Introduction

TORELINA™ is a thermoplastic resin based on highly crystalline and highly heat-resistant polyphenylene sulfide (PPS), with which a reinforcement (such as glass fiber or mineral filler) and thermoplastic elastomers are blended at prescribed ratios.
In many respects, notes on injection-molding TORELINA™ are true of other crystalline thermoplastic resins, but it is necessary to pay careful attention to its properties such as high crystallinity and gas.

1. ① Fragility (considerations on design)
2. ② Welds (gate position)
3. ③ Gas (exhaust at the molding location, corrosion and abrasion countermeasures for the molding machine or the mold, mold deposits (mold contamination), gas vents, etc.)
4. ④ Viscosity increase (avoidance of abnormal residence)
5. ⑤ Deformation of molded products (particularly, unreinforced PPS resin, etc.)

Essentially, TORELINA™ is a material with a low moisture absorption, but it is recommended that it is subjected to sufficient predrying before molding to produce high-quality molded products. Representative predrying and injection molding conditions for TORELINA™ are as given below.

1. ① Predrying conditions: 130℃ (hot air or dehumidified air) × 3 to 4 hours
2. ② Cylinder temperature: 310℃ to 330℃ (resin temperature: 315℃ to 345℃)
3. ③ Mold temperature: 130℃ to 150℃
4. ④ Injection pressure: 40 to 100 MPa

For mold temperature control, a cartridge heater system provides the easiest solution. If particularly precise temperature control is required, temperature control using oil or pressurized hot water is recommended. No matter which system is adopted, a temperature controller with a sufficiently large heat capacity must be used.