Special anti-blocking sandpaper for paint polishing and preparation method thereof

Abstract

The present application relates to the technical field of sandpaper, especially to the field of IPC B24D11, further to a special anti-blocking sandpaper for paint polishing and a preparation method thereof.From bottom to top, the sandpaper comprises a substrate, a first adhesive layer, an abrasive layer, a second adhesive layer and an anti-blocking coating layer.The modified abrasive obtained by electrostatic sanding process can be adsorbed on the substrate to achieve a coverage of 30% to 50%, and uneven distribution phenomenon does not occur, and the surface resistance of the sandpaper can be 10 6 Ω, and has good water resistance and excellent anti-blocking property.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of sandpaper, in particular to the field of IPC B24D11, and further relates to a special anti-blocking sandpaper for paint polishing and a preparation method thereof. BACKGROUND

[0002] At present, sandpaper, as a kind of grinding tool made by adhering abrasive materials to soft paper base with adhesive, has been widely used to polish the surface of paint products such as metal and wood due to its convenience and low price. In the prior art, sandpaper is mainly composed of sandpaper base, adhesive and abrasive, but it is prone to static electricity, and when used for polishing paint, especially high-viscosity paint or paint with poor dryness, it is prone to blockage, which reduces the service life. Some sandpaper cannot be used when it is wet or damp

[0003] Chinese patent CN202211715037 discloses an anti-blocking ceramic sandpaper and a preparation method thereof, which comprises, from bottom to top, latex paper, primer, abrasive, compound adhesive and anti-blocking coating. The anti-blocking coating is prepared from the following components by weight fraction: water-based emulsion 30-50 parts, graded filler 10-15 parts, dispersing agent 3-5 parts, water-soluble curing agent 2-3 parts and water 60-70 parts. The graded filler is ceramic corundum particles with the following grading: particle size R<250nm, 1-3%; 250≤R<350nm, 65-75%; 350nm≤R<450nm, 15-19%; 450≤R<550nm, 3-5%. The anti-blocking effect of the anti-blocking coating is greatly improved, and the sharpness and self-sharpening of the surface layer of the sandpaper are effectively improved. However, the technical solution requires high-temperature calcination of the filler, which is complex, and the technical solution only relates to the anti-blocking property, and does not relate to the water resistance and anti-static property of the sandpaper. SUMMARY

[0004] The present application provides a special anti-blocking sandpaper for paint polishing, which comprises, from bottom to top, a substrate, a first adhesive layer, an abrasive layer, a second adhesive layer and an anti-blocking coating.

[0005] Preferably, the substrate is latex paper.

[0006] Preferably, the first adhesive layer comprises, by mass fraction, modified resin 80-120 parts, ammonium chloride 1-2 parts, coupling agent 0.05-1 parts and leveling agent 0.05-1 parts.

[0007] Preferably, the modified resin is at least one selected from polyvinyl acetate emulsion modified urea-formaldehyde resin, melamine modified urea-formaldehyde resin and silicone modified urea-formaldehyde resin.

[0008] Preferably, the modified resin is melamine modified urea-formaldehyde resin.

[0009] Preferably, the melamine modified urea-formaldehyde resin has a solid content of 60-85wt% and a viscosity of 800-1200cps (30℃).

[0010] Preferably, the coupling agent is at least one selected from silane coupling agent, titanate coupling agent, aluminate coupling agent, metal complex coupling agent, phosphate coupling agent, borate coupling agent.

[0011] Preferably, the coupling agent is silane coupling agent.

[0012] Preferably, the silane coupling agent is at least one selected from KH 550, KH 560, KH 570, KH 792.

[0013] Preferably, the leveling agent is at least one selected from silicone type leveling agent, acrylate type leveling agent, fluorocarbon compound.

[0014] Preferably, the leveling agent is silicone type leveling agent.

[0015] Preferably, the silicone type leveling agent is at least one selected from polydimethylsiloxane, polyether modified organosiloxane.

[0016] Preferably, the preparation method of the first adhesive layer is as follows: mixing the modified resin, ammonium chloride, coupling agent and leveling agent uniformly according to mass fraction, and then obtaining the first adhesive layer.

[0017] Preferably, the abrasive layer is modified abrasive, and the raw materials of the modified abrasive include, by mass fraction, abrasive 90-110 parts, titanate coupling agent 1-2 parts, polyvinylpyrrolidone 2-3 parts, sodium dodecyl benzene sulfonate 1-2 parts, and water 100-150 parts.

[0018] Preferably, the abrasive is one or a combination of more than one selected from silicon carbide, brown corundum and white corundum.

[0019] Preferably, the abrasive is brown corundum.

[0020] Preferably, the brown corundum is calcined brown corundum.

