A coated abrasive and substrate for processing formaldehyde-free boards, and a method for preparing the same.

Abstract

This invention discloses a coated abrasive and a substrate for processing formaldehyde-free boards, and their preparation method. The substrate preparation process is as follows: Substrate shaping: shaping temperature is 200~250℃, shaping tension is 650~750 N, and shaping time is 2~4 min; Substrate impregnation: impregnation material coating amount is 30~100 g / m 2 The viscosity of the impregnating material is 100~600 mPa·s, the drying temperature is 160~190℃, and the drying time is 2~4 min; the back coating of the substrate is 70~150 g / m². 2 The viscosity of the back scraping material is 3000~6000 mpa·s, the drying temperature of the back scraping material is 120~180℃, and the drying time is 2~4 min; the front side of the substrate is polished: the front side of the substrate is polished in four passes through a polishing machine equipped with 240 mesh, 320 mesh, 400 mesh and 400 mesh sanding belts.

Description

Technical Field

[0001] This invention belongs to the field of grinding, specifically relating to a coated abrasive and a substrate for processing formaldehyde-free boards, and a method for preparing the same. Background Technology

[0002] Formaldehyde-free engineered wood products: Engineered wood products made primarily from wood or non-wood plant fiber materials, processed into various material units, and produced with or without the application of formaldehyde-free adhesives and without the addition of other additives containing formaldehyde, and meeting the specified requirements, are called formaldehyde-free engineered wood products, or simply formaldehyde-free engineered wood products.

[0003] Coated abrasives: These are abrasives made by adhering abrasive to a flexible substrate with an adhesive, also known as flexible abrasives.

[0004] Substrate treatment: The substrate to be coated is treated to give it certain rigidity, strength, flatness, and good appearance.

[0005] Rubber compounds include substrate treatment rubber compounds and abrasive coating manufacturing rubber compounds. Substrate treatment rubber compounds include impregnation compounds and coating slurry compounds; abrasive coating manufacturing rubber compounds include base compounds, top-coating compounds, and coating compounds.

[0006] Formaldehyde, ranked second on my country's list of preferred controlled toxic chemicals, is receiving increasing attention. Formaldehyde-containing boards release formaldehyde and other harmful substances during processing and use, threatening human health. As awareness of the dangers of indoor formaldehyde deepens, countries worldwide are imposing increasingly stringent requirements on formaldehyde emissions from engineered wood products, leading to the widespread development and application of formaldehyde-free boards. However, currently, there are no specifically developed coating abrasives for formaldehyde-free boards and other wood-based materials. In the future, coating abrasives will develop towards specialization, high efficiency, environmental friendliness, and low cost.

[0007] Patent Title: A High-Strength Antistatic Coated Abrasive Fabric and Its Processing Technology; Patent Number: CN112677063A.

[0008] The aforementioned patent provides a processing technology for high-strength antistatic coated abrasive cloth, which adds an antistatic agent to the impregnating material, the front coating material, and the back scraping material to improve the antistatic performance of the cloth, but does not mention the composition of the antistatic agent.

[0009] Patent Title: An Antistatic Cloth-Based Coated Abrasive and its Manufacturing Method; Patent Number: CN112720283A.

[0010] The aforementioned patent provides an antistatic cloth-based coated abrasive, in which antistatic non-sand-coated adhesive and sand-coated adhesive are respectively applied to the non-sand-coated and sand-coated surfaces of the cloth base formed by impregnating the cloth with an antistatic impregnation adhesive, thereby forming a conductive path inside the cloth base and reducing the resistance value of the cloth base.

[0011] Patent Title: A special grinding tool for grinding medium and high density boards and its manufacturing method; Patent Number: CN103862396A.

[0012] The aforementioned patent discloses a special grinding tool for grinding medium and high density boards. In the coating process and its manufacturing, zirconium corundum abrasive is introduced to improve the wear resistance and impact resistance of medium and high density boards during rough grinding, prevent excessive abrasive shedding during grinding, and achieve higher grinding efficiency and lifespan than silicon carbide abrasive belts.

[0013] Patent Title: A High-Strength Antistatic Adhesive for Coating Abrasives; Patent Number: CN107236341A.

[0014] The aforementioned patent provides a high-bonding-strength antistatic adhesive for coated abrasives, which can effectively improve bonding strength and has good adhesion and antistatic properties.

[0015] Formaldehyde-free engineered wood products contain a large amount of formaldehyde-free adhesives. Currently, commonly used formaldehyde-free adhesives on the market are mainly polyurethane, ethyl acetate, and polyacrylate adhesives. Compared to formaldehyde-containing adhesives such as phenolic and urea-formaldehyde resins, formaldehyde-free adhesives have better toughness and lower hardness, making them more prone to adhering to and clogging the surface of the abrasive belt during grinding, causing belt failure and affecting its grinding life. Currently, the grinding of formaldehyde-free boards still uses traditional abrasive belts, which suffer from problems such as easy clogging of the belt surface, abrasive particles easily falling off in flakes, and high grinding heat that can burn the workpiece. Summary of the Invention

[0016] This invention provides a coated abrasive for processing formaldehyde-free boards, a substrate, and a method for preparing the same. Through special treatment of the substrate and optimized design of the base adhesive, top adhesive, and super coating formulations, a coated abrasive for processing formaldehyde-free boards is prepared to solve problems such as easy clogging of the abrasive belt surface, easy shedding of abrasive particles, and high grinding heat that can burn the workpiece in existing formaldehyde-free board processing processes.

[0017] The coated abrasive of the present invention is mainly used for thickness grinding and quantitative grinding of artificial boards, and particularly relates to thickness grinding and quantitative grinding of formaldehyde-free artificial boards or formaldehyde-free artificial board products.

