Introduction, application, characteristics of pbt plastic

Introduction:

PBT plastic refers to a type of plastic mainly composed of polybutylene terephthalate

Polybutylene terephthalate, also known as polytetramethylene terephthalate. Referred to as PBT. It is a polycondensate of terephthalic acid and 1,4-butanediol. PBT and PET together are known as thermoplastic polyesters.

characteristic

a. Mechanical properties: high strength, fatigue resistance, dimensional stability, and small creep (very little change under high temperature conditions);

b. Heat aging resistance: the enhanced UL temperature index reaches 120~140 ℃ (outdoor long-term aging is also very good);

c. Solvent resistance: no stress cracking;

d. Stability to water: PBT is not easy to decompose in contact with water;

e. Electrical performance:

1. Insulation performance: excellent (wet and high temperature can maintain stable electrical performance, it is an ideal material for manufacturing electronic and electrical parts);

2. Dielectric coefficient: 3.0-3.2;

3. Arc resistance: 120s

f. Molding processability: injection molding or extrusion molding with ordinary equipment. Due to the fast crystallization speed and good fluidity, the mold temperature is also lower than other engineering plastics. When processing thin-walled parts, it only takes a few seconds, and it only takes 40-60s for large parts.

2. Application of PBT (usually refers to modified varieties);

a. Electronic appliances: connectors, switch parts, household appliances, accessory parts, small electric covers or (heat resistance, flame resistance, electrical insulation, molding processability);

b. Car:

1. External parts: mainly include corner grids, engine heat release escutcheons, etc.;

2. Internal parts: mainly endoscope stay, wiper bracket and control system valve;

3. Automotive electrical parts: automotive ignition coil twisted tubes and various electrical connectors, etc.

(The number of PBT used in automobiles is not as good as that of nylon, polycarbon and polyoxymethylene, but with the emergence of low warpage PBT, it will definitely be used in auto parts in the future.)

c. Mechanical equipment: belt drive shaft of video tape recorder, electronic computer cover, mercury lamp cover, electric iron cover, baking machine parts and a large number of gears, cams, buttons, electronic watch casings, camera parts (with heat-resistant, flame retardant requirements)

3. Bonding of PBT plastics:

According to different needs, the following adhesives can be selected:

1. TG-3200: One-component room temperature curing soft elastic shockproof adhesive, resistant to high and low temperature, but the bonding speed is slow, and the glue usually takes 1 or several days to cure.

2. TS-8602 instant adhesive can quickly bond PBT in seconds or tens of seconds, but the adhesive layer is hard and brittle and not water-resistant.

3. TE-9270 type, two-component adhesive, soft adhesive layer, suitable for large-area bonding or compounding of PBT. But the high temperature resistance performance is poor.

4. TE-9249 adhesive: two-component adhesive, high temperature resistance.

5. sili-1706: One-component room temperature vulcanizate, after curing, it is an elastomer with excellent waterproof, shockproof adhesive, high and low temperature resistance, if the thickness is 1-2mm, it will basically cure in 5-6 hours and has a certain strength. It will take at least 24 hours to fully cure. One-component, no need to mix, just smear and let stand after extrusion, no need to heat.