[0021] Preferably, the polyvinylpyrrolidone has an average molecular weight of 30000-70000.

[0022] Preferably, the polyvinylpyrrolidone has an average molecular weight of 30000-40000.

[0023] Preferably, the preparation method of the modified abrasive is as follows: mixing the abrasive and water uniformly, then adding titanium ester coupling agent, polyvinylpyrrolidone and sodium dodecyl benzene sulfonate after heating to 55-65℃, stirring for 1-3h, centrifugal filtration and drying.

[0024] The applicant found in the experiment that the modified abrasive obtained by the application can achieve a coverage rate of 30%-50% when adsorbed on the substrate by the electrostatic sanding process, and does not have the phenomenon of uneven distribution. The lower the coverage rate, the larger the pore, the larger the space for accommodating chips, and the less likely to be blocked. Compared with the conventional abrasive which achieves a coverage rate of 70%, it has substantial progress.

[0025] The second adhesive layer comprises, by mass fraction, melamine modified urea-formaldehyde resin 80-120 parts, ammonium chloride 1-2 parts, functional additives 10-20 parts, silane coupling agent 0.05-0.15 parts, and acrylate type leveling agent 0.05-0.15 parts.

[0026] Preferably, the solid content of the melamine modified urea-formaldehyde resin is 60-85wt%, and the viscosity is 800-1200cps(30℃).

[0027] Preferably, the functional additives are selected from at least one of anti-adhesive A, water repellent, and antistatic agent.

[0028] Preferably, the functional additives include anti-adhesive A, water repellent, and antistatic agent.

[0029] Preferably, the mass ratio of the anti-adhesive A, water repellent, and antistatic agent is (4-7):(4-7):(4-7).

[0030] Preferably, the anti-adhesive A is selected from at least one of polydimethylsiloxane(PDMS), polyvinyl alcohol(PVA), hydrochloric acid polyvinylamide(HPAM), and polyhydroxyethyl methacrylate(HEMA).

[0031] Preferably, the anti-adhesive A is PDMS.

[0032] Preferably, the PDMS is polyepoxy modified polydimethylsiloxane.

[0033] Preferably, the viscosity of the polyepoxy modified polydimethylsiloxane is 800-2000cst.

[0034] Preferably, the water repellent is selected from at least one of silicone, polyurethane, acrylic acid, and fluorocarbon.

[0035] Preferably, the water repellent is a combination of acrylic acid and fluorocarbon.

[0036] Preferably, the mass ratio of the acrylic acid and the fluorocarbon is 1 : (2-5).

[0037] Preferably, the antistatic agent is selected from at least one of a cationic antistatic agent, an anionic antistatic agent, and a nonionic antistatic agent.

[0038] Preferably, the antistatic agent is a combination of an anionic antistatic agent and a nonionic antistatic agent.

[0039] Preferably, the mass ratio of the anionic antistatic agent and the nonionic antistatic agent is (5-8) : (1-3).

[0040] Preferably, the anionic antistatic agent is selected from at least one of an alkali metal salt of an alkyl sulfonic acid, an alkali metal salt of an alkyl sulfuric acid, an alkali metal salt of an alkyl benzene sulfonic acid, an alkali metal salt of an alkyl phosphoric acid, an alkali metal salt of a fatty alcohol ether phosphoric acid ester, and an alkali metal salt of a dithio carbamic acid.

[0041] Preferably, the anionic antistatic agent is a combination of an alkali metal salt of an alkyl sulfonic acid and an alkali metal salt of a fatty alcohol ether phosphoric acid ester.

[0042] Preferably, the mass ratio of the alkali metal salt of the alkyl sulfonic acid and the alkali metal salt of the fatty alcohol ether phosphoric acid ester is (5-8) : (1-3).

[0043] Preferably, the nonionic antistatic agent is selected from at least one of a fatty acid polyol ester antistatic agent, an alkanolamine antistatic agent, an alkanolamide antistatic agent, a polyoxyethylene antistatic agent, and an oxirane amine adduct antistatic agent.

[0044] Preferably, the nonionic antistatic agent is an oxirane amine adduct antistatic agent.