[0018] The present invention discloses a method for preparing a coated abrasive for processing formaldehyde-free boards, comprising two steps: substrate treatment and manufacturing a large roll of coated abrasive.

[0019] The substrate treatment includes four processes: shaping, impregnation, back coating, and front sanding; the substrate is polyester fabric, pure cotton fabric, or polyester-cotton blend fabric; the substrate weight is 200~600 g / m². 2 The substrate width is 1350~1650mm;

[0020] The setting process involves a setting temperature of 200-250℃, a setting tension of 650-750 N, and a setting time of 2-4 minutes; the impregnation process involves an impregnation material coating amount of 30-100 g / m². 2 The viscosity of the impregnating material is 100~600 mPa·s, the drying temperature is 160~190 ℃, and the drying time is 2~4 min; in the back-side coating process, the coating amount is 70~150 g / m². 2 The viscosity of the back scraping material is 3000~6000 mpa·s, the drying temperature of the back scraping material is 120~180 ℃, and the drying time is 2~4 min; in the front grinding process, the front of the substrate is successively passed through a grinding machine equipped with 240 mesh, 320 mesh, 400 mesh and 400 mesh abrasive belts for four grinding passes, the grinding pressure is 180~220 N, the substrate running speed is 20~30 m / min, and the grinding roller rotation speed is 1000~1500 r / min.

[0021] The impregnating material, by weight percentage, consists of: water-soluble phenolic resin: 10-35%, polyvinyl acetate emulsion: 20-30%, polyvinyl alcohol aqueous solution (concentration 8-12wt%): 5-15%, styrene-butadiene latex: 5-15%, filler: 15-25%, penetrant: 0.5-1%, antistatic agent: 1-3%, thermally conductive material: 1-5%, defoamer: 0.5-1%, and dispersant: 1-2%.

[0022] The filler is wollastonite; the penetrant is fatty alcohol polyoxyethylene ether; the antistatic agent is one or a mixture of two of carbon black and graphite in any proportion; the thermally conductive material is one or a mixture of two or more of nano alumina, nano zinc oxide, nano silicon carbide, and fibrous carbon powder in any proportion; the defoamer is polyether-modified silicone oil; and the dispersant is a polyacrylate copolymer solution.

[0023] The impregnation material preparation process is as follows: water-soluble phenolic resin and polyvinyl acetate emulsion are added to the mixing pot and stirred evenly. Then, polyvinyl alcohol aqueous solution, styrene-butadiene latex, penetrant, antistatic agent, thermal conductive material, defoamer, and dispersant are added in sequence and stirred evenly. After stirring evenly, filler is added and stirring is continued for 10-50 minutes. Finally, water is added to adjust the impregnation material to the process viscosity value.

[0024] By weight percentage, the back coating material consists of: water-soluble phenolic resin: 20-35%, styrene-butadiene latex: 10-25%, filler: 30-50%, antistatic agent: 1-3%, thermally conductive material: 1-4.5%, defoamer: 0.5-1%, and dispersant: 1-2%.

[0025] The filler is a mixture of one or two of chalk and calcium carbonate in any proportion; the antistatic agent is a mixture of one or two of carbon black and graphite in any proportion; the thermally conductive material is a mixture of one or more of nano-alumina, nano-zinc oxide, nano-silicon carbide, and fibrous carbon powder in any proportion; the defoamer is polyether-modified silicone oil; the dispersant is a polyacrylate copolymer solution; the back scraping material preparation process is as follows: water-soluble phenolic resin and styrene-butadiene latex are added to a mixing pot and stirred evenly. Then, the antistatic agent, thermally conductive material, defoamer, and dispersant are added and stirred evenly. Finally, the filler is added and stirred for 10-50 minutes. Finally, a solvent (usually water) is added to adjust the viscosity of the back scraping material to the process value.

[0026] The substrate prepared by the above method.

[0027] The manufacturing process of the coated abrasive roll for formaldehyde-free board processing includes 11 steps: uncoiling the treated substrate, applying primer, sanding, primary drying, applying top coat, secondary drying, hot winding, curing, coating, tertiary drying, and rewinding.

[0028] The unwinding process of the treated substrate has an unwinding speed of 10~50 m / min and an unwinding tension of 500~800 N.

[0029] In the primer application process, the primer application amount is 30~400 g / m². 2 The viscosity of the base adhesive is 300~3000 mpa·s, and the coating temperature is 40±2℃;

[0030] In the sand-coating process, the abrasive is one or a mixture of two or more of silicon carbide, brown corundum, zirconium corundum, and ceramic corundum in any proportion, and the sand-coating density is 80~950 g / m³. 2 The abrasive particle size is 16~800 mesh;

[0031] The drying process is carried out at a temperature of 80-105°C for 30-90 minutes.

[0032] In the coating process, the coating amount is 30~400 g / m². 2 The viscosity of the adhesive is 300~3000 mpa·s, and the coating temperature is 40±2℃;

[0033] The secondary drying process involves a drying temperature of 70~115 ℃ and a drying time of 60~120 min.

[0034] The hot winding process is carried out at a temperature of 110~115℃.

[0035] The curing process is carried out at a curing temperature of 110~115 ℃ and a curing time of 2~6 h.

[0036] In the coating process, the amount of supercoating material is 200~700 g / m2, the viscosity of the supercoating material is 2000~6500 mpa·s, and the coating temperature is room temperature;

[0037] The three drying processes are performed at a temperature of 50-115 ℃ and a drying time of 60-120 min.

[0038] The winding process is carried out at room temperature.

