High-strength PVC wood grain sheet and method for preparing the same

Abstract

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

Description

TECHNICAL FIELD

[0001] The application 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

[0002] The PVC wood grain sheet, as a decorative material with wood grain texture, has been widely applied in indoor and outdoor decoration fields. PVC has excellent flame retardance, insulation and corrosion resistance, but is brittle in the processing process, and must be modified in a series of processes such as impact resistance and toughness, so that the product application cost is correspondingly increased.

[0003] A PVC sheet and a preparation method thereof are disclosed in Chinese Patent Publication No. CN110819038B, which belongs to the technical field of high polymer materials. The raw materials include the following components in parts by weight: PVC 80-90 parts; NBR 5-6 parts; PS 1-3 parts; thiol methyl tin 2-3 parts; internal lubricant 1.5-3 parts; external lubricant 0.5-1 part; antioxidant 0.4-0.5 part. NBR can give the PVC board 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 prolong the service life of the PVC sheet. PS has poor compatibility with PVC, so there is an obvious interface between PS particles and the PVC matrix, and there are fine cavities around the PS particles. These cavities are produced after melting, mixing and cooling due to the different shrinkage rates of the two phases. When the material is impacted, these tiny cavities 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, antibacterial performance and surface unevenness of the UV cured paint of the PVC wood grain sheet cannot be improved by further improving the PVC production process and raw materials. SUMMARY

[0004] The purpose of the present application is to provide a high-strength PVC wood grain sheet and a preparation method thereof, which solves the technical problem in the prior art that the strength, antibacterial performance and surface unevenness of the UV cured paint of the PVC wood grain sheet cannot be improved by further improving the PVC production process and raw materials.

[0005] In order to achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0006] The high-strength PVC wood grain sheet is provided with a UV high-temperature resistant coating layer, a transparent layer, a color film layer and a substrate layer from top to bottom.

[0007] The UV high-temperature resistant coating layer comprises the following raw materials in parts by mass: 60-80 parts of modified polyurethane emulsion, 2-3 parts of leveling agent, 1-5 parts of wear-resistant aid and 2-5 parts of photoinitiator.

[0008] The transparent layer comprises the following raw materials by mass fraction: 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 part of antioxidant;

[0009] The color film layer comprises the following raw materials by mass fraction: 80-100 parts of polyvinyl chloride resin, 20-60 parts of modified filler, 8-15 parts of color master batch, 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 part of antioxidant;

[0010] The substrate layer comprises the following raw materials by mass fraction: 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 part of antioxidant.

[0011] The thickness of the substrate 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.

[0012] The photoinitiator of the UV high-temperature resistant coating is one or more combinations of benzophenone, hydroxy ketone and alkyl phenone; the leveling agent is one or more combinations of butyl acetate cellulose, silicone resin and polyacrylate.

[0013] The plasticizer of the transparent layer, the color film layer and the substrate layer is one or more combinations of diisononyl phthalate, epoxy soybean oil and dipentaerythritol ester; the toughening agent is one or more combinations of EVA, MBS and PCL; the stabilizer is one or more combinations of trioctyl phosphite, stearyl benzoyl methane and dimethyl isooctyl tin dimercaptide; the lubricant is one or more combinations of sodium stearate, zinc stearate and calcium stearate; and the antioxidant is one or more combinations of 168, 1098 and 9228.

[0014] As preferred, the preparation method of the modified filler comprises the following steps:

[0015] S11, 50-100 parts of oyster shell powder is sieved through a 300-400 mesh sieve, 100-200 parts of deionized water is added, ultrasonic dispersion is performed, 0.3-0.5 parts of sodium hydroxide and 0.5-2 parts of sodium stearate are added, reaction is performed at 75-80℃ for 0.5-1.5 h, filtration is performed, drying is performed at 70-80℃, and grinding is performed to obtain surface modified oyster shell powder;

[0016] S12, by mass fraction, 50~100 parts of surface modified oyster shell powder and 1~2.5 parts of silane coupling agent KH-550 are added into 300~500 parts of anhydrous ethanol, ultrasonic for 30~40 min, reaction at 70~80℃ for 24~36h, after filtration and drying, calcination at 500~600℃ for 2~3h, 5~10 parts of wood powder and 10~20 parts of cellulose powder are ball milled for 30~40 min to prepare modified filler.

