Solvent-free cooking composite membrane process control

Solvent-free cooking compound although there are environmental protection and energy saving, safety and health, and reduce the cost and other significant advantages, with broad prospects for development, but at present domestic high-temperature cooking solvent-free glue and composite technique is not mature enough, the compound cooking compound membrane products in comprehensive properties such as heat resistance, medium resistance and peel strength, also can't keep up with solvent adhesives on the use of adaptive also needs to improve. So, boiled for solvent-free composite membrane, either from the perspective of the selection and determination of the process of glue, all should be careful to test and verify, not without a kind of mass production. In general, enterprises in the use of high temperature resistant solvent-free composite process, from the aspects of materials, attention should be paid to the following: 1, PET corona treatment value amounted to less than 50 mn/m or more, can affect the peel strength of composite, so the computer to do test before use. 2, AL if pollution is severe, and produces composite fastness is not high, especially after high temperature cooking, take off a layer stripping of bad happens. So the aluminum foil should choose high surface cleanliness, no dust pollution, surface tension in more than 72 mn/m A grade, when computer is used to check. 3, BOPA due to the molecular structure of the amide group, to keep its high polarity, surface tension, up to 52 mn/m, when it as high-temperature cooking the middle tier of the composite membrane, its not the corona surface wet tension if reach 48 mn/m or more, they are not a corona surface composite fastness can not guaranteed, easy to cause the cooking layered composite membrane; At the same time because of a large number of amide group in the molecular structure of polar group, leading to the surface, easy to absorb the same polarity big water molecules in high-temperature cooking a two-component polyurethane adhesive for composite, also easy to cause the complex not firm. 4, RCPP for RCPP, is must pay attention to its surface wet tension, one by one before computer composite volume testing, if above 40 mn/m, can be at ease use, if only 38 mn/m, you need to verify and then determine whether to use; The second is to focus on RCPP membrane surface precipitation, precipitation, to cause a decline in the composite stripping force layered, even affect the complex appearance and health of products at the same time, three is test by RCPP model, formula without test can't change, avoid RCPP performance can not meet the demands and composite stripping force and high-temperature cooking stratification. 5, printing ink must choose high-temperature cooking inks, high-temperature cooking solvent-free composite products due to poor printing ink layer when cooking. Cooking products using solvent-free composite production manufacturer is relatively few, although many of the test manufacturer can meet the requirements, but the stability of the batch production and the risk remains to be discussed. Cooking temperature to distinguish, the solvent-free cooking process is mainly suitable for 121 ℃ cooking products, 135 ℃ cooking products are rarely used, and this is mainly because no solvent adhesives solvent-free process is not very mature, to further improve and perfect also need adhesives. Even 121 ℃ transparent type of cooking products, if improper control in the process of the operation, also can appear after cooking torn bags, such as hierarchical anomalies. Generally speaking, we can from the material, the temperature and humidity, the gluing quantity, to strengthen the control winding and curing, etc. A smaller, material thickness deviation because there was no solvents cooking composite membrane composite glue quantity is very small, only a dry type composite 1/2 ~ 1/3, namely around 2 g / ㎡, and requirements for the thickness deviation of each layer material is very small, especially the inner material RCPP thickness control. In general solvent-free composite cooking products, lining material can be in more than 50 um, and the gluing quantity is only 1. 5 ~ 2. About 5 um thickness. If material thickness deviation is large, can cause the composite semi-finished products after winding, in solvent-free adhesives movement within the roll of film, causing the materials on the position of the thin glue quantity is large, the location of the material thickness on the glue quantity is small. This is because the location of the material compared to the position of the thick thin winding large internal stress, which can cause by material thick glue to flow direction of thin place, causing unqualified product local position cooking effect after curing or stratified phenomenon. Second, the influence of temperature and humidity on the curing process of curing solventless adhesives is actually solvent-free NCO group of main agent and curing agent OH groups under certain temperature and humidity of the reaction process, so the reaction of the solventless adhesives completely degree affected by curing agent ratio of main agent and humidity, and high-temperature cooking products because the gluing quantity larger than ordinary products, the main agent curing agent ratio and humidity effects on curing adhesive is bigger also. Therefore in the actual production, to adjust the corresponding main agent according to different areas in different seasons curing agent ratio. If the winter dry season and summer monsoon rains, the air humidity vary widely, the same product in the two seasons production is going to do a slight adjustment, the proportion of glue or incomplete reaction phenomena will appear adhesives, will affect the effect after cooking cooking composite membrane products.