[0039] By weight percentage, the primer composition is as follows: water-soluble phenolic resin: 30~40%, water-soluble polyurethane: 10~15%, filler: 35~55%, penetrant: 0.5~1%, reinforcing agent: 0.5~1.5%, antistatic agent: 1~3%, thermally conductive material: 1~4%, dispersant: 0.5~2%.

[0040] The filler is one or a mixture of two of chalk and wollastonite in any proportion; the penetrant is fatty alcohol polyoxyethylene ether; the reinforcing agent is aminopropyltetraethoxysilane; the antistatic agent is one or a mixture of two of carbon black and graphite in any proportion; the thermally conductive material is one or more of nano-alumina, nano-zinc oxide, nano-silicon carbide, and fibrous carbon powder; and the dispersant is a polyacrylate copolymer solution.

[0041] The preparation process of the primer is as follows: water-soluble phenolic resin and water-soluble polyurethane are added to a mixing pot and stirred evenly. Then, penetrant, reinforcing agent, antistatic agent, thermally conductive material, and dispersant are added in sequence and stirred evenly. After stirring evenly, filler is added and stirred for 10-50 minutes. Finally, solvent is added to adjust the viscosity of the primer to the process value. The solvent is water.

[0042] By weight percentage, the composition of the composite adhesive is as follows: water-soluble phenolic resin: 30~60%, filler: 30~60%, leveling agent: 0.5~1.5%, reinforcing agent: 0.5~1%, antistatic agent: 1~3%, thermally conductive material: 1~4%, pigment: 0.5~1%, dispersant: 0.5~2%.

[0043] The filler is one or a mixture of two or more of wollastonite, cryolite, potassium fluoroborate, and sodium fluoroborate in any proportion; the leveling agent is one or a mixture of two or more of polydimethylsiloxane, polymethylphenylsiloxane, and organic-modified polysiloxane in any proportion; the reinforcing agent is aminopropyltetraethoxysilane; the antistatic agent is one or a mixture of two of carbon black and graphite in any proportion; the thermally conductive material is one or more of nano-alumina, nano-zinc oxide, nano-silicon carbide, and fibrous carbon powder; the pigment is a water-soluble blue pigment or iron oxide red; and the dispersant is a polyacrylate copolymer solution.

[0044] The preparation process of the composite adhesive is as follows: water-soluble phenolic resin is added to a mixing pot and stirred evenly. Then, leveling agent, reinforcing agent, antistatic agent, thermally conductive material, and dispersant are added and stirred evenly. Filler is then added and stirred for 10-50 minutes. Finally, pigment is added and stirring continues for 10-50 minutes. After the above materials are stirred evenly, solvent is added to adjust the viscosity to the process value. The solvent is water.

[0045] The composition of the supercoating material by weight percentage is as follows: epoxy resin: 5~25%, curing agent: 5~25%, active filler: 40~80%, leveling agent: 0.5~1.5%, antistatic agent: 1~3%, pigment: 0.5~1.5%, film-forming agent: 0.5~2%, dispersant: 0.5~2%.

[0046] The curing agent is a mixture of one or more of diethylenetriamine, triethylenetetramine, and ethylenediamine in any proportion; the active filler is a mixture of one or more of cryolite, zinc stearate, calcium stearate, potassium fluoroborate, and sodium fluoroborate in any proportion; the leveling agent is a mixture of one or more of polydimethylsiloxane, polymethylphenylsiloxane, and organic-modified polysiloxane in any proportion; the antistatic agent is a mixture of one or more of carbon black and graphite in any proportion; the pigment is an oil-soluble blue pigment or iron oxide red; the film-forming agent and dispersant are both polyacrylate copolymer solutions; and the solvent is ethylene glycol ethyl ether.

[0047] The preparation process of the supercoating is as follows:

[0048] Preparation of Component A: Add epoxy resin, active filler, and appropriate amount of solvent to the mixing pot, stir evenly, then add leveling agent, antistatic agent, film-forming agent, dispersant, and pigment in sequence, and continue stirring for 10-50 minutes to obtain Component A;

[0049] Preparation of Component B: Add the curing agent and an appropriate amount of solvent to the mixing pot and stir for 3 minutes to obtain Component B;

[0050] Pour components A and B into the mixing pot and stir well. Then add solvent and adjust the viscosity of the coating material to the process value.

[0051] Preferably, the shaping process takes 2-3 minutes.

[0052] Preferably, in the impregnation process, the amount of impregnating material is 50~80 g / m². 2 The viscosity of the impregnating material is 100~400 mpa·s, the drying temperature of the impregnating material is 170~180 ℃, and the drying time is 2~3 min;

[0053] Preferably, in the back-side coating process, the coating amount is 90~130 g / m². 2 The viscosity of the back scraping material is 3000~4000 mPa·s.

[0054] The above preparation method yields a coated abrasive for processing formaldehyde-free boards.

[0055] Impregnating material: The adhesive system is composed of water-soluble phenolic resin, polyvinyl acetate emulsion, and polyvinyl alcohol. After curing, the phenolic resin forms a three-dimensional network structure. The long polymer chains of polyvinyl acetate and polyvinyl alcohol can form an interpenetrating network structure with the network structure of phenolic resin, improving the adhesion between the adhesive and the substrate and the strength of the adhesive film itself. After impregnation and drying, the substrate has good mechanical properties. Styrene-butadiene latex imparts a certain degree of toughness and impact resistance to the substrate. The Si-O bonds in the wollastonite filler form a "bridge" structure between the polymer chains, further improving the adhesive strength and also improving the wear resistance and strength of the substrate. Penetrant. It can improve the permeability of the impregnating material, making it easier for the impregnating material to penetrate into the fabric gaps and improve the filling capacity of the impregnating material; the antistatic agent imparts a certain conductivity to the substrate, which can transfer the charge generated during grinding and reduce the electrostatic adsorption of grinding debris; the thermally conductive material can transfer the grinding heat through the substrate to the outside of the abrasive cloth; the defoamer can eliminate or slow down the bubbles caused by foaming aids such as emulsions; the dispersant can make the filler, antistatic agent, and thermally conductive material evenly dispersed inside the substrate, forming a continuous conductive and thermally conductive channel, improving the antistatic and thermal conductivity of the substrate. In addition, the improved dispersibility of the filler can also improve the mechanical properties of the substrate.

