Accumulated hollow glass bead pore-forming agent as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of consolidation grinding tool preparation, and particularly relates to a stacked hollow glass bead pore-forming agent and a preparation method and application thereof. The stacked hollow glass bead pore-forming agent comprises a wax matrix, wherein a plurality of hollow glass beads are dispersed in the wax matrix; the hollow glass beads account for 70-90% of the total mass of the wax and the hollow glass beads. The hollow glass beads are bonded through wax to form an accumulation body pore-forming agent, the wax is liquefied or gasified after being heated, a large number of hollow glass beads are recovered to be in an easy-to-flow state again, heat generated in the grinding process and abrasive dust are rapidly brought out, the heat dissipation and chip removal capacity is enhanced, and therefore the grinding capacity of the grinding wheel is continuously exerted, and the service life of the grinding wheel is prolonged. And the situation that the grinding performance is reduced due to the fact that heat dissipation is poor and abrasive dust is not discharged in time is avoided.

Description

Technical Field

[0001] The invention belongs to the technical field of bonded abrasive tool preparation, and in particular relates to a stacked hollow glass microbead pore-forming agent and a preparation method and application thereof. Background Art

[0002] The structure of the porous grinding wheel is relatively loose, and the size of its pores is much larger than the abrasive particle size, so it has some special grinding properties, with the characteristics of good grinding heat dissipation and not easy to clog. The structure number of the porous grinding wheel can vary between 10 and 14, and the pore size can be adjusted in the range of 0.25 to 1.5 mm or larger. Generally, the pore size range is required to be between 0.125 mm and 1.180 mm. When grinding difficult-to-grind materials such as stainless steel, titanium alloy, and heat-resistant steel, a single large-allowance cutting process is usually required. A large amount of grinding chips and heat will be generated during the cutting process. At this time, it is easy for grinding chips to adhere to the grinding wheel and the abrasive tool to be clogged, resulting in quality problems such as burns and cracks on the workpiece surface. At this time, porous resin bond abrasive tools are generally used to achieve efficient grinding of the above materials, and to minimize quality defects such as burns and cracks on the workpiece surface after grinding.

[0003] The Chinese invention patent with the authorization announcement date of February 13, 2018 and the authorization announcement number CN105437091B discloses a large-pore resin-bonded superhard material grinding wheel for stainless steel end surface grinding, wherein the grinding wheel abrasive layer is prepared from cubic boron nitride, silicon carbide, high-temperature resistant resin powder, chromium oxide, electrolytic copper powder, graphite, and hollow alumina balls, wherein the hollow alumina balls act as pore-forming agents with a diameter of 2 to 3.5 mm. During the grinding process, the hollow alumina balls are broken and large-sized pores are formed in the matrix. The resin-bonded grinding wheel based on the hollow alumina ball pore-forming agent exhibits good grinding performance and avoids workpiece burns.

[0004] The disadvantages of using hollow alumina balls as pore-forming agents are: (1) the upper limit of porosity is limited. This is because the use of the placeholder method to manufacture porous grinding wheels is subject to the upper limit of the solid matter, resulting in the porosity being unable to be increased indefinitely; (2) the pore distribution is uneven. Due to the high viscosity of the resin liquid, it is more difficult to mix the molding material evenly, resulting in uneven pore distribution of the resin grinding wheel.

[0005] Another commonly used pore-forming agent is refined naphthalene, which is an organic pore-forming agent. Refined naphthalene of appropriate particle size is introduced into the porous resin bond grinding wheel. After being heated, refined naphthalene volatilizes to form pores. The refined naphthalene volatilizes without residue but causes great harm to the environment. At the same time, when used in porous resin bond grinding wheels, the ability of refined naphthalene pore-forming agents to dissipate heat and reduce sticking is still lacking, which also leads to a decrease in the grinding performance of porous resin bond grinding wheels. Summary of the invention

[0006] The first object of the present invention is to provide a stacked hollow glass microsphere pore-forming agent, so as to solve the problem that the application of refined naphthalene pore-forming agent in large-sized resin bonded grinding wheels will cause the grinding performance of the grinding wheels to decrease.

