Nov. 10, 2021
Hot-rolled bonding and hot-air bonding are the two main processing methods of nonwoven thermal bonding reinforcement. Hot-rolled bonding is a thermal bonding method in which a pair of hot rollers is used to heat the web and apply a certain amount of pressure to it, while hot-air bonding is a production method in which hot air is used to penetrate the web and melt it in the drying equipment to create a bond.
WEIJIA introduces you to the different performance and style of the two types of products.
In the production of hot air bonding, a certain percentage of low melting point bonding fiber is mixed into the web or a two-component fiber is used, or a powder spreading device applies a certain amount of bonding powder to the web before it enters the drying room. The powder melting point is lower than the melting point of fibers, and melts quickly after heating, so that the fibers are bonded to each other.
The heating temperature of hot air bonding is generally lower than the melting point of the main fibers. The strength of the bonded fiber is lower than the normal fiber, therefore, the amount added should not be too large, generally controlled at 15% to 50%. Bicomponent fibers are very suitable for use alone or as bonding fibers in the production of hot air bonded nonwovens due to their small thermal shrinkage, forming a point bonding structure with good results, and the products produced by this method have a high strength and a soft feel.
With its unique style, hot air bonded products are widely used in the manufacture of disposable products, such as baby diapers, adult incontinence pads, fabrics for feminine hygiene products, as well as napkins, bath towels, disposable tablecloths, etc.; thick products are used to make cold-weather clothing, bedding, baby sleeping bags, mattresses, sofa cushions, etc. High-density hot melt bonded products can be used for filtering materials and nonvowen masks, sound insulation materials, shock absorbing materials, etc.
Since cotton, wool, hemp, viscose and other fibers do not have thermoplastic properties, these fibers alone cannot be reinforced with hot bonding. However, a small amount of cotton, wool and other fibers can be added to the thermoplastic fiber network, which can improve some of the properties of nonwoven fabrics, but generally should not exceed 50%. For example, cotton / polyester to 30 / 70 mixed ratio made of hot-rolled bonded nonwoven, can significantly improve the moisture absorption, feel and softness, and is very suitable for doing with medical and health supplies. The strength of the nonwoven decreases as the cotton fiber content increases. Of course, for fiber webs consisting entirely of non-thermoplastic fibers, the reinforcement can also be considered using the powder-spreading hot bonding method.
In addition, thermal bonding is also commonly used with the production of composite nonwovens (e.g. melt-laminated nonwovens) or as a complementary means to other reinforcement methods. For example, mixing a small amount of low melting point fibers in the fiber web, needling reinforcement and then hot air bonding can significantly improve the strength and dimensional stability of the needled product.
Hot-rolled bonded products have high yield, low cost, high hygiene, high strength, flat density, etc. They are widely used in the manufacture of medical and health products, such as surgical gowns, masks, women's sanitary napkins, and various protective clothing and work wear. It is also used in agricultural harvest cloth, geotextile, electric insulation cloth, battery diaphragm, packaging material, artificial leather base cloth, waterproof material base cloth, etc.
Please contact our experts to get our nonwoven products!
