A high-impact polystyrene resin, its preparation method and use

Abstract

The application discloses a kind of high impact polystyrene resin and preparation method and application, the resin is made of raw materials including as follows: styrene monomer 83~87wt%, composite rubber 7~11wt%, mineral oil 0.7~3.2wt%, zinc stearate 0.5~2.8wt%;Wherein, the composite rubber includes the first particle with particle size 0.1~1 μm and the second particle with particle size 1~6 μm, the mass ratio of the first particle and the second particle is 15~30:70~85.The preparation method provided by the application adopts multiple reactor and controls reaction parameter gradually, and focuses on adjusting the stirring speed in the process of pre-polymerization of composite rubber type, so that the prepared resin has higher gloss and better mechanical properties.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of high polymer materials, in particular, relates to a high impact polystyrene resin and its preparation method and application. BACKGROUND

[0002] HIPS refers to impact polystyrene, which is connected together by adding micron-sized rubber particles in the polystyrene polymerization process and grafting through chemical reaction. When the material is impacted, the stress of crack propagation will be absorbed by the soft rubber particles, so that the crack propagation is hindered, and the impact resistance is improved.

[0003] HIPS is one of the cheapest engineering plastics, and compared with ABS, PC / ABS and PC, the material has poor gloss and relatively poor comprehensive performance. In recent years, the newly developed special HIPS products have been able to compete with engineering resins in related application fields, and have shown significant growth in the consumer electronics and instrument industries, such as refrigerator parts, television housings, air conditioner housings and small instruments. Special grade HIPS resin has a trend of replacing high-cost engineering plastics in some related fields.

[0004] HIPS has the characteristics of easy processing, low cost and good performance, and in view of the demand of the home appliance industry, special grade HIPS materials have also appeared on the market one after another, and many home appliance manufacturers have used them to make various panel and door plate appearance parts. However, the HIPS materials on the market cannot balance the flowability, impact toughness and gloss at present, which will inevitably limit the application of HIPS materials in this field.

[0005] Japanese Patent Publication No. 4-100810 points out a method of using two different cis-content rubber polymers to control the rubber particle size, and the resin of the Japanese patent application achieves good impact strength, but the surface gloss is not good; U.S. Patent 4839418 of Schwaben et al. discloses a thermoplastic molding material composed of a hard polystyrene matrix and a soft phase, which is distributed in the hard phase and has a particle size of less than 0.8 μm. Although the molding material has good gloss, it has the disadvantage of low impact strength. SUMMARY

[0006] The technical problem to be solved by the present application is to overcome the shortcomings of the prior art and provide a high impact polystyrene resin and its preparation method and application. By adjusting the composite mode and particle composition of the rubber component, the prepared resin material has higher gloss and better mechanical properties. The material has low cost and excellent performance, and can bring wider application fields and greater profit space to the home appliance industry.

[0007] To solve the above technical problems, the basic idea of the technical solution of the present application is:

[0008] The first object of the present application is to provide a high impact polystyrene resin made from raw materials comprising:

[0009]

[0010] The rubber comprises first particles with a particle size of 0.1-1 μm and second particles with a particle size of 1-6 μm, and the mass ratio of the first particles to the second particles is 70-85:15-30.

[0011] In a further aspect of the high impact polystyrene resin, the composite rubber is selected from one or more of three different types of rubber, i.e. a first rubber with a Mooney viscosity ML(1+4) of 45-55 and a solution viscosity of 150-190 cps, a second rubber with a Mooney viscosity ML(1+4) of 40-50 and a solution viscosity of 30-40 cps, and a third rubber with a Mooney viscosity ML(1+4) of 40-50 and a solution viscosity of 10-20 cps.

[0012] In a further aspect of the high impact polystyrene resin, the rubber is selected from one or more of linear low-cis polybutadiene rubber, star-shaped low-cis polybutadiene rubber, or styrene-butadiene-styrene block copolymer.

[0013] In a further aspect of the high impact polystyrene resin, the mineral oil is composed of alkanes and cycloalkanes with a molecular weight of not less than 480, and is refined to remove impurities such as aromatic hydrocarbons, sulfur and nitrogen.

[0014] In a further aspect of the high impact polystyrene resin, the average particle size of the zinc stearate is 0.2-7 μm.

