Putty powder is mainly composed of film-forming substances (bonding materials), fillers, water-retaining agents, thickeners, defoamers, etc. Common organic chemical raw materials in putty powder mainly include: cellulose, pregelatinized starch, starch ether, polyvinyl alcohol, dispersible latex powder, etc. The performance and use of various chemical raw materials are analyzed one by one below.
1: Definition and difference of fiber, cellulose and cellulose ether
Fiber (US: Fiber; English: Fiber) refers to a substance composed of continuous or discontinuous filaments. Such as plant fiber, animal hair, silk fiber, synthetic fiber, etc.
Cellulose is a macromolecular polysaccharide composed of glucose and is the main structural component of plant cell walls. At room temperature, cellulose is neither soluble in water nor in common organic solvents. The cellulose content of cotton is close to 100%, making it the purest natural source of cellulose. In general wood, cellulose accounts for 40-50%, and there are 10-30% hemicellulose and 20-30% lignin. The difference between cellulose (right) and starch (left):
Generally speaking, both starch and cellulose are macromolecular polysaccharides, and the molecular formula can be expressed as (C6H10O5)n. The molecular weight of cellulose is larger than that of starch, and cellulose can be decomposed to produce starch. Cellulose is D-glucose and β-1,4 glycoside Macromolecular polysaccharides composed of bonds, while starch is formed by α-1,4 glycosidic bonds. Cellulose is generally not branched, but starch is branched by 1,6 glycosidic bonds. Cellulose is poorly soluble in water, while starch is soluble in hot water. Cellulose is insensitive to amylase and does not turn blue when exposed to iodine.
The English name of cellulose ether is cellulose ether, which is a polymer compound with ether structure made of cellulose. It is the product of the chemical reaction of cellulose (plant) with etherification agent. According to the chemical structure classification of the substituent after etherification, it can be divided into anionic, cationic and nonionic ethers. Depending on the etherification agent used, there are methyl cellulose, hydroxyethyl methyl cellulose, carboxymethyl cellulose, ethyl cellulose, benzyl cellulose, hydroxyethyl cellulose, hydroxypropyl methyl cellulose cellulose, cyanoethyl cellulose, benzyl cyanoethyl cellulose, carboxymethyl hydroxyethyl cellulose and phenyl cellulose, etc. In the construction industry, cellulose ether is also called cellulose, which is an irregular name, and it is called cellulose (or ether) correctly. Thickening mechanism of cellulose ether thickener Cellulose ether thickener is a non-ionic thickener, which thickens mainly by hydration and entanglement between molecules. The polymer chain of cellulose ether is easy to form hydrogen bond with water in water, and the hydrogen bond makes it have high hydration and inter-molecular entanglement.
When the cellulose ether thickener is added to the latex paint, it absorbs a large amount of water, causing its own volume to expand greatly, reducing the free space for pigments, fillers and latex particles; at the same time, the cellulose ether molecular chains are intertwined to form a three-dimensional network structure, and the color Fillers and latex particles are enclosed in the middle of the mesh and cannot flow freely. Under these two effects, the viscosity of the system is improved! Achieved the thickening effect we needed!
