A composite adhesive for abrasives and its preparation method

Abstract

This invention relates to C08K3 / 013, specifically to a composite adhesive for abrasives and its preparation method. It comprises the following raw materials: by weight, 100 parts phenolic resin, 10-20 parts vinyl ester resin, 2-5 parts filler, and 5-10 parts additives. The composite adhesive provided by this invention exhibits high toughness, good impact resistance, high tensile shear strength, and excellent mechanical properties, making it particularly suitable for sandpaper preparation and effectively improving the physical properties of sandpaper.

Description

Technical Field

[0001] This invention relates to C08K3 / 013, specifically to a composite adhesive for abrasives and its preparation method. Background Technology

[0002] Coated abrasives are abrasives for which abrasive particles are adhered to a flexible substrate using an adhesive. Sandpaper is one of the most commonly used flexible substrates for coated abrasives, and it is widely used for grinding, polishing, and sanding non-metallic materials such as metals, wood, ceramics, and plastics. Traditional epoxy resin coatings contain a large amount of organic solvents, which can easily pollute the environment and do not conform to modern green environmental protection concepts. Therefore, water-soluble phenolic resins are now more commonly used as coatings for abrasive particles.

[0003] Patent CN200910181790.7 provides a phenolic resin for coated abrasives and its preparation method. The phenolic resin for coated abrasives prepared by using various phenolic resins as raw materials and inorganic fillers, mixed solvents and other substances has high adhesion and high peel strength.

[0004] Patent CN201310734706.6 provides a thermoplastic phenolic resin for ultra-thin resin abrasives and its preparation method. The phenolic resin obtained by limiting the raw materials and preparation method of the phenolic resin has a high dispersion coefficient and good grinding performance.

[0005] However, while the water-soluble phenolic resin composite prepared above has excellent rigidity, heat resistance and aging resistance, it has poor flexibility, high brittleness, and is prone to cracking, making it difficult to apply to flexible substrates. Summary of the Invention

[0006] To solve the above-mentioned technical problems, the first aspect of the present invention provides a composite adhesive for abrasives, comprising the following raw materials: 100 parts by weight of phenolic resin, 10-20 parts by weight of vinyl ester resin, 2-5 parts by weight of filler, and 5-10 parts by weight of additives.

[0007] Preferably, the viscosity of the phenolic resin at 25°C is 500-700 mPa·s.

[0008] Preferably, the solid content of the phenolic resin is 70-80 wt%.

[0009] Preferably, the solvent for the phenolic resin is water.

[0010] Preferably, the vinyl ester resin is prepared by reacting bisphenol A type epoxy resin and / or phenolic epoxy resin with methacrylic acid.

[0011] More preferably, the vinyl ester resin is prepared by reacting phenolic epoxy resin with methacrylic acid.

[0012] Preferably, the viscosity of the vinyl resin at 25°C is 300-600 mPa·s.

[0013] Preferably, the solid content of the vinyl resin is 55-65 wt%.

[0014] Preferably, the vinyl resin has a gel time of 15-45 min at 25°C.

[0015] The slow curing speed and poor flexibility of pure phenolic resin are no longer sufficient to meet the requirements of modern abrasive coatings. This invention uses a vinyl resin prepared by reacting phenolic epoxy resin (with a viscosity of 300-600 mPa·s at 25°C, a solid content of 58-64 wt%, and a gel time of 15-45 min at 25°C) with methacrylic acid as the main raw material for abrasive coatings. This process, combined with phenolic resin, results in higher reactivity, greater crosslinking density, and faster curing speed. It effectively absorbs the energy generated by impacts, improving impact resistance and the grinding performance of abrasives.

[0016] Preferably, the particle size of the filler is ≤15µm.

[0017] Preferably, the filler includes at least one of alumina, silicon carbide, silicon dioxide, ceramic micro powder, titanium dioxide, and silicate.

[0018] More preferably, the filler comprises silica and ceramic micropowder. The mass ratio of silica to ceramic micropowder is (5-7):(2-4).

[0019] Preferably, the silica comprises fumed silica and / or precipitated silica.

[0020] More preferably, the silicon dioxide comprises fumed silicon dioxide.

[0021] Preferably, the specific surface area of ​​the silicon dioxide is 250-350 m². 2 / g.

[0022] Preferably, the tap density of the silica is 40-60 g / dm³. 3 .

[0023] More preferably, the particle size of the ceramic micro powder is 0.2-3 μm.

[0024] Preferably, the oil absorption rate of the ceramic micro powder is 55-80g / 100g.

[0025] Preferably, the tap density of the ceramic micro powder is 2.0-2.5 g / cm³. 3 .

[0026] Preferably, the additives include at least one of plasticizers, toughening agents, compatibilizers, coupling agents, penetrants, defoamers, and leveling agents.

[0027] More preferably, the additives include plasticizers, toughening agents, and coupling agents. The mass ratio of the plasticizer, toughening agent, and coupling agent is (5-7):(2-4):(2-4).