[0015] The second object of the present application is to provide a method for preparing the high impact polystyrene resin as described above, comprising the following steps:

[0016] (1) Dissolving the mineral oil and the composite rubber in styrene monomers to prepare a composite rubber solution, and then feeding the solution into a first prepolymerization reactor;

[0017] (2) Adding an initiator into the first prepolymerization reactor, and carrying out polymerization at a temperature of 106-126 °C with a stirring speed of 80-90 rpm, and then feeding the solution into a second prepolymerization reactor when the solid content reaches 10-25 wt%;

[0018] (3) the reaction temperature of the second prepolymerization reactor is controlled to be 115-135 DEG C, the stirring speed is 40-45 rpm, and when the solid content reaches 25-35 wt%, the melt polymer is sent into the multi-stage polymerization reactors arranged in sequence, the reaction temperature of which is in the range of 140-180 DEG C and gradually increases, and the temperature of the last stage of the polymerization reactor is controlled to be 173-180 DEG C, and the solid content of the multi-stage polymerization reactors is controlled to gradually increase in steps;

[0019] (4) when the solid content of the styrene monomer in the last stage of the polymerization reactor reaches 70-80 wt%, the melt polymer is sent into the devolatilization system to remove and recover the unreacted monomer and solvent, and then the high impact polystyrene resin is prepared through extrusion, cooling and granulation.

[0020] According to the above preparation method, the multi-stage polymerization reactor comprises a first polymerization reactor, a second polymerization reactor and a third polymerization reactor arranged in sequence, and the reaction temperature is 140-160 DEG C, 150-165 DEG C and 173-180 DEG C in sequence, and the solid content of the styrene monomer is 40-50 wt%, 50-60 wt% and 65-75 wt% in sequence.

[0021] According to the above preparation method, the reaction pressure of the first prepolymerization reactor is 50-70 kPa, the pressure of the second prepolymerization reactor is 53.3-66.7 kPa, the pressure of the multi-stage polymerization reactor is 100-300 kPa, and the pressure of the devolatilization system is 2-4 kPa.

[0022] According to the above preparation method, the stirring speed of the first prepolymerization reactor is 80-90 rpm, the stirring speed of the second prepolymerization reactor is 40-45 rpm, and the stirring speed of the multi-stage polymerization reactor is 1.5-15 rpm.

[0023] According to the above preparation method, the antioxidant is added when the composite rubber is dissolved in step (1), and the zinc stearate is added in the second polymerization reactor in step (3).

[0024] The high impact polystyrene resin provided by the application can be widely applied to the housings of household appliances, so that the household appliances have higher glossiness and excellent impact resistance and related mechanical properties.

[0025] Compared with the prior art, the application has the following beneficial effects:

[0026] The method of the application can produce the resin suitable for forming high-impact and high-gloss products, at least one or two different rubber particles are dispersed in the polystyrene matrix, the average particle size of the dispersed rubber particles is about 0.1-1 μm and 1-6 μm, and the method is easy to be carried out in large scale and continuously.

[0027] The specific embodiments of the present application will be further described in conjunction with the drawings. BRIEF DESCRIPTION OF DRAWINGS

[0028] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate exemplary embodiments of the application and together with the description, serve to explain the application. Obviously, the drawings are only some embodiments of the application and other drawings can be obtained by those skilled in the art without any creative effort on the basis of these drawings. In the drawings:

[0029] Figure 1 is a schematic diagram of the production system used in the present application for preparing high impact polystyrene resin;

[0030] Figure 2 is a STEM image of the high impact polystyrene resin prepared in Example 1 of the present application;

[0031] Figure 3 is a diagram of the rubber particle size and its distribution of the high impact polystyrene resin prepared in Example 1 of the present application;

[0032] Figure 4 is a STEM image of the high impact polystyrene resin prepared in Example 2 of the present application;

[0033] Figure 5 is a diagram of the rubber particle size and its distribution of the high impact polystyrene resin prepared in Example 2 of the present application;

[0034] Figure 6 is a STEM image of the high impact polystyrene resin prepared in Example 3 of the present application;

[0035] Figure 7 is a diagram of the rubber particle size and its distribution of the high impact polystyrene resin prepared in Example 3 of the present application;

[0036] It should be noted that these drawings and written descriptions are not intended to limit the scope of the concept of the present application in any way, but to illustrate the concept of the present application to those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0037] In order to make the purpose, technical solutions and advantages of the embodiments of the present application more clear, the technical solutions in the embodiments will be described clearly and completely in conjunction with the drawings of the embodiments of the present application. The following embodiments are used to illustrate the present application, but not to limit the scope of the present application.

