Preparation method of a transparent high-temperature resistant PVC crystal board

Abstract

The present invention discloses a method for preparing a transparent, high-temperature resistant PVC crystal plate, and relates to the field of plastic processing technology. The present invention adds N-phenylmaleimide cross-linking agent during emulsion polymerization of acrylate and 2-phenyl-1,3-butadiene monomer, and this cross-linking agent can improve the heat resistance of the polymer; after obtaining an acrylic elastomer colloid, glycidyl methacrylate and styrene are grafted to form a polymer in a stepwise manner, and the polymer is added into PVC resin as a heat-resistant cross-linking agent to improve its high-temperature resistance, and the light transmittance of the resin is effectively guaranteed; secondly, hydroxy-terminated polydimethylsiloxane is grafted and modified with maleic anhydride and POE resin matrix, and the heat resistance of the POE resin after modified melt granulation is optimized, and then blended with PVC resin to form a dense network structure, to achieve a very excellent heat-resistant effect; in addition, the present invention also ensures that the transparency of the crystal plate is prepared. The crystal plate prepared by the present invention has high-temperature resistant and highly transparent effects.

Description

Technical Field

[0001] The invention relates to the technical field of plastic processing, in particular to a method for preparing a transparent high-temperature resistant PVC crystal plate. Background Art

[0002] Nowadays, a new material, soft glass, is becoming a popular alternative to glass. It's widely used in the workplace, such as electronics, chemicals, pharmaceuticals, food processing, garment factories, work platforms, machine surfaces, and various office desks. In the home, it's widely used on glass surfaces, showcasing the glass's natural color and creating a stylish look while also protecting glass furniture from scratches. Crystal board is actually a transparent soft PVC board, a high-quality plastic composite material with a smooth, bright, transparent surface, free of cracks and bubbles, and a uniform color.

[0003] Polyvinyl chloride resin has been widely used as a general-purpose resin. When used alone, its optical properties are good, but its mechanical and physical properties are not very good, especially in terms of high-temperature strength. In order to improve its high-temperature resistance, it is necessary to add various modifiers to modify the material. The substituted chlorine groups contained in the PVC molecular structure easily lead to the dehydrochlorination reaction of the PVC resin, which causes the degradation reaction of PVC. PVC is extremely unstable to heat. Rising temperature will greatly promote the PVC dehydrochlorination reaction, which can cause harm to the human body using the crystal plate, and also reduce the aesthetics of the crystal plate, resulting in the disadvantage of too short a service life. How to improve the high-temperature resistance of PVC crystal plate while ensuring its transparency is the focus of the research of this invention. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for preparing a transparent high-temperature resistant PVC crystal plate to solve the problems existing in the prior art.

[0005] In order to solve the above technical problems, the present invention provides the following technical solution: a method for preparing a transparent high-temperature resistant PVC crystal plate, comprising the following preparation steps:

[0006] (1) A three-necked flask is continuously filled with inert gas. After the air is expelled, 60 parts of deionized water, 0.16-0.18 parts of emulsifier, and 0.1 parts of potassium persulfate are added, and the mixture is heated and stirred at a stirring speed of 60 rpm and a heating rate of 10°C / min. When the temperature reaches 70°C, a mixed solution of 0.3-0.5 parts of allyl methacrylate and 16-19 parts of 2-phenyl-1,3-butadiene is added dropwise. After the addition is completed, stirring is continued for 1 hour at a stirring speed of 150-250 rpm. A mixed solution of 3-5 parts of N-phenylmaleimide, 0.1 parts of potassium persulfate, and 3-4 parts of deionized water is added dropwise. After the addition is completed, stirring is continued for 1 hour at a stirring speed of 150-250 rpm to obtain an elastomer latex.

