A styrene-butadiene copolymer composition, its preparation method and application

Abstract

This invention relates to a styrene-butadiene copolymer composition, its preparation method, and its applications, belonging to the field of polymer materials technology. The styrene-butadiene copolymer composition of this invention comprises the following components in parts by weight: 40-65 parts of styrene-butadiene copolymer, 9-34 parts of styrene-methyl methacrylate copolymer A, 20-40 parts of heat-resistant modifier, 5-10 parts of phase regulator, and 0.5-5 parts of haze regulator. This styrene-butadiene copolymer composition not only possesses good heat resistance but also high transparency and is easy to demold.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, and in particular to a styrene-butadiene copolymer composition, its preparation method, and its application. Background Technology

[0002] Styrene-butadiene copolymer (SB), also known as K-resin or K-polymer, is a copolymer of styrene and butadiene. It possesses excellent transparency, gloss, and impact resistance, and is widely used in various transparent products. However, styrene-butadiene copolymer has relatively poor heat resistance and generally cannot be used for extended periods at high temperatures, limiting its application in high-temperature fields. Currently, its heat resistance is mainly improved by adding high-rigidity polymers to styrene-butadiene copolymer for blending and modification. For example, prior art (CN109666240A) discloses a high-rigidity light-diffusing K-resin material and its preparation method, using styrene-butadiene copolymer as the matrix resin. It enhances the rigidity of the composite material by adding polystyrene and styrene-acrylonitrile copolymer to improve heat resistance, while using organosilicon light-diffusing agents to reduce the haze of the composite material. Although this improves the heat resistance of styrene-butadiene copolymer to some extent, it is difficult to maintain high transparency. Meanwhile, in practical applications, it has been found that compositions or composite materials prepared by blending and modifying polymers such as polystyrene, styrene-acrylonitrile copolymer, or styrene-methyl methacrylate copolymer with styrene-butadiene copolymer still have the problem of poor demolding performance (difficult to demold). Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of the prior art and provide a styrene-butadiene copolymer composition, its preparation method, and its application.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0005] In a first aspect, the present invention provides a styrene-butadiene copolymer composition, comprising, by weight parts: 40-65 parts of styrene-butadiene copolymer, 9-34 parts of styrene-methyl methacrylate copolymer A, 20-40 parts of heat-resistant modifier, 5-10 parts of phase modifier, and 0.5-5 parts of haze modifier;

[0006] The butadiene content in the styrene-butadiene copolymer is 25% to 30% by mass;

[0007] The weight percentage of styrene-butadiene copolymer in the styrene-butadiene copolymer composition is preferably ≥30%; the styrene-butadiene copolymer, according to ISO 1133-1:2022 standard, has a melt mass flow rate of 4 to 10 g / 10 min at 200°C and 5 kg, specifically 5 g / 10 min, 6 g / 10 min, 7 g / 10 min, 8 g / 10 min, and 9 g / 10 min.

[0008] The mass content of butadiene in the above-mentioned styrene-butadiene copolymer can be 26%, 27%, 28%, and 29%, respectively. The mass content of butadiene in the styrene-butadiene copolymer can be controlled by adjusting the feed ratio of the polymerizing monomer (butadiene). The mass content of butadiene in the styrene-butadiene copolymer can be determined by the Weenys method. For details, please refer to "Analysis of Bound Butadiene Content in Styrene-Butadiene Copolymer using an Improved Weenys Method" (Synthetic Rubber Industry, 1995, 18(2):113).

[0009] Styrene-butadiene copolymers can be obtained by purchasing or making them in-house, specifically from ASAFLEX 830 (manufacturer: Asahi Kasei), ASAFLEX 825 (manufacturer: Asahi Kasei), KR03 (manufacturer: Styrene-Lyn), KR05 (manufacturer: Styrene-Lyn), etc.

[0010] The styrene-methyl methacrylate copolymer A contains 20% to 30% methyl methacrylate by mass.

