High-strength PVC wood grain sheet and preparation method thereof

Abstract

The invention belongs to the technical field of PVC decorative materials, and particularly relates to a high-strength PVC wood grain sheet and a preparation method thereof. According to the invention, the oyster shell powder is modified by sodium hydroxide and sodium stearate, and then is subjected to secondary modification by a silane coupling agent KH-550, so that the prepared modified filler has the effects of enhancing the strength and antibacterial property of the PVC wood grain sheet; rapeseed oil, polyether glycol and isophorone diisocyanate are subjected to a reaction to prepare rapeseed oil-based waterborne polyurethane, then water is added for emulsification to prepare modified polyurethane emulsion, and the modified polyurethane emulsion can generate a good scattering effect on light rays; the wear-resistant additive prepared by reacting catechol modified hexagonal boron nitride powder with silicon carbide powder improves the wear resistance and heat resistance of the PVC wood grain sheet. The UV high-temperature-resistant coating is firstly coated and cured, then the transparent layer, the color film layer and the substrate layer are subjected to hot pressing, and the prepared high-strength PVC wood grain sheet product is clear in wood grain pattern, uniform in surface and excellent in mechanical property and antibacterial capacity.

Description

Technical Field

[0001] The invention belongs to the technical field of PVC decorative materials, and particularly relates to a high-strength PVC wood grain sheet and a preparation method thereof. Background Art

[0002] As a decorative material with imitation wood texture, polyvinyl chloride (PVC) wood grain sheet has been widely used in indoor and outdoor decoration. PVC has excellent flame retardancy, insulation and corrosion resistance, but it is brittle during processing and must be modified by a series of factors such as impact resistance and toughening before it can be used, which increases the application cost of the product accordingly.

[0003] The Chinese invention patent with publication number CN110819038B discloses a PVC sheet and a preparation method thereof, which relates to the technical field of polymer materials. The raw materials include the following components by weight: 80-90 parts of PVC; 5-6 parts of NBR; 1-3 parts of PS; 2-3 parts of methyl tin mercaptide; 1.5-3 parts of internal lubricant; 0.5-1 parts of external lubricant; 0.4-0.5 parts of antioxidant. NBR can give PVC sheet good impact strength and toughness. In addition to toughening the system, NBR can also effectively improve the thermal oxidation aging performance of the system and increase the service life of PVC sheets. PS and PVC have poor compatibility, so that there is a clear interface between PS particles and PVC matrix, and there are tiny holes around PS particles. These holes are generated after the melt mixing is cooled due to the different shrinkage rates of the two phases. When the material is impacted, these tiny holes deform and absorb energy, and when the rigid particles are forced to separate from the matrix, they also absorb energy, thereby improving the impact strength of the system. However, the prior art has the technical problem that the strength and antibacterial properties of the PVC wood grain sheet and the surface unevenness of the UV curing paint cannot be improved by further improving the PVC production process and raw materials. Summary of the invention

[0004] The purpose of the present invention is to provide a high-strength PVC wood grain sheet and a preparation method thereof, so as to solve the technical problem that the prior art has not further improved the PVC production process and raw materials to improve the strength and antibacterial properties of the PVC wood grain sheet and the surface unevenness of the UV curing paint.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions: High-strength PVC wood grain sheet, with UV high temperature resistant coating, transparent layer, color film layer and base material layer from top to bottom; The UV high temperature resistant coating includes the following raw materials by mass: 60-80 parts of modified polyurethane emulsion, 2-3 parts of leveling agent, 1-5 parts of wear-resistant additive and 2-5 parts of photoinitiator; The transparent layer comprises the following raw materials by weight: 80-100 parts of polyvinyl chloride resin, 20-60 parts of modified filler, 20-30 parts of toughening agent, 20-60 parts of plasticizer, 0.5-2 parts of stabilizer, 0.5-2 parts of lubricant and 0.1-1 parts of antioxidant; The color film layer includes the following raw materials by weight: 80-100 parts of polyvinyl chloride resin, 20-60 parts of modified filler, 8-15 parts of masterbatch, 20-30 parts of toughening agent, 20-60 parts of plasticizer, 0.5-2 parts of stabilizer, 0.5-2 parts of lubricant and 0.1-1 parts of antioxidant; The base material layer comprises the following raw materials in parts by mass: 80-100 parts of polyvinyl chloride resin, 80-100 parts of modified filler, 20-30 parts of toughening agent, 20-60 parts of plasticizer, 0.5-2 parts of stabilizer, 0.5-2 parts of lubricant and 0.1-1 parts of antioxidant.

