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CN-122011983-A - Preparation method of bio-based composite adhesive, adhesive composition and abrasive cloth

CN122011983ACN 122011983 ACN122011983 ACN 122011983ACN-122011983-A

Abstract

The invention relates to the technical field of adhesives for coated abrasive tools, and discloses a preparation method of a bio-based composite adhesive, an adhesive composition and abrasive cloth, wherein the raw materials of the adhesive comprise phenol, formaldehyde solution, enzymolysis lignin, glycol, sodium hydroxide, ammonia water, urea, boric acid, other auxiliary agents and water according to parts by weight; the preparation method comprises pre-swelling and synthetic resin. The pre-swelling process of controlling the alkalinity through the cooperation of the ammonia water and the sodium hydroxide can not only realize the thorough activation of the enzymolysis lignin, but also cooperate with the low ash content characteristic of the enzymolysis lignin, ensure that the adhesive has extremely low ion mobility and stable dielectric constant, meet the requirement of the electrostatic sand planting process, and cooperate to realize the precise orientation of abrasive particles. The consumption of sodium hydroxide is reduced, the reduction of moisture absorption and thermal creep resistance of a glue layer caused by alkali metal ion residues is avoided, and the problem that conventional lignin is difficult to apply to an adhesive for high-precision abrasive cloth is solved.

Inventors

  • LIU CHUN

Assignees

  • 佛山市锐研磨料磨具有限公司

Dates

Publication Date
20260512
Application Date
20260302

Claims (10)

  1. 1. The preparation method of the bio-based composite adhesive is characterized by comprising the following raw materials in parts by weight: 180-240 parts of phenol, 320-410 Parts of 37% formaldehyde solution, 80-120 Parts of enzymatic hydrolysis lignin, 12-24 Parts of ethylene glycol, 1.5-4 Parts of sodium hydroxide, 4-10 Parts of 25% ammonia water, 1-3 Parts of urea, 2-5 Parts of boric acid, 0.02-11.55 Parts of other auxiliary agents; A proper amount of water; the preparation method comprises the following steps: Pre-swelling, namely stirring and mixing enzymolysis lignin, glycol, sodium hydroxide, ammonia water and water according to the proportion in the raw materials to prepare slurry with the water content of 10-20%, standing or stirring for 1-48 hours, and dispersing at a high speed for 0.5-1 hour to obtain pre-swollen slurry; synthetic resin: S1, adding water, phenol, formaldehyde solution and pre-swollen slurry into a reaction kettle according to the proportion of raw materials, stirring, mixing, heating and polymerizing for 2-10 hours to obtain modified phenolic resin; S2, vacuum decompression, drainage and exhaust are carried out on the reaction kettle, and the solid content of the modified phenolic resin in the reaction kettle is controlled to be 40-75%; s3, adding urea into the reaction kettle according to the proportion of the raw materials, and stirring for reaction for 10-30 minutes; S4, adding other auxiliary agents into the reaction kettle according to the proportion of the raw materials, cooling the reaction kettle to 20-40 ℃, finally adding boric acid into the reaction kettle to adjust the pH value to 7.5-9, and discharging to obtain the bio-based composite adhesive.
  2. 2. The method for preparing the bio-based composite adhesive according to claim 1, wherein in the pre-swelling step, materials are mixed and then stirred in a closed manner for 1-6 hours at 50-60 ℃, and then dispersed at a high speed to obtain pre-swelled slurry.
  3. 3. The method for preparing the bio-based composite adhesive according to claim 1, wherein in the pre-swelling step, materials are mixed and then are kept stand for 6-48 hours at normal temperature, and then dispersed at a high speed to obtain pre-swelled slurry.
  4. 4. The method for preparing the bio-based composite adhesive according to claim 1, wherein in the step S2 of synthesizing the resin, the vacuum degree of vacuum decompression is-0.08 to-0.095 MPa, the temperature is 50-60 ℃ and the time is 10-30 minutes.
  5. 5. The preparation method of the bio-based composite adhesive according to claim 1, wherein in the step S1 of the synthetic resin, water, phenol and pre-swollen slurry are added into a reaction kettle, the temperature is raised to 50-55 ℃, 10-30% of formaldehyde is added after the phenol is dissolved, the temperature is raised to 55-60 ℃, then the rest formaldehyde is slowly added dropwise within 1-3 hours, the temperature is raised to 65-75 ℃ after the dropwise addition is completed, and the reaction is continued for 0.5-2 hours, so that the heating polymerization is completed.
  6. 6. The method for preparing the bio-based composite adhesive according to claim 1, wherein the other auxiliary agents comprise at least one of a nonionic defoamer, an antioxidant and a toughening agent, wherein the nonionic defoamer comprises 0.02-0.05 part by mass, the antioxidant comprises 0.1-0.5 part by mass and the toughening agent comprises 1-5 parts by mass.
  7. 7. The method for preparing the bio-based composite adhesive according to claim 1, wherein the other auxiliary agent comprises at least one of triethanolamine and resorcinol, wherein the triethanolamine comprises 0.5-1 part by mass and the resorcinol comprises 2-5 parts by mass.
  8. 8. An adhesive composition is characterized by comprising 0.03-0.3 part by mass of polyether modified siloxane and an adhesive prepared by the preparation method of any one of claims 1-7.
  9. 9. The adhesive composition according to claim 8, further comprising 0.5 to 1.5 parts by mass of a silane coupling agent.
  10. 10. The abrasive cloth is characterized by comprising a base material, an abrasive material, a primer layer and a primer layer, wherein the primer layer is formed on one side surface of the base material, one end of the abrasive material is uniformly embedded in the primer layer, the primer layer is coated on the abrasive material and the primer layer, the primer layer and the primer layer are both coated by the bio-based composite adhesive prepared by the method of any one of claims 1-7, the solid content of the bio-based composite adhesive used for the primer layer is 55-75%, the viscosity is 1500-350 mpa.s, the solid content of the bio-based composite adhesive used for the primer layer is 40-60%, and the viscosity is 500-2000 mpa.s.

