Production process of WPC mould pressing floor

Abstract

The invention relates to the technical field of mould pressing floors, in particular to a WPC mould pressing floor production process which sequentially comprises the steps of raw material pretreatment, blending granulation, extrusion molding, hot-pressing shaping, surface treatment, cooling cutting, post-treatment and quality detection. On the basis of the prior art, a raw material formula and a preparation process are further improved, and the performance of the WPC mould pressing floor is remarkably improved, specifically, in the aspect of raw material functions, polyvinyl chloride resin serves as a base material, and basic forming performance and mechanical strength are provided for the floor; the calcium carbonate filler can increase the hardness and dimensional stability of the floor and reduce the production cost; the attapulgite powder endows the floor with natural texture and texture. A multifunctional interface layer is formed on the surface of the attapulgite powder subjected to special treatment and secondary modification, so that the compatibility and binding force with polyvinyl chloride resin are greatly improved.

Description

Technical Field

[0001] The invention relates to the technical field of molded floors, in particular to a production process of WPC molded floors. Background Art

[0002] WPC (Wood-Plastic Composite) molded flooring is a new type of environmentally friendly flooring material made of polyvinyl chloride (PVC) resin as the matrix, filled with attapulgite powder, calcium carbonate and other materials through a molding process.

[0003] Because WPC molded flooring combines the natural texture of wood with the durability of plastic, it is widely used in home decoration, commercial venues, public buildings, and other fields. In home decoration, WPC molded flooring's widespread use is mainly due to its easier cleaning and maintenance. In commercial venues such as shopping malls and hotels, its wear and scratch resistance meet the needs of these places. In public buildings such as schools and hospitals, WPC molded flooring's environmental friendliness and anti-slip properties help ensure the safety and health of personnel. However, the existing WPC molded floor production technology has many technical defects. At the raw material level, the bonding performance of attapulgite powder with matrix materials such as polyvinyl chloride resin is poor, resulting in an unstable internal structure of the floor, prone to problems such as delamination and cracking. The surface of attapulgite powder is highly polar and has poor compatibility with non-polar polyvinyl chloride resin, making it difficult for the two to form a strong interface bond. In terms of production technology, traditional processes are prone to causing problems such as floor size deviation and poor surface flatness. In terms of product performance, the wear resistance, surface hardness and other properties of existing WPC molded floors are difficult to meet the needs of high-end application scenarios.

[0004] As people's requirements for product quality increase, higher standards are put forward for the comprehensive performance of flooring. Flooring produced by traditional technology has gradually been unable to meet the needs of market development. The production process of a WPC molded floor proposed in the present invention is intended to solve the above technical defects. Summary of the Invention

[0005] In view of the problems existing in the prior art, the present invention provides a production process of a WPC molded floor.

[0006] To achieve the above object, the present invention provides the following technical solutions: A production process for WPC molded flooring, comprising the steps of raw material pretreatment, blending and granulation, extrusion molding, hot pressing and shaping, surface treatment, cooling and cutting, post-processing and quality inspection; The raw material pretreatment step comprises: weighing and mixing polyvinyl chloride resin, calcium carbonate, attapulgite powder, dioctyl phthalate, calcium zinc composite stabilizer, and stearic acid in proportion; The blending and granulation step comprises: mixing the raw materials in the pretreatment step in a high-speed mixer and a low-speed mixer in sequence, and then granulating the raw materials through a twin-screw extruder; The extrusion molding step comprises: extruding the granulated material through a single-screw extruder and molding it into a floor substrate through a mold; The hot pressing shaping step comprises: hot pressing and laminating the floor substrate, the printed color film decorative layer, and the PVC wear-resistant layer in a hot press; The surface treatment steps are: sequentially performing UV coating and embossing treatment; The cooling and cutting step comprises: cooling by a combination of air cooling and water cooling, and then cutting according to the specification size using a cutting machine; The post-processing step is: placing the cut floor in a constant temperature and humidity environment for aging; The quality inspection steps are as follows: inspecting the flooring and packaging and warehousing the flooring after it passes the inspection; Among them, after the blending and granulation step, a preforming step is set, and the blended and granulated materials are pre-pressed through a preforming mold to form floor blanks; after the surface treatment step, a surface hardening treatment step is added, and the floor is immersed in a hardening liquid containing nano-silica to improve the surface hardness.