[0056] Backing material: Water-soluble phenolic resin constitutes the adhesive system, resulting in a highly rigid and heat-resistant film after curing. Styrene-butadiene latex imparts a certain degree of toughness and impact resistance to the back of the substrate. Fillers provide the back of the substrate with a certain degree of abrasion resistance and rigidity, while also improving the bonding strength of the backing material. Antistatic agents impart a certain degree of conductivity to the back of the substrate, transferring the charge generated during grinding and reducing the electrostatic adsorption of grinding debris. Thermally conductive materials transfer grinding heat through the substrate to the outside of the abrasive cloth. Defoamers eliminate or slow down the formation of bubbles caused by foaming agents such as emulsions. Dispersants ensure that fillers, antistatic agents, and thermally conductive materials are evenly dispersed in the adhesive layer on the back of the substrate, forming continuous conductive and thermally conductive channels, improving the antistatic and thermal conductivity of the adhesive layer on the back of the substrate. In addition, improved filler dispersibility also enhances the mechanical properties of the adhesive layer on the back of the substrate.

[0057] Base Adhesive: The adhesive system consists of water-soluble phenolic resin and water-soluble polyurethane. Polyurethane improves the flexibility and bonding strength of the base adhesive. Fillers impart abrasion resistance and mechanical properties to the adhesive while also improving its bonding strength. Penetrants enhance the permeability of the base adhesive, allowing some of it to penetrate the substrate and form "keys" that physically bond with it, significantly increasing the substrate's hold on the base adhesive. Reinforcing agents improve the adhesive's bonding strength to the abrasive. Antistatic agents impart conductivity to the base adhesive layer, transferring charges generated during grinding and reducing electrostatic adsorption of grinding debris. Thermally conductive materials transfer grinding heat to the outside of the abrasive cloth. Dispersants ensure that fillers, antistatic agents, and thermally conductive materials are evenly dispersed within the adhesive layer, forming continuous conductive and thermally conductive channels, improving the antistatic and thermal conductivity of the adhesive layer. Furthermore, improved filler dispersibility also enhances the mechanical properties of the adhesive layer.

[0058] The composite material consists of water-soluble phenolic resin, which, after curing, produces a film with high stiffness, good impact resistance, and good heat resistance. Fillers include inert and active fillers. Inert fillers impart wear resistance and mechanical properties to the composite material while improving its adhesive strength. Active fillers undergo a phase change during grinding, absorbing heat and reducing heat generation during abrasive grinding, while also aiding in grinding. Leveling agents allow the composite material to flow better on the abrasive surface. Reinforcing agents improve the adhesive strength of the composite material to the abrasive. Antistatic agents impart conductivity to the composite layer, transferring charges generated during grinding and reducing electrostatic adsorption of grinding debris. Thermally conductive materials transfer grinding heat to the outside of the abrasive cloth. Pigments contribute to the appearance of the abrasive surface. Dispersants ensure uniform dispersion of fillers, antistatic agents, thermally conductive materials, and pigments within the composite layer, forming continuous conductive and thermally conductive channels, improving the antistatic and thermal conductivity of the composite layer. Furthermore, improved filler dispersibility also enhances the mechanical properties of the composite layer.

[0059] Supercoating: The epoxy resin and curing agent form the adhesive system, giving the adhesive layer certain adhesion and film-forming properties; the active filler absorbs heat and undergoes a phase change during grinding, which can reduce the heat during sanding and also has certain grinding aid and lubrication effects, improving grinding performance and reducing sanding surface clogging; the leveling agent can make the supercoating material flow better on the sanding surface; the antistatic agent gives the supercoating material certain conductivity, which can transfer the charge generated during grinding and reduce the electrostatic adsorption of grinding debris; the pigment can give the sanding surface a certain appearance; the film-forming agent imparts or improves the film-forming properties of the supercoating material; the dispersant can make the active filler, antistatic agent, and pigment uniformly dispersed in the adhesive layer, forming continuous conductive and thermally conductive channels, improving the antistatic and thermal conductivity of the adhesive layer. In addition, the improved dispersibility of the filler can also improve the mechanical properties of the adhesive layer.

[0060] The substrate treatment and adhesive formulation of coated abrasives used in formaldehyde-free board processing significantly impact product performance. Conventional substrate treatment for coated abrasives in board processing typically includes four steps: shaping, impregnation, back coating, and front coating, to ensure high surface smoothness and excellent mechanical properties. The substrate treatment of the coated abrasives for formaldehyde-free board processing involved in this invention includes only four steps: shaping, impregnation, back coating, and front sanding. This reduces the front coating step, allowing a small amount of primer to penetrate the substrate, forming a "key" that physically bonds with the substrate. This significantly improves the substrate's hold on the primer and prevents the abrasive from peeling off in large sheets due to the primer layer. Furthermore, to ensure the substrate surface smoothness meets requirements, a front sanding step is added to eliminate deep pits on the substrate surface, ensuring the smoothness of the coated abrasive surface.

