Modified styrene-acrylonitrile copolymer, preparation method thereof and blister board

Abstract

The invention provides a modified styrene-acrylonitrile copolymer, a preparation method thereof and a blister board, and belongs to the field of styrene-acrylonitrile copolymers. According to the invention, the styrene-acrylonitrile copolymer with high acrylonitrile content and the styrene-acrylonitrile copolymer with ultra-high molecular weight are mixed, and nitrile groups in acrylonitrile have solvent resistance and have a strong binding effect with other groups; the ultrahigh-molecular-weight styrene-acrylonitrile copolymer is large in molecular weight, high in polymerization degree and stable in property, and the adsorption uniformity of the plate during plastic uptake forming is improved; meanwhile, butadiene in the high rubber powder can improve the molecular toughness of the material, the large-particle-size high rubber powder and the small-particle-size high rubber powder are compounded, under the condition of the same rubber powder amount, the content of butadiene is increased, the impact resistance of the material is improved, meanwhile, stress cracking is reduced, a self-made plastic uptake machine simulates the plastic uptake condition, and the service life of the plastic uptake machine is prolonged. The method is of great significance in observing and improving molding and appearance conditions of plate plastic uptake.

Description

Technical Field

[0001] The present invention relates to the field of styrene-acrylonitrile copolymers, and particularly to a modified styrene-acrylonitrile copolymer, a preparation method thereof, and a thermoformed sheet. Background Art

[0002] The inner liner materials of refrigeration appliances such as refrigerators and freezers are formed by thermoforming sheets. During use, they are corroded by oil stains, which can lead to increased internal stress in the inner liner materials, causing dark streaks or even cracking. Moreover, materials such as refrigerator inner liners and door liners should also have better temperature adaptability during use, resisting low-temperature cracking and remaining unchanged during the cold and hot cycling process. In addition, the refrigerator inner liner is wrapped by a foam insulation layer and will be in direct contact with cyclopentane, LBA, or polyol blowing agents. Therefore, corrosion resistance to blowing agents is particularly important. Styrene-acrylonitrile-butadiene (ABS) resin is a relatively common material used in refrigerators. It has advantages such as light weight, high gloss, and corrosion resistance. However, ordinary ABS resin still cannot meet the requirements of high corrosion resistance, high impact strength, high melt strength, etc. for sheet thermoforming, especially corrosion resistance to blowing agents.

[0003] Acrylonitrile-styrene copolymer (SAN) is a thermoplastic resin prepared by the polymerization of acrylonitrile and styrene. It has characteristics such as colorless transparency, high heat resistance, excellent gloss, chemical resistance, good hardness, rigidity, dimensional stability, and high load-bearing capacity. It is commonly used in scenarios such as household appliances, automobiles, and construction, with a wide range of application fields. To solve various problems of ordinary ABS resin in the field of sheet thermoforming, modifying acrylonitrile-styrene copolymer to obtain a modified product with high solvent resistance, high impact resistance, and high melt strength has become the research focus.

[0004] CN117986762A discloses a SAN / PA6 alloy material, a preparation method thereof, and applications, including 25-58 parts of SAN resin, 24-50 parts of PA6 resin, 10-30 parts of a toughening agent, and 2-5 parts of a compatibilizer. By introducing PA6 into SAN, the solvent resistance of SAN is improved.

[0005] CN117986762A discloses a SAN / PA6 alloy material, comprising the following components in parts by weight: 25-58 parts of SAN resin, 24-50 parts of PA6 resin, 10-30 parts of toughening agent, and 2-5 parts of compatibilizer. By introducing PA6 into SAN, the solvent resistance of SAN is improved. SAN and PA6 have partial compatibility. By adding a compatibilizer and controlling the dosage of the compatibilizer, while improving the compatibility between the two, the solvent resistance is not affected. By using a specific content of high-nitrile SAN, the solvent swelling resistance of the material is improved. By selecting a specific toughening agent, the discoloration of the material is significantly reduced, and the comprehensive performance is excellent. However, the cost price of the material in this technical solution is high, and the gloss of the synthesized material is also poor, which is not conducive to subsequent thermoforming processing and cannot meet the requirements of thermoforming materials.

[0006] There are endless modification methods for acrylonitrile-styrene copolymers, but the conventional modification methods are still not ideal. Cracks or fractures still occur after long-term exposure to solvents. If applied to the field of thermoformed sheets, the service life of the inner linings of refrigerators, freezers, and refrigerator door linings will be greatly reduced; or thermoforming cannot be achieved due to too high melt index and insufficient melt strength.

[0007] In summary, acrylonitrile-styrene copolymers have excellent high-temperature resistance, rigidity, and hardness, etc. However, how to modify them to solve their defects such as poor toughness, low impact resistance, low temperature intolerance, and poor corrosion resistance, and meet the high performance and high requirements in the field of thermoformed sheets, is still an urgent problem to be solved. Summary of the Invention

[0008] Aiming at the above problems, the present invention provides a modified styrene-acrylonitrile copolymer, its preparation method, and a thermoformed sheet. By mixing a styrene-acrylonitrile copolymer with a high acrylonitrile content and a styrene-acrylonitrile copolymer with ultra-high molecular weight, and adding high rubber powder and other additives for modification, the obtained modified styrene-acrylonitrile copolymer has high impact resistance at normal temperature and low temperature, and good corrosion resistance, and can meet the use of materials in corrosive environments.

[0009] The present invention provides a modified styrene-acrylonitrile copolymer, which is prepared by mixing a styrene-acrylonitrile copolymer with a high acrylonitrile content and a ultra-high molecular weight styrene-acrylonitrile copolymer, and then melt-blending with high rubber powder, antioxidant, lubricant and light stabilizer and injection molding; the melt index of the modified styrene-acrylonitrile copolymer under the conditions of 220 °C / 10 kg is 4.0-5.0 g / 10 min, the tensile strength of the modified styrene-acrylonitrile copolymer is 50-55 MPa, the flexural strength is 75-80 MPa, the elongation at break is 30-40%, the Izod notched impact strength at 23 °C is 300-350 J / m, and the Izod notched impact strength at -30 °C is 130-150 J / m; the gloss of the modified styrene-acrylonitrile copolymer at 60° is 93-95; after the modified styrene-acrylonitrile copolymer is corroded by cyclopentane foaming agent, 1-chloro-3,3,3-trifluoropropene foaming agent (LBA), soybean oil, cottonseed oil and 70% alcohol respectively, there is no cracking phenomenon on the surface.

[0010] Further, the components and contents in the modified styrene-acrylonitrile copolymer are as follows: Styrene-acrylonitrile copolymer with high acrylonitrile content: 65-75 parts by weight; Ultra-high molecular weight styrene-acrylonitrile copolymer: 3-5 parts by weight; High rubber powder: 25-27 parts by weight; Antioxidant: 0.3-0.5 parts by weight; Lubricant: 0.3-0.5 parts by weight; Light stabilizer: 0.3-0.5 parts by weight.

[0011] Further, the mass percentage of acrylonitrile in the styrene-acrylonitrile copolymer with high acrylonitrile content is 30-40 wt.%, the molecular weight is 170,000-300,000, the melt flow rate at 220 °C / 10 kg is 8-12 g / 10 min, and the density is 1.06-1.08 g / cm 3 .

[0012] Further, the molecular weight of the ultra-high molecular weight styrene-acrylonitrile copolymer is 1,000,000-1,500,000, and the density is 1.08-1.10 g / cm 3 .

[0013] Further, the high rubber powder is a compound of small particle size high rubber powder and large particle size high rubber powder in a mass ratio of (4-6):21.

[0014] Further, the particle size of the small particle size high rubber powder is 100-180 nm, and the particle size of the large particle size high rubber powder is 320-350 nm.

[0015] Further, the antioxidant is a compound of a primary antioxidant and a secondary antioxidant in a mass ratio of 2:3.

