Two-way stretch polylactic acid film capable of being directly thermally sealed and preparation method of two-way stretch polylactic acid film

A technology of biaxial stretching and polylactic acid, which is applied in the direction of chemical instruments and methods, lamination, layered products, etc., can solve the problems of low tensile strength, brittle characteristics of PLA materials, and low transparency, so as to improve tensile strength and Uniformity of thickness, reduction of intermolecular stress, and widening of the application field

Active Publication Date: 2015-05-13
SHANDONG SHENGHE PLASTIC DEV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] Although PLA has obvious advantages, its use and development are limited due to its low heat resistance temperature (softening point 55°C).
At present, most PLA film preparation processes adopt blow molding to form films. This film forming process has problems such as uneven film thickness, low transparency, and low tensile strength. However, how to improve the temperature resistance of PLA films has not been systematically studied and reported.
[0005] Especially in the research process of PLA biaxial stretching, there are many technical barriers, resulting in the fact that biaxially stretched PLA film (abbreviated as BOPLA) has not been industrialized.
[0006] First of all: there is no professional BOPLA production line at home and abroad, and there is no effective production plan for the BOPLA production stretching process and stretching conditions
[0007] Second: Heat-sealable BOPLA has not yet been produced
[0008] Third: The PLA material is brittle and cannot penetrate the film effectively after forming a cast sheet
[0009] Fourth: Since there is no professional PLA production line, the PLA experimental production line is carried out on the BOPET production line. Due to the large melting point difference between PET and PLA, PLA and PET cannot be converted efficiently
[0010] Many of the above technical problems have led to the unsuccessful industrialization of the biaxially stretched film of polylactic acid, thus limiting the further development and application of polylactic acid film

Method used

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  • Two-way stretch polylactic acid film capable of being directly thermally sealed and preparation method of two-way stretch polylactic acid film
  • Two-way stretch polylactic acid film capable of being directly thermally sealed and preparation method of two-way stretch polylactic acid film

Examples

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Embodiment 1

[0042] A biaxially stretched polylactic acid film that can be directly heat-sealed, including ABC three-layer structure arranged in sequence, wherein layer A is the surface heat-sealing layer, and the raw material of the layer A is heat-sealable PLA chips; layer B is the middle core Layer, the raw material of the B layer is crystalline PLA slices; the C layer is an anti-blocking layer, and the raw materials of the C layer are 45wt% crystalline PLA slices and 55wt% PLA anti-blocking agent masterbatch slices.

Embodiment 2

[0044] A biaxially stretched polylactic acid film that can be directly heat-sealed, including ABC three-layer structure arranged in sequence, wherein layer A is the surface heat-sealing layer, and the raw materials of the layer A are 85wt% crystalline PLA slices and 15wt% non- A heat-sealed PLA slice composed of crystalline PLA slices; B layer is the middle core layer, and the raw material of the B layer is a crystalline PLA slice composed of 98wt% crystalline PLA slices and 2wt% amorphous PLA slices; C layer is an anti- Adhesion layer, the raw materials of the C layer are 50wt% crystalline PLA slices and 50wt% PLA anti-blocking agent masterbatch slices, and the PLA anti-blocking agent masterbatch slices are crystalline PLA containing 5wt% anti-blocking agent slice.

Embodiment 3

[0046] A biaxially stretched polylactic acid film that can be directly heat-sealed, including ABC three-layer structure arranged in sequence, wherein layer A is a surface heat-sealing layer, and the thickness of layer A accounts for 15% of the thickness of the film. The raw material of layer A is It is a heat-sealed PLA slice composed of 90wt% crystalline PLA slices and 10wt% non-crystalline PLA slices; B layer is the middle core layer, and the thickness of B layer accounts for 70% of the thickness of the film, and the raw material of the B layer is 99wt % crystalline PLA slices and 1wt% non-crystalline PLA slices; the C layer is an anti-adhesion layer, and the thickness of the C layer accounts for 15% of the thickness of the film, and the raw material of the C layer is 60wt% crystalline Type PLA slices and 40wt% PLA anti-blocking agent masterbatch slices, the PLA anti-blocking agent masterbatch slices are crystalline PLA slices containing 6wt% anti-blocking agent, and the anti...

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Abstract

The invention discloses a two-way stretch polylactic acid film capable of being directly thermally sealed and a preparation method of the two-way stretch polylactic acid film. The two-way stretch polylactic acid film comprises an A layer, a B layer and a C layer, which are sequentially arranged, wherein the A layer is a surface layer heat-seal layer, the B layer is a middle core layer, the C layer is an anti-adhesion layer. The preparation method comprises the steps of melting and extruding raw material sections of the layer A, the layer B and the layer C respectively at the temperature of 180 to 220 DEG C by virtue of a double-screw extruder, placing fused mass in a three-layer co-extrusion die head, casting the fused mass to form PLA sheets, preheating the PLA sheets, carrying out longitudinal stretch and cooling stereotyping on the PLA sheets, re-preheating the PLA sheets after the longitudinal stretch and cooling stereotyping, then transversely stretching the PLA sheets, carrying out stereotyping crystallization and cooling stereotyping on the PLA sheets, carrying out the pulling sectioning and corona treatment on the PLA sheets, and carrying out the coiling to prepare the two-way stretch polylactic acid film capable of being directly thermally sealed with thickness of 20 to 100 micrometers. The two-way stretch polylactic acid film capable of being directly thermally sealed can be directly produced on a BOPET production line, the prepared film can be directly thermally sealed, and the application range of the polylactic acid film can be enlarged.

Description

technical field [0001] The invention relates to the technical field of polylactic acid films, in particular to a biaxially stretched polylactic acid film that can be directly heat-sealed. Background technique [0002] Since the invention of plastic packaging products, it has played an important role in human life and production. With the extensive use of plastic packaging, it has brought a devastating environmental disaster to the living environment of human beings, resulting in serious "white pollution" and so on. question. [0003] Polylactic acid (PLA) is the most important biodegradable and environmentally friendly polymer material among aliphatic polyesters. Its monomer raw material lactic acid can be produced on a large scale by fermenting corn and other food crops, so It can completely get rid of the dependence of ordinary films such as polystyrene, polypropylene, and polyvinyl chloride on petroleum resources; PLA materials have excellent biodegradability. In the nat...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B32B27/06B32B27/18B32B27/36B32B37/02B32B38/18
CPCB32B27/06B32B27/18B32B27/36B32B37/02B32B38/18
Inventor 王凯贺海峰冯益强
Owner SHANDONG SHENGHE PLASTIC DEV
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