Low-density high-filled spc flooring and method for manufacturing the same

Abstract

This invention discloses a method for preparing low-density, high-filler SPC flooring. The method is characterized by a raw material formulation comprising the following components in the indicated weight proportions: 100 parts graft-modified PVC resin, 300-350 parts filler, 9-12 parts heat stabilizer, 3-5 parts melt processing modifier, 3-5 parts reinforcing and toughening modifier, 1-2 parts external lubricant, 1-2 parts internal lubricant, 2-5 parts chemical foaming agent, and 2-5 parts foaming aid. The graft-modified PVC resin is prepared by replacing the chlorine atoms in PVC with p-aminothiophenol, followed by an amidation reaction between a diacid or polyacid and an amino group. Its advantages are: 1) It improves the melt strength and expandability of the PVC resin, ensuring foaming performance under high filler content. Compared with ordinary SPC flooring, the flooring product has lower density and lighter weight, higher hardness, and lower overall formulation cost compared to ordinary low-density SPC flooring. 2) The process is simple, and the product has high controllability.

Description

Technical Field

[0001] This invention relates to SPC flooring production technology, and in particular to a method for preparing low-density, high-filling SPC flooring by micro-foaming extrusion. Background Technology

[0002] PVC flooring is a very popular new type of floor decoration material on the market. Since its introduction to China in the 1980s, it has gained widespread acceptance in the domestic market and is widely used in schools, offices, hospitals, shopping malls, homes, and many other places. PVC flooring is made from polyvinyl chloride as the base material, with the addition of fillers, plasticizers, stabilizers, and other additives. It is produced by combining wear-resistant layers and paint layers through processes such as extrusion, calendering, and hot pressing. Currently, the most widely used PVC flooring products on the market are LVT flooring, WPC flooring, and SPC flooring.

[0003] The structural composition of SPC flooring, from bottom to top, consists of: a sound-absorbing layer, a substrate layer, a color film layer, a wear-resistant layer, and a UV coating layer. The substrate layer determines the overall basic performance of the flooring. Currently, SPC flooring products generally have a high density, resulting in expensive transportation costs. Lowering the density of SPC flooring helps save material usage, reduce flooring density, decrease transportation costs, and facilitates installation. Polymer foaming technology involves multiple material performance parameters, including melt strength, melt index, and melt crystallization cooling. PVC resin has poor melt properties; during foaming, due to its low melt strength, it is prone to cell collapse and rupture, resulting in poor expandability. Furthermore, it requires the addition of large amounts of additives and fillers to assist processing, making the production of SPC foamed flooring very difficult. Adding processing aids such as ACR can improve the expandability of PVC to some extent, but with large amounts of fillers and high filler ratios, foaming remains very difficult.

[0004] Chinese invention patent CN110626027A discloses a method for preparing co-extruded SPC foam flooring. This method employs a multi-layer co-extrusion process, dividing the flooring into three layers: a first stabilizing layer, a foaming layer, and a second stabilizing layer, from top to bottom. This method significantly reduces the overall density of the flooring by placing a foaming layer between the two stabilizing layers. However, the manufacturing process is relatively complex, has poor controllability, and results in a thicker flooring, making construction inconvenient.

[0005] Invention patent CN112895642A discloses a plasticizer-free micro-foamed PVC flooring and its preparation method. The flooring structure, from bottom to top, consists of a rigid transparent PVC sheet, a rigid micro-foamed SPC substrate, a PVC printed layer, and a rigid transparent PVC sheet surface layer. The flooring as a whole is plasticizer-free, and the substrate layer also exhibits micro-foaming characteristics. However, considering the SPC foamed substrate layer, this invention has a high proportion of PVC matrix resin, resulting in higher manufacturing costs. Summary of the Invention

[0006] To reduce the weight and formulation cost of conventional SPC flooring products while maintaining high hardness, this invention provides a method for preparing low-density, high-filling SPC flooring.