[0007] As a further technical solution, the raw material pretreatment step is: polyvinyl chloride resin, calcium carbonate, attapulgite powder, dioctyl phthalate, calcium zinc composite stabilizer, and stearic acid are weighed and proportioned in a mass ratio of 30-40:40-50:5-10:5-8:2-4:1-3, wherein the K value of the polyvinyl chloride resin is 60-65.

[0008] As a further technical solution, the attapulgite powder needs to be soaked in a silane coupling agent ethanol solution with a concentration of 3-5wt% for 2-3 hours. The silane coupling agent is γ-methacryloxypropyltrimethoxysilane. After soaking, it is taken out and dried at 80-90°C to a moisture content of less than 1%, and then crushed to a particle size of 80-120 mesh by a jet mill. Finally, it is graded and screened by a vibrating screen to obtain a modified attapulgite powder exceeding 80 mesh for standby use.

[0009] As a further technical solution, the once-modified attapulgite powder is subjected to a secondary modification: the once-modified attapulgite powder is placed in a dopamine hydrochloride Tris-HCl buffer solution with a concentration of 2-4wt%, stirred and reacted at room temperature for 12-15 hours, washed with deionized water multiple times until neutral after the reaction, and then vacuum-dried at 60-70°C for 8-10 hours. The dried attapulgite powder is then subjected to plasma treatment, with a plasma treatment power of 80-100W, a treatment time of 3-5 minutes, and a treatment gas of neon. A multifunctional interface layer is formed on the surface of the attapulgite powder through dopamine self-polymerization and plasma treatment, thereby further improving the binding performance of the attapulgite powder with other raw materials. The pH of the dopamine hydrochloride Tris-HCl buffer solution is 8.5-8.8. As a further technical solution, the blending and granulation step is as follows: the mixing conditions of the high-speed mixer are 800-1000r / min, the temperature is raised to 110-120°C, and the mixing is carried out for 5-8min; the mixing conditions of the low-speed mixer are 200-300r / min, the temperature is reduced to 40-50°C, and the mixing is carried out for 3-5min; the temperature of the first zone of the twin-screw extruder is 160-170°C, the temperature of the second zone is 170-180°C, the temperature of the third zone is 180-190°C, the temperature of the fourth zone is 190-200°C, the temperature of the fifth zone is 200-210°C, the head temperature is 200-205°C, and the screw speed is 180-220r / min. As a further technical solution, in the extrusion molding step, the temperature of the feeding section of the single-screw extruder is 160-170°C, the temperature of the compression section is 170-180°C, the temperature of the metering section is 180-190°C, the temperature of the die head is 190-200°C, and the extrusion speed is 15-20m / min. As a further technical solution, in the hot pressing shaping step, the hot pressing temperature is increased from room temperature to 150-158°C at a heating rate of 5-8°C / min, the pressure is 8-10MPa, the holding time is 10-12min, and after the holding time is completed, the temperature is lowered to room temperature at a cooling rate of 6-8°C / min. As a further technical solution, the surface treatment step is as follows: the UV coating is applied by flow coating, the coating thickness is controlled at 0.08-0.12 mm, the UV paint used is polyurethane acrylate UV paint, the ultraviolet lamp power in the UV curing machine is 120-150 W, the curing temperature is 75-80 ° C, and the curing speed is 8-12 m / min; during embossing treatment, the embossing roller temperature is 120-130 ° C, the pressure is 3-5 MPa, the embossing roller pattern depth is 0.1-0.3 mm, the embossing speed matches the extrusion speed, and the error does not exceed ± 3%. As a further technical solution, in the cooling cutting step, the air cooling speed is 8-12 m / s, the water cooling temperature is 15-20° C., and the cutting accuracy is controlled within ±0.2 mm. As a further technical solution, in the preforming step, the pre-pressing pressure is 3-5 MPa, the temperature is 130-136°C, and the pre-pressing time is 1-2 min; In the surface hardening treatment step, the hardening liquid containing nano-silica is composed of 5-5.8% nano-silica by mass, 2-2.5% silane coupling agent KH570, 0.7-0.8% dispersant sodium polyacrylate, and the balance deionized water, and the average particle size of the nano-silica is 20-30nm. The hardening liquid is prepared by stirring evenly, the immersion time is 15-20 minutes, and the hardening liquid temperature is 40-50°C.