Common cellulose (ether): Generally speaking, cellulose in the market refers to hydroxypropyl, hydroxyethyl is mainly used for paint, latex paint, and hydroxypropyl methylcellulose is used for mortar, putty and other products. Carboxymethyl cellulose is used for ordinary putty powder for interior walls. Carboxymethyl cellulose, also known as sodium carboxymethyl cellulose, referred to as (CMC): Carboxymethyl cellulose (CMC) is a non-toxic, odorless white flocculent powder with stable performance and is easily soluble in water. Alkaline or alkaline transparent viscous liquid, soluble in other water-soluble glues and resins, insoluble in organic solvents such as ethanol. CMC can be used as binder, thickener, suspending agent, emulsifier, dispersant, stabilizer, sizing agent, etc. Carboxymethyl cellulose (CMC) is the product with the largest output, the widest range of uses, and the most convenient use among cellulose ethers, commonly known as “industrial monosodium glutamate”. Carboxymethyl cellulose has the functions of binding, thickening, strengthening, emulsifying, water retention and suspension. 1. Application of sodium carboxymethyl cellulose in the food industry: sodium carboxymethyl cellulose is not only a good emulsification stabilizer and thickener in food applications, but also has excellent freezing and melting stability, and can improve The flavor of the product prolongs the storage time. 2. The use of sodium carboxymethyl cellulose in the pharmaceutical industry: it can be used as an emulsion stabilizer for injections, a binder and a film-forming agent for tablets in the pharmaceutical industry. 3. CMC can be used as an anti-settling agent, emulsifier, dispersant, leveling agent, and adhesive for coatings. It can make the solid content of the coating evenly distributed in the solvent, so that the coating does not delaminate for a long time. It is also widely used in in paint. 4. Sodium carboxymethyl cellulose can be used as flocculant, chelating agent, emulsifier, thickener, water retaining agent, sizing agent, film-forming material, etc. It is also widely used in electronics, pesticides, leather, plastics, printing, ceramics, Daily-use chemical industry and other fields, and because of its excellent performance and wide range of uses, it is constantly developing new application fields, and the market prospect is extremely broad. Application examples: exterior wall putty powder formula interior wall putty powder formula 1 Shuangfei powder: 600-650kg 1 Shuangfei powder: 1000kg 2 White cement: 400-350kg 2 Pregelatinized starch: 5-6kg 3 Pregelatinized starch: 5 -6kg 3 CMC: 10-15kg or HPMC2.5-3kg4 CMC: 10-15kg or HPMC2.5-3kg Putty powder added carboxymethyl cellulose CMC, pregelatinized starch performance: ① Has a good fast Thickening ability; bonding performance, and certain water retention; ② Improve the anti-sliding ability (sagging) of the material, improve the operating performance of the material, and make the operation smoother; prolong the opening time of the material. ③ After drying, the surface is smooth, does not fall off powder, has good film-forming properties and no scratches. ④ More importantly, the dosage is small, and a very low dosage can achieve a high effect; at the same time, the production cost is reduced by about 10-20%. In the construction industry, CMC is used in the production of concrete preforms, which can reduce water loss and act as a retarder. Even for large-scale construction, it can also improve the strength of concrete and facilitate the preforms to fall off from the membrane. Another main purpose is to scrape the wall white and putty powder, putty paste, which can save a lot of building materials and enhance the protective layer and brightness of the wall. Hydroxyethyl methylcellulose, referred to as (HEC): chemical formula:
1. Introduction to hydroxyethyl cellulose: Hydroxyethyl cellulose (HEC) is a non-ionic cellulose ether made from natural polymer material cellulose through a series of chemical processes. It is an odorless, tasteless, non-toxic white powder or granule, which can be dissolved in cold water to form a transparent viscous solution, and the dissolution is not affected by the pH value. It has thickening, binding, dispersing, emulsifying, film-forming, suspending, adsorbing, surface active, moisture-retaining and salt-resistant properties.
2. Technical indicators Project standard Appearance White or yellowish powder Molar substitution (MS) 1.8-2.8 Water insoluble matter (%) ≤ 0.5 Loss on drying (WT%) ≤ 5.0 Residue on ignition (WT%) ≤ 5.0 PH value 6.0- 8.5 Viscosity (mPa.s) 2%, 30000, 60000, 100000 aqueous solution at 20°C Three, the advantages of hydroxyethyl cellulose High thickening effect
● Hydroxyethyl cellulose provides excellent coating properties for latex coatings, especially high PVA coatings. No flocculation occurs when the paint is a thick build.
● Hydroxyethyl cellulose has higher thickening effect. It can reduce the dosage, improve the economy of the formula, and improve the scrub resistance of the coating.
Excellent rheological properties
● The aqueous solution of hydroxyethyl cellulose is a non-Newtonian system, and the property of its solution is called thixotropy.
● In the static state, after the product is completely dissolved, the coating system maintains the best thickening and opening state.
● In the state of pouring, the system maintains a moderate viscosity, so that the product has excellent fluidity and will not splash.
