Heat-resistant phenolic resin binder, grinding wheel and preparation method

Abstract

The invention provides a heat-resistant phenolic resin binder, a grinding wheel and a preparation method. The heat-resistant phenolic resin binder comprises the following raw materials in parts by mass: 40-60 parts of liquid phenolic resin, 40-60 parts of solid phenolic resin, 4-8 parts of a curing agent, 10-15 parts of hydroxyl-terminated liquid nitrile rubber and 3-5 parts of a polyfunctional organosilicon epoxy compound. The liquid phenolic resin is prepared by reacting a formaldehyde solution, a polyfunctional organosilicon epoxy compound and phenol under the action of a base catalyst; the solid phenolic resin is prepared by reacting a formaldehyde solution, ellagic acid and phenol under the action of an acid catalyst; the polyfunctional organosilicone epoxy compound is prepared by carrying out hydrosilylation reaction on hydrogen-containing cyclosiloxane and unsaturated glycidyl ester; the concentration of the formaldehyde solution is 30-37wt%; the mass sum of the liquid phenolic resin and the solid phenolic resin is 100 parts. The binding agent has excellent heat resistance, and the prepared grinding wheel shows excellent toughness and durability.

Description

Technical Field

[0001] The invention belongs to the technical field of phenolic resin binders, and in particular relates to a heat-resistant phenolic resin binder, a grinding wheel and a preparation method thereof. Background Art

[0002] Abrasive tools are composed of abrasive grains, pores, and binders. Binders are an indispensable part of abrasive tools. Their function is to bond abrasive grains into a certain geometric shape and hold the abrasive grains so that they can withstand the grinding force during processing and play a cutting role. Abrasive tool binders mainly include resin, ceramic, and metal types. Resin binders are strong and elastic, not afraid of impact, can work at high speeds, have friction and polishing effects, good self-sharpening, not easy to clog, require less dressing, and have high grinding efficiency. Therefore, they are the most widely used.

[0003] The most commonly used resin binder is a phenolic resin-based binder. Phenolic resin is a type of polymer compound generated by a condensation reaction of phenolic compounds and aldehyde compounds under the action of an acidic or alkaline catalyst. Its production raw materials are easily available, the synthesis process is simple, and the production conditions are easy to control. From the structural aspect, phenolic resin-based binders are divided into two types: thermoplastic and thermosetting phenolic resins. Phenolic resin is used as a binder for abrasive tools in the form of thermoplastic resin powder and thermoplastic / thermosetting resin liquid powder. Phenolic resin-based binders also have good mechanical properties, ablation resistance, flame retardancy and electrical insulation properties. For example, the high-performance flexible cutting resin-bonded grinding wheel and its production process disclosed in patent CN101804604B are characterized in that the raw materials are composed of: abrasives composed of single crystal corundum SA and brown corundum A, phenolic resin powder 2893B, phenolic resin liquid PF2550, semi-hydrated gypsum CaSO 4 1 / 2H 2 O, Fe 2 O 3 , FeS 2 ,BaSO 4 This resin binder uses ordinary thermoplastic / thermosetting resin liquid powder as the main resin and a large amount of nitrile rubber as a toughening agent. The resulting abrasive tool has excellent toughness. However, excessive toughening agent reduces the intermolecular force of phenolic resin, resulting in a decrease in heat resistance. Carbonization is easily caused under the action of grinding heat, causing the abrasive grains to fall off prematurely and increasing the amount of wear.

[0004] In order to improve the heat resistance of phenolic resin binders, researchers in this field have conducted a lot of explorations, such as the heat-resistant phenolic resin disclosed in patent CN102153718B and its application in superhard material resin abrasives. The heat-resistant phenolic resin uses formaldehyde, phenol, and 4,4-biphenol as monomers, and the thermoplastic phenolic resin powder or thermosetting phenolic resin liquid prepared by reaction under the conditions of acidic catalysts or alkaline catalysts can be used for superhard material resin abrasives according to the traditional preparation process. It uses a new 4,4-biphenol monomer to synthesize heat-resistant phenolic resin for use in abrasives, which significantly reduces wear, but the use of 4,4-biphenol monomers will reduce the fluidity of the phenolic resin binder and cause defects in the interface between the binder and the abrasive. Although this defect does not have much effect on other properties, under the action of water and heat, water molecules invade from the defective position, causing a significant decline in cutting performance and a significant shortening of the service life.