[0010] Compared with the prior art, the present invention has the following beneficial effects: The present invention significantly improves the performance of WPC molded flooring by further improving the raw material formula and preparation process based on the existing technology, as follows: In terms of raw material functionality, this invention uses polyvinyl chloride (PVC) resin as the matrix material, providing the floor with basic molding properties and mechanical strength. The calcium carbonate filler increases the floor's hardness and dimensional stability, reducing production costs. The attapulgite powder, after primary and secondary modification, forms a multifunctional interface layer on its surface, significantly improving its compatibility and bonding with PVC resin. Treatment with a silane coupling agent grafts organic groups onto the attapulgite powder's surface, reducing its surface polarity and enhancing its affinity with PVC resin. Dopamine self-polymerization and plasma treatment further introduce active groups onto the attapulgite powder's surface, forming a dense interface layer. This allows for a tighter bond between the attapulgite powder and PVC resin during blending, improving the overall mechanical properties of the floor. Dioctyl phthalate (DOP) acts as a plasticizer to lower the melting temperature and melt viscosity of polyvinyl chloride resin, thereby improving its flexibility and processing performance; calcium-zinc composite stabilizer improves the thermal stability of polyvinyl chloride resin and prevents decomposition during processing; stearic acid acts as a lubricant to reduce friction during processing and improve fluidity. During the co-blending and granulation process, strictly controlled mixing conditions, extrusion temperature, and speed ensure thorough and uniform mixing of all raw materials, forming a stable material system and laying the foundation for subsequent molding. High-speed mixing rapidly heats the materials and achieves initial dispersion, while low-speed mixing cools the materials and ensures more uniform mixing. The temperature gradient setting of the twin-screw extruder ensures that the materials reach optimal melting and plasticization states at different stages. Precisely controlled temperature and speed during extrusion molding ensure the dimensional accuracy and surface quality of the flooring substrate. During the hot pressing process, precise control of temperature, pressure, and time ensures a secure bond between the flooring substrate, the decorative layer, and the wear-resistant layer, forming a stable layered structure and enhancing the overall strength and wear resistance of the flooring. During the surface treatment step, UV coating and embossing further enhance the performance of the floor. The wear-resistant and stain-resistant coating formed by UV coating protects the floor surface and extends its service life; the embossing treatment gives the floor a unique texture and texture, while increasing surface friction and improving anti-slip performance. The combination of air cooling and water cooling for cooling cutting quickly and evenly reduces the temperature of the floor, prevents deformation due to temperature changes, and ensures cutting accuracy. The pre-forming step allows the material to be initially formed, reducing the pressure and time of subsequent hot pressing and shaping, improving production efficiency, and making the internal structure of the floor denser. The surface hardening treatment is achieved by impregnation with a hardening liquid containing nano-silica. Nano-silica fills the pores on the surface of the floor and, under the action of silane coupling agents and dispersants, forms a firm bond with the surface of the floor, significantly improving surface hardness and wear resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a histogram of the wear resistance test of the present invention. DETAILED DESCRIPTION

[0012] The following is a clear and complete description of 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 them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0013] The invention provides a production process of WPC molded floor, which sequentially comprises the steps of raw material pretreatment, blending and granulation, extrusion molding, hot pressing and shaping, surface treatment, cooling and cutting, post-processing and quality inspection.

[0014] In the raw material pretreatment step, polyvinyl chloride resin, calcium carbonate, attapulgite powder, dioctyl phthalate, calcium zinc composite stabilizer, and stearic acid are weighed and proportioned in proportion. Specifically, polyvinyl chloride resin, calcium carbonate, attapulgite powder, dioctyl phthalate, calcium zinc composite stabilizer, and stearic acid are weighed and proportioned in a mass ratio of 30-40:40-50:5-10:5-8:2-4:1-3, wherein the polyvinyl chloride resin K value is 60-65. The attapulgite powder is first soaked in an ethanol solution of a silane coupling agent having a concentration of 3-5wt% for 2-3h. The silane coupling agent is selected from gamma-methacryloxypropyltrimethoxysilane. After soaking, it is taken out and dried at 80-90°C to a water content of less than 1%, and then crushed to a particle size of 80-120 mesh by a jet mill. Finally, it is graded and screened by a vibrating screen to obtain a modified attapulgite powder over 80 mesh for standby use. The primary modified attapulgite powder is subjected to secondary modification: the primary modified attapulgite powder is placed in a dopamine hydrochloride Tris-HCl buffer solution (pH=8.5-8.8) with a concentration of 2-4wt%, stirred and reacted at room temperature for 12-15h, and after the reaction is completed, washed with deionized water multiple times until neutral, and then vacuum dried at 60-70°C for 8-10h. The dried attapulgite powder is then subjected to plasma treatment, with a plasma treatment power of 80-100W, a treatment time of 3-5min, and neon as the treatment gas.

