Application of release agent in automobile seat sponge production line

n 2017, China's automobile production and sales showed relatively rapid growth, with the total volume of production and sales reaching an all-time high, with 29.151.54 million vehicles and 28.8789 million vehicles completed respectively, an increase of 3.19% and 3.04% over the same period last year, respectively. Although the growth rate slowed down, the scale of new cars has been the first in the world for eight consecutive years.

Behind the new production and sales volume is also facing unprecedented fierce competition. Major automotive brands are flourishing, competing to launch a variety of new models, attracting the attention of consumers to compete for market share.

Different brands of new models correspond to the need to design and manufacture a variety of pre-formed parts, such as car seat sponge is one of them, it needs to be demoulded through a variety of different molds. With the increasingly stringent requirements of consumers on the performance of car seats, the seat sponge moulding of many models is becoming more and more complex. In the manufacture of sponge products, a suitable release agent can form an inert coating between the mould and sponge products, which can make the products easily remove from the mould, at the same time make the surface of sponge comfortable and qualified, and can effectively prolong the life of the mould.

At present, in the production line of automobile seat sponge, exterior coating release agent and organic solvent are commonly used as carriers. In terms of spraying methods, some large manufacturers have basically adopted electrostatic spraying, which will be introduced in the appropriate time in the future. This paper mainly introduces the application of externally coated solvent demoulding agent in automobile seat sponge production line through traditional air-jet method.

Main Components of 1 Demoulding Agent

Demoulding agent is a mixture of various substances through emulsification. Its main components are wax, siloxane, metal stearate, polyvinyl alcohol, fluorinated oligomers and polyolefins. Carriers are usually organic solvents or water to help the effective ingredients in the release agent distribute evenly on the required surface.

According to different requirements, the composition of release agent is also changed. The application of demoulding agent in moulding products has also undergone more than 20 years of evolution. Nowadays waxy component + organic solvent is the most commonly used type of release agent in the industry.

After spraying demoulding agent on the die surface, the actual interface of foaming forming is as follows:

In the figure above, the contact surface between foam and release agent is A, release agent is B, release agent and mould is C, release agent layer is condensation layer. When stripping, it is called interfacial stripping when stripping on A and C surfaces, while it is called condensate layer failure when stripping on B surfaces.

The release agent usually used requires stripping on B or A or B. The demoulding agent caused by the condensation layer has the best demoulding effect.

Classification of 2 release agents

There are many kinds of release agents, and the release agents used in different fields are different.

(1) According to the use method, there are external coating type, internal coating type, disposable, multiple, semi-permanent, concentrated (need dilution after use), ready-to-use (direct use).

(2) According to the classification of carriers, they are water-based and solvent-based.

(3) Classified by spraying method, there are traditional air spraying and electrostatic spraying.

(4) According to solid content, it can be classified as high solid, low solid, medium and high solid.

It is very important to select suitable release agent according to different pre-forming parts and production process conditions. At present, the traditional air-jet solvent release agent is commonly used in the production line of automobile seat sponge, which is usually called high resilience release agent or sponge release agent. The main components are microcrystalline wax, C9-C12 isoalkanes, etc. After release, the surface of the product needs to be dry and open, soft and comfortable, and easy to bond.

Application of 4 High Springback Demoulding Agent

Choosing the appropriate release agent is the key, but knowing how to apply the release agent properly and correctly plays a key role in maximizing the performance of release agent, reducing the waste of release agent, reducing the reject rate, and avoiding too short cleaning cycle caused by too fast accumulation of mould fouling.

4.1 Mould Cleaning and Maintenance

Due to the long-term use of demoulding agent, fouling will accumulate on the mould, which needs to be cleaned up in time. If the scale is not cleaned up, the release force of the release agent will increase, the consumption will increase, the product surface will be imprinted or the local die temperature will be too high or too low, which will cause the product to burn. At the same time, the mould needs to be maintained regularly.

Reasonable cleaning mode and proper maintenance can greatly prolong the service life of the die.

4.2 Mould maintenance before spraying

The mould maintenance before spraying is to ensure that the mould and the new demoulding agent are compatible. At normal operating temperature, 3 to 4 times of the same amount of release agent was applied to the die, and after each coating, it was confirmed that a complete film was formed on the surface of the die.

4.3 Molding Manufacture

After each pouring, it is necessary to clean the small pieces of foam stuck to the mold by air blowing. Then the upper and lower dies are uniformly sprayed with demoulding agent. Particular attention should be paid to the dead corner of the die. The spraying angle or short distance (2~3 cm) spraying should be adjusted. After spraying, blow dry with air gun.

The flow rate of spraying gun spraying products is controlled within an appropriate range. The caliber of the spray gun ranges from 0.5 mm to 1.2 mm.

Where the demoulding force is greater, the white wax can be repaired. The position of white wax coating is set between cleaning die and spraying release agent. For the viscous and tearing parts feedback by demoulding workers and cleaning workers, the amount of white wax should be controlled, less and uniform, and too much will cause serious defoaming of products.

4.4 Spraying Equipment

Air spraying is used for spraying demoulding agent on sponge production line. The traditional spraying method is to use 20 L or 40 L pressure vessel to connect spraying gun of suitable caliber, and to achieve the spraying atomization and flow rate by adjusting the pressure and pressure of the vessel. But because of the safety hidden in pressure vessel