Process for the preparation of bio-based epoxy resins and their use in diamond cleaning pads

Abstract

This invention relates to the field of polymer materials technology, specifically to a method for preparing a bio-based epoxy resin and its application in diamond cleaning pads. The preparation method involves dissolving tannic acid in tetrahydrofuran, then adding bio-based 1,5-pentanediisocyanate and an organotin catalyst to obtain terminal isocyanate tannic acid; redissolving the terminal isocyanate tannic acid in tetrahydrofuran, then adding glycidol and an organotin catalyst to obtain a tannic acid-based bio-based epoxy resin. This invention, on the one hand, uses fully bio-based raw materials to form a bio-based epoxy resin structure, resulting in healthy chemical composition of the grinding debris generated during polishing, exhibiting environmentally friendly and healthy characteristics; on the other hand, due to its rigid multi-benzene ring structure, polyurethane structure, and multi-hydroxyl structure, the cured product possesses excellent mechanical strength and toughness, while also exhibiting high temperature resistance and adhesion. The resulting diamond abrasive has good polishing precision, polishing efficiency, and service life.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, specifically to a method for preparing a bio-based epoxy resin and its application in diamond cleaning pads. Background Technology

[0002] Diamond resin tools, due to their excellent sharpness and simple manufacturing process, have important applications in flooring, industrial equipment, and electronics. Epoxy resin, a thermosetting polymer material with excellent comprehensive properties, is widely used in engineering structural materials, adhesives, coatings, and other fields. Similarly, due to its good mechanical strength, adhesion, and heat resistance, it plays an important role in the production of diamond resin tools. Currently, the commonly used epoxy resin in diamond resin tools is bisphenol A (BPA) type epoxy resin. However, the BPA component in the microplastic abrasive debris produced by BPA may interfere with the endocrine system. Therefore, finding a healthy and environmentally friendly epoxy resin binder is of great significance.

[0003] Currently, there are numerous reports on the development of bio-based epoxy resins. CN118406023A reports a novel trifunctional bio-based epoxy resin based on bisphenol A, an epoxy resin coating, and a method for its preparation. CN110408003B reports a method for preparing a bio-based epoxy resin based on a natural magnolia officinalis derivative. However, these methods are not based on the application of epoxy resins in a specific field such as abrasives, and therefore often do not consider the influence of factors such as adhesion and processability on the application.

[0004] Tannic acid is a natural compound with a rigid polybenzene ring structure and polyphenolic hydroxyl groups, making it a good raw material for preparing bio-based epoxy resins. Current reports indicate two methods for introducing tannic acid into epoxy resin systems: physical addition and chemical modification. CN117844419A reports the preparation of rapidly curing and high tensile strength epoxy resin adhesives from bio-polyphenols (containing tannic acid) through physical addition. While physical addition is simple and effective, high-content additions cannot be achieved due to limitations in processing performance. CN110256655A reports a tannic acid-based polyfunctional epoxy resin and its preparation method, while CN119751819A also discloses a tannic acid-based epoxy resin and its application in anti-corrosion coatings. However, although an excessively high tannic acid content can significantly improve the strength and modulus of epoxy resin, as a binder for diamond cleaning pads, epoxy resin often needs to have a certain degree of flexibility to facilitate the adhesion of the diamond cleaning pad to the object being treated during construction. At the same time, the adhesion performance to diamond is also an important performance characteristic in the application of epoxy resin.

[0005] Therefore, based on the tannic acid structure, it is of great significance to regulate and design the structure of epoxy resin to meet the performance requirements of diamond cleaning pads. Currently, there is limited research on bio-based epoxy resin matrices suitable for diamond cleaning pads, and no specific theoretical framework for epoxy resin structure and performance has been established. Summary of the Invention

[0006] The purpose of this invention is to provide a method for preparing bio-based epoxy resin and its application in diamond cleaning pads, which has the characteristics of being environmentally friendly and healthy, and has good polishing precision, polishing efficiency and service life.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0008] The preparation method of bio-based epoxy resin includes the following steps:

[0009] (1) Dissolve tannic acid in tetrahydrofuran to obtain a solution, then add bio-based 1,5-pentanediisocyanate and organotin catalyst, react for 2-6 hours under stirring, remove tetrahydrofuran by rotary evaporation, and prepare terminal isocyanate tannic acid.

[0010] (2) The terminal isocyanate tannic acid is redissolved in tetrahydrofuran, and glycidol and organotin catalyst are slowly added. The reaction is carried out for 2-8 hours with stirring, and tetrahydrofuran is removed by rotary evaporation to obtain a bio-based epoxy resin based on tannic acid.