[0045] The applicant found in the experiment that when the second adhesive layer is selected to be the same as the first adhesive layer, the melamine modified urea-formaldehyde resin with solid content of 60-85wt% and viscosity of 800-1200cps (30°C), the obtained sandpaper has certain water resistance, but is prone to adhesion phenomenon, and is prone to static electricity. When the anti-adhesive A, the water-proof agent, and the anti-static agent are added in a mass ratio of (4-7):(4-7):(4-7), the anti-adhesion, the anti-static property, and the water resistance of the sandpaper are improved, and the anti-clogging performance of the sandpaper is also significantly improved, thereby prolonging the service life of the sandpaper. Especially when the anti-adhesive A is the polyepoxy modified polydimethylsiloxane with viscosity of 800-2000cst, the water-proof agent is the combination of acrylic acid and fluorocarbon in a mass ratio of 1:(2-5), and the anti-static agent is the combination of anionic anti-static agent and non-ionic anti-static agent in a mass ratio of (5-8):(1-3), the anti-adhesive, the water-proof agent, and the anti-static agent in the second adhesive layer system are maximized, and the melamine modified urea-formaldehyde resin is combined to avoid the adhesion of the sandpaper, the whitening of the adhesive layer of the sandpaper, and the clogging of the sandpaper when polishing paint, thereby avoiding the problem of rapid decrease of the service life. The applicant speculates that the second adhesive layer system formed by the anti-adhesive A, the water-proof agent, and the anti-static agent in a mass ratio of (4-7):(4-7):(4-7) has low surface tension, good fluidity, and enables the anti-adhesive A and the anti-static agent to form a regular adsorption layer on the surface of the sandpaper. At the same time, especially when the polyepoxy modified polydimethylsiloxane, the acrylic acid, the fluorocarbon, the anionic anti-static agent, and the non-ionic anti-static agent are combined, the interaction force between the paint chips and the adhesion between the paint chips in the sandpaper during use are reduced, thereby effectively improving the anti-clogging performance of the sandpaper. In addition, the water resistance of the adhesive film formed by the melamine modified urea-formaldehyde resin is further improved, and the sandpaper has good water resistance at 25°C and 100°C.

[0046] The applicant further found in the experiment that when the anionic anti-static agent is the combination of alkyl sulfonic acid alkali metal salt and fatty alcohol ether phosphate alkali metal salt in a mass ratio of (5-8):(1-3), the non-ionic anti-static agent is the ethylene oxide amine additive anti-static agent, and the mass ratio of the anionic anti-static agent and the non-ionic anti-static agent is controlled to be (5-8):(1-3), the surface resistance of the sandpaper can be 10 6 Ω, compared with the sandpaper with surface resistance of 10 12 Ω. The anti-static performance of the sandpaper obtained by the technical scheme has outstanding progress.

[0047] The applicant further found in the experiment that only when the coverage of the modified abrasive is less than 50% and the surface resistance of the sandpaper is less than 108 When the sandpaper prepared has good anti-sticking performance, it has good anti-clogging performance when polishing paint, and when one of the conditions is not met, the sandpaper is prone to clogging, causing the service life to drop sharply.

[0048] Preferably, the preparation method of the second adhesive layer is as follows: uniformly mix melamine modified urea-formaldehyde resin, ammonium chloride, functional additives, silane coupling agent and acrylate leveling agent by mass fraction to obtain the second adhesive layer.

[0049] Preferably, the preparation method of the anti-clogging coating layer is as follows:

[0050] (1) each raw material is weighed by mass fraction;

[0051] (2) uniformly stir 1-3 parts of polysiloxane-polyether copolymer, 3-5 parts of dispersant, 0.5-2 parts of fatty alcohol polyoxyethylene ether and 50-70 parts of water, then add 20-30 parts of stearate, 1-3 parts of anti-sticking agent B and continue to stir uniformly;

[0052] (3) add 10-15 parts of silicone-acrylate resin emulsion to step (2) and continue to stir uniformly;

[0053] (4) add 0.5-2 parts of dicumyl peroxide and 0.5-2 parts of N-acetylphenylhydrazine to step (3) and stir uniformly, then grind to obtain the anti-clogging coating layer.

[0054] Preferably, the dispersant is a combination of polysiloxane copolymer dispersant and lignin sulfonate dispersant.

[0055] Preferably, the mass ratio of the polysiloxane copolymer dispersant and the lignin sulfonate is (1-3):1.

[0056] Preferably, the stearate is a combination of calcium stearate and zinc stearate.

[0057] Preferably, the mass ratio of the calcium stearate and the zinc stearate is (0.5-2):(2-3).

[0058] Preferably, the anti-sticking agent B is a combination of polytetrafluoroethylene wax and PDMS.

[0059] Preferably, the mass ratio of the polytetrafluoroethylene wax and the PDMS is (0.2-0.8):1.

[0060] Preferably, the solid content of the silicone-acrylate resin emulsion is 40-55wt%.

[0061] The second aspect of the present application provides a preparation method of anti-clogging sandpaper special for paint polishing, comprising the following steps:

[0062] (1) coating the first adhesive layer on the substrate;

[0063] (2) adsorbing the modified abrasive on the substrate coated with the first adhesive layer by electrostatic sanding process;

[0064] (3) coating the second adhesive layer after drying of step (2);

[0065] (4) coating the anti-blocking coating layer after drying and curing of step (3) to obtain.

