The curing temperatures of the various curing agents vary, and the heat resistance of the cured materials also varies greatly. In general, a cured product excellent in heat resistance can be obtained by using a curing agent having a high curing temperature. For the addition polymerization type curing agent, the curing temperature and heat resistance are increased in the following order:
The heat resistance of the catalytic addition-type curing agent is generally at the aromatic polyamine level. The anionic polymerization type (tertiary amine and imidazolium antimony) and the cationic polymerization type (BF3 complex) have substantially the same heat resistance, mainly because the initial reaction mechanism is different, but eventually the ether-bonded network is formed. structure.
The curing reaction is a chemical reaction, which is greatly affected by the curing temperature. The temperature increases, the reaction speed increases, and the gel time becomes shorter. The logarithm of the gel time generally decreases linearly with the curing temperature. However, if the curing temperature is too high, the performance of the cured product is often lowered, so there is an upper limit of the curing temperature; a temperature at which the curing speed and the cured product performance are compromised must be selected as a suitable curing temperature. According to the curing temperature, the curing agent can be divided into four categories: the curing temperature of the low temperature curing agent is below room temperature; the curing temperature of the curing agent at room temperature is room temperature to 50 ° C; the curing temperature of the medium temperature curing agent is 50 to 100 ° C; the curing temperature of the high temperature curing agent is above 100 ° C. .
There are few types of curing agents which are low-temperature curing type, such as polydecyl alcohol type and polyisocyanate type; in recent years, T-31 modified amines and YH-82 modified amines which have been developed and put into operation in China can be cured at 0 ° C or lower. There are many types of room temperature curing types: aliphatic polyamines, alicyclic polyamines, low molecular polyamides, and modified aromatic amines. The intermediate temperature curing type includes a part of an alicyclic polyamine, a tertiary amine, a carbazole, and a boron trifluoride complex. Examples of the high-temperature curing agent include aromatic polyamines, acid anhydrides, resole phenol resins, amino resins, dicyandiamide, and hydrazides.
For high-temperature curing systems, the curing temperature is generally divided into two stages. It is cured at a low temperature before the gel. After reaching the gel state or slightly higher than the gel state, it is post-cure after high-temperature heating. The previous stage is cured to pre-cure.
Simple installation, different lamps can be equipped, and the number of lamps can be increased or decreased freely. When there is no limit to the number of lamps installed on the track, it can theoretically not exceed the wattage of the transformer power supply.
Magnetic Spot Light,Magnetic Light Track,Magnetic Pendant Light,Led Magnetic Track Light
JINGYING , https://www.jingyinglight.com