阅读说明：本技术 一种低密度环氧发泡型砂轮及其制备方法 (Low-density epoxy foaming type grinding wheel and preparation method thereof ) 是由 郭泽雄 徐莹 江姿 林侠 于 2021-10-21 设计创作，主要内容包括：本发明公开了一种低密度环氧发泡型砂轮及其制备方法,包括步骤：(1)改性环氧树脂粉末的制备：将液体环氧树脂、环氧树脂粉末和双氰胺粉末在100-120℃条件下混合均匀,冷却后打碎成粉末,制得改性环氧树脂粉末；(2)将改性环氧树脂粉末、磨料、液体润湿剂、微球发泡剂和助剂混合均匀,制得混合物；(3)将混合物装入模具中密封保存,再放入70℃-110℃的烘箱加热一定时间,然后继续升温至150-170℃加热一定时间,发泡得到低密度环氧发泡型砂轮。通过该方法制得的低密度环氧发泡型砂轮气孔率高且泡孔均匀,研磨效果较好,粗糙度较低,切削力强,且制备方法工艺简单、成本低、无有害气体排出。(The invention discloses a low-density epoxy foaming type grinding wheel and a preparation method thereof, wherein the preparation method comprises the following steps: (1) preparation of modified epoxy resin powder: uniformly mixing liquid epoxy resin, epoxy resin powder and dicyandiamide powder at the temperature of 100-120 ℃, cooling and crushing into powder to prepare modified epoxy resin powder; (2) uniformly mixing modified epoxy resin powder, an abrasive, a liquid wetting agent, a microsphere foaming agent and an auxiliary agent to prepare a mixture; (3) and (3) placing the mixture into a mold for sealing and storing, then placing the mold into an oven with the temperature of 70-110 ℃ for heating for a certain time, and then continuing to heat to 150-170 ℃ for heating for a certain time to obtain the low-density epoxy foaming grinding wheel through foaming. The low-density epoxy foaming grinding wheel prepared by the method has the advantages of high porosity, uniform pores, good grinding effect, low roughness, strong cutting force, simple preparation method process, low cost and no discharge of harmful gases.)

1. The preparation method of the low-density epoxy foaming type grinding wheel is characterized by comprising the following steps of:

(1) preparation of modified epoxy resin powder: uniformly mixing liquid epoxy resin, epoxy resin powder and dicyandiamide powder at the temperature of 100-120 ℃, cooling and crushing into powder to prepare modified epoxy resin powder;

(2) uniformly mixing modified epoxy resin powder, an abrasive, a liquid wetting agent, a microsphere foaming agent and an auxiliary agent to prepare a mixture;

(3) and (3) placing the mixture into a mold for sealing and storing, then placing the mold into an oven with the temperature of 70-110 ℃ for heating for a certain time, and then continuing to heat to 150-170 ℃ for heating for a certain time to obtain the low-density epoxy foaming grinding wheel through foaming.

2. The method for manufacturing a low-density epoxy-foam grinding wheel according to claim 1, wherein the liquid epoxy resin is at least one selected from the group consisting of bisphenol a epoxy resins and bisphenol F epoxy resins having a viscosity of 25000cps or less at 25 ℃.

3. The method of manufacturing a low-density epoxy-foam grinding wheel according to claim 1, wherein the epoxy resin powder is at least one selected from the group consisting of bisphenol a epoxy resin and phenol novolac epoxy resin.

4. The method for producing a low-density epoxy foam-type grinding wheel according to claim 1, wherein in the step (1), the respective materials are used in amounts of 3 to 5 parts of liquid epoxy resin, 40 to 45 parts of epoxy resin powder and 1 to 3 parts of dicyandiamide powder, respectively.

5. The method for manufacturing a low-density epoxy foam-type grinding wheel according to claim 1, wherein in the step (2), the amounts of the materials are 30 to 50 parts of modified epoxy resin powder, 60 to 80 parts of abrasive, 3 to 8 parts of liquid wetting agent, 1 to 4 parts of microsphere foaming agent and 0.5 to 3 parts of auxiliary agent, respectively.

6. The method of making a low density epoxy-foam grinding wheel according to claim 1, wherein the abrasive is selected from at least one of green silicon carbide, black silicon carbide, alumina, silica, boron nitride, hollow silica, and hollow alumina.

7. The method of manufacturing a low density epoxy-blown grinding wheel according to claim 1, wherein the liquid wetting agent is at least one selected from the group consisting of alicyclic amines, polyamides, and polyetheramines having a viscosity of 2000cps or less at 25 ℃.