[0007] (2) A three-necked flask is continuously filled with inert gas, and 17-19 parts of elastomer latex, 50 parts of deionized water, and 0.1 parts of potassium persulfate are added, and heated to 70°C with a stirring speed of 60 rpm and a heating rate of 10°C / min; then 3.5-4 parts of glycidyl methacrylate are added dropwise for 30 minutes; after the reaction for 1 hour, 3-4 parts of styrene are added dropwise for 30 minutes and maintained for 1 hour; after salting out and condensing with aluminum trichloride solution, the filtrate is filtered and centrifuged for dehydration, washed with deionized water 3 times, and dried at 50°C for 5-8 hours to obtain a powdered polymer heat-resistant crosslinking agent;

[0008] (3) Octamethyltetrasiloxane, hydroxy silicone oil and catalyst were mixed in a weight ratio of 100:0.1-0.2:0.3-0.5, added to a three-necked flask, evacuated to 0.01 MPa at 60°C, then introduced nitrogen, heated to 80-100°C, and reacted for 1-3 hours; heated to 100-120°C, and continued to react for 1-3 hours; then heated to above 160-180°C and evacuated for 0.5-1.5 hours to obtain terminal hydroxyl polydimethylsiloxane; weighed 2-3 parts of maleic anhydride and 0.2-4 parts of terminal hydroxyl polydimethylsiloxane, and added to a beaker. 20 parts of acetone were poured into the mixture to dissolve it, and stirred at 120 rpm until it was completely dissolved; the dissolved mixed solution was then poured into a high-speed mixer containing POE and stirred for 5 minutes at a stirring speed of 400 rpm; finally, the mixed material was injected into a twin-screw extruder, wherein the extruder barrel head temperature was 170-190°C, the main engine speed was 300 r / min, the feed speed was 10 r / min, and the vacuum degree of the vacuum section was 0.05-0.09 MPa; the twin-screw extruder was extruded into filaments, which were then cooled with deionized water and finally dried at room temperature for 24 hours to obtain the modified POE resin;

[0009] (4) 100 parts of PVC resin, 2-3 parts of stabilizer, 8-18 parts of modified POE resin, 50-55 parts of trioctyl trimellitate, and 0.5-0.8 parts of heat-resistant crosslinking agent are accurately weighed according to the formula and placed in a high-speed mixer at a speed of 1250-1450 rpm for mixing. When the temperature rises to 95-105 ° C, the material is discharged into a low-speed mixer at a speed of 70-100 rpm and cooled to 25-35 ° C before discharging; then the material is added to a double-roll open mill for mixing and sheeting, and the roller temperature of the double-roll open mill is 110-120 ° C; finally, the sheet is pressed in a molding machine at 160-180 ° C for 8-10 minutes and then cooled to obtain a transparent high-temperature resistant PVC crystal plate.

[0010] Furthermore, the emulsifier in step (1) is an anionic emulsifier OT.

[0011] Furthermore, the dropwise addition time in step (1) is 1 hour.

[0012] Furthermore, the inert gas in steps (1) and (2) is nitrogen.

[0013] Furthermore, in step (2), the centrifugal speed is 12000-20000 rpm, and the time is 20 min.

[0014] Furthermore, the catalyst in step (3) is tetramethylammonium hydroxide siliconate.

[0015] Furthermore, in step (3), the weight ratio of POE to the mixed solution is 100:0.5-1.5.

[0016] Furthermore, in step (3), the temperature of the high-speed stirrer during stirring is 200-300°C.

[0017] Furthermore, the stabilizer in step (4) is liquid barium zinc.

[0018] Furthermore, the mixing time in step (4) is 300-500s.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] The present invention blends modified POE resin with PVC and adds a homemade heat-resistant cross-linking agent to achieve high temperature resistance and high transparency.

[0021] First, during the emulsion polymerization of acrylic ester and 2-phenyl-1,3-butadiene monomer, an N-phenylmaleimide crosslinker is added to ensure the optical properties of the crystal plate and improve its high-temperature resistance. This crosslinker has a five-membered cyclic monomer with a 1,2-disubstituted vinyl structure. Embedding it in the polymer chain can increase the block's internal rotation resistance, thereby improving the polymer's heat resistance. In this process, a styrene-acrylate binary copolymer is prepared by soap-free emulsion polymerization. Due to the block crosslinking characteristics, this copolymer avoids the defects of conventional modified copolymers containing a large number of unsaturated carbon-carbon double bonds in the molecular chain of the added elastomer component, which leads to poor weather resistance and easy aging after long-term use, thereby reducing the high-temperature resistance of the crystal plate. After obtaining the acrylic elastomer colloid, glycidyl methacrylate is then grafted onto styrene in a step-by-step manner to form a polymer. This copolymer is then added to the PVC resin as a heat-resistant crosslinker to improve its high-temperature resistance. During the polymerization of ethylene, glycidyl methacrylate positions the epoxy group on the side chain, forming an O-type polymer, which effectively ensures the light transmittance of the resin.

