Abstract: In this paper, monomer-grafted epoxy resin was used to prepare waterborne epoxy resin. The molecular structure, curing process and mechanical properties were studied, and the best formulation and preparation process for the synthesis and curing of waterborne epoxy resin were determined. The research results show that the self-made waterborne epoxy resin using triethanolamine and diethylenetriamine has a good curing effect, in which the bonding strength of triethanolamine ≥8.6Mpa, the curing effect is good. The non-woven polishing abrasive made of water-based epoxy resin is suitable for polishing floor tiles, knives and other materials. The water-based epoxy resin in the abrasive is firmly bonded, evenly distributed, and there is no obvious agglomeration; the surface of the polished tool material is scratched The marks are uniform, with good surface finish and brightness.
1 Introduction
Abrasive tools made of non-woven material as a matrix are a new type of elastic grinding tools developed in recent years. It is not only highly efficient and wear-resistant, easy to use, less dust and no pollution, high porosity and not easy to burn the workpiece. Characteristics, and because of its own elastic skeleton, it can be used for the processing of more complex shapes and curved surfaces. It can be widely used for derusting, roughing, fine grinding and polishing of various industrial sectors, and is a promising elastic grinding tool.
At present, most of the non-woven abrasive tools on the market use bisphenol A epoxy resin as the adhesive, which is a viscous liquid or solid, insoluble in water, soluble in organic solvents such as aromatic hydrocarbons and ketones. Volatile, flammable, explosive, and toxic. With the increasingly urgent and strict requirements for environmental protection, the application of traditional epoxy resins has been greatly restricted. The so-called waterborne epoxy resin refers to a stable dispersion system prepared by dispersing the epoxy resin in the form of particles or droplets in a dispersion medium using water as the continuous phase through physical or chemical methods.
The water-emulsion system studied in this paper is a translucent to milky white emulsion system in which epoxy resin is dispersed in water in the form of droplets under the action of an emulsifier. The surface of the droplet is an emulsifier molecule with a hydrophilic group, and the interior of the droplet is a hydrophobic epoxy molecule.
2 Experimental part
2.1 Raw materials
E-44 epoxy resin, Lanxing New Material Wuxi Resin Factory
Benzoyl peroxide, Tianjin Kemeiou Chemical Reagent Co., Ltd.
Non-woven fabric, curing agent, emulsifier, etc.
2.2 Synthesis of waterborne epoxy resin
Take 60g of E-44 epoxy resin and pre-dissolve it with 40ml of n-butanol, and add it to a three-necked flask equipped with a stirrer, condenser and thermometer. Then add 0.9g (1.5% of the total amount of epoxy resin) benzoyl peroxide (BPO) solution dissolved in acetone, and at the same time raise the temperature of the system to 90 ° C within 10-20 minutes, and slowly add 6g (epoxy (10% of total resin) Grafted monomers were added dropwise within 30 to 60 minutes, and the temperature was raised to 100 ° C and the reaction was carried out at a constant temperature for 3 hours. After the system temperature is cooled to 50 ° C, about 10 ml of emulsifier is added under high-speed stirring to adjust the system pH to 7-8. Stir at a constant temperature of 50 ° C for 1h, add about 30ml of water, and keep for half an hour to prepare a waterborne epoxy resin system.
2.3 Preparation of non-woven abrasive tools
The prepared water-based epoxy resin and brown corundum, ethanol, polishing agent, leveling agent, etc. are mixed in a certain ratio, and then formed according to the order of pulping-rubbing-rolling-lamination-solidification-shape processing.
3 Results and discussion
3.1 Infrared spectrum analysis
The graft reaction type is to introduce hydrophilic groups into the epoxy resin by graft copolymerization. Generally, the epoxy resin is dissolved in a solvent, and then an appropriate amount of carboxyl-containing monomer and initiator are added to heat the reaction to make the epoxy resin molecule. The methylene-CH2- or -CH- in the compound becomes the active point to initiate the polymerization of the monomers to generate a modified epoxy resin containing carboxyl groups, which is neutralized by adding ammonia and water, and then adding water to prepare a water-based epoxy resin. By grafting method, a modified epoxy resin with epoxy groups and hydrophilic groups in the molecule was synthesized, and its structure was characterized by infrared spectroscopy.
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