Soft emery cloth as well as preparation method and application thereof

Abstract

The invention discloses soft molding sand cloth as well as a preparation method and application thereof, and relates to the technical field of molds. The abrasive cloth comprises a cloth-based base material, a surface treatment layer, an adhesive layer, an abrasive material layer and a composite adhesive layer, the cloth-based base material comprises raw cloth and an impregnant, the warp and weft count of the raw cloth is 16-20, and the raw cloth is made of cotton and polyester; the surface treatment layer contains butyronitrile latex; the impregnated material contains polyvinyl alcohol, the viscosity of the polyvinyl alcohol is 20-26 mPas, and the alcoholysis degree of the polyvinyl alcohol is 86-89 mole%. The thickness of the prepared abrasive cloth is reduced, the strength and the toughness are kept, the sheet carrying amount of a flap wheel is high, butyronitrile latex is used for conducting surface treatment on a cloth base, the situation that adhesive emulsion completely permeates into the back face of the cloth base to affect adhesion of abrasive materials during coating can be prevented, the phenomenon that the abrasive cloth agglomerates and falls off in the using process is avoided, the bonding strength is improved, and the service life of the abrasive cloth is prolonged. And the stiffness and the obdurability of the abrasive cloth can ensure the synchronous consumption of the abrasive cloth and the abrasive material, so that the probability of sheet breakage and sheet flying in the grinding process is effectively reduced.

Description

Technical Field

[0001] The present application relates to the field of abrasive tools, and in particular to a soft emery cloth and a preparation method and application thereof. Background Art

[0002] Emery cloth refers to abrasives bonded to a flexible substrate using a binder. It is also called flexible abrasives. It consists of a cloth base and abrasives. The cloth base is usually made of pure cotton cloth, and the abrasive is made of ordinary brown corundum. It is mainly used to polish rust, paint or burrs on the surface of metal workpieces, as well as to polish the surface. It can also be used to polish non-metallic materials such as bone products. Figure 1 The picture shows a diaphragm wheel, which is made of hundreds of abrasive cloth sheets bonded together with resin. It is a type of abrasive cloth wheel and is suitable for large-area rough polishing, grinding, rust removal and grinding in industries such as heavy machinery, automobile manufacturing, ship repair, aluminum alloy, hardware and decoration, as well as polishing and shaping of irregular surfaces.

[0003] With the rapid development of manufacturing industry, manufacturers have higher and higher requirements for grinding and polishing, requiring abrasive tools to have a certain grinding life and reduce material costs. The existing abrasive cloth used for grinding and polishing of pipeline outer walls is prone to problems such as abrasive cloth breakage and flying pieces in the application of flap wheel products due to the insufficient strength of the abrasive cloth and the wear resistance of the abrasive, resulting in excessive consumption and non-wear resistance.

[0004] Moreover, the base of the emery cloth is generally made of pure cotton cloth. In order to ensure the strength of the emery cloth, the thickness is increased, which has the problem of high thickness, resulting in less flap wheel loading and poor synchronization. If the emery cloth is too thick, it may also cause excessive friction when the flap wheel is running, which will not only accelerate the wear of the emery cloth, but also cause excessive wear or damage to the processed material, affecting the processing quality and making it difficult to maintain processing accuracy and a good grinding life. Summary of the invention

[0005] The present application provides a soft emery cloth and a preparation method and application thereof. The thickness of the prepared emery cloth is reduced while the strength is maintained, which can increase the carrying capacity of the diaphragm wheel. The stiffness and toughness of the emery cloth can ensure the synchronous consumption of the cloth base and the abrasive, reduce the probability of broken and flying pieces during the grinding process, and improve the utilization rate and wear resistance of the emery cloth.

[0006] In order to solve the above technical problems, one of the purposes of the present application is to provide a soft emery cloth, comprising a cloth base material, a surface treatment layer, an adhesive layer, an abrasive layer and a rubber layer arranged in sequence, wherein the abrasive layer is formed by planting sand on the adhesive layer;

[0007] The cloth-based substrate comprises a raw cloth and an impregnated substance immersed in and dispersed in the raw cloth;

[0008] The warp yarn count of the original cloth is 16-20, the weft yarn count is 16-20, the warp yarn density is 105-125, the weft yarn density is 50-60, and the material of the original cloth is 15%-40% cotton and 60%-85% polyester;

[0009] The impregnated material includes polyvinyl alcohol, the viscosity of the polyvinyl alcohol is 20-26 mPas, and the alcoholysis degree is 86-89 mole%;

[0010] The surface treatment layer contains nitrile latex.

[0011] The present application optimizes the yarn count, density and cotton-polyester ratio of the cloth base material, which can reduce the thickness of the emery cloth while taking into account the strength of the emery cloth. When applied to the folding wheel product, the amount of carriers can be increased to avoid the wear of the processed material caused by the large friction caused by the emery cloth being too thick. The reduced thickness of the emery cloth can improve the precision of grinding and ensure the processing quality; the present application uses an impregnation containing polyvinyl alcohol for impregnation. The cotton material contained in the cloth base helps to provide faster moisture absorption and moisture retention, control the degree of alcoholysis and viscosity of polyvinyl alcohol, so that the polyvinyl alcohol gives the cloth base higher stiffness and toughness. When the emery cloth is ground and polished, the strength of the cloth base can improve the wear resistance, reduce the phenomenon of broken and flying pieces, improve the utilization rate of the emery cloth, and ensure that the cloth base can be consumed synchronously with the abrasive; the nitrile latex in the mixed emulsion is used to treat the cloth base surface, which can prevent the adhesive emulsion from completely penetrating into the back of the cloth base during coating and affecting the adhesion of the abrasive. The nitrile latex does not affect the stiffness and toughness of the cloth base, and can also ensure that the peeling strength between the cloth base material and the abrasive layer is high, effectively avoiding the phenomenon of sand clumping and falling during the use of the emery cloth, improving the grinding effect, and effectively improving the wear resistance of the emery cloth.

[0012] As a preferred embodiment of the soft emery cloth described in the present application, the alcoholysis degree and viscosity of the polyvinyl alcohol are tested according to JISK 6726-1994 standard.

[0013] As a preferred embodiment of the soft abrasive cloth described in the present application, the viscosity of the polyvinyl alcohol is measured by using a Brookfield type rotational viscometer at 20 degrees Celsius to measure a 4 wt % aqueous solution.

[0014] As a preferred embodiment of the soft abrasive cloth described in the present application, the raw material for preparing the surface treatment layer is a mixed emulsion, and the mixed emulsion includes the following components in parts by weight: 90-100 parts of nitrile latex and 2-10 parts of polyvinyl alcohol.

[0015] As a preferred embodiment of the soft abrasive cloth described in the present application, the raw material for preparing the adhesive layer is an adhesive emulsion, and the adhesive emulsion includes a phenolic resin.

[0016] As a preferred embodiment of the soft abrasive cloth described in the present application, the raw material for preparing the adhesive layer is an adhesive emulsion, and the adhesive emulsion includes the following components in parts by weight: 90-96 parts of phenolic resin, 0-2 parts of coupling agent and 4-10 parts of low melting point compound.

[0017] As a preferred embodiment of the soft abrasive cloth described in the present application, the adhesive emulsion comprises the following components in parts by weight: 90-95 parts of phenolic resin, 0.5-2 parts of coupling agent and 4-9 parts of low melting point compound.

[0018] As a preferred embodiment of the soft abrasive cloth described in the present application, the raw material for preparing the adhesive layer is adhesive latex, and the adhesive latex includes the following components in parts by weight: 54-75 parts of phenolic resin, 0-3 parts of coupling agent and 25-46 parts of low melting point compound.

[0019] As a preferred embodiment of the soft abrasive cloth described in the present application, the raw material for preparing the adhesive layer is adhesive latex, and the adhesive latex includes the following components in parts by weight: 54-74 parts of phenolic resin, 1-3 parts of coupling agent and 25-45 parts of low melting point compound.

