A micro-replicated structure coated abrasive tool and its preparation method

Abstract

The present invention discloses a micro-replication structure coated abrasive and a preparation method thereof. The present invention adopts allyl etherified phenolic resin as an adhesive, adds epoxy resin or polyurethane as a curing agent, adds a photoinitiator, reactive diluent and the like and mixes them evenly, then adds abrasive, filler and other powders, and uses a surface micro-replication pattern steel roller through a roller machine to make the product surface have a precise micro-pattern. The photothermal dual-curing micro-replication structure coated abrasive prepared by the present invention not only has a higher coating height than a single photoinitiator system resin binder, but also has a larger usable volume per unit area, and thus has a better service life. At the same time, due to the use of a modified phenolic resin system, the advantages of high surface hardness and good heat resistance of the phenolic resin are maintained, and the resin has higher bonding strength and tensile strength, which is suitable for high-efficiency and high-precision grinding of difficult-to-process metal materials and hard and brittle materials such as titanium alloys, engineering ceramics, and microcrystalline glass.

Description

Technical Field

[0001] The present invention relates to the field of coated abrasive tool preparation, in particular to a coated abrasive tool with a micro-replication structure and a preparation method thereof. Background Art

[0002] In recent years, flexible grinding and polishing technology, primarily belt grinding, has experienced rapid development, evolving from its initial focus on grinding ordinary surfaces with standard precision to the high-efficiency, high-precision machining of complex free-form surfaces. It now meets the precision and ultra-precision machining requirements of various complex free-form surfaces. In modern industry, belt grinding can process nearly all engineering materials and is known as "universal grinding" and "cold grinding" in advanced manufacturing technologies.

[0003] Compared to traditional abrasive belts, micro-replicated abrasive belts increase the number and quantity of abrasive layers by fixing the abrasive in tiny units, thereby extending the belt's service life. This multi-layer abrasive structure ensures that new abrasive is always exposed during the grinding process, thereby ensuring a high and stable material removal rate, high grinding efficiency, and consistent workpiece surface quality throughout the entire grinding process, thereby guaranteeing grinding quality. Traditional abrasive belts, on the other hand, have a single-layer abrasive structure. Such single-layer abrasive belts often have a high material removal rate at the beginning of the grinding process, but the material removal rate decreases significantly as the grinding progresses. This is because a single-layer abrasive belt initially has strong cutting ability due to the exposed abrasive cutting edge, but as the grinding progresses, the cutting edge wears and breaks, or the entire abrasive falls off. This results in a low material removal rate, low service life, and unstable grinding effect for these traditional single-layer abrasive belts.

[0004] Liu Lijun et al. (CN108481217A) developed a pyramid-shaped three-dimensional grinding tool for grinding metal mobile phone middle frames. First, diamond abrasives, photocuring adhesives (polyurethane acrylates), reactive diluents (acrylic monomers), photoinitiators, and other additives are mixed evenly in a certain proportion and then coated on a pyramid-shaped mold. The abrasives are first cured by ultraviolet light and transferred to the substrate, and then thermally cured to obtain a three-dimensional grinding tool with a diamond pyramid structure, thereby improving the grinding efficiency and processing yield and reducing costs during the grinding process of high-strength metal mobile phone middle frames.

[0005] Fang Hong et al. (CN107225516A) mixed a photocurable resin, a thermosetting resin, a leveling resin, a photoinitiator, a thermal initiator, a filler, and an abrasive to produce a 3D abrasive. The mixture was then poured into a mold cavity and thermally cured to form a 3D abrasive layer, a pre-coated primer layer, and a leveling resin layer. The initial 3D abrasive tool was then photocured and finally demolded and thermally cured to produce the finished 3D abrasive tool. The photocurable and thermally mixed components exhibited strong adhesion, resulting in a 3D flexible abrasive with high strength and stability, preventing interlayer separation during use.