8. The method for making a low density epoxy foam grinding wheel as in claim 1, wherein the shell of the microsphere is acrylic resin in the microsphere foaming agent, and the expansion temperature is 80-140 ℃.

9. The method of making a low density epoxy-foam grinding wheel according to claim 1, wherein the auxiliary agent is at least one selected from the group consisting of epoxy diluents, dextrins, surfactants, organosilane coupling agents, and pigments.

10. A low-density epoxy foam grinding wheel, characterized by being produced by the method for producing a low-density epoxy foam grinding wheel according to any one of claims 1 to 9.

Technical Field

The invention relates to the technical field of foaming type grinding wheels, in particular to a low-density epoxy foaming type grinding wheel and a preparation method thereof.

Background

The low-density grinding wheel commonly used in China is developed by combining phenolic resin with an abrasive material, and is characterized in that pores are densely and uniformly distributed, the grinding wheel has certain elasticity, and the polishing effect is good, but the problems of complex manufacturing process, high cost, poor grinding wheel strength, short service life, harmful gas emission in the production process and the like exist. Still, the epoxy resin that uses hollow microspheres to form the pores is combined with the abrasive to produce the grinding wheel, but in order to realize low density, the volume of the hollow spheres needs to be increased, but the problems of poor dispersion and the risks of scratches and the like are caused.

Therefore, it is necessary to develop a low-density epoxy foam-type grinding wheel and a method for manufacturing the same to solve the above-mentioned drawbacks.

Disclosure of Invention

One of the purposes of the invention is to provide a preparation method of a low-density epoxy foaming grinding wheel, the prepared low-density epoxy foaming grinding wheel has the advantages of high porosity, uniform pores, good grinding effect, low roughness, strong cutting force, simple preparation method process, low cost and no discharge of harmful gas.

The invention also aims to provide a low-density epoxy foaming type grinding wheel which is prepared by adopting the method.

In order to achieve the aim, the invention provides a preparation method of a low-density epoxy foaming type grinding wheel, which comprises the following steps:

(1) preparation of modified epoxy resin powder: uniformly mixing liquid epoxy resin, epoxy resin powder and dicyandiamide powder at the temperature of 100-120 ℃, cooling and crushing into powder to prepare modified epoxy resin powder;

(2) uniformly mixing modified epoxy resin powder, an abrasive, a liquid wetting agent, a microsphere foaming agent and an auxiliary agent to prepare a mixture;

(3) and (3) placing the mixture into a mold for sealing and storing, then placing the mold into an oven with the temperature of 70-110 ℃ for heating for a certain time, and then continuing to heat to 150-170 ℃ for heating for a certain time to obtain the low-density epoxy foaming grinding wheel through foaming.

Compared with the prior art, in the preparation method of the low-density epoxy foaming grinding wheel provided by the invention, the epoxy resin is modified, and the dicyandiamide powder is difficult to dissolve in the liquid epoxy resin, so that the dicyandiamide powder can be uniformly dispersed in the epoxy resin powder in a thermal melting mode at the temperature of 100-120 ℃ to obtain the modified epoxy resin powder. And then, reacting the liquid wetting agent with the liquid epoxy resin at 70-110 ℃, shaping in the early stage to form a semi-cured state to form a network structure, so that the temperature is continuously increased to 150-.

Preferably, the liquid epoxy resin is at least one of bisphenol A epoxy resin and bisphenol F epoxy resin with the viscosity of 25000cps or less at 25 ℃, and the bisphenol F epoxy resin is brittle and can fall off quickly, so the bisphenol A epoxy resin is preferably adopted, and the service life of the prepared foaming grinding wheel is longer.

Preferably, the epoxy resin powder is selected from at least one of bisphenol a epoxy resin and phenol novolac epoxy resin. The curing temperature of the bisphenol A epoxy resin powder is 150-170 ℃.

Preferably, the particle size D50 of the epoxy resin powder is 1-30um, such as the particle size D50 of the epoxy resin powder can be but is not limited to 1um, 5um, 10um, 15um, 20um, 25um, 30 um.

Preferably, in the step (1), the amount of each material is 3-5 parts of liquid epoxy resin, 40-45 parts of epoxy resin powder and 1-3 parts of dicyandiamide powder.

Preferably, in the step (2), the amounts of the materials are 30-50 parts of modified epoxy resin powder, 60-80 parts of abrasive, 3-8 parts of liquid wetting agent, 1-4 parts of microsphere foaming agent and 0.5-3 parts of auxiliary agent.

Preferably, the particle size D50 of dicyandiamide powder is 1-15um, but may be, but is not limited to, 1um, 5um, 10um, 15 um.

Preferably, the abrasive is at least one selected from green silicon carbide, black silicon carbide, alumina, silica, boron nitride, hollow silica, and hollow alumina.

