-
Q Do different laminated materials, different uses and different post-processing affect curing temperature and time?
A Usually, different materials, different uses need different curing temperature and time; And the curing time of different post-processing methods can also be changed (extended or shortened appropriately). For example, lower curing temperature and longer curing time are needed after PE film lamination and aluminized film lamination. This is conducive to solving the problem of the increase of friction coefficient after PE film laminate curing, and the problem of aluminum plating transfer after the laminate curing of aluminized film.
-
Q The difference of drying and curing?
A In the chemical industry, drying often refers to the process by which moisture (or solvent) in materials is vaporized by heat energy and the resulting vapor is removed by inert gases
Curing is refers to the chemical reaction that can be achieved by adding adhesive such as photocuring which is the curing process of monomer, oligomer or polymer base material under light induction.
-
Q The common curing temperature and curing time of solventless lamination?
A The common curing temperature of two-component adhesive is 35 ~ 45℃, depending on the different grades of adhesives, and often also related to the lamination structure and environment
The common curing time is 24~48 hours, depending on the grade of adhesive, lamination structure and post-processing method. Usually, the curing time can be shorter when the post-processing is slitting or laminating, while the curing time is longer when the post-processing is bag-making.
-
Q The environmental requirements of being solventless? Why does humidity affect solventless lamination?
A Solventless two-component adhesives usually have certain environmental requirements, which generally require the relative humidity of the environment to be below 70%.
Because the moisture in the air may react with the -NCO group in the main agent. If the relative humidity is too high, it may cause excessive consumption of -NCO, which will lead to insufficient reaction of the curing agent -OH group, resulting in abnormal conditions such as poor adhesive curing.
For the single component adhesive, the reaction with moisture is a necessary condition for curing, so the paper moisture content or the relative humidity around the laminating area is higher conducive to the curing of the adhesive.
-
Q The common viscosity of solventless lamination adhesive?
A The viscosity of different products from different suppliers at home and abroad is quite different. For example, the viscosity of common two-component adhesives ranges from 800 to 3000mPa·s, and some viscosity reaches 4000mPa·s at room temperature. However, the viscosity of single component glue is usually high, and sometimes the viscosity can reach 10000mPa·s or higher at room temperature. It needs to be heated and melted before use.
-
Q The solid content of solventless adhesive?
A Solid content is the percentage of the mass of the adhesive after it has been completely dried or cured under specified conditions compared to the mass before drying or curing began. In the volatile solvent adhesive is also called "non-volatile component content ratio".
The solid content of solventless adhesive is 100% theoretically.
-
Q What is PUR adhesive?
A The reactive polyurethane hot melt adhesive, commonly known as PUR adhesive, is solid at room temperature and liquid after heating and melting by polyol compound and isocyanate compound. It does not contain volatile components, and can react with the moisture in the air or paper after curing to form a high fastness, good weather resistance adhesive layer.
-
Q What is retort adhesive, medium resistant adhesive, UV adhesive, room temperature adhesive?
A Adhesive used for retort packages at 120℃ or above is called retort adhesive.
Adhesive used in the laminating packaging to hold acid, alkali or corrosive packaging is called medium resistant adhesive.
Adhesive that can be cured by UV irrigation is called UV adhesive
Adhesive that can be coating and laminating at room temperature is called room temperature adhesive.
-
Q VOC stands for Volatile Organic Compounds.
A VOC stands for Volatile Organic Compounds.
The definition of VOC may vary among different organizations. Here are some examples:
-
According to the ASTM D3960-98 standard: Any organic compound that participates in atmospheric photochemical reactions.
-
The definition by the U.S. Environmental Protection Agency (EPA): Volatile organic compounds are carbon compounds that participate in atmospheric photochemical reactions, excluding CO, CO2, H2CO3, metal carbides, metal carbonates, and ammonium carbonate.
-
The World Health Organization (WHO, 1989) defines Total Volatile Organic Compounds (TVOC) as a general term for volatile organic compounds with a melting point below room temperature and boiling points between 50-260°C.
-
International standards ISO 4618/1-1998 and the German standard DIN 55649-2000, which deal with general terms for paints and varnishes, define VOC as any organic liquid and/or solid that can volatilize at normal temperature and pressure. The DIN 55649-2000 standard adds a specific condition for VOC determination, stating that any organic compound with a boiling point or initial boiling point below or equal to 250°C under normal pressure is considered a VOC.