[0022] Secondly, octamethyltetrasiloxane is subjected to ring-opening polymerization in an alkaline environment to obtain terminal hydroxyl polydimethylsiloxane, which is then grafted onto a POE resin matrix via maleic anhydride. The heat resistance of the modified melt-granulated POE resin is optimized, and the POE resin is then blended with PVC resin. The soft chain curl structure of octene and the crystalline ethylene chains serve as physical crosslinking points. The two modified resins can form a dense network structure after blending, thereby achieving excellent heat resistance. In addition, the strictly selected POE resin and the addition of various modifiers in the present invention also ensure the transparency of the prepared crystal plate, improving the high-temperature resistance without affecting its transmittance. DETAILED DESCRIPTION

[0023] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0024] In order to more clearly illustrate the method provided by the present invention, the following examples are used to describe in detail the various index testing methods of a transparent high-temperature resistant PVC crystal plate prepared in the following examples.

[0025] Transparency: The samples of the embodiment and the comparative example were made into crystal plates with a thickness of 1 cm, and the light transmittance test was conducted according to the standard GB / T2410-2008.

[0026] High temperature resistance: The samples of the examples and comparative examples were made into crystal plates with a thickness of 1 cm and tested according to the Congo red method described in GB / T 2917.1-2002 at a test temperature of 180°C.

[0027] Example 1; (1) A three-necked flask is continuously filled with nitrogen. After the air is expelled, 60 parts of deionized water, 0.16 parts of anionic emulsifier OT, and 0.1 parts of potassium persulfate are added, and the mixture is heated and stirred at a stirring speed of 60 rpm and a heating rate of 10°C / min; when the temperature is raised to 70°C, a mixed solution of 0.3 parts of allyl methacrylate and 16 parts of 2-phenyl-1,3-butadiene is added dropwise, and the addition time is 1 hour. After the addition is completed, the mixture is stirred for 1 hour at a stirring speed of 150 rpm; a mixed solution of 3 parts of N-phenylmaleimide, 0.1 parts of potassium persulfate, and 3 parts of deionized water is added dropwise, and the addition time is 1 hour. After the addition is completed, the mixture is stirred for 1 hour to obtain an elastomer latex at a stirring speed of 150 rpm;

[0028] (2) A three-necked flask was continuously filled with nitrogen, and 17 parts of elastomer latex, 50 parts of deionized water, and 0.1 parts of potassium persulfate were added. The mixture was heated and stirred to 70°C at a stirring speed of 60 rpm and a heating rate of 10°C / min. Then, 3.5 parts of glycidyl methacrylate were added dropwise for 30 minutes. After the reaction lasted for 1 hour, 3 parts of styrene were added dropwise for 30 minutes and maintained for 1 hour. After salting out and condensing with aluminum trichloride solution, the filtrate was filtered and centrifuged at a speed of 12,000 rpm for 20 minutes. The filtrate was washed with deionized water 3 times and dried at 50°C for 5 hours to obtain a powdered polymer heat-resistant crosslinking agent.

[0029] (3) Octamethyltetrasiloxane, hydroxy silicone oil and catalyst tetramethylammonium hydroxide silicon alkoxide were mixed in a weight ratio of 100:0.1:0.3, added to a three-necked flask, evacuated to 0.01 MPa at 60°C, and then nitrogen was introduced. The temperature was raised to 80°C and the reaction was continued for 1 hour; the temperature was raised to 100°C and the reaction was continued for 1 hour; the temperature was raised to above 160°C and the evacuation was continued for 0.5 hour to obtain terminal hydroxyl polydimethylsiloxane; 2 parts of maleic anhydride and 0.2 parts of terminal hydroxyl polydimethylsiloxane were weighed and added to a beaker. 20 parts of acetone were poured into the beaker to dissolve the hydroxyl end-polymer, and the mixture was stirred at a speed of 120 rpm. The dissolved mixed solution was then poured into a high-speed mixer containing POE and stirred for 5 minutes at a temperature of 200°C and a stirring speed of 400 rpm. The weight ratio of POE to the mixed solution was 100:0.5. Finally, the mixed material was injected into a twin-screw extruder, wherein the extruder barrel head temperature was 170°C, the main engine speed was 300 r / min, the feed speed was 10 r / min, and the vacuum degree of the vacuum section was 0.05 MPa. The twin-screw extruder was extruded into filaments, which were then cooled with deionized water and finally dried at room temperature for 24 hours to obtain the modified POE resin.