[0007] The second object of the present invention is to provide a method for preparing the above-mentioned stacked hollow glass microsphere pore-forming agent to solve the above-mentioned problems.

[0008] The third object of the present invention is to provide the use of the above-mentioned stacked hollow glass microsphere pore-forming agent in porous resin bonded abrasive tools to solve the problem that the grinding removal ability of porous resin bonded abrasive tools needs to be improved.

[0009] In order to achieve the above first purpose, the technical solution adopted by the present invention is:

[0010] A stacked hollow glass microsphere pore-forming agent comprises a wax matrix in which a plurality of hollow glass microspheres are dispersed; the hollow glass microspheres account for 70-90% of the total mass of the wax and the hollow glass microspheres.

[0011] The present invention is a pioneering invention. Hollow glass microbeads are bonded with wax to form a deposited pore-forming agent. The wax liquefies or vaporizes after being heated, and a large number of hollow glass microbeads resume an easy-to-flow state, quickly taking out the heat generated in the grinding process and the grinding chips, thereby enhancing the heat dissipation and chip removal capabilities, thereby allowing the grinding ability of the grinding wheel to continue to be exerted, avoiding the degradation of grinding performance due to poor heat dissipation and untimely discharge of grinding chips.

[0012] Preferably, the wax matrix is ​​selected from palm wax or composite wax, the composite wax is composed of one or two of paraffin wax and beeswax and palm wax, and the mass proportion of palm wax in the composite wax is more than 85%. The specific wax type can be selected from the specific gravity, melting point and cost of the wax. Palm wax has the best effect, but the cost is slightly higher. Appropriate addition of paraffin wax, beeswax, etc. can reduce the cost on the basis of basically maintaining the grinding performance.

[0013] Further preferably, the composite wax is composed of the following components in mass fractions: 5-10% paraffin, 1-5% beeswax, and the rest is palm wax.

[0014] Preferably, the melting point of the palm wax is 82-85° C., the melting point of the paraffin wax is 30-35° C., and the melting point of the beeswax is 62-67° C. If the melting point of the wax matrix is ​​too high, it is not easy to volatilize and gasify during grinding, and it is easy to adhere to the surface of the workpiece, affecting the surface quality of the workpiece; if the melting point is too low, the pore-forming agent is not easy to store in the high room temperature in summer, and it is easy to deform and adhere, affecting the pore-forming performance.

[0015] Preferably, the hollow glass microspheres have a particle size of 10 to 250 μm and a wall thickness of 1 to 2 μm.

[0016] Preferably, the pore-forming agent is a granule with a particle size of 0.125 mm to 1.180 mm. The granule with a particle size of 0.125 mm to 1.180 mm can form pores of corresponding size in the matrix, thereby meeting the grinding needs of porous resin-bonded abrasive grinding wheels.

[0017] In order to achieve the above second purpose, the technical solution adopted by the present invention is:

[0018] The preparation method of the above-mentioned stacked hollow glass microsphere pore-forming agent comprises the following steps: mixing the hollow glass microspheres and wax melt, cooling and solidifying, and then crushing and classifying to obtain a pore-forming agent that meets the particle size requirements.

[0019] The preparation method of the stacked hollow glass microsphere pore-forming agent of the present invention utilizes a wax melt mixing method to mix the hollow glass microspheres and wax, and then crushes and screens the particles into the required particle size after cooling and solidification. The process is simple and the obtained product has good stability.

[0020] Preferably, the wax melt is prepared by melting a wax block at 120-150° C. and keeping the temperature for 10-30 minutes.

[0021] In order to achieve the third purpose above, the technical solution adopted by the present invention is:

[0022] The application of the above-mentioned stacked hollow glass microsphere pore-forming agent in porous resin bonded abrasive tools.