[0006] The thickness of the base material layer is 1-3.5 mm, the thickness of the transparent layer is 0.1-2 mm, and the thickness of the high-strength PVC wood grain sheet is 2.5-6.5 mm.

[0007] The photoinitiator of the UV high temperature resistant coating is one or more combinations of benzophenones, hydroxy ketones, and alkyl phenones; the leveling agent is one or more combinations of butyl acetate cellulose, silicone resins, and polyacrylates.

[0008] The plasticizers of the transparent layer, color film layer and base material layer are all one or more combinations of diisononyl phthalate, epoxy soybean oil and dipentaerythritol ester; the toughening agents are all one or more combinations of EVA, MBS and PCL; the stabilizers are all one or more combinations of trioctyl phosphite, stearyl benzoylmethane and isooctyl tin dimethyl dimercaptoacetate; the lubricants are all one or more combinations of sodium stearate, zinc stearate and calcium stearate; and the antioxidants are all one or more combinations of 168, 1098 and 9228.

[0009] Preferably, the method for preparing the modified filler comprises the following steps: S11. According to mass parts, 50-100 parts of oyster shell powder are passed through a 300-400 mesh sieve, added to 100-200 parts of deionized water, and after ultrasonic dispersion, 0.3-0.5 parts of sodium hydroxide and 0.5-2 parts of sodium stearate are added, reacted at 75-80° C. for 0.5-1.5 h, filtered, dried at 70-80° C., and ground to obtain surface-modified oyster shell powder; S12. Add 50-100 parts of surface modified oyster shell powder and 1-2.5 parts of silane coupling agent KH-550 to 300-500 parts of anhydrous ethanol, ultrasonicate for 30-40 minutes, react at 70-80°C for 24-36 hours, filter and dry, and then roast at 500-600°C for 2-3 hours. Add 5-10 parts of wood powder and 10-20 parts of cellulose powder and ball-mill for 30-40 minutes to obtain a modified filler.

[0010] Preferably, the method for preparing the modified polyurethane emulsion comprises the following steps: S21. By mass, 3 to 5 parts of isophorone diisocyanate are added to a reactor, 10 to 20 parts of a polyether diol, 30 to 40 parts of rapeseed oil and 0.5 to 2 parts of a catalyst are added, and the mixture is reacted at 80 to 90° C. for 2 to 3 hours, 3 to 5 parts of 2,2-dihydroxymethylbutyric acid and 2 to 4 parts of trimethylolpropane are added, and the mixture is reacted for 1 to 2 hours, the temperature is reduced to 60 to 70° C., 5 to 10 parts of a blocking agent are added, the reaction is carried out for 6 to 8 hours, the temperature is reduced to 40 to 50° C., and 10 to 15 parts of triethylamine are added for neutralization to obtain a rapeseed oil-based waterborne polyurethane; S22. Add 20-30 parts of rapeseed oil-based waterborne polyurethane and 50-60 parts of deionized water into an emulsifier by mass, stir and emulsify at high speed for 1-2 hours to obtain a modified polyurethane emulsion.

[0011] Preferably, the catalyst in S21 is one or more combinations of dibutyltin dilaurate, triethylphosphine, and diethyltin octanoate.

[0012] Preferably, the end-capping agent in S21 is one or more combinations of hydroxyethyl methacrylate, caprolactam and hydroxypropyl acrylate.

[0013] Preferably, the method for preparing the wear-resistant additive comprises the following steps: S31. By mass, add 1.4 parts of tris(hydroxymethyl)aminomethane to 250-300 parts of deionized water, add 5-10wt% hydrochloric acid to adjust the pH to 8.5 to prepare a buffer solution, dissolve 0.6-0.8 parts of catechol in the buffer solution, add 1-2 parts of hexagonal boron nitride powder with an average particle size of 10-20 μm, ultrasonicate for 1-2 hours, react for 18-24 hours, filter and dry at 50-60°C to obtain modified hexagonal boron nitride; S32. Add 1-2 parts of modified hexagonal boron nitride to 200-300 parts of N,N-dimethylformamide, add 1-2 parts of silicon carbide powder with an average particle size of 50-100 nm after ultrasonic dispersion, react at 90-110°C for 12-24 hours, filter and dry to obtain a wear-resistant additive.

