factors affecting the quality of tpu waterproof and breathable membrane

some customers called and said that the quality of tpu waterproof and breathable membranes purchased online was uneven. they did not dare to place an order without buying samples. so today i will talk to you about the reasons that affect the quality of tpu waterproof and breathable membranes.

1. tpu raw materials. raw materials are the main factor affecting waterproofing and moisture permeability. most tpu products on the market are not waterproof and moisture permeable products. even if some films can be made, their air permeability and moisture permeability are very low, and they are often called air-locking films. the amount of hygroscopic components in tpu will have a greater impact on moisture permeability, which has a great relationship with the formula during tpu synthesis.

2. film thickness. film thickness has a great influence on moisture permeability, but the thickness of the product is not directly proportional to the moisture permeability. the same raw materials and additives are used to produce medium-permeable membranes with different thicknesses on the market. the typical values ​​of moisture permeability tested according to the astm e96 bw-2010 version will be different.

3. additives. during the production process of tpu, due to its high viscosity, it is usually necessary to add various anti-adhesive additives; in order to produce film products of different colors, some additives such as color masterbatches need to be added, and these additives usually do not themselves have waterproof and moisture permeable performance, after adding, the moisture permeability of the finished film will be more or less reduced; it is best to use waterproof and moisture permeable tpu materials as the carrier of this type of additive, which can reduce the impact on moisture permeability.

4. hot melt glue. when fabric and film are combined, the area occupied by hot melt adhesive per unit area will have a great impact on the moisture permeability of the combined product. the impact on moisture permeability can be reduced by reducing the weight of glue applied during lamination, reducing the area of ​​glue points per unit area, replacing moisture-permeable hot-melt adhesives, and using spot-glued lamination.

at present, there are many manufacturers of tpu films in china, and most of them are processed by casting and film blowing. if you consult more when purchasing, you can reduce some problems.