[0061] Antistatic agents are added to the impregnation slurry and back scraping slurry during substrate treatment, and to the base rubber, re-rubber, and coating materials during abrasive manufacturing. This antistatic treatment creates a current path from the front to the back of the abrasive, improving its antistatic performance and preventing electrostatic adsorption of abrasive debris on the abrasive belt surface, thus improving the belt's anti-clogging performance. A certain amount of thermally conductive material is added to the impregnation slurry, back scraping slurry, base rubber, re-rubber, and coating materials, forming a continuous thermally conductive network from the back to the front of the abrasive cloth. This improves the abrasive cloth's heat conduction capacity and facilitates heat dissipation. The base rubber formulation undergoes toughening and bonding enhancement treatments to improve the impact resistance and adhesion strength of the base rubber layer, reducing abrasive chip detachment caused by workpiece impact and extending the abrasive cloth's service life. The coating material formulation is improved by optimizing the types and increasing the content of active fillers in the coating material to reduce grinding heat during belt grinding and prevent workpiece burns.

[0062] The invention provides a method for preparing a coated abrasive for processing formaldehyde-free boards, and the performance of the invented product is improved by 30% compared with conventional products on the market. Attached Figure Description

[0063] Figure 1 This is a physical image of a formaldehyde-free engineered wood panel after being ground using the belt abrasive according to Embodiment 1 of the present invention. Detailed Implementation

[0064] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. In the following embodiments, the polyacrylate copolymer solution has a solid content of 38-42 wt%, a viscosity of 25-60 mPa·s, and a pH of 3.3-3.8.

[0065] Example 1:

[0066] The adhesive formulation described in this embodiment is as follows:

[0067] The impregnating material is composed of the following by weight percentage: water-soluble phenolic resin: 20%, polyvinyl acetate emulsion: 30%, polyvinyl alcohol (CAS No.: 9002-89-5): 10%, styrene-butadiene latex: 10%, wollastonite: 20%, fatty alcohol polyoxyethylene ether (CAS No.: 111-09-3): 1%, antistatic agent: 3%, nano zinc oxide: 3%, polyether modified silicone oil: 1%, and polyacrylate copolymer solution: 2%.

[0068] The water-soluble phenolic resin is a type A water-soluble phenolic resin with a viscosity of 1800-2500 mPa·s, a solid content of 75-79 wt%, a gel time of 13-16 min at 120℃, and a water dilution ratio of ≥1:2.5 at 30℃; the polyvinyl acetate emulsion has a solid content of 18-30% and a viscosity of 8000 mPa·s (25℃); the polyvinyl alcohol is a 10 wt% polyvinyl alcohol 1799 solution, prepared as follows: add 10 parts of polyvinyl alcohol 1799 granules to 90 parts of water, turn on the stirrer, and then start heating. The heating curve is from room temperature to 95℃, and the heating time is 30 min. When the temperature reaches 95℃, continue stirring until all the polyvinyl alcohol 1799 granules are dissolved, then stop stirring to prepare a 10% polyvinyl alcohol 1799 solution; the styrene-butadiene latex has a pH between 6 and 7 and an effective ingredient content of 40±2 wt%; the wollastonite has a density of 2.8. g / cm 3 The pH of the fatty alcohol polyoxyethylene ether is between 6 and 7; the antistatic agent is carbon black and graphite in a mass ratio of 1:1; and the nano zinc oxide has a particle size between 1 and 100 nm.

[0069] The impregnation material preparation process is as follows: Water-soluble phenolic resin and polyvinyl acetate emulsion are added to a mixing pot. The stirrer is turned on and the speed is set to 600 r / min for 3 minutes. Then, polyvinyl alcohol, styrene-butadiene latex, fatty alcohol polyoxyethylene ether, antistatic agent, nano zinc oxide, polyether-modified silicone oil, and polyacrylate copolymer solution are added sequentially. The stirrer speed is adjusted to 800 r / min, and the stirring time is 15 minutes. After thorough mixing, wollastonite is added, and stirring continues for 30 minutes. Finally, water is added to adjust the viscosity of the impregnation material to 200 mPa·s.

[0070] By weight percentage, the back coating material consists of: water-soluble phenolic resin: 32%, styrene-butadiene latex: 20%, filler: 40%, antistatic agent: 2%, nano zinc oxide: 3%, polyether modified silicone oil: 1%, and polyacrylate copolymer solution: 2%.

[0071] The water-soluble phenolic resin is a first-order water-soluble phenolic resin with a viscosity of 1800-2500 mPa·s, a solid content of 75-79 wt%, a gel time of 13-16 min at 120℃, and a water dilution ratio of ≥1:2.5 at 30℃; the styrene-butadiene latex has a pH between 6 and 7 and an effective ingredient content of 40±2 wt%; the filler is calcium carbonate, wherein CaCO3 ≥90%, moisture <1%, and particle size is: ≤1% on a 120-mesh sieve and ≤5% on a 230-mesh sieve; the antistatic agent is carbon black and graphite in a mass ratio of 1:1; the nano zinc oxide has a particle size between 1-100 nm.

[0072] The preparation process of the back-coating material is as follows: Water-soluble phenolic resin and styrene-butadiene latex are added to the mixing pot. The stirrer is turned on and the speed is set to 600 r / min for 3 minutes. Then, antistatic agent, nano-zinc oxide, polyether-modified silicone oil, and polyacrylate copolymer solution are added all at once, and stirring continues for 15 minutes. After thorough mixing, calcium carbonate is added, and stirring continues for 30 minutes. Finally, solvent water is added to adjust the viscosity of the back-coating material to 4000 mPa·s.

[0073] By weight percentage, the base compound consists of: water-soluble phenolic resin: 35%, water-soluble polyurethane: 15%, wollastonite: 40%, fatty alcohol polyoxyethylene ether (CAS No.: 111-09-3): 1%, aminopropyltetraethoxysilane: 1%, antistatic agent: 3%, nano zinc oxide: 3%, and polyacrylate copolymer solution: 2%.