[0014] The preparation method of high-strength PVC wood grain sheet comprises the following steps: S1. Weigh the raw materials of the transparent layer, the color film layer and the base material layer, add them into a high-speed mixer respectively, and stir and premix them at 2000-3000 rpm for 5-15 minutes to obtain a mixed raw material of the transparent layer, the color film layer and the base material layer; S2, adding the mixed raw materials of the transparent layer, the color film layer and the base material layer to the calender respectively, and calendering to a specified thickness to obtain the transparent layer, the color film layer and the base material layer; S3, putting the photoinitiator into a mixer and adding 3-5 parts of an organic solvent to dissolve it, then putting the modified polyurethane emulsion, dispersant, and wear-resistant additive into the mixer for premixing to obtain a UV coating, and applying the UV coating on the transparent layer by a roller coater, curing it by ultraviolet light, and then superimposing the transparent layer, the color film layer, and the base material layer from top to bottom and hot pressing for 20-30 minutes to obtain a crude PVC wood grain sheet; S4. Punch the crude PVC wood grain sheet into specified specifications and package to obtain high-strength PVC wood grain sheet products.

[0015] Preferably, the calendering temperature of the calender in S2 is 160-180° C., and the calendering time is 20-40 min.

[0016] Preferably, the organic solvent in S3 is one or more combinations of methanol, ethanol and isopropanol.

[0017] Preferably, the thickness of the UV coating in S3 is 50-150 μm.

[0018] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are: 1. Based on the existing technology, the present invention optimizes the production process and component ratio of PVC wood grain sheets, first applies and cures the UV high temperature resistant coating, and then hot presses the transparent layer, the color film layer and the base material layer. The high-strength PVC wood grain sheet product has a clear wood grain pattern and a uniform surface, which solves the problem of uneven surface after hot pressing and then applying UV curing paint, and has excellent mechanical properties and antibacterial ability.

[0019] 2. The present invention modifies the surface hydroxyl content and dispersibility of oyster shell powder by sodium hydroxide and sodium stearate, and then performs secondary modification by silane coupling agent KH-550. The obtained modified filler has excellent antibacterial ability. The modified filler is applied to PVC wood grain sheets to improve the strength, toughness and impact resistance of the PVC wood grain sheets.

[0020] 3. The present invention obtains rapeseed oil-based waterborne polyurethane by reacting rapeseed oil, polyether diol and isophorone diisocyanate, and then adds water for emulsification to obtain a modified polyurethane emulsion, which can form a micrometer-scale rough structure after curing, can produce a good scattering effect on light, reduce the reflection degree of the PVC surface, and improve the texture of the wood grain sheet.

[0021] 4. The wear-resistant additive prepared by the present invention is prepared by modifying hexagonal boron nitride powder with catechol and then reacting it with silicon carbide powder. Both hexagonal boron nitride and silicon carbide have excellent wear resistance and heat resistance. They are combined through the reaction with catechol and have strong interface bonding force, thereby improving the wear resistance and heat resistance of the PVC wood grain sheet. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0023] Figure 1 A schematic diagram showing the hierarchical structure of the high-strength PVC wood grain sheet of the present invention is shown; Explanation of reference numerals: 1-UV high temperature resistant coating, 2-transparent layer, 3-color film layer, 4-substrate layer. DETAILED DESCRIPTION

[0024] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments 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 creative work are within the scope of protection of the present invention.

[0025] The polyvinyl chloride resin involved in the embodiments and comparative examples of the present invention has a model of SG5 and is purchased from Shanghai Jiachen Chemical Co., Ltd.

[0026] Example 1, see Figure 1 As shown, the high-strength PVC wood grain sheet of this embodiment is provided with a UV high temperature resistant coating 1, a transparent layer 2, a color film layer 3 and a base material layer 4 in sequence from top to bottom; The UV high temperature resistant coating comprises the following raw materials by mass: 60 parts of modified polyurethane emulsion, 2 parts of leveling agent, 3 parts of wear resistant additive and 2 parts of photoinitiator; The transparent layer comprises the following raw materials by mass: 80 parts of polyvinyl chloride resin, 40 parts of modified filler, 20 parts of toughening agent, 20 parts of plasticizer, 1 part of stabilizer, 1 part of lubricant and 0.5 part of antioxidant; The color film layer includes the following raw materials by mass: 80 parts of polyvinyl chloride resin, 20 parts of modified filler, 8 parts of masterbatch, 20 parts of toughening agent, 20 parts of plasticizer, 1 part of stabilizer, 1 part of lubricant and 0.5 parts of antioxidant; The base material layer comprises the following raw materials by mass: 80 parts of polyvinyl chloride resin, 80 parts of modified filler, 20 parts of toughening agent, 30 parts of plasticizer, 1 part of stabilizer, 1 part of lubricant and 0.5 part of antioxidant.

