KR100583524B1 - High Impact Polystyrene Resin with Good Falling Dart Impact Prepared by Continuous Mass Polymerization process - Google Patents

Abstract

The high impact polystyrene resin of the present invention comprises 5 to 15% by weight of polymer (I) of styrene monomer and polybutadiene rubber 1 having a rubber particle diameter of 0.3 to 0.6 µm; 70 to 85% by weight of polymer (II) of the styrene monomer and the polybutadiene rubber 2 having a rubber particle diameter of 1.5 to 2.0 µm; And 5 to 20% by weight of polymer (III) of styrene-based monomer and polybutadiene-based rubber 3 having a diameter of 3.5 to 4.5 μm of rubber particles; and the size of rubber particles dispersed in the resin is trimodal. It is characterized by having.

At this time, the polybutadiene-based rubber 1, polybutadiene rubber 2, and polybutadiene rubber 3 has a 1,4-cis content of 43 wt%, 40 wt%, and 45 wt% or less, respectively; And the viscosity of the rubber solution prepared by mixing with 95% by weight of the styrene monomer is used 40 to 60 centipoise (centipoise), 155 to 185 centipoise (centipoise), and 190 to 250 centipoise (centipoise).

Description

High Impact Polystyrene Resin with Good Falling Dart Impact Prepared by Continuous Mass Polymerization process}             

1 is a process chart showing a bulk polymerization continuous process for producing a high impact polystyrene resin of the present invention.

Field of invention

The present invention relates to a high impact polystyrene resin excellent in drop impact strength. More specifically, the present invention relates to a high impact polystyrene resin having excellent drop impact strength by introducing the size of the rubber particles dispersed on the polystyrene resin in a trimodal form.

Background of the Invention

Styrene-based resins have been produced commercially a lot of excellent transparency, thermal stability, processability. In particular, a rubber-modified polystyrene resin has been developed by introducing rubber particles into a styrene resin to enhance impact resistance. This is called high impact polystyrene (HIPS). Such high impact polystyrene resins have a low Tg in rubber, especially cross-linked polybutadiene particles, such as styrene, alpha-methylstyrene, and ring-substituted styrene. It is dispersed in, and has good physical properties such as impact resistance, heat resistance, and fluidity, and is widely used as a housing for electrical and electronic products. In particular, as consumer preferences for large products have increased in recent years, home appliance companies have increased the output of large products, and at the same time, measures to reduce the thickness of products have been attempted to reduce the weight and manufacturing cost of large products. However, when the thickness of the product is reduced, the drop impact strength is lowered, so there is a problem that a crack occurs in the appearance of the molded product even with a small impact. Therefore, resin manufacturers are researching to develop products having excellent drop impact strength to compensate for these disadvantages. HIPS is generally prepared by a bulk polymerization process of styrene containing dissolved rubber. Conventional HIPS manufacturing process prepared in a batch method has the advantage that the polymerization process takes place in a single reaction vessel, it is easy to control the overall polymerization process, but it is difficult to use commercially. In order to solve this problem, US Pat. No. 4,861,827 discloses a process that uses a specific free radical initiator and does not reduce the efficiency of the free radical initiator when the initiator is decomposed and recycled. However, HIPS produced by such a bulk polymerization continuous process has a problem in that the impact particle strength is not significantly improved because the size of rubber particles dispersed in the resin composition has a monomodal or bimodal form. have.

Accordingly, the present inventors have developed a rubber-modified polystyrene resin having excellent drop impact strength by introducing a rubber particle size dispersed in a polystyrene resin composition in a trimodal form in order to solve the above problems.

An object of the present invention is to provide a high impact polystyrene resin excellent in drop impact strength by introducing the size of the rubber particles introduced into the high impact polystyrene resin in a trimodal form.

The above and other objects of the present invention can be achieved by the present invention described below.

Hereinafter, the content of the present invention will be described in detail.