[0030] (4) 100 parts of PVC resin, 2 parts of stabilizer liquid barium zinc, 8 parts of modified POE resin, 50 parts of trioctyl trimellitate, and 0.5 parts of heat-resistant crosslinking agent were accurately weighed according to the formula, placed in a high-speed mixer and mixed at a speed of 1250 rpm. When the temperature rose to 95 °C, the material was discharged into a low-speed mixer at a speed of 70 rpm and cooled to 25 °C before discharging. The material was then added to a double-roll mill and mixed to form a sheet for 300 s at a roller temperature of 110 °C. Finally, the sheet was pressed in a molding machine at 160 °C for 8 minutes and then cooled to obtain a transparent high-temperature resistant PVC crystal plate.

[0031] Example 2; (1) A three-necked flask was continuously filled with nitrogen. After the air was expelled, 60 parts of deionized water, 0.17 parts of anionic emulsifier OT, and 0.1 parts of potassium persulfate were added, and the mixture was heated and stirred at a stirring speed of 60 rpm and a heating rate of 10°C / min. When the temperature was raised to 70°C, a mixed solution of 0.4 parts of allyl methacrylate and 17.5 parts of 2-phenyl-1,3-butadiene was added dropwise for 1 hour. After the addition was completed, stirring was continued for 1 hour at a stirring speed of 200 rpm. A mixed solution of 4 parts of N-phenylmaleimide, 0.1 parts of potassium persulfate, and 3.5 parts of deionized water was added dropwise for 1 hour. After the addition was completed, stirring was continued for 1 hour to obtain an elastomer latex at a stirring speed of 200 rpm.

[0032] (2) A three-necked flask was continuously filled with nitrogen, and 18 parts of elastomer latex, 50 parts of deionized water, and 0.1 parts of potassium persulfate were added. The mixture was heated and stirred to 70°C at a stirring speed of 60 rpm and a heating rate of 10°C / min. Then, 3.75 parts of glycidyl methacrylate were added dropwise for 30 minutes. After the reaction lasted for 1 hour, 3.5 parts of styrene were added dropwise for 30 minutes and maintained for 1 hour. After salting out and condensing with aluminum chloride solution, the filtrate was filtered and centrifuged at a speed of 16,000 rpm for 20 minutes. The filtrate was washed with deionized water three times and dried at 50°C for 6.5 hours to obtain a powdered polymer heat-resistant crosslinking agent.

[0033] (3) Octamethyltetrasiloxane, hydroxy silicone oil and catalyst tetramethylammonium hydroxide siliconate were mixed in a weight ratio of 100:0.15:0.4, added to a three-necked flask, evacuated to 0.01 MPa at 60°C, then introduced nitrogen, heated to 90°C, and reacted for 1.5 hours; heated to 110°C, and continued to react for 1.5 hours; then heated to above 170°C and evacuated for 1 hour to obtain terminal hydroxyl polydimethylsiloxane; 2.5 parts of maleic anhydride and 2.1 parts of terminal hydroxyl polydimethylsiloxane were weighed, added to a beaker, and 20 parts of acetone were poured in to dissolve them, and 120r pm speed until completely dissolved; then pour the dissolved mixed solution into a high-speed mixer containing POE and stir for 5 minutes, the temperature is 250℃, the stirring speed is 400rpm, and the weight ratio of POE to the mixed solution is 100:1; finally, the mixed material is injected into a twin-screw extruder, wherein the extruder barrel head temperature is 180℃, the main engine speed is 300r / min, the feed speed is 10r / min, and the vacuum degree of the vacuum section is 0.07MPa; the twin-screw extruder is extruded into filaments, then cooled with deionized water, and finally dried at room temperature for 24 hours to obtain the modified POE resin;

