What Is Polycarbonate Resin?
Polycarbonate (PC for short) is a high molecular polymer containing carbonate groups in the molecular chain. According to the structure of the ester group, it can be divided into many types such as aliphatic, aromatic, and aliphatic-aromatic. Among them, the low mechanical properties of aliphatic and aliphatic-aromatic polycarbonates limit their applications in engineering plastics.
Polycarbonate
- Polycarbonate (PC for short) is a carbonate group
- Polycarbonate is a strong thermoplastic
- 1. With high strength and coefficient of elasticity, high impact strength, wide temperature range;
- 2. High transparency and free dyeing;
- 3 Low molding shrinkage and good dimensional stability;
- 4 Good fatigue resistance;
- 5. Good weather resistance;
- 6. Excellent electrical characteristics.
- 1. Mechanical properties: high strength, fatigue resistance, dimensional stability, and small creep (very little change under high temperature conditions);
- 2. Heat aging resistance: Enhanced UL temperature index reaches 120 ~ 140 (long-term outdoor aging resistance is also very good);
- 3 Solvent resistance: no stress cracking;
- 4 Stability to water: easy to decompose when exposed to water at high temperature (use caution in high temperature and high humidity environment);
- 5. Electrical performance:
- 6. Insulation performance: excellent (humidity, high temperature can also maintain stable electrical performance, is an ideal material for manufacturing electronic and electrical parts);
- 7. Dielectric coefficient: 3.0-3.2;
- 8. Arc resistance: 120s;
- 9. Molding processability: injection molding or extrusion of ordinary equipment.
- PC plastic bonding
- According to different needs, you can choose the following adhesives:
- 1. G-933: One-component curing soft-elastic shock-proof adhesive at room temperature, resistant to high and low temperature, curing speed of several seconds to several hours.
- 2. KD-833 instant adhesive can quickly bond PC plastic in seconds or tens of seconds, but the adhesive layer is hard and brittle, and can not withstand hot water immersion above 60 degrees.
- 3 QN-505, two-component adhesive, soft adhesive layer, suitable for large area bonding or compounding of PC plastic. But the high temperature resistance is poor.
- 4 QN-906: two-component adhesive, high temperature resistance.
- 5. G-988: One-component room temperature vulcanizate. After curing, the elastomer has excellent waterproof, shockproof adhesive, high and low temperature resistance. If the thickness is 1-2mm, it will be cured in about 10 minutes, and it will be cured in 5-6 hours. A certain intensity. It takes at least 24 hours to fully cure. Single component, no need to mix, just apply and let stand after extrusion without heating.
- 6. KD-5606: UV curing adhesive, bonding transparent PS sheet and board, can achieve no trace effect, you need to use UV light to cure. The effect is beautiful after sticking. But the high temperature resistance is poor.
- The purpose of modified PC is to toughen, improve molding processability, reduce residual deformation, increase flame retardancy, etc. The specific types of modified PC are:
- PC / ABS can improve flexural modulus, heat resistance,
- According to different needs, you can choose the following adhesives:
- 1. G-933: one-component curing soft-elastic shock-proof adhesive at room temperature, resistant to high and low temperature, bonding speed of different viscosities for several seconds to several hours.
