Casting film has excellent heat-sealing performance and excellent transparency, how to choose the appropriate anti-blocking masterbatch has become a difficult problem that many producers must tackle. This paper describes the composition of the salivary membrane and the selection of an anti-blocking masterbatch.
1. Overview of casting film
The fluidic film is a non-stretchable, non-oriented plain extrusion film produced by melt salivation quenching. There are two modes of single-layer salivation and multi-layer co-extrusion.
Compared with blowing film, it is characterized by fast production speed, high yield, film transparency, luster, thickness uniformity, and so on are excellent. Casting film has superior heat sealing performance and excellent transparency and is one of the main packaging composite substrates, used in the production of the high-temperature cooking film, vacuum aluminum plating film, etc., so the market is very promising.
2. How to select the casting film anti-blocking masterbatch
The key to the formulation design of casting film anti-blocking masterbatch is the material selection, matching, dosage, and mixing. The surface looks very simple, but it contains a lot of internal connections. Designing a high-performance, easy-to-process, and low-price formula is not easy, and many factors need to be considered.
The basic composition of our current PE film is as follows:
HDPE PE resin LDPE LLDPE 70%
PE film color master (w) (7%-10%): PE resin +80~85%
Filling material (w): PE resin +
1) Selection of resin varieties
To save the number of additives, the resin should be selected with the performance closest to the purpose of modification. Such as wear-resistant modification, the resin should first consider the choice of three wear-resistant resins PA polyamide (commonly known as nylon), POM (polyformaldehyde), and UHMWPE (ultra-high molecular weight polyethylene); Again such as transparent modification, the resin should first consider the selection of three transparent resin PS (polystyrene), PMMA (polymethyl methacrylate), PC (polycarbonate).
2) The selection of resin brand
For different brands of the same kind of resin, performance is also very different, should choose the performance closest to the purpose of modification. Such as heat resistant modified PP, can be selected in the thermal deformation temperature of 100 ~ 140℃ PP brand range, we should choose its heat resistant 140℃ PP brand.
3) Selection of resin fluidity
The viscosity of various plasticizing materials in the formula should be similar to ensure processing fluidity. For the material with very different viscosity, the transition material should be added to reduce the viscosity gradient.
For example, PA6 is often added as a transition material in PA66 toughening and flame retardant formula and HDPE is often added as a transition material in PA6 toughening and flame retardant formula.
Different processing methods require different flows
Different types of plastics have different mobility. Thus, plastics are divided into high-mobility plastics, low-mobility plastics, and immobility plastics, which are as follows:
High mobility plastics — PS, HIPS (impact resistant polystyrene), ABS, PE, PP, PA, etc.
Low mobility plastics – PC, MPPO (modified polyphenylene ether), PPS (polyphenylene sulfide), etc.
Immobile plastics — polytetrafluoroethylene, UHMWPE, PPO, etc.
The same kind of plastic also has different mobility, the main reason is the molecular weight, molecular chain distribution is different, so the same kind of raw material is divided into different brands. Different processing methods require different liquidity, so the brand is divided into injection grade, extrusion grade, blow molding grade, calendering grade, etc.
Different modification purposes require different liquidity, such as high filling requirements good liquidity, such as magnetic plastic, filling mesh, halogen-free flame retardant cable material, etc.
4) Selectivity of resin to anti-blocking masterbatch
Such as PPS can not add lead and copper-containing anti-blocking agents, and PC can not use antimony trioxide, these can lead to depolymerization. At the same time, the acid-base of the anti-blocking masterbatch should be consistent with the acid base of the resin, otherwise, there will be a reaction between the two.