[0034] (4) 100 parts of PVC resin, 2.5 parts of stabilizer liquid barium zinc, 13 parts of modified POE resin, 52.5 parts of trioctyl trimellitate, and 0.65 parts of heat-resistant crosslinking agent were accurately weighed according to the formula, placed in a high-speed mixer and mixed at a speed of 1350 rpm. When the temperature rose to 100 ° C, the material was discharged into a low-speed mixer with a speed of 85 rpm and cooled to 30 ° C before discharging; then the material was added to a double-roll mill and mixed to form a sheet for 400 s, and the roller temperature of the double-roll mill was 115 ° C; finally, the sheet was pressed in a molding machine at 170 ° C for 9 minutes and then cooled to obtain a transparent high-temperature resistant PVC crystal plate.

[0035] Example 3; (1) A three-necked flask is continuously filled with nitrogen. After the air is expelled, 60 parts of deionized water, 0.18 parts of anionic emulsifier OT, and 0.1 parts of potassium persulfate are added, and the mixture is heated and stirred at a stirring speed of 60 rpm and a heating rate of 10°C / min; when the temperature is raised to 70°C, a mixed solution of 0.5 parts of allyl methacrylate and 19 parts of 2-phenyl-1,3-butadiene is added dropwise, and the addition time is 1 hour. After the addition is completed, the mixture is stirred for 1 hour at a stirring speed of 250 rpm; a mixed solution of 5 parts of N-phenylmaleimide, 0.1 parts of potassium persulfate, and 4 parts of deionized water is added dropwise, and the addition time is 1 hour. After the addition is completed, the mixture is stirred for 1 hour to obtain an elastomer latex at a stirring speed of 250 rpm;

[0036] (2) A three-necked flask was continuously filled with nitrogen, and 19 parts of elastomer latex, 50 parts of deionized water, and 0.1 parts of potassium persulfate were added. The mixture was heated and stirred to 70°C at a stirring speed of 60 rpm and a heating rate of 10°C / min. Then, 4 parts of glycidyl methacrylate were added dropwise for 30 minutes. After the reaction lasted for 1 hour, 4 parts of styrene were added dropwise for 30 minutes and maintained for 1 hour. After salting out and condensing with aluminum trichloride solution, the filtrate was filtered and centrifuged at a speed of 20,000 rpm for 20 minutes. The filtrate was washed with deionized water 3 times and dried at 50°C for 8 hours to obtain a powdered polymer heat-resistant crosslinking agent.

[0037] (3) Octamethyltetrasiloxane, hydroxy silicone oil and catalyst tetramethylammonium hydroxide silicon alkoxide were mixed in a weight ratio of 100:0.2:0.5, added to a three-necked flask, evacuated to 0.01 MPa at 60°C, then introduced nitrogen, heated to 100°C, and reacted for 3 hours; heated to 120°C, and continued to react for 3 hours; then heated to above 180°C and evacuated for 1.5 hours to obtain terminal hydroxyl polydimethylsiloxane; weighed 3 parts of maleic anhydride and 4 parts of terminal hydroxyl polydimethylsiloxane, added to a beaker, poured 20 parts of acetone to dissolve it, and stirred at a speed of 120 rpm. Stir until completely dissolved; then pour the dissolved mixed solution into a high-speed mixer containing POE and stir for 5 minutes at a temperature of 300°C and a stirring speed of 400 rpm. The weight ratio of POE to the mixed solution is 100:1.5. Finally, inject the mixed material into a twin-screw extruder, wherein the extruder barrel head temperature is 190°C, the main engine speed is 300 r / min, the feed speed is 10 r / min, and the vacuum degree of the vacuum section is 0.09 MPa. The twin-screw extruder is extruded into filaments, which are then cooled with deionized water and finally dried at room temperature for 24 hours to obtain the modified POE resin.