[0016] Further, the primary antioxidant is one or more of pentaerythritol tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, bis(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)hydrazine, N,N'-hexamethylenebis(3,5-di-tert-butyl-4-hydroxyphenylpropionamide), tris(ethylene glycol) bis[3-(3-tert-butyl-5-methyl-4-hydroxyphenyl)propionate], and 4,6-bis(methylthio)o-cresol.

[0017] Further, the secondary antioxidant is one or more of tris(2,4-di-tert-butylphenyl) phosphite (antioxidant 168), bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite (antioxidant 626), bis(2,4-di-cumylphenyl)pentaerythritol diphosphite (antioxidant 686), distearyl thiodipropionate (DSTP), dilauryl thiodipropionate (DLTP), and pentaerythritol tetrakis(3-laurylthiopropionate) (antioxidant 412S).

[0018] Further, the lubricant is one or more of zinc stearate, calcium stearate, barium stearate, pentaerythritol stearate (PETS), oleic acid amide, stearic acid amide, ethylene bisstearamide (EBS), and liquid paraffin.

[0019] Further, the light stabilizer is one or more of an ultraviolet absorber, a quencher, a free radical scavenger, a light screening agent, and a hindered phenol type light stabilizer.

[0020] Further, the ultraviolet absorber includes benzophenones, salicylates, and benzotriazoles.

[0021] Further, the benzophenones are one or more of 2-hydroxy-4-octyloxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2,4-dihydroxybenzophenone, and 2-hydroxy-4-n-octyloxybenzophenone.

[0022] Further, the salicylate is phenyl salicylate.

[0023] Further, the benzotriazoles are one or more of 2-(2'-hydroxy-5'-methylphenyl)benzotriazole and 2-(2'-hydroxy-3',5'-di-tert-phenyl)-5-chlorobenzotriazole.

[0024] Further, the quencher is one or more of nickel dithiocarbamate salts, thiobisphenol types, and phosphonic acid monoester nickel types.

[0025] Furthermore, the radical scavenger is one or more of 2,2-diphenyl-1-picrylhydrazyl (DPPH), p-benzoquinone, and tetramethylbenzoquinone.

[0026] Furthermore, the light shield agent is one or more of carbon black, zinc oxide, and titanium dioxide.

[0027] Furthermore, the hindered phenol light stabilizer is bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate.

[0028] The present invention also provides a method for preparing a modified styrene-acrylonitrile copolymer. Weigh each component according to the content of each component. The preparation method includes the following steps: Step 1: Add a styrene-acrylonitrile copolymer with a high acrylonitrile content, an ultra-high molecular weight styrene-acrylonitrile copolymer, high rubber powder, an antioxidant, a lubricant, and a light stabilizer into a high-speed mixer and stir and blend them to obtain a blended material. Step 2: Add the blended material into a twin-screw extruder for melt blending, extrude and pelletize, and cool it with deionized water at room temperature and then air-dry it naturally to obtain a mixed masterbatch. Step 3: Add the mixed masterbatch into an injection molding machine for injection molding to obtain a modified styrene-acrylonitrile copolymer.

[0029] Furthermore, in Step 1, the mass ratio of the styrene-acrylonitrile copolymer with a high acrylonitrile content, the ultra-high molecular weight styrene-acrylonitrile copolymer, the high rubber powder, the antioxidant, the lubricant, and the light stabilizer is (65 - 75):(3 - 5):(25 - 27):(0.3 - 0.5):(0.3 - 0.5):(0.3 - 0.5).

[0030] Furthermore, in Step 1, the mass percentage of acrylonitrile in the styrene-acrylonitrile copolymer with a high acrylonitrile content is 30 - 40 wt.%, the molecular weight is 170,000 - 300,000, the melt flow rate at 220 °C / 10 kg is 8 - 12 g / 10 min, and the density is 1.06 - 1.08 g / cm 3 .

[0031] Furthermore, in Step 1, the molecular weight of the ultra-high molecular weight styrene-acrylonitrile copolymer is 1,000,000 - 1,500,000, and the density is 1.08 - 1.10 g / cm 3 .

[0032] Furthermore, in Step 1, the high rubber powder is a compound of small particle size high rubber powder and large particle size high rubber powder with a mass ratio of (4 - 6):21.

[0033] Further, the particle size of the small-particle-size high-rubber powder is 100 - 180 nm, and the particle size of the large-particle-size high-rubber powder is 320 - 350 nm.

[0034] Further, in the step 1, the antioxidant is a compound of a primary antioxidant and a secondary antioxidant in a mass ratio of 2:3.

[0035] Further, the primary antioxidant is one or more of pentaerythritol tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], octadecyl 3,5-di-tert-butyl-4-hydroxyphenylpropionate, bis(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)hydrazine, N,N'-hexamethylenebis(3,5-di-tert-butyl-4-hydroxyphenylpropionamide), tris(ethylene glycol) bis[3-(3-tert-butyl-5-methyl-4-hydroxyphenyl)propionate], and 4,6-bis(methylthio)o-cresol.

[0036] Further, the secondary antioxidant is one or more of tris(2,4-di-tert-butylphenyl) phosphite (antioxidant 168), bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite (antioxidant 626), bis(2,4-dicumylphenyl)pentaerythritol diphosphite (antioxidant 686), distearyl thiodipropionate (DSTP), dilauryl thiodipropionate (DLTP), and pentaerythritol tetrakis(3-laurylthiopropionate) (antioxidant 412S).

[0037] Further, in the step 1, the lubricant is one or more of zinc stearate, calcium stearate, barium stearate, pentaerythritol stearate (PETS), oleic acid amide, stearic acid amide, ethylene bisstearamide (EBS), and liquid paraffin.

[0038] Further, in the step 1, the light stabilizer is one or more of an ultraviolet absorber, a quencher, a free radical scavenger, a light screening agent, and a hindered phenol light stabilizer.

[0039] Further, the ultraviolet absorber includes benzophenones, salicylates, and benzotriazoles.

[0040] Further, the benzophenones are one or more of 2-hydroxy-4-octyloxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2,4-dihydroxybenzophenone, and 2-hydroxy-4-n-octyloxybenzophenone.

[0041] Further, the salicylates are phenyl salicylate.

[0042] Further, the benzotriazoles are one or more of 2-(2'-hydroxy-5'-methylphenyl)benzotriazole and 2-(2'-hydroxy-3',5'-diphenyl)-5-chlorobenzotriazole.

[0043] Further, the quencher is one or more of nickel dithiocarbamate, thio-bisphenol type, and nickel phosphite type.

[0044] Further, the radical scavenger is one or more of 2,2-diphenyl-1-picrylhydrazyl (DPPH), p-benzoquinone, and tetramethyl-p-benzoquinone.

[0045] Further, the light shield is one or more of carbon black, zinc oxide, and titanium dioxide.

[0046] Further, the hindered phenol light stabilizer is bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate.

[0047] Further, in step 1, the speed of the stirring and blending is 300-500 r / min, and the time of the stirring and blending is 5-10 min.

[0048] Further, in step 2, the processing temperature of the twin-screw extruder is 200-230 °C, including eleven temperature zones, where the temperature of zone 1 is 200-210 °C, the temperature of zone 2 is 210-220 °C, the temperature of zone 3 is 215-225 °C, the temperature of zone 4 is 215-225 °C, the temperature of zone 5 is 220-230 °C, the temperature of zone 6 is 220-230 °C, the temperature of zone 7 is 220-230 °C, the temperature of zone 8 is 220-230 °C, the temperature of zone 9 is 215-225 °C, the temperature of zone 10 is 215-225 °C, and the temperature of zone 11 is 210-220 °C.

[0049] Further, in step 2, the die head temperature of the twin-screw extruder is 200-210 °C.

[0050] Further, in step 2, the screw rotation speed of the twin-screw extruder is 400-500 r / min.

[0051] Further, in step 2, the vacuum pressure of the twin-screw extruder is -0.09 to -0.07 MPa.

[0052] Further, in step 2, the melt temperature of the twin-screw extruder is 220-240 °C.

[0053] Further, in step 2, the power of the twin-screw extruder is 6-9 kW.

[0054] Further, the length-diameter ratio of the screw of the twin-screw extruder in the step 2 is 48:1.