[0017] As preferred, the preparation method of the modified polyurethane emulsion comprises the following steps:

[0018] S21, by mass fraction, 3~5 parts of isophorone diisocyanate is added into a reaction kettle, 10~20 parts of polyether diol, 30~40 parts of rapeseed oil and 0.5~2 parts of catalyst are added, and then reaction at 80~90℃ for 2~3h, 3~5 parts of 2,2-dimethylol butyric acid and 2~4 parts of trimethylolpropane are added and reacted for 1~2h, the temperature is reduced to 60~70℃, 5~10 parts of capping agent is added and reacted for 6~8h, and then reduced to 40~50℃, 10~15 parts of triethylamine is added for neutralization to prepare rapeseed oil-based waterborne polyurethane;

[0019] S22, by mass fraction, 20~30 parts of rapeseed oil-based waterborne polyurethane and 50~60 parts of deionized water are added into an emulsifier, and then high-speed stirring and emulsification for 1~2h to obtain modified polyurethane emulsion.

[0020] As preferred, the catalyst in S21 is one or more combination of dibutyltin dilaurate, triethyl phosphine, and diethyltin octoate.

[0021] As preferred, the capping agent in S21 is one or more combination of hydroxyethyl methacrylate, caprolactam, and hydroxypropyl acrylate.

[0022] As preferred, the preparation method of the wear-resistant aid comprises the following steps:

[0023] S31, by mass fraction, 1.4 parts of tris-hydroxymethyl aminomethane is added into 250~300 parts of deionized water, 5~10wt% of hydrochloric acid is added to adjust the pH to 8.5 to prepare a buffer solution, 0.6~0.8 parts of catechol is dissolved in the buffer solution, 1~2 parts of hexagonal boron nitride powder with an average particle size of 10~20μm is added and ultrasonic for 1~2h, and then reaction for 18~24h, after filtration, drying at 50~60℃ to obtain modified hexagonal boron nitride;

[0024] S32, 1~2 parts of modified hexagonal boron nitride is added into 200~300 parts of N,N-dimethylformamide, ultrasonic dispersion, and then 1~2 parts of silicon carbide powder with an average particle size of 50~100nm is added, reaction at 90~110℃ for 12~24h, filtration and drying to prepare wear-resistant aid.

[0025] The preparation method of the high-strength PVC wood grain sheet comprises the following steps:

[0026] S1, the raw materials of the transparent layer, the color film layer and the substrate layer are weighed and added into a high-speed mixer respectively, and stirred at 2000-3000 rpm for 5-15 min to prepare the mixed raw materials of the transparent layer, the color film layer and the substrate layer;

[0027] S2, the mixed raw materials of the transparent layer, the color film layer and the substrate layer are added into a calender respectively, and calendered to a specified thickness to prepare the transparent layer, the color film layer and the substrate layer;

[0028] S3, the photoinitiator is dissolved in 3-5 parts of an organic solvent in a blender, and then the modified polyurethane emulsion, the dispersing agent and the wear-resistant auxiliary agent are added into the blender to prepare a UV coating, the UV coating is applied on the transparent layer by a roll coater, and then ultraviolet light is irradiated to solidify, and then the transparent layer, the color film layer and the substrate layer are stacked from top to bottom and hot-pressed for 20-30 min to prepare a PVC wood grain sheet crude product;

[0029] S4, the PVC wood grain sheet crude product is cut into a specified size to prepare a high-strength PVC wood grain sheet product.

[0030] Preferably, the calendering temperature of the calender in S2 is 160-180℃, and the calendering time is 20-40 min.

[0031] Preferably, the organic solvent in S3 is one or more combinations of methanol, ethanol and isopropanol.

[0032] Preferably, the thickness of the UV coating applied in S3 is 50-150 μm.

[0033] As described above, due to the adoption of the above technical solutions, the present application has the following advantages:

[0034] 1. Based on the prior art, the present application optimizes the production process and component ratio of the PVC wood grain sheet, coats and solidifies a UV high-temperature resistant coating first, and then hot-presses the transparent layer, the color film layer and the substrate layer to prepare a high-strength PVC wood grain sheet product with clear wood grain patterns and uniform surface, which solves the problem of uneven surface caused by hot-pressing first and then coating and solidifying the UV coating, and has excellent mechanical properties and antibacterial ability.