[0066] Preferably, the coating amount of the first adhesive layer is 10-40 g / m 2 .

[0067] Preferably, the coating amount of the second adhesive layer is 30-120 g / m 2 .

[0068] Preferably, the coating amount of the anti-blocking coating layer is 20-120 g / m 2 .

[0069] Preferably, the drying temperature in steps (2) and (3) is 50-90℃, and the drying time is 30-60 min.

[0070] Preferably, the curing time in step (3) is 80-100℃, and the curing time is 4-8 h.

[0071] The applicant found in the experiment that when the anti-blocking coating layer is coated after drying and curing of step (3), the adhesion of large adhesive paint debris to the surface of the sandpaper can be further prevented, thereby prolonging the service life of the sandpaper.

[0072] Beneficial effects:

[0073] 1. In the present application, the abrasive and water are mixed uniformly, and then the titanate coupling agent, polyvinylpyrrolidone and sodium dodecyl benzene sulfonate are added after being heated to 55-65℃, and stirred for 1-3 h. The modified abrasive obtained by centrifugal filtration and drying is adsorbed on the substrate by electrostatic sanding process, which can achieve a coverage rate of 30%-50% without uneven distribution, which is a substantial progress compared with the conventional abrasive which can only achieve a coverage rate of 70%.

[0074] 2. The anti-adhesion agent A, the water-proof agent and the anti-static agent are added in a mass ratio of (4-7):(4-7):(4-7), which can improve the anti-adhesion, anti-static and water-proof properties of the sandpaper, and significantly improve the anti-blocking performance and service life of the sandpaper.

[0075] 3、when the anti-adhesive agent A is a polyepoxy-modified polydimethylsiloxane with a viscosity of 800-2000cst, the waterproof agent is acrylic acid and fluorocarbon with a mass ratio of 1:(2-5), and the antistatic agent is a combination of anionic antistatic agent and non-ionic antistatic agent with a mass ratio of (5-8):(1-3), the anti-adhesive agent, the waterproof agent and the antistatic agent in the second adhesive layer system are maximized, and the combination of melamine-modified urea-formaldehyde resin avoids the problems of paper adhesion, white spots on the adhesive layer of the sandpaper and blockage of the sandpaper during sanding of the paint, thereby greatly reducing the service life of the sandpaper.

[0076] 4、when the anionic antistatic agent is a combination of alkali metal salt of alkyl sulfonic acid and alkali metal salt of fatty alcohol ether phosphate with a mass ratio of (5-8):(1-3), and the non-ionic antistatic agent is an ethylene oxide amine additive antistatic agent, and the mass ratio of the anionic antistatic agent and the non-ionic antistatic agent is controlled to be (5-8):(1-3), the surface resistance of the sandpaper can be 10 6 Ω when the polyepoxy-modified polydimethylsiloxane acrylic acid and fluorocarbon are combined. 12 Ω, the antistatic performance of the sandpaper obtained by the technical scheme of the present application has outstanding progress compared with the sandpaper with a surface resistance of 10

[0077] 5、the technical scheme of the present application can simultaneously achieve a modified abrasive with a coverage of less than 50%, a sandpaper with a surface resistance of less than 10 8 Ω and good anti-adhesion performance, and the sandpaper prepared has good anti-blocking performance during sanding of the paint. BRIEF DESCRIPTION OF DRAWINGS

[0078] Figure 1 The anti-blocking sandpaper prepared in Examples 1-2 and Comparative Examples 1-4 is shown in the following photographs.

[0079] In the figure: 1-Example 1; 2-Example 2; 3-Comparative Example 1; 4-Comparative Example 2; 5-Comparative Example 3; 6-Comparative Example 4. DETAILED DESCRIPTION

[0080] Example 1

[0081] Example 1 provides a special anti-blocking sandpaper for sanding of paint, which comprises, from bottom to top, a substrate, a first adhesive layer, an abrasive layer, a second adhesive layer and an anti-blocking coating layer.

[0082] The substrate is latex paper.

[0083] The first adhesive layer comprises, by mass fraction, 100 parts of modified resin, 1.5 parts of ammonium chloride, 0.08 parts of coupling agent and 0.08 parts of leveling agent.

[0084] The modified resin is melamine modified urea-formaldehyde resin.

[0085] The solid content of the melamine modified urea-formaldehyde resin is 80±2wt%, and the viscosity is 1000±100cps (30℃), which is purchased from Funneng Resin Co., Ltd. in Lin'an, Hangzhou.

[0086] The coupling agent is a silane coupling agent.

[0087] The silane coupling agent is KH 560.

[0088] The leveling agent is a silicone type leveling agent.

[0089] The silicone type leveling agent is polyether modified organosiloxane, model: BYK 349.