[0055] Further, the load of the twin-screw extruder in the step 2 is 60-70%.

[0056] Further, the injection molding temperature of the injection molding machine in the step 3 is 190-230 °C, and its processing temperature is divided into five temperature zones. The temperature of the first temperature zone is 190-200 °C, the temperature of the second temperature zone is 200-210 °C, the temperature of the third temperature zone is 210-220 °C, the temperature of the fourth temperature zone is 220-230 °C, and the temperature of the fifth temperature zone is 220-230 °C.

[0057] The present invention also provides a thermoformed sheet, which is prepared by thermoforming the modified styrene-acrylonitrile copolymer with a small thermoforming machine; the glossiness of the thermoformed sheet is 80-85.

[0058] Further, the modified styrene-acrylonitrile copolymer is in a flat plate structure.

[0059] Further, the thermoforming temperature of the small thermoforming machine is 220-230 °C, and the mass of the material accommodated in the small thermoforming machine is 0.1-0.4 kg; the small thermoforming machine includes a heating top plate, a sheet fixing device and a vacuum chamber from top to bottom.

[0060] Further, the heating top plate is in a square structure, and heating wires are installed in the heating top plate to heat the modified styrene-acrylonitrile copolymer. Four support columns are installed at the four corners of the back of the heating top plate, and the height of the support columns is 1-2 cm.

[0061] Further, the sheet fixing device includes a square fixing frame and fixing blocks. Two round holes are symmetrically opened on both sides of the square fixing frame, and small holes are also opened on the fixing blocks. The size of the small holes on the fixing blocks is the same as that of the round holes on the square fixing frame; The square fixing frame, the modified styrene-acrylonitrile copolymer and the fixing blocks are stacked in sequence from bottom to top. The modified styrene-acrylonitrile copolymer is sandwiched between the square fixing frame and the fixing blocks. The round holes on the square fixing frame are aligned with the small holes on the fixing blocks and fixed by bolts; The outer frame size of the square fixing frame of the sheet fixing device is the same as that of the heating top plate, so that the support columns at the four corners of the heating top plate just support the four corners of the square fixing frame.

[0062] Further, the vacuum chamber is of a hollow rectangular structure, with an open structure above the vacuum chamber. The inner frame size of the vacuum chamber is the same as that of the square fixing frame of the sheet fixing device, and is hermetically connected to the square fixing frame of the sheet fixing device. A vacuum valve is installed below the vacuum chamber.

[0063] Further, the thermoforming process of the thermoformed sheet is as follows: Fix the modified styrene-acrylonitrile copolymer in a flat structure between the square fixing frame and the fixing block, and fix the square fixing frame and the fixing block with bolts. Then place the heating top plate above the sheet fixing device, heat the modified styrene-acrylonitrile copolymer through the heating wire in the sheet, and open the vacuum valve on the vacuum chamber to perform thermoforming on the modified styrene-acrylonitrile copolymer. After cooling, the thermoformed sheet is obtained.

[0064] Advantages of the present invention: 1. The present invention uses a mixture of styrene-acrylonitrile copolymer with a high acrylonitrile content and ultra-high molecular weight styrene-acrylonitrile copolymer. Among them, the nitrile group in acrylonitrile has solvent resistance and strong binding effects with other groups. Moreover, the molecular weight of the ultra-high molecular weight styrene-acrylonitrile copolymer is 1 million - 1.5 million, with a large molecular weight, high degree of polymerization, and stable properties, which improves the adsorption uniformity during sheet thermoforming; the high molecular weight styrene-acrylonitrile copolymer is in a powder state and has good dispersibility during processing; 2. The present invention modifies the styrene-acrylonitrile copolymer by adding high rubber powder. The high rubber powder is distributed inside the styrene-acrylonitrile copolymer resin during the mixing and modification process, and toughens according to the crazing principle, improving the impact resistance of the styrene-acrylonitrile copolymer at normal and low temperatures, and at the same time reducing the melt index; more importantly, the butadiene in the high rubber powder can improve the molecular toughness of the material. The present invention uses a compound of large particle size high rubber powder and small particle size high rubber powder, which increases the content of butadiene under the same amount of rubber powder, and can improve the impact resistance of the material while reducing stress cracking; 3. The glossiness of the modified styrene-acrylonitrile copolymer after thermoforming in the present invention can still be maintained at 80 - 85, with good glossiness. At the same time, the small thermoforming machine used in the present invention during thermoforming can ensure the thermoforming of laboratory-grade materials, overcoming the problem that traditional large thermoforming machines require a large amount of materials. If the thermoformed materials do not meet the standards, a large amount of waste will be generated. The small thermoforming machine in the present invention does not require a large amount of materials and can maintain the original properties of the materials during thermoforming, with a wide range of applications. Description of the Drawings

[0065] Figure 1 It is a surface schematic diagram of the thermoformed sheet in Embodiment 1; Figure 2 Structural schematic diagram of the small-sized thermoforming machine described in the present invention; Figure 3 Surface state diagrams of the modified styrene-acrylonitrile copolymer described in Example 1, 2 and Comparative Examples 2, 3, 5 after being corroded by 1-chloro-3,3,3-trifluoropropene blowing agent (LBA); The reference numerals in the figure are respectively: 1, heating top plate; 2, sheet fixing device; 3, vacuum chamber; 21, square fixing frame; 22, fixing block; 31, vacuum valve. Detailed implementation manners

[0066] The following provides a detailed description of the invention in conjunction with the embodiments: The present invention provides a modified styrene-acrylonitrile copolymer, a preparation method thereof and a thermoformed sheet. By mixing a styrene-acrylonitrile copolymer with a high acrylonitrile content and a styrene-acrylonitrile copolymer with ultra-high molecular weight, and then adding high rubber powder and other additives for modification, its impact resistance and corrosion resistance are greatly improved.

[0067] Example 1 This example provides a modified styrene-acrylonitrile copolymer, which is prepared by mixing a styrene-acrylonitrile copolymer with a high acrylonitrile content and a styrene-acrylonitrile copolymer with ultra-high molecular weight, and then melt-blending with high rubber powder, antioxidant, lubricant and light stabilizer and then injection molding; the melt index of the modified styrene-acrylonitrile copolymer under the conditions of 220 °C / 10 kg is 4.2 g / 10 min, the tensile strength of the modified styrene-acrylonitrile copolymer is 50.5 MPa, the flexural strength is 79 MPa, the elongation at break is 35.7%, the Izod notched impact strength at 23 °C is 318 J / m, and the Izod notched impact strength at -30 °C is 134 J / m; the glossiness of the modified styrene-acrylonitrile copolymer at 60° is 94.7; after being corroded by cyclopentane blowing agent, LBA blowing agent, soybean oil, cottonseed oil and 70% alcohol respectively, the surface of the modified styrene-acrylonitrile copolymer has no cracking phenomenon.

[0068] In this example, the styrene-acrylonitrile copolymer with a high acrylonitrile content is 69 parts by weight; The styrene-acrylonitrile copolymer with ultra-high molecular weight is 4 parts by weight; The high rubber powder is 6 parts by weight of small particle size high rubber powder and 21 parts by weight of large particle size high rubber powder; The antioxidant is 0.2 parts by weight of primary antioxidant and 0.3 parts by weight of secondary antioxidant; The lubricant is 0.3 parts by weight; The light stabilizer is 0.3 parts by weight.

[0069] In this embodiment, the mass percentage of acrylonitrile in the styrene-acrylonitrile copolymer with high acrylonitrile content is 36-38 wt.%, the molecular weight is 170,000-300,000, the melt flow rate at 220 °C / 10 kg is 8-12 g / 10 min, and the density is 1.06-1.08 g / cm 3 , and the manufacturer of the styrene-acrylonitrile copolymer with high acrylonitrile content is Formosa Plastics, and the grade is 3400; The molecular weight of the ultra-high molecular weight styrene-acrylonitrile copolymer is 1,000,000-1,500,000, and the density is 1.08 g / cm 3 , and the manufacturer of the high molecular weight styrene-acrylonitrile copolymer is Kumho of South Korea; The particle size of the small particle size high rubber powder is 100-180 nm, and the particle size of the large particle size high rubber powder is 320-350 nm; The main antioxidant is pentaerythritol tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], and the auxiliary antioxidant is tris(2,4-di-tert-butylphenyl) phosphite; The lubricant is pentaerythritol stearate; The light stabilizer is bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate.