[0035] 2. The present application modifies the surface hydroxyl content and dispersibility of oyster shell powder by sodium hydroxide and sodium stearate, and then modifies it again by silane coupling agent KH-550 to prepare a modified filler with excellent antibacterial ability, which is applied to the PVC wood grain sheet to improve the strength, toughness and impact resistance of the PVC wood grain sheet.

[0036] 3、The rapeseed oil based waterborne polyurethane is prepared by the reaction of rapeseed oil, polyether diol and isophorone diisocyanate, and the modified polyurethane emulsion is prepared by adding water to emulsify, and the rough structure of micron scale can be formed after curing, the light can be well scattered, the reflection degree of the PVC surface is reduced, and the texture of the wood grain sheet is improved.

[0037] 4、The wear-resistant aid is prepared by the reaction of the modified hexagonal boron nitride powder and the silicon carbide powder, the hexagonal boron nitride and the silicon carbide have excellent wear resistance and heat resistance, the interface bonding force is high through the reaction combination of the pyrocatechol, and the wear resistance and the heat resistance of the PVC wood grain sheet are improved. BRIEF DESCRIPTION OF DRAWINGS

[0038] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced below, and obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0039] Figure 1 The schematic diagram of the hierarchical structure of the high-strength PVC wood grain sheet is shown;

[0040] The figure mark explanation: 1-UV high-temperature resistant coating, 2-transparent layer, 3-color film layer, 4-substrate layer. DETAILED DESCRIPTION

[0041] The technical solutions in the embodiments of the present application will be described clearly and completely below in combination with the drawings in the embodiments of the present application, and obviously, the described embodiments are only some embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor belong to the protection scope of the present application.

[0042] The polyvinyl chloride resin involved in the examples and the comparative examples of the present application is SG5, which is purchased from Shanghai Jiachen Chemical Co., Ltd.

[0043] Example 1, refer to Figure 1 The high-strength PVC wood grain sheet of the present embodiment is sequentially provided with a UV high-temperature resistant coating 1, a transparent layer 2, a color film layer 3 and a substrate layer 4 from top to bottom.

[0044] The UV high-temperature resistant coating includes the following raw materials by mass fraction: 60 parts of modified polyurethane emulsion, 2 parts of leveling agent, 3 parts of wear-resistant aid and 2 parts of photoinitiator.

[0045] The transparent layer comprises the following raw materials by mass fraction: 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;

[0046] The color film layer comprises the following raw materials by mass fraction: 80 parts of polyvinyl chloride resin, 20 parts of modified filler, 8 parts of color master batch, 20 parts of toughening agent, 20 parts of plasticizer, 1 part of stabilizer, 1 part of lubricant and 0.5 part of antioxidant;

[0047] The substrate layer comprises the following raw materials by mass fraction: 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.

[0048] The thickness of the substrate 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.

[0049] The photoinitiator of the UV high-temperature resistant coating is a benzophenone photoinitiator with model number 522, and the leveling agent is a cellulose acetate butyl ester leveling agent with model number CAB-381-2.

[0050] The plasticizer of the transparent layer, the color film layer and the substrate layer is all epoxy soybean oil; the toughening agent is all EVA; the stabilizer is all tricoctyl phosphite; the lubricant is all sodium stearate; and the antioxidant is all a mixture of 168 and 1098 in a mass ratio of 1:1.

[0051] The preparation method of the modified filler of the embodiment comprises the following steps:

[0052] S11, 100 parts of oyster shell powder are sieved through a 400-mesh sieve, and then added into 200 parts of deionized water, ultrasonic dispersion, 0.5 parts of sodium hydroxide and 2 parts of sodium stearate are added, and the mixture is reacted at 80℃ for 1h, filtered and dried at 70-80℃, and then ground to obtain surface modified oyster shell powder;

[0053] S12, 100 parts of the surface modified oyster shell powder and 2.5 parts of silane coupling agent KH-550 are added into 500 parts of anhydrous ethanol, ultrasonic dispersion for 40 min, reaction at 80℃ for 24h, filtration and drying, and then calcination at 600℃ for 2h, and then 5 parts of wood powder and 10 parts of cellulose powder are ball milled for 30 min to obtain the modified filler.