[0007] The technical solution adopted in this invention is: a method for preparing low-density, high-filling SPC flooring, characterized in that the raw material formula includes the following components in the following weight proportions: 100 parts of graft-modified PVC resin, 300-350 parts of filler, 9-12 parts of heat stabilizer, 3-5 parts of melt processing modifier, 3-5 parts of reinforcing and toughening modifier, 1-2 parts of external lubricant, 1-2 parts of internal lubricant, 2-5 parts of chemical foaming agent, and 2-5 parts of foaming aid; the graft-modified PVC resin is prepared by replacing the chlorine atom of PVC with p-aminothiophenol, followed by an amidation reaction between a dibasic acid or a polybasic acid and an amino group.

[0008] As a further improvement of the present invention, the grafted modified PVC resin is prepared according to the following steps:

[0009] A. Place PVC resin powder in a mixed solution of N,N-dimethylformamide and deionized water under a nitrogen atmosphere, and add p-aminothiophenol. React at 50-70°C for 16-24 hours. After the reaction is completed, take out the reaction product, wash the product and place it in an N,N-dimethylformamide solution containing anhydrous sodium sulfate to remove water, and obtain dehydrated powder.

[0010] B. The dehydrated powder is placed in N,N-dimethylformamide solvent, and a diacid or polyacid is added. An amidation reaction is carried out at 80-90°C under a nitrogen atmosphere. During the reaction, water is continuously removed. The reaction product is washed and dried to obtain the grafted modified PVC resin.

[0011] As a further improvement of the present invention, the filler is heavy calcium carbonate and / or light calcium carbonate with a particle size of 100-500 mesh.

[0012] As a further improvement of the present invention, the heat stabilizer is selected from one or any combination of calcium-zinc stabilizers, organotin stabilizers, and rare earth stabilizers.

[0013] As a further improvement of the present invention, the melt processing modifier is selected from one or any combination of acrylic copolymers, styrene-acrylonitrile copolymers, and modified PVC resins.

[0014] As a further improvement of the present invention, the reinforcing and toughening modifier is chlorinated polyethylene or methyl methacrylate-butadiene-styrene terpolymer.

[0015] As a further improvement of the present invention, the external lubricant is selected from one or more of polyethylene wax, oxidized polyethylene wax, and natural paraffin wax; the internal lubricant is selected from one or more of calcium stearate, fatty acid ester, and fatty alcohol.

[0016] As a further improvement of the present invention, the chemical foaming agent is an AC foaming agent and / or a DC foaming agent; the foaming aid is selected from one or any combination of zinc oxide, stearate, and phosphate.

[0017] The present invention can be prepared according to the following steps: each raw material measured according to the production raw material formula is added to a high-speed mixer for premixing to obtain a premix; the premix is ​​then added to a twin-screw extruder through a feeding system, and after full melt blending, it is extruded through a die, cooled, and cut into sheets to obtain a low-density, high-filling SPC flooring product.

[0018] The high-speed mixer is set to operate at a temperature of 35–45°C, a rotation speed of 600–800 r / min, and a premixing time of 6–10 min. The twin-screw extruder has the following extrusion temperatures: conveying section gradually increases from 170°C to 180°C; compression section gradually increases from 180°C to 185°C; metering section gradually decreases from 185°C to 175°C; and the die head temperature is set to 170–175°C. The screw rotation speed is set to 90–120 r / min.

[0019] The present invention also discloses a low-density, high-filling SPC flooring, which is prepared by the method of the present invention.

[0020] The beneficial effects of this invention are: 1) By grafting and modifying PVC resin, this invention improves the melt strength and expandability of PVC resin, ensuring foaming performance under high filler content. Compared with ordinary SPC flooring, the flooring product has lower density and lighter weight, higher hardness and lower overall formula cost compared with ordinary SPC low-density flooring. 2) The process of this invention is simple and the product has high controllability. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the PVC resin grafting modification of the present invention. Detailed Implementation

[0022] The present invention will be further described below with reference to embodiments.

