Five test methods for polyethylene film
(1) Melt index The melt index indicates how many grams of polyethylene can be extruded from a 2.08 mm die at a temperature of 190 ° C and at a pressure of 0.3 MPa (3 kgf/cm 2 ) over ten minutes. This method has been approved by the International Organization for Standardization ISO (R292-1963 Method a) and is used to indicate the melt viscosity of the polymer material. This method requires a more expensive equipment and the melt index is generally not measured by the film supplier. However, complete information on the melt index, density, friction, strength properties and optical properties of various polyethylene materials is available from the raw material supplier. (2) Coefficient of friction The amount obtained by measuring the frictional resistance between the two surfaces of the same film is the coefficient of friction. This is done by using a sliding body that adjusts its own weight to accommodate the sliding surface area, pulling it over the surface of the film, and measuring the sliding friction with a strain gauge. Adjust the instrument to zero position, the sliding body and the film should be freely suspended, and the maximum value of sliding friction is one. (3) Glossiness Gloss is a measure of the smoothness of the surface of a film. A piece of the film sample was attached to the black glass piece of the standard test device with a strip of glue, and the film was irradiated with light at an angle of 45 or 60 degrees on the same plane. The intensity of the reflected light is then measured and compared to the intensity of the light reflected from the uncoated glass sheet to determine the gloss value. (4) Photo-haze Film haze is generally expressed by the light scattering power of the film. The test method specifies that the sample has a thickness of 0.038 mm and the sample is fixed so that light passes through the film. The haze is measured as the ratio of the intensity of the transmitted light to the incident beam direction that is greater than 2.5 degrees and the total transmitted light intensity. Haze is a measure of the turbid appearance of a film. (5) Permeability Permeability is a measure of the ability of a gas to pass through a film under certain climatic conditions. The simplest description of the test method is to dissolve the gas or vapor on one side of the film and evaporate on the opposite side through the film under the action of a concentration gradient. After a short period of time, equilibrium is reached, as long as the pressure difference across the two sides of the film remains constant, the gas passes through the film at a constant rate. Permeability is expressed by the volume multiplied by the thickness per unit area, time and pressure difference. Cross-Linking Agent,Cross Linked Polymer,Crosslinking Agents In Polymers,Collagen Cross Linking Ningbo Actmix Rubber Chemicals Co.,Ltd. (Ningbo Actmix Polymer Co.,Ltd.) , http://www.actmix-chemicals.com