[0070] This embodiment also provides a preparation method of a modified styrene-acrylonitrile copolymer. Weigh each component according to the content of each component. The preparation method includes the following steps: Step 1: Add the styrene-acrylonitrile copolymer with high acrylonitrile content, ultra-high molecular weight styrene-acrylonitrile copolymer, high rubber powder, antioxidant, lubricant and light stabilizer into a high-speed mixer, and stir and blend at 500 r / min for 10 min to obtain a blended material; Step 2: Add the blended material into a twin-screw extruder for melt blending, extrude and pelletize, and cool with deionized water at room temperature and then air-dry naturally to obtain a mixed masterbatch; Step 3: Add the mixed masterbatch into an injection molding machine for injection molding to obtain a modified styrene-acrylonitrile copolymer.

[0071] In this embodiment, the processing temperature of the twin-screw extruder is 200-230 °C, including eleven temperature zones. The temperature of zone 1 is 200-210 °C, the temperature of zone 2 is 210-220 °C, the temperature of zone 3 is 215-225 °C, the temperature of zone 4 is 215-225 °C, the temperature of zone 5 is 220-230 °C, the temperature of zone 6 is 220-230 °C, the temperature of zone 7 is 220-230 °C, the temperature of zone 8 is 220-230 °C, the temperature of zone 9 is 215-225 °C, the temperature of zone 10 is 215-225 °C, and the temperature of zone 11 is 210-220 °C; the die head temperature of the twin-screw extruder is 210 °C, the screw speed is 400 r / min, the vacuum pressure is -0.08 MPa, the melt temperature is 235 °C, the power is 6-9 kW, the screw length-diameter ratio is 48:1, and the load is 60-70%; The injection molding temperature of the injection molding machine is 190-230 °C, and its processing temperature is divided into five temperature zones. The temperature of zone 1 is 190 °C, the temperature of zone 2 is 200 °C, the temperature of zone 3 is 220 °C, the temperature of zone 4 is 230 °C, and the temperature of zone 5 is 230 °C.

[0072] This embodiment also provides a kind of the blister sheet. The blister sheet is prepared by blistering the modified styrene-acrylonitrile copolymer through the above-mentioned small blistering machine; the glossiness of the blister sheet is 82.4.

[0073] As Figure 1 It is a surface schematic diagram of the blister sheet in Embodiment 1. It can be seen from the figure that the blister sheet in this embodiment has high glossiness.

[0074] Embodiment 2 This embodiment provides a modified styrene-acrylonitrile copolymer, which is prepared by mixing a styrene-acrylonitrile copolymer with a high acrylonitrile content and a styrene-acrylonitrile copolymer with ultra-high molecular weight, and then melt-blending with high rubber powder, antioxidant, lubricant and light stabilizer and then injection molding; the melt index of the modified styrene-acrylonitrile copolymer under the conditions of 220 °C / 10 kg is 4.3 g / 10 min, the tensile strength of the modified styrene-acrylonitrile copolymer is 50 MPa, the flexural strength is 79.32 MPa, the elongation at break is 34.9%, the Izod notched impact strength at 23 °C is 314 J / m, and the Izod notched impact strength at -30 °C is 134 J / m; the glossiness of the modified styrene-acrylonitrile copolymer at 60° is 94.5; after the modified styrene-acrylonitrile copolymer is corroded by cyclopentane blowing agent, LBA blowing agent, soybean oil, cottonseed oil and 70% alcohol respectively, there is no cracking phenomenon on the surface.

[0075] In this embodiment, the styrene-acrylonitrile copolymer with a high acrylonitrile content is 69 parts by weight; 4 parts by weight of ultra-high molecular weight styrene-acrylonitrile copolymer; 6 parts by weight of small particle size high rubber powder and 21 parts by weight of large particle size high rubber powder; 0.2 parts by weight of primary antioxidant and 0.3 parts by weight of secondary antioxidant; 0.3 parts by weight of lubricant; 0.3 parts by weight of light stabilizer.

[0076] In the styrene-acrylonitrile copolymer with high acrylonitrile content in this embodiment, the mass percentage of acrylonitrile is 36-38 wt.%, the molecular weight is 170,000-300,000, the melt flow rate at 220 °C / 10 kg is 8-12 g / 10 min, and the density is 1.06-1.08 g / cm 3 , the manufacturer of the styrene-acrylonitrile copolymer with high acrylonitrile content is Jilin Petrochemical, and the grade is 1825; The molecular weight of the ultra-high molecular weight styrene-acrylonitrile copolymer is 1,000,000-1,500,000, and the density is 1.08 g / cm 3 , the manufacturer of the high molecular weight styrene-acrylonitrile copolymer is Kumho of South Korea; The particle size of the small particle size high rubber powder is 100-180 nm, and the particle size of the large particle size high rubber powder is 320-350 nm; The primary antioxidant is pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], and the secondary antioxidant is tris(2,4-di-tert-butylphenyl) phosphite; The lubricant is pentaerythritol stearate; The light stabilizer is bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate.

[0077] This embodiment also provides a preparation method of a modified styrene-acrylonitrile copolymer. Weigh each component according to the content of each component. The preparation method includes the following steps: Step 1: Add the styrene-acrylonitrile copolymer with high acrylonitrile content, ultra-high molecular weight styrene-acrylonitrile copolymer, high rubber powder, antioxidant, lubricant and light stabilizer into a high-speed mixer, and stir and blend at 500 r / min for 10 min to obtain a blended material; Step 2: Add the blended material into a twin-screw extruder for melt blending, extrude and pelletize, and cool with deionized water at room temperature and then air dry naturally to obtain a mixed masterbatch; Step 3: Add the mixed masterbatch into an injection molding machine for injection molding to obtain a modified styrene-acrylonitrile copolymer.

[0078] In this embodiment, the processing temperature of the twin-screw extruder is 200 - 230 °C, including eleven temperature zones. The temperature of zone 1 is 200 - 210 °C, the temperature of zone 2 is 210 - 220 °C, the temperature of zone 3 is 215 - 225 °C, the temperature of zone 4 is 215 - 225 °C, the temperature of zone 5 is 220 - 230 °C, the temperature of zone 6 is 220 - 230 °C, the temperature of zone 7 is 220 - 230 °C, the temperature of zone 8 is 220 - 230 °C, the temperature of zone 9 is 215 - 225 °C, the temperature of zone 10 is 215 - 225 °C, and the temperature of zone 11 is 210 - 220 °C; the die head temperature of the twin-screw extruder is 210 °C, the screw speed is 400 r / min, the vacuum pressure is -0.08 MPa, the melt temperature is 235 °C, the power is 6 - 9 kW, the screw length-diameter ratio is 48:1, and the load is 60 - 70%; The injection temperature of the injection molding machine is 190 - 230 °C, and its processing temperature is divided into five temperature zones. The temperature of zone 1 is 190 °C, the temperature of zone 2 is 200 °C, the temperature of zone 3 is 220 °C, the temperature of zone 4 is 230 °C, and the temperature of zone 5 is 230 °C.

[0079] Example 3 This embodiment provides a modified styrene-acrylonitrile copolymer, which is prepared by mixing a styrene-acrylonitrile copolymer with a high acrylonitrile content and a ultra-high molecular weight styrene-acrylonitrile copolymer, and then melt-blending with high rubber powder, antioxidant, lubricant and light stabilizer and injecting. The melt index of the modified styrene-acrylonitrile copolymer at 220 °C / 10 kg is 4.2 g / 10 min. The tensile strength of the modified styrene-acrylonitrile copolymer is 50.2 MPa, the flexural strength is 79 MPa, the elongation at break is 35.4%, the Izod notched impact strength at 23 °C is 316 J / m, and the Izod notched impact strength at -30 °C is 132 J / m; the glossiness of the modified styrene-acrylonitrile copolymer at 60° is 94.7; after being corroded by cyclopentane foaming agent, LBA foaming agent, soybean oil, cottonseed oil and 70% alcohol respectively, the surface of the modified styrene-acrylonitrile copolymer has no cracking phenomenon.

