M. Control the solvent ratio. Because ethyl ester is easy to volatilize, under the premise of not affecting the output and quality, more ethyl ester should be used, less toluene should be used, and toluene: ethyl ester = 1:1 ratio can be used for layer version. We found that under the condition of other conditions unchanged, the ratio of solvent was different, and the residual amount of solvent was very different
As shown in the table below

test	Solvent ratio1	Solvent ratio2	Solvent ratio3
	toluene80％ethyl ester20％	toluene50％ethyl ester50％	toluene40％ethyl ester40％Butanone20％
Residual solvent mg/m2	toluene5.2,ethyl ester3.27	toluene2.78,ethyl ester1.58	toluene1.98,ethyl ester1.37,Butanone0.64

N. Roll depth. The shallower the plate roller, the lower the residual solvent.
O. The secondary return air flow should be well controlled and should not be too large.
P. According to the inspection report to enter the next process, if the single-layer film solvent residue exceeds the standard, it is easy to drop after drying and rewinding again, but it is difficult to reduce after compounding.
3、 Solvent residue control in compound process
1. Composite materials:
The barrier property of the material has a great influence on the residual amount of solvent. For example, BOPP / PE structure, the solvent is easy to volatilize. For the structure with good barrier, such as kbopp / PE (PP), the solvent is not easy to volatilize. For the product with double barrier structure, the solvent is the most difficult to volatilize. If the compound exceeds the standard, it is difficult to remove it, such as PET / VMPET / PE kbopp / VMPET / PE
2. Type and quality of composite adhesive
Solvent free adhesives and water-based adhesives do not contain organic solvents, which can solve the problem of residual solvents. We all have such experience. For the same solvent based polyurethane adhesive, different manufacturers have different solvent residues after compounding with the same materials and the same process. This is because the soft segment contains hydroxyl group of active hydrogen, and the hard segment contains biuret group and carbamate group of active hydrogen. These groups containing active hydrogen can be found in ethyl acetate molecule Hydrogen bonds form intermolecular hydrogen bonds. The formation of intermolecular hydrogen bonds will bind the release of ethyl ester. The higher the density of hydrogen bond, the stronger the binding of ethyl ester, and the higher the residue of ethyl ester under the same conditions, so we can't change the glue manufacturer frequently in order to reduce the cost. We have done experiments under the condition that other conditions remain the same, we use the glue of different factories to dry and duplicate the single-layer products under the condition of 45 degrees in the curing room for 2.5 hours, and then use the residual solvents of the glue of factory a: toluene 3.65 mg / m2, ethyl ester 7.87 mg / m2.
The residual solvents of glue from factory B were toluene 4.02 mg / m2 and ethyl ester 21.59 mg / m2.
The residual amount of ethyl ester in the latter was almost three times that of the former
3. Influence of moisture
In the compound production, moisture not only affects the appearance quality and composite strength of printing, but also affects the solvent release.
Source of moisture
NY film is the most easy to absorb water, pet, VMPET, Al surface is easy to absorb water, BOPP, PE film is relatively good, the water contained in solvent, at the same time, due to the continuous evaporation of solvent in the production process, a lot of heat will be taken away, and the water contained in the air will be cooled on the surface of wire roller and rubber roller.
4. The influence of the compound machine on the residual solvent is mainly manifested in the following aspects
A. Design of drying channel B. configuration of inlet and exhaust air volume C. direction of exhaust air duct
D. Configuration of oven temperature
5. Composite process
A. Strictly implement the process discipline. Once the process passes the test, it is necessary to strictly implement the process. At the same time, it is not easy to change the raw materials. Any parameter change must be tracked and monitored in time.
B. Effect of coating thickness
The larger the amount of glue per unit area, the thicker the coating surface, and the solvent is not easy to volatilize.
Dongguan Beite packaging materials Co., Ltd. - located in Dongguan City, the world's manufacturing city, is a subsidiary of Beite packaging (China) Co., Ltd., with a plant area of 6000 square meters. It is a flexible packaging enterprise integrating R & D, production and sales. It has a complete set of domestic advanced production equipment, a scientific and humanized management system and a group of experienced technical personnel For backing, to provide customers with quality products and first-class service.
The company produces composite bags, roll film, fruit bags, aluminum foil bags, suction mouth bags, self-supporting bags, zipper bags, anti-static bags, special-shaped bags, etc., which are suitable for the internal and external packaging of food, daily chemicals, electronics, toys, medicine, cosmetics, industrial products and other industries.
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