Analysis of common problems in the production of t

Analysis of common problems in composite film production II

6. Wrinkle of composite film

transverse wrinkles appear in composite products, especially at the two ends of the drum. The majority of such wrinkles are formed by the formation of "tunnel" on one substrate and the protrusion of another substrate

6.1 on materials:

6.1.1 the initial adhesion of adhesive is insufficient

6.1.2 insufficient surface tension of substrate

6.2 process:

6.2.1 two kinds of base films (1) have been damaged when removed (such as pump sealing gasket); (2) The price of components is low (such as column lining filter); (3) Risk of damage when reinstalling the original parts; (4) The unwinding tension of regularly replaced parts is not suitable, one is too large and the other is too small. For example, BOPP/Al composite. If the BOPP tension is too large, the drying channel is heated and stretched, and the Al tension cannot be large. In addition, the elongation is small. After composite, BOPP cooling shrinkage leads to aluminum foil protrusion, and transverse "tunnels" appear one by one

6.2.2 insufficient and uneven glue application leads to poor adhesion and wrinkles in local areas

6.2.3

the winding tension is too small, the winding is not tight, and there is relaxation after compounding, which provides the possibility of shrinkage for the substrate to be shrunk. If the winding tension is large, the winding is tight and compacted, and it is sent to the curing room for curing immediately after getting off the machine, even if the process is not suitable, wrinkles will not appear

6.2, 4 the oven temperature is too low and airless, there are too many residual solvents, the adhesive drying is insufficient, and the adhesive force is insufficient, which makes it possible for the two kinds of base films to displace each other

7. Poor composite fastness

7.1 materials:

7, 1, 1 choice of adhesive, composite manufacturers hope to use one kind of adhesive for all composites. In fact, the so-called universal type is also a desire of rubber manufacturers. Yh2000 and yh2000s are relatively successful. For example, yh2000s can be used for all composites except cooking, including Al composites. However, compared with the special glue, the peel strength difference is still large. Usually, special glue is required for the composite of cooking film, aluminized film and anti dielectric film

7.1.2 when the base material, PE and CPP film are used for compounding, the surface tension should not be less than 38 dyne. When PE and CPP just get off the machine, the surface tension should be more than 43 dyne. However, PE and CPP have a feature that the surface tension drops very quickly after getting off the machine. Generally, 38 dyne can be maintained within one month and 35-36 dyne can be maintained within three months. Therefore, in addition to less purchase and less stock, PE and CPP should adhere to the detection of dyne value before getting on the machine. Sometimes, this phenomenon occurs, The composite strength is OK when it is just off the machine, but it is found that the strength decreases the next day. What is the reason? PP and PE need to add heat stabilizers, antioxidants, anti adhesion agents, slippery agents, etc. during processing or film making. These substances will continue to transfer and exude from the interior of the film to the surface. If the amount of additives is large, it will cause a significant decline in the peel strength. Generally, it can appear in 7 days at room temperature, and it may cause a decline in the peel strength after 24 hours in the curing room

7.2 ink:

7.2.1 the fastness of the ink is poor, and the ink transfers in a large area during stripping. "Reason: the permeability of the glue to the ink is poor, or the resin in the ink is unqualified, or the glue coating amount is insufficient, you should use high solid content and low viscosity glue or change the ink. When an experienced manufacturer compounds the full bottom ink, increase the coating amount by 10%

7.2, 2 the fastness of the ink is good, but the peel strength of the surrounding non ink is low. "Reason: the batch of ink anti adhesion agent is excessive

7.3 process:

7.3.1 the coating amount of glue cannot go up

7.3.2 the temperature of the compound roller is too low, and the glue activation can fully meet the heating requirements of the car parked outdoors at noon in the hot summer in tropical countries, which is quite obvious in the full bottom Al compound

7.3.3 different processes should be adopted for special structures: PET/Al/PE and PET/VMPET/PE

8. how to make aluminized composite film

8.1 choose the appropriate glue: yh501s (patented product)

8.2 select the appropriate VMCPP and VMPET. When we developed and promoted yh501s, our company has carried out quality tracking for the products of all well-known domestic coating manufacturers, and found that the VMCPP and VMPET of different manufacturers are very different after compounding. Foshan Taiyang, Wuxi Huanyu, Danyang Daya, Anhui

8.3 process:

the temperature of the oven and the composite roller is reduced by 5-10 ℃ respectively

the temperature of curing room shall not exceed 45 ℃

pet/VMPET/PE (CPP) is cured for 1-2 hours after the first pass of compounding. The analyzer belongs to the scientific analysis and testing instrument in the integration of opto electric machine. The second pass of compounding is performed

if the weather is dry, please reduce the curing dose by 10%