[0027] The thickness of the base material layer is 1.5 mm, the thickness of the transparent layer is 1 mm, and the thickness of the high-strength PVC wood grain sheet is 3 mm.

[0028] The photoinitiator of the UV high temperature resistant coating is a benzophenone photoinitiator, model 522; the leveling agent is a butyl acetate cellulose leveling agent, model CAB-381-2.

[0029] The plasticizers of the transparent layer, the color film layer and the base material layer are all epoxidized soybean oil; the toughening agents are all EVA; the stabilizers are all trioctyl phosphite; the lubricants are all sodium stearate; and the antioxidants are all 168 and 1098 mixed in a mass ratio of 1:1.

[0030] The preparation method of the modified filler of this embodiment comprises the following steps: S11. According to parts by mass, 100 parts of oyster shell powder were passed through a 400-mesh sieve, added to 200 parts of deionized water, and after ultrasonic dispersion, 0.5 parts of sodium hydroxide and 2 parts of sodium stearate were added, reacted at 80° C. for 1 h, filtered, dried at 70-80° C., and ground to obtain surface-modified oyster shell powder; S12. Add 100 parts of surface modified oyster shell powder and 2.5 parts of silane coupling agent KH-550 to 500 parts of anhydrous ethanol by mass, ultrasonicate for 40 minutes, react at 80°C for 24 hours, filter and dry, and then roast at 600°C for 2 hours. Add 5 parts of wood powder and 10 parts of cellulose powder and ball-mill for 30 minutes to obtain a modified filler.

[0031] The preparation method of the modified polyurethane emulsion of this embodiment comprises the following steps: S21, by mass, add 5 parts of isophorone diisocyanate to a reactor, add 15 parts of polyether diol-2000, 40 parts of rapeseed oil and 2 parts of dibutyltin dilaurate, react at 90°C for 2h, add 3 parts of 2,2-dihydroxymethylbutyric acid and 2 parts of trimethylolpropane to react for 1h, reduce the temperature to 60°C, add 8 parts of hydroxyethyl methacrylate to react for 6h, reduce the temperature to 50°C, add 15 parts of triethylamine to neutralize, and prepare rapeseed oil-based waterborne polyurethane; S22. Add 20 parts of rapeseed oil-based waterborne polyurethane and 60 parts of deionized water into an emulsifier by mass, stir and emulsify at high speed for 2 hours to obtain a modified polyurethane emulsion.

[0032] The preparation method of the wear-resistant additive of this embodiment comprises the following steps: S31. By mass, 1.4 parts of tris(hydroxymethyl)aminomethane were added to 300 parts of deionized water, and 10 wt % of hydrochloric acid was added to adjust the pH to 8.5 to prepare a buffer solution, 0.8 parts of catechol were dissolved in the buffer solution, 2 parts of hexagonal boron nitride powder with an average particle size of 15 μm were added, ultrasonicated for 2 hours, reacted for 24 hours, filtered and dried at 50° C. to obtain modified hexagonal boron nitride; S32. Add 2 parts of modified hexagonal boron nitride to 200 parts of N,N-dimethylformamide, add 2 parts of silicon carbide powder with an average particle size of 90 nm after ultrasonic dispersion, react at 100°C for 24 hours, filter and dry to obtain a wear-resistant additive.