Preferably, the particle size D50 of the abrasive is 1-120um, and can be, but is not limited to, 1um, 10um, 20um, 30um, 40um, 50um, 60um, 70um, 80um, 90um, 100um, 110um, 120 um.

Preferably, the liquid wetting agent is at least one of alicyclic amine, polyamide and polyether amine with the viscosity of less than 2000cps at 25 ℃.

Preferably, the shell of the microsphere in the microsphere foaming agent is acrylic resin, the expansion temperature is 80-140 ℃, and the shell of the microsphere is made of acrylic resin, so that the condition that the ground object is scratched when the foaming type grinding wheel is used can be effectively avoided.

Preferably, the auxiliary agent is at least one selected from epoxy diluent, dextrin, surfactant, organosilane coupling agent and pigment.

Correspondingly, the invention also provides a low-density epoxy foaming type grinding wheel which is prepared by adopting the method.

Detailed Description

The following examples are intended to illustrate the present invention, but not to limit the scope of the claims of the present invention.

Example 1

A preparation method of a low-density epoxy foaming type grinding wheel comprises the following steps:

(1) adding 4 parts of liquid bisphenol A epoxy resin E51 (with the viscosity of 20000cps), 40 parts of bisphenol A epoxy resin powder and 0.8 part of dicyandiamide powder into a double-roll mixing mill, mixing at 110 ℃ for 2h, cooling, beating into powder in a wall breaking machine, and sieving with a 300-mesh sieve to obtain modified epoxy resin powder;

(2) mixing 40 parts of modified epoxy resin powder, 70 parts of silicon carbide, 4 parts of polyether amine wetting agent (with the viscosity of 1500cps), 2 parts of acrylic microsphere foaming agent and 0.8 part of coupling agent on a V-shaped mixer for 2 hours to prepare a mixture;

(3) and (3) putting the mixture into a mold, sealing and storing, then putting the mold into an electrothermal blowing oven, heating for 1h at 70 ℃, continuously heating to 160 ℃ for 3h, and foaming to obtain the low-density epoxy foaming type grinding wheel.

Example 2

A preparation method of a low-density epoxy foaming type grinding wheel comprises the following steps:

(1) adding 3 parts of liquid bisphenol F epoxy resin NPEF-170 (the viscosity is 15000cps), 42 parts of bisphenol A epoxy resin powder and 0.9 part of dicyandiamide powder into a double-roll mixing mill, mixing at 100 ℃ for 2h, cooling, beating into powder in a wall breaking machine, and sieving with a 300-mesh sieve to obtain modified epoxy resin powder;

(2) mixing 42 parts of modified epoxy resin powder, 75 parts of alumina, 4.5 parts of polyamide wetting agent (viscosity 2000cps), 0.8 part of acrylic microsphere foaming agent and 0.8 part of coupling agent on a V-shaped mixer for 2 hours to prepare a mixture;

(3) and (3) putting the mixture into a mold, sealing and storing, then putting the mold into an electrothermal blowing oven, heating for 1h at 90 ℃, continuously heating to 150 ℃ for 3h, and foaming to obtain the low-density epoxy foaming type grinding wheel.

Example 3

A preparation method of a low-density epoxy foaming type grinding wheel comprises the following steps:

(1) adding 3.5 parts of liquid bisphenol A epoxy resin E51 (with the viscosity of 20000cps), 35 parts of bisphenol A epoxy resin powder and 0.7 part of dicyandiamide powder into a double-roll mixing mill, mixing at 120 ℃ for 2h, cooling, beating into powder in a wall breaking machine, and sieving with a 300-mesh sieve to obtain modified epoxy resin powder;

(2) mixing 36 parts of modified epoxy resin powder, 67 parts of silicon carbide, 4 parts of alicyclic amine wetting agent (the viscosity is 1000cps), 2 parts of acrylic microsphere foaming agent and 0.8 part of coupling agent on a V-shaped mixer for 2 hours to prepare a mixture;

(3) and (3) putting the mixture into a mold, sealing and storing, then putting the mold into an electrothermal blowing oven, heating for 1h at 110 ℃, continuously heating to 160 ℃ for 3h, and foaming to obtain the low-density epoxy foaming type grinding wheel.