The high impact polystyrene resin of the present invention comprises 5 to 15% by weight of polymer (I) of styrene monomer and polybutadiene rubber 1 having a rubber particle diameter of 0.3 to 0.6 µm; 70 to 85% by weight of polymer (II) of the styrene monomer and the polybutadiene rubber 2 having a rubber particle diameter of 1.5 to 2.0 µm; And 5 to 20% by weight of polymer (III) of styrene-based monomer and polybutadiene-based rubber 3 having a diameter of 3.5 to 4.5 μm of rubber particles; and the size of rubber particles dispersed in the resin is trimodal. Have

1 is a process chart showing a bulk polymerization continuous process for producing a high impact polystyrene resin of the present invention.

The styrene monomer and the polybutadiene rubber 1 are mixed in the R-1-1 reactor and polymerized at 110 to 140 ° C. for 1.5 to 2.5 hours at a conversion rate of 20 to 30%. In this case, the styrene monomers used are styrene, α-methyl styrene, α-ethyl styrene, ρ-methyl styrene, and the like, and polybutadiene rubber 1 has a 1,4-cis content of 43 wt% or less and 95 parts by weight of styrene. The viscosity of the rubber solution consisting of the monomer and 5 parts by weight of the polybutadiene rubber 1 is 40 to 60 centipoise level. Polymer (I) polymerized in the R-1-1 reactor has a rubber particle diameter of 0.3 to 0.6 mu m.

In the R-1-2 reactor, a styrene monomer and a polybutadiene rubber 2 are mixed and polymerized at 110 to 140 ° C. for 1.5 to 2.5 hours at a conversion rate of 20 to 30%. In this case, the styrene monomer used is the same as the monomer used in the polymer (I), polybutadiene rubber 2 has a 1,4-cis content of 40% by weight or less, 95 parts by weight of styrene monomer and 5 parts by weight of the The viscosity of the rubber solution consisting of polybutadiene-based rubber 2 is 155 to 185 centipoise level. Polymer (II) polymerized in the R-1-2 reactor has a rubber particle diameter of 1.5 to 2.0 mu m.

In the R-1-3 reactor, the styrene monomer and the polybutadiene rubber 3 are mixed and polymerized at 110 to 140 ° C. for 1.5 to 2.5 hours at a conversion rate of 20 to 30%. In this case, the styrene monomer used is the same as the monomer used in the polymer (I), polybutadiene-based rubber 3 has a 1,4-cis content of 45% by weight or less, 95 parts by weight of styrene monomer and 5 parts by weight of the The viscosity of the rubber solution consisting of polybutadiene-based rubber 3 is 190 to 250 centipoise level. Polymer (II) polymerized in the R-1-2 reactor has a rubber particle diameter of 3.5 to 4.5 µm.

 The polymer (I), the polymer (II), and the polymer (III) are mixed and then further polymerized to prepare in the R-2 reactor and the R-3 reactor.

That is, the polymer (I), the polymer (II), and the polymer (III) introduced into the R-2 reactor are polymerized at 150 to 180 ° C. for 1 to 2 hours, at 35% conversion of mineral oil, antioxidant, and A molecular weight modifier is added to achieve a conversion of 45-50%. The polymer transferred through the R-2 reactor is introduced into the R-3 reactor and polymerized at 170 to 200 ° C. for 0.5 to 1.5 hours to obtain a conversion of 70 to 75%.

The devolatilizer recovers unreacted monomers and sends them to a condensation condenser. When the process is completed, a high impact polystyrene (HIPS) resin having a conversion rate of 99.9% is prepared. The high impact polystyrene (HIPS) resin prepared as described above is rubber particles dispersed in a trimodal form.

The high impact polystyrene resin of the present invention can be more clearly understood by the following examples, the following examples are merely for illustrative purposes of the present invention and are not intended to limit the scope of the invention.

Example 1 Preparation of Polymer (I)

91.5 parts by weight of styrene monomer and 8.5 parts by weight of polybutadiene-based rubber 1 were added, and 0.08 parts by weight of tertiary butyl peroxyacetate was added as an initiator, followed by polymerization at 116 ° C. for 2 hours to synthesize a polymer having a conversion ratio of 27%. At this time, the diameter of the rubber particles was 0.3 ~ 0.6 ㎛.