[0020] The adhesive layer and the adhesive layer of the present application are added with low-melting-point compounds, which can provide heat dissipation in the grinding process, avoid the high friction heat generated by the emery cloth and the processed material, and cause carbonization of the cloth base. The carbonization of the cloth base will affect the surface processing quality of the processed material. The coupling agent is used to improve the dispersibility of the low-melting-point compound in the phenolic resin system to ensure the bonding strength.

[0021] As a preferred embodiment of the soft emery cloth described in the present application, the total solid content of the nitrile latex is 43%-55%, the viscosity is 30-200 mPas, and the surface tension is 27-45 Mn / m.

[0022] As a preferred embodiment of the soft abrasive cloth described in the present application, in the cloth-based substrate, the content of the impregnated substance in the original cloth is 20-30 g / m 2 .

[0023] As a preferred embodiment of the soft abrasive cloth described in the present application, the surface treatment layer is formed by a mixed emulsion, and the coating amount of the mixed emulsion is 30-50g / m 2 .

[0024] As a preferred embodiment of the soft emery cloth described in this application, the amount of abrasive sand is 200-800 g / m 2 The thickness of the adhesive layer is 40%-50% of the height of the abrasive basic particles after sand planting. After the abrasive is sand planted, the coating amount of the raw material prepared in the adhesive layer can be determined by observing the thickness ratio of the adhesive layer on the sandpaper after curing and the abrasive basic particles under a microscope.

[0025] As a preferred solution of the soft abrasive cloth described in the present application, the adhesive layer accounts for 50wt%-70wt% of the mass of the adhesive layer.

[0026] As a preferred embodiment of the soft emery cloth described in the present application, when the warp yarn count of the original cloth is 16-17 and the weft yarn count is 16-17, the material of the original cloth is 15%-25% cotton and 75%-85% polyester; when the warp yarn count of the original cloth is 17-18 and the weft yarn count is 17-18, the material of the original cloth is 25%-30% cotton and 70%-75% polyester; when the warp yarn count of the original cloth is 18-20 and the weft yarn count is 18-20, the material of the original cloth is 30%-40% cotton and 60%-70% polyester.

[0027] The inventors have found through experiments that the emery cloth base of the present application can ensure the toughness of the emery cloth base by controlling the yarn count and the cotton-polyester ratio within the above-mentioned preferred range, while reducing the thickness of the emery cloth base, ensuring the synchronous consumption of the emery cloth and the abrasive, and improving the grinding process quality.

[0028] As a preferred embodiment of the soft abrasive cloth described in the present application, the coupling agent is at least one of a silane coupling agent, a titanate coupling agent, an aluminate coupling agent, a borate coupling agent, a phosphate coupling agent, a carboxylic acid coupling agent and an amino coupling agent.

[0029] As a preferred embodiment of the soft abrasive cloth described in the present application, the low melting point compound in the composite emulsion and the low melting point compound in the adhesive emulsion are independently selected from at least one of cryolite, potassium fluoroborate, zinc stearate, calcium stearate, graphite, fluorite and molybdenum disulfide.

[0030] As a preferred embodiment of the soft abrasive cloth described in the present application, the mesh size of the low melting point compound is 100-1000 mesh.

[0031] As a preferred embodiment of the soft abrasive cloth described in the present application, the mesh size of the low melting point compound is 200-500 mesh.

[0032] As a preferred embodiment of the soft emery cloth described in the present application, the mass percentage of free formaldehyde in the phenolic resin in the adhesive latex and the composite latex is 0.19%-0.28%, and the mass percentage of free phenol is 8.67%-10%.

[0033] As a preferred embodiment of the soft emery cloth described in the present application, the free formaldehyde of the phenolic resin is tested according to the GB / T32684-2016 standard, and the free phenol of the phenolic resin is tested according to the GB / T 30773-2014 standard.

[0034] The phenolic resin in the adhesive layer and the adhesive layer of the present application plays an important role in the bonding strength between the abrasive and the cloth base. The inventors have found through experiments that controlling the free formaldehyde and free phenol of the phenolic resin within the above-mentioned range can effectively improve the bonding strength of the emery cloth, especially for the case where the adhesive layer contains low-melting point compounds, which can ensure that the peel strength of the prepared emery cloth is at a high level, while effectively improving the heat dissipation effect during the grinding process.

[0035] As a preferred embodiment of the soft abrasive cloth described in the present application, the abrasive of the abrasive layer is at least one of corundum, zirconium corundum, brown corundum, calcined brown corundum, white corundum, ceramic corundum, silicon carbide and aluminum oxide.

[0036] As a preferred embodiment of the soft abrasive cloth described in the present application, the abrasive is calcined brown corundum, and the secondary calcination temperature of the calcined brown corundum is 1200°C-1600°C.

[0037] As a preferred embodiment of the soft emery cloth described in the present application, the abrasive particle size number is 40-400#, and the basic particle size of the abrasive is 20-500 μm.

[0038] The particle size number of the abrasive is obtained through screening. For example, the particle size range of particle size 70# is between 212-250. This range includes coarse particles, basic particles and fine particles. The basic particles are the particles on the lower inspection sieve.

[0039] The abrasive material of the emery cloth in this application is calcined brown corundum. By processing traditional brown corundum at high temperature to separate or evaporate the impurities therein, it becomes purer and has a rougher surface, and is therefore more hydrophilic. The microcracks generated by bridging during the crushing process also further enhance its toughness and strength, effectively improving the wear resistance of the emery cloth.

[0040] As a preferred embodiment of the soft emery cloth described in the present application, the thickness of the soft emery cloth is less than 1 mm.

[0041] As a preferred embodiment of the soft emery cloth described in the present application, the thickness of the soft emery cloth is 0.5 mm-1 mm.

[0042] In order to solve the above technical problems, the second object of the present application provides a method for preparing a soft emery cloth, comprising the following steps:

[0043] (1) The original fabric is impregnated with an impregnation emulsion, and the glue is pressed into the original fabric using a roller, followed by drying to form a fabric-based substrate; the impregnation emulsion comprises 20 wt % to 30 wt % of polyvinyl alcohol and the remainder is water;

[0044] (2) applying the raw materials for preparing the surface treatment layer to one side of the cloth base material for surface coating treatment, and drying to form the surface treatment layer;

[0045] (3) coating the raw material for preparing the adhesive layer on the surface of the surface treatment layer, and applying sanding with abrasive on the raw material for preparing the adhesive layer, and drying and curing the raw material to form an adhesive layer and an abrasive layer;

[0046] (4) coating the raw materials for preparing the size layer on the surface of the abrasive layer, drying and completely curing the abrasive layer to form the size layer;

[0047] (5) The obtained product is flexibly bent to obtain a finished emery cloth.

[0048] As a preferred embodiment of the method for preparing the soft abrasive cloth described in the present application, in step (1), the drying temperature is 120-150° C., and the drying is performed until the moisture content is below 2%.

[0049] As a preferred embodiment of the method for preparing the soft abrasive cloth described in the present application, in step (1), the cloth is dried to a moisture content between 0.5% and 1.5%.

[0050] As a preferred embodiment of the method for preparing the soft abrasive cloth described in the present application, in step (2), the drying temperature is 135-145° C. and the drying time is 2-3 min.

[0051] As a preferred embodiment of the method for preparing the soft abrasive cloth described in the present application, in step (3), the sand planting gap during the sand planting process is 20-35 mm, the substrate running speed is 22-25 m / min, the voltage is 38-40 KV, and the frequency is 6-8 Hz.

[0052] As a preferred embodiment of the method for preparing the soft abrasive cloth described in the present application, in step (3), the drying temperature is 120-150° C. and the drying time is 60-120 min.

[0053] As a preferred embodiment of the method for preparing the soft abrasive cloth described in the present application, in step (3), the amount of sand is 200-800 g / m 2 The raw material for preparing the adhesive layer is adhesive emulsion, and the mass of the abrasive is 2.5-3 times the coating amount of the adhesive emulsion.