[0080] In this embodiment, the styrene-acrylonitrile copolymer with a high acrylonitrile content is 69 parts by weight; The ultra-high molecular weight styrene-acrylonitrile copolymer is 4 parts by weight; The high rubber powder is 6 parts by weight of small particle size high rubber powder and 21 parts by weight of large particle size high rubber powder; The antioxidant is 0.2 parts by weight of main antioxidant and 0.3 parts by weight of auxiliary antioxidant; The lubricant is 0.3 parts by weight; The light stabilizer is 0.3 parts by weight.

[0081] In this embodiment, the mass percentage of acrylonitrile in the styrene-acrylonitrile copolymer with high acrylonitrile content is 36-38 wt.%, the molecular weight is 170,000-300,000, the melt flow rate at 220 °C / 10 kg is 8-12 g / 10 min, and the density is 1.06-1.08 g / cm 3 , the manufacturer of the styrene-acrylonitrile copolymer with high acrylonitrile content is Formosa Plastics, and the grade is 3400; The molecular weight of the ultra-high molecular weight styrene-acrylonitrile copolymer is 1,000,000-1,500,000, and the density is 1.08 g / cm 3 , the manufacturer of the high molecular weight styrene-acrylonitrile copolymer is Jinchangshu; The particle size of the small particle size high rubber powder is 100-180 nm, and the particle size of the large particle size high rubber powder is 320-350 nm; The main antioxidant is pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], and the auxiliary antioxidant is tris(2,4-di-tert-butylphenyl) phosphite; The lubricant is pentaerythritol stearate; The light stabilizer is bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate.

[0082] This embodiment also provides a preparation method of a modified styrene-acrylonitrile copolymer. Weigh each component according to the content of each component. The preparation method includes the following steps: Step 1: Add the styrene-acrylonitrile copolymer with high acrylonitrile content, ultra-high molecular weight styrene-acrylonitrile copolymer, high rubber powder, antioxidant, lubricant and light stabilizer into a high-speed mixer, and stir and blend at 500 r / min for 10 min to obtain a blended material; Step 2: Add the blended material into a twin-screw extruder for melt blending, extrude and pelletize, and cool with deionized water at room temperature and then air-dry naturally to obtain a mixed masterbatch; Step 3: Add the mixed masterbatch into an injection molding machine for injection molding to obtain a modified styrene-acrylonitrile copolymer.

[0083] In this embodiment, the processing temperature of the twin-screw extruder is 200 - 230 °C, including eleven temperature zones. The temperature of zone 1 is 200 - 210 °C, the temperature of zone 2 is 210 - 220 °C, the temperature of zone 3 is 215 - 225 °C, the temperature of zone 4 is 215 - 225 °C, the temperature of zone 5 is 220 - 230 °C, the temperature of zone 6 is 220 - 230 °C, the temperature of zone 7 is 220 - 230 °C, the temperature of zone 8 is 220 - 230 °C, the temperature of zone 9 is 215 - 225 °C, the temperature of zone 10 is 215 - 225 °C, and the temperature of zone 11 is 210 - 220 °C; the die head temperature of the twin-screw extruder is 210 °C, the screw speed is 400 r / min, the vacuum pressure is -0.08 MPa, the melt temperature is 235 °C, the power is 6 - 9 kW, the screw length-diameter ratio is 48:1, and the load is 60 - 70%; The injection temperature of the injection molding machine is 190 - 230 °C, and its processing temperature is divided into five temperature zones. The temperature of zone 1 is 190 °C, the temperature of zone 2 is 200 °C, the temperature of zone 3 is 220 °C, the temperature of zone 4 is 230 °C, and the temperature of zone 5 is 230 °C.

[0084] Comparative Example 1 This comparative example provides a styrene-acrylonitrile-butadiene copolymer. The melt index of the styrene-acrylonitrile-butadiene copolymer under the conditions of 220 °C / 10 kg is 5.24 g / 10 min. The tensile strength of the styrene-acrylonitrile-butadiene copolymer is 41 MPa, the flexural strength is 73 MPa, the elongation at break is 38%, the Izod notched impact strength at 23 °C is 275 J / m, and the Izod notched impact strength at -30 °C is 117 J / m; the glossiness of the styrene-acrylonitrile-butadiene copolymer before thermoforming at 60° is 94, and the glossiness after thermoforming is 82; after being corroded by soybean oil and cottonseed oil respectively, the surface of the styrene-acrylonitrile-butadiene copolymer has no cracking phenomenon. After being corroded by cyclopentane foaming agent and 70% alcohol, defects appear on the surface. After being corroded by LBA foaming agent, the surface cracks; The manufacturer of the styrene-acrylonitrile-butadiene copolymer is Ineos Styrolution, and the grade is 595CP.

[0085] This comparative example also provides a thermoformed sheet, which is prepared by thermoforming the modified styrene-acrylonitrile copolymer with the above-mentioned small thermoforming machine; the glossiness of the thermoformed sheet is 82.

[0086] Comparative Example 2 This comparative example provides a modified styrene-acrylonitrile copolymer, which is prepared by melt blending a general styrene-acrylonitrile copolymer, high rubber powder, antioxidant, lubricant, and light stabilizer and then injection molding; the melt index of the modified styrene-acrylonitrile copolymer under the conditions of 220 °C / 10 kg is 8.2 g / 10 min, the tensile strength of the modified styrene-acrylonitrile copolymer is 46 MPa, the flexural strength is 80 MPa, the elongation at break is 20%, the Izod notched impact strength at 23 °C is 262 J / m, and the Izod notched impact strength at -30 °C is 110 J / m; the glossiness of the modified styrene-acrylonitrile copolymer at 60° is 93; after the styrene-acrylonitrile-butadiene copolymer is corroded by soybean oil and cottonseed oil respectively, defects appear on the surface, and after being corroded by cyclopentane blowing agent, LBA blowing agent and 70% alcohol, the surface cracks.

[0087] In this comparative example, the general styrene-acrylonitrile copolymer is 75 parts by weight; The high rubber powder is 25 parts by weight of large particle size high rubber powder; The antioxidant is 0.2 parts by weight of main antioxidant and 0.3 parts by weight of auxiliary antioxidant; The lubricant is 0.3 parts by weight; The light stabilizer is 0.3 parts by weight.

[0088] In this comparative example, the manufacturer of the general styrene-acrylonitrile copolymer is Jilin Petrochemical, and the grade is 2437; The particle size of the small particle size high rubber powder is 100-180 nm; The main antioxidant is pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], and the auxiliary antioxidant is tris(2,4-di-tert-butylphenyl) phosphite; The lubricant is pentaerythritol stearate; The light stabilizer is bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate.

[0089] This comparative example also provides a preparation method of the modified styrene-acrylonitrile copolymer. Weigh each component according to the content of each component. The preparation method includes the following steps: Step 1: Add the general styrene-acrylonitrile copolymer, high rubber powder, antioxidant, lubricant, and light stabilizer to a high-speed mixer, stir and blend at 500 r / min for 10 min to obtain a mixed material; Step 2: Add the mixed material to a twin-screw extruder for melt blending, extrude and pelletize, and cool with deionized water at room temperature and then air-dry naturally to obtain a mixed masterbatch; Step 3: Add the mixed masterbatch to an injection molding machine for injection molding to obtain the modified styrene-acrylonitrile copolymer.

