Zhejiang Tiantai Duobang Packaging Materials Co., Ltd

The peel strength of composite film is a major problem perplexing the soft bag factory, and there are too many factors that may affect it. Once the peel strength changes, the final packaging quality will be problematic. This paper analyzes the factors affecting the peel strength from two aspects of production technology and raw materials for reference.

1、 Production process

1. Insufficient glue amount

(1) The glue concentration is low. Determine the required amount of glue according to the structure and purpose of the product, and allocate the appropriate glue concentration.

(2) When the glue liquid refluxed on the scraper, the bubbles were not eliminated in time. At the two edges of the glue roller, a piece of paper is bonded respectively, so that the glue liquid on the scraper can delay the reflux time in the process of reflux to the glue tank, and provide sufficient rupture time for the glue liquid bubble.

(3) The glue roller was not cleaned in time, causing mesh blockage. Before stopping the machine, clean the glue roller with solvent, and during the cleaning process, brush it continuously with a capillary copper brush; At the same time, according to the continuous reduction of glue amount (set a lower limit, such as 3 g / m2), if it is lower than this lower limit, it must be cleaned regularly.

(4) If the hardness of the press roll is low, the press roll with higher hardness shall be used.

(5) Match the number of wire rollers with the amount of glue applied. The size of the gluing amount is one-to-one corresponding to the number of lines of the wire roller. Therefore, after determining the gluing amount, the matching wire roller must be selected.

(6) The pressure is too high, which causes the rubber roller to bend and deform, resulting in insufficient local rubber amount. Properly control the pressure of the press roll to minimize this bending deformation of the rubber coating roll.

(7) The glue liquid is a viscous fluid. In the production process, the speed is high, resulting in insufficient glue on some parts. Strictly control the linear speed and do not exceed the linear speed required by the process.

(8) The ink layer is too thick, which is used as a glue carrying film in the compounding process. During gluing, the ink layer consumes a certain amount of adhesive, resulting in insufficient gluing. For full-size printing materials, increase the amount of glue and curing agent when compounding.

2. Drying temperature

(1) The drying temperature is low, and the wind speed / air volume is insufficient, resulting in incomplete volatilization of the volume. Increase the drying temperature according to the step temperature. If conditions permit, try to raise the temperature of the third stage a little higher and increase the wind speed / air volume.

(2) The drying temperature is too high, causing conjunctiva. Control the effective drying temperature.

(3) The drying effect is poor when printing. Especially when printing composite colors, poor drying results in poor affinity between inks, resulting in low peel strength.

3. Composite part

(1) Low composite temperature

After drying in the oven, the adhesive film loses its fluidity, but there is still a certain creep performance inside, which increases with the increase of temperature, thus improving the composite strength of the composite. Therefore, the influence of temperature in the composite cannot be ignored, and the effective composite temperature should be ensured.

(2) Insufficient compound pressure

After drying in the oven, the adhesive film loses its fluidity, but there is still a certain creep performance inside. This performance increases with the increase of pressure, and is conducive to secondary smoothing and the reduction of minor defects. Therefore, the pressure must be large enough.

(3) The composite included angle is too large

If the included angle is too large, it can be imagined that during the compounding process, the contact surface with air will increase, so it is possible to bring in a certain amount of air, which will affect the compounding quality, especially the water vapor in the air, which will react with the curing agent in the adhesive film, resulting in incomplete curing and bubbles. Therefore, the composite included angle should not be too large.

4. High ambient humidity

The humidity in the environment is high, which brings many quality problems in the compounding. For example, during the gluing process of the glue roller, the ethyl acetate in the glue liquid will continuously volatilize, and the volatilization of ethyl acetate will take away a certain amount of heat, causing local cooling, so that a large amount of water vapor in the air condenses on the paint stick and flows back to the glue tank, and the water reacts with the curing agent in the glue to form the phenomenon of insufficient curing agent.

2、 Raw materials

1. Film material

(1) The surface tension is low (Corona value is low), which cannot meet the standard requirements. Corona treatment is done in the composite process to oxidize the surface of the film from non-polar to polar, increase the surface roughness and improve the surface tension, so as to improve the wettability of the adhesive.

(2) The aluminizing effect of aluminizing film is poor and is transferred in the production process. Formulate aluminum plating strength standard and enhance aluminum plating strength test. Select products from well-known enterprises.

(3) If the storage time is too long, the surface shall be cleaned before the auxiliary agent in the film is precipitated and compounded.

(4) If the storage time is too long, the film surface will be aged and used in time to shorten the storage time.

(5) If the storage time is too long, the moisture absorption method of the film surface is the same as above.

2. Adhesive

(1) Misuse of adhesive model. Choose the correct adhesive model and do not mix them.

(2) The adhesive is placed for a long time, and the moisture in the air dissolves in the adhesive, which consumes the curing agent. It is used and prepared now. For the remaining glue liquid, it can be used as the diluent of the same adhesive next time.

(3) The unused adhesive can be used after placing. It cannot be used again as a diluent of the same adhesive.

3. Ethyl acetate

The purity of ethyl acetate is not up to standard, and water and alcohol substances are on the high side. Use ethyl acetate in strict accordance with the requirements of "urethane grade" ethyl acetate. Use the products of formal large companies, and do not easily use the products produced by informal enterprises, because the production control requirements of "urethane grade" ethyl acetate are very high, and it is difficult for informal enterprises to produce products that meet the requirements (i.e. high water content and alcohol substances).

4. Ink

(1) Misuse the ink, and use the surface printing ink as the internal printing ink. Before use, it is necessary to distinguish whether the ink to be used is used as surface printing or internal printing (i.e. composite printing).

(2) Ink and adhesive do not match (system). For aluminum plating composite, the drying effect can be properly controlled to maintain a certain flexibility of the adhesive film (that is, in the composite process, the adhesive film cannot be dried too thoroughly), and the curing agent can be appropriately reduced during the preparation of the adhesive liquid. Special gluing method (i.e. gluing on aluminized film) is a way to solve the low composite strength for aluminized composite.

075mm、0.1mm。

Specification: width 1000mm/1210mm, length can be determined according to customer requirements.

Color: transparent, blue, white and red are commonly used.

Glue system: silicone oil.