The classification of release paper can be classified into plastic release paper and non-plastic release paper; it can also be classified according to release agent, silicone release paper and non-silicon release paper.
There are plastic release papers, because the release agent has certain permeability. If there is no certain barrier, the release agent will penetrate into the paper, resulting in poor curing and excessive use of the release agent (too high cost). factor. Therefore, the paper needs to be coated with plastic (commonly known as laminating). In China, polyethylene (PE) particles are generally used for laminating, and the melt index is required to be around 7. Domestic PE particles generally use 1C 7A from Yanshan Petrochemical. Divided into single-plastic release paper and double-plastic release paper; non-plastic release paper, mainly glassine, CCK and other specially processed release papers.
1. Coated release paper
After the base paper is coated, a release agent is coated on the coated surface to produce a release paper.
Because there are paper wool and fibers on the surface of the paper, the coating must reach a certain amount to ensure that there is no penetration point, to ensure that the silicone oil will not penetrate into the paper, and that there will be no peeling defects. Generally, the coating amount of coated paper is 16 grams per square meter. It is said that Wenzhou area has achieved 11~13 grams per square meter, which is quite close to the coating data of advanced foreign equipment. Theoretically speaking, as long as the tape can be peeled from the release paper, the lower the amount of coating is allowed.
Laminated release paper is divided into single shower and double shower. Generally, single-sided release paper is single-coated, of course, there are also double-coated single-sided release papers, because the thicker coating on the release surface is generally 20 grams, and the non-released surface is generally thinner by 15 grams. Compared with this type of release paper smooth.
If it is coated paper with a double-sided coating amount of 22 grams, it is more suitable for double-sided release paper.
Laminated release paper generally uses wood pulp paper, especially in the electronics industry. If straw pulp paper is used, there will be a lot of paper scraps and easy edges during die cutting.
Whole wood pulp paper is generally called kraft paper, such as natural kraft paper (commonly known as: Benniu), white kraft paper (commonly known as Bainiu), yellow kraft paper (commonly known as Japanese yellow color cow), blue kraft paper (commonly known as Indonesian blue color cow).
Of course, we can also use double offset paper made of wood pulp as base paper, more use photographic paper as base paper, and use coated paper, white paper, cow card, milk card, etc. as base paper.
As long as the paper-plastic fastness of the film can meet the requirements, as long as the film has no penetration points and the film is even and flat, it should be said that any paper can be used as base paper.
2. Glassine release paper
Glassine base paper is overpressured and coated with a release agent to produce release paper.
Because Glassine has been supercalendered, the firmness of the paper is very good, so it is especially suitable for die-cutting processing plants.
Since domestic glassine can only produce 60~80 grams of basis weight, die-cutting factories prefer to use more than 100 grams of basis weight, such as 120 grams and 140 grams. It has a certain degree of transparency, good stiffness, and good die-cutting performance. All rely on imported base paper, but because the minimum amount of imported base paper is 20 tons per container, and it must be booked 3 months in advance, the full amount of the order must be paid. There are many release coating suppliers in China that don’t think it makes much sense.
3.CCK release paper
CCK base paper is a release paper produced by coating a layer of special clay on the surface and then coating a release agent.
Because of its excellent high-temperature resistance, it is widely used in the carbon fiber industry.
The clay on the surface of the CCK base paper can easily damage the silicone, so there are still a few domestically produced CCK release papers that can really pass the customs.
4. Other release paper
In addition, some release papers are widely used in many industries, and some do not use release agents. For example, label printing factories often apply a layer of varnish where release is needed, and it will also have a certain release ability. Of course, the performance of the glue is very weak. Otherwise, this release ability is futile. In addition, some release papers produced with some special glue formulations account for very little market share in the overall market.
There are few genuine papers used in the electronics industry (release papers with stable quality and guaranteed supply) produced by regular factories, mainly garbled papers (release papers that have been used once abroad or have quality defects). Glue factories basically use genuine paper.