[0038] (4) 100 parts of PVC resin, 3 parts of stabilizer liquid barium zinc, 18 parts of modified POE resin, 55 parts of trioctyl trimellitate, and 0.8 parts of heat-resistant crosslinking agent were accurately weighed according to the formula and placed in a high-speed mixer and mixed at a speed of 1450 rpm. When the temperature rose to 105 °C, the material was discharged into a low-speed mixer with a speed of 100 rpm and cooled to 35 °C before discharging. The material was then added to a double-roll mill and mixed to form a sheet for 500 s at a roller temperature of 120 °C. Finally, the sheet was pressed in a molding machine at 180 °C for 10 minutes and then cooled to obtain a transparent high-temperature resistant PVC crystal plate.

[0039] Comparative Example 1; The difference between Comparative Example 1 and Example 2 lies in the difference in step (1). Step (1) is changed to: nitrogen is continuously filled into the three-necked flask, and after the air is expelled, 60 parts of deionized water, 0.17 parts of anionic emulsifier OT, and 0.1 parts of potassium persulfate are added, and heated with stirring at a stirring speed of 60 rpm and a heating rate of 10°C / min; when the temperature is raised to 70°C, 0.4 parts of allyl methacrylate and 17.5 parts of a mixed solution of 2-phenyl-1,3-butadiene are added dropwise, and the addition time is 1 hour. After the addition is completed, stirring is continued for 1 hour at a stirring speed of 200 rpm to obtain an elastomer latex at a stirring speed of 200 rpm; the remaining steps are the same as in Example 2.

[0040] Comparative Example 2: The difference between Comparative Example 2 and Example 2 is that step (1) is omitted, and step (2) is changed to: nitrogen is continuously filled into a three-necked flask, 50 parts of deionized water and 0.1 parts of potassium persulfate are added, and then 3.75 parts of glycidyl methacrylate are added dropwise for 30 minutes; after reacting for 1 hour, 3.5 parts of styrene are added dropwise for 30 minutes and maintained for 1 hour; after salting out and coagulation with aluminum trichloride solution, the filtrate is filtered and centrifuged for dehydration at a centrifugal speed of 16000 rpm for 20 minutes, washed three times with deionized water, and dried at 50°C for 6.5 hours to obtain a powdered polymer heat-resistant crosslinking agent; the remaining steps are the same as those in Example 2.

[0041] Comparative Example 3; The difference between Comparative Example 3 and Example 2 is that there is no step (2), and step (4) is changed to: 100 parts of PVC resin, 2.5 parts of stabilizer liquid barium zinc, 13 parts of modified POE resin, 52.5 parts of trioctyl trimellitate, and 0.65 parts of elastomer latex are accurately weighed according to the formula, put into a high-speed mixer and mixed at a speed of 1350 rpm. When the temperature rises to 100°C, the material is discharged into a low-speed mixer with a speed of 85 rpm and cooled to 30°C for discharge; then the material is added to a double-roll open mill and mixed to produce a sheet for 400 seconds, and the roller temperature of the double-roll open mill is 115°C; finally, the sheet is pressed in a molding machine at 170°C for 9 minutes and then cooled to obtain a transparent high-temperature resistant PVC crystal plate; the remaining steps are the same as those in Example 2.

[0042] Comparative Example 4; The difference between Comparative Example 4 and Example 2 is that there is no step (3), and step (4) is changed to: 100 parts of PVC resin, 2.5 parts of stabilizer liquid barium zinc, 52.5 parts of trioctyl trimellitate, and 0.65 parts of heat-resistant crosslinking agent, the materials are accurately weighed according to the formula, put into a high-speed mixer and mixed at a speed of 1350 rpm, when the temperature rises to 100°C, discharge the material into a low-speed mixer with a speed of 85 rpm, cool to 30°C and discharge; then add the material to a double-roll open mill and mix to produce a sheet, the time is 400s, and the roller temperature of the double-roll open mill is 115°C; finally, the opened sheet is pressed in a molding machine at 170°C for 9 minutes and then cooled to obtain a transparent high-temperature resistant PVC crystal plate; the remaining steps are the same as Example 2.

