Microporous coating waterproof and breathable coating technology

Microporous coating waterproof and breathable coating technology
The coating process is different due to different moisture permeability methods and different coating application methods. I will not go into details here, but only introduce the waterproof and moisture-permeable process of dry direct coating of microporous coating agents.
(1) Waterproof and moisture-permeable coating process
The large-scale production process of DicrylanPC microporous acrylate water-dispersed coating agent from Swiss Ciba-Geigy Company and domestic PP-3 microporous acrylate water-dispersed coating agent, which are applied by floating scraper type, is introduced as follows:
1. DicrylanPC
(1) Fabric T/C05/35gIcm60/2×60/2120×70 polyester-cotton poplin.

(2) Process flow Fabric pre-treatment – coating finishing – waterproof finishing – finished product.

(3) Process prescription
I) Pretreatment formula KnittexLE thermosetting resin 20 grams Kn~ttexZ0 catalyst 4 grams 80% acetic acid 2 grams PhobotoneWS waterproofing agent 60 grams PhobotonezF catalyst l2 grams/liter
2) Coating finishing formula D~crylanPC coating Jing 100kg Kn~ttexLE 5kg perchlorethylene or ethyl acetate. 10kg DicrylanO thickener/ethanol (1:)Xkg
3) The waterproof finishing formula is the same as the pre-treatment formula
2. PP-3 microporous coating agent
(1) Pre-treatment formula AG-710 waterproofing agent 70g/L
(2) Coating finishing formula pp-3l00 ml ammonia thickened to working viscosity
(3) The waterproof finishing formula is the same as the pre-treatment formula gtJtM12_4h~2g ship. 55B9B is about double that of similar products from Ciba-Geigy Company in Switzerland. However, the water pressure resistance is not as high as that of Ciba-Geigy, and the difference is also quite large·
(3) Factors affecting impermeability water pressure and moisture content
There is a contradiction between the impermeable water pressure and the moisture permeability. If the impermeable water pressure is high, the moisture permeability will be reduced. On the contrary, if the impermeable water pressure is low, the moisture permeability will be increased. To handle this contradiction well, in addition to the quality of the microporous coating agent itself, it also involves the application method. Process formula and process operation factors.
1. Working viscosity
The working viscosity of microporous coating agents is important. It affects the water pressure resistance and moisture vapor transmission rate. Low viscosity means large micropores, more general porosity, poor film-forming properties, good moisture permeability, and poor anti-penetration water pressure; sticky

The higher the degree, the smaller the pore size, less microporosity, and good rheology, so the film-forming performance is good, the water pressure resistance is good, and the moisture permeability is poor. Therefore, it is necessary to properly control the rubidium in the working cliff to obtain ideal anti-seepage water pressure and moisture permeability.

2. Effect of coating amount
Generally speaking, if the coating amount is high, the water resistance will be high, the moisture permeability will be low, and the hand cancer will be harder. The coating amount will decrease as the viscosity increases. But when the viscosity is too high. Rheology becomes worse. The coating amount increases instead; when the viscosity is low, the coating amount should also be increased. Therefore, in order to balance the relationship between impermeability water pressure and moisture permeability, it is not only necessary to control the coating amount, but also to handle the relationship between coating amount and viscosity. The coating amount is also related to the shape, sharpness and speed of the scraper.
3. The influence of the method of application
The coating amount control of different application methods is different, which also affects the anti-penetration water pressure and moisture permeability. The floating scraper is finer and the coating amount can be very low. In order to increase the coating amount, a relatively slow scraper should be used; the roller scraper has a high coating amount and a sharper blade should be used; the garden net is more suitable for waterproof and moisture-permeable coatings In short, the application method of dry direct waterproof and moisture-permeable coating process must comprehensively consider various factors and cannot be carried out alone, otherwise it will cause one thing to be lost and the internal relationship between impermeability water pressure and moisture permeability cannot be properly established.
1. There are many kinds of waterproof and moisture-permeable coatings. The process described here only refers to the dry direct waterproof and moisture-permeable coating of microporous coating agent. The data provided are actual production samples tested. In particular, the factors that affect the quality of waterproof and breathable coating products are also targeted at this aspect.
2. Waterproof and moisture-permeable coating products are popular mid- to high-end products in the international market, with high added value and promising development prospects.
3. At present, there are only microporous acrylic coating agents in China, which are used in the development of waterproof and moisture-permeable coating products. Although microporous polyurethane coating agents are available. However, it is not ideal in terms of water pressure resistance, moisture permeability and hand feel, and needs further improvement.
4. The development of coated fabrics results from the combination of textile base fabrics, highly specialized polymer chemistry and modern coating technology. Waterproof and moisture-permeable coating technology and product development are being vigorously studied abroad. fast development. Although there are currently flame fusion methods, hot pressing methods, glue compound methods and wet coatings in China, further development of polytetrafluoroethylene and polyurethane is needed

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