[0011] The mass content of methyl methacrylate in styrene-methyl methacrylate copolymer A can be 21%, 23%, 25%, 27%, or 29%, and can be controlled by adjusting the feed ratio of the polymerizing monomer (methyl methacrylate).

[0012] The heat-resistant modifier is at least one of styrene-maleic anhydride copolymer, styrene-acrylate-maleic anhydride copolymer, and styrene-acrylonitrile-maleic anhydride copolymer.

[0013] The heat-resistant modifier is a copolymer of at least one of styrene, acrylate, and acrylonitrile with maleic anhydride. It can be obtained by purchasing or making it in-house. Specifically, it can be prepared by the following method: using at least one of styrene, acrylate, or acrylonitrile as the polymerizing monomer, and copolymerizing it with maleic anhydride under the initiation of dicumyl peroxide (DCP).

[0014] The phase modifier is at least one of polystyrene and styrene-methyl methacrylate copolymer B, wherein the melt flowability of styrene-methyl methacrylate copolymer B is higher than that of styrene-methyl methacrylate copolymer A.

[0015] Polystyrene can be purchased, specifically G-32 (manufacturer: Toyo); the methyl methacrylate content in styrene-methyl methacrylate copolymer B is 10% to 30%, specifically 12%, 15%, 18%, 20%, 23%, 25%, and 28%.

[0016] The haze regulator is at least one of polymethyl methacrylate and styrene-methyl methacrylate copolymer C, wherein the styrene-methyl methacrylate copolymer C contains ≥60% methyl methacrylate by mass.

[0017] Polymethyl methacrylate (PMMA) can be purchased; specifically, it can be CM-207 (manufacturer: Chi Mei).

[0018] The styrene-methyl methacrylate copolymers A, B, or C mentioned above can be obtained by purchasing or self-making, specifically NAS21 (manufacturer: Benlyn) or MS-300 (Nippon Steel Chemicals, Japan); or prepared by the following method: Dicumyl peroxide (DCP), methyl methacrylate, and styrene are mixed at a mass ratio of 0.1:(8-12):(85-95) and then subjected to suspension polymerization in an inert atmosphere. When the suspended particles harden, the temperature of the reaction system is raised to 95-105℃ and maintained for 1.5-2.5 hours to promote the completion of the polymerization reaction. After the reaction is completed, the mixture is washed with water and dried for later use.

[0019] This invention uses a styrene-butadiene copolymer with a specific butadiene content as the base resin, combined with a styrene-methyl methacrylate copolymer with a specific methyl methacrylate content. A specific heat-resistant modifier is used to improve the heat resistance of the composition, and a low-refractive-index haze modifier is incorporated to balance the refractive index of the blend system, thereby achieving high light transmittance (≥85%) and low haze (≤10%). Simultaneously, the rheological properties (high fluidity) of the phase modifier are utilized to promote uniform dispersion of each component and optimize the surface phase distribution of the composition, reducing surface stickiness and adsorption. This results in a styrene-butadiene copolymer composition that simultaneously possesses excellent heat resistance, high transparency, and easy demolding performance (≤625N).

[0020] Optionally, the weight percentages of the styrene-butadiene copolymer in the above-mentioned styrene-butadiene copolymer can be 42 parts, 44 parts, 46 parts, 48 ​​parts, 50 parts, 52 parts, 54 parts, 56 parts, 58 parts, 60 parts, 62 parts, or 64 parts; the weight percentages of the styrene-methyl methacrylate copolymer A can be 10 parts, 15 parts, 20 parts, 25 parts, or 30 parts; the weight percentages of the heat-resistant modifier can be 21 parts, 23 parts, 25 parts, 27 parts, 29 parts, 31 parts, 33 parts, 35 parts, 37 parts, or 39 parts; the weight percentages of the phase modifier can be 6 parts, 7 parts, 8 parts, or 9 parts; and the weight percentages of the haze modifier can be 0.5 parts, 1 part, 1.5 parts, 2 parts, 2.5 parts, 3 parts, 3.5 parts, 4 parts, or 4.5 parts.

