A ps composite material and a preparation method thereof

Abstract

The application discloses a PS composite material and a preparation method thereof, and belongs to the technical field of high polymer materials. The PS composite material is prepared by introducing star-shaped and linear styrene-butadiene copolymers and polyethylene wax as functional components in PS resin. The PS composite material can effectively improve the energy absorption effect in the product, relieve the abnormal sound problem of the product, and improve the rigidity of the product, so that the product has higher reliability when applied to an electric appliance shell.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, specifically to a PS composite material and its preparation method. Background Technology

[0002] PS (polystyrene) resin is a common rigid plastic, and is therefore frequently used in the housings of various electrical appliances. However, because it exists in a rigid glassy state at room temperature and has high rigidity between its molecular chains, frictional energy is converted into vibrational energy rather than heat energy when the components of the product rub against each other. This causes alternating static and sliding friction, resulting in high-frequency abnormal noises (such as "squeaking"). On the other hand, the actual rigidity of existing PS resin products is not ideal in use, and they are prone to significant damage under external forces, so their protective effect on electrical appliances still needs improvement. Summary of the Invention

[0003] Based on the deficiencies of existing technologies, the purpose of this invention is to provide a PS composite material. By introducing star-shaped and linear styrene-butadiene copolymer (SBS) and polyethylene wax as functional components into PS resin, it can not only effectively improve the energy absorption effect inside the product and alleviate the problem of abnormal noise, but also improve the rigidity of the product, making it more reliable when used in electrical appliance housings.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A PS composite material comprising the following components in parts by weight: 70-90 parts PS resin, 10-20 parts star-shaped SBS, 3-15 parts linear SBS, and 1-6 parts polyethylene wax; The viscosity of the star-shaped SBS at 23°C is ≥10000 mPa·s; The polyethylene wax has a viscosity ≥1000 mPa·s at 140°C.

[0005] To overcome the problems of high-frequency noise and low rigidity in existing PS resin composite materials used in the manufacture of electrical appliance casings due to the characteristics of PS resin, resulting in poor reliability, this invention incorporates two different configurations of SBS and polyethylene wax as functional components within the PS resin. The viscosity of the star-shaped SBS and polyethylene wax is controlled. The high-viscosity star-shaped SBS, with its numerous cross-linking points and high degree of intermolecular entanglement, acts as a "buffer elastic layer" during friction, effectively absorbing the energy generated. Linear SBS fills the spaces between the PS resin and star-shaped SBS molecules, increasing the overall material density. This, combined with the high-viscosity polyethylene wax penetrating the gaps in the material's molecular chains, further enhances the material's performance. Simultaneously, it achieves uniform internal lubrication of the molecular chains, further reducing local vibrations and sound diffusion caused by friction due to stress within the material, suppressing the relative slippage of molecular chains within the product, and significantly improving the product's self-absorbing sound effect. On the other hand, high-viscosity star-shaped SBS and linear SBS, under the action of polyethylene wax, have high compatibility with PS resin, allowing them to have high dispersibility in the product. Due to their special configurations, they form a three-dimensional network-like structure within the product through mutual entanglement. This structure provides high rigidity support for the product as a whole, and linear SBS and polyethylene wax can effectively enhance the internal bonding force between molecules, avoiding local rigidity loss due to weak bonding force at different phase interfaces. As a result, the rigidity of the product can reach a high level after processing and preparing it into a shell product.

[0006] If the viscosity of star-shaped SBS is insufficient, its buffering effect on the internal friction of the product will be significantly weakened. In addition, during processing, the network structure formed by low-viscosity star-shaped SBS is prone to more intermolecular gaps, resulting in a high frequency of interfacial friction within the product and failing to alleviate abnormal noise. At the same time, the rigidity support provided by the network structure is insufficient, making it difficult to improve the rigidity of the product. If the viscosity of polyethylene wax is low, it is not only difficult to fix and fill the gaps between molecules to improve the compatibility between product components, but it may also exacerbate the separation of the internal interfaces of the product material due to its own migration and excessive lubrication. As a result, the anti-noise performance and rigidity performance of the product cannot meet expectations.