Example 2 Preparation of Polymer (II)

91.5 parts by weight of styrene monomer and 8.5 parts by weight of polybutadiene-based rubber 2 were added, and 0.07 parts by weight of tertiary butyl peroxyacetate was added as an initiator, followed by polymerization at 115 ° C. for 2 hours to synthesize a polymer having a conversion ratio of 26%. At this time, the diameter of the rubber particles was 1.5 to 2.0 ㎛.

Example 3 Preparation of Polymer (III)

91.5 parts by weight of styrene monomer and 8.5 parts by weight of polybutadiene-based rubber 3 were added, and 0.06 parts by weight of tertiary butyl peroxyacetate was added as an initiator, followed by polymerization at 116 ° C. for 2 hours to synthesize a polymer having a conversion ratio of 25%. At this time, the diameter of the rubber particles was 3.5 to 4.5 ㎛.

Example 4 Polymerization of High Impact Polystyrene Resins

5% by weight of polymer (I) synthesized in Example 1 (27% conversion), 85% by weight of polymer (II) synthesized in Example 2 (26% conversion), and polymer (III) synthesized in Example 3 ( 25% conversion) 10% by weight was mixed. A mineral oil, an antioxidant, and a molecular weight controlling agent were added and polymerized to have a conversion rate of 99.9% by using the bulk polymerization continuous process shown in FIG. 1. The rubber particle size dispersed in the resin was trimodal and the rubber content was 8.5% by weight. HIPS was prepared. After the injection molding machine by injection molding the test specimen, the physical properties were measured and the results are shown in Table 1.

Example 5 Polymerization of High Impact Polystyrene Resins

It carried out similarly to Example 4 except using 10 weight% of polymers (I), 70 weight% of polymers (II), and 20 weight% of polymers (III). As a result, HIPS having a rubber particle size of trimodal form and rubber content of 8.5% was prepared, and the results are shown in Table 1 below.

Example 6 Polymerization of High Impact Polystyrene Resin

It carried out similarly to Example 4 except using 15 weight% of polymers (I), 80 weight% of polymers (II), and 5 weight% of polymers (III). As a result, HIPS having a rubber particle size of trimodal form and rubber content of 8.5% was prepared, and the results of the measurement are shown in Table 1.

Comparative Example 1

It carried out similarly to Example 4 except using 50 weight% of polymers (I) and 50 weight% of polymers (II). As a result, HIPS having a rubber particle size of bimodal form and rubber content of 8.5% was prepared, and the results are shown in Table 1 below.

Comparative Example 2

It carried out similarly to Example 4 except using 50 weight% of polymers (I) and 50 weight% of polymers (III). As a result, HIPS having a rubber particle size of bimodal form and rubber content of 8.5% was prepared, and the results are shown in Table 1 below.

Comparative Example 3

It carried out similarly to Example 4 except using 50 weight% of polymers (II) and 50 weight% of polymers (III). As a result, HIPS having a rubber particle size of bimodal form and rubber content of 8.5% was prepared, and the results are shown in Table 1 below.

Comparative Example 4

It carried out similarly to Example 4 except using 100 weight% of polymers (I). As a result, HIPS with a rubber particle size of monomodal form and rubber content of 8.5% was prepared, and the results are shown in Table 1 below.

Comparative Example 5

It carried out similarly to Example 4 except using 100 weight% of polymers (II). As a result, HIPS with a rubber particle size of monomodal form and rubber content of 8.5% was prepared, and the results are shown in Table 1 below.

Comparative Example 6

It carried out similarly to Example 4 except using 100 weight% of polymers (III). As a result, HIPS with a rubber particle size of monomodal form and rubber content of 8.5% was prepared, and the results are shown in Table 1 below.

