Teach you how to choose the PVC material and directional judgment in the production of inflatables
In the production of air models, how to choose the material is also directly related to the production of the product’s beauty and service life, here to talk about how to choose the material and vertical and horizontal judgment.
1. the appearance of the identification of the selection of materials.
The production of air mold PVC film of certain characteristics, as long as the sense can be identified. The Ministry of Light Industry issued a standard for blow molding film, the appearance of the film requirements. The film should be free of bubbles and perforations, black spots, impurities, crystal points, decomposition lines, hanging lines, thick channels, etc. There are specific requirements for film rolls to be rolled flat. The thickness of the blown film often fluctuates in the film volume, and this unevenness accumulates, and the phenomenon of ring-shaped thickening will appear on the film volume, so whether the film volume is rolled flat, with or without the phenomenon of ring-shaped thickening, should draw attention.
The pattern of the embossed film should be uniform and consistent, and the printed film should have a clear pattern, and there should be no pigment dispersion caused by bad color spots, color spots, and color paste should not appear on the back of the film.
2. Judgment of vertical and horizontal
Judging the longitudinal direction (i.e., the direction of advancement after the film is led from the calender or extruder) and the transverse direction is of certain significance to film users. The following two methods are introduced to judge the longitudinal and transverse direction of film.
1) Using the fish eye to determine the film longitudinal and transverse although the production of film process conditions are very strict, but the film made often contains some tiny impurities, under the pressure of the pressure roller or die lip pressure, will be oriented along the direction of operation, the film is viscous flow, state, so in the forward direction of the operation can be seen behind the impurities (in rare cases will also be in front of the impurities) appear a circle of film material less “swimming vortex”. These elongated, fish-eye-like areas are often used to determine the longitudinal direction of the film, especially in transparent films. Sometimes a magnifying glass or microscope is needed to see them clearly. However, the fisheye on the surface of the heat-treated hard film, saliva film or film with calendering or coating, and film with more fillers and pigments is often not very obvious, so it is difficult to judge by this method.
2) Using the longitudinal and transverse physical properties are different to determine the longitudinal and transverse due to the different physical properties of the film longitudinal and transverse, so the strength difference can be measured to determine the longitudinal and transverse, the longitudinal strength of the film is generally higher than the transverse. Also can be used to determine the film heating size change method, longitudinal often appear obvious shrinkage.