[0090] In this comparative example, the processing temperature of the twin-screw extruder is 200 - 230 °C, including eleven temperature zones. Among them, the temperature of the first zone is 200 - 210 °C, the second zone is 210 - 220 °C, the third zone is 215 - 225 °C, the fourth zone is 215 - 225 °C, the fifth zone is 220 - 230 °C, the sixth zone is 220 - 230 °C, the seventh zone is 220 - 230 °C, the eighth zone is 220 - 230 °C, the ninth zone is 215 - 225 °C, the tenth zone is 215 - 225 °C, and the eleventh zone is 210 - 220 °C; the die head temperature of the twin-screw extruder is 210 °C, the screw speed is 400 r / min, the vacuum pressure is -0.08 MPa, the melt temperature is 235 °C, the power is 6 - 9 kW, the screw length-diameter ratio is 48:1, and the load is 60 - 70%; The injection molding temperature of the injection molding machine is 190 - 230 °C, and its processing temperature is divided into five temperature zones. Among them, the temperature of the first zone is 190 °C, the second zone is 200 °C, the third zone is 220 °C, the fourth zone is 230 °C, and the fifth zone is 230 °C.

[0091] Comparative Example 3 This comparative example provides a modified styrene-acrylonitrile copolymer, which is prepared by melt blending a styrene-acrylonitrile copolymer with a high acrylonitrile content, high rubber powder, antioxidant, lubricant, and light stabilizer and then injection molding; the melt index of the modified styrene-acrylonitrile copolymer under the conditions of 220 °C / 10 kg is 5.36 g / 10 min, the tensile strength of the modified styrene-acrylonitrile copolymer is 49.3 MPa, the flexural strength is 82 MPa, the elongation at break is 26%, the Izod notched impact strength at 23 °C is 272 J / m, and the Izod notched impact strength at -30 °C is 122 J / m; the glossiness of the modified styrene-acrylonitrile copolymer at 60° is 93.5; after the styrene-acrylonitrile-butadiene copolymer is corroded by soybean oil and cottonseed oil respectively, the surface remains unchanged, and after being corroded by cyclopentane blowing agent, LBA blowing agent, and 70% alcohol, defects appear on the surface.

[0092] In this comparative example, the styrene-acrylonitrile copolymer with a high acrylonitrile content is 75 parts by weight; The high rubber powder is 25 parts by weight of large particle size high rubber powder; The antioxidant is 0.2 parts by weight of the main antioxidant and 0.3 parts by weight of the auxiliary antioxidant; The lubricant is 0.3 parts by weight; The light stabilizer is 0.3 parts by weight.

[0093] In this comparative example, the mass percentage of acrylonitrile in the styrene-acrylonitrile copolymer with a high acrylonitrile content is 36-38 wt.%, the molecular weight is 170,000-300,000, the melt flow rate at 220 °C / 10 kg is 8-12 g / 10 min, and the density is 1.06-1.08 g / cm 3 , and the styrene-acrylonitrile copolymer with a high acrylonitrile content is Taiflex, with the grade NX3400; The particle size of the small-particle-size high rubber powder is 100-180 nm; The main antioxidant is pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], and the auxiliary antioxidant is tris(2,4-di-tert-butylphenyl) phosphite; The lubricant is pentaerythritol stearate; The light stabilizer is bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate.

[0094] This comparative example also provides a preparation method of a modified styrene-acrylonitrile copolymer. Weigh each component according to the content of each component. The preparation method includes the following steps: Step 1: Add the styrene-acrylonitrile copolymer with a high acrylonitrile content, high rubber powder, antioxidant, lubricant, and light stabilizer into a high-speed mixer, and stir and blend at 500 r / min for 10 min to obtain a blended material; Step 2: Add the blended material into a twin-screw extruder for melt blending, extrude and pelletize, and cool with deionized water at room temperature and then air-dry naturally to obtain a mixed masterbatch; Step 3: Add the mixed masterbatch into an injection molding machine for injection molding to obtain a modified styrene-acrylonitrile copolymer.

[0095] In this comparative example, the processing temperature of the twin-screw extruder is 200-230 °C, including eleven temperature zones. Among them, the temperature of zone 1 is 200-210 °C, the temperature of zone 2 is 210-220 °C, the temperature of zone 3 is 215-225 °C, the temperature of zone 4 is 215-225 °C, the temperature of zone 5 is 220-230 °C, the temperature of zone 6 is 220-230 °C, the temperature of zone 7 is 220-230 °C, the temperature of zone 8 is 220-230 °C, the temperature of zone 9 is 215-225 °C, the temperature of zone 10 is 215-225 °C, and the temperature of zone 11 is 210-220 °C; the die head temperature of the twin-screw extruder is 210 °C, the screw speed is 400 r / min, the vacuum pressure is -0.08 MPa, the melt temperature is 235 °C, the power is 6-9 kW, the screw length-diameter ratio is 48:1, and the load is 60-70%; The injection temperature of the injection molding machine is 190 - 230 °C, and its processing temperature is divided into five temperature zones. The temperature of the first temperature zone is 190 °C, the temperature of the second temperature zone is 200 °C, the temperature of the third temperature zone is 220 °C, the temperature of the fourth temperature zone is 230 °C, and the temperature of the fifth temperature zone is 230 °C.

[0096] Comparative Example 4 This comparative example provides a modified styrene - acrylonitrile copolymer, which is prepared by melt - blending a styrene - acrylonitrile copolymer with a high acrylonitrile content, high - rubber powder, antioxidant, lubricant and light stabilizer and then injection - molding; the melt index of the modified styrene - acrylonitrile copolymer under the conditions of 220 °C / 10 kg is 4.8 g / 10 min, the tensile strength of the modified styrene - acrylonitrile copolymer is 49.8 MPa, the flexural strength is 79.87 MPa, the elongation at break is 29%, the Izod notched impact strength at 23 °C is 296 J / m, and the Izod notched impact strength at - 30 °C is 132 J / m; the glossiness of the modified styrene - acrylonitrile copolymer at 60° is 93.4; after being corroded by cyclopentane blowing agent, LBA blowing agent, soybean oil, cottonseed oil and 70% alcohol respectively, the surface of the modified styrene - acrylonitrile copolymer has no cracking phenomenon.

[0097] In this comparative example, the styrene - acrylonitrile copolymer with a high acrylonitrile content is 73 parts by weight; The high - rubber powder is 6 parts by weight of small - particle - size high - rubber powder and 21 parts by weight of large - particle - size high - rubber powder; The antioxidant is 0.2 parts by weight of primary antioxidant and 0.3 parts by weight of secondary antioxidant; The lubricant is 0.3 parts by weight; The light stabilizer is 0.3 parts by weight.

[0098] In this comparative example, the mass percentage of acrylonitrile in the styrene - acrylonitrile copolymer with a high acrylonitrile content is 36 - 38 wt.%, the molecular weight is 170,000 - 300,000, the melt flow rate at 220 °C / 10 kg is 8 - 12 g / 10 min, and the density is 1.06 - 1.08 g / cm 3 , and the styrene - acrylonitrile copolymer with a high acrylonitrile content is from Formosa Plastics, with the grade of NX3400; The particle size of the small - particle - size high - rubber powder is 100 - 180 nm, and the particle size of the large - particle - size high - rubber powder is 320 - 350 nm; The primary antioxidant is pentaerythritol tetrakis [β - (3,5 - di - tert - butyl - 4 - hydroxyphenyl) propionate], and the secondary antioxidant is tris(2,4 - di - tert - butylphenyl) phosphite; The lubricant is pentaerythritol stearate; The light stabilizer is bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate.

[0099] This comparative example also provides a method for preparing a modified styrene-acrylonitrile copolymer. Weigh each component according to the content of each component. The preparation method includes the following steps: Step 1: Add a styrene-acrylonitrile copolymer with a high acrylonitrile content, high rubber powder, antioxidant, lubricant, and light stabilizer to a high-speed mixer, and stir for 10 minutes at 500 r / min for blending to obtain a blended material. Step 2: Add the blended material to a twin-screw extruder for melt blending, extrude and pelletize, and cool with deionized water at room temperature and then air-dry naturally to obtain a mixed masterbatch. Step 3: Add the mixed masterbatch to an injection molding machine for injection molding to obtain a modified styrene-acrylonitrile copolymer.

