Polylactic resin composition film and preparation method thereof

Abstract

The invention provides a polylactic resin composition film and a preparation method thereof, and relates to the field of plastic processing. The polylactic resin composition film comprises the following components: 100 weight parts of polylactic resin and 0.5 to 5.5 weight parts of functional filler which are blended, wherein the polylactic resin has the weight-average molecular weight of 80,000-300,000 and the molecular weight dispersibility of 1.5-2.2; and the functional filler is at least one of the following inorganic fillers: calcium carbonate, clay, silica, alumina, barium sulfate, calcium sulfate, talc, magnesium sulfate, titanium dioxide, zeolite, aluminum sulfate, kieselguhr, kaolin, calcium oxide and magnesium oxide. The preparation method comprises the following steps of: melting, blending and granulating the components in the proportion, casting and pressing, and biaxially tensioning to obtain the polylactic resin composition film. The film is completely biodegradable, has balanced rigidity and toughness, maintains the tensile strength, has the elongation at break improved by 3 to 7 times compared with the original elongation at break, and has uniform texture, high decorative property, high printing property and unidirectional tearing property.

Description

technical field [0001] The invention relates to the technical field of resin films, and more specifically, relates to a polylactic acid resin composition film and a preparation method thereof. Background technique [0002] Polylactic acid (PLA), also known as polylactide, is based on starch extracted from corn, wheat, cassava, etc. thermoplastic polyester. Polylactic acid is a completely environmentally friendly biodegradable material with good mechanical properties and biodegradability. It has a wide range of raw materials. It is easily decomposed and replaced by various microorganisms in nature or enzymes in animals and plants, and finally forms water and carbon dioxide. pollutes the environment, and thus is considered to be the most promising biodegradable polymer material. In addition, the non-toxicity of polylactic acid allows it to be used in packaging that comes into direct contact with food. In terms of post-processing, polylactic acid has excellent biodegradabili...

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Problems solved by technology

[0003] Patent CN101676324 discloses a polypropylene biaxially oriented film (BOPP) pearlescent synthetic paper masterbatch, which can be used as a packaging material for candy, ice cream, etc., but its matrix is ​​polypropylene. Although it is more environmentally friendly, its source is mostly petroleum In terms of chemical industry, the dwindling and shortage of petroleum resources is not conducive to its sustainable development

And although this method adopts the method of side feeding in order to solve the processing difficulties, the side feeding system has relatively high requirements for processing equipment

[0004] Patent CN101638509 discloses a method of filling polylactic acid with toughened calcium carbonate. Although it can play a toughening role, this method needs to be filled with a large amount of calcium carbonate. Network congestion and other problems

Moreover, the existing toughening method improves the toughness of polylactic acid and also greatly weakens its own rigidity, which is not suitable for some occasions where the film needs to be easily torn.

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