[0007] Preferably, in the PS composite material, the weight parts of PS resin are 70 parts, 75 parts, 80 parts, 85 parts, 90 parts, or any two of these; the weight parts of star-shaped SBS are 10 parts, 12 parts, 15 parts, 18 parts, 20 parts, or any two of these; the weight parts of linear SBS are 3 parts, 5 parts, 8 parts, 10 parts, 12 parts, 15 parts, or any two of these; and the weight parts of polyethylene wax are 1 part, 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, or any two of these.

[0008] More preferably, the PS composite material comprises the following components in parts by weight: 75-85 parts PS resin, 12-19 parts star-shaped SBS, 4-10 parts linear SBS, and 2-5 parts polyethylene wax.

[0009] Preferably, in the PS composite material, the mass percentage of PS resin is ≥60wt%.

[0010] Preferably, in the PS composite material, the total mass percentage of star-shaped SBS (10-20 parts) and linear SBS (≥10wt%) is ≥10wt%.

[0011] Preferably, the PS resin has a melt flow rate of 5~15 g / 10 min at 200°C and 5 kg load, according to ISO 1133-1-2011 Plastics—Determination of melt mass flow rate and melt volume flow rate of thermoplastics.

[0012] More preferably, the PS resin is a PS resin prepared by emulsion polymerization, and more specifically, a general-purpose PS resin (GPPS).

[0013] It should be noted that the selection of PS resins described in this application is not limited to the above-mentioned types. Those skilled in the art can select other types of PS resins in addition to the types mentioned above, depending on the actual application scenario. As long as the expected technical effect can be achieved when combined with the star-shaped SBS and other key components described in this invention, it is acceptable.

[0014] Preferably, the viscosity of the star-shaped SBS at 23°C is 10,000~20,000 mPa·s.

[0015] Preferably, the viscosity of the star-shaped SBS at 23°C is one or any two of the following: 10000 mPa·s, 12000 mPa·s, 14000 mPa·s, 15000 mPa·s, 18000 mPa·s, and 20000 mPa·s.

[0016] Preferably, the melt flow rate of the star-shaped SBS at 230°C and 5 kg is 1~5 g / 10 min.

[0017] Preferably, the butadiene content of the star-shaped SBS is 60-80 wt%.

[0018] Preferably, the viscosity of the linear SBS at 23°C is 1000 mPa·s to 7000 mPa·s.

[0019] Preferably, the viscosity of the linear SBS at 23°C is within the range of one or any two of the following: 1000 mPa·s, 1500 mPa·s, 2000 mPa·s, 2500 mPa·s, 3000 mPa·s, 3500 mPa·s, 4000 mPa·s, 4500 mPa·s, 5000 mPa·s, and 7000 mPa·s.

[0020] Preferably, the linear SBS has a melt flow rate of 10~30 g / min at 230°C and 5 kg.

[0021] Preferably, the butadiene content of the linear SBS is 60-80 wt%.

[0022] It should be noted that the viscosity of the star-shaped SBS and linear SBS described in this application at 23°C can be confirmed with reference to GB / T1632.1-2021 "Determination of Viscosity of Dilute Polymer Solutions Using Capillary Viscometers - Part 1: General Rules" in the following manner: The sample was dissolved in toluene with a mass fraction of 25%. At 23°C, the outflow time of the pure solvent and the outflow time of the solution were measured using an Ubbelohde viscometer (capillary tube inner diameter of 0.5 mm). The relative viscosity n was calculated. Then, the viscosity N of the product at 23°C was calculated using the standard viscosity A of toluene at 23°C according to N=A×n.

[0023] Preferably, the mass ratio of the star-shaped SBS to the linear SBS is 0.6 to 7.

[0024] More preferably, the mass ratio of the star-shaped SBS to the linear SBS is one of or any two of the following: 0.6, 0.8, 1, 1.5, 1.8, 2, 2.5, 3, 3.5, 4, 4.5, 5, 6, 7.

