DB-3175A/B type ordinary two-component polyurethane adhesive is a general-purpose dry composite adhesive, suitable for the composite between BOPP, BOPET, BOPA and other substrates and CPP, PE film, with better peeling Strength, good transparency.

One. Performance characteristics
1. This product has moderate viscosity and good economy in use.
2. It has good wetting performance to the substrate and excellent coating processing performance.
3. The composite film has good transparency and softness.

Two. Product index

Product name	DB-3175A main agent	DB-3175B curing agent
Exterior	Light yellow transparent liquid	Light yellow or colorless transparent liquid
Solid content (%)	75±2	75±2
Viscosity (mpa.s.25℃)	3000±1000	1500±500
Solvent	Ethyl acetate	Ethyl acetate
Mix ratio	20	4

Three、Instructions
1. Standard ratio (weight ratio): component A (main agent): component B (curing agent) = 5:1, when the air humidity is high (more than 70%) and polyurethane ink is used for printing, the curing must be increased appropriately Agent 10-20%.
2. Dilution: first calculate and weigh out the ethyl acetate required for a certain working concentration (the water content of ethyl acetate cannot exceed 200ppm, and it is not allowed to contain impurities such as alcohols and amines), and then transfer to a known weight Add ethyl acetate to the agent, stir fully in a fixed direction (for example, clockwise), add the curing agent after it is uniform, and stir again. It is best to mix the whole barrel of the main agent with the whole barrel of curing agent, because the curing dose is small, and the weighing accuracy will not be high if it is divided into several times. The viscosity of the solution should be considered when calculating the working concentration, because the viscosity will affect the coating amount and coating state.
3. Standard ratio and solvent comparison table

Working concentration (%)	A component (kg)	B component (kg)	Thinner (kg)	Viscosity (25℃, 3# Charn cup), S
40%	5	1	5.3	12.24
35%	5	1	6.8	11.69
30%	5	1	9.0	10.83
25%	5	1	12	10.56

4. Coating amount calculation: There is a rough empirical formula for calculating the coating amount of Bumeilan and laser coating rollers for reference:
Coating amount on dry basis (g/㎡)=0.2×Working fluid concentration%×Mesh depth µ×Working fluid specific gravity
The above formula cannot be applied to the electro-engraved coating roller and the pyramid-shaped embossing coating roller. The specific gravity of the 33% working solution is 1; the specific gravity of 26% is 0.96. The specific gravity of 45% is 1.04. The proportion of calculations with low accuracy can be ignored.
5. Coating amount selection: Depending on the substrate structure and application requirements, the coating amount (dry basis) can be selected between 2.5-3.5g/㎡. The coating amount of ordinary dry food packaging bags can be less, and the peel strength can be satisfied, mainly considering white spots and bubbles. The coating amount of the packaging bag that requires high peel strength should be more. The amount of glue applied is determined by the depth and working concentration of the anilox roll. The best concentration is recommended to be 25%---35%.
6. Drying: In order to make the solvent in the base film coating layer evaporate cleanly, the drying efficiency of the dryer should be improved as much as possible. The factors that affect the drying efficiency are hot air temperature, wind speed and air volume. The faster the compounding speed, the higher the drying efficiency requirements; on the contrary, when the equipment drying efficiency is low, the compounding speed can only be reduced. The wind speed and air volume of the compound machine are generally not adjusted frequently after correction, but the hot air temperature and compound speed often change. The principle of setting the hot air temperature is to low first and then high to form a temperature gradient. The purpose is to prevent the coating surface from drying too quickly and preventing the further volatilization of the internal solvent. This is often called "false drying". For example, when the nozzle wind speed of the drying box is 30 meters per second and the composite speed is about 80 meters, the hot air can be set at 50-60°C, 60-70°C, 70-80°C, depending on the substrate and coating amount.
7. Laminating: On the premise that the film is not overstretched or damaged, the temperature of the composite hot roller should be increased as much as possible, and the temperature of the hot roller can be selected between 50 and 85 ℃. Note: The temperature of the heating cylinder is not equal to the temperature of the heat roller, and the temperature of the edge of the heat roller is not equal to the temperature in the middle of the heat roller. The line pressure of the hot roller is determined by the cylinder diameter, air pressure, hardness and length of the silicone roller. The only thing that can be adjusted frequently is the air pressure. Different composite machines cannot compare the linear pressure of the heat roller with the reading of the pressure gauge.
8. Curing: The composite film from the machine should be sent to the curing room as soon as possible, and the composite film should be heated at a constant temperature of 45～60℃. The uncured adhesive will melt and level, eliminate small bubbles and white spots, and continuously mature Satisfactory bonding strength can be achieved after 36 hours. The air in the maturing room is required to circulate and flow, the purpose is to make the temperature of the maturing room consistent; the air with high solvent content in the maturing room is continuously discharged, and the solvent concentration in the indoor air is reduced through convection, which is beneficial to the continued volatilization of the residual solvent in the composite film.

Four. matters needing attention
1. The amount of glue to be dispensed is determined according to the needs. It is ready for use now. It is best to use up the glue on the same day. The remaining glue cannot be used in principle. If there is too much glue left, it can be diluted several times with a solvent and put in a closed container and stored in a cool and dry place. When working on the next day, use the remaining glue as a diluent in a small amount (about 20% or less) into the newly prepared glue. Use in liquid (not suitable for composite products with high quality requirements). If white turbidity, translucency and viscosity increase are found, it should not be used again.
2. Composite substrates such as BOPP, BOPET, BOPA, CPP, PE and other films require surface treatment. The surface tension of BOPP, CPP, PE must be above 38 dyne, and BOPET and BOPA must be above 52 dyne. In principle, BOPET and BOPA with non-double-sided processing cannot be laminated on both sides, otherwise the peel strength of the non-corona surface cannot be guaranteed.
3. The content of additives in the film, especially slip agents, directly affects the bonding strength of the composite film. It must be strictly controlled, especially when the polyethylene film is thick. Therefore, the film must be selected and selected before use. test. So as not to cause unnecessary losses.
4. This product cannot be used for the lamination of surface printing ink printing film.
5. If there are quality problems or abnormal phenomena during the glue use, stop using it immediately, keep the unopened glue, and notify our company as soon as possible so that we can send a technician to deal with it.
6. The technical opinions provided in this manual are from sincerity and are for reference only. Since each user's equipment, process and raw materials are not controlled by our factory, the user is also responsible for experimenting with the products provided by our factory to verify whether it is suitable for the proposed process and purpose.
7. Due to the continuous advancement of technology, the company has the right to modify this manual. When the manual is changed, we will not notify you separately. When you use the manual, please confirm the latest version. If there is any ambiguity, please contact us in time.
8. This product is flammable and should be paid attention to when using it.

Five, packaging and storage
Component A (main ingredient): 20 kg/barrel
Component B (curing economy): 4 kg/barrel.
This product should be stored in a cool and dry place. The storage period of the main agent is 12 months, and the storage period of the curing agent is 9 months. After opening the package, it should be used up as soon as possible and no longer stored.