[0023] The stacked hollow glass microsphere pore-forming agent can be added to the porous resin bond abrasive tool in a conventional manner. It can not only introduce large-sized pores, but also utilize a large number of hollow glass microspheres to significantly improve heat dissipation and chip removal, thereby improving the grinding performance of the porous resin bond abrasive tool and effectively extending the grinding life of the porous resin bond abrasive tool. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the cross-sectional structure of the stacked hollow glass microsphere pore-forming agent of the present invention;

[0025] Figure 2 It is a schematic diagram of the stacked hollow glass microsphere pore-forming agent used in the porous resin bonded abrasive tool of the present invention;

[0026] Among them, 1-wax matrix; 2-hollow glass microspheres; 3-grinding wheel body; 4-resin binder; 5-abrasive; 6-stacked hollow glass microsphere pore-forming agent. DETAILED DESCRIPTION

[0027] The technical concept of the present invention is to use wax and hollow glass microspheres to make an accumulation body mainly composed of hollow glass microspheres. The accumulation body uses the wax to liquefy or vaporize when heated to leave the matrix. The wax plays a temporary bonding and lubricating role. After the wax is liquefied or vaporized, a large number of hollow glass microspheres in the wax are in a free-flowing state, quickly taking away heat and grinding chips, so that the sharpness of the resin bond grinding wheel is not affected by chip adhesion and heat dissipation, thereby avoiding a decrease in grinding performance and grinding life.

[0028] Wax is often used to make candles, lubricants, waterproofing agents, etc. Different waxes have different melting points and their performances are also very different. When choosing wax, if the melting point of the wax is too low, such as soybean wax with a melting point of 45-60°C, the problem is that it is not easy to store, especially in summer when the room temperature exceeds 45°C, the pore-forming agent is prone to softening, deformation, adhesion, etc., which affects the performance of the pore-forming agent. If the melting point of the wax is too high, such as polyethylene wax with a melting point of 95-115°C, it is not easy to volatilize and gasify. During the grinding process, it will adhere to the surface of the workpiece, which will affect the grinding quality of the workpiece surface.

[0029] Considering the pore-forming agent performance, cost and grinding performance, palm wax is a plant wax that is easily degraded and more environmentally friendly; paraffin is a mineral wax with a low melting point and is relatively cheap from a cost perspective; and beeswax is an animal wax with a low density (palm wax 0.990-0.999g / cm 3 、Paraffin 0.850-0.950g / cm 3 , beeswax 0.954-0.964g / cm 3 ), soft and brittle texture, etc. The melting point, density, etc. of the pore-forming agent can be adjusted according to the properties and addition ratio of different waxes.

[0030] By further optimizing the wax species, the melting point, specific gravity and cost of the wax matrix can be taken into consideration, and the dispersion of the pore-forming agent in the preparation of the resin bond grinding wheel (minimizing floating), the stability of the deposited body coating structure, the production cost, etc. can be further improved, so that the grinding characteristics of the porous resin bond grinding wheel can be fully utilized.

[0031] The implementation process of the present invention is described in detail below in conjunction with specific examples. The raw materials used in the following examples are all commercially available conventional raw materials, and the specifications of the main raw materials are listed in Table 1.

[0032] Table 1 Specifications of main raw materials

[0033]

[0034]

[0035] 1. Specific embodiments of the stacked hollow glass microsphere pore-forming agent and its preparation method of the present invention

[0036] Example 1

[0037] The stacked hollow glass microsphere pore-forming agent of this embodiment has a structural schematic diagram as shown in FIG. Figure 1 As shown, it includes a wax matrix 1, in which a plurality of hollow glass microspheres 2 are dispersed; the hollow glass microspheres 2 account for 87% of the total mass of the wax and the hollow glass microspheres.