[0074] The water-soluble phenolic resin is a stage A water-soluble phenolic resin with a viscosity of 600-1200 mPa·s, a solid content of 69-75 wt%, a gel time of 7-10 min at 120℃, and a water dilution ratio of ≥1:0.7 at 20℃; the water-based polyurethane has a viscosity of 800-1400 mPa·s, a solid content of 63-68 wt%, and a curing time of 11-15 min / 60℃; the fatty alcohol polyoxyethylene ether has a pH between 6 and 7; and the wollastonite has a density of 2.8 g / cm³. 3 The antistatic agent is carbon black and graphite in a mass ratio of 1:1.

[0075] The preparation process for the primer is as follows: Water-soluble phenolic resin and water-soluble polyurethane are added to a mixing pot. The stirrer is turned on and set to 600 rpm for 3 minutes. Then, fatty alcohol polyoxyethylene ether, aminopropyltetraethoxysilane, antistatic agent, nano zinc oxide, and polyacrylate copolymer solution are added sequentially, and stirring continues for 15 minutes. After thorough mixing, wollastonite is added, and stirring is continued for 30 minutes. Finally, solvent water is added to adjust the primer viscosity to 1500 mPa·s.

[0076] By weight percentage, the composite composition is as follows: water-soluble phenolic resin: 40%, filler: 50%, polydimethylsiloxane: 1%, aminopropyltetraethoxysilane: 1%, antistatic agent: 3%, nano zinc oxide: 2.5%, iron oxide red: 1%, polyacrylate copolymer solution: 1.5%.

[0077] The water-soluble phenolic resin is a first-order water-soluble phenolic resin with a viscosity of 600-1200 mPa·s, a solid content of 69-75 wt%, a gel time of 7-10 min at 120℃, and a water dilution ratio of ≥1:0.7 at 20℃; the filler is wollastonite, cryolite, and potassium fluoroborate in a mass ratio of 1:3:3; the antistatic agent is carbon black and graphite in a mass ratio of 1:1.

[0078] The preparation process of the composite adhesive is as follows: Water-soluble phenolic resin is added to a mixing pot. The stirrer is turned on and the speed is 600 r / min. Then, polydimethylsiloxane, aminopropyltetraethoxysilane, antistatic agent, nano-zinc oxide, and polyacrylate copolymer solution are added one at a time, and stirred for 15 min. After uniform mixing, filler is added, and stirring is continued for 30 min. Finally, iron oxide red is added, and stirring continues for 30 min. After the above materials are uniformly mixed, solvent water is added to adjust the viscosity to 1000 mPa·s.

[0079] The super coating composition by weight percentage is: epoxy resin: 10%, curing agent: 12%, active filler: 70%, polydimethylsiloxane: 1.5%, antistatic agent: 2.5%, iron oxide red: 1%, film-forming agent: 1.5%, dispersant: 1.5%.

[0080] The epoxy value of the epoxy resin is 0.48~0.54; the curing agent is triethylenetetramine; the active filler is composed of cryolite, zinc stearate, and potassium fluoroborate in a mass ratio of 1:2:2; the antistatic agent is carbon black and graphite in a mass ratio of 1:1; the film-forming agent and dispersant are both polyacrylate copolymer solutions.

[0081] Preparation of Component A: Add epoxy resin, active filler, and an appropriate amount of solvent (ethylene glycol ethyl ether, added to facilitate stirring) to a mixing pot. Turn on the stirrer and set the stirrer speed to 600 r / min for 15 min. Then add the leveling agent, antistatic agent, film-forming agent, dispersant, and pigment in sequence, and continue stirring for 30 min to obtain Component A.

[0082] To prepare component B: Add the curing agent and an appropriate amount of solvent (ethylene glycol ethyl ether) to the mixing pot and stir for 3 minutes to prepare component B.

[0083] The preparation process of the supercoating is as follows: Component A and Component B are poured into a mixing pot, the stirrer is turned on, the stirrer speed is 600 r / min, and the stirring time is 1 min. Then, the solvent ethylene glycol ethyl ether is added to adjust the viscosity to 4500 mPa·s;

[0084] This embodiment includes two steps: substrate treatment and manufacturing of coated abrasive rolls.

[0085] The substrate treatment includes four processes: shaping, impregnation, back coating, and front polishing.

[0086] The substrate is polyester fabric; the weight of the substrate is 360 g / m². 2 The substrate has a width of 1400 mm.

[0087] The shaping process has a shaping temperature of 220 ℃, a shaping tension of 700 N, and a shaping time of 3 min;

[0088] The impregnation process involves an impregnation material coating amount of 70 g / m. 2 The drying temperature of the impregnating material is 160~190 ℃, and the drying time is 3 min.

[0089] In the back-side coating process, the coating amount is 130 g / m². 2 The drying temperature of the back scraping material is 120~180 ℃, and the drying time is 3 min;

[0090] In the aforementioned front-side polishing process, the front side of the substrate is sequentially polished four times by a polishing machine equipped with 240-grit, 320-grit, 400-grit, and 400-grit abrasive belts. The polishing pressure is 200 N, the substrate running speed is 25 m / min, and the polishing roller rotation speed is 1200 r / min.

[0091] The manufacturing process of the coated abrasive roll includes 11 steps: unwinding the treated substrate, applying primer, sanding, primary drying, applying top coat, secondary drying, hot winding, curing, coating, tertiary drying, and rewinding.

[0092] The unwinding process of the treated substrate has an unwinding speed of 35 m / min and an unwinding tension of 650 N.

