Japanese Patent Publication No. 61-21971), it is recognized that such a structure has excellent impact resistance, heat resistance, etc., but sufficient process fluidity. There is a drawback that it is not.

[Problems to be Solved by the Invention] The present invention has particularly good impact resistance and surface gloss, has a comprehensive balance of qualities such as process fluidity, heat resistance, and rigidity, and has excellent overall physical properties. It is an object of the present invention to provide a styrene resin composition having

[Means for Solving Problems] The present inventors have noticed that the particle size distribution of the dispersoid dispersed in the polystyrene matrix has a great influence on the mechanical properties of the polystyrene resin composition, and With a specific diameter distribution, it has excellent impact resistance and appearance characteristics, as well as excellent processing fluidity, heat resistance, rigidity, etc.
The present invention has been completed by finding that a styrene resin composition having a good overall quality balance can be obtained.

That is, the present invention relates to [A] rubber-modified styrene resin 98
Styrene comprising 80 to 80% by weight and 2 to 20% by weight of at least one rubber particle selected from (B) (a) styrene-butadiene block copolymer rubber and (b) methylmethacrylate-styrene-butadiene graft rubber. 75% by weight or more of a resin resin composition, the dispersed particles comprising a rubber component in the resin composition having a particle size of less than 0.4μ,
Particles with a particle size of 0.4μ to 2.1μ are 5 to 25% by weight.
What exceeds 2.1μ provides a styrene resin composition having a particle size distribution of 10% by weight or less.

The rubber-modified styrenic resin used as the component A in the composition of the present invention is a rubber-like polymer such as polybutadiene, polyisoprene, styrene-butadiene random copolymer, styrene, vinyltoluene, p-methylstyrene, tert-
One or more styrene-based monomers such as butyl styrene, p-chlorostyrene, α-methylstyrene, or the above-mentioned styrene-based monomers and methyl methacrylate copolymerizable therewith, acrylonitrile, maleic anhydride, etc., respectively. A styrene-based resin containing a graft polymer obtained by graft-polymerizing a mixture of one or more kinds, and representative ones include HI-PS, MI-PS, and styrene-butadiene-methyl methacrylate copolymer. There are coalescing, ABS, etc.

The rubber-modified styrene-based resin used as the component A in the composition of the present invention can be produced, for example, by dissolving the rubber in a styrene-based monomer liquid and then polymerizing the styrene-based monomer.

By this polymerization reaction, the rubber-modified styrene-based resin of the present invention is obtained as a composition containing the graft copolymer in the styrene-based resin. In the present invention, as a raw material for the production of this rubber-modified styrene resin, a rubber component is
The product manufactured by using 20% by weight can be used.

The styrene-butadiene block copolymer used as one of the component B in the composition of the present invention has a styrene content of 15 to 85 obtained by anionic polymerization of styrene and butadiene.
%, Preferably 25 to 75% by weight, and a block copolymer having a structure of (SB) n, (SB-)-nS, (BS-) ) -NB,
(S-B-)-mX (where S is a styrene block, B is a butadiene block, n is an integer of 1 to 5, m is an integer of 2 to 7, and X is a polymer of m units). Is a polyfunctional compound bound to each other, and these block copolymers may have a tapered portion whose composition ratio gradually changes).

The methylmethacrylate-styrene-butadiene graft rubber particles used as one of the component B in the composition of the present invention are produced, for example, by graft-polymerizing methyl methacrylate on a styrene-butadiene rubber latex obtained by an emulsion polymerization method. be able to. The size of the graft rubber particles is 0.05 to 1 µ in terms of weight average particle diameter,
Preferably, 0.1 to 0.5 μ can be used. If the weight average particle diameter is less than 0.05 μ, the impact resistance is lowered, and if it exceeds 1 μ, the appearance gloss of the resin molded product is significantly impaired.

The composition ratio of the component A and the component B used in the composition of the present invention is
The rubber-modified styrene resin as the component A is 80 to 98% by weight, preferably 85 to 96% by weight, and the component (a) styrene butadiene block copolymer or the component (b) methyl methacrylate-styrene-butadiene graft rubber is used. The particles are used individually or in combination of 2 to 20% by weight, preferably 4
~ 15% by weight can be used.

