1. Introduction of raw materials
TPU hot melt adhesive is a solvent-free new environmental protection material, the formula is based on polyurethane framework for various characteristics design, at room temperature is a solid, when heated above the melting point will melt into a viscous liquid, laminating processing, cooling to room temperature and then become solid, is a reversible thermoplastic material, with good elasticity, flexibility and low temperature flexing characteristics, for a variety of different materials with a strong bonding effect. TPU Hot melt adhesive film is widely used in clothing, shoes, bags, handbags, garments, medical, military, toys, shoe fabric lamination, silicone breast pads, underwear accessories, waterproof zippers, trademark lamination, computer 3C supplies, water-filled bags, inflatable bags, foam laminated products.
Because it does not contain solvents and is 100% solid, there is no risk of flammability or explosion during processing and delivery. In addition, it has the following advantages:
(1) fast curing speed, cooling that curing, high production speed, save equipment space.
(2) Bonding process is simple, less waste, there is no mixing of ingredients.
(3) Easy bonding process, less waste, no mixed ingredients problem.
(4)Wide range of substrates can be bonded, and automatic processing is possible.
(5) Excellent chemical and physical properties, with high adhesive strength and flexibility.
(6) No organic solvent, no VOC pollution problem.
(7) Environmentally friendly materials, waste can be naturally degraded.
2. Processing methods
The use of the way divided into film, grinding powder, and dissolution processing. Production of TPU hot melt adhesive film is generally used T-die extrusion processing, thickness control in 0.05 ~ 0.3mm, production will be equipped with Taiwan release paper or the use of high and low temperature double-layer structure, downstream users to use easy to operate, just put the hot melt adhesive film in two layers of fabric to be adhered, through the iron or hot press pressure can be laminated. The grinding process is to use an ultra-low temperature environment to lower the material to below the glass conversion temperature before grinding, downstream processing can sprinkle the powder on the fabric, with hot pressing or infrared heating for lamination. Dissolution processing is to dissolve the hot melt adhesive in specific solvents, such as butanone, acetone, toluene, and other solvents, customers can combine the existing solvent glue processing method because ITPU hot melt adhesive has high safety and stability, for cross-border transactions and delivery is very important, in the footwear industry and textile lamination is widely used.
3. TPU hot melt adhesive applications
1) Water stop tape application, also known as heat sealing tape and water stop strip
The composition of the tape can be single-layer or multi-layer film composition, the use of heat sealing tape lamination processing textile fabric sewing line, in order to prevent water leakage. The products are mainly used for waterproof clothing, underwear, outdoor clothing, mountaineering clothing, fishing clothing, raincoats, army field uniforms, medical dustproof clothing, anti-permeable blood pads, camping tents, police uniforms, down jackets, sportswear, leisurewear, and other waterproof products. Recently, due to the rise of functional clothing, boasting a good sense of skin contact and good resilience, the characteristics of hot melt adhesives are becoming more and more demanding, including high strength of low-temperature lamination, good fabric permeability, hydrolysis resistance, fast crystallization speed, mulberry soft, UV resistance and other functions.
2) Functional film
TPU hot melt adhesive film is used in apparel, mainly to paste two layers of fabric, in the functional clothing will be set because of the demand (feel, resilience, fog, transparency, etc.) to set the material characteristics, another need to examine for the type of laminated material, such as foam, PVC, Nylon, EVA, polyester, cotton, Lycra, etc., the film settings will be different, the choice of many professional investigations, this part of the product often needs to be matched with the customer for project development. In recent years, there has been significant progress in the application of shoe materials. Through the introduction of TPU hot melt adhesive film in product design, sports shoes have developed products without stitching, which has significantly reduced labor costs and weight, and many shoe manufacturers have adopted this method to produce high-performance shoes.
3) Glue for shoes
TPU hot melt adhesive is dissolved in solvents such as butanone or acetone, sometimes mixed with toluene, the solid component is usually set at 15%, widely used in shoe materials or fabric lamination, commonly used viscosity at 25 ℃ between 1600 ~ 5000cps, such applications need to consider the initial bonding strength, heat resistance, sticky time and other characteristics.