[0005] In summary, it is necessary to develop a phenolic resin binder with excellent toughness and heat resistance without compromising other properties. Summary of the invention

[0006] In order to solve the above technical problems, the present invention provides a heat-resistant phenolic resin binder, a grinding wheel and a preparation method. The heat-resistant phenolic resin binder includes a multifunctional silicone epoxy compound prepared by hydrosilylation of hydrogenated cyclosiloxane and unsaturated glycidyl ester, a liquid phenolic resin synthesized from formaldehyde solution, multifunctional silicone epoxy compound and phenol, and a solid phenolic resin synthesized from formaldehyde solution, ellagic acid and phenol. The heat resistance of the binder is improved in a synergistic manner of internally doping the multifunctional silicone epoxy compound and ellagic acid with the phenolic resin and externally doping the multifunctional silicone epoxy compound with the phenolic resin; in addition, the terminal hydroxyl liquid nitrile rubber has the effect of improving the toughness of the binder, and the multifunctional silicone epoxy compound with epoxy polar groups can improve the interface bonding strength between the terminal hydroxyl liquid nitrile rubber and other raw materials while improving the heat resistance of the binder, thereby improving the service life of the grinding wheel.

[0007] To achieve the above object, the present invention adopts the following technical solutions:

[0008] A heat-resistant phenolic resin binder comprises the following raw materials in parts by mass: 40-60 parts of liquid phenolic resin, 40-60 parts of solid phenolic resin, 4-8 parts of curing agent, 10-15 parts of hydroxyl-terminated liquid nitrile rubber, and 3-5 parts of multifunctional organic silicon epoxy compound; the liquid phenolic resin is prepared by reacting formaldehyde solution, multifunctional organic silicon epoxy compound, and phenol in a mass ratio of 1.1-1.3:0.1-0.2:1 under the action of an alkali catalyst; the solid The liquid phenolic resin is prepared by reacting formaldehyde solution, ellagic acid and phenol in a mass ratio of 0.6-0.9:0.1-0.3:1 under the action of an acid catalyst; the multifunctional organic silicon epoxy compound is prepared by a hydrosilylation reaction of hydrogenated cyclosiloxane and unsaturated glycidyl ester in a Si-H, C=C molar ratio of 1:1.1-1.15; the concentration of the formaldehyde solution is 30-37wt%; the total mass of the liquid phenolic resin and the solid phenolic resin is 100 parts.

[0009] The hydrogen-containing cyclosiloxane is selected from one or a combination of two or more of 2,4,6,8-tetramethylcyclotetrasiloxane, tetraethylcyclotetrasiloxane, and 2,4,6-trimethylcyclotrisiloxane; and the unsaturated glycidyl ester is selected from one or a combination of two or more of glycidyl methacrylate and glycidyl acrylate.

[0010] The multifunctional organosilicon epoxy compound is prepared by a method comprising the following steps:

[0011] Unsaturated glycidyl ester and chloroplatinic acid catalyst are added to a reaction kettle, the temperature is raised, and hydrogenated cyclosiloxane is added dropwise. After the addition is completed, the reaction is carried out at a constant temperature. After the reaction is completed, distillation is performed under reduced pressure to obtain a multifunctional organosilicon epoxy compound.

[0012] The temperature is raised to 80-100°C. The hydrogen-containing cyclosiloxane is added for 0.5-1h. The constant temperature reaction time is 10-12h. The chloroplatinic acid catalyst is homemade: chloroplatinic acid is added to isopropanol, stirred evenly, and then treated in an ultrasonic oscillator in a 50-70°C water bath for 20-60min to obtain the catalyst. The mass volume ratio of chloroplatinic acid and isopropanol is 15-20g:1000mL. The amount of the chloroplatinic acid catalyst is 0.01-0.03wt% of the mass of the unsaturated glycidyl ester and the hydrogen-containing cyclosiloxane.