[0093] In the primer application process, the primer application amount is 280 g / m². 2 The adhesive application temperature is 40±2℃;

[0094] In the sand-coating process, the abrasive types are silicon carbide and zirconium corundum, with a mass ratio of 6:1 and a sand-coating density of 750 g / m³. 2 The abrasive particle size is 36 mesh;

[0095] The drying temperature curve for the first drying process is: 85℃-20min, 95℃-20min, 100℃-20min;

[0096] In the adhesive coating process, the adhesive coating amount is 300 g / m². 2 The adhesive application temperature is 40±2℃;

[0097] The secondary drying process has the following drying temperature curves: 65℃-25min, 80℃-25min, 92℃-25min, 102℃-25min, 110℃-25min.

[0098] The hot winding process is carried out at a temperature of 113 ℃.

[0099] The curing process is carried out at a curing temperature of 115°C for 3.5 hours.

[0100] In the coating process, the amount of super coating material applied is 450 g / m². 2 The adhesive application temperature is room temperature;

[0101] The drying temperature curves for the three drying processes are: 65℃-25min, 80℃-25min, 92℃-25min, 102℃-25min, and 110℃-25min.

[0102] The winding process is carried out at room temperature.

[0103] The coated abrasive roll prepared in the examples was kneaded and left to stand before being made into an abrasive belt with a width * circumference of 1400 * 4000 mm. This belt was then mounted on a board grinding machine for grinding experiments. The grinding object was a formaldehyde-free engineered wood panel with a width * length of 1000 * 2500 mm. The grinding method was constant thickness grinding, and the abrasive belt speed was 15 m / s. The number of boards ground and the surface condition of the boards after grinding were recorded. In Example 1, a total of 2618 formaldehyde-free engineered wood panels were ground. No burns were observed on the surface of the boards after grinding. Details of the ground boards can be found in [link to example]. Figure 1 .

[0104] Comparative Example 1:

[0105] Comparative Example 1 uses the RC851 abrasive belt for grinding plates, which is commonly produced and sold by Baige Company. The grinding parameters and grinding objects are the same as in Example 1. The number of plates ground and the surface condition of the plates after grinding are recorded.

[0106] Comparative Example 1: A total of 1,960 formaldehyde-free engineered wood panels were ground, and no burns were found on the surface of the panels.

[0107] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the specific implementation of the present invention and not to limit it. Those skilled in the art should understand that any equivalent substitutions or obvious modifications made to the implementation of the present invention without changing its performance or use, without departing from the spirit of the present invention, should be covered within the scope of protection claimed by the present invention.

Claims

1. A method for preparing a coated abrasive substrate for processing formaldehyde-free boards, characterized in that, The process is as follows: (1) Substrate setting: The setting temperature is 200~250℃, the setting tension is 650~750 N, and the setting time is 2~4 min; (2) Substrate impregnation: The amount of impregnating material is 30~100 g / m 2 The impregnating material has a viscosity of 100~600 mPa·s, a drying temperature of 160~190 ℃, and a drying time of 2~4 min. By mass percentage, the impregnating material comprises: water-soluble phenolic resin: 10~35%, polyvinyl acetate emulsion: 20~30%, polyvinyl alcohol aqueous solution: 5~15%, styrene-butadiene latex: 5~15%, filler: 15~25%, penetrant: 0.5~1%, antistatic agent: 1~3%, thermally conductive material: 1~5%, defoamer: 0.5~1%, and dispersant: 1~2%. The filler is wollastonite; the penetrant is fatty alcohol polyoxyethylene ether; and the antistatic agent is one or a mixture of two of carbon black and graphite in any proportion. The impregnating material is a mixture of one or more of nano-alumina, nano-zinc oxide, nano-silicon carbide, and fibrous carbon powder in any proportion; the defoamer is polyether-modified silicone oil; the dispersant is a polyacrylate copolymer solution; the above impregnating material is obtained through the following process: water-soluble phenolic resin and polyvinyl acetate emulsion are added to a mixing pot and stirred evenly, followed by the sequential addition of polyvinyl alcohol aqueous solution, styrene-butadiene latex, penetrant, antistatic agent, thermally conductive material, defoamer, and dispersant, and stirred evenly. After stirring evenly, filler is added, and stirring is continued for 10-50 minutes. Water is added to adjust the impregnating material to the process viscosity value. (3) Backside coating of substrate: The amount of coating material applied to the backside is 70~150 g / m 2 The viscosity of the back-scraping material is 3000~6000 mPa·s, the drying temperature is 120~180 ℃, and the drying time is 2~4 hours. The back scraping material, by mass percentage, comprises: water-soluble phenolic resin: 20-35%, styrene-butadiene latex: 10-25%, filler: 30-50%, antistatic agent: 1-3%, thermally conductive material: 1-4.5%, defoamer: 0.5-1%, and dispersant: 1-2%. The filler is one or a mixture of two of chalk and calcium carbonate in any proportion; the antistatic agent is one or a mixture of two of carbon black and graphite in any proportion; the thermally conductive material is one or a mixture of more than two of nano-alumina, nano-zinc oxide, nano-silicon carbide, and fibrous carbon powder in any proportion; the defoamer is polyether-modified silicone oil; and the dispersant is a polyacrylate copolymer solution. The back scraping material is obtained through the following process: water-soluble phenolic resin and styrene-butadiene latex are added to a mixing pot and stirred evenly. Then, the antistatic agent, thermally conductive material, defoamer, and dispersant are added and stirred evenly. The filler is then added and stirred for 10-50 minutes. Water is added to adjust the viscosity of the back scraping material to the process value. (4) Grinding of the front side of the substrate: The front side of the substrate is successively ground by a grinding machine equipped with 240-grit, 320-grit, 400-grit and 400-grit sanding belts. The grinding pressure is 180~220 N, the substrate running speed is 20~30 m / min, and the grinding roller speed of the grinding machine is 1000~1500 r / min.