[0054] As a preferred embodiment of the method for preparing the soft abrasive cloth described in the present application, in step (3), the sand planting is gravity sand planting or electrostatic sand planting.

[0055] As a preferred embodiment of the method for preparing the soft abrasive cloth described in the present application, in step (4), the raw material for preparing the composite glue layer is composite glue latex, the raw material for preparing the adhesive layer is adhesive latex, and the coating amount of the composite glue latex is 50-70% of the coating mass of the adhesive latex.

[0056] As a preferred embodiment of the method for preparing the soft abrasive cloth described in the present application, in step (4), the drying temperature is 130° C. and the drying time is 120-240 min.

[0057] As a preferred embodiment of the method for preparing the soft abrasive cloth described in the present application, in step (5), the bending directions are 45° and 90°, the bending knife diameter is 20-30 mm, and the bending pressure is 4-6 bar.

[0058] In order to solve the above-mentioned technical problems, the third purpose of the present application provides an application of a soft abrasive cloth in the preparation of a diaphragm wheel product. The base thickness of the abrasive cloth prepared in the present application is reduced, and the strength is simultaneously maintained at a high level, so that the overall thickness of the abrasive cloth is thinner, which can increase the amount of film carried in subsequent applications of the diaphragm wheel product. The lower thickness of the abrasive cloth can reduce the wear on the processed material and improve the processing precision.

[0059] Compared with the prior art, this application has the following beneficial effects:

[0060] 1. This application controls the yarn count, density and cotton-polyester ratio of the cloth-based substrate within a specific range, which can reduce the thickness of the emery cloth while taking into account the strength of the emery cloth. When applied to diaphragm wheel products, the amount of carriers can be increased to avoid the wear of the processed material caused by excessive friction due to the thickness of the emery cloth. The higher strength of the emery cloth can reduce the imagination of broken and flying pieces, and the reduced thickness of the emery cloth can improve the precision of grinding and ensure the processing quality.

[0061] 2. When the present application uses an impregnant containing polyvinyl alcohol for impregnation, the degree of alcoholysis of the polyvinyl alcohol is controlled so that the polyvinyl alcohol gives the cloth base higher strength and toughness. When the emery cloth is ground and polished, the wear resistance is ensured, the phenomenon of broken pieces and flying pieces is reduced, the utilization rate of the emery cloth is improved, and the stiffness of the cloth base is ensured so that it can be consumed synchronously with the abrasive.

[0062] 3. The present application pre-treats the surface of the cloth base with nitrile latex in the mixed emulsion, which can prevent the adhesive emulsion from completely penetrating into the back of the cloth base and affecting the adhesion of the abrasive when applied. The nitrile latex does not affect the stiffness and strength of the cloth base, and can also ensure that the peeling strength between the cloth base material and the abrasive layer is high, effectively avoiding the phenomenon of sand clumping during the use of the emery cloth, improving the grinding effect, and effectively improving the wear resistance of the emery cloth. BRIEF DESCRIPTION OF THE DRAWINGS

[0063] Figure 1 :Product picture of a flap wheel assembled with several abrasive cloths. DETAILED DESCRIPTION

[0064] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0065] The following Table 1 shows the sources and types of raw materials used in the examples and comparative examples of the present application. Unless otherwise specified, the raw materials used can be obtained commercially, and the same raw materials are used in parallel experiments.

[0066] Table 1 - Sources of raw materials used in the examples and comparative examples of this application

[0067]

[0068] Example 1

[0069] A soft emery cloth comprises a cloth base material, a surface treatment layer, an adhesive layer, an abrasive layer and a rubber layer, wherein the cloth base material comprises an original cloth and an impregnated substance immersed in and dispersed in the original cloth, one side of the cloth base material is coated with a mixed emulsion to form a surface treatment layer, one side of the surface treatment layer is coated with an adhesive emulsion to form an adhesive layer, an abrasive is embedded in the adhesive layer to form an abrasive layer, a rubber emulsion is coated on the surface of the abrasive layer to form a rubber layer, and the abrasive of the abrasive layer is calcined brown corundum; and a preparation method thereof comprises the following steps:

[0070] (1) selecting warp yarn and weft yarn with a count of 18 to blend into a base fabric, wherein the cotton-polyester ratio of the yarn count is 25 wt% cotton and 75 wt% polyester, and the warp and weft density of the original fabric is 115*60;

[0071] (2) The original cloth is completely soaked with the impregnation emulsion, and then the adhesive is completely pressed into the cloth base using pressure rollers on both sides, and then baked at 130°C until the moisture content is below 1%. The impregnation emulsion is 25wt% polyvinyl alcohol A and 75wt% water. After drying, the amount of polyvinyl alcohol A is calculated to be 24g / m 2 ;

[0072] (3) Use the mixed emulsion to coat the front side of the cloth base for subsequent bonding of the abrasive, with a coating amount of 40g / m 2 , the mixed emulsion includes 95wt% of nitrile latex A and 5wt% of polyvinyl alcohol A, and is dried at a temperature of 140°C for 3min;

[0073] (4) Apply adhesive emulsion on the front of the cloth base, and bond the abrasive on the adhesive emulsion by electrostatic sand planting. The sand planting gap is 25 mm, the substrate running speed is 24 m / min, the voltage is 40 KV, the frequency is 8 Hz, and the sand planting amount is 600 g / m 2 , the coating amount of adhesive emulsion is 220g / m 2At this time, the thickness of the adhesive emulsion is between 40% and 50% of the height of the basic abrasive particles after sand planting. The adhesive emulsion includes 95wt% phenolic resin A, 1wt% coupling agent and 4wt% cryolite. The abrasive is calcined brown corundum with a secondary calcination temperature of 1400°C, a particle size of 70#, and a basic particle size of 212-250μm.

[0074] Among them, the viscosity of polyvinyl alcohol A is 20.5-24.5mPas, and the alcoholysis degree is 87-89 mole%; the free formaldehyde of phenolic resin A is 0.19%, and the free phenol is 10%;

[0075] (5) baking the semi-finished abrasive cloth at 130° C., and applying a rubber latex on the surface of the abrasive, wherein the rubber latex is 50 wt % of the mass of the adhesive latex, and the rubber latex comprises 54 wt % of phenolic resin A, 3 wt % of a coupling agent, and 43 wt % of cryolite;

[0076] (6) After the emery cloth is baked at 130°C, it is heat-wound into a roll in the reverse direction with the abrasive surface facing outward, and then baked until the resin is completely cured. The resulting product is mechanically bent in the bending directions of 45° and 90°, with a bending knife diameter of 25 mm and a bending pressure of 5 bar to obtain a finished emery cloth.

[0077] Through experimental observation, the abrasive cloth of Example 1 did not show obvious clumping and sand shedding phenomenon during the flexible bending preparation process. The abrasive cloth of Example 1 was made into a diaphragm wheel with an outer diameter of 300 mm and an abrasive cloth length of 62.5 mm. No obvious sand collapse occurred when the diaphragm wheel was punched. The total number of abrasive cloth assembled in the diaphragm wheel was 1475. When the diaphragm wheel was used for grinding and polishing of steel pipes, it was ground until the weld bar could not be effectively ground to a flat surface. No abrasive cloth breakage or flying pieces occurred during the process. The remaining abrasive cloth length of the diaphragm wheel after grinding was detected to be 4.8 mm, the grinding time was 2212 min, the abrasive cloth utilization rate was 92.32%, and the abrasive cloth wear resistance was 39.9.

[0078] Among them, the utilization rate of abrasive cloth = (initial abrasive cloth length of the diaphragm wheel - remaining abrasive cloth length after grinding) / initial abrasive cloth length of the diaphragm wheel * 100%. The utilization rate of abrasive cloth reflects the utilization capacity of abrasive cloth during the use of the diaphragm wheel. The higher the utilization rate, the less abrasive cloth waste.