[0013] The liquid phenolic resin is prepared by a method comprising the following steps:

[0014] Phenol and alkali catalyst are added into a reaction kettle and mixed evenly. Formaldehyde solution is added dropwise at the first heating, and the reaction is carried out at a constant temperature. After the reaction is completed, the multifunctional organosilicon epoxy compound is added at the second heating, mixed evenly and reacted at a constant temperature. After the reaction is completed, vacuum dehydration is carried out to obtain liquid phenolic resin.

[0015] The alkaline catalyst is an aqueous solution of an alkali with a concentration of 30-40wt%, and the alkali is selected from one or a combination of two or more of sodium hydroxide, potassium hydroxide, barium hydroxide, and lithium hydroxide. The alkaline catalyst is 1-1.5wt% of phenol. The formaldehyde solution is dripped in 1-1.5h. The first heating is to rise to 60-80°C, and the constant temperature reaction time after the formaldehyde solution is dripped is 0.5-1h. The second heating is to rise to 80-90°C, and the constant temperature reaction time after the second heating is 1-2h. The vacuum dehydration is dehydration for 1-3h under the conditions of vacuum degree 0.01-0.09MPa and 40-60°C.

[0016] The solid phenolic resin is prepared by a method comprising the following steps:

[0017] Phenol, ellagic acid and acid catalyst are added into a reaction kettle and mixed evenly, the temperature is raised and formaldehyde solution is added dropwise at a constant temperature, and the reaction is carried out at a constant temperature after the addition is completed. After the reaction is completed, dehydration is performed at normal pressure, vacuum dehydration is performed, and then granulation and grinding are performed to obtain a solid phenolic resin.

[0018] The acid catalyst is selected from one or a combination of two or more of oxalic acid, p-toluenesulfonic acid, formic acid, and acetic acid. The acid catalyst is 0.5-1.5wt% of the mass of phenol and ellagic acid. The formaldehyde solution is dripped in 1-1.5h. The heating is to rise to 95-105°C, and the constant temperature reaction time is 1-2h. The atmospheric pressure dehydration temperature is 100-150°C, the dehydration time is 6-10h, and the vacuum dehydration is dehydrated for 10-30min at a vacuum degree of 0.01-0.095MPa and 150-180°C. The granulation is extrusion granulation at a temperature of 130-150°C, and the average particle size of the granulation is 0.5-1.5cm. The grinding is grinding to 200-325 meshes.

[0019] The number average molecular weight of the hydroxyl-terminated liquid nitrile rubber is 2000-3000, and the hydroxyl content is 0.4-0.5 mmol / g.

[0020] The curing agent is selected from one or a combination of two or more of hexamethylenetetramine, aniline and melamine.

[0021] A heat-resistant phenolic resin bond grinding wheel comprises the following raw materials in parts by mass: 110-130 parts of the phenolic resin bond for the grinding wheel, 400-450 parts of abrasives, 15-30 parts of polishing powder, and 15-60 parts of fillers.

[0022] The abrasive has an average particle size of 30-60 meshes and is selected from one or a combination of two or more of natural corundum, diamond, garnet, white corundum, silicon carbide, and cubic boron nitride.

[0023] The polishing powder has an average particle size of 200-400 meshes and is selected from one or a combination of two or more of aluminum oxide, cerium oxide, zirconium oxide, calcium carbonate and magnesium carbonate.

[0024] The filler has an average particle size of 5-50 μm and is selected from one or a combination of two or more of cryolite, gypsum powder, aluminum hydroxide, copper powder and titanium dioxide.

