Chemical spray-bonded wadding currently occupies a significant share of the thermal insulation cotton filling market, especially the imitation silk cotton derived from chemical spray-bonded wadding, which is popular among many garment manufacturers. So, what is chemical spray-bonded wadding, what equipment is needed for a chemical spray-bonded wadding production line, and how can the quality of chemical spray-bonded wadding be ensured?
1. What is Chemical spray-bonded Wadding?
Chemical spray-bonded wadding is made by spraying adhesive onto both sides of a fluffy fiber layer. Due to the pressure applied during spraying, the adhesive also penetrates into the interior of the fiber layer. After drying and curing, the fiber junctions are bonded together, forming a wadding with a certain thickness and strength. The fibers that are not bonded together still have considerable freedom of movement, and there are many air-filled voids in the three-dimensional network structure. Therefore, chemical spray-bonded wadding has the characteristics of porosity and high fluffiness. Its varieties are often distinguished by fluffiness and softness, and can generally be divided into ordinary chemical spray-bonded wadding, soft cotton, and loose cotton products.
Compared with traditional wadding materials, chemical spray-bonded wadding has more than 30% higher fluffiness than cotton wadding; at the same thickness, its air content is 40-50% higher than cotton wadding, and it has good thermal insulation and breathability.
2. Chemical spray-bonded wadding Production Line Process
According to the process from raw materials to finished product, a typical chemical spray-bonded wadding production line requires the following steps:
Opening machine → Blending machine → Feeding machine → Carding machine → Cross lapper → Three-layer spray bonding oven → Flat Ironing machine → Edge trimming → Winding and Cutting machine
3. Factors Affecting the Quality of chemical spray-bonded wadding
Many factors affect the quality of chemical spray-bonded wadding, but the decisive factors are mainly the selection of fiber raw materials, adhesives, and fiber web structure parameters.
3.1 Influence of Fiber Raw Materials on Product Properties
Chemical fibers are the main raw materials for chemical spray-bonded waddings, generally using polyester fibers. They form the structure and framework of the chemical spray-bonded wadding, accounting for 80-95% of the finished product's weight. From raw fiber to finished product, the fiber characteristics do not change significantly; therefore, the performance of the fiber determines the quality of the chemical spray-bonded wadding. Its influence on the chemical spray-bonded wadding can be discussed from both physical and chemical properties.
3.1.1 Influence of Fiber Physical Properties
The main technical indicators required for fibers in the production of chemical spray-bonded wadding are crimp, elasticity, and denier, all of which affect the chemical spray-bonded wadding.
3.1.2 Influence of Fiber Chemical Structure
Different fibers have different chemical structures, which determine their basic properties. For example, viscose and cotton fibers have hydrophilic groups in their molecular structure, resulting in good moisture absorption, while chemical fibers have poorer moisture absorption. Therefore, adding a certain amount of viscose or cotton fibers to the raw materials when producing chemical spray-bonded nonwoven batting can greatly improve the product's moisture absorption and compensate for the shortcomings of synthetic fibers.
3.1.3 Influence of Different Fiber Raw Material Mixing Ratios
When selecting raw materials, it is essential to understand the fiber characteristics and their impact on the performance of the resulting product. The selection should be based on the product's intended use, while also considering cost factors, production processes, and equipment conditions.
3.2 Influence of Adhesives on Product Properties
Adhesives are used to reinforce the fiber web. They transform the uniform fiber web into a fluffy material with a certain dry and wet strength, not only meeting the strength requirements of the fluffy material for processing and use, but also, with proper selection and application of the adhesive, imparting superior properties to the chemical spray-bonded wadding compared to the original fibers. Although the adhesive only accounts for 5-15% of the finished product's weight, its thin film characteristics directly affect the feel, elasticity, and washability of the finished product because it is distributed on the fiber surface.
The adhesive's reactive monomers and additives, the glass transition temperature of the adhesive, the type, specifications, and number of nozzles, as well as the nozzle's movement method, installation height, and pressure, all directly affect the chemical spray-bonded wadding product. The amount of adhesive in the chemical spray-bonded wadding is a key factor affecting the product's style and feel.
3.2.1 Influence of Solid Content on Product Strength
As the solid content of the adhesive increases, the tensile strength, tear strength, and bursting strength of the product all increase. This is because the adhesive is sprayed onto the fluffy fibers, causing bonding between the fibers, forming many bonding areas distributed between the fibers. When the solid content of the chemical spray-bonded wadding increases, the opportunities for bonding increase, the bonding areas increase, and the bonding strength between fibers increases, thus increasing the product's strength. The transverse strength of the chemical spray-bonded wadding is greater than the longitudinal strength. This is mainly because the fibers have directionality in mechanical web laying, and although they are randomly formed into a web, the transverse strength is still 1-2 times greater than the longitudinal strength.
3.2.2 Influence of Solid Content on Air Permeability and Thermal Insulation
As the solid content of the adhesive increases, the air permeability of the product decreases, and the thermal insulation increases. Because an increase in solid content means a higher adhesive content, it hinders the airflow between the fibers, making the air between the fiber layers more stable, thus reducing air permeability and increasing thermal insulation.
3.3 The Influence of Fiber Web Structure on Product Quality
The fiber web structure mainly refers to the distribution pattern of the fibers. For example, mechanically formed fiber webs are composed of layered fiber webs, with most fibers exhibiting directional distribution; in airlaid nonwovens, the fibers fall freely due to airflow, resulting in a high degree of randomness and a random distribution.
4. Market Prospects of chemical spray-bonded wadding
The traditional bedding and garment processing industries typically use cotton, silk cotton, and down as intermediate filling materials. Due to resource limitations, the price of natural fiber raw materials is constantly rising. At the same time, with the continuous improvement of people's consumption levels, some inherent drawbacks of these natural materials, such as easy compaction and lack of durability, also affect their application performance. my country began producing chemical spray-bonded wadding in the mid-1980s. This process involves carding, web formation, and bonding of chemical fibers to create a batting that replaces traditional cotton batting. This not only reduces the amount of cotton used but also significantly improves performance. Based on this, imitation silk cotton products have been developed, representing a new generation of chemical spray-bonded wadding products with very promising market prospects.