- 2. KD-833 instant adhesive can quickly bond PC plastic in seconds or tens of seconds, but the adhesive layer is hard and brittle, and it is not resistant to hot water immersion above 60 degrees;
- 3. QN-505, two-component adhesive, soft adhesive layer, suitable for large area bonding or compounding of PC plastics. But the high temperature resistance is poor;
- 4.QN-906: two-component adhesive, high temperature resistance;
- 5.G-988: single-component room temperature adhesive, the elastomer is cured with excellent waterproof, shockproof adhesive, high and low temperature resistance, if the thickness is 1-2mm, it will be initially fixed in about 15 minutes, basically 5-6 hours Cured with some strength. It takes at least 24 hours to fully cure. Single component, no need to mix, just apply after extruding, no need to heat [2]
Problems with polycarbonate molding process
- Causes and solutions
- 1.Silver wire
- a. Moisture of raw materials Dry raw materials
- b. Resin decomposition due to overheating Reduce molding temperature
- c. The screw compression ratio is small, and the back pressure is insufficient --- increasing the back pressure
- d, mold temperature is too low-heating mold
- e. Poor exhaust opening exhaust groove on mold parting surface
- Bubbles
- a. Moisture of raw materials Dry raw materials
- b. Poor venting Improve the mold design
- 3, resin discoloration, black spots
- a. Accumulation of barrels and nozzles Cleaning barrels and nozzles
- b, the molding temperature is too high ---- reduce the molding temperature
- 4.The product is not full
- a, the plasticization of the material is not enough --- increasing the barrel temperature
- b, the mold temperature is too low ----increase the mold temperature
- c. Nozzle overflow-adjust the position of the mold
- d Injection pressure is too low Increase injection pressure
- e. Too little feeding amount Adjust feeding amount
- 5, shrink vacuum bubble
- a. Insufficient holding pressure Extend the holding time
- b, mold temperature is too low ----increase the mold temperature
- c. Injection pressure is too low Increase injection pressure
- d. The mold design is unreasonable --- increasing the runner and gate size
- e. The molding temperature is lower increasing the barrel temperature
- 6.Transparency is reduced
- a. Moisture of raw materials Dry raw materials
- b, the mold temperature is too low ----increase the mold temperature
- c. Overheating decomposition of materials Reduce molding temperature
- 7, welding marks
- a. The mold design is unreasonable Using ring gate and multi-point gate
- b, the mold temperature is too low ----increase the mold temperature
- c. Too much release agent reduce the amount of release agent
- d, the molding temperature is lower --- increasing the barrel temperature
- 8. Product cracking
- a, mold temperature is too low --- increase the mold temperature
- b, the molding temperature is lower increasing the barrel temperature
- c, the relative molecular weight of the material is too small --- reselect the material
- d. During the molding process, the relative molecular weight has decreased too much. Strict drying and shortening the molding cycle.
- e Forcibly demoulding Increase the cavity slope and improve the mold structure
- 9, difficult to demold
- a Insufficient cooling in the mold Reduce the molding temperature and extend the molding cycle
- b. Cavity slope is too small increasing cavity slope
- c. Poor ejection device Improved ejection device
- d. Rough surface of the mold trim the mold and use mold release agent
- 10.Warping
- a Insufficient cooling in the mold Reduce the molding temperature and extend the molding cycle
- b The temperature difference between male and female molds is larger Reduce the temperature difference between male and female molds
- c. Gate location and size are unreasonable Improve gate structure
- 11.Overflow
- a Injection pressure is too high Reduce injection pressure
- b, the molding temperature is too high ---- reduce the barrel temperature
- c. Insufficient clamping force Improve clamping force
- d. Insufficient mold processing accuracy Improve mold processing accuracy
Polycarbonate safety dispute
- Due to the need to add bisphenol A in the manufacture of polycarbonate, and bisphenol A as a chemical raw material, it was officially recognized as a toxic substance by the Canadian federal government on April 18, 2008, and it is strictly prohibited to add it in food packaging. The safety of carbonates is a noteworthy issue. The European Union believes that bisphenol A-containing bottles will induce precocious puberty. From March 2, 2011, baby bottles containing the chemical bisphenol A (BPA) are banned. The Ministry of Health of China and other departments issued a statement saying that from September 1, 2011, the import and sale of polycarbonate baby bottles and other baby bottles containing bisphenol A should be recalled by the manufacturer or importer.
Polycarbonate packaging and transportation
- Polycarbonate (PC) products are generally packed in ordinary woven bags, stored in a dry place, and stored and transported as ordinary items.
Storage and transportation conditions of polycarbonate
- Sealed, cool, ventilated and dry place, and stored flat.
- Low temperature injection molding PC plastic for IMD / IML process
- Mainly solve the following problems: 1. Washing 2. Poor fluidity 3. Yellowing of the product 4. Poor compatibility with the sheet and other related issues Low temperature injection PC product features: 1. Ultra-high toughness of the product 2. High transparency of the product , Super high fluidity 4, good chemical resistance 5, good compatibility with sheet
- Injection temperature: Low temperature injection molding PC plastic type A injection temperature of 220 to 240 ; low temperature injection molding PC plastic type B injection temperature of 230 to 260 .
- The following is a class A physical property table of low temperature injection molding PC plastic for IMD / IML process;
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