[0054] The preparation method of the modified polyurethane emulsion of the embodiment comprises the following steps:

[0055] S21, by mass parts, 5 parts of isophorone diisocyanate is added to the reaction kettle, 15 parts of polyether diol-2000, 40 parts of rapeseed oil and 2 parts of dibutyl tin dilaurate are added, and reacted at 90℃ for 2h, 3 parts of 2, 2-dimethylol butyric acid and 2 parts of trimethylolpropane are added and reacted for 1h, the temperature is reduced to 60℃, 8 parts of hydroxyethyl methacrylate is added and reacted for 6h, and reduced to 50℃, 15 parts of triethylamine is added for neutralization, and rapeseed oil based waterborne polyurethane is prepared;

[0056] S22, by mass parts, 20 parts of rapeseed oil based waterborne polyurethane and 60 parts of deionized water are added to the emulsifier, and emulsified at high speed for 2h to obtain modified polyurethane emulsion.

[0057] The preparation method of the wear-resistant aid of the embodiment comprises the following steps:

[0058] S31, by mass parts, 1.4 parts of trimethylol aminomethyl methane is added to 300 parts of deionized water, 10wt% hydrochloric acid is added to adjust the pH to 8.5, and a buffer solution is prepared, 0.8 parts of o-dihydroxybenzene is dissolved in the buffer solution, 2 parts of hexagonal boron nitride powder with an average particle size of 15μm is added and ultrasonic dispersed for 2h, and reacted for 24h, and then filtered and dried at 50℃ to obtain modified hexagonal boron nitride;

[0059] S32, 2 parts of modified hexagonal boron nitride is added to 200 parts of N, N-dimethylformamide, ultrasonic dispersed, and then 2 parts of silicon carbide powder with an average particle size of 90nm is added, and reacted at 100℃ for 24h, and then filtered and dried to obtain the wear-resistant aid.

[0060] The preparation method of the high-strength PVC wood grain sheet of the embodiment comprises the following steps:

[0061] S1, the raw materials of the transparent layer, the color film layer and the substrate layer are weighed and added to the high-speed mixer respectively, and stirred at 2000rpm for 10min to prepare the mixed raw materials of the transparent layer, the color film layer and the substrate layer;

[0062] S2, the mixed raw materials of the transparent layer, the color film layer and the substrate layer are added to the calender respectively, the calendering temperature is 170℃, the calendering time is 30min, and the transparent layer, the color film layer and the substrate layer are calendered to the specified thickness;

[0063] S3, the photoinitiator is dissolved in 5 parts of methanol in the stirrer, and then the modified polyurethane emulsion, the dispersing agent and the wear-resistant aid are added to the stirrer to prepare the UV coating, the UV coating is applied on the transparent layer by the roll coater, the thickness of the coating is 100μm, and the UV coating is cured by ultraviolet light irradiation, and then the transparent layer, the color film layer and the substrate layer are stacked from top to bottom, and hot pressed for 30min to prepare the PVC wood grain sheet crude product;

[0064] S4, the PVC wood grain sheet crude product is cut into a specified size, and packaged to obtain the high-strength PVC wood grain sheet product.

[0065] Embodiment 2, refer to Figure 1 As shown in the figure, the high-strength PVC wood grain sheet of the embodiment is sequentially provided with a UV high-temperature resistant coating layer, a transparent layer, a color film layer and a substrate layer from top to bottom.

[0066] The UV high-temperature resistant coating layer includes the following raw materials by mass fraction: 70 parts of modified polyurethane emulsion, 3 parts of leveling agent, 4 parts of wear-resistant aid and 2 parts of photoinitiator.

[0067] The transparent layer includes the following raw materials by mass fraction: 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.

[0068] The color film layer includes the following raw materials by mass fraction: 100 parts of polyvinyl chloride resin, 20 parts of modified filler, 8 parts of color master batch, 25 parts of toughening agent, 20 parts of plasticizer, 1 part of stabilizer, 1 part of lubricant and 1 part of antioxidant.

[0069] The substrate layer includes the following raw materials by mass fraction: 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.

[0070] The thickness of the substrate 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.

[0071] The photoinitiator of the UV high-temperature resistant coating layer is a hydroxy ketone photoinitiator with a model number of 500, and the leveling agent is an organic silicon resin leveling agent with a model number of BYK-310.

[0072] The plasticizer of the transparent layer, the color film layer and the substrate layer is all diisononyl phthalate, the toughening agent is all MBS, the stabilizer is all stearylbenzoyl methane, the lubricant is a mixture of zinc stearate and calcium stearate with a mass ratio of 1:3, and the antioxidant is a mixture of 168 and 9228 with a mass ratio of 1:1.

