High-speed packaged multilayer co-extrusion, thermal forming and drawing bottom film and production process

Abstract

The invention discloses a high-speed packaged multilayer co-extrusion, thermal forming and drawing bottom film which comprises a surface layer, a block core layer and a heat sealing layer, wherein the block core layer contains at least one polyamide layer; the heat sealing layer is selected from one of a POP layer, a POE layer and a sarin layer; the surface layer is a polyamide surface layer or a polypropylene surface layer. The high-speed packaged multilayer co-extrusion, thermal forming and drawing bottom film adopts one of the POP layer, the POE layer and the sarin layer as the heat sealing layer; as the three resin materials are high in low temperature heat sealing property and anti-fouling heat sealing property, the thin film can achieve the heat sealing effect which is the same as the heat sealing layer in the prior art under a short-time heating condition, and is more suitable for high-speed packaging. The invention further discloses a production process of the high-speed packaged multilayer co-extrusion, thermal forming and drawing bottom film.

Description

technical field [0001] The invention relates to the technical field of co-extrusion thermoforming stretch bottom film, in particular to a high-speed packaging multi-layer co-extrusion thermoform stretch bottom film and a production process. Background technique [0002] Stretch film is tough, has high impact resistance and penetration strength, good self-adhesiveness, transparency, does not expand the volume of goods after packaging, is shockproof, moisture-proof, and has strong protection. It is a very popular packaging form in the world. Setting a barrier layer in the stretch film can improve the barrier performance of the film body to water vapor and / or oxygen, and help to maintain the taste and freshness of food. [0003] In the published patent documents, Chinese patent CN1733397A discloses a biaxially stretched co-extruded high-barrier substrate film, which includes a barrier layer, an adhesive layer and a heat-sealing layer, wherein the heat-sealing layer resin is On...

AI Technical Summary

Problems solved by technology

However, on high-speed stretch film packaging equipment, the ultimate operating speed can reach more than 25 cycles per minute. Under this condition, the preheating / forming / heat-sealing conditions of materials have changed greatly. Conventional materials have Unable to adapt to such operating requirements, mainly reflected in two aspects: low-temperature heat-sealing performance and anti-pollution heat-sealing performance

[0005] Secondly, the stretched film in the prior art is usually produced by down-blowing water cooling or casting method, both of which are quenching processes, and the crystallinity of the material is relatively low

However, since the structural layer in the thermoforming material is generally made of nylon material, nylon is very easy to absorb water. After the film is formed, the nylon material will also interact with the water vapor in the air, and the water molecules will enter the interior of the nylon material, playing the role of internal plasticization. , reduce the glass transition temperature of the overall nylon material

In the prior art, the quenching temperature is 10-12°C. At this temperature, the crystallization of nylon material is not perfect and complete. After the glass transition temperature is lowered, the balance of crystallization is broken, and secondary crystallization of nylon will occur, which is manifested as The material will shrink to a certain extent, and the haze of the film will also increase to a certain extent

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