[0038] Example 1

[0039] In this embodiment, the high impact polystyrene resin is prepared by the following method:

[0040] (1) Preparation of the feed solution: 2.7wt% of mineral oil, 7.8wt% of linear low-cis polybutadiene rubber with a Mooney viscosity ML(1+4) of 55 and a solution viscosity of 150cps, were dissolved in 87wt% of styrene monomer to prepare a rubber solution which was then fed into the first prepolymerization reactor as the feed solution, wherein the linear low-cis polybutadiene rubber included first particles with a particle size of 0.5μm and second particles with a particle size of 4μm, and the mass ratio of the first particles to the second particles was 70:30;

[0041] (2) Continuous polymerization: 100ppm of initiator was added to the first prepolymerization reactor, and after polymerization was carried out at a reaction temperature of 116°C and a stirring speed of 90rpm to reach a solid content of 15wt%, the product was sent to the second prepolymerization reactor;

[0042] (3) Control of the reaction temperature of the second prepolymerization reactor to be 125°C, and carry out polymerization at a stirring speed of 45rpm to reach a solid content of 33wt%, and then send the product to the subsequent multi-stage polymerization reactors with gradually increased reaction temperatures of 140-180°C, wherein the multi-stage polymerization reactors included a first polymerization reactor, a second polymerization reactor and a third polymerization reactor arranged in sequence, and the reaction temperatures were 160°C, 165°C and 178°C in sequence; wherein 2.5wt% of zinc stearate based on the feed solution was added before the second stage polymerization reactor; the first stage polymerization reactor was polymerized to a solid content of 45wt%; the second stage polymerization reactor was polymerized to a solid content of 55wt%; and the third stage polymerization reactor was continuously polymerized to a solid content of 70wt%;

[0043] (4) Devolatilization: the molten polymer from the third stage polymerization reactor was sent to a devolatilization system, and after removing and recovering unreacted monomers and solvents at 240°C, the product was extruded, cooled, cut and pelletized to obtain a high-gloss HIPS product resin.

[0044] Example 2

[0045] (1) Preparation of the feed solution: 3.2wt% of mineral oil, 6.9wt% of linear low-cis polybutadiene rubber with a Mooney viscosity ML(1+4) of 50 and a solution viscosity of 190cps, 2.4wt% of star-shaped low-cis polybutadiene rubber with a Mooney viscosity ML(1+4) of 40 and a solution viscosity of 35cps, were dissolved in 87wt% of styrene monomer to prepare a rubber solution which was then fed into the first prepolymerization reactor as the feed solution, wherein the composite rubber of the linear low-cis polybutadiene rubber and the star-shaped low-cis polybutadiene rubber included first particles with a particle size of 0.1μm and second particles with a particle size of 1μm, and the mass ratio of the first particles to the second particles was 85:15;

[0046] (2) Continuous polymerization: 100 ppm of initiator was added to the first prepolymerization reactor, and polymerization was carried out at a reaction temperature of 116°C and a stirring speed of 85 rpm to reach a solid content of 15 wt%, and then the product was sent to the second prepolymerization reactor;

[0047] (3) The reaction temperature of the second prepolymerization reactor was controlled at 135°C, and the stirring speed was 42 rpm, and polymerization was carried out to reach a solid content of 25 wt%, and then the product was sent to the subsequent multi-stage polymerization reactors with gradually increasing reaction temperatures of 140-180°C, which included a first polymerization reactor, a second polymerization reactor, and a third polymerization reactor arranged in sequence, with reaction temperatures of 140°C, 155°C, and 180°C, respectively; wherein 0.5 wt% of zinc stearate based on the feed liquid was added before the second polymerization reactor; the first polymerization reactor was polymerized to a solid content of 45 wt%; the second polymerization reactor was polymerized to a solid content of 55 wt%; and the third polymerization reactor was further polymerized to a solid content of 70 wt%;

[0048] (4) Devolatilization: the molten polymer from the third polymerization reactor was sent to a devolatilization system, and after removing and recovering unreacted monomers and solvents at 240°C, the product was extruded, cooled, and cut into particles to obtain a high-gloss HIPS product resin.