[0025] The present invention also provides a method for preparing the phenolic resin bonded grinding wheel, comprising the following steps:

[0026] 1) mixing liquid phenolic resin, hydroxyl liquid nitrile rubber, multifunctional silicone epoxy compound, abrasive, polishing powder and filler uniformly, adding solid phenolic resin and curing agent, mixing uniformly, sieving, and obtaining particles as molding material for molding;

[0027] 2) Assemble the mold, put the base mesh at the bottom, mold the molding material, tamp it, scrape it flat, put the base mesh on the top, press it into shape, demould it, harden it, and cool it to room temperature to get the phenolic resin bond grinding wheel.

[0028] The sieving in step 1) is through a 10-35 mesh sieve.

[0029] Step 2) The pressing temperature is 150-210°C and the pressure is 15-45N / mm 2 , time is 30-90min.

[0030] The hardening procedure is: from room temperature, heating to 80-100°C in 60-100min, 80-100°C / 1-2h; from 80-100°C, heating to 100-110°C in 60-100min, 100-110°C / 1-2h; from 100-110°C, heating to 130-160°C in 60-100min, 130-160°C / 1-2h; from 130-160°C, heating to 180-185°C in 60-100min / 1-3h, opening the furnace door when the temperature drops to 40-60°C, and taking out of the furnace at room temperature.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] The binder of the present invention includes a multifunctional organosilicon epoxy compound prepared by hydrosilylation of hydrogenated cyclosiloxane and unsaturated glycidyl ester, a liquid phenolic resin synthesized from formaldehyde solution, multifunctional organosilicon epoxy compound and phenol, and a solid phenolic resin synthesized from formaldehyde solution, ellagic acid and phenol. The heat resistance of the binder is improved in a synergistic manner by internally doping the multifunctional organosilicon epoxy compound and ellagic acid with the phenolic resin and externally doping the multifunctional organosilicon epoxy compound. In addition, the hydroxyl-terminated liquid nitrile rubber has the effect of improving the toughness of the binder, and the multifunctional organosilicon epoxy compound with epoxy polar groups can improve the interface bonding force between the hydroxyl-terminated liquid nitrile rubber and other raw materials while improving the heat resistance of the binder, thereby improving the service life of the grinding wheel. DETAILED DESCRIPTION

[0033] The present invention will be further described below in conjunction with specific embodiments, but is not limited to the contents of the specification. Unless otherwise specified, the "parts" described in the embodiments of the present invention are all parts by weight. The reagents used are all commercially available reagents in the art.

[0034] The hydroxyl liquid nitrile rubber was purchased from Cardolite Chemicals with a grade of PolybdCN-15Y3-80, a number average molecular weight of 3000, and a hydroxyl content of 0.5 mmol / g.

[0035] The average particle size of 46# brown corundum is 46 mesh, which was purchased from Henan Ant New Materials Co., Ltd.

[0036] The average particle size of SHS-46# silicon carbide is 46 mesh and it was purchased from Zhengzhou Shunhengshun Wear Resistant Materials Co., Ltd.

[0037] The average particle size of cerium oxide was 200 mesh and was purchased from Shanghai Huaming Gaona Rare Earth New Materials Co., Ltd.

[0038] The titanium dioxide was NR950 rutile titanium dioxide with an average particle size of 18 μm, purchased from Xuzhou Titanium Dioxide Chemical Co., Ltd.

[0039] The average particle size of cryolite is 325 mesh and was purchased from Shandong Binli New Materials Co., Ltd.

[0040] Example 1

[0041] S1. Add 1.1 mol of glycidyl methacrylate and chloroplatinic acid catalyst (chloroplatinic acid catalyst is 0.01% of the mass of glycidyl methacrylate and 2,4,6,8-tetramethylcyclotetrasiloxane) to the reactor, increase the temperature, drop 0.25 mol of 2,4,6,8-tetramethylcyclotetrasiloxane, and react for 10 hours at a constant temperature after the addition. After the reaction is completed, vacuum distillation is performed to obtain a multifunctional silicone epoxy compound. (Add 0.02 kg of chloroplatinic acid to 1000 ml of isopropanol, stir evenly, and treat in an ultrasonic oscillator in a 50°C water bath for 20 minutes to obtain a chloroplatinic acid catalyst.)