If the content of the component B in the composition of the present invention is less than 2% by weight, the impact resistance is lowered, and if it exceeds 20% by weight, the appearance is deteriorated.

To produce the styrenic resin of the present invention, a rubber for modifying the styrenic monomer and the (B) component (a) styrene-butadiene block copolymer or (b) methylmethacrylate-styrene-butadiene graft rubber particles are used. It can be produced by dissolving the compound and then carrying out a polymerization reaction.

The dispersed particle size distribution of the styrene resin composition obtained at this time is such that the type of the raw material styrene-butadiene block copolymer or methyl methacrylate-styrene-butadiene graft rubber particles used, the compounding amount, and the chain transfer agent used. It can be adjusted by the kind, the amount used, the reaction conditions of the polymerization reactor (reaction temperature, stirring speed, residence time, etc.).

The styrene-based resin composition of the present invention can also be produced by blending the rubber-modified styrene-based resin (A) and the component (B) with an extruder or the like.

In this case, the styrene resin composition of the present invention can be obtained by adjusting the dispersed particle size distribution in the component (A) used.

Regarding the particle size distribution of the dispersed particles in the composition of the present invention, it is necessary that the dispersed particles having a particle size of less than 0.4 μ are 75% by weight or more. In addition, it is necessary that the dispersed particles having a particle size of 0.4 to 2.1 μ are 5 to 25% by weight. If this ratio is less than 5% by weight, impact resistance is lowered, and if it exceeds 25% by weight, appearance characteristics are deteriorated. Is reduced. Further, it is necessary that the dispersed particles exceeding 2.1μ be 10% by weight or less, and if this ratio exceeds 10% by weight, the appearance characteristics are significantly deteriorated.

[Effects of the Invention] The styrene resin composition of the present invention has an impact resistance and a surface gloss with a good taste, and also has excellent processing fluidity, heat resistance, and rigidity. It is useful because it has the advantage that it can sufficiently meet the requirements for thinning of electrical product materials or various industrial materials, and also improve the physical strength and working fluidity.

[Examples] The present invention will be described in more detail with reference to Examples.

Example 1 As a polybutadiene rubber, low-cis polybutadiene having a 1,2 vinyl content of 12% (trade name: Diene NF-35AS, manufactured by Asahi Kasei Corporation) 6.0% by weight, mineral oil 0.5% by weight, 1,1 bis (t-butyl) -Peroxy) 0.03% by weight of 3,3,5-trimethylcyclohexane, 0.02% by weight of n-dodecylmercaptan, 6.0% by weight of ethylbenzene, and 100 parts by weight of a raw material solution containing a residual amount of styrene monomer, to a linear styrene. -Butadiene copolymer (styrene content 30% by weight, Shell Chemical Co., Ltd., trade name Califlex TR-1102)
5 parts by weight was added to prepare a uniform solution.

This raw material solution was continuously fed at a rate of 38.5 kg / hour to a first polymerization vessel having an internal volume of 50.5 l, which was maintained at a temperature of 120 ° C. and a stirring rotational speed of 240 rpm.

Next, the extract from the first polymerization reactor was continuously fed at the same speed (38.5 kg / hour) to the second polymerization reactor having an internal volume of 73 l and stirring rotation speed of 30 rpm. Further, at the same speed, the liquid was continuously fed to a third polymerization vessel having an internal volume of 73 l and stirring speed of 10 rpm.

The first polymerizer is a perfect mixing type equipped with spiral band blades, and the second and third polymerizers are linear flow tower type, with temperature gradients of 130 to 140 ° C and 150 to 180 ° C in the flow direction, respectively. The temperature was maintained so that it would stick. The polymer conversion rates at the outlets of the first to third polymerization vessels in the steady state were 20.2%, 60.5%, and 91.6%, respectively.

The polymerization reaction liquid continuously withdrawn from the third polymerization vessel is passed through a devolatilization step to remove unreacted monomer solvent under high temperature and high vacuum, and then pelletized by an extruder to obtain the composition. Obtained.