[0033] The method for preparing the high-strength PVC wood grain sheet of this embodiment comprises the following steps: S1. Weigh the raw materials of the base material layer, the color film layer and the transparent layer, add them into a high-speed mixer respectively, and stir and premix them at 2000 rpm for 10 minutes to obtain a mixed raw material of the transparent layer, the color film layer and the base material layer; S2, adding the mixed raw materials of the transparent layer, the color film layer and the base material layer to the calender respectively, the calendering temperature is 170°C, the calendering time is 30min, and the calendering is performed to a specified thickness to obtain the transparent layer, the color film layer and the base material layer; S3, after the photoinitiator is put into a blender and added with 5 parts of methanol to dissolve, the modified polyurethane emulsion, dispersant and wear-resistant additive are put into the blender for premixing to obtain UV coating, and the UV coating is applied on the transparent layer by a roller coater, with a coating thickness of 100 μm. After curing by ultraviolet light, the transparent layer, the color film layer and the base material layer are overlapped from top to bottom and hot pressed for 30 minutes to obtain a crude PVC wood grain sheet; S4. Punch the crude PVC wood grain sheet into specified specifications and package to obtain high-strength PVC wood grain sheet products.

[0034] Example 2, see Figure 1 As shown, the high-strength PVC wood grain sheet of this embodiment is provided with a UV high temperature resistant coating, a transparent layer, a color film layer and a base material layer in sequence from top to bottom; The UV high temperature resistant coating comprises the following raw materials by mass: 70 parts of modified polyurethane emulsion, 3 parts of leveling agent, 4 parts of wear resistant additive and 2 parts of photoinitiator; The transparent layer comprises the following raw materials by mass: 100 parts of polyvinyl chloride resin, 40 parts of modified filler, 20 parts of toughening agent, 25 parts of plasticizer, 1 part of stabilizer, 1 part of lubricant and 1 part of antioxidant; The color film layer includes the following raw materials by mass: 100 parts of polyvinyl chloride resin, 20 parts of modified filler, 8 parts of masterbatch, 25 parts of toughening agent, 20 parts of plasticizer, 1 part of stabilizer, 1 part of lubricant and 1 part of antioxidant; The base material layer comprises the following raw materials by mass: 100 parts of polyvinyl chloride resin, 80 parts of modified filler, 25 parts of toughening agent, 40 parts of plasticizer, 1 part of stabilizer, 1 part of lubricant and 1 part of antioxidant.

[0035] The thickness of the base material layer is 3 mm, the thickness of the transparent layer is 1.5 mm, and the thickness of the high-strength PVC wood grain sheet is 4 mm.

[0036] The photoinitiator of the UV high temperature resistant coating is a hydroxyketone photoinitiator, model 500; the leveling agent is a silicone resin leveling agent, model BYK-310.

[0037] The plasticizers of the transparent layer, color film layer and base material layer are all diisononyl phthalate; the toughening agents are all MBS; the stabilizers are all stearylbenzoylmethane; the lubricants are all zinc stearate and calcium stearate mixed in a mass ratio of 1:3; the antioxidants are all 168 and 9228 mixed in a mass ratio of 1:1.

[0038] The preparation method of the modified filler and modified polyurethane emulsion in this embodiment is the same as the preparation method in Example 1.

[0039] The difference between the wear-resistant additive of this embodiment and that of embodiment 1 is that the average particle size of the hexagonal boron nitride powder is 10 μm, and the average particle size of the silicon carbide powder is 55 nm.

[0040] The method for preparing the high-strength PVC wood grain sheet of this embodiment comprises the following steps: S1. Weigh the raw materials of the transparent layer, the color film layer and the base material layer, add them into a high-speed mixer respectively, and stir and premix them at 2500 rpm for 15 minutes to obtain a mixed raw material of the transparent layer, the color film layer and the base material layer; S2, adding the mixed raw materials of the transparent layer, the color film layer and the base material layer to the calender respectively, the calendering temperature is 175°C, the calendering time is 25min, and the calendering is performed to a specified thickness to obtain the transparent layer, the color film layer and the base material layer; S3, after the photoinitiator is dissolved in 3 parts of ethanol in a blender, the modified polyurethane emulsion, dispersant and wear-resistant additive are pre-mixed in the blender to obtain a UV coating, and the UV coating is applied on the transparent layer by a roller coater, with a coating thickness of 145 μm. After curing by ultraviolet light, the transparent layer, the color film layer and the base material layer are overlapped from top to bottom and hot-pressed for 30 minutes to obtain a crude PVC wood grain sheet; S4. Punch the crude PVC wood grain sheet into specified specifications and package to obtain high-strength PVC wood grain sheet products.