[0042] S2. Add 100g of phenol and 1.5g of 32wt% sodium hydroxide solution into a reactor and mix well. Heat the temperature to 80°C for the first time and add 130g of 37wt% formaldehyde solution dropwise for 1.5h. Keep the temperature constant for reaction. After the reaction, heat the temperature to 85°C for the second time and add 20g of multifunctional silicone epoxy compound, mix well and react at the constant temperature for 1h. After the reaction, dehydrate at 60°C at a vacuum degree of 0.05MPa for 3h to obtain liquid phenolic resin.

[0043] S3. Add 100g of phenol, 30g of ellagic acid and 1.3g of oxalic acid into a reactor and mix evenly. Heat to 105°C and add 90g of 37wt% formaldehyde solution dropwise at a constant temperature for 1.5h. Then react at a constant temperature for 2h. After the reaction, dehydrate at normal pressure at 100°C for 3h, dehydrate at 150°C for 5.0h, dehydrate at 150°C for 15min under a vacuum degree of 0.09MPa, then extrude and granulate at 150°C, grind to an average particle size of 320 mesh, and obtain a solid phenolic resin.

[0044] S41, 40 parts by mass of liquid phenolic resin, 15 parts by mass of hydroxyl liquid nitrile rubber PolybdCN-15Y3-80, 5 parts by mass of multifunctional silicone epoxy compound, 380 parts by mass of 46# brown corundum, 20 parts by mass of SHS-46# silicon carbide, 15 parts by mass of cerium oxide, 15 parts by mass of NR950 titanium dioxide, and 20 parts by mass of cryolite are mixed evenly, 60 parts by mass of solid phenolic resin and 8 parts by mass of hexamethylenetetramine are added and mixed evenly, and the mixture is passed through a 35-mesh sieve, and the obtained particles are used as a molding material for molding;

[0045] S42, assemble the mold, put the base mesh at the bottom, mold the molding material, tamp it, scrape it flat, put the base mesh at the top, press it into shape, demould it, harden it, and cool it to room temperature to get the phenolic resin bond grinding wheel.

[0046] The pressing temperature is 180℃ and the pressure is 45N / mm 2 , time is 30 minutes.

[0047] The hardening procedure is: from room temperature, heating to 100℃ for 100min, 100℃ / 1.5h; from 100℃ to 110℃ for 60min, 110℃ / 1h; from 110℃ to 160℃ for 100min, 160℃ / 2h; from 160℃ to 185℃ for 60min / 3h. Open the furnace door when the temperature drops to 60℃ and take it out of the furnace at room temperature. Grinding wheel specifications (mm): 400×3.2×32 (grinding wheel outer diameter×thickness×aperture).

[0048] Example 2

[0049] The rest is the same as Example 1, except that in step S1, an equimolar amount of tetraethylcyclotetrasiloxane is used to replace 2,4,6,8-tetramethylcyclotetrasiloxane.

[0050] Example 3

[0051] The rest is the same as Example 1, except that in step S2, the amount of the multifunctional silicone epoxy compound used is 10 g.

[0052] Example 4

[0053] The rest is the same as Example 1, except that in step S3, the amount of ellagic acid used is 10 g.

[0054] Example 5

[0055] The rest is the same as Example 1, except that in step S41, the amount of the multifunctional silicone epoxy compound is 3 parts by mass.

[0056] Example 6

[0057] The rest is the same as Example 1, except that in step S41, the amount of hydroxyl liquid nitrile rubber PolybdCN-15Y3-80 used is 10 parts by mass.

[0058] Example 7

[0059] The rest is the same as Example 1, except that in step S41, the amount of liquid phenolic resin is 60 parts by mass, and the amount of solid phenolic resin is 40 parts by mass.