[0011] The structural formula of the bio-based epoxy resin is as follows:

[0012] .

[0013] Preferably, in step (1), the molar ratio of tannic acid to bio-based 1,5-pentanediisocyanate is 1:0.5-6.

[0014] Preferably, in step (2), the molar ratio of the terminal isocyanate tannic acid to glycidol is 1:1-10.

[0015] The present invention also provides the application of the bio-based epoxy resin prepared by the above preparation method as a resin binder in diamond cleaning pads.

[0016] Preferably, the raw material composition of the diamond cleaning pad is as follows: 100 parts of bio-based epoxy resin, 5-80 parts of bio-based active diluent, 30-100 parts of cashew phenol amine curing agent, 20-50 parts of diamond, 10-50 parts of auxiliary abrasive, and 15-30 parts of inorganic filler.

[0017] Preferably, the bio-based active diluent is one or a combination of several of epoxidized soybean oil, cashew phenol glycidyl ether, and polyethylene glycol diglycidyl ether.

[0018] Preferably, the diamond has a size of 5μm to 300μm; the auxiliary abrasive is one or more of silicon carbide, alumina, zirconium oxide, boron nitride and cerium oxide, and the size of the auxiliary abrasive is 3μm to 200μm.

[0019] Preferably, the inorganic filler is one or more of talc, calcium carbonate, silica, glass fiber powder, aramid pulp and hollow glass microspheres, and the size of the inorganic filler is 1μm to 50μm.

[0020] Preferably, the diamond cleaning pad is prepared by: preparing a pad material, which is made of a biodegradable material; mixing the raw materials of the cleaning pad and stirring evenly to obtain a mixture; coating or spraying the mixture onto the surface of the pad material; and curing to obtain a diamond cleaning pad, with a curing temperature of 90℃-105℃ and a curing time of 1.5 hours-3 hours.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] This invention introduces bio-based 1,5-pentanediisocyanate and tannic acid structures into an epoxy resin prepolymer system to prepare a bio-based epoxy resin, which is then applied to diamond cleaning pads. On the one hand, the fully bio-based raw materials react to form a bio-based epoxy resin structure, which has a natural polymer structure. The chemical composition of the abrasive debris generated during grinding and polishing is healthy, reducing the impact on the environment and ecosystem, thus giving it environmentally friendly and healthy characteristics. On the other hand, due to the rigid polybenzene ring structure, polyurethane structure, and polyhydroxy structure, the cured product has excellent mechanical strength and toughness, as well as high temperature resistance and adhesion. The diamond cleaning pad prepared with the obtained bio-based epoxy resin as the matrix resin has good polishing precision, polishing efficiency, and service life. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the chemical synthesis of the bio-based epoxy resin of this invention.

[0024] Figure 2 This is the structural formula of tannic acid in this invention.

[0025] Figure 3 The structure of the terminal isocyanate tannic acid of this invention is shown below.

[0026] Figure 4 This invention relates to the structural formula of a bio-based epoxy resin based on tannic acid. Detailed Implementation Example 1

[0027] This embodiment provides a diamond cleaning pad based on bio-based epoxy resin, the preparation method of which includes the following steps:

[0028] S1. Preparation of bio-based epoxy resin:

[0029] S11. Using a molar measuring instrument, dissolve 1 mol of tannic acid in 1 L of tetrahydrofuran to obtain a tetrahydrofuran solution of tannic acid. Then add 3 mol of bio-based 1,5-pentanediisocyanate and 0.002 mol of organotin catalyst. React under stirring for 3 hours. Remove tetrahydrofuran by rotary evaporation to prepare terminal isocyanate tannic acid.

[0030] S12. The 1 mol terminal isocyanate tannic acid prepared above is redissolved in 1 L tetrahydrofuran, 4 mol glycidol and 0.002 mol organotin catalyst are slowly added, and the reaction is carried out for 4 hours with stirring. The tetrahydrofuran is removed by rotary evaporation to obtain a bio-based epoxy resin based on tannic acid.

[0031] S2. Preparation of Diamond Cleaning Pads

[0032] S21. Material preparation: By weight, prepare 100 parts of bio-based epoxy resin, 10 parts of epoxidized soybean oil, 60 parts of cashew phenolic amine curing agent, 50 parts of 10μm diamond, 25 parts of 40μm silicon carbide, 15 parts of 30μm alumina, 10 parts of 10μm boron nitride, 10 parts of 10μm talc, 10 parts of 5μm silica, and 5 parts of aramid pulp; also prepare a padding material, which is a non-woven fabric made of biodegradable nylon fiber.