[0023] Preparation of graft-modified resin:

[0024] The grafted modified resin was prepared according to the following method:

[0025] (1) PVC resin powder was placed in a mixed solution of N,N-dimethylformamide and deionized water under a nitrogen atmosphere, and p-aminothiophenol was added. The reaction was carried out at 65°C for 20 hours. After the reaction was completed, the reaction product was taken out. The reaction product was washed and placed in an N,N-dimethylformamide solution containing anhydrous sodium sulfate to remove water, and dehydrated powder was obtained.

[0026] (2) The dehydrated powder is placed in N,N-dimethylformamide solvent, adipic acid is added, and amidation reaction is carried out at 92°C under nitrogen atmosphere. During the reaction, water is continuously removed. The reaction product is washed and dried to obtain the grafted modified PVC resin.

[0027] Example 1:

[0028] SPC flooring products are prepared according to the following method:

[0029] S1. The raw materials are measured according to the following weight ratio: 100 parts of grafted modified PVC resin, 330 parts of filler, 10 parts of heat stabilizer, 3 parts of melt processing modifier, 4 parts of reinforcing and toughening modifier, 1.3 parts of external lubricant, 1.2 parts of internal lubricant, 2.5 parts of chemical foaming agent, and 2.5 parts of foaming aid.

[0030] The filler is heavy calcium carbonate with a particle size of 300 mesh, the heat stabilizer is calcium-zinc stabilizer, the melt processing modifier is an acrylic copolymer, the reinforcing and toughening modifier is chlorinated polyethylene, the external lubricant is polyethylene wax, the internal lubricant is calcium stearate, the chemical foaming agent is AC foaming agent, and the foaming aid is zinc oxide.

[0031] S2. Add the raw materials measured according to the production raw material formula to a high-speed mixer for premixing. The working temperature of the high-speed mixer is set to 40℃, the speed is set to 800 r / min, and the premixing time is 6 min to obtain a premixed material. Then, add the premixed material to a twin-screw extruder through a feeding system. The extrusion molding temperature of the twin-screw extruder is set as follows: conveying section 170℃, 175℃, 180℃; compression section 180℃, 180℃, 185℃, 185℃, 185℃, 185℃; metering section 185℃, 185℃, 180℃, 175℃; die head temperature is set to 170℃. The screw speed is set to 100 r / min. After thorough melt blending, the material is extruded through a die, cooled, and cut into sheets to obtain a low-density, high-filling SPC flooring product.

[0032] The performance of the obtained SPC flooring was tested, and the results are shown in Table 1.

[0033] Example 2:

[0034] SPC flooring products are prepared according to the following method:

[0035] S1. The raw materials are measured according to the following weight ratio of the production raw material formula: 100 parts of grafted modified PVC resin, 330 parts of filler, 10 parts of heat stabilizer, 3 parts of melt processing modifier, 4 parts of reinforcing and toughening modifier, 1.3 parts of external lubricant, 1.2 parts of internal lubricant, 4 parts of chemical foaming agent, and 4 parts of foaming aid.

[0036] The filler is heavy calcium carbonate with a particle size of 300 mesh, the heat stabilizer is calcium-zinc stabilizer, the melt processing modifier is an acrylic copolymer, the reinforcing and toughening modifier is chlorinated polyethylene, the external lubricant is polyethylene wax, the internal lubricant is calcium stearate, the chemical foaming agent is AC foaming agent, and the foaming aid is zinc oxide.

[0037] S2. Add the raw materials measured according to the production raw material formula to a high-speed mixer for premixing. The working temperature of the high-speed mixer is set to 40℃, the speed is set to 800 r / min, and the premixing time is 6 min to obtain a premixed material. Then, add the premixed material to a twin-screw extruder through a feeding system. The extrusion molding temperature of the twin-screw extruder is set as follows: conveying section 170℃, 175℃, 180℃; compression section 180℃, 180℃, 185℃, 185℃, 185℃, 185℃; metering section 185℃, 185℃, 180℃, 175℃; die head temperature is set to 170℃. The screw speed is set to 100 r / min. After thorough melt blending, the material is extruded through a die, cooled, and cut into sheets to obtain a low-density, high-filling SPC flooring product.

[0038] The performance of the obtained SPC flooring was tested, and the results are shown in Table 1.