[0060] Example 8

[0061] S1: Add 1.15mol of glycidyl acrylate and chloroplatinic acid catalyst (chloroplatinic acid catalyst is 0.1% of the mass of the two reactants) to the reactor, raise the temperature, drop 0.25mol of 2,4,6,8-tetramethylcyclotetrasiloxane, and react at a constant temperature for 10h. After the reaction, distill under reduced pressure to obtain a multifunctional organosilicon epoxy compound. (Add 0.02kg of chloroplatinic acid to 1000ml of isopropanol, stir evenly, and treat in an ultrasonic oscillator at 50℃ water bath for 20min to obtain the chloroplatinic acid catalyst.)

[0062] S2: Add 100g of phenol and 1.5g of 32wt% sodium hydroxide solution into a reactor and mix evenly. Heat the temperature to 80℃ for the first time and add 110g of 37wt% formaldehyde solution dropwise for 1.5h. Keep the temperature constant for reaction. After the reaction, heat the temperature to 85℃ for the second time and add 10g of multifunctional silicone epoxy compound. Mix evenly and keep the temperature constant for reaction for 1h. After the reaction, dehydrate at 60℃ under vacuum degree of 0.05MPa for 3h to obtain liquid phenolic resin.

[0063] S3: Add 100g phenol, 10g ellagic acid and 1.1g oxalic acid into a reactor and mix evenly. Heat to 105°C and add 60g 37wt% formaldehyde solution dropwise at a constant temperature for 1.5h. Then, react at a constant temperature for 2h. After the reaction, dehydrate at normal pressure at 150°C for 0.5h, dehydrate at 160°C for 30min under a vacuum degree of 0.09MPa, and grind to an average particle size of 320 mesh to obtain a solid phenolic resin.

[0064] S41: 40 parts by mass of liquid phenolic resin, 15 parts by mass of hydroxyl liquid nitrile rubber PolybdCN-15Y3-80, 5 parts by mass of multifunctional silicone epoxy compound, 380 parts by mass of 46# brown corundum, 20 parts by mass of SHS-46# silicon carbide, 15 parts by mass of cerium oxide, 15 parts by mass of NR950 titanium dioxide, and 20 parts by mass of cryolite are mixed evenly, 60 parts by mass of solid phenolic resin and 8 parts by mass of hexamethylenetetramine are added and mixed evenly, and the mixture is passed through a 35-mesh sieve, and the obtained particles are used as a molding material for molding;

[0065] S42 assembles the mold, puts the base mesh at the bottom, molds, compacts, and flattens the molding material, then puts the base mesh at the top, presses and molds, demolds, hardens, and cools to room temperature to obtain a phenolic resin bonded grinding wheel.

[0066] The pressing temperature is 180℃ and the pressure is 45N / mm 2 , time is 30 minutes.

[0067] The hardening procedure is: from room temperature, heating to 100℃ in 100min, 100℃ / 1.5h; from 100℃ to 110℃ in 60min, 110℃ / 1h; from 110℃ to 160℃ in 100min, 160℃ / 2h; from 160℃ to 185℃ in 60min / 3h, open the furnace door when the temperature drops to 60℃, and take out of the furnace at room temperature.

[0068] Comparative Example 1

[0069] The rest is the same as Example 1, except that in step S3, ellagic acid is not added.

[0070] Comparative Example 2

[0071] The rest is the same as Example 1, except that in step S2, no multifunctional organosilicon epoxy compound is added.

[0072] Comparative Example 3

[0073] The rest is the same as Example 1, except that, in step S41, an equal mass of N,N,N,N,-tetracyclyl-4,4-diaminodiphenylmethane is used to replace the multifunctional silicone epoxy compound.

[0074] The bonding agents / grinding wheels prepared in the above embodiments and comparative examples were subjected to the following performance tests:

[0075] Binder performance

[0076] Heat resistance: thermogravimetric analyzer, temperature range 30-900°C, 5°C / min, nitrogen, record the initial decomposition temperature.