[0033] S22. A mixture is obtained by mixing and stirring bio-based epoxy resin, epoxy soybean oil, cashew phenol amine curing agent, diamond, silicon carbide, alumina, boron nitride, talc, silicon dioxide, and aramid pulp.

[0034] S23. Coat the surface of the padding material with the mixture.

[0035] S24. Curing in an oven at 98°C for 2 hours. Example 2

[0036] This embodiment provides a diamond cleaning pad based on bio-based epoxy resin, the preparation method of which includes the following steps:

[0037] S1. Preparation of bio-based epoxy resin:

[0038] S11. Using a molar measuring instrument, dissolve 1 mol of tannic acid in 1 L of tetrahydrofuran to obtain a tetrahydrofuran solution of tannic acid. Then add 3 mol of bio-based 1,5-pentanediisocyanate and 0.002 mol of organotin catalyst. React under stirring for 3 hours. Remove tetrahydrofuran by rotary evaporation to prepare terminal isocyanate tannic acid.

[0039] S12. The 1 mol terminal isocyanate tannic acid prepared above is redissolved in 1 L tetrahydrofuran, 4 mol glycidol and 0.002 mol organotin catalyst are slowly added, and the reaction is carried out for 4 hours with stirring. The tetrahydrofuran is removed by rotary evaporation to obtain a bio-based epoxy resin based on tannic acid.

[0040] S2. Preparation of Diamond Cleaning Pads

[0041] S21. Material preparation: By weight, prepare 100 parts of bio-based epoxy resin, 15 parts of cashew phenol glycidyl ether, 50 parts of cashew phenol aldehyde amine curing agent, 50 parts of 10μm diamond, 25 parts of 40μm silicon carbide, 15 parts of 30μm alumina, 8 parts of 10μm zirconium oxide, 10 parts of 10μm talc, 10 parts of 5μm silica, and 5 parts of glass fiber powder; and also prepare padding material, which is a non-woven fabric made of biodegradable nylon fiber.

[0042] S22. A mixture is prepared by mixing and stirring bio-based epoxy resin, cashew phenol glycidyl ether, cashew phenol aldehyde amine curing agent, diamond, silicon carbide, alumina, zirconium oxide, talc, silica, and glass fiber powder.

[0043] S23. Coat the surface of the padding material with the mixture.

[0044] S24. Curing in an oven at 98°C for 2 hours. Example 3

[0045] This embodiment provides a diamond cleaning pad based on bio-based epoxy resin, the preparation method of which includes the following steps:

[0046] S1. Preparation of bio-based epoxy resin:

[0047] S11. Using a molar measuring instrument, dissolve 1 mol of tannic acid in 1 L of tetrahydrofuran to obtain a tetrahydrofuran solution of tannic acid. Then add 3 mol of bio-based 1,5-pentanediisocyanate and 0.002 mol of organotin catalyst. React under stirring for 3 hours. Remove tetrahydrofuran by rotary evaporation to prepare terminal isocyanate tannic acid.

[0048] S12. The 1 mol terminal isocyanate tannic acid prepared above is redissolved in 1 L tetrahydrofuran, 4 mol glycidol and 0.002 mol organotin catalyst are slowly added, and the reaction is carried out for 4 hours with stirring. The tetrahydrofuran is removed by rotary evaporation to obtain a bio-based epoxy resin based on tannic acid.

[0049] S2. Preparation of Diamond Cleaning Pads

[0050] S21. Material preparation: By weight, prepare 100 parts of bio-based epoxy resin, 20 parts of polyethylene glycol diglycidyl ether, 45 parts of cashew phenolic amine curing agent, 50 parts of 10μm diamond, 20 parts of 40μm silicon carbide, 10 parts of 30μm alumina, 5 parts of 10μm cerium oxide, 15 parts of 10μm talc, and 10 parts of 5μm calcium carbonate; and also prepare a padding material, which is a non-woven fabric made of biodegradable nylon fiber.

[0051] S22. Mix bio-based epoxy resin, polyethylene glycol diglycidyl ether, cashew phenol amine curing agent, diamond, silicon carbide, alumina, cerium oxide, talc, and calcium carbonate to obtain a mixture.

[0052] S23. Spray the mixture onto the surface of the pad material.

[0053] S24. Curing in an oven at 98°C for 2 hours.