[0043] Comparative Example 5; The difference between Comparative Example 5 and Example 2 lies in the difference in step (3). Step (4) is changed to: 100 parts of PVC resin, 2.5 parts of stabilizer liquid barium zinc, 13 parts of POE resin, 52.5 parts of trioctyl trimellitate, and 0.65 parts of heat-resistant crosslinking agent are accurately weighed according to the formula, put into a high-speed mixer and mixed at a speed of 1350 rpm. When the temperature rises to 100°C, the material is discharged into a low-speed mixer with a speed of 85 rpm and cooled to 30°C for discharge; then the material is added to a double-roll open mill and mixed to form a sheet for 400 seconds, and the roller temperature of the double-roll open mill is 115°C; finally, the sheet is pressed in a molding machine at 170°C for 9 minutes and then cooled to obtain a transparent high-temperature resistant PVC crystal plate; the remaining steps are the same as in Example 2.

[0044] Effect Examples

[0045] Table 1 below shows the performance analysis results of a transparent high-temperature resistant PVC crystal plate using Examples 1 to 3 of the present invention and Comparative Examples 1 to 5.

[0046] Table 1

[0047]

[0048] From the comparison of the experimental data of high temperature resistance of the embodiment and the comparative example, it can be found that the present invention adds an N-phenylmaleimide crosslinker during the emulsion polymerization of acrylic ester and 2-phenyl-1,3-butadiene monomer to ensure the optical properties of the crystal plate and improve its high temperature resistance. This crosslinker has a five-membered cyclic monomer with a 1,2-disubstituted vinyl structure. Embedding it into the polymer chain can increase the internal rotation resistance of the block, thereby improving the heat resistance of the polymer; in this process, a soap-free emulsion polymerization method is used to prepare a styrene-acrylate binary copolymer. Due to the block crosslinking characteristics, it avoids the defects of ordinary modified copolymers with added elastomer components containing a large number of unsaturated carbon-carbon double bonds in the molecular chain, which leads to poor weather resistance and easy aging of the crystal plate during long-term use, thereby reducing its high temperature resistance; after obtaining the acrylic elastomer colloid, methacrylate glycidyl is grafted with styrene in steps to form a polymer, and this copolymer is added to the PVC resin as a heat-resistant crosslinking agent to improve its high temperature resistance. Secondly, under alkaline conditions, octamethyltetrasiloxane is subjected to ring-opening polymerization to obtain terminal hydroxyl polydimethylsiloxane, which is then grafted with maleic anhydride and POE resin matrix for modification. The heat resistance of the POE resin after modified melt granulation is optimized and then blended with PVC resin. The soft chain curled structure of octene and the crystalline ethylene chain serve as physical crosslinking points. After blending, the two modified resins can form a dense network structure to achieve excellent heat-resistant effects. From the experimental data comparison of the transparency of the embodiments and comparative examples, it can be found that the glycidyl methacrylate used in the present invention positions the epoxy group on the side chain during ethylene polymerization to form an O-type polymer, which effectively ensures the light transmittance of the resin. In addition, the POE resin and various modifiers strictly selected by the present invention also ensure the transparency of the crystal plate, without affecting its light transmittance while improving high temperature resistance.

[0049] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims, not the foregoing description, and all variations within the meaning and range of equivalents of the claims are intended to be encompassed therein. Any reference in a claim should not be construed as limiting the claim to which it relates.