[0077] Grinding wheel performance

[0078] Impact strength: refer to GB / T 1039-92, span 60mm, speed of pendulum impacting the test center is 2.9m / s, and the spline is 120×15×10mm.

[0079] Grinding ratio: Grinding ratio refers to the mass of the workpiece that is removed by the unit mass of the abrasive tool. If the consumption of the abrasive tool is relatively small, and the consumption of the workpiece is large, the grinding is relatively large, and the abrasive tool has good wear resistance. Grinding test of grinding wheel (specification 15mm×20mm×6.5mm) and 45# quenched steel (specification 50mm×25mm×25mm), grinding wheel linear speed v s =30(m / s), axial feed rate f a =0(mm), workpiece speed v w =50(mm / s), radial feed rate f r =0.008(mm), calculate the grinding ratio G:

[0080] G=(g1 -g 2 ) / (w 1 -w 2 )

[0081] Among them, g 1 -Mass of the wear part 45# quenched steel before wear, g;

[0082] g 2 -The mass of the wear part 45# quenched steel after wear, g;

[0083] w 1 -Mass of grinding wheel before wear, g;

[0084] W 2 -Mass of grinding wheel after wear, g;

[0085] Anti-fading performance: Place the abrasive tool in water, boil it for 2 hours, re-measure the grinding ratio, and calculate the grinding ratio loss rate.

[0086] Table 1 Performance test results

[0087]

[0088]

[0089] From the heat resistance test results of Example 1 and Comparative Examples 1-3 in Table 1, it can be seen that the synergistic approach of doping phenolic resin with multifunctional silicone epoxy compounds and ellagic acid and doping phenolic resin with multifunctional silicone epoxy compounds can significantly improve the heat resistance of the binder.

[0090] It can be seen from the impact strength test results in Table 1 that, under the cooperation of the hydroxyl-terminated liquid nitrile rubber, the multifunctional silicone epoxy compound and ellagic acid, the grinding wheel prepared by the present invention has both excellent heat resistance and impact resistance.

[0091] From the grinding ratio loss rates of Example 1, Examples 5-6, and Comparative Examples 1-3 in Table 1, it can be seen that the multifunctional silicone epoxy compound can effectively reduce the grinding ratio loss of the grinding wheel, while the conventional multifunctional epoxy compound has no obvious improvement effect.

[0092] The above detailed description is a specific description of one feasible embodiment of the present invention. The embodiment is not intended to limit the patent scope of the present invention. Any equivalent implementation or modification that does not deviate from the present invention should be included in the scope of the technical solution of the present invention.

Claims

1. A heat-resistant phenolic resin binder, characterized in that: The invention comprises the following raw materials in parts by weight: 40-60 parts of liquid phenolic resin, 40-60 parts of solid phenolic resin, 4-8 parts of curing agent, 10-15 parts of hydroxyl-terminated liquid nitrile rubber, and 3-5 parts of multifunctional organic silicon epoxy compound; the liquid phenolic resin is prepared by reacting formaldehyde solution, multifunctional organic silicon epoxy compound, and phenol in a mass ratio of 1.1-1.3:0.1-0.2:1 under the action of an alkali catalyst; the solid phenolic resin is prepared by reacting The formaldehyde solution, ellagic acid and phenol are reacted in a mass ratio of 0.6-0.9:0.1-0.3:1 under the action of an acid catalyst to prepare the compound; the multifunctional organic silicon epoxy compound is prepared by a hydrosilylation reaction of a hydrogenated cyclosiloxane and an unsaturated glycidyl ester in a Si-H, C=C molar ratio of 1:1.1-1.15; the concentration of the formaldehyde solution is 30-37wt%; the total mass of the liquid phenolic resin and the solid phenolic resin is 100 parts.

2. The heat-resistant phenolic resin binder according to claim 1, characterized in that: The hydrogen-containing cyclosiloxane is selected from one or a combination of two or more of 2,4,6,8-tetramethylcyclotetrasiloxane, tetraethylcyclotetrasiloxane, and 2,4,6-trimethylcyclotrisiloxane; and the unsaturated glycidyl ester is selected from one or a combination of two or more of glycidyl methacrylate and glycidyl acrylate.