[0021] In a preferred embodiment of the styrene-butadiene copolymer composition of the present invention, the mass ratio of the phase modifier to the styrene-butadiene copolymer is 1:(5-10). Optionally, the mass ratio of the phase modifier to the styrene-butadiene copolymer can be 1:5.5, 1:6, 1:6.5, 1:7, 1:7.5, 1:8, 1:8.5, 1:9, or 1:9.5.

[0022] In a preferred embodiment of the styrene-butadiene copolymer composition of the present invention, the mass ratio of the haze modifier to the heat-resistant modifier is 1:(10-60), more preferably 1:(15-30). Optionally, the mass ratio of the haze modifier to the heat-resistant modifier can be 1:15, 1:20, 1:25, 1:30, 1:35, 1:40, 1:45, 1:50, or 1:55.

[0023] In a preferred embodiment of the styrene-butadiene copolymer composition of the present invention, the heat-resistant modifier contains ≥20% maleic anhydride by mass; more preferably, the heat-resistant modifier contains 20% to 30% maleic anhydride by mass. The mass content of maleic anhydride in the above-mentioned heat-resistant modifier can be obtained by adjusting the feed ratio of the polymeric monomer maleic anhydride. The mass content of maleic anhydride in the heat-resistant modifier can be determined by acid-base titration.

[0024] As a preferred embodiment of the styrene-butadiene copolymer composition of the present invention, according to ISO 1133-1:2022 standard, under the conditions of 200°C and 5kg, the difference in melt mass flow rate between the styrene-methyl methacrylate copolymer B and the styrene-methyl methacrylate copolymer A is ≥8g / 10min, preferably 8 to 16g / 10min.

[0025] As a preferred embodiment of the styrene-butadiene copolymer composition of the present invention, according to ISO 1133-1:2022 standard, at 200°C and 5 kg, the melt flow rate of the styrene-methyl methacrylate copolymer A is 2-4 g / 10 min, and the melt flow rate of the styrene-methyl methacrylate copolymer B is ≥12 g / 10 min (preferably 12-18 g / 10 min).

[0026] As a preferred embodiment of the styrene-butadiene copolymer composition of the present invention, the styrene-butadiene copolymer composition further includes 0.2 to 5 parts by weight of processing aids; the processing aids are at least one of antioxidants, weathering agents, and colorants.

[0027] In a preferred embodiment of the styrene-butadiene copolymer composition of the present invention, the antioxidant is at least one selected from hindered phenolic antioxidants, phosphite antioxidants, and thioether antioxidants. Optionally, the hindered phenolic antioxidant may be selected from SONOX 1010, CHINOX 1076, etc., the phosphite antioxidant may be selected from SONOX 168, SONOX 626, etc., and the thioether antioxidant may be selected from RIANOX 412S, etc.

[0028] In a preferred embodiment of the styrene-butadiene copolymer composition of the present invention, the weathering agent is at least one of benzophenone-based ultraviolet absorbers, benzotriazole-based ultraviolet absorbers, and hindered amine-based light stabilizers.

[0029] In a preferred embodiment of the styrene-butadiene copolymer composition of the present invention, the colorant is at least one of pigment colorant, dye colorant, and light diffusing agent.

[0030] Secondly, the present invention provides a method for preparing the above-mentioned styrene-butadiene copolymer composition, comprising the following steps: mixing each component evenly and then melt-extruding to obtain the styrene-butadiene copolymer composition; wherein, specifically, a twin-screw extruder can be used for melt extrusion, the melt extrusion temperature is 160-250°C and the screw speed of the twin-screw extruder is 200-800 rpm.

[0031] Thirdly, the present invention provides the application of the above-mentioned styrene-butadiene copolymer composition in the preparation of transparent containers, panels and other components for household appliances, consumer electronics, automobiles or electronic and electrical products.

