PETG blow molding film and preparation method thereof

Abstract

The invention relates to improvement of a PETG (polyethylene glycol terephthalate-1, 4-cyclohexanedimethanol ester) thin film and a preparation method. The PETG thin film is prepared by mixing 85-92 wt. % of PETG, 2.0-4.0 wt. % of opening agent, 0.5-1.5 wt. % of slipping agent, 0.2-1.0 wt. % of antistatic agent, 0.005-0.01 wt. % of chain extender and 5.0-10.0 wt. % of toughening agent blow molding, making film and shaping. Compared with casting and stretching, the invention has the advantages of short flow, convenient processing, no generation of scrap edge, high film-forming rate which can be increased by 8-10% than a stretching method, equipment investment saving, low operating cost, low production cost which can be reduced by about 20% or more and strong adaptability, adoption of various blowing measures for making the blown film, flexible and convenient product replacement and the like. Different blowing processes can be employed to obtain a non-shrinkage polyester film, and a unidirectional heat-shrinkable PETG film having approximate shrinkage rates lengthways and breadthways and giving priority to the lateral shrinkage rate. The resulting PETG thin film can be applied to a packaging film, a preservative film, a shed film, a label film and a tangle film.

Description

technical field [0001] The invention is an improvement to a PETG (polyethylene terephthalate-1,4-cyclohexanedimethanol) film and a preparation method, in particular to a blown film and a preparation method. Background technique [0002] Modified polyester PETG is synthesized by introducing 1,4-cyclohexanedimethanol monomer in the polymerization process and modifying PET by copolymerization. Compared with PET, PETG has a significantly lower crystallization rate, wider molding range, higher glass transition temperature, superior optical properties, good printability, better mechanical and processing properties, and has been applied to plates, sheets, and shrink films. , bottles, profiles and other products. Among them, heat shrinkable packaging film is one of the important uses. At present, polyethylene terephthalate-1,4-cyclohexanedimethanol (modified polyester PETG) films are basically formed by casting and stretching flat film preparation methods, that is, made of PETG an...

AI Technical Summary

Problems solved by technology

[0010] The polyester film preparation methods disclosed above are basically bidirectional or unidirectional casting and stretching flat film forming, and the shortcomings of the stretching method still exist.

[0011] The modified copolyester heat-shrinkable film disclosed in Chinese patent CN101134810 can be prepared by blown film, but it is a new copolyester modified by adding new monomers during the polymerization process, not 1,4 - Cyclohexanedimethanol modified PETG polyester, which is slightly less tough than PETG

However, the melt properties of PETG materials are different from those of general-purpose plastics. They are too sensitive to processing temperature, and their melt viscosity is greatly affected by temperature changes. When the temperature is too high, the melt strength is low, it is difficult to lift the film in the blown film, and it cannot be formed normally; when the temperature is low, the melt tends to solidify, the strength is too high, and it is difficult to inflate, which makes PETG material blown film difficult to operate and control. Ensure continuous and stable blown film production

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