[0006] Xing Bo et al. (CN103978446B) designed a rapid prototyping device for abrasive tools with regularly arranged abrasives. The device first secures the tool carrier to a workbench for preheating. A motor then rotates the workbench, allowing powder formed in a hopper to pass through a vibrating screen and be spread flat on the carrier. A scraper then evenly smoothes the layer of material on the carrier, which is then cured using light curing. This device achieves orderly abrasive distribution on the tool, rapid prototyping, and a stable manufacturing process.

[0007] The aforementioned products essentially utilize polyurethane acrylate and epoxy acrylate oligomers, along with reactive diluents, photoinitiators, and various additives to form a light-curing adhesive. Microreplication coated abrasives are prepared by UV curing or UV curing followed by thermal curing. However, due to the limitations of the oligomers used, most of the prepared microreplication coated abrasives exhibit poor heat resistance, low flexibility, and low surface hardness, making them suitable only for applications requiring low grinding forces, such as precision grinding and polishing.

[0008] Phenolic resins commonly used in coated abrasives have good surface hardness and heat resistance, making them particularly suitable for high-speed and high-efficiency grinding. Unmodified phenolic resins are high molecular weight polymers obtained by polycondensation of phenol and formaldehyde under acid or base catalysis. Currently, the industry uses different ratios of phenol and aldehyde and different catalyst pH values ​​to produce two types of phenolic resins: thermoplastic (linear) phenolic resins and thermosetting phenolic resins. Thermoplastic phenolic resins, also known as solid phenolic resins or Novolak resins, have linear or branched molecular chains and cannot undergo cross-linking reactions when heated. A curing agent such as hexamethylenetetramine must be added to form a cross-linked resin. Thermosetting phenolic resins, also known as liquid phenolic resins or Resol resins, undergo cross-linking reactions when heated and under acidic conditions, ultimately forming an insoluble and infusible cross-linked resin. However, general phenolic resins do not have double bonds in their molecular structure and cannot be photocured. Although surface micro-replication patterns can be achieved using a single thermal curing method, the thermal curing of the resin requires a process of first melting, thinning the viscosity, and then gradually solidifying through a cross-linking reaction. Therefore, continuous production cannot be achieved. The only process route is to form the resin in a mold, thermally cure it, and then demold it, resulting in low preparation efficiency.

[0009] Therefore, it is a technical problem that technicians in this field urgently need to solve to provide a micro-replicated structure coated abrasive tool and its preparation method with advantages such as high surface hardness and high strength, which is suitable for use in the grinding of difficult-to-process metal materials and hard and brittle materials such as titanium alloys, engineering ceramics, and microcrystalline glass. Summary of the Invention

[0010] In view of this, the present invention provides a micro-replicated structure coated abrasive and a preparation method thereof.

[0011] To achieve the above object, the present invention adopts the following technical solutions:

[0012] A micro-replication structure coated abrasive tool comprises the following raw materials in percentage by mass: 15-50% adhesive, 0.1-5% photoinitiator, 5-30% active diluent, 0-0.5% defoamer, 15-50% curing agent, 10-60% abrasive, and 0-20% filler.

[0013] Furthermore, the adhesive is allyl etherified modified phenolic resin.

[0014] Furthermore, in the scheme of the present invention, in order to enable the phenolic resin to be cross-linked by light curing, it is necessary to graft double bond functional groups into the phenolic resin molecules. The present invention utilizes the phenolic hydroxyl groups on phenol to undergo a condensation reaction, utilizes allyl chloride to react with the phenolic resin, and synthesizes allyl etherified phenolic resin, with an etherification rate between 0% and 50%.

[0015] Its synthetic route is:

[0016]

[0017] The beneficial effect of adopting this further embodiment is that the allyl etherified modified phenolic resin employed in the present invention, due to its unsaturated double bonds, can be polymerized under ultraviolet light under the action of a photoinitiator. Furthermore, the remaining methylol groups and phenolic hydroxyl groups can react with epoxy groups or isocyanate groups at high temperatures, achieving both photo- and thermally initiated free radical polymerization.