[0090] The preparation method of the first adhesive layer is as follows: mixing the modified resin, ammonium chloride, coupling agent and leveling agent uniformly according to mass fraction, and then obtaining the first adhesive layer.

[0091] The abrasive layer is modified abrasive. The raw materials of the modified abrasive include, by mass fraction, abrasive 100 parts, titanate coupling agent 1.5 parts, polyvinylpyrrolidone 2 parts, sodium dodecyl benzene sulfonate 1.5 parts, and water 100 parts.

[0092] The abrasive is brown corundum.

[0093] The brown corundum is calcined brown corundum, which is purchased from Henan Yedax New Material Technology Co., Ltd.

[0094] The average molecular weight of the polyvinylpyrrolidone is 40000, which is purchased from Yixing Biological Technology (Shanghai) Co., Ltd.

[0095] The preparation method of the modified abrasive is as follows: mixing the abrasive and water uniformly, then adding the titanate coupling agent, polyvinylpyrrolidone and sodium dodecyl benzene sulfonate after heating to 60℃, stirring and reacting for 2h, centrifugal filtration and drying, and then obtaining the modified abrasive.

[0096] The second adhesive layer includes, by mass fraction, melamine modified urea-formaldehyde resin 100 parts, ammonium chloride 1.5 parts, functional additives 15 parts, silane coupling agent 0.1 part, and acrylate type leveling agent 0.1 part.

[0097] The solid content of the melamine modified urea-formaldehyde resin is 80±2wt%, and the viscosity is 1000±100cps (30℃), which is purchased from Funneng Resin Co., Ltd. in Lin'an, Hangzhou.

[0098] The functional additives include anti-adhesive A, waterproof agent and antistatic agent.

[0099] The mass ratio of the anti-adhesive A, the water-proof agent, the anti-static agent is 5:5:7.

[0100] The anti-adhesive A is PDMS.

[0101] The PDMS is polyepoxy modified polydimethylsiloxane.

[0102] The viscosity of the polyepoxy modified polydimethylsiloxane is 1200 cst, and the model is Dow Corning XIAMETER TM OFX-5330.

[0103] The water-proof agent is a combination of acrylic acid and fluorocarbon, and the fluorocarbon is purchased from Nanjing Quanxi Chemical Co., Ltd.

[0104] The mass ratio of the acrylic acid and the fluorocarbon is 1:3.

[0105] The anti-static agent is a combination of anionic anti-static agent and non-ionic anti-static agent.

[0106] The mass ratio of the anionic anti-static agent and the non-ionic anti-static agent is 6:3.

[0107] The anionic anti-static agent is a combination of alkali metal salt of alkyl sulfonic acid and alkali metal salt of fatty alcohol ether phosphate.

[0108] The mass ratio of the alkali metal salt of alkyl sulfonic acid and the alkali metal salt of fatty alcohol ether phosphate is 5:3, the alkali metal salt of alkyl sulfonic acid is sodium alkyl sulfonate, the model is Germany Lanxess H95, and the alkali metal salt of fatty alcohol ether phosphate is potassium fatty alcohol ether phosphate, which is purchased from Haian Petroleum Chemical Factory in Jiangsu Province, and the model is MOA-3PK-70.

[0109] The non-ionic anti-static agent is an ethylene oxide amine addition anti-static agent, and the model is Germany Clariant SAS93.

[0110] The preparation method of the second adhesive layer is as follows: uniformly mixing melamine modified urea-formaldehyde resin, ammonium chloride, functional additives, silane coupling agent, and acrylate type leveling agent according to mass fraction, and then obtaining the second adhesive layer.

[0111] The preparation method of the anti-blocking coating layer is as follows:

[0112] (1) weighing each raw material according to mass fraction;

[0113] (2) uniformly stirring 2 parts of polysiloxane-polyether copolymer, 4 parts of dispersant, 1 part of fatty alcohol polyoxyethylene ether, and 60 parts of water, then adding 25 parts of stearate, and 2 parts of anti-adhesive B to continue stirring uniformly;

[0114] (3) adding 13 parts of silicone propylene resin emulsion to step (2) to continue stirring uniformly;

[0115] (4) Add 1 part of dicumyl peroxide and 1 part of N-acetylphenylhydrazine to step (3), stir evenly, and then grind to obtain.

[0116] The polysiloxane-polyether copolymer is byk 349.

[0117] The fatty alcohol polyoxyethylene ether has a CAS number of 111-09-3.

[0118] The dispersant is a combination of a polysiloxane copolymer dispersant and a lignosulfonate dispersant, and the polysiloxane copolymer dispersant is byk-P 104S.

[0119] The mass ratio of the polysiloxane copolymer dispersant and the lignosulfonate is 2:1.

