-
Categories
-
Pharmaceutical Intermediates
-
Active Pharmaceutical Ingredients
-
Food Additives
- Industrial Coatings
- Agrochemicals
- Dyes and Pigments
- Surfactant
- Flavors and Fragrances
- Chemical Reagents
- Catalyst and Auxiliary
- Natural Products
- Inorganic Chemistry
-
Organic Chemistry
-
Biochemical Engineering
- Analytical Chemistry
- Cosmetic Ingredient
-
Pharmaceutical Intermediates
Promotion
ECHEMI Mall
Wholesale
Weekly Price
Exhibition
News
-
Trade Service
China Coatings Online News
Huang Yuanwen 1 Wang Yiying 2 Wang Bin 1 Li Yajie 1 (1 Chinese Academy of Sciences Guangzhou Chemical Co., Ltd.; 2 Zhanjiang Normal College Interns)
Abstract: This article with small molecular polyether-type epoxy resin and acetaldehyde as active thinners, with adipamine as curing agent The effects of additives such as epoxy resin content, silane concedants, ambient temperature and paint accumulation heat on the curing of modified epoxy coatings were studied, a fast-solid type of low-start viscosity high permeability modified epoxy coating was prepared, and its application in the mold material of porous absorbent resin for high-pressure injection of ceramic sanitary ware was discussed.Keywords: rapid curing; high penetration
porous absorbent resin mold
high-pressure injection slurry in the United States, Germany, Japan, Italy and other developed countries have been widely used, they have obtained huge economic and social benefits, especially in Japan, high-pressure molding accounted for a large proportion, with it can form almost all sanitary ware products. One of the keys to the popularization and application of high-pressure slurry technology is the localization of plastic molds. Plastic mold has a high service life, reuse more than 10000 times, is the domestic ceramic molding mold materials in recent years to develop the direction.resistance, water resistance, acid-base corrosion resistance, temperature resistance and compression strength, bending strength and other physical and mechanical properties of plastic molds are significantly better than gypsum molds. Absorbent resin mold material is an open-type micro-hole material, in the use of high-strength absorbent resin plastic mold, it is usually necessary to directly close some mold surfaces in order to achieve directional absorption of water. High pressure injection pressure, pressure up to 30 to 40 atmospheric pressure, fast-solid type high permeability modified epoxy coating can meet this requirement.epoxy resin is a kind of adhesive material with excellent mechanical performance, corrosion resistance and bonding performance and chemical stability, but the commonly used bisphenol A epoxy resin viscosity, poor mobility, slow low temperature curing, improving its mobility and rapid curing performance is a major application in the field of modified epoxy resin, especially in the field of coatings, especially in the winter when the temperature is low, the ordinary modified epoxy thin layer coating is far from meeting the needs of modern rapid curing engineering. The low viscosity of diluents is one of the most commonly used ways to improve mobility. Based on many years of research and application, this paper studies a rapidly curing high-permeability modified epoxy coating with small molecule polyether-type epoxy resin and acetone as active thinners, and discusses its application in the mold material of porous absorbent resin for high-pressure injection of ceramic sanitary ware.1. Experimental part
1.1 material
622 small molecule polyether epoxy resin, E-51 epoxy resin, E-44 epoxy resin, acetalehyde, acetone, II Ethylene triamide (DETA), triethylene teetamine (TETA), N-amino ethyl pyridoe (AEP), modifiers, silane coupled agents, promoters, etc. are commercially available industrial products, porous absorbent resin mold materials (homemade).1.2 preparation method (see Figure 1)
Figure 1 preparation of highly permeable modified epoxy protective coating
1.3 strength test and table dry performance
2. Results and discussion of the curing reaction of
2.1 active thinners (see Figure 2)
Figure 2 Curing reaction of active thinners
small molecule polyether type 622 epoxy resin active thinner viscosity is lower, acetaldehyde, acetone viscosity is lower, the mixture is only 0.69mPa.s, well below the viscosity of water 1mPa.s, with high permeability. In this system, the base group in the active thinner has catalytic alcohol aldehyde contraction reaction, and further dehydration and amine addition reaction, gradually forming gels and polymers, with a certain strength. The amine silane coupling agent reacts further with the water generated by the dehydration reaction to produce ethanol, which promotes the aldehyde shrinkage reaction, which makes the contraction reaction more complete and stronger. The active hydrogen in polyamines also reacts with 622 epoxy resins to form stronger polymers.reaction activity of 2.2 amine curing agents
different structures of amine molecules and epoxy resin reaction activity is not the same, mainly depends on the alkaline and spatial resistance of N atoms. Aromatic amines had the lowest activity, followed by lipocamine, and fatty amines were the most active. Therefore, adipose polyamine is the preferred curing agent for fast curing systems, such as ethylene triamide and triethylene tetamine. N-aminocethyl pyridoe AEP is a polyamine in the mixing system of fatamine and lipocycline, which has both advantages and moderate curing speed.fatty amine curing agent is the most commonly used curing agent of epoxy resin, in which the active hydrogen makes bisphenol A epoxy resin E-51, E-44 open-loop polymerization reaction. The first hydrogen space bit resistance in beamine is small, the reaction activity is large, and epoxy resin quickly opens the ring reaction, and releases a lot of heat, the heat released accelerates the reaction to form a three-dimensional network solidified body.the amine-curing heating effect ofepoxy resin makes the drying time of the mixture in a thin coating manner significantly different from that of the pouring body, especially when it contains the volatile active thinner acetone, which shows different drying speeds at different temperatures.2.3 Paint starting viscosity and solidification strength
This experiment used the 100gA part at room temperature as an example, the dosage of different curing agents, its curing time and strength results can be seen in Table 1.
