Sealing temperature

Materials are also blended with VDC copolymers to improve toughness (211—214). VinyHdene chloride copolymer blended with ethylene—vinyl acetate copolymers improves toughness and lowers heat-seal temperatures (215,216). Adhesion of a VDC copolymer coating to polyester can be achieved by blending the copolymer with a linear polyester resin (217). 

Polyester (Textured or Filament) Dyed Under Pressure. The dyebath (50°C) is set with water conditioning chemicals as required, acetic acid to ca 5 pH, properly prepared disperse dyes, and 1—3 g carrier/L. The bath is mn for 10 minutes, then the temperature is raised at 2°C/min to 88°C and the equipment is sealed. Temperature is raised at l°C/min to 130°C, and the maximum temperature held for 1/2—1 h according to the fabric and depth of shade required. Cooling to 82°C is done at 1—2°C/min, the machine is depressurized, and the color sampled. The shade is corrected if needed. Slow cooling avoids shocking and setting creases into the fabric. Afterscour is done as needed. 

The lower melting point can be advantageous in that film sealing temperatures may be lower thus allowing faster production rates of packaging products. 

All liquids used for filling must flow by gravity at a temperature of 35°C or less. The sealing temperature of gelatin films is 37 40° C. 

Films and sheets with high clarity, puncture resistance, impact strength, low heat-seal temperature used for shrink-wrap, heavy-duty shipping sacks, produce bags, bag-in-box food and technical packaging films... 

The continuous use temperatures in an unstressed state are generally estimated from 90°C for LDPE up to 110-120°C for HDPE and 130°C for crosslinked polyethylenes if the softening or melting temperatures are higher. For example, the sealing temperature of a given grade of VLDPE is 83°C. 

A344 Seal temperature indicator SEAL TI c 1 1 ryes (true) Or no ( Ise)... 

During the pouching process, operators should perform routine monitoring of heat seal temperature, heat seal dwell time, and heat seal pressure, and at the same time check the integrity of the sealant layers. It is recommended that... 

Pouching Poor pouch seal. Adjust heat sealing temperature Adjust heat sealing pressure Adjust heat sealing dwell time... 

The combination of flexibility, clarity and tensile set and low heat seal temperatures (Table 18) enables syndiotactic polypropenes to be applied instead of PVC, EVA and LLDPE in films, foils and extruder products. 

Glass Transition Temperature, C 3+-3 Film Formation at Room Temperature Yes Tensile Strength, psi 600 Elongation at Break, % 1700 Heat-Sealing Temperature, F 190... 

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