[0120] The stearate is a combination of calcium stearate and zinc stearate.

[0121] The mass ratio of the calcium stearate and the zinc stearate is 1:2.5, and both are purchased from Henan Tuoyuan Chemical Product Co., Ltd.

[0122] The anti-sticking agent B is a combination of polytetrafluoroethylene wax and PDMS.

[0123] The mass ratio of the polytetrafluoroethylene wax and the PDMS is 0.6:1.

[0124] The polytetrafluoroethylene wax is purchased from Jiangsu Tianwen New Material Technology Co., Ltd., and the model is TW-F1011P.

[0125] The PDMS has a model of Dow Corning XIAMETER TM OFX-5330.

[0126] The solid content of the silicone-acrylic resin emulsion is 48±1wt%.

[0127] A preparation method of a special anti-blocking sandpaper for paint polishing, comprising the following steps:

[0128] (1) applying a first adhesive layer on a substrate;

[0129] (2) adsorbing modified abrasives on the substrate coated with the first adhesive layer by electrostatic sanding process;

[0130] (3) applying a second adhesive layer after drying step (2);

[0131] (4) applying an anti-blocking coating layer after drying and curing of step (3) to obtain.

[0132] The application amount of the first adhesive layer is 20g / m 2 .

[0133] The coating amount of the second adhesive layer is 60g / m 2 .

[0134] The coating amount of the anti-blocking coating layer is 40g / m 2 .

[0135] The drying temperature in the step (2) and step (3) is 70℃, and the drying time is 45min.

[0136] The curing temperature in the step (3) is 90℃, and the curing time is 5h.

[0137] Embodiment 2

[0138] Embodiment 2 provides an anti-blocking sandpaper special for paint polishing, which comprises, from bottom to top, a substrate, a first adhesive layer, an abrasive layer, a second adhesive layer and an anti-blocking coating layer.

[0139] The substrate is latex paper.

[0140] The first adhesive layer comprises, by mass fraction, modified resin 100 parts, ammonium chloride 1.5 parts, coupling agent 0.08 parts and leveling agent 0.08 parts.

[0141] The modified resin is melamine modified urea-formaldehyde resin.

[0142] The melamine modified urea-formaldehyde resin has a solid content of 80±2wt%, and a viscosity of 1000±100cps (30℃), and is purchased from Hangzhou Lin'an Funi Resin Co., Ltd.

[0143] The coupling agent is silane coupling agent.

[0144] The silane coupling agent is KH 560.

[0145] The leveling agent is silicone type leveling agent.

[0146] The silicone type leveling agent is polyether modified organosiloxane, and the model is BYK 349.

[0147] The preparation method of the first adhesive layer is as follows: the modified resin, ammonium chloride, coupling agent and leveling agent are uniformly mixed to obtain the first adhesive layer.

[0148] The abrasive layer is modified abrasive, and the modified abrasive comprises, by mass fraction, abrasive 100 parts, titanate coupling agent 1.5 parts, polyvinylpyrrolidone 2 parts, sodium dodecyl benzene sulfonate 1.5 parts and water 120 parts.

[0149] The abrasive is brown corundum.

[0150] The brown corundum is calcined brown corundum, which is purchased from Henan Yedax New Material Science and Technology Co., Ltd.

[0151] The average molecular weight of the polyvinylpyrrolidone is 40000, which is purchased from Yixing Biotech Co., Ltd.

[0152] The preparation method of the modified abrasive is as follows: the abrasive and water are uniformly mixed, then the titanium ester coupling agent, the polyvinylpyrrolidone, and the sodium dodecyl benzene sulfonate are added after the temperature is increased to 60℃, and then the stirring reaction is carried out for 2h, and then the centrifugal filtration and drying are carried out.

[0153] The raw materials of the second adhesive layer include, by mass fraction, melamine modified urea-formaldehyde resin 100 parts, ammonium chloride 1.5 parts, functional additives 15 parts, silane coupling agent 0.1 part, and acrylate type leveling agent 0.1 part.

[0154] The solid content of the melamine modified urea-formaldehyde resin is 80±2wt%, and the viscosity is 1000±100cps (30℃), which is purchased from Hangzhou Lin'an Funi Resin Co., Ltd.

[0155] The functional additives include anti-adhesive A, waterproof agent, and antistatic agent.

[0156] The mass ratio of the anti-adhesive A, the waterproof agent, and the antistatic agent is 6:7:7.

[0157] The anti-adhesive A is PDMS.

[0158] The PDMS is polyepoxy modified polydimethylsiloxane.

[0159] The viscosity of the polyepoxy modified polydimethylsiloxane is 1200cst, and the model is Dow Corning XIAMETER TM OFX-5330.

