Textile sizing PVA

CAS:9002-89-5

 Its molecular formula is[CH2CHOH]n,and the molecular formula for some of the PVA is -[CH2CHOH]n-[CH2CHOOCCH3]m-. PVA is non-toxic, insipid and harmless.

Textile sizing PVA is mainly used as a warp dressing agent, textile finishing agent and the raw material of vinylon, is now the most efficient synthetic sizing agent for warp paste with the following advantages: 

(1). Textile sizing PVA membrane has a good sizing effect and can improve the weavability of high-density and high-grade textiles due to its excellent properties of obdurability, smoothness, wear resistance and adhesiveness on fibers. 

(2). Textile sizing PVA has a powerful cohesive force on fibers as well as good protective effects to reduce times of textile yarn breaking and improve weaving efficiency. 

(3). Textile sizing PVA size paste doesn’t not get corrosive easily and degraded without any change in viscosity after long-time heating, which ensures stable sizing and minimizes hard size spots. 

(4). At textile factories the moisture of starch paste must be at 80-85%, while the moisture requirement for PVA size mixture is just 70-75%, which makes it possible to improve operating environment and production efficiency. 

(5). To minimize desizing in the process of sizing and weaving and keep the factory area clean, PVA series with medium degrees of polymerization and 90-97 (mol/mol)% alcoholysis, such as 20-95 and 17-95, are applicable.

Storage 

Textile sizing PVA can be storaged for a long period without denaturalization unless it contacts water directly. During the storage, volatilization matter may slightly cause both moisture and weight loss but that will not affect the quality of PVA. Then, when the volatilization matter gets low, PVA absorbs easily moisture and adds weight to it. 

If it is not contaminated, PVA solution does not rot or deteriorate easily which makes it easier for storage than any other macromolecular solution.

PVA 24-99, 18-99, 17-99 13-99 series are high viscosity and complete alcoholysis types. If they are made into a paste with a concentration higher than 8%, they can be stored at the ambient temperature lower than 20℃ with increased viscosity, forming gel due to molecule crystallization without any change in nature. Their fluidity can be restored to the original after heated and stirred. To avoid such happenings, in winter the frost resistance type PVA can be selected, or similar products with alcoholysis degrees of 88-97(mol/mol)%, which perform slightly poor in PVA water resistance, or by combination of complete and partial alcoholysis types for freeze resistance.

For the PVA with a degree of alcoholysis smaller than 99 (mol/mol)%, its viscosity is consistent with few possibilities to gel at low temperatures.

Stainless steel tanks are suitable for storage of PVA paste. If only iron or carbon steel containers are available, 0.05% sodium nitrate or sodium benzoate can be added into the PVA paste to avoid rusting.

Given a long period of storage, the untreated PVA solution in water mildew and rot easily, when some 0.01%-0.05% antiseptic can be added, e.g. salicylic acid