2. The method for preparing the coated abrasive substrate for formaldehyde-free board processing according to claim 1, characterized in that, The substrate is polyester fabric, pure cotton fabric, or polyester-cotton blended fabric; the weight of the substrate is 200~600 g / m². 2 The substrate width is 1350~1650mm.

3. A coating abrasive substrate for processing formaldehyde-free boards prepared by the preparation method described in claim 1 or 2.

4. A method for preparing a coated abrasive for processing formaldehyde-free boards using the substrate described in claim 3, characterized in that, The process is as follows: (1) Unwind the substrate at a speed of 10~50 m / min and a tension of 500~800 N; (2) Apply primer, with a coverage of 30~400 g / m². 2 The primer viscosity is 300~3000 mPa·s, and the application temperature is 40±2℃. By mass percentage, the primer composition is: water-soluble phenolic resin: 30~40%, water-soluble polyurethane: 10~15%, filler: 35~55%, penetrant: 0.5~1%, reinforcing agent: 0.5~1.5%, antistatic agent: 1~3%, thermally conductive material: 1~4%, dispersant: 0.5~2%. The filler is one or a mixture of two of chalk and wollastonite in any proportion. The penetrant is fatty alcohol polyoxyethylene ether. The reinforcing agent is aminopropyltetraethoxysilane. The antistatic agent... The base adhesive is a mixture of one or two of carbon black and graphite in any proportion; the thermally conductive material is a mixture of one or more of nano-alumina, nano-zinc oxide, nano-silicon carbide, and fibrous carbon powder in any proportion; the dispersant is a polyacrylate copolymer solution. The base adhesive is obtained through the following process: water-soluble phenolic resin and water-soluble polyurethane are added to a mixing pot and stirred evenly. Then, a penetrant, reinforcing agent, antistatic agent, thermally conductive material, and dispersant are added in sequence and stirred evenly. Then, filler is added and stirred for 10-50 minutes. Water is added to adjust the viscosity of the base adhesive to the process value. (3) Abrasive coating: The abrasive type is one or more of silicon carbide, brown corundum, zirconium corundum, and ceramic corundum in any proportion, and the abrasive coating density is 80~950 g / m³. 2 The abrasive particle size is 16~800 mesh; (4) Drying once, the drying temperature is 80~105 ℃, and the drying time is 30~90 min; (5) Apply a top coat of adhesive, with a coating amount of 30~400 g / m. 2 The viscosity of the adhesive is 300~3000 mPa·s, and the coating temperature is 40±2℃. By mass percentage, the adhesive composition is: water-soluble phenolic resin: 30~60%, filler: 30~60%, leveling agent: 0.5~1.5%, reinforcing agent: 0.5~1%, antistatic agent: 1~3%, thermally conductive material: 1~4%, pigment: 0.5~1%, dispersant: 0.5~2%. The filler is one or a mixture of two or more of wollastonite, cryolite, potassium fluoroborate, and sodium fluoroborate in any proportion. The leveling agent is one or more of polydimethylsiloxane, polymethylphenylsiloxane, and organic-modified polysiloxane. The above-mentioned composite material is obtained through the following process: water-soluble phenolic resin is added to a mixing pot, stirring is started, leveling agent, reinforcing agent, antistatic agent, thermal conductive material and dispersant are added, and after stirring evenly, filler is added, and stirring is carried out for 10-50 min. Finally, pigment is added, and stirring is continued for 10-50 min. After the above materials are stirred evenly, water is added to adjust the viscosity to the process value. (6) Secondary drying, with a drying temperature of 70~115 ℃ and a drying time of 60~120 min; (7) Hot winding, the hot winding temperature is 110~115 ℃; (8) Curing, the curing temperature is 110~115 ℃, and the curing time is 2~6 h; (9) Apply an overcoat layer, with an overcoat material application rate of 200~700 g / m. 2 The viscosity of the overcoating material is 2000~6500. The coating temperature is room temperature (MPa·s). The supercoating layer, by mass percentage, comprises: epoxy resin: 5-25%, curing agent: 5-25%, active filler: 40-80%, leveling agent: 0.5-1.5%, antistatic agent: 1-3%, pigment: 0.5-1.5%, film-forming agent: 0.5-2%, and dispersant: 0.5-2%. The curing agent is a mixture of one or more of diethylenetriamine, triethylenetetramine, and ethylenediamine in any proportion. The active filler is a mixture of one or more of cryolite, zinc stearate, calcium stearate, potassium fluoroborate, and sodium fluoroborate in any proportion. The leveling agent is a mixture of one or more of polydimethylsiloxane, polymethylphenylsiloxane, and organic-modified polysiloxane in any proportion. The antistatic agent is a mixture of one or more of carbon black and graphite in any proportion. The film-forming agent and dispersant are polyacrylate copolymer solutions. The above supercoating material is obtained through the following process: Preparation of Component A: Add epoxy resin, active filler, and appropriate amount of solvent to the mixing pot, stir evenly, then add leveling agent, antistatic agent, film-forming agent, dispersant, and pigment in sequence, and continue stirring for 10-50 minutes to obtain Component A; Preparation of Component B: Add the curing agent and an appropriate amount of solvent to the mixing pot and stir for 3 minutes to obtain Component B; Pour components A and B into the mixing pot, stir well, then add solvent to adjust the viscosity of the coating material to the process value; (10) Drying is carried out three times, with a drying temperature of 50~115 ℃ and a drying time of 60~120 min; (11) Rewinding, the rewinding temperature is room temperature.

5. The coated abrasive for processing formaldehyde-free boards prepared by the method of claim 4.

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