[0079] Among them, the wear resistance of the emery cloth = the initial length of the emery cloth of the diaphragm wheel * the minutes of use / [(the initial length of the emery cloth of the diaphragm wheel - the remaining length of the emery cloth after grinding) * 60min]. The wear resistance of the emery cloth reflects the grinding ability of the diaphragm wheel during use. Under the condition of ensuring the grinding effect, the higher the wear resistance, the longer the diaphragm wheel can be used, and the same diaphragm wheel can grind more products.

[0080] Example 2

[0081] A soft emery cloth comprises a cloth base material, a surface treatment layer, an adhesive layer, an abrasive layer and a rubber layer, wherein the cloth base material comprises an original cloth and an impregnated substance immersed in and dispersed in the original cloth, one side of the cloth base material is coated with a mixed emulsion to form a surface treatment layer, one side of the surface treatment layer is coated with an adhesive emulsion to form an adhesive layer, an abrasive is embedded in the adhesive layer to form an abrasive layer, a rubber emulsion is coated on the surface of the abrasive layer to form a rubber layer, and the abrasive of the abrasive layer is calcined brown corundum; and a preparation method thereof comprises the following steps:

[0082] (1) selecting warp yarn and weft yarn with a count of 16 to blend into a base fabric, wherein the cotton-polyester ratio of the yarn count is 20 wt% cotton and 80 wt% polyester, and the warp and weft density of the original fabric is 105*50;

[0083] (2) The cloth base is completely impregnated with the impregnation emulsion, and then the adhesive is completely pressed into the cloth base using pressure rollers on both sides, and then baked at 130°C until the moisture content is below 1%. The impregnation emulsion is 25wt% polyvinyl alcohol A and 75wt% water. After drying, the amount of polyvinyl alcohol A is calculated to be 26g / m 2 ;

[0084] (3) Use the mixed emulsion to coat the front side of the cloth base for subsequent bonding of the abrasive, with a coating amount of 40g / m 2 , the mixed emulsion includes 98wt% of nitrile latex A and 2wt% of polyvinyl alcohol A, and is dried at a temperature of 140°C for 3min;

[0085] (4) Apply adhesive emulsion on the front of the cloth base, and bond the abrasive on the adhesive emulsion by electrostatic sand planting. The sand planting gap is 20 mm, the substrate running speed is 22 m / min, the voltage is 38 KV, the frequency is 6 Hz, and the sand planting amount is 550 g / m 2 , the adhesive latex coating amount is 200g / m 2 At this time, the thickness of the adhesive emulsion is between 40% and 50% of the height of the basic abrasive particles after sand planting. The adhesive emulsion includes 93wt% phenolic resin A, 1wt% coupling agent and 6wt% cryolite. The abrasive is calcined brown corundum with a secondary calcination temperature of 1400°C, a particle size of 70#, and a basic particle size of 212-250μm.

[0086] Among them, the viscosity of polyvinyl alcohol A is 20.5-24.5mPas, and the alcoholysis degree is 87-89 mole%; the free formaldehyde of phenolic resin A is 0.19%, and the free phenol is 10%;

[0087] (5) baking the semi-finished emery cloth, and applying a rubber latex on the surface of the abrasive, wherein the rubber latex is 60 wt % of the mass of the adhesive latex, and the rubber latex includes 65 wt % of phenolic resin A, 2 wt % of a coupling agent, and 33 wt % of cryolite;

[0088] (6) After the emery cloth is baked at 130°C, it is heat-wound into a roll in the reverse direction with the abrasive surface facing outward, and then baked until the resin is completely cured. The bending directions are 45° and 90°, the bending knife diameter is 25 mm, and the bending pressure is 5 bar, thereby obtaining a finished emery cloth.

[0089] Through experimental observation, the abrasive cloth of Example 2 did not show obvious clumping and sand shedding phenomenon during the flexible bending preparation process. The abrasive cloth of Example 2 was made into a diaphragm wheel with an outer diameter of 300mm and an abrasive cloth length of 62.5mm. No obvious sand collapse occurred when the diaphragm wheel was punched. The total number of abrasive cloth assembled in the diaphragm wheel was 1489 pieces. When the diaphragm wheel was used for grinding and polishing of steel pipes, it was ground until the weld bar could not be effectively ground to a flat surface. No abrasive cloth breakage or flying pieces occurred during the process. The remaining abrasive cloth length of the diaphragm wheel after grinding was detected to be 5.2mm, the grinding time was 2422min, the abrasive cloth utilization rate was 91.7%, and the abrasive cloth wear resistance was 44.03.

[0090] Example 3

[0091] A soft emery cloth comprises a cloth base material, a surface treatment layer, an adhesive layer, an abrasive layer and a rubber layer, wherein the cloth base material comprises an original cloth and an impregnated substance immersed in and dispersed in the original cloth, one side of the cloth base material is coated with a mixed emulsion to form a surface treatment layer, one side of the surface treatment layer is coated with an adhesive emulsion to form an adhesive layer, an abrasive is embedded in the adhesive layer to form an abrasive layer, a rubber emulsion is coated on the surface of the abrasive layer to form a rubber layer, and the abrasive of the abrasive layer is calcined brown corundum; and a preparation method thereof comprises the following steps:

[0092] (1) selecting warp yarn and weft yarn with a count of 20 for blending to form a base fabric, wherein the cotton-polyester ratio of the yarn count is 35wt% cotton and 65wt% polyester, and the warp and weft density of the original fabric is 125*55;

[0093] (2) The cloth base is completely impregnated with the impregnation emulsion, and then the adhesive is completely pressed into the cloth base using pressure rollers on both sides, and then baked at 130°C until the moisture content is below 1%. The impregnation emulsion is 25wt% polyvinyl alcohol A and 75wt% water. After drying, the amount of polyvinyl alcohol A is calculated to be 22g / m 2 ;

[0094] (3) Use the mixed emulsion to coat the front side of the cloth base for subsequent bonding of the abrasive, with a coating amount of 40g / m 2 , the mixed emulsion includes 96wt% of nitrile latex A and 4wt% of polyvinyl alcohol A, and is dried at a temperature of 140°C for 3min;

[0095] (4) Apply adhesive emulsion on the front of the cloth base, and bond the abrasive on the adhesive emulsion by electrostatic sand planting. The sand planting gap is 35mm, the substrate running speed is 25m / min, the voltage is 39KV, the frequency is 7Hz, and the sand planting amount is 700g / m 2 , the adhesive latex coating amount is 280g / m 2 At this time, the thickness of the adhesive emulsion is between 40% and 50% of the height of the basic abrasive particles after sand planting. The adhesive emulsion includes 90wt% phenolic resin A, 2wt% coupling agent and 8wt% cryolite. The abrasive is calcined brown corundum with a secondary calcination temperature of 1400°C, a particle size of 70#, and a basic particle size of 212-250μm.

[0096] Among them, the viscosity of polyvinyl alcohol A is 20.5-24.5mPas, and the alcoholysis degree is 87-89 mole%; the free formaldehyde of phenolic resin A is 0.19%, and the free phenol is 10%;

[0097] (5) baking the semi-finished emery cloth, and applying a rubber latex on the surface of the abrasive, wherein the rubber latex is 70 wt % of the mass of the adhesive latex, and the rubber latex includes 73 wt % of phenolic resin A, 2 wt % of a coupling agent, and 25 wt % of cryolite;

[0098] (6) After the emery cloth is baked at 130°C, it is heat-wound into a roll in the reverse direction with the abrasive surface facing outward, and then baked until the resin is completely cured. The bending directions are 45° and 90°, the bending knife diameter is 25 mm, and the bending pressure is 5 bar, thereby obtaining a finished emery cloth.

[0099] Through experimental observation, the abrasive cloth of Example 3 did not show obvious clumping and sand shedding phenomenon during the flexible bending preparation process. The abrasive cloth of Example 3 was made into a diaphragm wheel with an outer diameter of 300mm and an abrasive cloth length of 62.5mm. No obvious sand collapse phenomenon occurred when the diaphragm wheel was punched. The total number of abrasive cloth assembled in the diaphragm wheel was 1436. When the diaphragm wheel was used for grinding and polishing of steel pipes, it was ground until the weld bar could not be effectively ground to a flat surface. No abrasive cloth breakage or flying pieces occurred during the process. The remaining abrasive cloth length of the diaphragm wheel after grinding was detected to be 3.4mm. The grinding time was 2305min, the abrasive cloth utilization rate was 94.56%, and the abrasive cloth wear resistance was 40.6.