[0041] Example 3, see Figure 1 As shown, the high-strength PVC wood grain sheet of this embodiment is provided with a UV high temperature resistant coating, a transparent layer, a color film layer and a base material layer in sequence from top to bottom; The UV high temperature resistant coating comprises the following raw materials by mass: 70 parts of modified polyurethane emulsion, 3 parts of leveling agent, 4 parts of wear resistant additive and 2 parts of photoinitiator; The transparent layer comprises the following raw materials by mass: 90 parts of polyvinyl chloride resin, 60 parts of modified filler, 20 parts of toughening agent, 25 parts of plasticizer, 1 part of stabilizer, 1 part of lubricant and 1 part of antioxidant; The color film layer includes the following raw materials by mass: 100 parts of polyvinyl chloride resin, 20 parts of modified filler, 8 parts of masterbatch, 25 parts of toughening agent, 20 parts of plasticizer, 1 part of stabilizer, 1 part of lubricant and 1 part of antioxidant; The base material layer comprises the following raw materials in parts by mass: 100 parts of polyvinyl chloride resin, 80 parts of modified filler, 25 parts of toughening agent, 40 parts of plasticizer, 1 part of stabilizer, 1 part of lubricant and 1 part of antioxidant.

[0042] The thickness of the base material layer is 3.5 mm, the thickness of the transparent layer is 0.5 mm, and the thickness of the high-strength PVC wood grain sheet is 5 mm.

[0043] The photoinitiator of the UV high temperature resistant coating is an alkyl phenone photoinitiator, model 2959; the leveling agent is a polyacrylate leveling agent, model BYK-390.

[0044] The plasticizers of the transparent layer, color film layer and base material layer are all dipentaerythritol ester; the toughening agents are all PCL; the stabilizers are all isooctyl tin dimethyl dimercaptoacetate; the lubricants are all zinc stearate and calcium stearate mixed in a mass ratio of 1:3; the antioxidants are all 1098 and 9228 mixed in a mass ratio of 1:1.

[0045] The preparation method of the modified filler and the wear-resistant additive in this embodiment is the same as the preparation method in Example 1.

[0046] The difference between the modified polyurethane emulsion of this embodiment and that of embodiment 1 is that the catalyst is replaced by triethylphosphine and the end-capping agent is replaced by caprolactam.

[0047] The method for preparing the high-strength PVC wood grain sheet of this embodiment comprises the following steps: S1. Weigh the raw materials of the transparent layer, the color film layer and the base material layer, add them into a high-speed mixer respectively, and stir and premix them at 3000 rpm for 5 minutes to obtain a mixed raw material of the transparent layer, the color film layer and the base material layer; S2, adding the mixed raw materials of the transparent layer, the color film layer and the base material layer to the calender respectively, the calendering temperature is 180°C, the calendering time is 35min, and the calendering is performed to a specified thickness to obtain the transparent layer, the color film layer and the base material layer; S3, after the photoinitiator is dissolved in 5 parts of isopropanol in a blender, the modified polyurethane emulsion, dispersant and wear-resistant additive are pre-mixed in the blender to obtain a UV coating, and the UV coating is applied on the transparent layer by a roller coater, with a coating thickness of 60 μm. After curing by ultraviolet light, the transparent layer, the color film layer and the base material layer are overlapped from top to bottom and hot-pressed for 20 minutes to obtain a crude PVC wood grain sheet; S4. Punch the crude PVC wood grain sheet into specified specifications and package to obtain high-strength PVC wood grain sheet products.

[0048] Comparative Example 1: The difference between this comparative example and Example 1 is that the modified filler is directly prepared by ball-milling unmodified oyster shell powder, wood powder and cellulose powder.

[0049] Comparative Example 2: The difference between this comparative example and Example 1 is that the raw material polyether diol-2000 of the modified polyurethane emulsion is replaced by polyether diol-6000.

[0050] Comparative Example 3: The difference between this comparative example and Example 1 is that the wear-resistant additive is replaced by alumina powder.

[0051] Performance Testing The surface hardness of the PVC wood grain sheets prepared in each embodiment and comparative example was tested according to GB / T 6739-2006 “Determination of paint film hardness by pencil method for paints and varnishes”.

[0052] The wear rates of the PVC wood grain sheets prepared in the embodiments and comparative examples were tested according to GB3960-83 “Test methods for sliding friction and wear of plastics”.

[0053] According to GB / T 1040.2-2022 “Determination of tensile properties of plastics Part 2: Test conditions for molded and extruded plastics”, the tensile strength and elongation at break of the PVC wood grain sheets prepared in each embodiment and comparative example were tested.

