Application of the hottest melt adhesive coating t

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Application of hot melt adhesive coating technology

I. Introduction hot melt adhesive coating is a green and environment-friendly coating and packaging technology. At present, although the development history of domestic hot melt adhesive coating process has been more than ten years, the manufacturing technology of hot melt adhesive coater is still in an immature stage in China. Many printing and packaging machinery manufacturers have participated in the production of hot melt adhesive coater from 2400 exhibitors in 2011, and the main quality problems have not been well solved

hot melt adhesive, as its name suggests, is an adhesive that becomes molten after heating and binds various materials together after coating. Compared with other adhesives, hot melt adhesives have the following characteristics: 100% solid composition, without solvent and water components; It has thermal plasticity, that is, it can be heated, melted and cooled repeatedly. This process is reversible, and the chemical and physical properties of the hot melt adhesive will not be changed; The hot melt adhesive can be coated only when it is heated into a molten state; The adhesive force is produced by the cooling and solidification of the hot melt adhesive

Since its advent, hot melt adhesive has been widely used in food packaging, book binding, disposable sanitary products industry, furniture industry, label industry and other fields because of its high bonding strength and fast curing speed

II. New technology and development trend of hot melt adhesive industry

1 Low temperature hot melt adhesive

low temperature hot melt adhesive breaks through the use limit of general traditional hot melt adhesive. Its normal operating temperature is only 110 ℃ ~130 ℃, and the service temperature of low-temperature hot-melt adhesive is more than 30 ℃ lower than that of traditional hot-melt adhesive. Compared with traditional hot melt adhesives, low-temperature hot melt adhesives have significantly lower viscosity, ensuring that they meet the requirements of various coating processes under low-temperature operating conditions

the direct benefit of low-temperature hot melt adhesive is to save electricity and machine maintenance costs. A large number of practical applications show that using the same hot melt adhesive machine with low temperature hot melt adhesive can save customers about 15% of electricity. Since the low-temperature hot melt adhesive has almost no aging phenomena such as scaling and carbon deposition at its normal operating temperature of 110 ℃ ~130 ℃, the maintenance cost of the machine is greatly reduced. More importantly, low-temperature hot melt adhesive will not burn PE film

2 Hydrophilic hot melt adhesive

traditional hot melt adhesive is generally hydrophobic. Hydrophilic hot melt adhesive makes it hydrophilic through special formula. The application of each hydrophilic hot melt adhesive can give products higher added value, so that product manufacturers can effectively differentiate products in the current highly competitive market, so as to finally win consumers

3. Other new technologies of hot melt adhesive

in addition to the above aspects, new technologies of hot melt adhesive also include: oil resistant hot melt adhesive; Hot melt adhesive suitable for high-frequency spraying; "This revolutionary new product shows the value of an integrated material solution that combines comfort, durability and aesthetics for important product innovation. High wet strength hot melt adhesive; degradable hot melt adhesive, etc.

III. classification of melt coating technology

1. Scraping system

during the coating process, the glue is often uneven, which requires a certain scraping mechanism to scrape the glue evenly. The scraping mechanism mainly includes stainless steel Sheet 296 mineral wool and its products for thermal insulation scraper, comma scraper, scraper rod, steel wire scraper, pneumatic scraper, etc

2. Grain coating

this coating equipment mainly uses grain coating rollers to apply glue. The coating is uniform and the coating amount is relatively accurate. However, once the type of coating roller and glue is determined, it is difficult to adjust its coating amount, which is also the main reason why the application of coating roller is limited

3. Calendering coating

this method uses a calender to coat the rubber on the surface of paper or fabric substrate, including film calendering coating and powder calendering coating. The former is that after the coating plastic is made into a film, it is heated and fused by the calendering roller and bonded to the surface of the substrate; The latter is to spray the powdered resin on the surface of the substrate, and then heat it by the calendering roll to melt and stick it together

4. Spraying system

this coating equipment mainly heats and melts the solid glue, and then the glue is directly sprayed on the substrate through the coating die by the hydraulic device

IV. scratch free coating technology

in 2007, according to the market demand, we began to invest in the research and development of hot melt adhesive coating equipment technology for thin film materials. The new scratch free hot melt adhesive coating head came out. The equipment has the following characteristics:

scratch free effect, especially suitable for coating and compounding of pet, PVC, OPP and other materials; The minimum gram weight can reach 15g/㎡, and the running speed can reach 180m/min; With a high degree of automation, the PLC control mode is adopted, and a variety of functions and operations are gathered in the man-machine interface to ensure that the operator can easily control the equipment

the successful research and development of this device fills the technological gap in this field in China and is the first in China. It solves the situation that the hot melt adhesive coating and UV curing hot melt adhesive coating of pet, PVC, OPP and other materials rely on imported equipment, and saves a lot of capital investment for the upgrading of products in the industry

in recent years, foreign countries have successively developed a new generation of green and environmentally friendly hot melt adhesives, such as biodegradable and water dispersible adhesives. Because this kind of improved adhesive is different from traditional thermosetting and solvent-based adhesives, it does not contain any solvent. The zigzag tester of Jinan new era Gold Testing Instrument Co., Ltd. is mainly used for repeated zigzag experiments of metal wires, and will not pollute the environment due to solvent volatilization. Therefore, the new environmental friendly hot-melt adhesive has attracted more and more attention from insiders and favored by the market

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