[0028] Preferably, the plasticizer includes at least one of phthalate plasticizers, fatty acid ester plasticizers, phosphate ester plasticizers, epoxy ester plasticizers, polyester plasticizers, and trimellitate plasticizers.

[0029] More preferably, the plasticizer includes phthalate plasticizers.

[0030] Preferably, the phthalate plasticizer includes at least one of diethyl phthalate, dioctyl phthalate, dibutyl phthalate, diisodecyl phthalate, and di(2-ethylhexyl) phthalate.

[0031] More preferably, the phthalate plasticizer includes dibutyl phthalate and diisodecyl phthalate. The mass ratio of dibutyl phthalate to diisodecyl phthalate is (5-7):(3-5).

[0032] While phenolic resin composites possess excellent rigidity, heat resistance, and aging resistance, they also exhibit poor flexibility, high brittleness, and a tendency to crack, making them unsuitable for flexible substrates. This invention addresses this issue by employing a compound plasticizer of dibutyl phthalate and diisodecyl phthalate to control the intermolecular forces within the system. This allows the molecular chains to maintain a certain degree of mobility, effectively avoiding the problems of insufficient flexibility and high brittleness after curing in composites used for abrasive tools. Especially when the mass ratio is (5-7):(3-5), it prevents insufficient dibutyl phthalate content, which can lead to poor compatibility between the plasticizer and phenolic resin and other raw materials, resulting in reduced toughness and tensile shear strength in the prepared composite. Consequently, the prepared composite is particularly suitable for flexible substrates.

[0033] Preferably, the toughening agent has a viscosity of 750-1200 mPa·s at 20°C and in a 10% wt ethanol solution.

[0034] Preferably, the content of vinyl butyral in the toughening agent is 72-82 wt%.

[0035] Preferably, the coupling agent includes KH570 and / or KH560.

[0036] The second aspect of the present invention provides a method for preparing a composite adhesive for abrasive tools, comprising the following steps: weighing each raw material by mass, mixing and stirring the raw materials in the system evenly, heating to 30-40℃ and continuing to stir for 0.5-1.5h to obtain the final product.

[0037] Beneficial effects:

[0038] 1) This invention provides a composite adhesive for abrasives and its preparation method. The composite adhesive prepared by limiting the content and specific types of each substance in the system has high toughness, good impact resistance, high tensile shear strength and good mechanical properties. It is especially suitable for the preparation of sandpaper and can effectively improve the physical properties of sandpaper.

[0039] 2) This invention utilizes vinyl resin prepared by reacting phenolic epoxy resin with methacrylic acid at a viscosity of 300-600 mPa·s at 25℃, a solid content of 58-64 wt%, and a gel time of 15-45 min at 25℃. This combined effect with phenolic resin effectively improves the shortcomings of pure phenolic resin, such as slow curing speed and poor flexibility. At the same time, it can effectively absorb the energy generated by impact, improve impact resistance and grinding performance of abrasives.

[0040] 3) This invention uses a plasticizer composed of dibutyl phthalate and diisodecyl phthalate, especially when the mass ratio of dibutyl phthalate to diisodecyl phthalate is (5-7):(3-5), which effectively avoids the problems of insufficient flexibility and high brittleness after curing of the composite adhesive used to prepare abrasives and molds, improves the compatibility between systems, and has better flexibility, especially suitable for flexible substrates.

[0041] 4) This invention also controls the particle size and tap density of the silica to 40-60 g / dm by specifying the specific types of silica and ceramic micropowder. 3 The tap density of the ceramic micro powder is 2.0-2.5 g / cm³. 3 This significantly improves its grinding performance, making it more suitable for use in abrasive coatings for grinding wheels.

[0042] 5) The sandpaper prepared by the abrasive of the present invention has high flexibility, tensile strength and tensile energy absorption, high folding resistance, good mechanical properties and high elongation at break. Detailed Implementation

[0043] Example

[0044] Example 1

[0045] A composite adhesive for abrasives comprises the following raw materials: 100 parts phenolic resin, 15 parts vinyl ester resin, 3 parts filler, and 7 parts additives by weight.

[0046] The phenolic resin has a viscosity of 600 mPa·s at 25°C, a solid content of 75 wt%, and is purchased from Sumitomo Bakelite Corporation, model number PR-53074, using water as the solvent.

[0047] The vinyl resin has a viscosity of 300-600 mPa·s at 25°C, a solid content of 58-64 wt%, and a gel time of 15-45 min at 25°C. The vinyl ester resin is prepared by reacting phenolic epoxy resin with methacrylic acid and is purchased from Wuxi Xinyehao Chemical Co., Ltd., model: XYH4000.

[0048] The filler comprises silica and ceramic micro powder. The mass ratio of silica to ceramic micro powder is 6:3.

[0049] The silica is fumed silica with a particle size ≤15µm and a specific surface area of ​​300±30m². 2 / g, tap density is 40-60g / dm³ 3 Purchased from Shandong Wanhua Tianhe New Materials Co., Ltd., model: TH-6300.