the curing properties of the coating at table 1 at room temperature of 20As can be seen from Table 1, the viscosity of the adhesive without epoxy resin is very small after mixing, after a certain period of time can also be gelding into a certain strength of solidified body, coating film table drying time of up to 3d. With the increase of epoxy resin, the initial viscosity increases, the curing accelerates, the coating surface drying time is shortened, and the later strength increases. On the other hand, with the increase of curing agent dosage, curing speed up, early strength is higher, basically 1d can reach a certain strength.epoxy E-51 content reaches 15% when the viscosity is very low, 1.1mPa.s, with excellent permeability, and can also achieve a certain strength, suitable for bottom coating. When the E-51 content of epoxy resin reaches 40%, it has both low viscosity and high permeability, but also has excellent technical and film-forming properties, suitable for coating. When epoxy E-44 replaces E-51, the viscosity increases and the early strength increases slightly.2.4 Effect of temperature on curing
As mentioned earlier, the amine curing reaction of epoxy resin is a heat release reaction, and the accumulation of heat and ambient temperature have a great impact on the coating film and pouring body strength. Table 2 shows that in the room temperature of 30 degrees C environment due to the accumulation of heat, no timely cooling, pouring bodies are occurring fast and slow different bursts, but in the thin coating mode due to the contact surface large cooling good, no explosion, table dry speed is faster. With the increase of epoxy resin, the drying time of the coating is shortened and the curing accelerates.Table 2 paint curing performance at room temperature 30 degrees C
but at low temperature 12 degrees C environment, the curing speed and strength of the pouring body with the increase of epoxy resin amount and significant changes, coating table dry time also opened a great distance, from 2 days to 1 day. Table 3 shows that at low temperatures, the intensity of ab mixture in the first 1 day is shown from 0 strength of viscous liquid to 12.6MPa, after 3 days can be cured, with a certain strength.
Table 3 curing properties of the coating at room temperature of 12 degrees C
Therefore, in order to make the coating at low temperature can be quickly cured, in addition to improving the epoxy resin content, but also with the appropriate maturation process, so that AB after mixing ripe for a period of time, so that the mixture accumulates a certain amount of heat and then brush. Experiments show that the maturation time is 0.5 to 1h, when the ambient temperature is high, the maturation time is shortened and the maturation time is extended when the ambient temperature is low., in addition, infrared heating can be used to increase the ambient temperature and speed up the reaction. Especially in environments below 10 degrees C, epoxy resin fatty amine opening ring polymerization reaction is very slow, currently only through external heating to speed up the curing process.3. Application
modified epoxy coating has a high bonding strength, anti-pressure folding strength, is an ideal waterproof material, can withstand high water pressure and its impact, so it has a very practical value in ceramic high-pressure injection.
High-pressure slurry molding cycle is short, high efficiency, blank quality is good, no need to repair blanks, high strength, no drying, surface finish is high, continuous injection slurry, mechanized automation level is high, production line covers a small area, good operating environment, less environmental waste, not only can greatly improve product quality, grade and improve production efficiency, but also greatly reduce labor force, labor intensity and save labor places, reduce environmental pollution, improve the happiness index of front-line workers. high-pressure slurry molding technology in China began with the introduction of foreign technology in the early 1990s. Today, China's economy for many years continued to develop at a high speed, land resources, energy supply is completely tight, the demographic dividend has completely disappeared, labor costs have risen sharply, workers' awareness of self-protection is growing, enterprises are facing raw materials, energy prices, economic efficiency reduction, labor shortage and environmental protection pressure, many large domestic ceramic enterprises have re-turned to the use of high-pressure slurry technology. the application of high-pressure slurry technology is the localization of plastic molds. At present, there are several units in the domestic high-pressure slurry with absorbent (or permeable) resin mold. After nearly a year of scientific and technological research, we have prepared a high-strength porous absorbent resin mold, and this fast-solid type of high-permeability modified epoxy coating applied to the porous mold material. results show that when applied to high-strength absorbent resin plastic mold, only one surface coating developed by us can penetrate the micro-hole material (unstressed rinsing mold) inside 2 to 3mm, and fast curing. It can be dried in 4h under 20 degrees C, dry in 2h in 30 degrees C environment, and has high strength, good toughness and resistance to high pressure shock. For dry mold materials that rinse pores under pressure, fast-solid, high-permeable modified epoxy coatings can penetrate almost completely into the micropores inside the mold. In addition, the fast-solid high-permeability modified epoxy coatings developed by us can meet the needs of fast-curing underground waterproofing projects at room temperatures above 30 degrees C, 20 to 30 degrees C, and 10 to 20 degrees C, but the curing is slow below 10 degrees C and needs to be further improved. The
, etc. Permeable modified epoxy grouting material .
Zhang Bin, etc. Application of solvent-free epoxy coatings in the petrochemical industry, Shanghai Coatings, 2008, (8): 139.
Huang Yuwen, etc. Silicone modified niobium-based epoxy composite material . . . China, 200510034030.5, 2006-10-18.
。