Degradable heat sealing film for compounding and preparation method thereof

Abstract

The invention discloses a degradable heat sealing film for compounding and a preparation method thereof. The degradable heat sealing film comprises a heat sealing layer, a middle layer and an outer layer, which are connected in sequence. The middle layer comprises the following components in parts by weight: 35 to 45 parts of PBAT, 35 to 45 parts of PLA, and 15 to 25 parts of a biodegradable nucleating agent; the heat sealing layer comprises the following components in parts by weight: 80 to 90 parts of PBAT and 10 to 20 parts of a biodegradable nucleating agent; and the outer layer comprisesthe following components in parts by weight: 80-90 parts of PBAT and 10-20 parts of a biodegradable nucleating agent. The degradable heat sealing film has the advantages that the crystallization rateof an extruded material is high, the melt strength is high, the film is not easy to break under traction, the film is easy to form, the heat sealing property is good, the printing effect is good, thehardness is moderate, certain softness and certain stiffness can be considered, and the degradable heat sealing film can be compounded with a printed film to be used as a heat-sealing layer and can beindependently made into bags.

Description

technical field [0001] The invention relates to the technical field of polymer materials, more specifically, it relates to a composite degradable heat-sealing film and a preparation method thereof. Background technique [0002] At present, with the continuous development of the national economy, the consumption of plastic products is increasing, and synthetic plastics are playing an increasingly important role in production and life. However, most of the plastic products cannot be degraded after they are discarded, and the continuous accumulation has caused serious white pollution. With the increasing pollution and the continuous enhancement of people's environmental protection awareness, degradable resin has become a research field due to its degradation characteristics and economic characteristics. hotspots. [0003] Polylactic acid (PLA) is an environmentally friendly biodegradable material with good mechanical properties and biodegradable properties. It is easily decomp...

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Problems solved by technology

[0004] However, polylactic acid is a hard and brittle material at room temperature, with extremely low elongation at break and impact strength. When it is blown into a film, it cannot form a stable film bubble, and the film is relatively hard. Very easy to wrinkle during the process, which greatly limits its application, especially in the field of packaging

[0005] Polybutylene terephthalate-co-butylene adipate (PBAT) has high melt strength and good flexibility. It is the same thermoplastic as PLA, but the film has poor heat sealability and texture. Soft, easily deformed by stretching during stretching

[0006] In view of the complementary properties between the two, the blending of PBAT and PLA is selected, and the composite heat-sealing film prepared not only has good toughness without losing its biodegradability, but the flow rate is slower during blown film extrusion. Fast, the mixture of PBAT and PLA is difficult to achieve rapid cooling during the film blowing process. Therefore, during the film blowing traction process, it is very easy to cause film breakage and difficulty in film formation.

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