[0050] The ceramic micropowder has a particle size of 0.2-3 μm, an oil absorption rate of 55-80 g / 100 g, and a tap density of 2.3 g / cm³. 3 The Mohs hardness is 5, and it was purchased from Shanghai Huijing Asia Nanomaterials Co., Ltd.

[0051] The additives include plasticizers, toughening agents, and coupling agents. The mass ratio of the plasticizer, toughening agent, and coupling agent is 6:3:3.

[0052] The plasticizer is a phthalate plasticizer, which includes dibutyl phthalate and diisodecyl phthalate. The mass ratio of dibutyl phthalate to diisodecyl phthalate is 6:4.

[0053] The toughening agent has a viscosity of 750-1200 mPa·s at 20°C and in a 10wt% ethanol solution, and a vinyl butyral content of 72-82wt%. The toughening agent is polyvinyl butyral. It was purchased from Tianyuan Aviation Materials (Yingkou) Technology Co., Ltd., model: TB-12.

[0054] The coupling agent is KH570.

[0055] A method for preparing a composite adhesive for abrasive tools includes the following steps: weighing each raw material by mass, mixing and stirring the raw materials in the system until uniform, heating to 35°C and stirring for 1 hour to obtain the final product.

[0056] Example 2

[0057] A composite adhesive for abrasives, implemented in the same manner as in Example 1, except that the toughening agent has a viscosity of 400-750 mPa·s at 20°C and in a 10 wt% ethanol solution, and the content of polyvinyl butyral groups is 72-82 wt% polyvinyl butyral. Purchased from Tianyuan Aviation Materials (Yingkou) Technology Co., Ltd., model: TB-14.

[0058] Example 3

[0059] A composite adhesive for abrasives is described in the same way as in Example 1, except that the raw materials include 100 parts of phenolic resin, 20 parts of vinyl ester resin, 5 parts of filler, and 10 parts of additives.

[0060] Comparative Example 1

[0061] A composite adhesive for abrasives is described in the same manner as in Example 1, except that the mass ratio of dibutyl phthalate to diisodecyl phthalate is 3:4.

[0062] Comparative Example 2

[0063] A composite adhesive for abrasives is described, with the specific implementation method being the same as in Example 1, except that the vinyl ester resin has a viscosity of 200-600 mPa·s at 25°C, a solid content of 59-65 wt%, and a gel time of 10-50 min at 25°C. The vinyl ester resin is prepared by reacting bisphenol A epoxy resin with methacrylic acid and is purchased from Wuxi Xinyehao Chemical Co., Ltd., model: XYH3003.

[0064] Performance testing

[0065] 1. Toughness test: Impact strength test shall be conducted in accordance with GB / T1043.1-2008.

[0066] 2. Tensile shear strength test: Impact strength test shall be conducted in accordance with GB7124-2008-T.

[0067] 3. Physical property testing of sandpaper: The abrasive material prepared in Example 1 was coated onto sandpaper with adhesive, dried at 120°C for 20 minutes, and then cured at 115°C for 8 hours. The resulting sandpaper was then subjected to physical property testing according to JBT7498-2006.

[0068] Table 1 Performance Test Results

[0069]

[0070] Table 2 Performance test results of Example 1

[0071]

Claims

1. A coating for abrasives in grinding wheels, characterized in that, The raw materials include the following: by weight, 100 parts phenolic resin, 10-20 parts vinyl ester resin, 2-5 parts filler, and 5-10 parts additives; The viscosity of the phenolic resin at 25°C is 500-700 mPa·s; The solid content of the phenolic resin is 70-80 wt%. The vinyl ester resin has a viscosity of 300-600 mPa·s at 25°C, a solid content of 58-64 wt%, a gel time of 15-45 min at 25°C, and is model XYH4000. The additives include plasticizers, toughening agents, and coupling agents; The mass ratio of the plasticizer, toughening agent, and coupling agent is (5-7):(2-4):(2-4); The plasticizer includes phthalate plasticizers; The phthalate plasticizer comprises dibutyl phthalate and diisodecyl phthalate; the mass ratio of dibutyl phthalate to diisodecyl phthalate is (5-7):(3-5); The filler comprises silica and ceramic micro powder; the mass ratio of silica to ceramic micro powder is (5-7):(2-4); The specific surface area of ​​the silicon dioxide is 250-350 m². 2 / g; The tap density of the silica is 40-60 g / dm³. 3 ; The ceramic micro powder has a particle size of 0.2-3 μm; The oil absorption rate of the ceramic micro powder is 55-80g / 100g; The tap density of the ceramic micro powder is 2.0-2.5 g / cm³. 3 .

2. The adhesive for abrasives in grinding wheels according to claim 1, characterized in that, The filler particle size is ≤15μm.

3. A method for preparing a composite adhesive for abrasives according to claim 1, characterized in that, The process includes the following steps: weigh each raw material by weight, mix and stir the raw materials in the system until uniform, heat to 30-40℃ and continue stirring for 0.5-1.5 hours to obtain the final product.

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