Comparative example 1

A preparation method of a low-density epoxy foaming type grinding wheel comprises the following steps:

(1) adding 4 parts of liquid bisphenol A epoxy resin E51 (with the viscosity of 20000cps), 40 parts of bisphenol A epoxy resin powder and 0.8 part of dicyandiamide powder into a double-roll mixing mill, mixing at 110 ℃ for 2h, cooling, beating into powder in a wall breaking machine, and sieving with a 300-mesh sieve to obtain modified epoxy resin powder;

(2) mixing 40 parts of modified epoxy resin powder, 70 parts of silicon carbide, 2 parts of acrylic microsphere foaming agent and 0.8 part of coupling agent on a V-shaped mixer for 2 hours to prepare a mixture;

(3) and (3) putting the mixture into a mold, sealing and storing, then putting the mold into an electrothermal blowing oven, heating for 1h at 70 ℃, continuously heating to 160 ℃ for 3h, and foaming to obtain the low-density epoxy foaming type grinding wheel.

Comparative example 2

A preparation method of a low-density epoxy foaming type grinding wheel comprises the following steps:

(1) mixing 4 parts of liquid bisphenol A epoxy resin E51 (with the viscosity of 20000cps), 40 parts of bisphenol A epoxy resin powder, 0.8 part of dicyandiamide powder, 70 parts of silicon carbide, 4 parts of polyetheramine wetting agent (with the viscosity of 1500cps), 2 parts of acrylic microsphere foaming agent and 0.8 part of coupling agent on a V-shaped mixer for 2 hours to prepare a mixture;

(2) and (3) putting the mixture into a mold, sealing and storing, then putting the mold into an electrothermal blowing oven, heating for 1h at 70 ℃, continuously heating to 160 ℃ for 3h, and foaming to obtain the low-density epoxy foaming type grinding wheel.

Comparative example 3

A preparation method of a low-density epoxy foaming type grinding wheel comprises the following steps:

(1) adding 45 parts of bisphenol A epoxy resin powder and 0.8 part of dicyandiamide powder into a double-roll mixing mill, mixing at 110 ℃ for 2 hours, cooling, beating into powder in a wall breaking machine, and screening with a 300-mesh screen to obtain modified epoxy resin powder;

(2) mixing 45 parts of modified epoxy resin powder, 70 parts of silicon carbide, 4 parts of polyether amine wetting agent (with the viscosity of 1500cps), 2 parts of acrylic microsphere foaming agent and 0.8 part of coupling agent on a V-shaped mixer for 2 hours to prepare a mixture;

(3) and (3) putting the mixture into a mold, sealing and storing, then putting the mold into an electrothermal blowing oven, heating for 1h at 70 ℃, continuously heating to 160 ℃ for 3h, and foaming to obtain the low-density epoxy foaming type grinding wheel.

The low-density epoxy foam-type grinding wheels obtained in examples 1 to 3 and comparative examples 1 to 3 were subjected to the following performance tests, and the test results are shown in table 1.

The size of the pore is obtained by adopting a metallographic microscope;

the roughness is measured by a Sanfeng roughness tester;

the density and porosity are calculated from the volume of the finished product.

TABLE 1 test results

Test group	Pore size/um	roughness/Ra/um	Porosity/%	Density/g/cm3
					Example 1	40-60	0.15	58	0.8
Example 2	45-60	0.15	55	0.85
					Example 3	50-65	0.16	57	0.82
Comparative example 1	100-300	0.45	75	0.5
					Comparative example 2	50-500	0.6	70	0.55
Comparative example 3	150-300	0.5	77	0.48

From the test results of examples 1-3 and comparative examples 1-3, it can be seen that the epoxy foaming type grinding wheel prepared by the preparation method of the low-density epoxy foaming type grinding wheel has well-controlled and uniform foam holes, good grinding effect and low roughness.

In the technical solutions of examples 1 to 3, the product obtained by pre-curing and post-curing foaming is well controlled and uniform in the system, and has good grinding effect and low roughness.

In comparative examples 1 and 3, the polyether amine wetting agent is absent in comparative example 1 compared with example 1, liquid epoxy resin bisphenol A is not added in comparative example 3, the two materials are critical materials pre-cured at the early stage in the system, if the two materials are absent, a certain network structure cannot be formed at the early stage in the system, the viscoelasticity of the whole structure is poor, the molecular chain cannot be expanded in time, the expansion of the microsphere foaming agent is started, so that air holes cannot be well controlled, the heat release is large after the direct curing by heating, the air holes are promoted to show a continuously increasing trend, and some larger air holes are formed.

In comparative example 2, no hot melt treatment was performed, and no pretreatment was performed on the epoxy resin powder and the dicyandiamide powder, resulting in occurrence of macro pores, because the epoxy resin powder and the dicyandiamide powder were not well dispersed, resulting in local enrichment, severe reaction temperature was too high, and the microsphere foaming agent was expanded beyond the limit and ruptured to cause macro pores.

Although the present invention has been described with reference to a preferred embodiment, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims.