A viscoelastic gum base for shear-thickening polishing and a preparation method and application thereof

Abstract

The application discloses a viscoelastic glue base for shear expansion polishing and a preparation method and application thereof. Boric acid and glycerol are used as base liquid, and a catalyst, an emulsifier, a dispersing agent, abrasive grains and the like are combined to obtain a viscoelastic glue base for shear expansion polishing. The glue base can uniformly contact the surface of a workpiece to be processed, effectively improves the processing efficiency and polishing effect, and has good applicability and economic value. The application aims to optimize the polishing characteristics of the flexible fixed abrasive tool, improve the shear expansion polishing processing efficiency, and thus realize efficient polishing of hard and brittle materials.

Description

Technical Field

[0001] This invention relates to the field of ultra-precision polishing technology, specifically to a viscoelastic adhesive base for shear expansion polishing, its preparation method, and its application. Background Technology

[0002] Ultra-precision polishing is the final and crucial step in machining. It effectively reduces the surface roughness of materials, removes damaged layers, and produces smooth, low-damage surfaces. Currently, it is mainly used in aerospace, precision molds, integrated circuit manufacturing, and medical devices.

[0003] Currently, common polishing methods for hard and brittle materials mainly include chemical mechanical polishing (CMP), electrochemical polishing (ECP), and magnetorheological polishing (MRP). CMP combines the mechanical grinding action of abrasive particles with the chemical action of oxidants, achieving good polishing results, but its polishing solution introduces chemical contamination. Electrochemical polishing involves treating the material in a specific solution to obtain a bright surface, but it may dissolve the work-hardened layer on the workpiece surface, reducing surface hardness. Magnetorheological polishing utilizes a magnetorheological polishing solution in a magnetic field for polishing, achieving high removal rates and avoiding subsurface damage, but its polishing solution is too expensive, and flexible control of the polishing process is difficult to achieve.

[0004] To overcome the problems of the above polishing methods, a Chinese invention patent has been published, patent number: 202010169135.6, patent title: "A High-Efficiency Ultra-Precision Polishing Method Based on Shear Expansion Effect." This is a novel ultra-precision polishing method based on the shear expansion effect of non-Newtonian fluids. It uses a viscoelastic material as the polishing carrier, and prepares a flexible fixed abrasive by mixing abrasive particles and fillers. Polishing is achieved by holding the flexible fixed abrasive with a polishing disc. This method can effectively remove workpiece material and achieve a polishing effect. Currently, there are few domestic processes for preparing viscoelastic adhesive bases for shear expansion polishing, and polyurethane is the preferred raw material for viscoelastic adhesive bases. However, polyurethane has insufficient heat resistance, and its physical properties decrease significantly with increasing temperature, thus limiting its applicability.

[0005] Therefore, this invention utilizes the esterification reaction of boric acid and glycerol to generate borate glycerol polyester, and adds a certain proportion of emulsifier, dispersant, and abrasive particles to prepare a viscoelastic base with non-Newtonian fluid properties. This overcomes the shortcomings of polyurethane, such as insufficient heat resistance and unstable physical properties, thus improving the service life of polishing pads while exhibiting good rheological properties. The shear expansion high-efficiency polishing pad prepared using this viscoelastic base has good applicability and economic value. Summary of the Invention

[0006] To address the issues with the types of adhesive bases used in existing shear expansion polishing, this invention proposes a viscoelastic adhesive base for shear expansion polishing, its preparation method, and its application. The aim is to optimize the polishing characteristics of flexible fixed abrasives, improve the processing efficiency of shear expansion polishing, and thus achieve efficient polishing of hard and brittle materials.

[0007] The technical solution adopted by this invention to solve its technical problem is:

[0008] A viscoelastic adhesive base for shear expansion polishing, comprising a solvent and a solute;

[0009] The solvent is deionized water;

[0010] Based on a total solute mass fraction of 100%, the components and their mass percentage content are as follows: 15-25 wt.% base liquid, 0.6-3.5 wt.% catalyst, 0.1-5.0 wt.% emulsifier, 0.1-2.5 wt.% dispersant, and 1.0-20.0 wt.% abrasive particles.

[0011] Furthermore, the base liquid is boric acid and glycerol. Boric acid and glycerol are added to the catalyst at 70-90°C and stirred for 1-2 hours to generate borate glycerol polyester through esterification reaction.

[0012] Furthermore, the catalyst is p-toluenesulfonic acid, which can improve the formation efficiency of glycerol borate polyester.

[0013] Furthermore, the emulsifier is dimethyl silicone oil and hydroxyl silicone oil.

[0014] Furthermore, the dispersant is sodium hexametaphosphate, which can effectively enhance the dispersibility of the colloidal base.

[0015] Furthermore, the abrasive particles are one or a mixture of at least two of the following: aluminum oxide, silicon oxide, diamond, cerium oxide, magnesium oxide, cubic boron nitride, and silicon carbide.

