Views: 12 Author: Site Editor Publish Time: 2022-01-20 Origin: Site
Cellulose Ether is cellulose derivatives made from Cellulose by etherification reaction of one or more etherifying agents and grinding of dry powder. According to the different chemical structure of ether substituent, cellulose ether can be divided into anionic, cationic and non-ionic ether.
Cellulose ether mainly include:
Hydroxypropyl methyl cellulose (HPMC)
Methyl Hydroxyethyl cellulose (MHEC)
Hydroxyethyl cellulose (HEC)
Hydroxyethyl methyl cellulose (HEMC)
Sodium Carboxymethyl cellulose (CMC)
Non-ionic ether is divided into water-soluble ether and oil-soluble ether, non-ionic water-soluble ether is mainly used in mortar products. In the presence of calcium ions, ionic cellulose ether is unstable, so it is rarely used in dry mixed mortar products with cement, hydrated lime and other cementing materials. Non-ionic water-soluble cellulose ether is widely used in the building materials industry because of its suspension stability and water retention.
1. Chemical properties of cellulose ether
Each cellulose ether has the basic structure of cellulose - the dehydrated glucose structure. In the process of producing cellulose ether, the cellulose fiber is heated in alkaline solution first, and then treated with etherifying agent. The fibrous reaction product is purified and ground to form a uniform powder with a certain fineness.
In the production process of MC, only methane chloride is used as etherifying agent. HPMC production in addition to the use of methane chloride, but also use propylene oxide to obtain hydroxypropyl substituent group. Various cellulose ethers have different methyl and hydroxypropyl substitution rates, which affect the solubility of cellulose ethers and the properties of hot gel temperature.
2. Application scenarios of cellulose ether
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 industry, it is a kind of binder and slow release skeleton material, because cellulose has a variety of composite effects, so it is the most widely used field. The following focuses on the use of cellulose ether in a variety of building materials and the role.
(1) In latex paint:
In the latex paint line, to choose hydroxyethyl cellulose, the general specification of viscosity is RT3000-50000cps, it corresponds to HBR250 specifications, the reference dosage is generally 1.5‰-2‰. The main role of hydroxyethyl 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 following three methods are used: 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. ⅱ, with mother liquor hou use: this method can choose the instant type, and has the effect of mildew proof cellulose. 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. ⅲ, with porridge for use: because organic solvents are bad solvents for hydroxyethyl (insoluble) so you can use these solvents 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.
(2) 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 resistant putty is divided into dry powder putty and putty paste two kinds, the two kinds of putty generally choose modified methyl cellulose and hydroxypropyl methyl two kinds, viscosity specification is generally in 3000-60000cps 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. 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 filling material, especially the quality of gray calcium is also extremely important. Because of the high viscosity of cellulose, it also enhances the buoyancy of putty, and avoids the phenomenon of flow hanging in construction, and it is more comfortable and labor-saving after scraping. In powder putty, cellulose ether should be appropriately added to the factory point, its production, use is more convenient, filling material and auxiliary dry powder can be evenly mixed, construction is more convenient, the site water distribution, how much with how much.
(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, Add eight water-retaining agent cellulose in mortar concrete to choose hydroxypropyl methyl or methyl cellulose, viscosity specifications in 20000--60000cps between, add 2%--3%. About, the water retention rate can be increased to more than 85%, in mortar concrete use method for dry powder evenly mixed after the mouth into the water can be.
(4) Gypsum plaster, bonding plaster, caulking plaster:
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 material gypsum products have been rapid development. At present the commonnest gesso goods has stucco gesso, caking gesso, set gesso, tile caking agent to wait. Plastering plaster is a kind of good quality interior wall and roof plastering material, with it wipe the wall is delicate and smooth, do not drop powder and base bond firmly, no cracking off phenomenon, and has fire prevention function; Adhesive gypsum is a new type of building light board adhesive, gypsum as the base material, plus a variety of adding force mouth agent 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 is a building board, block construction supporting materials; Gypsum seam filling agent is gypsum plate between the gap filling material and wall, crack repair filling. These gypsum products have a range of different functions, in addition to gypsum and related fillers to play a role, the key issue is the added cellulose ether additives play a leading role. Because gesso is divided have without water gesso and the cent of half water gesso, different gesso is different to the performance effect of the product, increase so thick, protect water, slow coagulate the quality that decides gesso building materials. The common problem of these materials is hollow drum cracking, the initial strength is not up to, 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 30000--60000cps, adding amount is 1.5%-- 2%. Between, the focus of cellulose is water retention and slow condensation lubrication. However, in this to rely on cellulose ether as retarder is not up to, must also add citric acid retarder after mixed use will not affect the initial strength. Water retention rate generally refers to the amount of natural water loss in the absence of external water absorption. If the wall is dry, the base surface absorbs water and natural evaporation makes the material lose water too fast, and there will also be empty drum and cracking phenomenon. This method of use is to mix dry powder, if the preparation of solution can refer to the preparation method of solution.
(5) Insulation mortar
Thermal insulation mortar is a new type of interior wall thermal insulation material in north China. It is a wall material synthesized by thermal insulation material, mortar and binder. In this material, cellulose plays a key role in bonding and increasing strength. Generally, methyl cellulose with high viscosity (about 10000eps) is selected, and the dosage is generally between 2‰ and 3‰. The method of use is dry powder mixing.
(6) interface agent
The interface agent is HPMC20000cps, the tile binder is 60000cps or more, and the interface agent is mainly used as thickener, which can improve the tensile strength and arrow strength. In the tile bonding water retention agent to prevent the tile from losing water too fast falling off.
