The meaning of down flow casting film is introduced first. The flow casting film is a non stretching, non oriented flat extrusion film produced by melt salivation of the flow casting film machine. There are two ways of single-layer salivation and multi-layer co extrusion salivation. Compared with blown film, it is characterized by slow production speed, low output, excellent transparency, luster, thickness uniformity, etc. However, do we know the importance of resin selection when making tape casting film with message ink? What kind of resin should we choose?
(1) First is the selection of resin varieties
The selection of resin varieties is based on whether the desired tape casting film can be made. The resin shall be selected with the performance closest to the modification purpose, so as to save the use of additives. For wear-resistant modification, the three small wear-resistant resins PA, POM and UHMWPE should be selected first; Again, if the resin is uniformly modified, the three small homogeneous resins PS, PMMA and PC should be selected first.
(2) Next is the selection of resin brand
Many manufacturers do not attach great importance to this when making cast films. The brands of the same resin are different, and their performance differences are also very small, so the brand closest to the modified purpose should be selected. For example, heat resistant modified PP can be selected within the range of PP grades with thermal deformation temperature of 100~140 ℃. We should select the PP grades that are resistant to 140 ℃, such as Xiaohan Oiled PP-4012.
(3) Once again, it is the choice of resin fluidity
The abstraction of this step can only be realized after trying, and there is no clear standard. The viscosity of various plasticizing materials in the formula shall be close to each other to ensure the processing fluidity. For materials with widely different viscosities, transition materials shall be added to reduce the viscosity gradient. For example, PA6 is often added as the transition material in PA66 toughening and flame retardant formulations, and HDPE is often added as the transition material in PA6 toughening and flame retardant formulations.
Different processing methods require different fluidity.
Different varieties of plastics have different fluidity. From then on, plastics are divided into low fluidity plastics, high fluidity plastics and non fluidity plastics, as follows:
Low fluidity plastics – PS, HIPS, ABS, PE, PP, PA, etc.
High fluidity plastics – PC, MPPO, PPS, etc.
Never flowing plastic — PTFE, UHMWPE, PPO, etc.
The same variety of plastics also has different fluidity, mainly due to different molecular weight and molecular chain distribution, so the same raw materials are divided into different brands. Different processing methods require different fluidity, so the grades are divided into injection molding grade, extrusion grade, blow molding grade, calendering grade, etc.
Different modification purposes require different fluidity. For example, high filling requirements require poor fluidity, such as magnetic plastics, filler mesh, halogen-free flame retardant cable materials, etc.
(4) Finally, it is the selectivity of resin to additives
The literal meaning of the promoter is just as the name implies, which is the catalyst to promote the smooth shaping of the cast film. For example, PPS must not add lead and copper containing additives, and PC must not use antimony trioxide, which can lead to depolymerization. In addition, the acid-base property of the auxiliary agent should be the same as that of the resin. If so, they will react with each other, causing very serious consequences
The tape casting film machine can be used to produce PE, CPE, EVA and other plastic films, as well as transparent films, embossed films (patterns can be based on customer samples), optical films, etc.
Properties of cast film.
The film is widely used: it can be used for the bottom film of sanitary products, such as sanitary napkins and diapers; Daily articles, such as disposable gloves, shoe covers, shower caps, sleeves, aprons, surgical clothes, cleaning clothes, tablecloths, umbrellas, shower curtains, etc. And lining film, packaging film, and usually perforated film base film and various film rolls.