Example 2 The procedure of Example 1 was repeated except that 10 parts by weight of styrene-butadiene copolymer (TR-1102) was added.

Example 3 Linear styrene-butadiene copolymer having a styrene content of 40% by weight (Tafprene A, trade name, manufactured by Asahi Chemical Industry Co., Ltd.) 5
The same procedure as in Example 1 was carried out except that parts by weight were added.

Example 4 Example 4 was carried out in the same manner as in Example 3 except that 10 parts by weight of the styrene-butadiene copolymer (Toughprene A) was added.

Example 5 Branched styrene-butadiene copolymer (styrene content 30
Weight%, Shell Chemical Co., Ltd., trade name Califlex TR
-1184) was added in the same manner as in Example 1 except that 5 parts by weight was added.

Example 6 It carried out like Example 5 except having added 10 parts of styrene-butadiene copolymers (TR-1184).

Example 7 and Example 8 Instead of the styrene-butadiene copolymer, MBS (methyl methacrylate / styrene / butadiene graft rubber particles, rubber content 70% by weight, average particle diameter 0.3μ, trade name manufactured by Mitsubishi Rayon Co., Ltd. Metabrene C-223) was added in the same manner as in Example 1 except that 5 parts by weight or 10 parts by weight of Metablen C-223) was added and an emulsion-like solution was used as a raw material. In this case, the average particle diameter was determined by the area average diameter Ds of 1000 rubber particles.

Example 9 and Example 10 In Example 1, instead of the styrene-butadiene copolymer, (MBS methyl methacrylate-styrene-butadiene graft rubber particles: rubber content 70% by weight, average particle size
0.1μ, Kanefuchi Chemical Co., Ltd., trade name Kane Ace B-56)
Was added in an amount of 5 parts by weight or 10 parts by weight, respectively, and an emulsion-like solution was used as a raw material.

Example 11 In Example 1, a HIPS having a particle size distribution shown below was produced without adding a styrene-butadiene copolymer.

Particle size distribution R <0.4μ 68.9 (wt%) 0.4μ ≦ R ≦ 2.1μ 30.1 (wt%) R> 2.1μ 1.0 (wt%) Linear styrene-butadiene copolymer weight against 100 parts by weight of this HIPS Combined (Califlex TR-1102 R) 3 parts by weight, M
3 parts by weight of BS (metabrene C-223 R) was blended and blended with an extruder with a 50 mm screw to obtain the composition.

Example 12 Polybutadiene rubber (1,2 vinyl content 17%, low cis polybutadiene rubber, manufactured by Asahi Kasei Kogyo KK, trade name Asaprene 700A) 6.0 parts by weight 55.5 parts by weight styrene 18.5 parts by weight acrylonitrile (styrene / acrylonitrile weight (75/25 ratio) 100 parts by weight of raw material solution dissolved in 20.0 parts by weight of ethylbenzene, linear styrene-butadiene copolymer (styrene content 30% by weight, Shell Chemical Co., Ltd.)
5 parts by weight of Califlex TR-1102 (trade name, manufactured by Calif.), 0.01 part by weight of n-dodecyl mercaptan and 0.02 part by weight of benzoyl peroxide were added to prepare a uniform solution.

This raw material solution was maintained at a temperature of 110 ° C. and a stirring speed of 280 rpm at a rate of 42.1 kg / hour. Liquid was continuously fed to the first polymerization vessel having an inner volume of 50.5 l. Then, the polymerization reaction liquid continuously withdrawn from the first polymerization vessel was supplied to the second and third polymerization vessels to continue the polymerization.

The first polymerizer was a complete mixing type with a spiral band stirring blade. The second and third polymerizers are linear flow tower type, both have an internal volume of 73 l, and are 120 to 14 each in the flow direction.
The temperature was maintained so that there was a temperature gradient of 0 ° C and 150-180 ° C. The polymer conversion rates at the outlets of the first to third polymerization vessels in the steady state were 24.8%, 60.2%, and 89.2%, respectively.