[0073] The preparation method of the modified filler and the modified polyurethane emulsion of the embodiment is the same as that of Embodiment 1.

[0074] The difference between the wear-resistant aid of the 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.

[0075] The preparation method of the high-strength PVC wood grain sheet of the embodiment includes the following steps:

[0076] S1, the raw materials of the transparent layer, the color film layer and the substrate layer are weighed and added into a high-speed mixer respectively, stirred at 2500 rpm for 15 min to prepare the mixed raw materials of the transparent layer, the color film layer and the substrate layer;

[0077] S2, the mixed raw materials of the transparent layer, the color film layer and the substrate layer are added into a calender respectively, the calendering temperature is 175℃, the calendering time is 25 min, and the calendering is carried out to the specified thickness to prepare the transparent layer, the color film layer and the substrate layer;

[0078] S3, the photoinitiator is dissolved in 3 parts of ethanol in a blender, then the modified polyurethane emulsion, the dispersing agent and the wear-resistant auxiliary agent are added into the blender to prepare the UV coating, the UV coating is applied on the transparent layer by a roll coater, the thickness of the coating is 145μm, and after ultraviolet light irradiation curing, the transparent layer, the color film layer and the substrate layer are stacked from top to bottom and hot pressed for 30 min to prepare the PVC wood grain sheet crude product;

[0079] S4, the PVC wood grain sheet crude product is cut into a specified specification to prepare the high-strength PVC wood grain sheet product.

[0080] Embodiment 3, see Figure 1 The high-strength PVC wood grain sheet of the embodiment is provided with a UV high-temperature resistant coating, a transparent layer, a color film layer and a substrate layer from top to bottom;

[0081] The UV high-temperature resistant coating comprises the following raw materials by mass fraction: 70 parts of modified polyurethane emulsion, 3 parts of leveling agent, 4 parts of wear-resistant auxiliary agent and 2 parts of photoinitiator;

[0082] The transparent layer comprises the following raw materials by mass fraction: 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;

[0083] The color film layer comprises the following raw materials by mass fraction: 100 parts of polyvinyl chloride resin, 20 parts of modified filler, 8 parts of color master batch, 25 parts of toughening agent, 20 parts of plasticizer, 1 part of stabilizer, 1 part of lubricant and 1 part of antioxidant;

[0084] The substrate layer comprises the following raw materials by mass fraction: 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.

[0085] The thickness of the substrate layer is 3.5mm, the thickness of the transparent layer is 0.5mm, and the thickness of the high-strength PVC wood grain sheet is 5mm.

[0086] The photoinitiator of the UV high-temperature resistant coating is an alkyl phenone photoinitiator, and the model number is 2959; the leveling agent is a polyacrylate leveling agent, and the model number is BYK-390.

[0087] The plasticizer of the transparent layer, the color film layer and the substrate layer is all bisquintozan ester; the toughening agent is all PCL; the stabilizer is all dimethyl di-mercapto acetic acid isooctyl tin; the lubricant is all zinc stearate and calcium stearate mixed in a mass ratio of 1:3; the antioxidant is all 1098 and 9228 mixed in a mass ratio of 1:1.

[0088] The preparation method of the modified filler and the wear-resistant aid of the embodiment is the same as that of example 1.

[0089] The modified polyurethane emulsion of the embodiment is different from that of example 1 in that the catalyst is replaced by triethyl phosphine and the capping agent is replaced by caprolactam.

[0090] The preparation method of the high-strength PVC wood grain sheet of the embodiment comprises the following steps:

[0091] S1, the raw materials of the transparent layer, the color film layer and the substrate layer are weighed and added into a high-speed mixer respectively, and stirred at 3000 rpm for 5 min to prepare the mixed raw materials of the transparent layer, the color film layer and the substrate layer;

[0092] S2, the mixed raw materials of the transparent layer, the color film layer and the substrate layer are added into a calender respectively, the calendering temperature is 180℃, the calendering time is 35 min, and the transparent layer, the color film layer and the substrate layer are prepared by calendering to the specified thickness;

[0093] S3, the photoinitiator is dissolved in 5 parts of isopropyl alcohol in a stirrer, and then the modified polyurethane emulsion, the dispersing agent and the wear-resistant aid are added into the stirrer to prepare the UV coating. The UV coating is applied on the transparent layer by a roll coater, and the thickness of the coating is 60μm. After ultraviolet light irradiation and curing, the transparent layer, the color film layer and the substrate layer are stacked from top to bottom and hot-pressed for 20 min to prepare the PVC wood grain sheet crude product;

[0094] S4, the PVC wood grain sheet crude product is cut into a specified size, and packaged to prepare the high-strength PVC wood grain sheet product.