[0160] The waterproof agent is a combination of acrylic acid and fluorocarbon, and the fluorocarbon is purchased from Nanjing Quanxi Chemical Co., Ltd.

[0161] The mass ratio of the acrylic acid and the fluorocarbon is 1:3.

[0162] The antistatic agent is a combination of anionic antistatic agent and non-ionic antistatic agent.

[0163] The mass ratio of the anionic antistatic agent and the non-ionic antistatic agent is 6:3.

[0164] The anionic antistatic agent is a combination of alkali metal salt of alkyl sulfonic acid and alkali metal salt of fatty alcohol ether phosphate.

[0165] The mass ratio of the alkali metal salt of the alkyl sulfonic acid and the alkali metal salt of the fatty alcohol ether phosphate is 5:3, the alkali metal salt of the alkyl sulfonic acid is sodium alkyl sulfonate, model: Lanxess H95, Germany, the alkali metal salt of the fatty alcohol ether phosphate is potassium fatty alcohol ether phosphate, purchased from Haian Petroleum Chemical Factory in Jiangsu Province, model: MOA-3PK-70.

[0166] The non-ionic antistatic agent is an ethylene oxide amine addition antistatic agent, model: Clariant SAS93, Germany.

[0167] The preparation method of the second adhesive layer is as follows: uniformly mix melamine modified urea-formaldehyde resin, ammonium chloride, functional additives, silane coupling agent and acrylate type leveling agent according to mass fraction to obtain the second adhesive layer.

[0168] The preparation method of the anti-blocking coating layer is as follows:

[0169] (1) weigh each raw material according to mass fraction;

[0170] (2) uniformly stir 2 parts of polysiloxane-polyether copolymer, 4 parts of dispersant, 1 part of fatty alcohol polyoxyethylene ether and 60 parts of water, then add 25 parts of stearate, 2 parts of anti-adhesive B and continue to stir uniformly;

[0171] (3) add 13 parts of silicone propylene resin emulsion to step (2) and continue to stir uniformly;

[0172] (4) add 1 part of dicumyl peroxide and 1 part of N-acetylphenylhydrazine to step (3), stir uniformly and then grind to obtain the anti-blocking coating layer.

[0173] The model of the polysiloxane-polyether copolymer is BYK 349, Borchers.

[0174] The fatty alcohol polyoxyethylene ether has a CAS number of 111-09-3.

[0175] The dispersant is a combination of polysiloxane copolymer dispersant and lignosulfonate dispersant, and the model of the polysiloxane copolymer dispersant is BYK-P 104S, Borchers.

[0176] The mass ratio of the polysiloxane copolymer dispersant and the lignosulfonate is 2:1.

[0177] The stearate is a combination of calcium stearate and zinc stearate.

[0178] The mass ratio of the calcium stearate and the zinc stearate is 1:2.5, and both are purchased from Henan Tuoyuan Chemical Product Co., Ltd.

[0179] The anti-adhesive B is a combination of polytetrafluoroethylene wax and PDMS.

[0180] The mass ratio of the polytetrafluoroethylene wax and the PDMS is 0.6:1.

[0181] The polytetrafluoroethylene wax is purchased from Jiangsu Tianwen New Material Technology Co., Ltd., model: TW-F1011P.

[0182] The PDMS, model: Dow Corning XIAMETER TM OFX-5330

[0183] The solid content of the silicone-acrylic resin emulsion is 48±1wt%.

[0184] A preparation method of the special anti-blocking sandpaper for paint polishing, comprising the following steps:

[0185] (1) applying a first adhesive layer on a substrate;

[0186] (2) adsorbing modified abrasives on the substrate coated with the first adhesive layer by electrostatic sanding process;

[0187] (3) applying a second adhesive layer after drying of step (2);

[0188] (4) applying an anti-blocking coating layer after drying and curing of step (3) to obtain.

[0189] The application amount of the first adhesive layer is 20g / m 2 .

[0190] The application amount of the second adhesive layer is 60g / m 2 .

[0191] The application amount of the anti-blocking coating layer is 40g / m 2 .

[0192] The drying temperature in steps (2) and (3) is 70°C, and the drying time is 45min.

[0193] The curing time in step (3) is 90°C, and the curing time is 5h.

[0194] Comparative Example 1

[0195] Comparative Example 1 provides a special anti-blocking sandpaper for paint polishing, and the specific embodiment is the same as that of Example 1, except that the abrasive layer comprises 100 parts of abrasives by mass.

[0196] A preparation method of the special anti-blocking sandpaper for paint polishing, and the specific embodiment is the same as that of Example 1.

[0197] Comparative Example 2

[0198] The comparative example 2 provides a special anti-clogging sandpaper for paint polishing, which has the same implementation as the example 1 except that the mass ratio of the anti-sticking agent A, the waterproof agent and the antistatic agent is 2:2:7.