[0039] Example 3:

[0040] SPC flooring products are prepared according to the following method:

[0041] S1. The raw materials are measured according to the following weight ratio: 100 parts of grafted modified PVC resin, 330 parts of filler, 10 parts of heat stabilizer, 3 parts of melt processing modifier, 4 parts of reinforcing and toughening modifier, 1.3 parts of external lubricant, 1.2 parts of internal lubricant, 4 parts of chemical foaming agent, and 2 parts of foaming aid.

[0042] The filler is heavy calcium carbonate with a particle size of 300 mesh, the heat stabilizer is calcium-zinc stabilizer, the melt processing modifier is an acrylic copolymer, the reinforcing and toughening modifier is chlorinated polyethylene, the external lubricant is polyethylene wax, the internal lubricant is calcium stearate, the chemical foaming agent is a mixture of AC foaming agent and DC foaming agent in a 1:1 ratio, and the foaming aid is zinc oxide.

[0043] S2. Add the raw materials measured according to the production raw material formula to a high-speed mixer for premixing. The working temperature of the high-speed mixer is set to 40℃, the speed is set to 800r / min, and the premixing time is 8min to obtain a premixed material. Then, add the premixed material to a twin-screw extruder through a feeding system. The extrusion molding temperature of the twin-screw extruder is set as follows: conveying section 170℃, 175℃, 180℃; compression section 180℃, 180℃, 185℃, 185℃, 185℃; metering section 185℃, 185℃, 180℃, 175℃; die head temperature is set to 170℃. The screw speed is set to 90r / min. After thorough melt blending, the material is extruded through a die, cooled, and cut into sheets to obtain a low-density, high-filling SPC flooring product.

[0044] The performance of the obtained SPC flooring was tested, and the results are shown in Table 1.

[0045] Comparative Example 1:

[0046] This comparative example is the same as Example 1, implemented according to the same steps and conditions, and all raw materials are from the same batch as in Example 1. The only difference is that the resin used is unmodified PVC resin. The specific steps are as follows:

[0047] S1. Measure the raw materials according to the following weight ratio: 100 parts PVC resin, 330 parts filler, 10 parts heat stabilizer, 3 parts melt processing modifier, 4 parts reinforcing and toughening modifier, 1.3 parts external lubricant, 1.2 parts internal lubricant, 2.5 parts chemical foaming agent, and 2.5 parts foaming aid.

[0048] The filler is heavy calcium carbonate with a particle size of 300 mesh, the heat stabilizer is calcium-zinc stabilizer, the melt processing modifier is an acrylic copolymer, the reinforcing and toughening modifier is chlorinated polyethylene, the external lubricant is polyethylene wax, the internal lubricant is calcium stearate, the chemical foaming agent is AC foaming agent, and the foaming aid is zinc oxide.

[0049] S2. Add the raw materials measured according to the production raw material formula to a high-speed mixer for premixing. The working temperature of the high-speed mixer is set to 40℃, the speed is set to 800 r / min, and the premixing time is 6 min to obtain a premixed material. Then, add the premixed material to a twin-screw extruder through a feeding system. The extrusion molding temperature of the twin-screw extruder is set as follows: conveying section 170℃, 175℃, 180℃; compression section 180℃, 180℃, 185℃, 185℃, 185℃, 185℃; metering section 185℃, 185℃, 180℃, 175℃; die head temperature is set to 170℃. The screw speed is set to 100 r / min. After thorough melt blending, the material is extruded through a die, cooled, and cut into sheets to obtain a low-density, high-filling SPC flooring product.

[0050] The performance of the obtained SPC flooring was tested, and the results are shown in Table 1.

[0051] Table 1. SPC Flooring Performance Test Results

[0052]

[0053] As can be seen from Table 1, compared with ordinary SPC flooring, the low-density, high-filling SPC flooring produced by the method of the present invention has a lower density and lighter weight; compared with ordinary low-density SPC flooring, it has higher hardness and lower cost.