Item Example Comparative example 4 5 6 One 2 3 4 5 6 Rubber with 0.3 ~ 0.6㎛ rubber particle diameter (wt%) 5 10 15 50 50 0 100 0 0 Polymer with rubber particle diameter of 1.5 ~ 2.0㎛ (% by weight) 85 70 80 50 0 50 0 100 0 Polymer with rubber particle size of 3.5 to 4.5㎛ (% by weight) 10 20 5 0 50 50 0 0 100 Rubber content (% by weight) 8.5 8.5 8.5 8.5 8.5 8.5 8.5 8.5 8.5 Tensile Strength (kgcm / kg) 302 314 327 331 319 305 338 312 295 % Elongation 94 98 87 58 69 105 51 99 112 Fluidity (g / 10min.) 3.5 3.6 3.4 3.4 3.6 3.4 3.5 3.5 3.4 Drop impact strength (Joule) 21.3 19.8 18.9 7.6 10.6 8.9 1.8 11.4 7.9

Tensile strength was measured according to ASTM D638 (test speed: 20 mm / min);

Elongation was measured according to ASTM D638 (test speed: 20 mm / min);

Fluidity was evaluated according to ASTM D1238 (200 ° C., 5 kg); And

Drop impact strength was measured according to JIS K7211.

As a result of measuring the physical properties, in Examples 4 to 6 in which rubber particles were introduced in three different diameters, the rubber particles were dispersed in a polymodal resin in a trimodal form to exhibit excellent drop impact strength. It can be seen that the comparative examples 1 to 6 introduced in the monomodal or bimodal form significantly reduced the drop impact strength.

The high impact polystyrene resin of the present invention has an effect of excellent drop impact strength by dispersing rubber particles in a polymodal form in a polystyrene resin by preparing three kinds of polymers having different diameters of rubber particles and polymerizing them again.

Simple modifications and variations of the present invention can be readily used by those skilled in the art, and all such variations or modifications can be considered to be included within the scope of the present invention.

Claims (4)

5 to 15% by weight of polymer (I) of styrene-based monomer and polybutadiene-based rubber 1 having a rubber particle diameter of 0.3 to 0.6 mu m; 70 to 85% by weight of polymer (II) of the styrene monomer and the polybutadiene rubber 2 having a rubber particle diameter of 1.5 to 2.0 µm; And a bulk polymerization of 5 to 20% by weight of polymer (III) of the styrene-based monomer having a diameter of 3.5 to 4.5 µm and the polybutadiene-based rubber 3, wherein the rubber particles dispersed in the resin have a trimodal form. High impact polystyrene resin, characterized in that. The high impact polystyrene resin according to claim 1, wherein the styrene monomer is selected from the group consisting of styrene, α-methyl styrene, α-ethyl styrene, and ρ-methyl styrene. According to claim 1, wherein the polybutadiene-based rubber 1 has a 1,4-cis content of 43% by weight or less, the viscosity of the rubber solution mixed with 95% by weight of the styrene monomer is 40 to 60 centipoise; The polybutadiene rubber 2 has a 1,4-cis content of 40 wt% or less, and a viscosity of the rubber solution mixed with 95 wt% of a styrene monomer is 155 to 185 centipoise; And The polybutadiene rubber 3 has a 1,4-cis content of 45% by weight or less and a viscosity of the rubber solution mixed with 95% by weight of a styrene monomer of 190 to 250 centipoise; High impact polystyrene resin, characterized in that. A polymer of styrene monomer and polybutadiene rubber 1 having a diameter of 0.3 to 0.6 µm by polymerizing styrene monomer and polybutadiene rubber at a conversion rate of 20 to 30% at 110 to 140 ° C. for 1.5 to 2.5 hours. I), the polymer of the styrene monomer and the polybutadiene rubber 2 of the rubber particle diameter of 1.5-2.0 micrometers (II), and the polymer of the styrene monomer and the polybutadiene rubber 3 of the rubber particle diameter of 3.5-4.5 micrometers (III) were each prepared; Transferring the polymer (I), the polymer (II) and the polymer (III) to the R-2 reactor and polymerizing at 150 to 180 ° C. for 1 to 2 hours; And Introducing the polymerized polymer into an R-3 reactor to polymerize at 170 to 200 ° C. for 0.5 to 1.5 hours; Method for producing a high impact polystyrene resin, characterized in that consisting of steps.

Images