[0018] Furthermore, the photoinitiator is any one of benzoin and its derivatives, benzil and its derivatives, acetophenone and its derivatives, α-hydroxyalkyl acetophenone, α-aminoalkyl acetophenone, and acylphosphine oxide, or a mixture of several of them.

[0019] Furthermore, the acylphosphine oxide is 2,4,6-trimethylbenzoyl-ethoxy-phenylphosphine oxide.

[0020] Furthermore, the active diluent is any one of n-butyl acrylate, isooctyl acrylate, isodecyl acrylate, lauryl acrylate, hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, n-vinyl pyrrolidone, ethylene glycol diacrylate, propylene glycol diacrylate, or a mixture of several thereof.

[0021] Furthermore, the defoaming agent is any one of polydimethylsilicone, diethylhexanol, isooctyl alcohol, isopentanol, and diisobutyl carbinol.

[0022] Furthermore, the curing agent is epoxy resin or polyurethane resin.

[0023] The beneficial effect of adopting the above further solution is that the curing agent used in the present invention can undergo a heat curing reaction with the phenolic resin at a high temperature, thereby improving the impact resistance and bonding strength of the allyl etherified phenolic resin.

[0024] Furthermore, the abrasive is a mixture of any one or more of artificial diamond, cubic boron nitride, corundum and silicon carbide.

[0025] Furthermore, the corundum is white corundum, brown corundum, single crystal corundum, zirconium corundum or SG abrasive.

[0026] Furthermore, the filler is a mixture of any one or more of copper, copper alloy powder, calcium oxide, zinc oxide, chromium oxide, cryolite, potassium fluoroborate, bentonite, clay, kaolin, wollastonite powder, talc powder, mica powder, silica, barite, barium sulfate, gypsum powder, alumina powder, calcium sulfate, calcium carbonate, and magnesium carbonate.

[0027] The present invention also provides a method for preparing the above-mentioned micro-replicated structure coated abrasive tool, comprising the following steps:

[0028] (1) Weigh each raw material according to the above mass percentage;

[0029] (2) After uniformly mixing the adhesive, photoinitiator, reactive diluent, curing agent, and defoamer, abrasive and filler are added to obtain a mixture, which is then set aside;

[0030] (3) applying the mixture on a substrate to prepare a pre-coated product, and heating the pre-coated product on a flat line by infrared heating to remove water and solvent;

[0031] (4) The pre-coated product is subjected to roller patterning by a roller machine, and after the roller patterning, it is irradiated with ultraviolet light for photocuring and shaping, and then the shaped product is placed in a blast oven for drying to obtain a micro-replicated structure coated abrasive tool.

[0032] Furthermore, the substrate in step (3) is any one of a paper substrate, a cloth substrate, a steel paper, a PET film substrate, and a composite substrate.

[0033] Furthermore, the paper base is chemical fiber paper, fiber synthetic paper, film synthetic paper, etc.

[0034] The cloth base is cotton cloth, linen cloth, synthetic fiber cloth, blended cloth, nylon fiber cloth, polyester fiber cloth, etc.

[0035] Furthermore, the infrared heating temperature in step (3) is 100-120° C., and the heating time is 5-10 minutes.

[0036] Furthermore, the light curing in step (4) is curing under ultraviolet light for 3 to 10 minutes;

[0037] The blower drying temperature is 100-120°C and the drying time is 6-8 hours.

[0038] Furthermore, the roller machine described in the present invention is a rubber roller and a steel roller that cooperate with each other. According to the grinding purpose and process, various micro-replication patterns are engraved on the surface of the steel roller. During the preparation process, the roller machine uses the steel roller with the surface micro-replication pattern to perform roller flower treatment, so that the product surface has a precise micro-pattern.