3. Industrial chain
(1) Upstream industry
The main raw materials for the production of cellulose ether include refined cotton (or wood pulp) and some common chemical solvents, such as propylene oxide, chloromethane, liquid alkali, tablet alkali, ethylene oxide, toluene and other auxiliary materials. The upstream enterprises of this industry include refined cotton, wood pulp production enterprises and some chemical enterprises. The fluctuation of the price of the main raw materials mentioned above will have different effects on the production cost and selling price of cellulose ether.
Refined cotton cost is relatively high. Taking building materials grade cellulose ether as an example, during the reporting period, the proportion of refined cotton cost in building materials grade cellulose ether sales cost was 31.74%, 28.50%, 26.59% and 26.90%, respectively. The price fluctuation of refined cotton will affect the production cost of cellulose ether. The main raw material of producing refined cotton is cotton staple. Cotton staple is one of the by-products in cotton production, mainly used to produce cotton pulp, refined cotton, nitrocellulost and other products. The utilization value and use of cotton staple is different from that of cotton, and its price is obviously lower than that of cotton, but it has a certain correlation with the fluctuation of cotton price. The price fluctuation of cotton staple will affect the price of refined cotton.
The violent fluctuation of refined cotton price will affect the production cost, product pricing and profitability of enterprises in this industry to varying degrees. In the case of high refined cotton price and wood pulp price is relatively cheap, in order to reduce costs, wood pulp can be used as a refined cotton substitute and supplement, mainly used for the production of medical food grade cellulose ether and other low viscosity cellulose ether. In 2013, China planted 4.35 million hectares of cotton and produced 6.31 million tons of cotton, according to the website of the National Bureau of Statistics. According to the statistics of China Cellulose Industry Association, in 2014, the total output of refined cotton of major domestic refined cotton production enterprises was 332,000 tons, with abundant supply of raw materials.
The main raw materials for the production of graphite chemical equipment are steel and graphite carbon. The price of steel and graphite carbon accounts for a higher proportion of the production cost of graphite chemical equipment. The price fluctuation of these raw materials will have a certain impact on the production cost and selling price of graphite chemical equipment.
(2) cellulose ether downstream industry situation
Cellulose ether as "industrial sodium glutamate", cellulose ether adding proportion is low, a wide range of applications, downstream industries scattered in all walks of life in the national economy.
Under normal circumstances, the downstream construction industry and real estate industry will have a certain impact on the demand growth of building materials grade cellulose ether. When the domestic construction industry and real estate industry growth rate is faster, the domestic market for building materials grade cellulose ether demand growth rate is faster. When the growth rate of the domestic construction industry and real estate industry slows down, the growth rate of the demand for building materials grade cellulose ether in the domestic market will slow down, making the competition in the industry more intense, and speeding up the survival of the fittest process of enterprises in the industry.
Since 2012, under the environment of slowing growth of the domestic construction industry and real estate industry, the demand for building materials grade cellulose ether in the domestic market has not fluctuated significantly. The main reasons are as follows: 1. The overall scale of the domestic construction industry and real estate industry is large, and the total market demand is large; The main consumer market of building materials grade cellulose ether from the economically developed areas and the first and second tier cities, gradually expand to the Midwest and the third tier cities, domestic demand growth potential and space expansion; Two, the amount of cellulose ether added to the cost of building materials is low proportion, the amount of a single customer is small, customers scattered, easy to produce rigid demand, the total demand of the downstream market is relatively stable; Three, building materials market price change is affecting cellulose ether demand structure change, the important factors that cellulose ether level since 2012, building materials price decline is larger, the high-end products in the price drop is larger, attract more customers purchasing selection, increased the demand for high-end products in the, and squeezing the ordinary type products market demand and price space.
The development of pharmaceutical industry and the growth rate of pharmaceutical industry will affect the demand change of pharmaceutical grade cellulose ether. The improvement of people's living standard and the developed food industry are conducive to driving the market demand for food-grade cellulose ether.
6. Development trend of cellulose ether
Due to the existence of cellulose ether market demand for structural differences, the formation of the strength of different enterprises to coexist. In view of the obvious structural differentiation characteristics of market demand, domestic cellulose ether manufacturers combined with their own strength to take a different competition strategy, and also a good grasp of the development trend and direction of the market.
(1) to ensure the stability of product quality, will still be the core competition points of cellulose ether enterprises
Cellulose ether in the industry most of the downstream enterprises in the production cost is relatively small, but the product quality is greater. Middle and high-end customer groups in the use of a brand of cellulose ether model before, to go through the formula experiment. After forming a stable formula, it is usually not easy to replace other brands of products, but also put forward higher requirements for the quality stability of cellulose ether. This phenomenon is more prominent in domestic and foreign large building materials manufacturing enterprises, pharmaceutical accessories, food additives, PVC and other high-end fields. In order to improve the competitiveness of products, manufacturers must ensure that the supply of different batches of cellulose ether can maintain quality stability, in order to form a better market reputation.
(2) To improve the technical level of product application is the development direction of domestic cellulose ether enterprises
In the case of cellulose ether production technology increasingly mature, a higher level of application technology is conducive to enterprises to enhance comprehensive competitiveness, the formation of stable customer relations. The well-known cellulose ether enterprises in developed countries mainly adopt the competitive strategy of "facing large high-end customers + development of downstream use and usage", develop cellulose ether use and use formula, and configure a series of products according to different subdivision application fields to facilitate the use of customers, and to cultivate the downstream market demand. The competition of cellulose ether enterprises in developed countries has entered the field of application technology from the product.
Cellulose ether, known as "industrial sodium glutamate", has the advantages of wide use, small unit dosage, good modification effect, friendly to the environment, etc., is widely used in building materials, medicine, food, textile, daily chemical, petroleum exploitation, mining, paper making, polymerization reaction and aerospace and many other fields.