[0054] The notched impact strength of the PVC wood grain sheets prepared in the embodiments and comparative examples was tested according to GB / T1843-2008 "Plastic Izod Beam Impact Test Method".

[0055] The test results are shown in Table 1 below: Table 1 Performance test results

[0056] According to the data in the above table, the surface hardness of the PVC wood grain sheets prepared in Examples 1 to 3 is 3H, and the wear rate is 0.06g / 100r, indicating that the PVC wood grain sheets prepared in the present invention have excellent wear resistance; the tensile strength of the PVC wood grain sheets prepared in Examples 1 to 3 is between 46.3 and 46.4MPa, the elongation at break is between 53.9 and 54.3%, and the notched impact strength is between 9.3 and 9.6kJ / m 2 The oyster shell powder of the modified filler in Comparative Example 1 is not modified, so the dispersion performance in the PVC wood grain sheet is poor, resulting in a downward trend in tensile strength and elongation at break, indicating that the PVC wood grain sheet prepared by the present invention has excellent impact resistance and high strength.

[0057] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

[0058] The preferred embodiments of the present invention disclosed above are only used to help explain the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to only specific implementation methods. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. High-strength PVC wood grain sheet, characterized in that: From top to bottom, UV high temperature resistant coating, transparent layer, color film layer and base material layer are arranged in sequence; The UV high temperature resistant coating includes the following raw materials by mass: 60-80 parts of modified polyurethane emulsion, 2-3 parts of leveling agent, 1-5 parts of wear resistant additive and 2-5 parts of photoinitiator; The transparent layer comprises the following raw materials by weight: 80-100 parts of polyvinyl chloride resin, 20-60 parts of modified filler, 20-30 parts of toughening agent, 20-60 parts of plasticizer, 0.5-2 parts of stabilizer, 0.5-2 parts of lubricant and 0.1-1 parts of antioxidant; The color film layer includes the following raw materials by weight: 80-100 parts of polyvinyl chloride resin, 20-60 parts of modified filler, 8-15 parts of masterbatch, 20-30 parts of toughening agent, 20-60 parts of plasticizer, 0.5-2 parts of stabilizer, 0.5-2 parts of lubricant and 0.1-1 parts of antioxidant; The base material layer comprises the following raw materials in parts by mass: 80-100 parts of polyvinyl chloride resin, 80-100 parts of modified filler, 20-30 parts of toughening agent, 20-60 parts of plasticizer, 0.5-2 parts of stabilizer, 0.5-2 parts of lubricant and 0.1-1 parts of antioxidant.

2. The high-strength PVC wood grain sheet according to claim 1, characterized in that: The thickness of the base material layer is 1-3.5 mm, the thickness of the transparent layer is 0.1-2 mm, and the thickness of the high-strength PVC wood grain sheet is 2.5-6.5 mm.

3. The high-strength PVC wood grain sheet according to claim 1, characterized in that: The photoinitiator of the UV high temperature resistant coating is one or more combinations of benzophenones, hydroxy ketones, and alkyl phenones; the leveling agent is one or more combinations of butyl acetate cellulose, silicone resins, and polyacrylates.

4. The high-strength PVC wood grain sheet according to claim 1, characterized in that: The plasticizers of the transparent layer, color film layer and base material layer are all one or more combinations of diisononyl phthalate, epoxy soybean oil and dipentaerythritol; the toughening agents are all one or more combinations of EVA, MBS and PCL; the stabilizers are all one or more combinations of trioctyl phosphite, stearyl benzoylmethane and isooctyl tin dimethyl dimercaptoacetate; the lubricants are all one or more combinations of sodium stearate, zinc stearate and calcium stearate; and the antioxidants are all one or more combinations of 168, 1098 and 9228.

5. The high-strength PVC wood grain sheet according to claim 1, characterized in that: The preparation method of the modified filler comprises the following steps: S11. According to mass parts, 50-100 parts of oyster shell powder are passed through a 300-400 mesh sieve, added to 100-200 parts of deionized water, and after ultrasonic dispersion, 0.3-0.5 parts of sodium hydroxide and 0.5-2 parts of sodium stearate are added, reacted at 75-80° C. for 0.5-1.5 h, filtered, dried at 70-80° C., and ground to obtain surface-modified oyster shell powder; S12. Add 50-100 parts of surface modified oyster shell powder and 1-2.5 parts of silane coupling agent KH-550 to 300-500 parts of anhydrous ethanol, ultrasonicate for 30-40 minutes, react at 70-80°C for 24-36 hours, filter and dry, and then roast at 500-600°C for 2-3 hours. Add 5-10 parts of wood powder and 10-20 parts of cellulose powder and ball-mill for 30-40 minutes to obtain a modified filler.