[0032] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0033] This invention uses a styrene-butadiene copolymer with a specific butadiene content as the base resin, and combines it with a styrene-methyl methacrylate copolymer with a specific methyl methacrylate content, and combines it with specific heat-resistant modifiers, phase modifiers and haze modifiers, so that the styrene-butadiene copolymer composition has good heat resistance, high transparency and easy demolding performance. Detailed Implementation

[0034] To better illustrate the purpose, technical solution, and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments.

[0035] Unless otherwise specified, all other materials, reagents, etc. used in the examples and comparative examples are commercially available.

[0036] 1. Raw materials and reagents

[0037] 1) Styrene-butadiene copolymer 1 (SB-1): The styrene-butadiene copolymer contains 30% butadiene by mass, is grade ASAFLEX 830, and is manufactured by Asahi Kasei.

[0038] 2) Styrene-butadiene copolymer 2 (SB-2): The styrene-butadiene copolymer contains 25% butadiene by mass, is grade ASAFLEX825, and is manufactured by Asahi Kasei.

[0039] 3) Styrene-butadiene copolymer 3 (SB-3): The styrene-butadiene copolymer contains 15% butadiene by mass, is grade 800S, and is manufactured by Asahi Kasei.

[0040] 4) Styrene-butadiene copolymer 4 (SB-4): The mass content of butadiene in the styrene-butadiene copolymer is 45%, the grade is 687, and the manufacturer is Yingquan Chemical.

[0041] 5) Styrene-methyl methacrylate copolymer 1 (SM-1): The styrene-methyl methacrylate copolymer contains 20% methyl methacrylate by mass, has a melt flow rate of 2.5 g / 10 min, is graded NAS21, and is manufactured by Benlin.

[0042] 6) Styrene-methyl methacrylate copolymer 2 (SM-2): The styrene-methyl methacrylate copolymer contains 30% methyl methacrylate by mass, has a melt mass flow rate of 2.8 g / 10 min, is graded MS-300, and is manufactured by Nippon Steel Chemicals.

[0043] 7) Styrene-methyl methacrylate copolymer 3 (SM-3): The styrene-methyl methacrylate copolymer contains 10% methyl methacrylate by mass and has a melt flow rate of 3.0 g / 10 min;

[0044] The above-mentioned styrene-methyl methacrylate copolymer 3 was prepared by the following method:

[0045] 0.1 parts by weight of dicumyl peroxide (DCP), 10 parts by weight of methyl methacrylate, and 90 parts by weight of styrene were subjected to suspension polymerization under stirring and nitrogen protection. When the suspended particles hardened, the temperature of the reaction system was raised to 100°C and maintained for 2 hours to promote the completion of the polymerization reaction. After the reaction was completed, the mixture was washed with water and dried for later use.

[0046] 8) Heat-resistant modifier 1 (HT-1) is a styrene-maleic anhydride copolymer: the mass content of maleic anhydride in the styrene-maleic anhydride copolymer is 25%, the grade is SMA-725, and the manufacturer is Jiaxing Huawen.

[0047] 9) Heat-resistant modifier 2 (HT-2) is a styrene-methyl methacrylate-maleic anhydride copolymer: the mass content of maleic anhydride in the styrene-methyl methacrylate-maleic anhydride copolymer is 25%;

[0048] The above-mentioned heat-resistant modifier 2 is prepared by the following method:

[0049] S1. Add 0.1 parts by weight of dicumyl peroxide (DCP), 0.1 parts by weight of dodecyl mercaptan, 15 parts by weight of styrene, and 5 parts by weight of methyl methacrylate to a reactor after stirring evenly, and polymerize at 100°C.

[0050] S2. Dissolve 25 parts by weight of maleic anhydride in 45 parts by weight of styrene and 10 parts by weight of methyl methacrylate to form a mixed solution. Then, drop the mixed solution into the reaction vessel in S1 and control the reaction degree until the mixture in the reaction vessel becomes viscous and the reaction is stopped. After washing with water, drying and crushing, the product is obtained.