[0038] The preparation method of the stacked hollow glass microsphere pore-forming agent of this embodiment comprises the following steps:

[0039] Take 1000g palm wax, heat it at 120℃ in a stainless steel container until it is completely melted, then keep it warm for 30min, add 6700g hollow glass microspheres in the heat preservation state, stir it evenly, and cool it in the container at room temperature. After it is completely solidified into blocks, use a hammer to break it into blocks, crush it in a roller crusher, and screen it to get the piled hollow glass microsphere pore-forming agent. It is generally divided into three grades for use, that is, the pore size range is large pores (0.410~1.180mm), medium pores (0.180~0.325mm), and micro pores (0.125~0.150mm). Coarse particles that do not meet the requirements can continue to be crushed and granulated until they meet the requirements. Fine particles that do not meet the requirements can continue to be melted for secondary recycling.

[0040] The density of the stacked hollow glass microsphere pore-forming agent obtained in this example is 0.750 g / cm 3 .

[0041] Example 2

[0042] The stacked hollow glass microsphere pore-forming agent of this embodiment has the same structure as that of embodiment 1, and comprises a wax matrix in which a plurality of hollow glass microspheres are dispersed; the hollow glass microspheres account for 89% of the total mass of the wax and the hollow glass microspheres.

[0043] The preparation method of the stacked hollow glass microsphere pore-forming agent of this embodiment comprises the following steps:

[0044] Take 850g palm wax, 100g paraffin wax and 50g beeswax, heat them at 130℃ in a stainless steel container until they are all melted, then keep them warm for 20min, add 8000g hollow glass microspheres in the heat preservation state, stir them thoroughly and cool them in the container at room temperature. When they are all solidified into blocks, use a hammer to break them into blocks, crush them in a roller crusher, and screen them to obtain the stacked hollow glass microsphere pore-forming agent.

[0045] The density of the stacked hollow glass microsphere pore-forming agent obtained in this example is 0.720 g / cm 3 .

[0046] Example 3

[0047] The stacked hollow glass microsphere pore-forming agent of this embodiment has the same structure as that of embodiment 1, and comprises a wax matrix in which a plurality of hollow glass microspheres are dispersed; the hollow glass microspheres account for 90% of the total mass of the wax and the hollow glass microspheres.

[0048] The preparation method of the stacked hollow glass microsphere pore-forming agent of this embodiment comprises the following steps:

[0049] Take 850g palm wax, 100g paraffin wax, and 50g beeswax, heat them at 150℃ in a stainless steel container until they are all melted, then keep them warm for 10min, add 9000g hollow glass microspheres in the heat preservation state, stir them completely and cool them at room temperature in the container. When they are all solidified into blocks, use a hammer to break them into blocks, crush them in a roller crusher, and screen them to obtain the stacked hollow glass microsphere pore-forming agent.

[0050] The density of the stacked hollow glass microsphere pore-forming agent obtained in this example is 0.700 g / cm 3 .

[0051] Example 4

[0052] The stacked hollow glass microsphere pore-forming agent of this embodiment has the same structure as that of embodiment 1, and comprises a wax matrix in which a plurality of hollow glass microspheres are dispersed; the hollow glass microspheres account for 70% of the total mass of the wax and the hollow glass microspheres.

[0053] The preparation method of the stacked hollow glass microsphere pore-forming agent of this embodiment comprises the following steps:

[0054] Take 950g palm wax and 50g beeswax, heat them at 140℃ in a stainless steel container until they are completely melted, then keep them warm for 30min, add 2350g hollow glass microspheres in the heat preservation state, stir them completely and cool them in the container at room temperature. When they are all solidified into blocks, use a hammer to break them into blocks, crush them in a roller crusher, and screen them to obtain the stacked hollow glass microsphere pore-forming agent.

[0055] The density of the stacked hollow glass microsphere pore-forming agent obtained in this example is 0.850 g / cm 3 .

[0056] 2. Application examples of stacked hollow glass microsphere pore formers in porous resin bonded abrasive tools

[0057] Example 5

[0058] Under the same process parameters, the stacked hollow glass microsphere pore-forming agent of each embodiment and the refined naphthalene pore-forming agent (comparative example, medium pore, 0.180-0.325 mm) were made into a multi-porous grinding wheel product with consistent specifications. Figure 2As shown, the grinding wheel body 3 includes a resin binder 4, abrasives 5 distributed in the resin binder 4, and a stacked hollow glass microbead pore-forming agent 6.