[0100] Example 4

[0101] A soft emery cloth, wherein the steps of the preparation method and the reagents, equipment and process parameters used in the steps are the same as those in Example 2, except that in steps (4) and (5), phenolic resin A is replaced by phenolic resin B in equal amounts, and the free formaldehyde content of phenolic resin B is 0.28% and the free phenol content is 8.67%.

[0102] Through experimental observation, the abrasive cloth of Example 4 did not show obvious clumping and sand shedding phenomenon during the flexible bending preparation process. The abrasive cloth of Example 4 was made into a diaphragm wheel with an outer diameter of 300 and an abrasive cloth length of 62.5 mm. A small amount of sand collapse occurred when the diaphragm wheel was punched. The total number of abrasive cloth assembled in the diaphragm wheel was 1422 pieces. When the diaphragm wheel was used for grinding and polishing of steel pipes, it was ground until the weld bar could not be effectively ground to a flat surface. No abrasive cloth breakage or flying pieces occurred during the process. The remaining abrasive cloth length of the diaphragm wheel after grinding was detected to be 6.2 mm, the grinding time was 1936 min, the abrasive cloth utilization rate was 90.1%, and the abrasive cloth wear resistance was 35.82.

[0103] Example 5

[0104] A soft emery cloth, wherein each step of the preparation method and the reagents, equipment and process parameters used in each step are the same as those in Example 2, except that in step (4), the adhesive emulsion is phenolic resin A, and cryolite is not added.

[0105] Through experimental observation, the abrasive cloth of Example 5 did not show obvious clumping and sand shedding phenomenon during the flexible bending preparation process. The abrasive cloth of Example 5 was made into a flap wheel with an outer diameter of 300mm and an abrasive cloth length of 62.5mm. No obvious sand collapse phenomenon occurred when the flap wheel was punched. The total number of abrasive cloth assembled in the flap wheel was 1499 pieces. When the flap wheel was used for grinding and polishing of steel pipes, it was ground until the weld bar could not be effectively ground to a flat surface. During the process, the flap wheel showed obvious blackening and slipping of the abrasive cloth. The remaining abrasive cloth length of the flap wheel after grinding was detected to be 18mm, the grinding time was 1395min, the abrasive cloth utilization rate was 71.2%, and the abrasive cloth wear resistance was 32.6.

[0106] Example 6

[0107] A soft emery cloth, wherein each step of the preparation method and the reagents, equipment and process parameters used in each step are the same as those in Example 4, except that in step (4), the adhesive emulsion is phenolic resin B, and cryolite is not added.

[0108] Through experimental observation, the abrasive cloth of Example 6 did not show obvious clumping and sand shedding phenomenon during the flexible bending preparation process. The abrasive cloth of Example 6 was made into a diaphragm wheel with an outer diameter of 300mm and an abrasive cloth length of 62.5mm. No obvious sand collapse occurred when the diaphragm wheel was punched. The total number of abrasive cloth assembled in the diaphragm wheel was 1513. When the diaphragm wheel was used for grinding and polishing of steel pipes, it was ground until the weld bar could not be effectively ground to a flat surface. During the process, the diaphragm on the diaphragm wheel obviously showed blackening and slipping. The remaining abrasive cloth length of the diaphragm wheel after grinding was detected to be 16.5mm, the grinding time was 1467min, the abrasive cloth utilization rate was 73.6%, and the abrasive cloth wear resistance was 33.2.

[0109] Example 7

[0110] A soft emery cloth, wherein the steps of the preparation method and the reagents, equipment and process parameters used in the steps are the same as those in Example 2, except that in steps (2) and (3), polyvinyl alcohol A is replaced by polyvinyl alcohol B in an equal amount, and the viscosity of polyvinyl alcohol B is 21-26 mPas and the degree of alcoholysis is 87-89 mole%.

[0111] Through experimental observation, the abrasive cloth of Example 7 did not show obvious clumping and sand shedding phenomenon during the flexible bending preparation process. The abrasive cloth of Example 7 was made into a flap wheel with an outer diameter of 300mm and an abrasive cloth length of 62.5mm. No obvious sand collapse phenomenon occurred when the flap wheel was punched. The total number of abrasive cloth assembled in the flap wheel was 1446. When the flap wheel was used for grinding and polishing of steel pipes, it was ground until the weld bar could not be effectively ground to a flat surface. No abrasive cloth breakage or flying pieces occurred during the process. The remaining abrasive cloth length of the flap wheel after grinding was detected to be 5.5mm, the grinding time was 2316min, the abrasive cloth utilization rate was 91.2%, and the abrasive cloth wear resistance was 42.3.

[0112] Example 8

[0113] A soft emery cloth, wherein the steps of the preparation method and the reagents, equipment and process parameters used in the steps are the same as those in Example 2, except that in steps (2) and (3), polyvinyl alcohol A is replaced by polyvinyl alcohol C in an equal amount, and the viscosity of polyvinyl alcohol C is 21-26 mPas and the degree of alcoholysis is 86-89 mole%.

[0114] Through experimental observation, the abrasive cloth of Example 8 did not show obvious clumping and sand shedding phenomenon during the flexible bending preparation process. The abrasive cloth of Example 8 was made into a flap wheel with an outer diameter of 300mm and an abrasive cloth length of 62.5mm. No obvious sand collapse phenomenon occurred when the flap wheel was punched. The total number of abrasive cloth assembled in the flap wheel was 1472 pieces. When the flap wheel was used for grinding and polishing of steel pipes, it was ground until the weld bar could not be effectively ground to a flat surface. No abrasive cloth breakage or flying pieces occurred in the process. The remaining abrasive cloth length of the flap wheel after grinding was detected to be 6.2mm, the grinding time was 2407min, the abrasive cloth utilization rate was 90%, and the abrasive cloth wear resistance was 44.5.

[0115] Example 9

[0116] A soft emery cloth, wherein each step of the preparation method and the reagents, equipment and process parameters used in each step are the same as those in Example 2, except that in step (3), the mixed emulsion includes 98 wt% of nitrile latex B and 2 wt% of polyvinyl alcohol A.

[0117] Through experimental observation, the abrasive cloth of Example 9 did not show obvious clumping and sand shedding phenomenon during the flexible bending preparation process. The abrasive cloth of Example 9 was made into a diaphragm wheel with an outer diameter of 300 mm and an abrasive cloth length of 62.5 mm. No obvious sand collapse occurred when the diaphragm wheel was punched. The total number of abrasive cloth assembled in the diaphragm wheel was 1416. When the diaphragm wheel was used for grinding and polishing of steel pipes, it was ground until the weld bar could not be effectively ground to a flat surface. No abrasive cloth breakage or flying pieces occurred during the process. The remaining abrasive cloth length of the diaphragm wheel after grinding was detected to be 6.5 mm, the grinding time was 2243 min, the abrasive cloth utilization rate was 89.6%, and the abrasive cloth wear resistance was 41.7.

[0118] Example 10

[0119] A soft emery cloth, wherein each step of the preparation method and the reagents, equipment and process parameters used in each step are the same as those in Example 2, except that in step (3), the mixed emulsion is nitrile latex A.

[0120] Through experimental observation, the abrasive cloth of Example 10 did not show obvious clumping and sand shedding phenomenon during the flexible bending preparation process. The abrasive cloth of Example 10 was made into a diaphragm wheel with an outer diameter of 300mm and an abrasive cloth length of 62.5mm. No obvious sand collapse phenomenon occurred when the diaphragm wheel was punched. The total number of abrasive cloth assembled in the diaphragm wheel was 1458 pieces. When the diaphragm wheel was used for grinding and polishing of steel pipes, it was ground until the weld bar could not be effectively ground to a flat surface. No abrasive cloth breakage or flying pieces occurred during the process. However, since polyvinyl alcohol was not added to the surface treatment layer, the cloth base was too soft and did not have sufficient stiffness. The cloth base and abrasive consumption were not synchronized. After grinding, the object to be ground had obvious incomplete grinding of weld scars, and grinding was required to achieve the expected grinding effect. The remaining abrasive cloth length of the diaphragm wheel after grinding was detected to be 3.4-11.6mm, and the grinding time was 1275min. The utilization rate and wear resistance of the abrasive cloth were not calculated due to the uneven grinding surface of the cloth.

[0121] Embodiment 11

[0122] A soft emery cloth, wherein the steps of the preparation method and the reagents, equipment and process parameters used in the steps are the same as those in Example 2, except that in step (4), calcined brown corundum is replaced by ordinary brown corundum, the particle size number is 70#, and the basic particle size is 212-250 μm.

[0123] Through experimental observation, the abrasive cloth of Example 11 did not show obvious clumping and sand shedding phenomenon during the flexible bending preparation process. The abrasive cloth of Example 11 was made into a diaphragm wheel with an outer diameter of 300 mm and an abrasive cloth length of 62.5 mm. No obvious sand collapse occurred when the diaphragm wheel was punched. The total number of abrasive cloth assembled in the diaphragm wheel was 1426. When the diaphragm wheel was used for grinding and polishing of steel pipes, it was ground until the weld bar could not be effectively ground to a flat surface. No abrasive cloth breakage or flying flakes occurred during the process. The remaining abrasive cloth length of the diaphragm wheel after grinding was detected to be 3.2 mm, the grinding time was 1847 min, the abrasive cloth utilization rate was 94.88%, and the abrasive cloth wear resistance was 32.44. Compared with Example 2, ordinary brown corundum is easily broken, resulting in reduced wear resistance.

[0124] Comparative Example 1

[0125] A soft emery cloth, wherein the steps of the preparation method and the reagents, equipment and process parameters used in the steps are the same as those in Example 2, except that in step (1), warp yarn and weft yarn with a count of 13 are selected for blending to form a base cloth, the cotton-polyester ratio of the yarn count is 50wt% cotton and 50wt% polyester, and the warp and weft density of the original cloth is 84*50.

[0126] After experimental observation, the sandpaper of comparative example 1 did not show obvious clumping and sand falling phenomenon during the flexible bending preparation process. The sandpaper of comparative example 1 was made into a diaphragm wheel with an outer diameter of 300mm and an sandpaper length of 62.5mm. There was no obvious sand collapse when the diaphragm wheel was punching. The total number of sandpaper assembled in the diaphragm wheel was 515 pieces. When the diaphragm wheel was used for grinding and polishing of steel pipes, the sandpaper broke after 32 minutes of use. The number of broken and flying pieces of the diaphragm wheel after grinding was detected to be 82 pieces, accounting for 16%. The remaining sandpaper length was 58.1mm, the sandpaper utilization rate was 7.0%, and the sandpaper wear resistance was 7.58.

[0127] Comparative Example 2

[0128] A soft emery cloth, wherein the steps of the preparation method and the reagents, equipment and process parameters used in the steps are the same as those in Example 2, except that in step (1), a warp yarn count of 11 and a weft yarn count of 16 are selected for blending to form a base cloth, the cotton-polyester ratio of the yarn count is 65wt% cotton and 35wt% polyester, and the warp and weft density of the original cloth is 83*50.

[0129] After experimental observation, the sandpaper of comparative example 2 did not show obvious clumping and sand shedding phenomenon during the flexible bending preparation process. The sandpaper of comparative example 2 was made into a diaphragm wheel with an outer diameter of 300mm and an sandpaper length of 62.5mm. No obvious sand collapse occurred when the diaphragm wheel was punched. The total number of sandpaper assembled in the diaphragm wheel was 747 pieces. When the diaphragm wheel was used for grinding and polishing of steel pipes, the cloth base strength was insufficient. The sandpaper broke and flying pieces occurred after 282 minutes of use. The number of broken and flying pieces of the diaphragm wheel after grinding was detected to be 20 pieces, accounting for 2.7%. The remaining sandpaper length was 38.5mm, and the sandpaper utilization rate was 38.4%. The wear resistance of the sandpaper was 12.24.

[0130] Comparative Example 3

[0131] A soft abrasive cloth, wherein the steps of the preparation method and the reagents, equipment and process parameters used in the steps are the same as those in Example 2, except that in step (1), warp yarn and weft yarn with a count of 16 are selected for blending to form a base cloth, the yarn count is 100% polyester, and the warp and weft density of the original cloth is 105*50.

[0132] After experimental observation, the comparative example 3 abrasive cloth did not show obvious clumping and sand shedding phenomenon during the flexible bending preparation process. The comparative example 3 abrasive cloth was made into a diaphragm wheel with an outer diameter of 300mm and an abrasive cloth length of 62.5mm. No obvious sand collapse occurred when the diaphragm wheel was punched. The total number of abrasive cloth assembled in the diaphragm wheel was 1563. When the diaphragm wheel was used for steel pipe grinding and polishing, it was found that the steel pipe grinding effect was not good after 46 minutes of use, and the weld scar appeared blue. The diaphragm wheel was observed to have obvious black abrasive cloth. It was analyzed that the cloth base strength was too high, and it was not consumed synchronously with the abrasive, resulting in the abrasive being consumed while the cloth base was still there, slipping occurred, and grinding could not continue.

[0133] Comparative Example 4

[0134] A soft emery cloth, wherein the steps of the preparation method and the reagents, equipment and process parameters used in the steps are the same as those in Example 2, except that in step (1), warp yarn and weft yarn with a count of 16 are selected for blending to form a base cloth, the yarn count is 100% cotton, and the warp and weft density of the original cloth is 105*50.

[0135] After experimental observation, the sandpaper of comparative example 4 did not show obvious clumping and sand shedding phenomenon during the flexible bending preparation process. The sandpaper of comparative example 4 was made into a thousand-leaf wheel with an outer diameter of 300mm and an sandpaper length of 62.5mm. There was no obvious sand collapse when the thousand-leaf wheel was punching. The total number of sandpaper assembled in the thousand-leaf wheel was 1215 pieces. The thick sandpaper resulted in a small number of pieces. When the thousand-leaf wheel was used for grinding and polishing of steel pipes, the cloth base strength was insufficient. The sandpaper broke and flying pieces occurred after 135min of use. The number of broken and flying pieces of the thousand-leaf wheel after grinding was detected to be 83 pieces, accounting for 6.8%. The remaining sandpaper length was 47.5mm, and the sandpaper utilization rate was 24%. The wear resistance of the sandpaper was 9.375.

[0136] Comparative Example 5

[0137] A soft emery cloth, wherein the steps of the preparation method and the reagents, equipment and process parameters used in the steps are the same as those in comparative example 2, except that in steps (2) and (3), polyvinyl alcohol A is replaced by polyvinyl alcohol D in an equal amount, and the viscosity of polyvinyl alcohol D is 25-31 mPas and the degree of alcoholysis is 98-99 mole %;

[0138] In step (2), the cloth base is completely impregnated with an impregnation emulsion, the impregnation emulsion is 25 wt % polyvinyl alcohol D and 75 wt % water, the impregnation emulsion is pre-boiled for 2 h to dissolve, and the impregnation process needs to be maintained at a high temperature of 80°C;

[0139] In step (3), polyvinyl alcohol D is boiled for 2 hours to dissolve, and then mixed with nitrile latex A to prepare a mixed emulsion, which is then coated on the surface of the cloth base to form a surface treatment layer.

[0140] After experimental observation, the sandpaper of comparative example 5 did not show obvious clumping and sand shedding phenomenon during the flexible bending preparation process. The sandpaper of comparative example 5 was made into a diaphragm wheel with an outer diameter of 300mm and a sandpaper length of 62.5mm. No obvious sand collapse phenomenon occurred when the diaphragm wheel was punched. The total number of sandpaper assembled in the diaphragm wheel was 1454 pieces. When the diaphragm wheel was used for steel pipe grinding and polishing, it was found that the cloth base was soft and not strong enough. This is because the alcoholysis degree of polyvinyl alcohol is too high, resulting in poor water solubility and inability to dissolve well in water, making it impossible for polyvinyl alcohol to penetrate into the original cloth. The sandpaper broke and flying pieces occurred when the use time was 986min. At this time, the number of broken and flying pieces of the diaphragm wheel after grinding was 24 pieces, accounting for 1.7%. The remaining sandpaper length was 25.5mm, and the sandpaper utilization rate was 59.2%; the wear resistance of the sandpaper was 27.76.

[0141] Comparative Example 6

[0142] A soft emery cloth, wherein the steps of the preparation method and the reagents, equipment and process parameters used in the steps are the same as those in comparative example 2, except that in steps (2) and (3), polyvinyl alcohol A is replaced by polyvinyl alcohol E in an equal amount, and the viscosity of polyvinyl alcohol E is 4.6-5.4 mPas and the degree of alcoholysis is 86.5-89 mole%.

[0143] After experimental observation, the sandpaper of comparative example 6 did not show obvious clumping and sand shedding phenomenon during the flexible bending preparation process. The sandpaper of comparative example 6 was made into a diaphragm wheel with an outer diameter of 300mm and an sandpaper length of 62.5mm. There was no obvious sand collapse when the diaphragm wheel was punched. The total number of sandpaper assembled in the diaphragm wheel was 1489 pieces. When the diaphragm wheel was used for grinding and polishing of steel pipes, the sandpaper broke and flying pieces appeared after 574 minutes of use. This is because the viscosity of polyvinyl alcohol is relatively low, which leads to a decrease in the strength of the cloth base. After testing the diaphragm wheel after grinding, the number of broken and flying pieces was 39, accounting for 2.6%. The remaining sandpaper length was 32.5mm, and the sandpaper utilization rate was 48%; the wear resistance of the sandpaper was 19.93.

[0144] Comparative Example 7

[0145] A soft emery cloth, the preparation method of which comprises the following steps:

[0146] (1) selecting warp yarn and weft yarn with a count of 16 to blend into a base fabric, wherein the cotton-polyester ratio of the yarn count is 20 wt% cotton and 80 wt% polyester, and the warp and weft density of the original fabric is 105*50;

[0147] (2) The cloth base is completely impregnated with the impregnation emulsion, and then the adhesive is completely pressed into the cloth base using pressure rollers on both sides, and then baked at 130°C until the moisture content is below 1%. The impregnation emulsion is 25wt% polyvinyl alcohol A and 75wt% water. After drying, the amount of polyvinyl alcohol A is calculated to be 26g / m 2 ;

[0148] (3) Apply adhesive emulsion on the front side of the cloth base to be bonded with the abrasive, and bond the abrasive on the adhesive emulsion by electrostatic sand planting. The sand planting gap is 20 mm, the substrate running speed is 22 m / min, the voltage is 38 KV, the frequency is 6 Hz, and the sand planting amount is 550 g / m 2 , the adhesive latex coating amount is 220g / m 2 The adhesive emulsion includes 93wt% phenolic resin A, 1wt% coupling agent and 6wt% cryolite, and the abrasive is calcined brown corundum with a secondary calcination temperature of 1400°C and a particle size of 70#;

[0149] (4) baking the semi-finished emery cloth, and applying a rubber latex on the surface of the abrasive, wherein the rubber latex is 60 wt % of the mass of the adhesive latex, and the rubber latex includes 65 wt % of phenolic resin A, 2 wt % of a coupling agent, and 33 wt % of cryolite;

[0150] Among them, the viscosity of polyvinyl alcohol A is 20.5-24.5mPas, and the alcoholysis degree is 87-89 mole%; the free formaldehyde of phenolic resin A is 0.19%, and the free phenol is 10%;

[0151] (5) After the emery cloth is baked at 130°C, it is heat-wound into a roll in the reverse direction with the abrasive surface facing outward, and then baked until the resin is completely cured. The bending directions are 45° and 90°, the bending knife diameter is 25 mm, and the bending pressure is 5 bar, thereby obtaining a finished emery cloth.

[0152] Through experimental observation, the sand cloth of comparative example 7 showed obvious clumping and sand shedding phenomenon during the preparation of soft bending, and the surface of the sand cloth showed inconsistent smoothness. Inspection found that the phenolic resin A glue for bonding the abrasive had penetrated to varying degrees into the back of the sand cloth, resulting in insufficient bonding in some places. The sand cloth base was soft but the phenolic resin was hard, resulting in serious sand shedding during soft bending. The sand cloth of comparative example 7 was made into a flap wheel with an outer diameter of 300mm and a length of 62.5mm. The flap wheel had serious sand collapse when punching and could not be used.

[0153] Comparative Example 8

[0154] A soft emery cloth, wherein each step of the preparation method and the reagents, equipment and process parameters used in each step are the same as those in Example 2, except that in step (3), the mixed emulsion comprises 98 wt % of acrylate and 2 wt % of polyvinyl alcohol A.

[0155] Through experimental observation, the sand cloth of comparative example 8 did not show obvious clumping and sand shedding phenomenon during the flexible bending preparation process. The sand cloth of comparative example 8 was made into a diaphragm wheel with an outer diameter of 300mm and an sand cloth length of 62.5mm. No obvious sand collapse phenomenon occurred when the diaphragm wheel was punching. The total number of sand cloth assembled in the diaphragm wheel was 1413 pieces. When the diaphragm wheel was used for steel pipe grinding and polishing, the sand cloth was easy to break due to the brittleness of acrylic resin after curing. The probability of sand cloth breakage and flying pieces within 100 minutes of grinding reached 26wt%.

[0156] Comparative Example 9

[0157] A soft emery cloth, wherein each step of the preparation method and the reagents, equipment and process parameters used in each step are the same as those in Example 2, except that in step (3), the mixed emulsion is polyvinyl alcohol A.

[0158] Through experimental observation, the sand cloth of comparative example 9 showed obvious clumping and sand shedding phenomenon during the preparation of soft bending. Inspection found that the phenolic resin A glue for bonding the abrasive had penetrated to varying degrees into the back of the sand cloth, resulting in insufficient bonding in some places. In addition, the sand cloth base was soft but the phenolic resin was hard, resulting in serious sand shedding during soft bending. The sand cloth of comparative example 9 was made into a flap wheel with an outer diameter of 300mm and a length of 62.5mm. The flap wheel had serious sand collapse when punching and could not be used.

[0159] According to GB 4979-1985 "Sheet-shaped Abrasive Cloth and Sandpaper" standard, the finished abrasive cloths prepared in the above embodiments or comparative examples were tested for warp strength, weft strength and average peel strength of the sand-planted surface. Three samples were provided in each group, and the thickness of the abrasive cloth was counted. The test results are shown in Table 2 below.

[0160] Table 2 - Performance test results of abrasive cloth prepared in examples and comparative examples

[0161]

[0162]

[0163] As shown in Table 2 above, the base material of the emery cloths of Comparative Examples 1 and 2 has a high cotton-polyester ratio, and the yarn count is coarse, and the warp density is low, resulting in insufficient toughness of the original cloth. The warp strength of the emery cloth prepared in Comparative Example 1 is significantly lower than that of Example 2, and the warp strength and weft strength of the emery cloth prepared in Comparative Example 2 are significantly lower than those of Example 2, and the peel strength decreases to a certain extent, resulting in the emery cloth being easily broken during grinding and polishing, and the occurrence of broken pieces and flying pieces affects grinding. The utilization rate of the emery cloth is low, the wear resistance of the emery cloth is low, and the thickness of the emery cloth is large, resulting in a low number of assembled pieces of the produced thousand-leaf wheel and a short service life.