[0054] Comparative Example 1

[0055] By weight, 100 parts of bisphenol A epoxy resin, 80 parts of modified methyl hexahydrophthalic anhydride, 50 parts of 10μm diamond, 25 parts of 40μm silicon carbide, 15 parts of 30μm alumina, 10 parts of 10μm boron nitride, 10 parts of 10μm talc, 10 parts of 5μm silica, and 5 parts of aramid pulp are mixed evenly. The mixture is then coated onto the surface of the pad material and kept at 120℃ for 4 hours, and then heated to 160℃ and kept for 8 hours to obtain a diamond cleaning pad.

[0056] To better illustrate the polishing effect of the present invention, samples from Examples 1-3 and Comparative Example 1 were tested. Gray marble was used as the test surface, and dry polishing was performed using a KlindexRockey polishing machine (41 kg, 250 rpm). The gloss, clarity, and abrasion of the cleaning pad on the marble surface were then measured.

[0057] Table 1: Gloss and clarity of samples from Examples 1-3 and Comparative Example 1 of the present invention

[0058]

[0059] As shown in Table 1, the diamond cleaning pads (Examples 1-3) prepared with the bio-based epoxy resin of the present invention as the matrix have comparable performance and service life to the diamond cleaning pads (Comparative Example 1) prepared with commonly used bisphenol A epoxy resin.

[0060] As can be seen from the above embodiments, the present invention provides a preparation of bio-based epoxy resin and its application in diamond cleaning pads. The diamond cleaning pad prepared using the bio-based epoxy resin of the present invention as the matrix has the advantages of being environmentally friendly, having good polishing effect, and having a long service life.

[0061] The foregoing has shown and described the basic principles, main features and advantages of this invention. Those skilled in the art should understand that this invention is not limited to the above embodiments. The embodiments and descriptions in the specification are only illustrative of the principles of this invention. Various changes and modifications can be made to this invention without departing from the spirit and scope of this invention. All such changes and modifications fall within the scope of this invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing bio-based epoxy resin, characterized in that, Includes the following steps: (1) Dissolve tannic acid in tetrahydrofuran to obtain a solution, then add bio-based 1,5-pentanediisocyanate and organotin catalyst, react for 2-6 hours under stirring, remove tetrahydrofuran by rotary evaporation, and prepare terminal isocyanate tannic acid. (2) The terminal isocyanate tannic acid is redissolved in tetrahydrofuran, and glycidol and organotin catalyst are slowly added. The reaction is carried out for 2-8 hours with stirring, and tetrahydrofuran is removed by rotary evaporation to obtain a bio-based epoxy resin based on tannic acid.

2. The method for preparing the bio-based epoxy resin according to claim 1, characterized in that: The structural formula of the bio-based epoxy resin is as follows: 。 3. The method for preparing the bio-based epoxy resin according to claim 1, characterized in that: In step (1), the molar ratio of tannic acid to bio-based 1,5-pentanediisocyanate is 1:0.5-6.

4. The method for preparing the bio-based epoxy resin according to claim 1, characterized in that: In step (2), the molar ratio of terminal isocyanate tannic acid to glycidol is 1:1-10.

5. The application of the bio-based epoxy resin prepared by the method of claim 1 as a resin binder in diamond cleaning pads.

6. The application according to claim 5, characterized in that: The raw material composition of the diamond cleaning pad is as follows: 100 parts of bio-based epoxy resin, 5-80 parts of bio-based active diluent, 30-100 parts of cashew phenol amine curing agent, 20-50 parts of diamond, 10-50 parts of auxiliary abrasive, and 15-30 parts of inorganic filler; wherein the bio-based epoxy resin is a bio-based epoxy resin prepared by the preparation method described in any one of claims 1 to 4.

7. The application according to claim 6, characterized in that: The bio-based active diluent is one or a combination of several of epoxidized soybean oil, cashew phenol glycidyl ether, and polyethylene glycol diglycidyl ether.

8. The application according to claim 6, characterized in that: The diamond has a size of 5μm to 300μm; the auxiliary abrasive is one or more of silicon carbide, alumina, zirconium oxide, boron nitride and cerium oxide, and the size of the auxiliary abrasive is 3μm to 200μm.

9. The application according to claim 6, characterized in that: The inorganic filler is one or more of talc, calcium carbonate, silica, glass fiber powder and hollow glass microspheres, and the size of the inorganic filler is 1μm~50μm.

10. The application according to claim 6, characterized in that: The diamond cleaning pad is prepared by: preparing pad material; mixing the raw materials of the cleaning pad and stirring evenly to obtain a mixture; coating or spraying the mixture onto the surface of the pad material; and curing to obtain the diamond cleaning pad.

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