[0059] Grinding wheel products are manufactured according to conventional multi-porous grinding wheel product formula and process. Specifically, the molding material is composed of the following components by mass fraction: brown corundum abrasive AF120, 41.75%; white corundum abrasive WAF120, 41.75%; phenolic resin powder 13%; phenolic resin liquid 3.5%. 60 grams of pore-forming agent is added to each kilogram of molding material. The feed density is 2.04g / cm 3 The molding pressure is 22.5 MPa. The grinding wheel product is manufactured according to the steps of batching, mixing, molding, curing (180° C.), and processing. The multi-porous grinding wheels based on the pore-forming agents of the embodiments and comparative examples are consistent with each other except for the different types of pore-forming agents.

[0060] A comparative grinding experiment was conducted on the multi-porous grinding wheels based on the pore-forming agents of different embodiments and the refined naphthalene pore-forming agent. The end face of the bearing ring made of bearing steel was ground with the specifications of diameter Φ500×thickness 55×aperture Φ20, grinding pressure of 5.63Kg, working linear speed of 35m / s, grinding feed amount of 0.005mm each time, and the grinding results are shown in Table 2.

[0061] Table 2 Comparison of grinding results

[0062] serial number Durability, piece / revision 1 time Service life, pieces / pieces Workpiece surface quality Example 1 35 1530 No burns, no chatter marks Example 2 36 1550 No burns, no chatter marks Example 3 40 1600 No burns, no chatter marks Example 4 35 1500 No burns, no chatter marks Comparative Example 30 1480 Some have slight burns and no vibration marks

[0063] It can be seen from Table 2 that the grinding quality and efficiency of the porous grinding wheel based on the stacked hollow glass microbead pore-forming agent of the embodiment are significantly higher than those of the porous grinding wheel based on the refined naphthalene pore-forming agent, showing excellent wear resistance and long service life, and the surface quality of the workpiece is also improved.

Claims

1. A stacked hollow glass microsphere pore-forming agent, characterized in that: The invention comprises a wax matrix in which a plurality of hollow glass microspheres are dispersed; the hollow glass microspheres account for 70-90% of the total mass of the wax and the hollow glass microspheres.

2. The stacked hollow glass microsphere pore-forming agent according to claim 1, characterized in that: The wax matrix is ​​selected from palm wax or composite wax, the composite wax is composed of palm wax and one or two of paraffin wax and beeswax, and the mass proportion of the palm wax in the composite wax is more than 85%.

3. The stacked hollow glass microsphere pore-forming agent according to claim 2, characterized in that: The composite wax is composed of the following components in mass fractions: 5-10% paraffin, 1-5% beeswax, and the rest is palm wax.

4. The stacked hollow glass microsphere pore-forming agent according to claim 2, characterized in that: The melting point of the palm wax is 82-85°C, the melting point of the paraffin wax is 30-35°C, and the melting point of the beeswax is 62-67°C.

5. The stacked hollow glass microsphere pore-forming agent according to claim 1, characterized in that: The hollow glass microspheres have a particle size of 10 to 250 μm and a wall thickness of 1 to 2 μm.

6. The stacked hollow glass microsphere pore-forming agent according to claim 1, characterized in that: The pore-forming agent is a granule with a particle size of 0.125 mm to 1.180 mm.

7. A method for preparing a stacked hollow glass microsphere pore-forming agent as claimed in any one of claims 1 to 6, characterized in that: The method comprises the following steps: mixing hollow glass microspheres and wax melt, cooling and solidifying, and then crushing and classifying to obtain a pore-forming agent meeting the particle size requirements.

8. The method for preparing the stacked hollow glass microsphere pore-forming agent according to claim 7, characterized in that: The wax melt is prepared by melting a wax block at 120-150° C. and keeping the temperature for 10-30 minutes.

9. Use of the stacked hollow glass microsphere pore former as claimed in any one of claims 1 to 6 in a porous resin bonded abrasive tool.

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