Cellulose ether is a kind of non-ionic semi-synthetic polymer, with water solubility and solvability of two kinds, in different industries caused by the role is different, such as in chemical building materials, it has the following composite effect: ① water retaining agent ② thickening agent ③ leveling ④ film formation ⑤ binder; In the polyvinyl chloride industry, it is an emulsifier, dispersant; In the pharmaceutical industry, it is a kind of binder and slow and controlled release skeleton material, because cellulose has a variety of composite effects, so it is the most widely used field. Here I focus on the use of cellulose ether in environmental protection building materials and the role.
1, latex paint
In LATEX paint line, want to CHOOSE hydroxyethyl cellulose, the general specification of viscosity is RT30000- 50000CPS, the reference amount is generally 1.5‰-2‰ left and right sides. The main role of hydroxyethyl in latex paint is to thicken, prevent pigment gelation, contribute to pigment dispersion, latex, stability, and can improve the viscosity of components, contribute to the leveling performance of construction: Hydroxyethyl cellulose is more convenient to use, cold and hot water can be dissolved, and is not affected by PH value, between PH 2 and 12 can be used, the use of the following three methods:
I. Directly add:
This method should choose hydroxyethyl cellulose delayed type — dissolved time of more than 30 minutes of hydroxyethyl cellulose, its use steps are as follows: (1) to have high should cut blender container and quantitative pure water (2) people began to slow stirring continuously, at the same time slowly add hydroxyethyl evenly to 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.
ⅱ, equipped with mother liquor waiting:
This method can choose instant type, and has mildew – proof effect of cellulose. This method has the advantage of greater flexibility, can be directly added to latex paint, preparation method is the same as ①- ④ steps.
ⅲ. Serve with porridge:
Because organic solvents are undesirable (insoluble) to hydroxyethyl, they can be used to make porridge. The MOST COMMONLY USED ORGANIC SOLVENT IS THE ORGANIC LIQUID IN LATEX PAINT FORMULA, BE LIKE GLYCOL, PROPYLENE GLYCOL AND FILM-forming AGENT (LIKE DIETHYLENE glycol butyl acetic acid GREASE), CELLULOSE OF HYDROXYETHYL OF CONGER MATERIAL CAN JOIN PAINT DIRECTLY IN, AFTER JOINING STILL CONTINUE STIRRING TO DISSOLVE COMPLETELY SO FAR.
2, scraping the wall putty
At present, the environmental protection type putty, which is water-resistant and scrubbing resistant in most cities, has been paid attention to by people basically. In the past few years, because the putty made of building glue radiates formaldehyde gas to damage people’s health, the building glue is made of polyvinyl alcohol and formaldehyde for acetal reaction. Therefore, this material is gradually eliminated by people, and the replacement of this material is cellulose ether series products, that is to say, the development of environmental protection building materials, cellulose is the only one kind of material.
In the water resistant putty is divided into two kinds of dry powder putty and putty paste, these two kinds of putty generally want to choose modified methyl cellulose and hydroxypropyl methyl two kinds, viscosity specifications are generally between 3000-60000CPS the most appropriate, the main role of cellulose in the putty is water retention, bonding, lubrication, etc.
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, so the specification viscosity and infiltration of cellulose of the two formulas are not the same, the general amount of adding is about 2‰-3‰.
In blow wall be bored with child construction, the wall base has certain absorbent (brick wall of the bibulous rate was 13%, the concrete is 3-5%), coupled with the evaporation of the outside world, so if be bored with child water loss too fast, would lead to crack or the phenomenon such as pollen, so that the strength of the putty weakened, therefore, after joining cellulose ether will solve this problem. But the quality of the filler, especially the calcium ash, is also extremely important. Because of the high viscosity of cellulose, it also enhances the floating force of putty, and avoids the phenomenon of flow hanging in construction, and it is more comfortable and labor-saving after scraping.
3, concrete mortar
In concrete mortar, really achieve ultimate strength, must make the cement hydration reaction completely, especially in the summer, in the construction of the concrete mortar water loss too fast, completely hydrated measures on curing water, this method is a waste of water resource and inconvenient operation, the key is just on the surface, water and hydration is still not completely, so the ways to solve this problem, In the mortar concrete generally choose to add hydroxypropyl methyl cellulose or methyl cellulose, viscosity specifications between 20000– 60000CPS, add about 2‰–3‰, water retention rate can be increased to more than 85%, the use of mortar concrete for dry powder evenly mixed after adding water can be.
4, paint gypsum, adhesive gypsum, caulking gypsum
With the rapid development of the construction industry, people’s demand for new building materials is also increasing day by day, because of the increase of people’s awareness of environmental protection and the continuous improvement of construction efficiency, cementitious materials gypsum products have been rapidly developed. At present the most common gypsum products have stucco gypsum, bonded gypsum, embedded gypsum, tile binder.
Stucco plaster is a kind of good quality interior wall and roof plastering material, with it to wipe the wall is delicate and smooth, not powder, solid bond with the base, no cracking off phenomenon, and has fire protection function; Adhesive gypsum is a new type of building light plate binder, is gypsum as the base material, adding a variety of additives and made of adhesive material, it is suitable for all kinds of inorganic building wall materials between the bond, with non-toxic, tasteless, early strength fast setting, bonding and other characteristics, is the building board, block construction supporting materials; Gypsum sealant is the filler for the gap between gypsum plates and the repair of the wall and cracks.
These gypsum products have a range of different functions, in addition to gypsum and related fillers play a role, the key issue is that the added cellulose ether additives play a leading role. Because GESSO IS DIVIDED INTO THE CENT OF ANHYDROUS GESSO AND HEMIHYDRATE GESSO, DIFFERENT GESSO EFFECT IS DIFFERENT TO THE PERFORMANCE OF THE PRODUCT, SO THICKENING, WATER RETENTION, SLOW SETTING IS DECIDING THE QUALITY OF GESSO BUILDING MATERIALS. The common problem of these materials is empty drum cracking, the initial strength is not up to this problem, to solve this problem, is to choose the type of cellulose and retarder compound use method problem, in this respect, the general choice of methyl or hydroxypropyl methyl cellulose HPMC 30000– 60000CPS, add between 1.5‰–2‰, cellulose from the focus is water retention retarding lubrication.
However, in this process, it is not possible to rely on cellulose ether as retarder, and citric acid retarder must be added to the mixture so that the initial strength will not be affected.
Water retention rate generally refers to the amount of natural water loss without external water absorption. If the wall is dry, the base surface water absorption and natural evaporation make the material lose water too fast, and there will also be empty drum and cracking phenomenon.
This use method for dry powder mixed use, if the solution can refer to the solution preparation method.
5. Thermal insulation mortar
Thermal insulation mortar is a new wall insulation material in northern China. It is a wall material synthesized by thermal insulation material, mortar and binder. In this material, cellulose plays an important role in bonding and increasing strength. Generally, methyl cellulose with high viscosity (about 10000cps) is selected, and the dosage is generally between 2‰ and 3‰. The method is dry powder mixing method.
6, interface agent
Interface agent selection HPMC20000cps, tile binder selection of more than 60000CPS, in the interface agent focus on thickening agent, can improve the tensile strength and arrow strength and other effects.