[0025] More preferably, the mass ratio of the star-shaped SBS to the linear SBS is 1.5 to 4.

[0026] As described above, in the product of this invention, star-shaped SBS provides abundant cross-linking sites and forms a basic elastic three-dimensional structural framework, while linear SBS is interspersed and filled in the star-shaped SBS. The two achieve good molecular chain entanglement. When the ratio of the two is preferably within the above range, the compounding effect is better, the buffering and energy absorption of molecular chain friction is better, the sound absorption effect inside the product is better, the interfacial bonding strength inside the molecules is high, and the rigid support provided by the three-dimensional structure formed is better, and the rigidity of the product is also improved.

[0027] Preferably, the viscosity of the polyethylene wax at 140°C is 1000~6000 mPa·s.

[0028] Preferably, the viscosity of the polyethylene wax at 140°C is one or any two of the following: 1000 mPa·s, 1400 mPa·s, 2000 mPa·s, 3000 mPa·s, 4000 mPa·s, 4500 mPa·s, 5000 mPa·s, 5500 mPa·s, and 6000 mPa·s.

[0029] More preferably, the viscosity of the polyethylene wax at 140°C is 2000 mPa·s to 5500 mPa·s.

[0030] As mentioned above, in addition to fully penetrating and filling the gaps between the matrix resin and SBS molecular chains, polyethylene wax in the product also has the functions of compatibility and internal lubrication. When the viscosity of the polyethylene wax is further preferably within the above range, the polyethylene wax can achieve better penetration, filling, compatibility and internal lubrication, resulting in better anti-noise and rigidity performance of the product.

[0031] The viscosity of the polyethylene wax described in this application can be confirmed in the following way: Polyethylene wax was melted at 140°C, and the viscosity of the molten sample was directly tested using a capillary rheometer.

[0032] Preferably, the components of the PVC composition may also include, but are not limited to, antioxidants, antistatic agents, flame retardants, and colorants. Based on the processing or actual use needs of those skilled in the art, other types of functional additives may be added without affecting the expected performance of the product. For example, the above-mentioned additives can improve the product's antioxidant capacity, antistatic capacity, and flame retardancy without affecting the product's characteristic properties. That is, the description of the product's components in the technical solution of this invention is not a limitation on the types of components.

[0033] More preferably, the PS composite material further includes 0.3 to 1 part of antioxidant.

[0034] More preferably, the antioxidant includes at least one of hindered phenolic antioxidants and phosphite antioxidants.

[0035] Another object of the present invention is to provide a method for preparing the PS composite material, comprising the following steps: The components are added to a screw extruder for melt extrusion and granulation to obtain the PS composite material.

[0036] Preferably, the temperature zones of the screw extruder are set as follows: Zone 1 220~230℃, Zone 2 220~230℃, Zone 3 230~240℃, Zone 4 230~240℃, Zone 5 230~240℃, Zone 6 240~260℃, Zone 7 240~260℃, Zone 8 240~260℃, Zone 9 240~260℃, and Zone 10 240~260℃. The screw speed is 350~600 rpm, and the length-to-diameter ratio is (25~50):1.

[0037] Another object of the present invention is to provide the application of the PS composite material in the manufacture of electrical appliance housings.

[0038] Another object of the present invention is to provide an electrical appliance housing comprising the PS composite material described herein.

[0039] The PS composite material described in this invention, based on the synergistic effect of key components and the selection of component viscosity, can not only effectively alleviate the problem of abnormal noise caused by friction in the PS resin matrix, but also has good self-sound absorption effect. At the same time, it also has superior rigidity and strength, making it very suitable for electrical appliance housings that are sensitive to sound and have certain requirements for protective performance.

