Cellulose ether is a non-ionic semi-synthetic polymer, water-soluble and solvent two, in different industries caused by the role is different, such as in the chemical building materials, it has the following compound effect:
① water retaining agent, ② thickening agent, ③ leveling, ④ film forming, ⑤ binder
In the PVC industry
it is an emulsifier, dispersant;
In the pharmaceutical excipient industry
it is a kind of binder and slow release skeleton material, because cellulose ether has a variety of composite effects, so it is the most widely used field. Below I focus on the use of cellulose ether in a variety of building materials and the role.
In latex paint
In the latex paint line, to choose hydroxyethyl cellulose, the general specification of equal viscosity is 3000-50000cps, it corresponds to HBR250 specifications, the reference dosage is generally 1.5‰-2‰. The main role of hydroxyethyl cellulose in latex paint is to thicken, prevent pigment gelation, contribute to the dispersion of pigment, latex, stability, and can improve the viscosity of components, contribute to the leveling performance of construction: Hydroxyethyl cellulose is easy to use, both cold and hot water can be dissolved, and is not affected by PH value. It can be safely used between PI value 2 and 12. The methods of use are as follows:
I. Add directly in production
For this method, delayed hydroxyethyl cellulose with a dissolution time of more than 30 minutes should be selected. The procedure is as follows: (1) to have high should cut blender container quantitative pure water (2) the internal force of people began to low-speed mixing, hydroxyethyl uniform slowly at the same time to join in the solution of (3) continue to stir until all wet granular materials (4) to join other additives and alkaline additives (5) stir until completely dissolved all hydroxyethyl, add the other components of formula, grinding to the finished product.
2, equipped with mother liquor
This method can choose the fast – soluble cellulose, and has mildew – proof effect. The advantage of this method is to have bigger flexibility, can join emulsioni paint directly in, make up a method is same as ①–④ step is same.
3, with porridge for use
Since organic solvents are poor solvents (insoluble) for hydroxyethyl, they can be used to prepare porridge. The most commonly used organic solvents are the organic liquids in latex paint formulations, such as ethylene glycol, propylene glycol and film forming agents (such as diethylene glycol butyl acetate), the porridge hydroxyethyl cellulose can be directly added to the paint, after adding, continue to stir until completely dissolved.
In the scraping wall putty
At present, China is in most of the city water resistance, resistance to swab of environmental protection putty has been basically taken seriously by people, in a few years ago, because the putty made of building glue radiates formaldehyde gas damage to people’s health, building glue is made of polyvinyl alcohol and formaldehyde acetal reaction. So this material is gradually eliminated by people, and the replacement of this material is cellulose ether series of products, that is to say, the development of environmental protection building materials, cellulose is the only kind of material at present.
In water resistance putty is divided into dry powder putty and putty paste two kinds, these two kinds of putty generally choose methyl cellulose and hydroxypropyl methyl two kinds, viscosity specification is generally in 40,000-75000cps between the most appropriate, in the main role of cellulose in putty is water retention, bonding, lubrication and other effects.
Because the putty formula of each manufacturer is not the same, some are gray calcium, light calcium, white cement, some are gypsum powder, gray calcium, light calcium, etc., so the specification viscosity and infiltration amount of cellulose of the two formulas are not the same, the general amount of adding is 2‰-3‰ or so.