[0199] A preparation method of a special anti-clogging sandpaper for paint polishing, which has the same implementation as the example 1.

[0200] The comparative example 3

[0201] The comparative example 3 provides a special anti-clogging sandpaper for paint polishing, which has the same implementation as the example 1 except that the anionic antistatic agent is an alkali metal salt of alkyl sulfonic acid.

[0202] A preparation method of a special anti-clogging sandpaper for paint polishing, which has the same implementation as the example 1.

[0203] The comparative example 4

[0204] The comparative example 4 provides a special anti-clogging sandpaper for paint polishing, which has the same implementation as the example 1 except that the anti-sticking agent A is polyvinyl alcohol, CAS: 9002-89-5.

[0205] A preparation method of a special anti-clogging sandpaper for paint polishing, which has the same implementation as the example 1.

[0206] Performance test:

[0207] 1. Antistatic performance: The surface resistance of the sandpaper is measured by a surface resistance tester.

[0208] 2. Anti-clogging performance: Under the same conditions, the sandpaper is made into a 6-inch disc and used to grind PU material 5 times by a grinding tester to observe the surface dust adhesion.

[0209] 3. Water resistance: The sandpaper to be tested is immersed in water at 25°C and constant temperature water at 100°C respectively, and the time of glue layer whitening is recorded.

[0210] Test results:

[0211]

Claims

1. A type of anti-clogging sandpaper specifically for paint sanding, characterized in that, From bottom to top, it includes: a substrate, a first adhesive layer, an abrasive layer, a second adhesive layer, and an anti-clogging coating layer; The first adhesive layer, by weight, comprises the following raw materials: 80-120 parts of melamine-modified urea-formaldehyde resin, 1-2 parts of ammonium chloride, 0.05-1 part of coupling agent, and 0.05-1 part of leveling agent; The second adhesive layer, by weight, comprises the following raw materials: 80-120 parts of melamine-modified urea-formaldehyde resin, 1-2 parts of ammonium chloride, 10-20 parts of functional additives, 0.05-0.15 parts of silane coupling agent, and 0.05-0.15 parts of acrylate leveling agent; The melamine-modified urea-formaldehyde resin has a solid content of 60-85 wt% and a viscosity of 800-1200 cps. The functional additives include anti-adhesion agent A, waterproofing agent, and antistatic agent, wherein the mass ratio of anti-adhesion agent A, waterproofing agent, and antistatic agent is (4-7):(4-7):(4-7); The antistatic agent is a combination of anionic and nonionic antistatic agents; the anionic antistatic agent is a combination of alkali metal salts of alkyl sulfonic acids and alkali metal salts of fatty alcohol ether phosphates in a mass ratio of (5-8):(1-3), and the nonionic antistatic agent is an ethylene oxide amine adduct antistatic agent.

2. The anti-clogging sandpaper for paint sanding according to claim 1, characterized in that, The abrasive layer is a modified abrasive, and the modified abrasive, by mass, comprises: 90-110 parts abrasive, 1-2 parts titanate coupling agent, 2-3 parts polyvinylpyrrolidone, 1-2 parts sodium dodecylbenzenesulfonate, and 100-150 parts water.

3. The anti-clogging sandpaper for paint sanding according to claim 1, characterized in that, The method for preparing the anti-clogging coating layer is as follows: (1) Weigh each raw material according to parts by weight; (2) After mixing 1-3 parts of polysiloxane-polyether copolymer, 3-5 parts of dispersant, 0.5-2 parts of fatty alcohol polyoxyethylene ether, and 50-70 parts of water evenly, add 20-30 parts of stearate and 1-3 parts of anti-sticking agent B and continue mixing evenly. (3) Add 10-15 parts of silicone-acrylic resin emulsion to step (2) and continue stirring until homogeneous; (4) Add 0.5 to 2 parts of dicumyl peroxide and 0.5 to 2 parts of N-acetylphenylhydrazine to step (3), stir evenly and then grind to obtain the product.

4. A method for preparing anti-clogging sandpaper for paint sanding according to claim 1 or 2, characterized in that, Includes the following steps: (1) Apply the first adhesive layer to the substrate; (2) Modified abrasives are adsorbed onto a substrate coated with a first adhesive layer by electrostatic sand planting process; (3) Apply the second adhesive layer after drying in step (2); (4) After drying in step (3), apply an anti-clogging coating layer to obtain the product.

5. The method for preparing anti-clogging sandpaper for paint sanding according to claim 4, characterized in that, The coating amount of the first adhesive layer is 10-40 g / m². 2 The coating amount of the second adhesive layer is 30-120 g / m². 2 The coating amount of the anti-blocking coating layer is 20-120 g / m². 2 .

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