Coated PVDC Barrier Packaging Film

I.   Base film

In industrialised large-scale production, the base film used for coated PVDC film is mainly BOPP, BOPET, BOPA, CPP, etc. In addition, PE, PVC and cellophane films can also be applied. The base film used for coating must be subjected to surface treatment before coating to achieve a sufficiently good surface condition to ensure that the PVDC coating is continuous and free of pinholes as well as good bonding fastness between the PVDC coating and the base film, thus obtaining PVDC coated film with good barrier properties. Good bonding fastness between the PVDC coating and the base film, so as to obtain PVDC coated film with good barrier properties.

Base film surface treatment commonly used methods are corona treatment and primer coating two categories, corona treatment can make the surface of the base film chemical reaction, produce polar groups, increase the lonely surface tension, help the PVDC emulsion in the surface of the base film infiltration, improve the effect of coating; in the corona treatment, will also make the surface of the base film to produce a certain degree of roughness, thus improving the coating and the base film between the bonding strength. The primer coating is through a specific coating, so that the base film and PVDC coating between the combination, if the primer coating selection, the application of the right primer coating, can make the PVDC coating effect to produce a significant increase, so high-quality PVDC coated packaging materials, generally without exception, the application of the primer coating, the most commonly used primer is polyurethane adhesive.

II.   PVDC emulsion for coating

PVDC coating can be used PVDC solution, can also be used PVDC emulsion, based on the need for environmental protection and cost reduction, currently in the production of industrialised PVDC coated packaging materials, generally used PVDC emulsion coating

Coated PVDC emulsion with vinylidene chloride and less Ling copolymer monomer (mainly acrylic monomers) copolymer, the introduction of copolymer monomers, so that the melt temperature of the PVDC resin down, so as to open the melt temperature and decomposition temperature of the distance between the film is conducive to film formation in order to improve the coating process performance of the PVDC emulsion, copolymer monomers are usually controlled at a relatively low level (only about 10%), so that the PVDC resin has excellent oxygen barrier, moisture resistance.

Coating with PVDC resin, in addition to good barrier properties, but also must have a good coating processability, anti-adhesion and good emulsion storage stability and other coating process performance.

III.   PVDC coating process

Process

Base film - surface corona treatment - coated with primer - infrared drying - hot air drying - PVDC (surface adhesive) - infrared drying - hot air drying - coiling - ripening - product

Note:Rapid drying by far infrared can prevent the coating surface from crusting and help the coating dry.

The function of aging is to make the PVDC coating crystallise uniformly and improve the barrier property of the PVDC coating. At the same time, aging at the set temperature can prevent the coating from cracking due to uneven crystallisation, so as to obtain products with high barrier property.

If the film is to be coated on both sides, repeat the above coating process.