[0049] Example 3

[0050] (1) Preparation of the feed liquid: 0.7 wt% of mineral oil, 8.75 wt% of linear low-cis polybutadiene rubber with a Mooney viscosity ML(1+4) of 45 and a solution viscosity of 170 cps, and 2.75 wt% of styrene-butadiene-styrene block copolymer with a Mooney viscosity ML(1+4) of 45 and a solution viscosity of 15 cps were dissolved in 85.8 wt% of styrene monomer to prepare a rubber solution, which was then sent to the first prepolymerization reactor as the feed liquid; the complex rubber of the linear low-cis polybutadiene rubber and the styrene-butadiene-styrene block copolymer included first particles with a particle size of 1 μm and second particles with a particle size of 6 μm, and the mass ratio of the first particles to the second particles was 75:25;

[0051] (2) Continuous polymerization: 100 ppm of initiator was added to the first prepolymerization reactor, and polymerization was carried out at a reaction temperature of 116°C and a stirring speed of 85 rpm to reach a solid content of 15 wt%, and then the product was sent to the second prepolymerization reactor;

[0052] (3) Control the second prepolymerization reactor to carry out polymerization to 35 wt% solid content at a reaction temperature of 115°C and a stirring speed of 40 rpm, and then send to the subsequent multi-stage polymerization reactors with gradually increased reaction temperatures of 140-180°C, the multi-stage polymerization reactors including a first polymerization reactor, a second polymerization reactor and a third polymerization reactor arranged in sequence, and the reaction temperatures being 145°C, 150°C and 173°C in sequence; wherein 2.5 wt% of zinc stearate in the feed liquid is added before the second polymerization reactor; the first polymerization reactor is polymerized to 45 wt% solid content; the second polymerization reactor is polymerized to 55 wt% solid content; and the third polymerization reactor is continuously polymerized to 70 wt% solid content;

[0053] (4) Devolatilization: send the molten polymer from the third polymerization reactor to a devolatilization system, after removing and recovering unreacted monomers and solvents at 240°C, extrude, cool, cut and pelletize to obtain the high-gloss HIPS product resin.

[0054] Comparative Example 1

[0055] This comparative example is based on Example 2, and the mass ratio of the first particles to the second particles in step (1) is adjusted to 87:13, and the other embodiments of this comparative example are the same as those of Example 2.

[0056] Comparative Example 2

[0057] This comparative example is based on Example 1, and the mass ratio of the first particles to the second particles in step (1) is adjusted to 68:32, and the other embodiments of this comparative example are the same as those of Example 1.

[0058] Experimental Example 1

[0059] In this experimental example, the high-impact polystyrene resins prepared in Examples 1-3 are tested for performance, and the test items and test methods are as follows:

[0060] (1) Melt index: determined according to ASTM D1238 method, and the determination conditions are 200°C and 5 kg.

[0061] (2) Gloss: according to GB8807-88 "Plastic Mirror Gloss Test Method", which is the ratio of the mirror reflectivity of the sample to that of the reference surface under the same conditions at an incident angle of 60°.

[0062] (3) IZOD impact strength: cantilever beam notched impact strength, determined according to ASTM D256 method, and the determination conditions are 23°C and 1 / 8 inch thick injection molded sample with a notch.

[0063] (4) Vicat softening temperature: according to GB / T 1633-2000 "Determination of Vicat Softening Temperature (VST) of Thermoplastics", is when the uniform speed temperature, 10N or 50N force, heating rate of 50 or 120℃ / h under load conditions, the temperature of the standard pressure needle into the sample surface 1mm deep when the temperature.

[0064] (5) Rubber particle size: Malvern laser particle size analyzer is used, first with butanone to dissolve HIPS, and then particle size measurement.

[0065] (6) Solution viscosity: according to ASTM D2857 method, the determination conditions are 5% rubber styrene solution, 25℃.

[0066] The test results are as follows:

[0067]

[0068] In the above test results, the proportion of rubber particle size has a certain small difference from the proportion described in the examples and comparative examples, which is a small difference caused by the detection method, and will not affect the macro performance.

[0069] The above only describes the preferred embodiments of the present application, and does not limit the present application in any form. Although the present application has been disclosed as above, it is not intended to limit the present application. Any skilled person in the art can make some changes or modifications to the above-mentioned technical content without departing from the scope of the present application, and any simple modification, equivalent change and modification of the above-mentioned technical content, which does not depart from the technical solution of the present application, is still within the scope of the present application.