[0039] The beneficial effects of the present invention are that the photothermal dual-curing micro-replicated structure coated abrasives produced by the present invention not only achieve a higher coating height than resin binders based on a single photoinitiator system, but also boast a larger usable volume per unit area, resulting in a longer service life. Furthermore, the use of a modified phenolic resin system maintains the advantages of phenolic resin's high surface hardness and excellent heat resistance, while also achieving higher bond strength and tensile strength. This makes the system suitable for high-efficiency, high-precision grinding of difficult-to-machine metal materials and hard and brittle materials, such as titanium alloys, engineering ceramics, and glass-ceramics. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 White light interference diagram of the glass-ceramic back panel before and after grinding in Example 1 of the present invention (a) is a comparison diagram before grinding and (b) after grinding;

[0041] Figure 2 The white light interference diagram of the microcrystalline glass back panel before and after grinding in Example 2 of the present invention (a) is a comparison diagram before grinding and (b) after grinding. DETAILED DESCRIPTION

[0042] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0043] In the embodiments of the present invention, allyl etherified phenolic resins are prepared by the following method:

[0044] Add thermoplastic phenolic resin powder and N,N-dimethylformamide (DMF) in a mass ratio of 1:1.2 to a three-necked flask and stir evenly. When the solution becomes clear and transparent, add allyl chloride and sodium hydroxide aqueous solution (at a molar ratio of 1:0.6:0.3 to phenol) into a dropping funnel and slowly drip into the three-necked flask. Complete the solution within 1 hour. React at 40°C for 3 hours, then heat to 50°C and react for another 3 hours. Discharge the material when the solution becomes a dark red viscous liquid. After refining, allyl-etherified phenolic resins with different etherification rates can be obtained.

[0045] Example 1

[0046] (1) Weigh the raw materials in Table 1:

[0047] Table 1

[0048]

[0049] (2) After uniformly mixing the adhesive, photoinitiator, reactive diluent, and curing agent, abrasive and filler are added to obtain a mixture for standby use;

[0050] (3) The mixture is applied on a substrate to prepare a pre-coated product, and the pre-coated product is heated on a flat line by infrared rays at 120°C for 5 minutes to remove water and solvent;

[0051] (4) The pre-coated product is subjected to roller patterning by a roller machine, and after the patterning, it is irradiated with ultraviolet light for UV curing and shaping for 3 minutes, and then the shaped product is placed in a blower and dried at 120°C for 8 hours to obtain a micro-replicated structure coated abrasive.

[0052] Tests show that the surface cube micro-replication diamond abrasive belt of Example 1 has a grinding layer depth of 0.62um, polishes microcrystalline glass, has a grinding pressure of 0.05MPa, a grinding speed of 1500rpm, a diamond abrasive disc grinding rate of 6.8mg / s, and a surface roughness Ra reduced from 1.234μm to 0.035μm. The polishing life exceeds 12 hours, and has the advantages of high polishing efficiency and long life.

[0053] Example 2

[0054] (1) Weigh the raw materials in Table 2:

[0055] Table 2

[0056]

[0057] (2) After uniformly mixing the adhesive, photoinitiator, reactive diluent, and curing agent, abrasive and filler are added to obtain a mixture for standby use;

[0058] (3) The mixture is applied on a substrate to prepare a pre-coated product, and the pre-coated product is heated on a flat line at 100°C for 10 minutes by infrared rays to remove water and solvent;

[0059] (4) The pre-coated product is subjected to roller patterning by a roller machine, and after the patterning, it is irradiated with ultraviolet light for UV curing and shaping for 10 minutes, and then the shaped product is placed in a blower and dried at 120°C for 8 hours to obtain a micro-replicated structure coated abrasive.

[0060] Tests showed that the hexahedral micro-replication CBN disc coating of Example 2, when used to polish titanium alloy at a grinding pressure of 0.05 MPa and a grinding speed of 1500 rpm, achieved a CBN disc removal rate of 4.4 mg / s, reducing the surface roughness Ra from 0.370 μm to 0.092 μm. The grinding life exceeded 12 hours, demonstrating high grinding efficiency and long life.