3. The heat-resistant phenolic resin binder according to claim 1, characterized in that: The multifunctional organosilicon epoxy compound is prepared by a method comprising the following steps: Unsaturated glycidyl ester and chloroplatinic acid catalyst are added to a reaction kettle, the temperature is raised, and hydrogenated cyclosiloxane is added dropwise. After the addition is completed, the reaction is carried out at a constant temperature. After the reaction is completed, distillation is performed under reduced pressure to obtain a multifunctional organosilicon epoxy compound.

4. The heat-resistant phenolic resin binder according to claim 1, characterized in that: The liquid phenolic resin is prepared by a method comprising the following steps: Phenol and alkali catalyst are added into a reaction kettle and mixed evenly, the formaldehyde solution is added dropwise at a higher temperature, and the reaction is carried out at a constant temperature after the addition is completed. After the reaction is completed, the multifunctional silicone epoxy compound is added at a higher temperature and mixed evenly and the reaction is carried out at a constant temperature. After the reaction is completed, vacuum dehydration is carried out to obtain a liquid phenolic resin.

5. The heat-resistant phenolic resin binder according to claim 1, characterized in that: The solid phenolic resin is prepared by a method comprising the following steps: Phenol, ellagic acid and acid catalyst are added into a reaction kettle and mixed evenly, the temperature is raised and formaldehyde solution is added dropwise at a constant temperature, and the reaction is carried out at a constant temperature after the addition is completed. After the reaction is completed, dehydration is performed at normal pressure, vacuum dehydration is performed, and then granulation and grinding are performed to obtain a solid phenolic resin.

6. The heat-resistant phenolic resin binder according to claim 5, characterized in that: The temperature is raised to 95-105° C., and the constant temperature reaction time is 1-2 hours; the normal pressure dehydration temperature is 100-150° C., and the dehydration time is 6-10 hours; the vacuum dehydration is dehydration at a vacuum degree of 0.01-0.095 MPa and 150-180° C. for 10-30 minutes; and the grinding is grinding to 200-325 meshes.

7. The heat-resistant phenolic resin binder according to claim 1, characterized in that: The number average molecular weight of the hydroxyl-terminated liquid nitrile rubber is 2000-3000, and the hydroxyl content is 0.4-0.5 mmol / g.

8. A heat-resistant phenolic resin bond grinding wheel, characterized in that: The invention comprises the following raw materials in parts by mass: 110-130 parts of the phenolic resin binder for the grinding wheel according to any one of claims 1 to 7, 400-450 parts of abrasives, 15-30 parts of polishing powder, and 15-60 parts of fillers.

9. The heat-resistant phenolic resin bond grinding wheel according to claim 8, characterized in that: The average particle size of the abrasive is 30-60 mesh, and is selected from one or a combination of two or more of natural corundum, diamond, garnet, white corundum, silicon carbide, and cubic boron nitride; the average particle size of the polishing powder is 200-400 mesh, and is selected from one or a combination of two or more of aluminum oxide, cerium oxide, zirconium oxide, calcium carbonate, and magnesium carbonate; the average particle size of the filler is 5-50 μm, and is selected from one or a combination of two or more of cryolite, gypsum powder, aluminum hydroxide, copper powder, and titanium dioxide.

10. The method for preparing the phenolic resin bonded grinding wheel according to claim 8, characterized in that: The steps include: 1) mixing liquid phenolic resin, hydroxyl liquid nitrile rubber, multifunctional silicone epoxy compound, abrasive, polishing powder and filler uniformly, adding solid phenolic resin and curing agent, mixing uniformly, sieving, and obtaining particles as molding material for molding; 2) Assemble the mold, put the base mesh at the bottom, mold the molding material, tamp it, scrape it flat, put the base mesh on the top, press it into shape, demould it, harden it, and cool it to room temperature to get the phenolic resin bond grinding wheel.

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