[0100] In this comparative example, the processing temperature of the twin-screw extruder is 200 - 230 °C, which includes eleven temperature zones. Among them, the temperature of zone 1 is 200 - 210 °C, the temperature of zone 2 is 210 - 220 °C, the temperature of zone 3 is 215 - 225 °C, the temperature of zone 4 is 215 - 225 °C, the temperature of zone 5 is 220 - 230 °C, the temperature of zone 6 is 220 - 230 °C, the temperature of zone 7 is 220 - 230 °C, the temperature of zone 8 is 220 - 230 °C, the temperature of zone 9 is 215 - 225 °C, the temperature of zone 10 is 215 - 225 °C, and the temperature of zone 11 is 210 - 220 °C; the die head temperature of the twin-screw extruder is 210 °C, the screw speed is 400 r / min, the vacuum pressure is -0.08 MPa, the melt temperature is 235 °C, the power is 6 - 9 kW, the screw length-diameter ratio is 48:1, and the load is 60 - 70%; The injection molding temperature of the injection molding machine is 190 - 230 °C, and its processing temperature is divided into five temperature zones. Among them, the temperature of zone 1 is 190 °C, the temperature of zone 2 is 200 °C, the temperature of zone 3 is 220 °C, the temperature of zone 4 is 230 °C, and the temperature of zone 5 is 230 °C.

[0101] This comparative example also provides a thermoformed sheet. The thermoformed sheet is prepared by thermoforming the modified styrene-acrylonitrile copolymer through the above-mentioned small thermoforming machine; the glossiness of the thermoformed sheet is 81.6.

[0102] Comparative Example 5 This comparative example provides a modified styrene-acrylonitrile copolymer, which is prepared by mixing a styrene-acrylonitrile copolymer with a high acrylonitrile content and a ultra-high molecular weight styrene-acrylonitrile copolymer, and then melt-blending with high rubber powder, antioxidant, lubricant and light stabilizer and injection molding; the melt index of the modified styrene-acrylonitrile copolymer under the conditions of 220 °C / 10 kg is 4.0 g / 10 min, the tensile strength of the modified styrene-acrylonitrile copolymer is 51 MPa, the flexural strength is 77.1 MPa, the elongation at break is 36%, the Izod notched impact strength at 23 °C is 325 J / m, and the Izod notched impact strength at -30 °C is 140 J / m; the gloss of the modified styrene-acrylonitrile copolymer at 60° is 94; after the styrene-acrylonitrile-butadiene copolymer is corroded by cyclopentane foaming agent, soybean oil and cottonseed oil respectively, defects appear on the surface, and after being corroded by LBA foaming agent and 70% alcohol, the surface cracks.

[0103] In this comparative example, the styrene-acrylonitrile copolymer with a high acrylonitrile content is 67 parts by weight; The ultra-high molecular weight styrene-acrylonitrile copolymer is 4 parts by weight; The high rubber powder is 6 parts by weight of small particle size high rubber powder and 23 parts by weight of large particle size high rubber powder; The antioxidant is 0.2 parts by weight of main antioxidant and 0.3 parts by weight of auxiliary antioxidant; The lubricant is 0.3 parts by weight; The light stabilizer is 0.3 parts by weight.

[0104] In this comparative example, the mass percentage of acrylonitrile in the styrene-acrylonitrile copolymer with a high acrylonitrile content is 36-38 wt.%, the molecular weight is 170,000-300,000, the melt flow rate at 220 °C / 10 kg is 8-12 g / 10 min, and the density is 1.06-1.08 g / cm 3 , the manufacturer of the styrene-acrylonitrile copolymer with a high acrylonitrile content is Formosa Plastics, and the grade is NX3400; The molecular weight of the ultra-high molecular weight styrene-acrylonitrile copolymer is 1,000,000-1,500,000, and the density is 1.08 g / cm 3 , the manufacturer of the high molecular weight styrene-acrylonitrile copolymer is Kumho of South Korea; The particle size of the small particle size high rubber powder is 100-180 nm, and the particle size of the large particle size high rubber powder is 320-350 nm; The main antioxidant is pentaerythritol tetrakis [β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate], and the auxiliary antioxidant is tris (2,4-di-tert-butylphenyl) phosphite; The lubricant is pentaerythritol stearate; The light stabilizer is bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate.

[0105] This comparative example also provides a method for preparing a modified styrene-acrylonitrile copolymer. Weigh each component according to the content of each component. The preparation method includes the following steps: Step 1: Add a styrene-acrylonitrile copolymer with a high acrylonitrile content, an ultra-high molecular weight styrene-acrylonitrile copolymer, high rubber powder, an antioxidant, a lubricant, and a light stabilizer into a high-speed mixer, and stir for 10 minutes at 500 r / min for blending to obtain a blended material; Step 2: Add the blended material into a twin-screw extruder for melt blending, extrude and pelletize, and cool with deionized water at room temperature and then air dry naturally to obtain a mixed masterbatch; Step 3: Add the mixed masterbatch into an injection molding machine for injection molding to obtain a modified styrene-acrylonitrile copolymer.

[0106] In this comparative example, the processing temperature of the twin-screw extruder is 200 - 230 °C, including eleven temperature zones. Among them, the temperature of zone 1 is 200 - 210 °C, the temperature of zone 2 is 210 - 220 °C, the temperature of zone 3 is 215 - 225 °C, the temperature of zone 4 is 215 - 225 °C, the temperature of zone 5 is 220 - 230 °C, the temperature of zone 6 is 220 - 230 °C, the temperature of zone 7 is 220 - 230 °C, the temperature of zone 8 is 220 - 230 °C, the temperature of zone 9 is 215 - 225 °C, the temperature of zone 10 is 215 - 225 °C, and the temperature of zone 11 is 210 - 220 °C; the die head temperature of the twin-screw extruder is 210 °C, the screw speed is 400 r / min, the vacuum pressure is -0.08 MPa, the melt temperature is 235 °C, the power is 6 - 9 kW, the screw length-diameter ratio is 48:1, and the load is 60 - 70%; The injection molding temperature of the injection molding machine is 190 - 230 °C, and its processing temperature is divided into five temperature zones. Among them, the temperature of the first temperature zone is 190 °C, the temperature of the second temperature zone is 200 °C, the temperature of the third temperature zone is 220 °C, the temperature of the fourth temperature zone is 230 °C, and the temperature of the fifth temperature zone is 230 °C.

[0107] As Figure 3 This is the surface state diagram of the modified styrene-acrylonitrile copolymer in Examples 1 and 2 and Comparative Examples 2, 3, and 5 after being corroded by 1-chloro-3,3,3-trifluoropropene blowing agent (LBA). As shown in the figure, the modified styrene-acrylonitrile copolymer in Comparative Example 2 breaks after being corroded by the blowing agent, while cracks appear on the surface of Comparative Examples 3 and 5 after being corroded by the blowing agent.

[0108] In Example 1, Comparative Examples 1 and 4 of the present invention, the size of the thermoformed sheet is 200*200 mm; the thermoforming temperature of the small thermoforming machine is 220-230 °C, and the mass of the material accommodated in the small thermoforming machine is 0.1-0.4 kg; the small thermoforming machine is as described in the above structure, and includes a heating top plate 1, a sheet fixing device 2 and a vacuum chamber 3 from top to bottom.