[0054] Meanwhile, a comparison between Example 1 and Comparative Example 1 shows that the present invention significantly improves the cell uniformity and molding effect of low-density, high-filling SPC flooring by modifying the resin, and significantly reduces the weight of the flooring while keeping the hardness basically unchanged, achieving remarkable progress.

Claims

1. A method for preparing low-density, high-filling SPC flooring, characterized in that, The raw material formula includes the following components in the indicated weight proportions: 100 parts grafted modified PVC resin, 300-350 parts filler, 9-12 parts heat stabilizer, 3-5 parts melt processing modifier, 3-5 parts reinforcing and toughening modifier, 1-2 parts external lubricant, 1-2 parts internal lubricant, 2-5 parts chemical foaming agent, and 2-5 parts foaming aid. The grafted modified PVC resin is prepared by replacing the chlorine atoms in PVC with p-aminothiophenol, followed by an amidation reaction between a dibasic acid or a polybasic acid and an amino group.

2. The method for preparing low-density, high-filling SPC flooring according to claim 1, characterized in that, The grafted modified PVC resin is prepared according to the following steps: A. Place PVC resin powder in a mixed solution of N,N-dimethylformamide and deionized water under a nitrogen atmosphere, and add p-aminothiophenol. React at 50-70°C for 16-24 hours. After the reaction is completed, take out the reaction product, wash the product and place it in an N,N-dimethylformamide solution containing anhydrous sodium sulfate to remove water, and obtain dehydrated powder. B. The dehydrated powder is placed in N,N-dimethylformamide solvent, and a diacid or polyacid is added. An amidation reaction is carried out at 80-90°C under a nitrogen atmosphere. During the reaction, water is continuously removed. The reaction product is washed and dried to obtain the grafted modified PVC resin.

3. The method for preparing low-density, high-filling SPC flooring according to claim 2, characterized in that: The filler is heavy calcium carbonate and / or light calcium carbonate with a particle size of 100-500 mesh.

4. The method for preparing low-density, high-filling SPC flooring according to claim 2, characterized in that: The heat stabilizer is selected from one or more of calcium-zinc stabilizers, organotin stabilizers, and rare earth stabilizers.

5. The method for preparing low-density, high-filling SPC flooring according to claim 2, characterized in that: The melt processing modifier is selected from one or more of acrylic copolymers, styrene-acrylonitrile copolymers, and modified PVC resins.

6. The method for preparing low-density, high-filling SPC flooring according to claim 2, characterized in that: The reinforcing and toughening modifier is chlorinated polyethylene or methyl methacrylate-butadiene-styrene terpolymer.

7. The method for preparing low-density, high-filling SPC flooring according to claim 2, characterized in that: The external lubricant is selected from one or more of polyethylene wax, oxidized polyethylene wax, and natural paraffin wax; the internal lubricant is selected from one or more of calcium stearate, fatty acid ester, and fatty alcohol.

8. The method for preparing low-density, high-filling SPC flooring according to claim 2, characterized in that: The chemical foaming agent is AC foaming agent and / or DC foaming agent; the foaming aid is selected from one or any combination of zinc oxide, stearate, and phosphate.

9. The method for preparing low-density, high-filling SPC flooring according to any one of claims 1 to 8, characterized in that: The process also includes adding the raw materials measured according to the production raw material formula to a high-speed mixer for premixing to obtain a premix; then adding the premix to a twin-screw extruder through a feeding system, and after full melting and blending, extruding through a die, cooling, and cutting the board, obtaining a low-density, high-filling SPC flooring product.

10. The method for preparing low-density, high-filling SPC flooring according to claim 9, characterized in that: The high-speed mixer is set to operate at a temperature of 35–45°C, a speed of 600–800 r / min, and a premixing time of 6–10 min. The extrusion molding temperature of the twin-screw extruder is set as follows: the conveying section gradually increases from 170°C to 180°C; the compression section gradually increases from 180°C to 185°C; the metering section gradually decreases from 185°C to 175°C; the die head temperature is set to 170–175°C; and the screw speed is set to 90–120 r / min.

11. A low-density, high-filling SPC floor prepared by the method of any one of claims 1 to 10.

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