[0095] Comparative example 1, the difference between the comparative example 1 and example 1 is that the modified filler is directly ball-milled from unmodified oyster shell powder, wood powder and cellulose powder.

[0096] Comparative example 2, the difference between the comparative example 2 and example 1 is that the raw material polyether diol-2000 of the modified polyurethane emulsion is replaced by polyether diol-6000.

[0097] Comparative example 3, the difference between the comparative example 3 and example 1 is that the wear-resistant aid is replaced by aluminum oxide powder.

[0098] Performance test

[0099] The surface hardness of the PVC wood grain sheets prepared from each example and the comparative example was tested according to GB / T 6739-2006 "Paints and varnishes - Determination of film hardness by pencil test".

[0100] The wear rate of the PVC wood grain sheets prepared from each example and the comparative example was tested according to GB3960-83 "Plastics - Determination of the wear resistance by sliding abrasion".

[0101] The tensile strength and elongation at break of the PVC wood grain sheets prepared from each example and the comparative example were tested according to GB / T 1040.2-2022 "Plastics - Determination of the tensile properties - Part 2: test conditions for moulded and extruded plastics".

[0102] The notched impact strength of the PVC wood grain sheets prepared from each example and the comparative example was tested according to GB / T1843-2008 "Plastics - Determination of the Izod Charpy impact strength".

[0103] The test results are shown in Table 1 below:

[0104] Table 1 Performance test results

[0105]

[0106] According to the data in the above table, the surface hardness of the PVC wood grain sheets prepared from Examples 1 to 3 is 3H, and the wear rate is 0.06 g / 100r, indicating that the PVC wood grain sheets prepared by the present application have excellent wear resistance; the tensile strength of the PVC wood grain sheets prepared from Examples 1 to 3 is between 46.3 and 46.4 MPa, the elongation at break is between 53.9 and 54.3%, and the notched impact strength is between 9.3 and 9.6 kJ / m 2 2, indicating that the PVC wood grain sheets prepared by the present application have excellent impact resistance and high strength.

[0107] The above description is only a preferred specific embodiment of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can make equivalent substitutions or changes to the technical solutions and inventive concepts of the present application within the technical scope disclosed by the present application, which should be covered within the protection scope of the present application.

[0108] The preferred embodiments of the application disclosed above are only to facilitate the elucidation of the application. The preferred embodiments do not describe all the details of the application and limit the application to the specific embodiments. Obviously, many modifications and variations can be made in light of the teachings above. The description is chosen and described in order to provide the best illustration of the application and its practical application to those skilled in the art and to enable those skilled in the art to best utilize the application. The application is limited only by the claims and their full scope and equivalents.

Claims

1. High-strength PVC wood grain sheet, characterized in that, The layers are arranged from top to bottom as follows: UV high-temperature resistant coating, transparent layer, color film layer, and substrate layer. The UV high-temperature resistant coating, by weight, includes the following raw materials: 60-80 parts modified polyurethane emulsion, 2-3 parts leveling agent, 1-5 parts abrasion resistant agent, and 2-5 parts photoinitiator; The transparent layer, by weight, comprises the following raw materials: 80-100 parts polyvinyl chloride resin, 20-60 parts modified filler, 20-30 parts toughening agent, 20-60 parts plasticizer, 0.5-2 parts stabilizer, 0.5-2 parts lubricant, and 0.1-1 parts antioxidant; The color filter layer, by weight, includes the following raw materials: 80-100 parts polyvinyl chloride resin, 20-60 parts modified filler, 8-15 parts color masterbatch, 20-30 parts toughening agent, 20-60 parts plasticizer, 0.5-2 parts stabilizer, 0.5-2 parts lubricant, and 0.1-1 parts antioxidant; The substrate layer, by weight, includes the following raw materials: 80-100 parts polyvinyl chloride resin, 80-100 parts modified filler, 20-30 parts toughening agent, 20-60 parts plasticizer, 0.5-2 parts stabilizer, 0.5-2 parts lubricant, and 0.1-1 parts antioxidant; The method for preparing the modified polyurethane emulsion includes the following steps: S21. By weight, add 3-5 parts of isophorone diisocyanate to a reaction vessel, add 10-20 parts of polyether diol, 30-40 parts of rapeseed oil and 0.5-2 parts of catalyst, and react at 80-90℃ for 2-3 hours. Add 3-5 parts of 2,2-dimethylolbutyric acid and 2-4 parts of trimethylolpropane and react for 1-2 hours. Reduce the temperature to 60-70℃, add 5-10 parts of end-capping agent and react for 6-8 hours. Reduce the temperature to 40-50℃ and add 10-15 parts of triethylamine to neutralize, thus obtaining rapeseed oil-based waterborne polyurethane. S22. By weight, add 20-30 parts of rapeseed oil-based waterborne polyurethane and 50-60 parts of deionized water to an emulsifier, and emulsify at high speed for 1-2 hours to obtain a modified polyurethane emulsion. The preparation method of the wear-resistant additive includes the following steps: S31. According to the mass fraction, add 1.4 parts of tris(hydroxymethyl)aminomethane to 250-300 parts of deionized water, add 5-10 wt% 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, sonicate for 1-2 h, react for 18-24 h, filter and dry at 50-60℃ to obtain modified hexagonal boron nitride; S32. Add 1-2 parts of modified hexagonal boron nitride to 200-300 parts of N,N-dimethylformamide, disperse by ultrasonication, and then add 1-2 parts of silicon carbide powder with an average particle size of 50-100nm. React at 90-110℃ for 12-24h, filter and dry to obtain wear-resistant additive.