[0016] A method for preparing a viscoelastic adhesive base for shear expansion polishing includes the following steps:

[0017] First, weigh 15-25 wt.% boric acid and glycerol, add 0.6-3.5 wt.% catalyst, and stir evenly at 70-90℃ for 1-2 hours to generate borate glycerol polyester;

[0018] Subsequently, 0.1–5.0 wt.% emulsifier, 0.1–2.5 wt.% dispersant and 1.0–20.0 wt.% abrasive particles are added sequentially, heated to 150–170°C, and stirred uniformly for 0.5–1 h at a speed of 500–700 r / min to finally obtain a viscoelastic rubber base.

[0019] An application of a viscoelastic adhesive base for shear expansion polishing, wherein the viscoelastic adhesive base is used to prepare a high-efficiency shear expansion polishing disc.

[0020] The beneficial effects of this invention are as follows:

[0021] 1) The base liquid of this invention undergoes an esterification reaction at a specific temperature to generate glycerol borate polyester. It is a flexible material that can make uniform contact with the workpiece, achieving a better polishing effect.

[0022] 2) The addition of abrasive particles during the preparation of the viscoelastic adhesive base of the present invention can enhance the polishing performance of the adhesive base and improve the material removal rate. At the same time, since the viscoelastic adhesive base belongs to the category of flexible fixed abrasives, the contact area between the abrasive particles and the workpiece can be increased during the polishing process, thereby improving the uniformity of force on the workpiece surface and reducing local damage to the workpiece surface.

[0023] 3) The polishing disc prepared by the viscoelastic rubber base described in this invention can achieve better polishing effect in the shear expansion polishing experiment.

[0024] 4) The adhesive base prepared by this invention has low cost, simple preparation process, and will not cause pollution to the environment. Attached Figure Description

[0025] Figure 1 This is a flowchart of the preparation process for viscoelastic adhesive bases.

[0026] Figure 2 The surface morphology of the workpiece before polishing;

[0027] Figure 3 This shows the surface morphology of the workpiece after polishing. Detailed Implementation

[0028] The specific implementation steps of the present invention will be further described below.

[0029] The prepared adhesive base was made into a polishing disc and put into a shear expansion polishing experiment.

[0030] The surface roughness of the workpiece before and after the experiment was measured using a three-dimensional profile white light interferometer, and the surface morphology was observed as follows: Figure 2 and Figure 3 As shown.

[0031] In the adhesive base of this invention, the solvent is deionized water. Based on 100% of the total solute mass, the specific components and their proportions are as follows: base liquid accounts for 15-25 wt.% of the solute mass fraction, catalyst accounts for 0.6-3.5 wt.% of the solute mass fraction, emulsifier accounts for 0.1-5.0 wt.% of the solute mass fraction, dispersant accounts for 0.1-2.5 wt.% of the solute mass fraction, and abrasive particles account for 1.0-20.0 wt.% of the solute mass fraction.

[0032] The specific preparation method follows the formulation given in Table 1. All components are dissolved and uniformly mixed. The base liquid (boric acid and glycerol in a 1:2 ratio) is 20 wt.%, the abrasive particles are 2 wt.% 5 μm diamond, and the emulsifier (dimethyl silicone oil and hydroxyl silicone oil in a 1:2 ratio) is 2.5 wt.%. Deionized water is used to bring the mass percentage to 100 wt. Other experimental conditions are uniform, resulting in 18 sets of examples and 3 control groups. Control group 3 uses a traditional polyurethane polishing pad under the same conditions. All components used in this invention are commercially available.

[0033] Table 1 shows the viscoelastic adhesive composition of the 18 sample groups and the 3 control groups.

[0034]

[0035] To verify the effectiveness of the viscoelastic base described in this invention, polishing discs were prepared using all examples and a control group for experiments. Specific preparation conditions were as follows: The apparatus was a DF-101S thermally charged magnetic stirrer. The base solution was uniformly stirred at 80°C for 1.5 hours to induce an esterification reaction, producing glycerol borate polyester (a catalyst was added depending on the formulation requirements). Subsequently, emulsifier, dispersant, and abrasive particles were added sequentially in a specific ratio. All substances were heated to 160°C in deionized water and uniformly stirred for 0.5 hours. After cooling to room temperature, a viscoelastic base was obtained. The rotation speed was kept constant at 600 r / min.

[0036] The obtained viscoelastic rubber base was prepared into a polishing disc and put into a shear expansion polishing experiment. The specific experimental equipment was the Shenyang Kejing UNIPOL-1200S automatic pressure grinding and polishing machine. The upper disc rotation speed was set to 30 r / min, the lower disc rotation speed was set to 180 r / min, and the polishing time was 10 min. The material removal rate was calculated. The surface morphology after polishing was observed and the surface roughness was detected.

[0037] Table 2 shows the polishing rate and surface roughness after polishing for the first 6 examples in Table 1 and control group 2.

