The use and role of cellulose ether in various building materials

Cellulose ether is a kind of non-ionic semi-synthetic polymer with water-soluble and solvent-soluble, which causes different roles in different industries, for example, in chemical building materials, it has the following compound roles:

① water retaining agent ② thickener ③ leveling ④ film forming ⑤ binder

In the PVC industry, it is an emulsifier, dispersant; in the pharmaceutical industry, it is a binder and slow and controlled release skeleton materials, etc. It is precisely because cellulose has a variety of composite roles that it has the widest range of applications. The following focuses on the use and role of cellulose ether in various building materials.

(1) In wall putty:

At present, our country in most cities water-resistant, scrub-resistant environmentally friendly putty has been basically valued by people, in the first few years, due to the use of construction glue made of putty radiating formaldehyde gas damage to people's health, construction glue is made of polyvinyl alcohol and formaldehyde acetal reaction. So this material is gradually eliminated by the people, and replace this material is cellulose ether series products, that is to say, the development of environmentally friendly building materials, cellulose is currently the only one material.

In the water-resistant putty is divided into dry powder putty and putty paste two kinds of putty, these two kinds of putty generally to choose modified methyl cellulose and hydroxypropyl methyl two kinds of viscosity specifications generally in 30000-60000cps between the most suitable, in the putty cellulose's main role is to retain water, bonding, lubrication and other roles. Because of the various manufacturers of putty formula is not the same, some are gray calcium, light calcium, white cement, etc., some are gypsum powder, gray calcium, light calcium, etc., so the two formulas to choose the specifications of cellulose viscosity and its infiltration of the amount is not the same, the amount of general accession of 2 ‰ -3 ‰ or so. In scraping wall putty construction, due to the wall substrate have a certain degree of water absorption (brick wall water absorption rate of 13%, concrete for 3-5%), coupled with the outside world of evaporation, so if the putty loses water too quickly, it will lead to cracks or de-powdering and other phenomena, thus weakening the strength of the putty, for this reason, after adding cellulose ether will solve this problem. But the quality of the filler, especially the quality of gray calcium is also extremely important.

Because cellulose has a high viscosity, thus also enhance the putty's adhesion, but also to avoid the construction of the phenomenon of hanging, and scrape up after the more comfortable, labor-saving and so on. In the dry powder putty cellulose ether should be appropriate to add more points, its production, use are more convenient, filler and additives for dry powder uniform mix can be, construction is also more convenient, on-site water, with how much with how much.

(2) concrete mortar:

In the concrete mortar, really reach the final strength, must make the cement completely hydration reaction only, especially in the summer construction, concrete mortar water loss too fast, take measures to fully hydrate on the conservation of sprinkler, this method is a waste of water resources and inconvenience of operation, the key is that the water is only on the surface, and the internal hydration is still incomplete, so the solution to the problem of the method of joining in the mortar concrete Water retention agent cellulose generally choose hydroxypropyl methyl or methyl cellulose, viscosity specifications between 20000 - 60000cps, add 2% - 3%. Around, the water retention rate can be increased to more than 85%, the use of mortar concrete in the method of dry powder evenly mixed into the water can be.

(3) in stucco plaster, bonding plaster, embedded plaster:

With the rapid development of the construction industry, people's demand for new building materials is also increasing. Due to the increase in people's awareness of environmental protection and the continuous improvement of construction efficiency, the cementitious material gypsum products have been developed rapidly. At present, the most common gypsum products are brushing plaster, bonding plaster, embedded plaster, tile adhesive and so on. Brush plaster is a kind of excellent quality plastering material for inner wall and top board, with which the wall surface is delicate and smooth, no powder falling off and the substrate is firmly bonded without cracking and falling off phenomenon, and it has the function of fireproofing; bonding plaster is a kind of new type of building light-board bonding agent, which is made of gypsum as the base material and added with a variety of additives, and it is suitable for the bonding of all kinds of inorganic building wall materials, with the characteristics of non-toxic, tasteless, fast coagulation and fast bonding. It is suitable for bonding between various types of inorganic building wall materials, with non-toxic, odorless, fast, fast solidification, firm bonding and other characteristics, and is a supporting material for the construction of building boards and blocks; gypsum caulk is a gap filler between gypsum boards as well as a repair filler for the walls and cracks.

These gypsum products have a series of different functions, in addition to gypsum and related fillers play a role, the key issue is the addition of cellulose ether additives play a leading role. Since gypsum is divided into anhydrous gypsum and semi-anhydrous gypsum, different gypsum has different effects on the performance of the product, so thickening, water retention and retardation of the gypsum building materials determines the quality of the gypsum building materials. The common problem of these materials is the hollowing and cracking, the initial strength can not be reached, to solve this problem, is to choose the type of cellulose and retarder composite utilization of the problem, in this regard, the general choice of methyl or hydroxypropylmethyl 30,000 - 60,000cps, the amount of addition of 1.5% - 2%. Between, cellulose from which the focus is water retention retarder lubrication. However, in this rely on cellulose ether as a retarder is not reached, must also add citric acid retarder mixed use will not affect the initial strength.

Water retention rate generally refers to the situation where there is no external water absorption, the amount of natural water loss, if the wall is dry, the base surface water absorption and natural evaporation of water loss of the material too quickly, the same will occur hollow drums, cracking phenomenon. This method of use for dry powder mixed use, if the preparation of solution can refer to the preparation of solution.

(4) Thermal insulation mortar

Thermal insulation mortar is a new type of interior wall insulation material, it is a wall material synthesized by thermal insulation materials, mortar and binder. Cellulose in this material, focusing on bonding, increase the role of strength. Generally choose methyl cellulose high viscosity (10000cps or so), the dosage is generally between 2‰-3‰, the use of dry powder mixing method.