[0051] 10) Phase modifier 1 (X-1) is polystyrene with a melt mass flow rate of 15 g / 10 min, grade G-32, and manufacturer Nippon Steel Chemical.

[0052] 11) Phase modifier 2 (X-2) is styrene-methyl methacrylate copolymer (SM-4), the styrene-methyl methacrylate copolymer has a methyl methacrylate content of 20% by mass, a melt mass flow rate of 15g / 10min, the brand name is KS-10, and the manufacturer is Nippon Steel Chemicals.

[0053] 12) Haze regulator 1 (W-1) is polymethyl methacrylate, brand name CM-207, manufactured by Chi Mei;

[0054] 13) Haze regulator 2 (W-2) is styrene-methyl methacrylate copolymer (SM-5), in which the mass content of methyl methacrylate is 60%, the melt mass flow rate is 1.5 g / 10 min, the brand name is PM-600, and the manufacturer is Chi Mei.

[0055] The melt flow rates of the above-mentioned styrene-butadiene copolymer, polystyrene, and styrene-methyl methacrylate copolymer were all measured according to ISO 1133-1:2022 standard at 200°C and 5 kg.

[0056] 2. Preparation method of the styrene-butadiene copolymer composition of the present invention

[0057] After the components are mixed evenly according to the formula, they are added to a twin-screw extruder for melt extrusion to obtain a styrene-butadiene copolymer composition. The melt extrusion temperature is 160-250℃, and the screw speed of the twin-screw extruder is 200-800 rpm.

[0058] Table 1 shows the weight parts of each component in the styrene-butadiene copolymer compositions of Examples 1-12.

[0059]

[0060] In Table 1 above, X / SB refers to the mass ratio of phase modifier to styrene-butadiene copolymer, and W / HT refers to the mass ratio of haze modifier to heat-resistant modifier.

[0061] Table 2 shows the weight parts of each component in the styrene-butadiene copolymer compositions of Comparative Examples 1–6.

[0062]

[0063]

[0064] 3. Performance Testing

[0065] (1) Light transmittance and haze: The sample was injection molded to a thickness of 2.0 mm and tested according to ASTM D1003-2013.

[0066] (2) Heat distortion temperature: Tested under a load of 0.45MPa according to ISO 75-2:2013 standard.

[0067] (3) Demolding force: The cavity demolding force test mold was used. The mold was injected at 200℃ and the cooling time was 20s. The demolding force data was measured by the force sensor inside the test mold.

[0068] Table 3. Performance of the styrene-butadiene copolymer compositions in each example and comparative example.

[0069]

[0070]

[0071] According to the data in Table 3, the light transmittance of the styrene-butadiene copolymer compositions in Examples 1 to 12 is above 85%, the haze is below 10%, the heat distortion temperature is 87 to 92°C, and the demolding force is less than or equal to 625N. This indicates that the styrene-butadiene copolymer compositions of the present invention not only have high transparency, but also good heat resistance and excellent demolding performance.

[0072] Based on the data from Comparative Examples 1 and 2, it can be found that when the butadiene content in the styrene-butadiene copolymer is too low, the refractive index does not match the composition, which not only leads to a decrease in the transparency of the styrene-butadiene copolymer composition, but also a significant increase in its haze. When the butadiene content in the styrene-butadiene copolymer is too high, it will not only reduce the transparency of the styrene-butadiene copolymer composition, but also soften the surface of the composition, reduce its heat resistance, and increase the difficulty of demolding.

[0073] The data from Comparative Examples 3 and 4 show that the performance of the styrene-butadiene copolymer composition is not only related to the styrene-butadiene copolymer, but also affected by the styrene-methyl methacrylate copolymer. When the content of methyl methacrylate in the styrene-methyl methacrylate copolymer is too high or too low, it is difficult to effectively improve the transparency, heat resistance and release properties of the styrene-butadiene copolymer composition at the same time.