[0015] In the blending and granulation step, the raw materials from the pretreatment step are sequentially mixed in a high-speed mixer and a low-speed mixer, and then granulated through a twin-screw extruder. The mixing conditions for the high-speed mixer are 800-1000 r / min, the temperature is raised to 110-120°C, and the mixing is carried out for 5-8 minutes; the mixing conditions for the low-speed mixer are 200-300 r / min, the temperature is reduced to 40-50°C, and the mixing is carried out for 3-5 minutes. The temperature of the twin-screw extruder zone 1 is 160-170°C, the temperature of zone 2 is 170-180°C, the temperature of zone 3 is 180-190°C, the temperature of zone 4 is 190-200°C, and the temperature of zone 5 is 200-210°C. The head temperature is 200-205°C, and the screw speed is 180-220 r / min.

[0016] In the extrusion step, the granulated material is extruded through a single-screw extruder and formed into a flooring substrate through a die. The single-screw extruder has a feed section temperature of 160-170°C, a compression section temperature of 170-180°C, a metering section temperature of 180-190°C, and a die head temperature of 190-200°C. The extrusion speed is 15-20 m / min.

[0017] During the hot-pressing step, the flooring substrate, printed color film decorative layer, and PVC wear-resistant layer are laminated in a hot press. The hot-pressing temperature is raised from room temperature to 150-158°C at a rate of 5-8°C / min, with a pressure of 8-10 MPa. The pressure is maintained for 10-12 minutes, and then cooled to room temperature at a rate of 6-8°C / min.

[0018] The surface treatment steps include UV coating and embossing. The UV coating is applied by curtain coating, with a coating thickness of 0.08-0.12mm. The UV paint used is a polyurethane acrylate UV paint. The UV lamp power of the UV curing machine is 120-150W, the curing temperature is 75-80°C, and the curing speed is 8-12m / min. During the embossing process, the embossing roller temperature is 120-130°C, the pressure is 3-5MPa, and the embossing roller pattern depth is 0.1-0.3mm.

[0019] UV paint is purchased from Allnex: Ebecryl 8807 aliphatic polyurethane acrylate UV light curing resin.

[0020] During the cooling and cutting step, after cooling by a combination of air and water cooling, the pieces are cut to size using a cutting machine. The air cooling speed is 8-12m / s and the water cooling temperature is 15-20℃.

[0021] After the blending and granulation step, a pre-forming step is provided, wherein the blended and granulated materials are pre-pressed through a pre-forming mold to form flooring blanks. The pre-pressing pressure is 3-5 MPa, the temperature is 130-136°C, and the pre-pressing time is 1-2 minutes.

[0022] After the surface treatment step, a surface hardening treatment step is added, in which the floor is immersed in a hardening liquid containing nano-silica to increase the surface hardness. The hardening liquid containing nano-silica is composed of 5-5.8% nano-silica by mass, 2-2.5% silane coupling agent KH570, 0.7-0.8% dispersant sodium polyacrylate, and the balance deionized water. The nano-silica has an average particle size of 20-30nm and is prepared by stirring. The immersion time is 15-20 minutes and the hardening liquid temperature is 40-50°C.

[0023] In the post-processing step, the cut floor is placed in a constant temperature and humidity environment for aging.

[0024] The quality inspection step is to inspect the floor. The inspection items include appearance, dimensional accuracy, wear resistance, fire resistance, etc. After passing the inspection, the floor will be packaged and put into storage.

