ã€Chinese Packaging Network News】 composite film in the aging easily lead to low strength, increased friction coefficient, delamination and other issues. Huayin Xiaobian has combined the practical problems of the printing plant with the above issues. After testing, the corresponding solutions are given. I hope to help you!
1, composite PE film strength is low
A factory in Hunan produces BOPA/PE bags that are returned due to low strength. After the two films were peeled off and wiped with a finger on the PE film, there was a feeling of smoothness between the two fingers. The film contains more slip agent. The adhesive used in this product is PU-1850 which is resistant to lubricants.
After founding in the color printing plant, the temperature of the curing chamber was parallel to the heating source, and the distance from the heat source was only 30 cm to 40 cm. Under such control, the heat source would be in a stopped heating state for a long time. The actual aging temperature was less than 50°C. of. And the opening time of power heating is less than 16 hours. Adjust the thermocouple position, extend the curing time, and achieve a peel strength.
In the case of a PE film with a high level of slip agent, an adhesive with a certain resistance to the slip agent should be used. Membrane roll into the curing room as soon as possible after the machine, and appropriately increase the curing temperature. General ester-soluble two-component polyurethane adhesives have poor natural maturation and slip resistance properties.
2, increase the friction coefficient
The production of BOPP/VM-PET/PE-structured reels in a factory in Guangdong has always been a problem in winter production. In June, the friction coefficient increased and the packaging machine could not be used normally. Instead of natural ripening, the membrane roll still cannot be used.
This product is made of PE film with a thickness of 30μ. When compounding, the cooling roller cannot pass cold water, and the surface of the cooling roller is warm. The heat of the film from the oven before rewinding is still, and the film is warm when rewinding. Although it is natural aging in the workshop and the high temperature in the summer (at 30 oC in the workshop at 10 o'clock in the morning), the heat of the film roll is not easily dissipated, and it is actually in a hot state.
The composite film was taken on site and placed in 27°C and 45°C environments for about 20 hours. The smoothness at 27°C was good, the composite film placed at 45°C was astringent, and the smoothness was significantly reduced. The effect of the smoothness of the product is greater.
Similar to the temperature sensitivity of some thin transparent CPPs, the CPP coefficient of friction before compounding is less than 0.1, but it can only be naturally cured after compounding.
3, cooking delamination
A factory in Wenzhou produced brine egg bags and sterilized at 115°C for 30 minutes in the food factory. BOPA layering occurred in the top layers of the retort, and Huai Mo was transferred to the CPP. The technicians of the color printing factory think that the quality of the adhesive and the amount of glue applied can meet the requirements of the product. The curing at 50°C to 55°C for 48 hours is also desirable. The problem is that the possibility of ink is high.
After the sample bag was matured at 55°C for 24 hours again, there was no delamination at 121°C for 30 minutes. All delaminated samples that had been steamed together showed delamination. The direct manifestation of this problem is the transfer of ink, and the cause of this phenomenon is insufficient ripening. Later, when the company’s other technicians arrived at the plant, the actual maturation time was about 36 hours. The plant's process requirements were inconsistent with actual implementation.
A bookcase, or bookshelf, is a piece of furniture with horizontal shelves, often in a cabinet, used to store books or other printed materials. Bookcases are used in private homes, public and university libraries, offices and bookstores. Bookcases range from small, low models the height of a table to high models reaching up to ceiling height. Shelves may be fixed or adjustable to different positions in the case. In rooms entirely devoted to the storage of books, such as libraries, they may be permanently fixed to the walls and/or floor.
A bookcase may be fitted with glass doors that can be closed to protect the books from dust or moisture. Bookcase doors are almost always glazed with glass, so as to allow the spines of the books to be read. Especially valuable rare books may be kept in locked cases with wooden or glazed doors. A small bookshelf may also stand on some other piece of furniture such as a desk or chest. Larger books are more likely to be kept in horizontal piles and very large books flat on wide shelves or on coffee tables.
Storage Bookcase,Solid Wood Bookcase,Rustic Bookcase,Wood Bookcase,Wooden Storage Bookcase,Wood Storage Bookcase
Jinan Tri-Tiger Technology Development Co., Ltd , https://www.tritigerwooden.com