Current Situation and Development Trend of Amino Molding Plastics at Home and Abroad

Amino molding compound, commonly known as tourmaline powder, is made by adding other fillers, release agents, curing agents, pigments, etc. to the amino resin matrix through a certain plasticizing process. Due to the low price of raw materials, simple production process, easy environmental protection, bright color, smooth appearance, odorless and tasteless, self extinguishing and arc resistance, heat resistance, flame retardancy, low smoke, stable product size, good electrical insulation, easy coloring and other advantages, it is widely used in electronics, electrical appliances, automobiles, machinery, household utensils and other industries (especially melamine plastics). There are many kinds of amino molding compounds, which can be divided into urea formaldehyde molding compound (UF), urea melamine formaldehyde molding compound (UMF) and melamine formaldehyde molding compound (MF) according to the resin type, and can be divided into three categories according to the filler type α- Cellulose and glass fiber are divided into two categories, namely, molding plastics and injection materials according to the processing method. Domestic production process and development As early as 1920, BASF in Germany began to study amino resin. In 1922, British BIP Company was the first to have an industrial product (BEETLE), and the amino molding compound has a history of 80 years. The United States, Japan, Western Europe and other advanced countries have gradually transferred this ancient plastic product to developing countries, especially China. Shanghai Tianshan Plastics Factory was the earliest manufacturer of amino molding plastics in China. In 1957, the former Soviet Union introduced production technology, and then gradually industrialized production. After more than 40 years of development, the process and equipment have been improved. At present, there are two production process routes of amino molding compound, one is the wet process route adopted by most countries, and the other is the BUSS method created by the Swiss BUSS company. The wet process route is: urea (melamine) and formaldehyde first generate resin in the reactor, then the filler and other auxiliary materials are mixed with the resin in the kneader, then dried in the dryer, and then crushed, ball milled and screened into finished products. The BUSS method has only two steps: urea and formaldehyde react in the reactor, and then other fillers and resins are added in the high-speed mixer. The high-speed mixing and dehydration can directly produce granular products. These two processes are quite mature, but the first route is the main one. At present, the domestic production equipment is gradually close to that of foreign countries. The dryer has developed from the original box oven to the current mesh belt oven with high automation, large output and easy control. The pulverizer has also developed from hammer type to water-cooled high-speed universal pulverizer. The ball mill has imitated the foreign water-cooled type. The lining wall has been changed from the original 10cm to 3-4cm porcelain lining. The arrangement of the ball mill also has two ways, parallel and series, which greatly improves the output and reduces the labor intensity of workers. In order to shorten the time from the resin to the kneader, the resin storage tank has been reduced. The capacity of the kneader has been changed from 500dm3 to 1500dm3, so that all the resins in each reactor are just put into the kneader of 1500dm3, and the resins used are kept fresh. The degree of polymerization is 1-3, and the molecular weight is only 20-30, which is conducive to the impregnation of pulp and the reaction of hydroxymethyl group in pulp and resin. At present, the output of one production line has increased from 2kt to 4kt. The dust removal and ventilation in the workshop have been greatly improved, so that the dust and waste gas in the workshop can meet the environmental requirements. 1) Formula improvement. At present, there are more than 40 manufacturers of amino molding compounds in China, with almost the same formula. They originated from the former Soviet Union 40 years ago, and no major innovation was made by any enterprise. Therefore, the technical level, quality and performance of the products are almost the same, although they all meet certain standards, they are all low standards, especially the appearance (smoothness and brightness) is quite different from the advanced foreign level. The direct performance is that the appearance of our products is not bright and bright, and the price of products is low. In addition, the filler mass fraction of molding plastics produced by us is low (about 25%), so the strength is low, which is easy to cause cracking or damage of the parts. In particular, the mahjong tiles produced are easy to be damaged. Of course, low filler content is easy to master in production, and liquidity is not easy to lose. 2) Improvement of equipment. We now produce equipment that is more imitated than independently designed. The equipment performance, efficiency and service life are relatively poor. In particular, automation control needs to be improved. For example, the air volume and steam of the dryer are controlled manually, while the foreign advanced dryer has achieved full automation, and the drying temperature is constant at 80 ℃, so the product quality can be guaranteed, especially the fluidity. Because the quality of pigments in China is not stable, and the dry dyeing is not very successful, the box dryer (commonly known as the soil oven) with manual material turnover is still needed to produce color powder. The basic form and principle of the soil oven in China are the same as they were decades ago. In a word, there are still many deficiencies in the process and equipment of amino molding compounds in China, and continuous innovation is needed to improve the technical level of amino molding compounds.