6. The high-strength PVC wood grain sheet according to claim 1, characterized in that: The preparation method of the modified polyurethane emulsion comprises the following steps: S21. By mass, 3 to 5 parts of isophorone diisocyanate are added to a reactor, 10 to 20 parts of a polyether diol, 30 to 40 parts of rapeseed oil and 0.5 to 2 parts of a catalyst are added, and the mixture is reacted at 80 to 90° C. for 2 to 3 hours, 3 to 5 parts of 2,2-dihydroxymethylbutyric acid and 2 to 4 parts of trimethylolpropane are added, and the mixture is reacted for 1 to 2 hours, the temperature is reduced to 60 to 70° C., 5 to 10 parts of a blocking agent are added, the reaction is carried out for 6 to 8 hours, the temperature is reduced to 40 to 50° C., and 10 to 15 parts of triethylamine are added for neutralization to obtain a rapeseed oil-based waterborne polyurethane; S22. Add 20-30 parts of rapeseed oil-based waterborne polyurethane and 50-60 parts of deionized water into an emulsifier by mass, stir and emulsify at high speed for 1-2 hours to obtain a modified polyurethane emulsion.

7. The high-strength PVC wood grain sheet according to claim 6, characterized in that: The catalyst in S21 is one or more combinations of dibutyltin dilaurate, triethylphosphine, and diethyltin octanoate, and the end-capping agent is one or more combinations of hydroxyethyl methacrylate, caprolactam, and hydroxypropyl acrylate.

8. The high-strength PVC wood grain sheet according to claim 1, characterized in that: The preparation method of the wear-resistant additive comprises the following steps: S31. By mass, add 1.4 parts of tris(hydroxymethyl)aminomethane to 250-300 parts of deionized water, add 5-10wt% hydrochloric acid to adjust the pH to 8.5 to prepare a buffer solution, dissolve 0.6-0.8 parts of catechol in the buffer solution, add 1-2 parts of hexagonal boron nitride powder with an average particle size of 10-20 μm, ultrasonicate for 1-2 hours, react for 18-24 hours, filter and dry at 50-60°C to obtain modified hexagonal boron nitride; S32. Add 1-2 parts of modified hexagonal boron nitride to 200-300 parts of N,N-dimethylformamide, add 1-2 parts of silicon carbide powder with an average particle size of 50-100 nm after ultrasonic dispersion, react at 90-110°C for 12-24 hours, filter and dry to obtain a wear-resistant additive.

9. A method for preparing a high-strength PVC wood grain sheet, characterized in that: The steps include: S1. Weigh the raw materials of the transparent layer, the color film layer and the base material layer, add them into a high-speed mixer respectively, and stir and premix them at 2000-3000 rpm for 5-15 minutes to obtain a mixed raw material of the transparent layer, the color film layer and the base material layer; S2, adding the mixed raw materials of the transparent layer, the color film layer and the base material layer to the calender respectively, and calendering to a specified thickness to obtain the transparent layer, the color film layer and the base material layer; S3, putting the photoinitiator into a mixer and adding 3-5 parts of an organic solvent to dissolve it, then putting the modified polyurethane emulsion, dispersant, and wear-resistant additive into the mixer for premixing to obtain a UV coating, and applying the UV coating on the transparent layer by a roller coater, curing it by ultraviolet light, and then superimposing the transparent layer, the color film layer, and the base material layer from top to bottom and hot pressing for 20-30 minutes to obtain a crude PVC wood grain sheet; S4. Punch the crude PVC wood grain sheet into specified specifications and package to obtain high-strength PVC wood grain sheet products.

10. The method for preparing a high-strength PVC wood grain sheet according to claim 9, characterized in that: The calendering temperature of the calender in S2 is 160-180° C., and the calendering time is 20-40 min. The organic solvent in S3 is one or more combinations of methanol, ethanol, and isopropanol, and the coating thickness of the UV coating is 50-150 μm.

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