Factors affecting the breathability and moisture permeability of composite fabrics

Factors affecting the breathability and moisture permeability ofcomposite fabrics

Oxford cloth for bags

Composite fabric
Composite fabric is a new type of material formed by bonding one or more layers of textile materials, non-woven materials and other functional materials. Suitable for sofas, clothing and other textiles, it is one of the indispensable fabrics for people’s home life. Composite fabric is made of microfiber through specific textile processing and unique dyeing and finishing, and then processed by “composite” equipment. The English name of composite fabric is: “Lamination Fabric” and “Soft Shell Fabric”. Because the composite fabric uses microfiber, the fabric has high cleaning ability, that is, decontamination ability.

Summary: It is a new type of fabric made of one or more layers of textile materials laminated by oil glue or hot melt glue.
6 internationally popular composite fabric techniques
1. Hot sol powder dot coating composite fabric technology
2. Hot melt glue dot composite fabric technology★ namely PUR
3. Hot melt powdered composite fabric technology
4. Hot melt double-point composite fabric technology
5. Polyurethane spraying composite fabric technology
6. Polyurethane roller coating composite fabric technology ★ namely PU

Cotton flame retardant, fireproof and high temperature resistant twill yarn card.jpg

Divided according to the number of layers:

Three layers: lamination with film (called three-in-one composite on the market);
Second layer: composite without film

Production principle

The core components of composite equipment are the gluing device and the composite device. When the surface cloth (film) passes through the gluing device, it is squeezed by the gluing pressure roller. The glue in the glue eyes of the engraving roller is forced to transfer to the surface cloth (film), and then is pressed by the composite device to obtain the initial bonding. Fastness.
Gluing device

For an engraving roller and a rubberized silicone pressure roller.
There are two general point shapes of engraving rollers: diamond points and round points.
The diamond-shaped points are arranged regularly, the points are consistent, and the water pressure resistance is relatively good. There are two types of circular dots: regular arrangement and irregular arrangement. The dot spacing is inconsistent and the water pressure resistance is relatively weak.

Maintenance treatment

The time of maintenance processing has a great influence on the fastness of fabric bonding and the degree of fusion of adhesive. The maintenance processing workshop is fully enclosed and a certain temperature and humidity are maintained indoors to allow the adhesive to fuse naturally. If it is added in order to complete it quickly, At high temperatures, during the sewing process of fabrics, the yarns are easily broken by needles and become hard to the touch. There will be a rustling sound when rubbing against each other, indicating that the adhesive has solidified on the fabric and hardened the yarns of the fabric.

PU process equipment
In traditional compounding equipment, the original glue is heated and dissolved in the solvent, the glue solution is added to the glue application tank manually, and the solvent is evaporated by hot pressure in the compounding wheel.

The maturation conditions of the glue solution are 30℃×5day, so that the solvent can evaporate to the maximum extent.

Advantages and disadvantages of PU process:

advantage

1. Low cost, flexible and convenient operation

shortcoming

1. The solvent is pungent and not environmentally friendly, and can easily produce APEO and formaldehyde
2. Impurities are easily mixed in when applied manually, and the amount of glue applied to the glue points is unstable
3. If more glue is applied, the feel will be harder.
4. Ready-made garments cannot be dry cleaned.

★This process has many problems. If it is not a chemical fiber fabric, it is recommended not to use this process.

PUR process equipment

Use 100% solid content single-component reactive hot melt adhesive, which does not contain chemical solvents, is environmentally friendly and has no irritating odor. The machine is automatically applied and the glue tank is heated.

The maturation conditions of hot melt adhesive are 30℃ room temperature, humidity >90%, and it must be left for 72 hours to achieve the final peeling effect.
</pIncrease, capillary moisture permeability becomes the main factor.

4. Fabric finishing
Fabric finishing such as coating or impregnation can increase the moisture resistance of the fabric. Because it increases the path of water vapor through the fabric or blocks the gaps in the fabric. However, hydrophilic finishing will increase the moisture permeability of the fabric. Water-repellent finishing generally does not affect the moisture permeability of fabrics.

5. Other factors
Generally, the liquid water transmission speed of the fabric is greater than the evaporation rate of the liquid surface. There are smaller gaps and holes on the inside of the fabric, which makes it easy to condense into liquid water and transport it outward, forming a differential capillary effect. There are larger gaps and holes on the outside, which makes it easy to meet the evaporation conditions. , helpful for dispersing dampness. The evaporation capacity of liquid water on the surface of the fabric is not closely related to the fabric thickness, porosity, etc., but is closely related to the uneven shape of the fabric surface, especially the size and depth of the surface pits. In general, the larger the pit opening area, The larger the radius of curvature, the higher the evaporation efficiency. The details of the pits, wind speed, temperature differences, etc. also have obvious effects.