Claims

1. A high-impact polystyrene resin, characterized in that, Made from raw materials comprising the following components: 83-87 wt% styrene monomer Composite rubber 7-11 wt% Mineral oil 0.7–3.2 wt% Zinc stearate 0.5–2.8 wt% The composite rubber comprises a first particle with a particle size of 0.1 to 1 μm and a second particle with a particle size of 1 to 6 μm, wherein the mass ratio of the first particle to the second particle is 70 to 85: 15 to 30. The composite rubber is selected from one or more of three different types of rubber, namely, a first rubber with a Mooney viscosity ML(1+4) of 45-55 and a solution viscosity of 150-190 cps, a second rubber with a Mooney viscosity ML(1+4) of 40-50 and a solution viscosity of 30-40 cps, and a third rubber with a Mooney viscosity ML(1+4) of 40-50 and a solution viscosity of 10-20 cps; The average particle size of the zinc stearate is 0.2–7 μm; The raw materials also include initiators and antioxidants.

2. The high-impact polystyrene resin according to claim 1, characterized in that, The rubber is selected from one or more of linear low-cis polybutadiene rubber, star-shaped low-cis polybutadiene, and styrene-butadiene-styrene block copolymers.

3. The high-impact polystyrene resin according to claim 1, characterized in that, The mineral oil is composed of alkanes and cycloalkanes with a molecular weight of not less than 480, and is refined to remove impurities such as aromatic hydrocarbons, sulfur, and nitrogen.

4. A method for preparing the high-impact polystyrene resin as described in any one of claims 1 to 3, characterized in that, Includes the following steps: (1) Mineral oil and composite rubber are dissolved in styrene monomer to prepare a composite rubber solution, which is then fed into the first prepolymerization reactor. (2) Add the initiator to the first prepolymerization reactor and polymerize at a temperature of 106-126°C with a stirring speed of 80-90 rpm. When the solid content reaches 10-25 wt%, it enters the second prepolymerization reactor. (3) The reaction temperature of the second prepolymerization reactor is controlled at 115-135℃ and the stirring speed is 40-45 rpm. When the solid content reaches 25-35 wt%, it is sequentially fed into a multi-stage polymerization reactor with a reaction temperature of 140-180℃ that is gradually increased. The temperature of the last polymerization reactor is controlled at 173-180℃. The solid content of the multi-stage polymerization reactor is controlled to increase stepwise. The multi-stage polymerization reactor includes a first polymerization reactor, a second polymerization reactor and a third polymerization reactor arranged in sequence. Zinc stearate is added to the second polymerization reactor. (4) When the solid content of styrene monomer in the last stage polymerization reactor reaches 70-80 wt%, the molten polymer is sent to the devolatilization system to remove and recover unreacted monomers, and then extruded, cooled and granulated to obtain high-impact polystyrene resin.

5. The method for preparing the high-impact polystyrene resin according to claim 4, characterized in that, The multi-stage polymerization reactor includes a first polymerization reactor, a second polymerization reactor, and a third polymerization reactor arranged in sequence, with reaction temperatures of 140–160°C, 150–165°C, and 173–180°C, respectively, and styrene monomer solid contents of 40–50 wt%, 50–60 wt%, and 65–75 wt%, respectively.

6. The method for preparing high-impact polystyrene resin according to claim 4, characterized in that, In step (1), an antioxidant is added when the composite rubber is dissolved.

7. The method for preparing high-impact polystyrene resin according to claim 4, characterized in that, The reaction pressure of the first prepolymerization reactor is 50–70 kPa, the pressure of the second prepolymerization reactor is 53.3–66.7 kPa, the pressure of the multi-stage polymerization reactor is 100–300 kPa, and the pressure of the devolatilization system is 2–4 kPa.

8. The method for preparing high-impact polystyrene resin according to claim 4, characterized in that, The stirring speed of the first prepolymerization reactor is 80-90 rpm, the stirring speed of the second prepolymerization reactor is 40-45 rpm, and the stirring speed of the multi-stage polymerization reactor is 1.5-15 rpm.

9. The application of the high-impact polystyrene resin as described in any one of claims 1 to 3 in the casing of household appliances.

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