[0025] The raw materials and equipment used in the following examples were all commercially available or homemade. The calcium-zinc composite stabilizer was purchased from Shandong Ruifeng Polymer, RF-CZ100. Example 1

[0026] Raw material pretreatment: Weigh 30 parts polyvinyl chloride resin (K value 60), 40 parts calcium carbonate, 5 parts attapulgite powder, 5 parts dioctyl phthalate, 2 parts calcium-zinc composite stabilizer, and 1 part stearic acid. The attapulgite powder was soaked in a 3 wt% ethanol solution of γ-methacryloxypropyltrimethoxysilane for 2 hours. After soaking, it was dried at 80°C until the moisture content was less than 1%. It was then ground to 80 mesh using a jet mill and sieved through a vibrating sieve. The sieved attapulgite powder was then placed in a 2 wt% dopamine hydrochloride Tris-HCl buffer solution (pH = 8.5). The mixture was stirred at room temperature for 12 hours, washed with deionized water until neutral, and vacuum-dried at 60°C for 8 hours. The powder was then treated with neon plasma at 80 W for 3 minutes.

[0027] Blending and granulation: The pretreated raw materials were placed in a high-speed mixer and mixed at 800 r / min. The temperature was raised to 110°C and mixed for 5 minutes. Then, the raw materials were transferred to a low-speed mixer and mixed at 200 r / min. The temperature was lowered to 40°C and mixed for 3 minutes. The raw materials were then granulated through a twin-screw extruder with the temperatures of 160°C in zone 1, 170°C in zone 2, 180°C in zone 3, 190°C in zone 4, and 200°C in zone 5. The die head temperature was 200°C and the screw speed was 180 r / min.

[0028] Extrusion molding: The granulated material is extruded through a single-screw extruder with a feed section temperature of 160°C, a compression section temperature of 170°C, a metering section temperature of 180°C, a die head temperature of 190°C, and an extrusion speed of 15m / min to form a floor substrate.

[0029] Preforming: The blended and granulated materials are pre-pressed through a pre-forming mold with a pre-pressing pressure of 3 MPa, a temperature of 130°C, and a pre-pressing time of 1 minute to form floor blanks.

[0030] Hot pressing and shaping: The floor blank is hot-pressed with the printed color film decorative layer and the PVC wear-resistant layer in a hot press. The hot pressing temperature is increased from room temperature to 150°C at a rate of 5°C / min, the pressure is 8MPa, and the holding time is 10min. After the holding time is completed, the temperature is lowered to room temperature at a rate of 6°C / min.

[0031] Surface treatment: UV coating is applied by flow coating, the coating thickness is controlled at 0.08mm, the UV paint used is polyurethane acrylate UV paint, the ultraviolet lamp power in the UV curing machine is 120W, the curing temperature is 75℃, and the curing speed is 8m / min; during embossing treatment, the embossing roller temperature is 120℃, the pressure is 3MPa, and the embossing roller pattern depth is 0.1mm.

[0032] Surface Hardening: Prepare a hardening solution containing 5% nano-silica, 2% silane coupling agent KH570, 0.7% sodium polyacrylate dispersant, and the balance deionized water. The average nano-silica particle size should be 20 nm. Stir thoroughly. Immerse the floor in the hardening solution for 15 minutes at 40°C.

[0033] Cooling cutting: After cooling by a combination of air cooling (wind speed 8m / s) and water cooling (temperature 15℃), the product is cut into size using a cutting machine.

[0034] Post-processing: Place the cut floor in a constant temperature and humidity environment with a temperature of 25°C and a relative humidity of 50% for aging.

[0035] Quality inspection: The floor will be inspected for appearance, dimensional accuracy, wear resistance, fire resistance, etc., and will be packaged and stored after passing the inspection. Example 2

[0036] Raw material pretreatment: Weigh 35 parts polyvinyl chloride resin (K value 63), 45 parts calcium carbonate, 7 parts attapulgite powder, 6 parts dioctyl phthalate, 3 parts calcium-zinc composite stabilizer, and 2 parts stearic acid. The attapulgite powder was treated as in Example 1, except that it was immersed in a silane coupling agent ethanol solution at a concentration of 4 wt% for 2.5 hours and then crushed to 100 mesh. A dopamine hydrochloride Tris-HCl buffer solution was prepared at a concentration of 3 wt% and a pH of 8.6. The reaction time was 13 hours, the vacuum drying temperature was 65°C, and the plasma treatment power was 90 W for 4 minutes.