[0038] Example Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Control group 2 Polishing rate (μm / h) 5.49 7.53 8.35 8.67 8.98 8.79 5.21 Surface roughness after polishing (nm) 7.96 4.37 2.98 2.72 2.59 2.67 7.58

[0039] Combining Tables 1 and 2, it can be concluded that the addition of toluenesulfonic acid improves the formation efficiency of glycerol borate polyester compared to the first six examples and the first control group, resulting in better polishing performance. With increasing catalyst dosage, both the material removal rate and surface roughness of the workpiece are optimized; however, the polishing effect begins to decline when the concentration exceeds 2.6 wt.%. Therefore, the optimal catalyst concentration is between 2.6 and 3.5 wt.%.

[0040] Table 3 shows the polishing rate and surface roughness after polishing for examples 7-12 in Table 1 and control group 2.

[0041]

[0042]

[0043] Combining Tables 1 and 3, it can be concluded that the addition of sodium hexametaphosphate enhances the dispersion effect of glycerol borate polyester in the adhesive matrix, resulting in a more uniform distribution of glycerol borate polyester in the adhesive matrix and achieving a better polishing effect, compared with the control group 2 in examples 7-12 and the surface roughness after polishing. As the amount of dispersant increases, the material removal rate of the workpiece increases accordingly, but the surface roughness of the workpiece begins to decrease after the concentration exceeds 0.6 wt.%. Therefore, the optimal concentration of dispersant is between 0.6 and 1.5 wt.%.

[0044] Table 4 shows the polishing rate and surface roughness after polishing for examples 13-18 in Table 1 and control group 1.

[0045] Example Example 13 Example 14 Example 15 Example 16 Example 17 Example 18 Control group 1 Control group 3 Polishing rate (μm / h) 9.71 17.18 21.78 26.46 28.08 34.95 8.98 17.50 Surface roughness after polishing (nm) 2.35 2.11 2.10 1.87 3.33 4.14 2.59 17.63

[0046] Combining Tables 1 and 4, it can be concluded that the polishing rate and surface roughness after polishing of Examples 13 to 18 and Control Group 1 are optimal when the catalyst concentration is 2.6 wt.% and the dispersant concentration is 1.5 to 2.0 wt.%.

[0047] Based on the polishing rate and surface roughness after polishing of the 16th group of examples and the control group 3 in Table 4, it can be concluded that the polishing rate of the polyurethane polishing pad is moderate, but the surface roughness after polishing is not as good as that of the polishing pad prepared with the adhesive base described in this invention.

[0048] In summary, this invention uses boric acid and glycerol as base liquids, combined with catalysts, emulsifiers, dispersants, and abrasives, to obtain a viscoelastic adhesive base for shear expansion polishing. The adhesive base of this invention can make uniform contact with the surface of the workpiece being processed, effectively improving processing efficiency and polishing effect, and possesses good applicability and economic value.

[0049] It should be understood that all wt.% mentioned in this invention refers to mass percentage content.

[0050] It should be noted that the embodiments of the present invention are only for the purpose of facilitating the understanding of the technical solutions of the present invention and do not constitute any limitation. Any simple modifications, equivalent changes and alterations made to the above solutions that depart from the content of the technical solutions of the present invention or are based on the technical essence of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A method for preparing a viscoelastic gum base for shear dilation polishing, characterized by, The viscoelastic base comprises a solvent and a solute, wherein the solvent is deionized water, and the solute, based on a total mass fraction of 100%, comprises the following components and their mass percentage contents as follows: 15.0~25.0 wt.% base liquid, 2.6~3.5 wt.% catalyst, 0.1~5.0 wt.% emulsifier, 0.6~1.5 wt.% dispersant, and 1.0~20.0 wt.% abrasive particles; The base liquid is boric acid and glycerol. Boric acid and glycerol are added to the catalyst at 70~90℃ and stirred for 1~2h to generate borate glycerol polyester through esterification reaction. The catalyst is p-toluenesulfonic acid, which can improve the formation efficiency of glycerol borate polyester. The emulsifier is dimethyl silicone oil and hydroxyl silicone oil; The preparation includes the following steps: First, weigh 15-25 wt.% boric acid and glycerol, add 0.6-3.5 wt.% catalyst, and stir evenly at 70-90℃ for 1-2 hours to generate borate glycerol polyester; Subsequently, 0.1~5.0 wt.% emulsifier, 0.1~2.5 wt.% dispersant and 1.0~20.0 wt.% abrasive are added sequentially, heated to 150~170℃, and stirred evenly for 0.5~1h at a speed of 500~700 r / min to finally obtain viscoelastic rubber base.

2. A method for preparing a viscoelastic gum base for shear dilation polishing according to claim 1, wherein The dispersant is sodium hexametaphosphate, which can effectively enhance the dispersibility of the colloid.

3. A method for preparing a viscoelastic gum base for shear dilation polishing according to claim 1, wherein The abrasive particles are one or a mixture of at least two of the following: aluminum oxide, silicon oxide, diamond, cerium oxide, magnesium oxide, cubic boron nitride, and silicon carbide.

4. A shear-expanding high-efficiency polishing disc, characterized in that, It is made from a viscoelastic adhesive base prepared by any one of the preparation methods described in claims 1-3.

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