[0074] Furthermore, according to the data from Comparative Example 5, when styrene-methyl methacrylate copolymer B is used as a phase modifier, the difference in melt flow rate between it and styrene-methyl methacrylate copolymer A is too small, making it difficult for the phase modifier to function effectively. According to the data from Comparative Example 6, when styrene-methyl methacrylate copolymer C is used as a haze modifier, its methyl methacrylate content is too low, failing to regulate haze and significantly reducing the transparency of the styrene-butadiene copolymer composition.

[0075] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A styrene-butadiene copolymer composition, characterized in that, By weight, it includes the following components: 40-65 parts of styrene-butadiene copolymer, 9-34 parts of styrene-methyl methacrylate copolymer A, 20-40 parts of heat-resistant modifier, 5-10 parts of phase modifier, and 0.5-5 parts of haze modifier; The butadiene content in the styrene-butadiene copolymer is 25%~30% by mass; The styrene-methyl methacrylate copolymer A contains 20% to 30% methyl methacrylate by mass. The heat-resistant modifier is at least one of styrene-maleic anhydride copolymer, styrene-acrylate-maleic anhydride copolymer, and styrene-acrylonitrile-maleic anhydride copolymer. The phase modifier is at least one of polystyrene and styrene-methyl methacrylate copolymer B, wherein the melt flowability of styrene-methyl methacrylate copolymer B is higher than that of styrene-methyl methacrylate copolymer A. The haze regulator is at least one of polymethyl methacrylate and styrene-methyl methacrylate copolymer C; the styrene-methyl methacrylate copolymer C contains ≥60% methyl methacrylate by mass. According to ISO 1133-1:2022 standard, at 200℃ and 5kg, the difference in melt mass flow rate between the styrene-methyl methacrylate copolymer B and the styrene-methyl methacrylate copolymer A is ≥8g / 10min.

2. The styrene-butadiene copolymer composition according to claim 1, characterized in that, The mass ratio of the phase modifier to the styrene-butadiene copolymer is 1:(5~10).

3. The styrene-butadiene copolymer composition according to claim 1, characterized in that, The mass ratio of the haze modifier to the heat-resistant modifier is 1:(10~60).

4. The styrene-butadiene copolymer composition according to claim 1, characterized in that, The heat-resistant modifier contains ≥20% maleic anhydride by mass.

5. The styrene-butadiene copolymer composition according to claim 1, characterized in that, According to ISO 1133-1:2022 standard, under the conditions of 200℃ and 5kg, the melt mass flow rate of the styrene-methyl methacrylate copolymer A is 2~4g / 10min, and the melt mass flow rate of the styrene-methyl methacrylate copolymer B is ≥12g / 10min.

6. The styrene-butadiene copolymer composition according to claim 1, characterized in that, The styrene-butadiene copolymer composition further includes 0.2 to 5 parts by weight of processing aids; the processing aids are at least one of antioxidants, weathering agents, and colorants.

7. The styrene-butadiene copolymer composition according to claim 6, characterized in that, At least one of the following must be met: (a) The antioxidant is at least one of hindered phenolic antioxidants, phosphite antioxidants, and thioether antioxidants; (b) The weathering agent is at least one of benzophenone-based ultraviolet absorbers, benzotriazole-based ultraviolet absorbers, and hindered amine light stabilizers; (c) The colorant is at least one of pigment colorant, dye colorant, and light diffusing agent.

8. A method for preparing the styrene-butadiene copolymer composition according to any one of claims 1 to 7, characterized in that, The process includes the following steps: after mixing the components evenly, the mixture is melt-extruded to obtain a styrene-butadiene copolymer composition.

9. The use of the styrene-butadiene copolymer composition according to any one of claims 1 to 7 in the manufacture of automotive or electronic and electrical product parts.

10. The use of the styrene-butadiene copolymer composition according to any one of claims 1 to 7 in the manufacture of components for household appliances.

11. The use of the styrene-butadiene copolymer composition according to any one of claims 1 to 7 in the manufacture of components for consumer electronics products.

Images