[0061] Test example

[0062] According to the technical solution of Example 1, different adhesive systems were used to prepare micro-replicated structure coated abrasives and their performance was compared. The results are shown in Table 3.

[0063] Table 3 Comparison of performance of micro-replicated coated abrasives with different adhesive systems

[0064]

[0065] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A micro-replicated coated abrasive, characterized in that: The raw materials include the following percentage by weight: adhesive 15-50%, photoinitiator 0.1-5%, active diluent 5-30%, defoamer 0-0.5%, curing agent 15-50%, abrasive 10-60%, filler 0-20%; The adhesive is allyl etherified modified phenolic resin; Among them, double bond functional groups are grafted into the phenolic resin molecules, specifically, a condensation reaction occurs on the phenolic hydroxyl groups on phenol, and allyl chloride reacts with the phenolic resin to synthesize allyl etherified phenolic resin, and its etherification rate is 0%~50%.

2. The micro-replicated structure coated abrasive according to claim 1, characterized in that: The photoinitiator is any one of benzoin and its derivatives, benzil and its derivatives, acetophenone and its derivatives, α-hydroxyalkyl acetophenone, α-aminoalkyl acetophenone, and acylphosphine oxide, or a mixture of several thereof. The active diluent is any one of n-butyl acrylate, isooctyl acrylate, isodecyl acrylate, lauryl acrylate, hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, n-vinyl pyrrolidone, ethylene glycol diacrylate, propylene glycol diacrylate, or a mixture of several of them.

3. The micro-replicated structure coated abrasive according to claim 1, characterized in that: The defoaming agent is any one of polydimethylsilicone, diethylhexanol, isooctyl alcohol, isopentanol, and diisobutyl carbinol; The curing agent is epoxy resin or polyurethane resin.

4. The micro-replicated structure coated abrasive according to claim 1, wherein: The abrasive is a mixture of any one or more of artificial diamond, cubic boron nitride, corundum and silicon carbide.

5. The micro-replicated structure coated abrasive according to claim 1, wherein: The filler is a mixture of any one or more of copper, copper alloy powder, calcium oxide, zinc oxide, chromium oxide, cryolite, potassium fluoroborate, bentonite, clay, kaolin, wollastonite powder, talc powder, mica powder, silicon dioxide, barite, barium sulfate, gypsum powder, alumina powder, calcium sulfate, calcium carbonate, and magnesium carbonate.

6. A method for preparing a micro-replicated structure coated abrasive tool, characterized in that: The following steps are involved: (1) Weigh the raw materials according to the mass percentages described in any one of claims 1 to 5; (2) After the adhesive, photoinitiator, active diluent, curing agent and defoaming agent are mixed evenly, abrasive and filler are added to obtain a mixture for standby use; (3) The mixture is scraped onto a substrate to prepare a pre-coated product, and the pre-coated product is heated on a flat line by infrared rays to remove water and solvent; (4) The pre-coated product is subjected to roller processing by a roller machine, and after roller processing, it is irradiated with ultraviolet light for photocuring and shaping. The shaped product is then placed in a blast oven for drying to obtain a micro-replicated structure coated abrasive.

7. The method for preparing a micro-replicated structure coated abrasive according to claim 6, wherein: The substrate in step (3) is any one of a paper substrate, a cloth substrate, a steel paper substrate, a PET film substrate, and a composite substrate.

8. The method for preparing a micro-replicated structure coated abrasive according to claim 6, wherein: The infrared heating temperature in step (3) is 100-120°C, and the heating time is 5-10 minutes.

9. The method for preparing a micro-replicated structure coated abrasive according to claim 6, wherein: The light curing in step (4) is performed under ultraviolet light for 3 to 10 minutes; The blower drying temperature is 100-120° C., and the drying time is 6-8 hours.

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