[0164] In Comparative Example 3, the base material of the emery cloth is 100% polyester, and the warp and weft strengths of the prepared emery cloth are higher than those of Example 2. The strength of the base is too high. During the grinding and polishing process, it was found that the steel pipe grinding effect was poor after 46 minutes of use, and the weld scar appeared bluish. The thousand-leaf wheel was observed to have obvious black emery cloth. It was analyzed that the base was not consumed synchronously with the abrasive, and grinding could not continue. In Comparative Example 4, the base material of the emery cloth is 100% cotton, the thickness of the emery cloth is too large, and the number of assembled pieces of the thousand-leaf wheel is low. At the same time, the warp and weft strengths of the prepared emery cloth are low, the base strength is insufficient, and the grinding process is prone to breakage and flying pieces, resulting in reduced utilization and wear resistance of the emery cloth.

[0165] By comparing the solutions of Example 2 and Comparative Examples 5 and 7, it can be seen that the viscosity of the polyvinyl alcohol used in the emery cloth in Example 2 is 20.5-26mPas, and the degree of alcoholysis is 86-89mole%, while the degree of alcoholysis of the polyvinyl alcohol used in the emery cloth in Comparative Example 5 is higher, 98-99mole%. Too high a degree of alcoholysis causes the water solubility of polyvinyl alcohol to deteriorate, and it is impossible to absorb it into the interior of the cloth base, making the cloth base softer and insufficient in strength, resulting in broken pieces and flying pieces during grinding; the viscosity of the polyvinyl alcohol used in the emery cloth in Comparative Example 6 is lower, 4.6-5.4mPas, and the viscosity of the polyvinyl alcohol is lower, which also leads to low strength of the cloth base after impregnation, and the prepared emery cloth is prone to broken pieces and flying pieces during the grinding process.

[0166] The cloth base of the emery cloth in comparative example 7 was not surface treated, resulting in the phenolic resin penetrating into the back of the cloth base. The emery cloth in comparative example 9 was coated with polyvinyl alcohol during surface treatment, and polyvinyl alcohol was difficult to effectively block the penetration of the phenolic resin in the adhesive emulsion into the cloth base, resulting in insufficient bonding ability of the phenolic resin to the abrasive in the emery cloths in comparative examples 7 and 9, and the phenolic resin was hard after curing while the cloth base was soft. The prepared emery cloth had serious agglomeration and sand shedding phenomenon during flexing, and was also prone to sand collapse when made into a thousand-leaf wheel, and could not be used normally. In addition, in comparative example 8, the emery cloth was surface treated with a mixed emulsion of acrylate and polyvinyl alcohol. The acrylic resin was brittle after curing, which easily led to the emery cloth breaking during the grinding process, and could not meet the product performance requirements.

[0167] The specific embodiments described above further describe the purpose, technical solutions and beneficial effects of the present application in detail. It should be understood that the above description is only a specific embodiment of the present application and is not intended to limit the scope of protection of the present application. It is particularly pointed out that for those skilled in the art, any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the scope of protection of the present application.

Claims

1. A soft emery cloth, characterized in that: It comprises a cloth base material, a surface treatment layer, an adhesive layer, an abrasive layer and a rubber layer which are arranged in sequence, wherein the abrasive layer is formed by planting sand on the adhesive layer; The cloth-based substrate comprises a raw cloth and an impregnated substance immersed in and dispersed in the raw cloth; The warp count of the original cloth is 16-20, the weft count is 16-20, the warp density is 105-125, the weft density is 50-60, and the original cloth contains the following components in percentage by weight: 15%-40% cotton and 60%-85% polyester; The impregnated material includes polyvinyl alcohol, the viscosity of the polyvinyl alcohol is 20-26 mPas, and the alcoholysis degree is 86-89 mole %; The surface treatment layer contains nitrile latex.

2. The soft abrasive cloth according to claim 1, characterized in that: The raw material for preparing the surface treatment layer is a mixed emulsion, and the mixed emulsion includes the following components in parts by weight: 90-100 parts of nitrile latex and 2-10 parts of polyvinyl alcohol; And / or, the raw material for preparing the adhesive layer is an adhesive latex, and the adhesive latex includes a phenolic resin; And / or, the raw material for preparing the adhesive layer is adhesive latex, and the adhesive latex comprises the following components in parts by weight: 54-75 parts of phenolic resin, 0-3 parts of coupling agent and 25-46 parts of low melting point compound.

3. The soft abrasive cloth according to claim 2, characterized in that: The adhesive emulsion comprises the following components in parts by weight: 90-96 parts of phenolic resin, 0-2 parts of coupling agent and 4-10 parts of low melting point compound.

4. The soft abrasive cloth according to claim 2 or 3, characterized in that: The low melting point compound in the composite latex and the low melting point compound in the adhesive latex are independently selected from at least one of cryolite, potassium fluoroborate, zinc stearate, calcium stearate, graphite, fluorite and molybdenum disulfide.

5. The soft abrasive cloth according to claim 1, characterized in that: The abrasive material of the abrasive layer is at least one of corundum, zirconium corundum, brown corundum, calcined brown corundum, white corundum, ceramic corundum, silicon carbide, and aluminum oxide. The secondary calcination temperature of the calcined brown corundum is 1200° C.-1600° C. And / or, the abrasive particle size number is 40-400#, and the basic particle size of the abrasive is 20-500 μm.

6. The soft abrasive cloth according to any one of claims 2 or 3, characterized in that: The mass percentage of free formaldehyde in the phenolic resin in the adhesive latex and the composite latex is 0.19%-0.28%, and the mass percentage of free phenol is 8.67%-10%; And / or, the solid content of the nitrile latex is 40-60%.

7. The soft abrasive cloth according to claim 1, characterized in that: In the cloth-based substrate, the content of the impregnated substance in the original cloth is 20-30 g / m 2 , And / or, the surface treatment layer is formed by a mixed emulsion, and the coating amount of the mixed emulsion is 30-50g / m 2 , And / or, the amount of abrasive sand is 200-800g / m 2 The thickness of the adhesive layer is 40%-50% of the height of the abrasive basic particles after sand planting. And / or, the adhesive layer is 50wt%-70wt% of the mass of the adhesive layer.

8. A method for preparing the soft abrasive cloth according to any one of claims 1 to 7, characterized in that: The following steps are involved: (1) The original fabric is impregnated with an impregnation emulsion, and the glue is pressed into the original fabric using a roller, followed by drying to form a fabric-based substrate; the impregnation emulsion comprises 20 wt % to 30 wt % of polyvinyl alcohol and the remainder is water; (2) applying the raw materials for preparing the surface treatment layer to one side of the cloth base material for surface coating treatment, and drying to form the surface treatment layer; (3) coating the raw material for preparing the adhesive layer on the surface of the surface treatment layer, and applying sanding with abrasive on the raw material for preparing the adhesive layer, and drying and curing the raw material to form an adhesive layer and an abrasive layer; (4) coating the raw materials for preparing the size layer on the surface of the abrasive layer, drying and completely curing the abrasive layer to form the size layer; (5) The obtained product is flexibly bent to obtain a finished emery cloth.

9. The method for preparing the soft abrasive cloth according to claim 8, characterized in that: Satisfy at least one of the following a)-f): a) In step (1), the drying temperature is 120-150° C., and the drying is performed until the moisture content is below 2%; b) in step (2), the drying temperature is 135-145° C. and the drying time is 2-3 min; c) In step (3), the sand planting gap during the sand planting process is 20-35 mm, the substrate running speed is 22-25 m / min, the voltage is 38-40 KV, and the frequency is 6-8 Hz; d) in step (3), the drying temperature is 120-150° C. and the drying time is 60-120 min; e)) In step (4), the drying temperature is 120-150° C. and the drying time is 120-240 min; f) In step (5), the bending directions are 45° and 90°, the bending knife diameter is 20-30 mm, and the bending pressure is 4-6 bar.

10. Use of the soft abrasive cloth according to any one of claims 1 to 9 in the preparation of flap wheel products.

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