The polymerization reaction solution continuously withdrawn from the third polymerization vessel is passed through a devolatilization step to remove unreacted monomer solvent under high temperature and high vacuum, and then pelletized by an extruder to obtain the composition. It was

Example 13 Example 13 was carried out in the same manner as in Example 12 except that 10 parts by weight of the styrene-butadiene copolymer (TR-1102) was added.

Example 14 The procedure of Example 12 was repeated, except that 8 parts by weight of MBS (Kaneace B-56) was added instead of the styrene-butadiene copolymer, and an emulsion solution was used as a raw material.

Example 15 In Example 12, ABS was produced without adding the styrene-butadiene copolymer. By this method, ABS having a particle size distribution shown below was obtained.

Particle size distribution R <0.4μ 66.7 (wt%) 0.4μ ≦ R <2.1μ 33.1 (wt%) R ≧ 2.1μ 0.2 (wt%) 100 parts by weight of this ABS, linear styrene-butadiene co-weight Combined (Califlex TR-1102) 3 parts by weight, MBS
3 parts by weight of (metabrene C-223) was blended and blended by an extruder with a 50 mm screw to obtain the composition.

The results of the above examples are shown in Table 1.

Comparative Examples 1 to 4 (Method for Enlarging HIPS Rubber Particles) In Example 1, 0.04% by weight of n-dodecyl mercaptan was used, and the same operation was performed with the stirring speed of the first polymerizer being 150 rpm.

Comparative Examples 6 and 7 (ABS Rubber Particle Enlargement Method) In Example 12, 0.03 parts by weight of n-dodecyl mercaptan was used, and the same operation was performed with the stirring speed of the first polymerizer being 120 rpm.

Comparative Example 5 The same operation as in Example 1 was performed except that the styrene-butadiene copolymer was not added and 0.04% by weight of n-dodecyl mercaptan was used, and the stirring speed of the first polymerization vessel was 150 rpm.

By this method, HIPS having the particle size distribution shown below was obtained.

Particle size distribution R <0.4μ 51.2 (wt%) 0.4μ ≦ R <2.1μ 42.1 (wt%) R ≧ 2.1μ 6.7 (wt%) For 100 parts by weight of this HIPS, linear styrene-butadiene copolymer (Califlex TR-1102) 3 parts by weight, MBS
3 parts by weight of (metabrene C-223) was blended and blended with an extruder with a 50 mm screw to obtain the composition.

The results of the above comparative examples are shown in Table 2.

From the results of the examples in Table 1, the resins of the examples have a melt flow rate of 1 g / 10 minutes or more and an Izod impact strength of 1 or more.
It is recognized that it is 0 kg cm / cm or more, the flexural modulus is 23,000 kg / cm ² or more, the gloss is 90% or more, and the heat distortion temperature is 90 ° C. or more.

From the results of Comparative Example in Table 2, Comparative Example 1 and Comparative Example 2
The same as Example 1 and Example 2 except that the rubber particle size of HIPS was increased, and the comparative example was inferior in fluidity, flexural modulus, heat distortion temperature and gloss.

Comparative Example 3 and Comparative Example 4 are the same as Example 7 and Example 8 except that the rubber particle size of HIPS was increased, and the comparative example is inferior in fluidity, flexural modulus, heat distortion temperature and gloss. .

Similar results were obtained between Comparative Example 5 and Example 11.

Comparative Example 6 and Comparative Example 7 are the same as Example 14 and Example 15 except that the rubber particle size of ABS was increased. Comparative Example 6 had low fluidity and Comparative Example 7 had poor gloss.

Claims (1)

[Claims] 1. A rubber-modified styrene resin 98 to 80% by weight and [B] (a) a styrene butadiene block copolymer rubber and (b) a methyl methacrylate-styrene-butadiene graft rubber. A styrene resin composition comprising 2 to 20% by weight of at least one kind of rubber particles, wherein the dispersed particles comprising the rubber component in the resin composition have a particle size of less than 0.4 µm of 75% by weight or more. Diameter
A styrene-based resin composition characterized by having a particle size distribution of 0.4 to 2.1 μm in an amount of 5 to 25% by weight and particles having a particle size of more than 2.1 μm in an amount of 10% by weight or less.