Claims

1. A method for preparing a transparent high-temperature resistant PVC crystal plate, characterized in that: The method comprises the following preparation steps: (1) A three-necked flask is continuously filled with inert gas. After the air is expelled, 60 parts of deionized water, 0.16-0.18 parts of emulsifier, and 0.1 parts of potassium persulfate are added, and the mixture is heated and stirred at a stirring speed of 60 rpm and a heating rate of 10°C / min. When the temperature reaches 70°C, a mixed solution of 0.3-0.5 parts of allyl methacrylate and 16-19 parts of 2-phenyl-1,3-butadiene is added dropwise. After the addition is completed, stirring is continued for 1 hour at a stirring speed of 150-250 rpm. A mixed solution of 3-5 parts of N-phenylmaleimide, 0.1 parts of potassium persulfate, and 3-4 parts of deionized water is added dropwise. After the addition is completed, stirring is continued for 1 hour at a stirring speed of 150-250 rpm to obtain an elastomer latex. (2) A three-necked flask is continuously filled with inert gas, and 17-19 parts of elastomer latex, 50 parts of deionized water, and 0.1 parts of potassium persulfate are added, and heated to 70°C with a stirring speed of 60 rpm and a heating rate of 10°C / min; then 3.5-4 parts of glycidyl methacrylate are added dropwise for 30 minutes; after the reaction for 1 hour, 3-4 parts of styrene are added dropwise for 30 minutes and maintained for 1 hour; after salting out and condensing with aluminum trichloride solution, the filtrate is filtered and centrifuged for dehydration, washed with deionized water 3 times, and dried at 50°C for 5-8 hours to obtain a powdered polymer heat-resistant crosslinking agent; (3) Octamethylcyclotetrasiloxane, hydroxy silicone oil and catalyst were mixed in a weight ratio of 100:0.1-0.2:0.3-0.5, added to a three-necked flask, evacuated to 0.01 MPa at 60 ° C, and then introduced nitrogen. The temperature was raised to 80-100 ° C and the reaction was continued for 1-3 hours; the temperature was raised to 100-120 ° C and the reaction was continued for 1-3 hours; the temperature was raised to above 160-180 ° C and the evacuation was carried out for 0.5-1.5 hours to obtain terminal hydroxyl polydimethylsiloxane; 2-3 parts of maleic anhydride and 0.2-4 parts of terminal hydroxyl polydimethylsiloxane were weighed and added to the beaker. 20 parts of acetone were poured into the mixture to dissolve it, and stirred at 120 rpm until it was completely dissolved; the dissolved mixed solution was then poured into a high-speed mixer containing POE and stirred for 5 minutes at a stirring speed of 400 rpm; finally, the mixed material was injected into a twin-screw extruder, wherein the extruder barrel head temperature was 170-190°C, the main engine speed was 300 r / min, the feed speed was 10 r / min, and the vacuum degree of the vacuum section was 0.05-0.09 MPa; the twin-screw extruder was extruded into filaments, which were then cooled with deionized water and finally dried at room temperature for 24 hours to obtain the modified POE resin; (4) 100 parts of PVC resin, 2-3 parts of stabilizer, 8-18 parts of modified POE resin, 50-55 parts of trioctyl trimellitate, and 0.5-0.8 parts of heat-resistant crosslinking agent are accurately weighed according to the formula and placed in a high-speed mixer at a speed of 1250-1450 rpm for mixing. When the temperature rises to 95-105 ° C, the material is discharged into a low-speed mixer at a speed of 70-100 rpm and cooled to 25-35 ° C before discharging; then the material is added to a double-roll open mill for mixing and sheeting, and the roller temperature of the double-roll open mill is 110-120 ° C; finally, the sheet is pressed in a molding machine at 160-180 ° C for 8-10 minutes and then cooled to obtain a transparent high-temperature resistant PVC crystal plate.

2. The method for preparing a transparent high-temperature resistant PVC crystal plate according to claim 1, characterized in that: The emulsifier in step (1) is an anionic emulsifier OT.

3. The method for preparing a transparent high-temperature resistant PVC crystal plate according to claim 1, characterized in that: The dropwise addition time in step (1) is 1 h.

4. The method for preparing a transparent high-temperature resistant PVC crystal plate according to claim 1, characterized in that: The inert gas in steps (1) and (2) is nitrogen.

5. The method for preparing a transparent high-temperature resistant PVC crystal plate according to claim 1, characterized in that: In step (2), the centrifugal speed is 12000-20000 rpm and the time is 20 min.

6. The method for preparing a transparent high-temperature resistant PVC crystal plate according to claim 1, characterized in that: The catalyst in step (3) is tetramethylammonium hydroxide siliconate.

7. The method for preparing a transparent high-temperature resistant PVC crystal plate according to claim 1, characterized in that: In step (3), the weight ratio of POE to the mixed solution is 100:0.5-1.

5.

8. The method for preparing a transparent high-temperature resistant PVC crystal plate according to claim 1, characterized in that: In step (3), the temperature of the high-speed mixer during stirring is 200-300°C.

9. The method for preparing a transparent high-temperature resistant PVC crystal plate according to claim 1, characterized in that: The stabilizer in step (4) is liquid barium zinc.

10. The method for preparing a transparent high-temperature resistant PVC crystal plate according to claim 1, characterized in that: The mixing time in step (4) is 300-500s.

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