[0109] Table 1 shows the components and contents in Examples 1-3 and Comparative Examples 2-5

[0110] Table 2 shows the properties of the materials in Examples 1-3 and Comparative Examples 1-5 of the present example

[0111] Table 3 shows the properties of the materials in Examples 1-3 and Comparative Examples 1-5 of the present example for resistance to foaming agent cracking

[0112] Table 4 shows the properties of the materials in Examples 1-3 and Comparative Examples 1-5 of the present example for resistance to solvent cracking

[0113] Table 5 shows the properties of the thermoformed sheets in Example 1 and Comparative Examples 1 and 4 of the present example

[0114] As can be seen from the performance comparison of the materials in Tables 1-5, the materials in the present invention are jointly mixed with styrene-acrylonitrile copolymer with high acrylonitrile content and ultra-high molecular weight styrene-acrylonitrile copolymer, adding high rubber powder with different particle sizes, and other additives, jointly improving the mechanical properties and impact strength under low temperature conditions of the materials, and can meet the requirements of high elongation at break, impact strength and low melt index during thermoforming, to ensure the melt strength of the materials, so as not to break during thermoforming. At the same time, after thermoforming with the specific thermoforming machine in the present invention, excellent gloss and uniformity can still be maintained; In Comparative Example 1, the mechanical properties of the simple styrene-acrylonitrile-butadiene copolymer (ABS) material are low, and the solvent resistance is poor, with defects or cracking occurring under cyclopentane and 70% alcohol conditions; In Comparative Example 2, general styrene-acrylonitrile copolymer is used for modification. Due to the low acrylonitrile content of the general styrene-acrylonitrile copolymer, the intermolecular binding force is insufficient during modification, resulting in a high melt index and a low elongation at break of the modified product, unable to meet the high melt strength required for thermoforming, and the impact strength is low, and cracking will occur under the action of foaming agent and solvent; In Comparative Example 3, only the styrene-acrylonitrile copolymer with a high acrylonitrile content was used for modification, and only a single large-particle-size high rubber powder was used. The butadiene content was relatively low, resulting in relatively low impact strength at low and normal temperatures, and defects still occurred under the test conditions of the blowing agent and alcohol. In Comparative Example 4, only the styrene-acrylonitrile copolymer with a high acrylonitrile content was used for modification. The impact strength was slightly lower, the performance of resistance to blowing agent and solvent was qualified, but the blister forming uniformity was not good and the glossiness was slightly lower. In Comparative Example 5, the total content of the high rubber powder was too high, and the internal stress of the material was large, so that the material would crack in the presence of the blowing agent and solvent.

[0115] In the present invention, the performance test process of the modified styrene-acrylonitrile copolymer for resistance to cyclopentane or LBA blowing agent, and resistance to soybean oil, cottonseed oil and 70% alcohol is as follows: Place the spline (3.2 mm thick, 13 mm wide) of the modified styrene-acrylonitrile copolymer after injection molding on a special fixture, keep the spline at a 1% strain, place a gauze on the surface of the spline, and drop an equal amount of cyclopentane and blowing agent LBA. The experimental device is in an environment of -30°C (the experiments of resistance to soybean oil, cottonseed oil and 70% alcohol are placed in a normal temperature environment of 25°C). After 48 hours, observe the crack situation on the surface of the experimental spline.

[0116] From the above, it can be seen that the modified styrene-acrylonitrile copolymer in the present invention has made a major breakthrough in high impact resistance, resistance to blowing agent and chemical reagents, which has important significance for the application of styrene-based blister sheets in the refrigerator field. It can also be applied to household appliances, automobiles, buildings, etc. that are in contact with solvents. The cost is relatively low and it has extremely high market prospects.

[0117] The above is only a preferred embodiment of the present invention, and it is not a limitation to the present invention in any other form. Any modification or equivalent change made according to the technical essence of the present invention still belongs to the scope protected by the present invention.

Claims

1. A modified styrene-acrylonitrile copolymer, characterized in that, The modified styrene-acrylonitrile copolymer is prepared by mixing a styrene-acrylonitrile copolymer with a high acrylonitrile content and a ultra-high molecular weight styrene-acrylonitrile copolymer, and then melt-blending with high rubber powder, antioxidant, lubricant and light stabilizer followed by injection molding; the melt index of the modified styrene-acrylonitrile copolymer under the condition of 220 °C / 10 kg is 4.0 - 5.0 g / 10 min, the tensile strength of the modified styrene-acrylonitrile copolymer is 50 - 55 MPa, the flexural strength is 75 - 80 MPa, the elongation at break is 30 - 40%, the Izod notched impact strength at 23 °C is 300 - 350 J / m, and the Izod notched impact strength at -30 °C is 130 - 150 J / m; the glossiness of the modified styrene-acrylonitrile copolymer at an angle of 60° is 93 - 95; after being corroded by cyclopentane foaming agent, 1-chloro-3,3,3-trifluoropropene foaming agent, soybean oil, cottonseed oil and 70% alcohol respectively, the surface of the modified styrene-acrylonitrile copolymer has no cracking phenomenon.

2. The modified styrene-acrylonitrile copolymer according to claim 1, wherein The components and contents in the modified styrene-acrylonitrile copolymer are as follows: Styrene-acrylonitrile copolymer with a high acrylonitrile content: 65 - 75 parts by weight; Ultra-high molecular weight styrene-acrylonitrile copolymer: 3 - 5 parts by weight; High rubber powder: 25 - 27 parts by weight; Antioxidant: 0.3 - 0.5 parts by weight; Lubricant: 0.3 - 0.5 parts by weight; Light stabilizer: 0.3 - 0.5 parts by weight.

3. The modified styrene-acrylonitrile copolymer according to claim 1, characterized in that, The mass percentage of acrylonitrile in the styrene-acrylonitrile copolymer with a high acrylonitrile content is 30-40 wt.%, the molecular weight is 170,000-300,000, the melt flow rate at 220 °C / 10 kg is 8-12 g / 10 min, and the density is 1.06-1.08 g / cm 3 .

4. The modified styrene-acrylonitrile copolymer according to claim 1, wherein The molecular weight of the ultra-high molecular weight styrene-acrylonitrile copolymer is 1 million to 1.5 million, and the density is 1.08-1.10 g / cm 3 .

5. The modified styrene-acrylonitrile copolymer according to claim 1, wherein The high rubber powder is a compound of small particle size high rubber powder and large particle size high rubber powder with a mass ratio of (4 - 6):

21.

6. The modified styrene-acrylonitrile copolymer according to claim 5, wherein The particle size of the small particle size high rubber powder is 100 - 180 nm, and the particle size of the large particle size high rubber powder is 320 - 350 nm.

7. A method for preparing the modified styrene-acrylonitrile copolymer according to any one of claims 1-6, characterized in that, Weigh each component according to the content of each component, and the preparation method includes the following steps: Step 1: Add the styrene-acrylonitrile copolymer with a high acrylonitrile content, ultra-high molecular weight styrene-acrylonitrile copolymer, high rubber powder, antioxidant, lubricant and light stabilizer into a high-speed mixer and stir and blend to obtain a blended material; Step 2: Add the blended material into a twin-screw extruder for melt blending, extrude and pelletize, and cool with deionized water at room temperature and then air dry naturally to obtain a mixed masterbatch; Step 3: Add the mixed masterbatch into an injection molding machine for injection molding to obtain the modified styrene-acrylonitrile copolymer.

8. The preparation method according to claim 7, characterized in that, In Step 2, the processing temperature of the twin-screw extruder is 200 - 230 °C, including eleven temperature zones, where the temperature of Zone 1 is 200 - 210 °C, the temperature of Zone 2 is 210 - 220 °C, the temperature of Zone 3 is 215 - 225 °C, the temperature of Zone 4 is 215 - 225 °C, the temperature of Zone 5 is 220 - 230 °C, the temperature of Zone 6 is 220 - 230 °C, the temperature of Zone 7 is 220 - 230 °C, the temperature of Zone 8 is 220 - 230 °C, the temperature of Zone 9 is 215 - 225 °C, the temperature of Zone 10 is 215 - 225 °C, and the temperature of Zone 11 is 210 - 220 °C.

9. The blister sheet, characterized in that, The thermoformed sheet is prepared by thermoforming the modified styrene-acrylonitrile copolymer according to any one of claims 1 - 6 with a small thermoforming machine; the glossiness of the thermoformed sheet is 80 - 85.

10. The plastic suction sheet according to claim 9, characterized in that, The thermoforming temperature of the small thermoforming machine is 220 - 230 °C, and the mass of the material accommodated in the small thermoforming machine is 0.1 - 0.4 kg; the small thermoforming machine includes a heating top plate (1), a sheet fixing device (2), and a vacuum chamber (3) from top to bottom respectively.

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