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

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 benzophenone, hydroxy ketone, and alkyl phenyl ketone; the leveling agent is one or more combinations of cellulose acetate butyrate, silicone resin, and polyacrylate.

4. The high-strength PVC wood grain sheet according to claim 1, characterized in that, The plasticizers of the transparent layer, color filter layer, and substrate layer are all one or more combinations of diisononyl phthalate, epoxidized 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, stearoyl 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 method for preparing the modified filler includes the following steps: S11. By weight, 50-100 parts of oyster shell powder are passed through a 300-400 mesh sieve, added to 100-200 parts of deionized water, ultrasonically dispersed, and then 0.3-0.5 parts of sodium hydroxide and 0.5-2 parts of sodium stearate are added. The mixture is reacted at 75-80℃ for 0.5-1.5 hours, filtered, dried at 70-80℃, and ground to obtain surface-modified oyster shell powder. S12. By weight, 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, sonicate for 30-40 minutes, react at 70-80℃ for 24-36 hours, filter and dry, calcine at 500-600℃ for 2-3 hours, add 5-10 parts of wood flour and 10-20 parts of cellulose powder, ball mill for 30-40 minutes to obtain the modified filler.

6. The high-strength PVC wood grain sheet according to claim 1, characterized in that, The catalyst in S21 is one or more of dibutyltin dilaurate, triethylphosphine, and diethyltin octanoate, and the end-capping agent is one or more of hydroxyethyl methacrylate, caprolactam, and hydroxypropyl acrylate.

7. The method for preparing high-strength PVC wood grain sheets according to any one of claims 1-6, characterized in that, Includes the following steps: S1. Weigh the raw materials of the transparent layer, color filter layer and substrate layer, and add them separately into a high-speed mixer. Stir and premix at 2000~3000 rpm for 5~15 minutes to obtain the mixed raw materials of the transparent layer, color filter layer and substrate layer. S2. Add the mixed raw materials of the transparent layer, color filter layer and substrate layer to a calender and calender them to the specified thickness to obtain the transparent layer, color filter layer and substrate layer. S3. Dissolve the photoinitiator in 3-5 parts of organic solvent in a mixer, then premix the modified polyurethane emulsion, dispersant, and wear-resistant additive in the mixer to obtain a UV coating. Apply the UV coating to the transparent layer using a roller coater. After curing by UV irradiation, stack the transparent layer, color film layer, and substrate layer from top to bottom and hot press for 20-30 minutes to obtain a rough PVC wood grain sheet. S4. Cut the crude PVC wood grain sheet into specified specifications and package it to obtain high-strength PVC wood grain sheet products.

8. The method for preparing high-strength PVC wood grain sheets according to claim 7, characterized in that, The calendering temperature of the calender in S2 is 160~180℃, and the calendering time is 20~40min; the organic solvent in S3 is one or more combinations of methanol, ethanol, and isopropanol, and the thickness of the UV coating is 50~150μm.

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