[0037] Blending and granulation: The high-speed mixer was mixed at 900 r / min, the temperature was raised to 115°C, and the mixing was continued for 6 minutes. The low-speed mixer was mixed at 250 r / min, the temperature was lowered to 45°C, and the mixing was continued for 4 minutes. The twin-screw extruder temperature was 165°C in zone 1, 175°C in zone 2, 185°C in zone 3, 195°C in zone 4, and 205°C in zone 5. The die head temperature was 203°C, and the screw speed was 200 r / min.

[0038] Extrusion molding: single-screw extruder feeding section temperature 165℃, compression section temperature 175℃, metering section temperature 185℃, die head temperature 195℃, extrusion speed 17m / min.

[0039] Preforming: pre-pressing pressure 4 MPa, temperature 133°C, pre-pressing time 1.5 min.

[0040] Hot pressing: the hot pressing temperature is increased from room temperature to 154°C at a rate of 6°C / min, the pressure is 9 MPa, the holding time is 11 min, and the cooling rate is 7°C / min.

[0041] Surface treatment: UV coating thickness 0.1mm, UV lamp power 130W, curing temperature 77℃, curing speed 10m / min; embossing roller temperature 125℃, pressure 4MPa, pattern depth 0.2mm.

[0042] Surface hardening treatment: the mass fraction of nano-silica in the hardening liquid is 5.4%, the mass fraction of silane coupling agent KH570 is 2.2%, the mass fraction of dispersant sodium polyacrylate is 0.75%, the average particle size of nano-silica is 25nm, the immersion time is 17min, and the hardening liquid temperature is 45℃.

[0043] Cooling cutting: air cooling speed 10m / s, water cooling temperature 17℃.

[0044] Post-processing and quality inspection: same as Example 1. Example 3

[0045] Raw material pretreatment: Weigh 40 parts polyvinyl chloride resin (K value 65), 50 parts calcium carbonate, 10 parts attapulgite powder, 8 parts dioctyl phthalate, 4 parts calcium-zinc composite stabilizer, and 3 parts stearic acid. Soak the attapulgite powder in a 5wt% ethanol solution of silane coupling agent for 3 hours and then grind it to 120 mesh size. A 4wt% Tris-HCl buffer solution of dopamine hydrochloride (pH 8.8) was added. The reaction time was 15 hours. The vacuum drying temperature was 70°C, and the plasma treatment power was 100W for 5 minutes.

[0046] Blending and granulation: High-speed mixer at 1000 r / min, temperature raised to 120°C, mixing for 8 minutes; low-speed mixer at 300 r / min, temperature lowered to 50°C, mixing for 5 minutes. Twin-screw extruder: Zone 1 temperature 170°C, Zone 2 temperature 180°C, Zone 3 temperature 190°C, Zone 4 temperature 200°C, Zone 5 temperature 210°C, die head temperature 205°C, screw speed 220 r / min.

[0047] Extrusion molding: single-screw extruder feeding section temperature 170℃, compression section temperature 180℃, metering section temperature 190℃, die head temperature 200℃, extrusion speed 20m / min.

[0048] Preforming: pre-pressing pressure 5 MPa, temperature 136°C, pre-pressing time 2 min.

[0049] Hot pressing: the hot pressing temperature is increased from room temperature to 158°C at a rate of 8°C / min, the pressure is 10 MPa, the holding time is 12 min, and the cooling rate is 8°C / min.

[0050] Surface treatment: UV coating thickness 0.12mm, UV lamp power 150W, curing temperature 80℃, curing speed 12m / min; embossing roller temperature 130℃, pressure 5MPa, pattern depth 0.3mm.

[0051] Surface hardening treatment: the mass fraction of nano-silica in the hardening liquid is 5.8%, the mass fraction of silane coupling agent KH570 is 2.5%, the mass fraction of dispersant sodium polyacrylate is 0.8%, the average particle size of nano-silica is 30nm, the immersion time is 20min, and the hardening liquid temperature is 50℃.

[0052] Cooling cutting: air cooling speed 12m / s, water cooling temperature 20℃.

[0053] Post-processing and quality inspection: same as Example 1.