Description

Preparation method of bio-based composite adhesive, adhesive composition and abrasive cloth Technical Field The invention relates to the technical field of adhesives for coated abrasive tools, in particular to a preparation method of a bio-based composite adhesive, an adhesive composition and abrasive cloth. Background Phenolic resins have long been widely used as primary adhesives in the field of coated abrasive manufacture due to their excellent mechanical strength, heat resistance and chemical stability. In abrasive cloth manufacturing, the primer layer is responsible for anchoring the abrasive on the surface of the cloth base material, and the covering layer provides secondary reinforcement by wrapping the abrasive, and the abrasive cloth grinding life and the surface grinding quality of the workpiece are determined by the primer layer and the covering layer together. Along with the increasing environmental awareness, the preparation of the bio-based phenolic resin by using lignin and other bio-based resources to replace petrochemical phenolic resources has become an important research direction for realizing green low-carbon transformation of the adhesive. Lignin is a natural aromatic polymer, the molecular structure of the lignin contains a large number of phenolic hydroxyl groups, alcoholic hydroxyl groups and active sites, and the lignin has a rigid benzene ring skeleton, and the lignin is introduced into a phenolic resin system, so that the cost can be reduced, the carbon footprint can be reduced, and better rigidity and thermal stability can be provided for the resin. In the prior art, although numerous schemes of lignin modified phenolic resin are developed, the application fields of the lignin modified phenolic resin are mainly focused on the improvement of adhesives for furniture splints and artificial boards. The lignin adhesive is focused on the shear strength and the bonding capability at normal temperature, and the cured product of the lignin adhesive usually has the defects of uneven crosslinking density, low heat softening point, insufficient shear resistant elastic modulus and the like and cannot bear high-temperature friction and high-frequency impact load generated during grinding, so that the lignin adhesive is difficult to be directly applied to the field of grinding tool manufacturing. The lignin has the problems of poor compatibility, severe viscosity fluctuation in storage period, large brittleness of the adhesive layer, influence of adhesive layer inclusion particles on flatness and the like due to the fact that the lignin has large molecular weight, complex structure and low reactivity after being introduced into a phenolic resin system. When the adhesive is used as furniture adhesive, the defects are not obvious due to the inclusion of the surface of the plate and the lower dynamic stress requirement, but for the production of abrasive cloth, the particles mixed in the adhesive can directly cause uneven coating thickness and seriously affect the uniformity of subsequent sand planting. If the process of further decomposing lignin by strong acid or alkali at high temperature is adopted, although the problem of particulate inclusion can be solved, the complex process conditions and high cost can lead to complete loss of economic and environmental protection value for lignin utilization. In addition, the high-precision grinding field puts higher requirements on the performance of the abrasive cloth. The adhesive layer of the abrasive cloth needs to have extremely high thermal stability and thermal creep resistance at the same time so as to ensure that stable support of abrasive particles can be maintained at a short-time high temperature of high-speed grinding, thereby ensuring the grinding quality of a workpiece. Meanwhile, the high-precision electrostatic sand-planting process has more stringent requirements on the adhesive, firstly, the adhesive solution needs to have excellent coating rheological property and shearing recovery capability, ensures that the primer still has good wettability in a specific high-viscosity interval, realizes precise orientation and grabbing of abrasive particles through high thixotropic property at the moment of sand planting, and secondly, the adhesive needs to have proper dielectric property so as to prevent local breakdown or charge loss of an electrostatic field on the sand-planting surface, thereby ensuring precise orientation of the abrasive particles by electric field force. The adhesive prepared by the existing lignin modification process is difficult to meet the use requirement of high-precision abrasive cloth, and the application of lignin in the adhesive for the abrasive cloth is limited. Disclosure of Invention Aiming at the defects, the invention aims to provide a preparation method of a bio-based composite adhesive, an adhesive composition and abrasive cloth, and solves the problem that the adhesive meeting the use requirement of high-p