[0040] The beneficial effects of this invention are that it provides a PS composite material, which, by introducing star-shaped and linear styrene-butadiene copolymers and polyethylene wax as functional components into PS resin, can not only effectively improve the energy absorption effect inside the product and alleviate the problem of abnormal noise, but also improve the rigidity of the product, making it more reliable when used in electrical appliance housings. Detailed Implementation

[0041] To better illustrate the purpose, technical solution, and advantages of this invention, the invention will be further described below with reference to specific embodiments and comparative examples. The purpose of this description is to provide a detailed understanding of the invention, not to limit its scope. All other embodiments obtained by those skilled in the art without inventive effort are within the protection scope of this invention. Unless otherwise specified, the experimental reagents and instruments involved in the implementation of this invention are commonly used reagents and instruments.

[0042] Examples 1-11 Examples of the PS composite material and its preparation method according to the present invention are shown in Table 1.

[0043] The preparation method of the product includes the following steps: The components are mixed evenly, and then placed in a screw extruder for melt extrusion granulation to obtain the PS composite material.

[0044] During melt extrusion of the component, the temperature zones of the screw extruder are set as follows: Zone 1 220℃, Zone 2 230℃, Zone 3 230℃, Zone 4 240℃, Zone 5 240℃, Zone 6 240℃, Zone 7 250℃, Zone 8 250℃, Zone 9 260℃, and Zone 10 260℃. The screw speed is 500 rpm, and the length-to-diameter ratio is 48:1.

[0045] Comparative Examples 1-6 The only difference between each comparative example and the embodiment is the type and ratio of components, as shown in Table 2.

[0046] In the components described in each embodiment and comparative example, The PS resin 1 is GPPS-123P produced by Shanghai SECCO, with a melt flow rate of 9.3 g / 10 min at 200℃ and 5 kg load. The PS resin 2 is Total Petrochemical's GPPS GP1441, with a melt flow rate of 8.6 g / 10 min at 200°C and a 5 kg load. The star-shaped SBS1 is SBS 3412 produced by Li Changrong, with a viscosity of 20000 mPa·s at 23°C; The star-shaped SBS2 is SBS 3741 produced by Li Changrong, with a viscosity of 12000 mPa·s at 23°C; The star-shaped SBS3 is SBS 3414 produced by Lee Chang-yong, with a viscosity of 480 mPa·s at 23°C; The linear SBS1 is SBS 3502 produced by Lee Chang-Yung, with a viscosity of 7000 mPa·s at 23°C; The linear SBS2 is SBS 3520 produced by Lee Chang-Yung, with a viscosity of 1100 mPa·s at 23°C; The polyethylene wax 1 is Honeywell AC 735, with a viscosity of 6000 mPa·s at 140°C; The polyethylene wax 2 is Honeywell AC 392, with a viscosity of 5200 mPa·s at 140°C; The polyethylene wax 3 is Honeywell AC 715, with a viscosity of 4000 mPa·s at 140°C; The polyethylene wax 4 is Honeywell AC 725, with a viscosity of 1400 mPa·s at 140°C; The polyethylene wax 5 is Honeywell AC 3A, with a viscosity of 450 mPa·s at 140°C; The white oil mentioned is No. 15 white oil produced by Guangzhou Binchuang Chemical. The lubricant is ZINC STEARATE (BS-2818), a stearate-based lubricant produced by Zhongshan Huamingtai Technology. The antioxidant is commercially available antioxidant 1010, a hindered phenolic antioxidant.

[0047] Unless otherwise specified, all components and raw materials used in the embodiments and comparative examples of this invention are commercially available, and the same type of components and raw materials are used in each parallel experiment.

[0048] In Table 1, the weight percentage of silicone refers to the weight percentage of silicone in the silicone masterbatch used.

[0049] Table 1 Table 2 Example of effect 1 To verify the performance of the product described in this invention, the following performance tests were conducted on the products of each embodiment and comparative example, with the specific steps as follows: (1) Bending strength test: Each embodiment and comparative example was tested according to standard ISO 178-2019 at a speed of 2 mm / min; (2) Loss factor test: The samples of each embodiment and comparative example were tested according to ISO 6721-1-2011 at a test temperature of 60℃. (3) Decibels test: The products of each embodiment and comparative example were injection molded into test square plates of 60×60×2mm. The square plates were then manually rubbed in opposite directions in a quiet room, and a decibel meter was set up in the quiet room to receive the decibel values. The test results are shown in Tables 3 and 4.