[0054] Comparative Example 1 The WPC molded floor was prepared in the same manner as in Example 1, except that the attapulgite powder was not soaked in a silane coupling agent or subjected to secondary modification in the raw material pretreatment step, and the original attapulgite powder was used directly.

[0055] Raw material pretreatment: 30 parts of polyvinyl chloride resin (K value 60), 40 parts of calcium carbonate, 5 parts of attapulgite powder, 5 parts of dioctyl phthalate, 2 parts of calcium zinc composite stabilizer, and 1 part of stearic acid were weighed. The attapulgite powder was not pretreated.

[0056] The subsequent steps: blending and granulation, extrusion molding, preforming, hot pressing and shaping, surface treatment, surface hardening treatment, cooling and cutting, post-processing, and quality inspection are all the same as those in Example 1.

[0057] Comparative Example 2 A WPC molded floor was prepared in the same manner as in Example 1, except that no surface hardening treatment was performed.

[0058] Comparative Example 3 A WPC molded floor was prepared in the same manner as in Example 1, except that no preforming treatment was performed.

[0059] Performance Testing Wear resistance test The floors of the examples and comparative examples were tested with reference to GB / T1768-2006 "Determination of abrasion resistance of paints and varnishes - Rotating rubber grinding wheel method". The abrasion revolutions were set to 2000 revolutions, and the abrasion loss was recorded. The test results are as follows: Table 1

[0060] It can be seen from the test results in Table 1 that the wear resistance of the floor prepared in the embodiment of the present invention is greatly improved.

[0061] Surface hardness test The surface hardness of the floors of the embodiment and the comparative example was tested with reference to GB / T6739-2017 "Determination of Film Hardness of Paints and Varnishes by Pencil Method". The pencil hardness test method was used to record the hardness grades. The test results are as follows: Table 2

[0062] It can be seen from Table 2 that the floor surface prepared in the embodiment of the present invention has higher hardness. The improvement of hardness can further broaden the application field and service life of the floor.

[0063] Dimensional stability test The floor samples of the embodiment and the comparative example were placed in an environment with a temperature of 50°C and a relative humidity of 80% for 7 days, and the length, width and thickness change rates of the floor were measured. The test results are as follows: Table 3

[0064] It can be seen from Table 3 that the flooring prepared in the embodiment of the present invention has excellent dimensional stability.

[0065] The preferred embodiments of the present invention disclosed above are intended only to help illustrate the present invention. The preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific embodiments described. Obviously, many modifications and variations are possible based on the content of this specification.

Claims

1. A production process for WPC molded flooring, characterized in that: The following steps are included in sequence: Raw material pretreatment, blending and granulation, extrusion molding, hot pressing and shaping, surface treatment, cooling and cutting, post-processing and quality inspection steps; The raw material pretreatment step comprises: weighing and mixing polyvinyl chloride resin, calcium carbonate, attapulgite powder, dioctyl phthalate, calcium zinc composite stabilizer, and stearic acid in proportion; The blending and granulation step comprises: mixing the raw materials in the pretreatment step in a high-speed mixer and a low-speed mixer in sequence, and then granulating the raw materials through a twin-screw extruder; The extrusion molding step comprises: extruding the granulated material through a single-screw extruder and molding it into a floor substrate through a mold; The hot pressing shaping step comprises: hot pressing and laminating the floor substrate, the printed color film decorative layer, and the PVC wear-resistant layer in a hot press; The surface treatment steps are: sequentially performing UV coating and embossing treatment; The cooling and cutting step comprises: cooling by a combination of air cooling and water cooling, and then cutting according to the specification size using a cutting machine; The post-processing step is: placing the cut floor in a constant temperature and humidity environment for aging; The quality inspection steps are as follows: inspecting the flooring and packaging and warehousing the flooring after it passes the inspection; Among them, after the blending and granulation step, a preforming step is set, and the blended and granulated materials are pre-pressed through a preforming mold to form floor blanks; after the surface treatment step, a surface hardening treatment step is added, and the floor is immersed in a hardening liquid containing nano-silica to improve the surface hardness.

