The thermoplastic acrylic resin does not undergo further cross-linking during the film formation process, so it has a relatively large molecular weight, has good gloss and color retention, water and chemical resistance, fast drying, easy construction, easy to recoat and rework, and preparation The aluminum powder has good whiteness and positioning when it is painted. Thermoplastic acrylic resin is widely used in automotive, electrical appliances, machinery, construction and other fields.
Thermosetting acrylic resin means that it has certain functional groups in the structure, and it forms a network structure by reacting with the functional groups in the added amino resin, epoxy resin, polyurethane, etc. during the production of paint. Thermosetting resins generally have a relatively low molecular weight. Thermosetting acrylic coatings have excellent fullness, gloss, hardness, solvent resistance, weather resistance, do not change color and do not return to yellow when baked at high temperature. The most important application is to make amino-acrylic paint with amino resin, which is widely used in automobiles, motorcycles, bicycles, coiled steel and other products.
According to the production method, it can be divided into:
1. Emulsion polymerization is made by reacting and polymerizing monomer, initiator and distilled water together. Generally, the resin formed is an emulsion with a solid content of 50%, which is an emulsion solution containing about 50% water. The synthesized emulsion is generally milky white bluish (tindal phenomenon), and the glass transition temperature is designed according to the FOX formula. Therefore, the molecular weight of this type of emulsion is large, but the solid content is generally 40% -50%. The production industry requires precise control, due to the use of water as a solvent, environmentally friendly emulsion.
2. Suspension polymerization is a relatively complicated production process, which is a method adopted for the production of solid resin. Solid acrylic resin, using acrylic acid ester with methyl down-reaction polymerization. Acrylates with methyl groups generally have certain functional groups, and their polymerization reaction in the reaction kettle is not easy to control, and it is easy to be sticky and burst into the pot. The process is to put the monomer, initiator and auxiliary into the reactor and then put in distilled water to react. After reacting for a certain time and temperature, wash with water, then dry, filter, etc. The production control of its products is relatively strict. If the link in the middle is not done properly, the products it produces will have a certain impact. Mainly reflected in the difference in color and molecular weight.
3. Bulk polymerization is a highly efficient production process. The process is to put the raw materials into a special plastic film, and then react into agglomerate, take out and crush, and then filter. The solid acrylic resin produced by this method has the highest purity among all production methods, and the product is stable Sex is also the best, and its shortcomings are also full. Acrylic resins made by bulk polymerization are not very soluble in solvents. Sometimes the same monomer and the same ratio are difficult to dissolve several times by suspension polymerization, and the dispersibility of the pigment is not as good as suspension polymerization acrylic resins.
4. Other polymerization methods Solvent method reaction, the solvent is used as an intermediary substance during the reaction, and the solvent is removed after the reaction kettle is completed.
The role and use of acrylic acid
Important organic synthetic raw materials and synthetic resin monomers are vinyl monomers with a very fast polymerization rate. Most are used to make acrylic esters such as methyl acrylate, ethyl ester, butyl ester, hydroxyethyl ester. Acrylic acid and acrylic acid ester can be homopolymerized and copolymerized, and can also be copolymerized with monomers such as acrylonitrile, styrene, butadiene, vinyl chloride and maleic anhydride. Its polymers are used in industrial sectors such as synthetic resins, adhesives, synthetic rubbers, synthetic fibers, superabsorbent resins, pharmaceuticals, leather, textiles, chemical fibers, building materials, water treatment, oil mining, and coatings. Acrylic acid is one of the important raw materials for water-soluble polymers. Graft copolymerization with starch can produce super strong water-absorbing agent; preparation of acrylic resin, rubber synthesis, coating preparation, pharmaceutical industry;
Main application areas:
(1) Size on warp
The warp yarn sizing agent prepared from acrylic, methyl acrylate, ethyl acrylate, acrylonitrile, ammonium polyacrylate and other raw materials is desizing less than the polyvinyl alcohol upper sizing agent, saving starch.
Using acrylic, methyl acrylate, ethyl acrylate, 2-ethylhexyl acrylate and other copolymer latex, it can be used as an adhesive for electrostatic flocking and hair planting.
(3) Water thickening
a Use acrylic acid and ethyl acrylate copolymer to make high molecular weight powder. It can be used as a thickener for oil fields. It can increase 500t of crude oil per ton of product, which has a good effect on old wells
b Adhesives used acrylic acid, methyl acrylate, ethyl acrylate, 2-ethylhexyl acrylate, etc .;
(4) Coated paper coating agent
Use acrylic, butyl acrylate, 2-ethylhexyl acrylate, styrene and other quaternary copolymer latex as the coating for coated paper. The color is not yellowed, the printing performance is good, the roller is not sticky, and it is better than styrene-butadiene latex to save drying. Kusu
Using acrylic acid can produce various polyacrylate products (such as ammonium salt, sodium salt, potassium salt, aluminum salt, nickel salt, etc.). Used as coagulant, water treatment agent, dispersant, thickener, food preservative, acid and alkali resistant desiccant, softener and other polymer additives