[0050] Table 3 Table 4 As can be seen from Tables 3 and 4, the PS composite material of the present invention is based on the compounding of two different configurations of SBS and polyethylene wax in PS matrix resin as key components, and the viscosity of star-shaped SBS and polyethylene wax is limited. It can not only effectively achieve ideal self-absorbing sound and noise reduction effect, with a loss factor of more than 0.06 and a decibel value as low as 50dB or below, but also, most importantly, the rigidity of the product is also greatly improved, and the bending strength of the product can reach more than 25MPa.

[0051] In contrast, when low-viscosity star-shaped SBS is used as a product component, it cannot effectively form a buffer structure to alleviate internal friction. The product has a low loss factor and a high decibel value, resulting in poor noise reduction and sound absorption. Comparative Example 2 does not use star-shaped SBS, only linear SBS. Obviously, the product also lacks noise reduction and sound absorption performance, and its flexural modulus is low, indicating insufficient reliability. Although Comparative Example 5 introduces SBS, it only uses star-shaped SBS, which also fails to meet the expected standards. The polyethylene wax in Comparative Example 3 has too low viscosity, resulting in a strong migration tendency during use. It cannot effectively fill the gaps in the resin matrix to achieve internal lubrication and compatibility improvement. The loss factor is low, the decibel value is high, and the flexural modulus does not meet the requirements. Comparative Examples 4 and 6 use conventional lubricants such as stearate or commonly used SBS compound additives such as white oil instead of polyethylene wax. Although both are common lubricating components or SBS compound functional components in PS products, stearate and white oil obviously cannot play the same role in the product system described in this invention. The product has severe internal friction and obvious noise.

[0052] As can be seen from Examples 1 and 6-8, the viscosity of polyethylene wax has a certain influence on the internal friction, anti-noise effect, and flexural modulus of the product. When the viscosity of polyethylene wax is further optimized to be 2000 mPa·s to 5000 mPa·s, the overall performance of the product is better. On the other hand, as can be seen from the comparison of Examples 1 and 9-11, when the mass ratio of star-shaped SBS to linear SBS is further optimized to be 1.5 to 4, the performance of the product is better.

[0053] 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 PS composite material, characterized in that, Includes the following components in parts by weight: 70-90 parts PS resin, 10-20 parts star-shaped SBS, 3-15 parts linear SBS, and 1-6 parts polyethylene wax; The star-shaped SBS has a viscosity ≥10000 mPa·s at 23°C; The viscosity of the polyethylene wax at 140°C is ≥1000 mPa·s.

2. The PS composite material as described in claim 1, characterized in that, The melt flow rate of the PS resin at 200℃ and 5kg load is 5~15g / 10min.

3. The PS composite material as described in claim 1, characterized in that, The viscosity of the star-shaped SBS at 23°C is 10,000~20,000 mPa·s.

4. The PS composite material as described in claim 1, characterized in that, The viscosity of the linear SBS at 23°C is 1000~7000 mPa·s.

5. The PS composite material as described in claim 1, characterized in that, The mass ratio of the star-shaped SBS to the linear SBS is 0.6 to 7; preferably, the mass ratio of the star-shaped SBS to the linear SBS is 1.5 to 4.

6. The PS composite material as described in claim 1, characterized in that, The viscosity of the polyethylene wax at 140°C is 1000~6000 mPa·s.

7. The PS composite material as described in claim 1, characterized in that, The PS composite material also includes 0.3 to 1 part antioxidant.

8. A method for preparing the PS composite material according to any one of claims 1 to 7, comprising the following steps: The components are added to a screw extruder for melt extrusion and granulation to obtain the PS composite material.

9. The use of the PS composite material as described in any one of claims 1 to 7 in the manufacture of electrical appliance housings.

10. An electrical appliance casing, characterized in that, Includes the PS composite material as described in any one of claims 1 to 7.

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