2. The production process of WPC molded floor according to claim 1, characterized in that: The raw material pretreatment step comprises: weighing and mixing polyvinyl chloride resin, calcium carbonate, attapulgite powder, dioctyl phthalate, calcium zinc composite stabilizer, and stearic acid in a mass ratio of 30-40:40-50:5-10:5-8:2-4:1-3, wherein the K value of the polyvinyl chloride resin is 60-65.

3. The production process of WPC molded floor according to claim 2, characterized in that: The attapulgite powder is first soaked in a silane coupling agent ethanol solution with a concentration of 3-5wt% for 2-3 hours, where the silane coupling agent is γ-methacryloxypropyltrimethoxysilane. After soaking, the powder is taken out and dried at 80-90°C to a moisture content of less than 1%. The powder is then crushed to a particle size of 80-120 meshes using a jet mill, and finally graded and screened using a vibrating screen to obtain a modified attapulgite powder having a particle size of more than 80 meshes for later use.

4. The production process of WPC molded floor according to claim 3, characterized in that: The primary modified attapulgite powder is subjected to secondary modification: the primary modified attapulgite powder is placed in a dopamine hydrochloride Tris-HCl buffer solution with a concentration of 2-4 wt%, stirred at room temperature for reaction for 12-15 hours, washed with deionized water multiple times to neutrality after the reaction, and then vacuum dried at 60-70° C. for 8-10 hours. The dried attapulgite powder is then subjected to plasma treatment, with a plasma treatment power of 80-100 W, a treatment time of 3-5 minutes, and neon as the treatment gas; The pH of the dopamine hydrochloride Tris-HCl buffer solution is 8.5-8.

8.

5. The production process of WPC molded floor according to claim 1, characterized in that: The blending and granulation steps are as follows: the mixing conditions of the high-speed mixer are 800-1000 r / min, the temperature is increased to 110-120° C., and the mixing is performed for 5-8 minutes; the mixing conditions of the low-speed mixer are 200-300 r / min, the temperature is reduced to 40-50° C., and the mixing is performed for 3-5 minutes; the temperature of the first zone of the twin-screw extruder is 160-170° C., the temperature of the second zone is 170-180° C., the temperature of the third zone is 180-190° C., the temperature of the fourth zone is 190-200° C., the temperature of the fifth zone is 200-210° C., the head temperature is 200-205° C., and the screw speed is 180-220 r / min.

6. The production process of WPC molded floor according to claim 1, characterized in that: In the extrusion molding step, the temperature of the feeding section of the single-screw extruder is 160-170°C, the temperature of the compression section is 170-180°C, the temperature of the metering section is 180-190°C, the temperature of the die head is 190-200°C, and the extrusion speed is 15-20m / min.

7. The production process of WPC molded floor according to claim 1, characterized in that: In the hot pressing shaping step, the hot pressing temperature is increased from room temperature to 150-158° C. at a heating rate of 5-8° C. / min, the pressure is 8-10 MPa, the holding time is 10-12 min, and after the holding time is completed, the temperature is lowered to room temperature at a cooling rate of 6-8° C. / min.

8. The production process of WPC molded floor according to claim 1, characterized in that: The surface treatment step is as follows: UV coating is applied by flow coating, the coating thickness is controlled at 0.08-0.12 mm, the UV paint used is polyurethane acrylate UV paint, the ultraviolet lamp power in the UV curing machine is 120-150 W, the curing temperature is 75-80° C., and the curing speed is 8-12 m / min; during embossing treatment, the embossing roller temperature is 120-130° C., the pressure is 3-5 MPa, and the embossing roller pattern depth is 0.1-0.3 mm.

9. The production process of WPC molded floor according to claim 1, characterized in that: In the cooling and cutting step, the air cooling speed is 8-12 m / s and the water cooling temperature is 15-20°C.

10. The production process of WPC molded floor according to claim 1, characterized in that: In the preforming step, the pre-pressing pressure is 3-5 MPa, the temperature is 130-136° C., and the pre-pressing time is 1-2 min; In the surface hardening treatment step, the hardening liquid containing nano-silica is composed of 5-5.8% nano-silica by mass, 2-2.5% silane coupling agent KH570, 0.7-0.8% dispersant sodium polyacrylate, and the balance deionized water, and the average particle size of the nano-silica is 20-30nm. The hardening liquid is prepared by stirring evenly, the immersion time is 15-20 minutes, and the hardening liquid temperature is 40-50°C.

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