● When applied by brush and roller, the product spreads easily on the substrate. It is convenient for construction. At the same time, it has good splash resistance.
● Finally, after the coating is finished, the viscosity of the system recovers immediately, and the coating immediately sags.
Dispersibility and Solubility
● Hydroxyethyl cellulose is treated with delayed dissolution, which can effectively prevent agglomeration when dry powder is added. After ensuring that the HEC powder is well dispersed, start hydration.
● Hydroxyethyl cellulose with proper surface treatment can well adjust the dissolution rate and viscosity increase rate of the product.
storage stability
● Hydroxyethyl cellulose has good anti-mildew properties and provides sufficient paint storage time. Effectively prevents pigments and fillers from settling. 4. How to use: (1) Add directly during production This method is the simplest and takes the shortest time. The steps are as follows: 1. Add pure water into a large bucket equipped with a high shear agitator. 2. Start to stir continuously at low speed and slowly sieve the hydroxyethyl cellulose into the solution evenly. 3. Continue stirring until all particles are soaked. 4. Then add antifungal agent and various additives. Such as pigments, dispersing aids, ammonia water, etc. 5. Stir until all the hydroxyethyl cellulose is completely dissolved (the viscosity of the solution increases significantly) before adding other components in the formula for reaction. (2) Prepare mother liquor for use: This method is to prepare mother liquor with a higher concentration first, and then add it to the product. The advantage of this method is that it has greater flexibility and can be directly added to the finished product, but it must be properly stored. The steps are similar to steps (1–4) in method (1): the difference is that no high-shear agitator is needed, only some agitators with enough power to keep hydroxyethyl cellulose uniformly dispersed in the solution , continue stirring until completely dissolved into a viscous solution. It should be noted that the antifungal agent must be added to the mother liquor as soon as possible. V. Application 1. Used in water-based latex paint: HEC, as a protective colloid, can be used in vinyl acetate emulsion polymerization to improve the stability of the polymerization system in a wide range of pH values. In the manufacture of finished products, additives such as pigments and fillers are used to uniformly disperse, stabilize and provide thickening effects. It can also be used as a dispersant for suspension polymers such as styrene, acrylate, and propylene. Used in latex paint can significantly improve thickening and leveling performance. 2. In terms of oil drilling: HEC is used as a thickener in various muds required for drilling, well fixing, well cementing and fracturing operations, so that the mud can obtain good fluidity and stability. Improve the mud carrying capacity during drilling, and prevent a large amount of water from entering the oil layer from the mud, stabilizing the production capacity of the oil layer. 3. Used in building construction and building materials: Due to its strong water retention capacity, HEC is an effective thickener and binder for cement slurry and mortar. It can be mixed into mortar to improve fluidity and construction performance, and to prolong the water evaporation time , Improve the initial strength of concrete and avoid cracks. It can significantly improve its water retention and bonding strength when used for plastering plaster, bonding plaster, and plaster putty. 4. Used in toothpaste: due to its strong resistance to salt and acid, HEC can ensure the stability of toothpaste. In addition, toothpaste is not easy to dry due to its strong water retention and emulsifying ability. 5. When used in water-based ink, HEC can make the ink dry quickly and impermeable. In addition, HEC is also widely used in textile printing and dyeing, papermaking, daily chemicals and so on. 6. Precautions for using HEC: a. Hygroscopicity: All types of hydroxyethyl cellulose HEC are hygroscopic. The water content is generally below 5% when leaving the factory, but due to different transportation and storage environments, the water content will be higher than when leaving the factory. When using it, just measure the water content and deduct the weight of the water when calculating. Do not Expose it to the atmosphere. b. Dust powder is explosive: if all organic powders and hydroxyethyl cellulose dust powder are in the air at a certain proportion, they will also explode when they encounter a fire point. Proper operation should be done to avoid dust powder in the atmosphere as much as possible. 7. Packaging specifications: The product is made of paper-plastic composite bag lined with polyethylene inner bag, with a net weight of 25 kg. Store in a ventilated and dry place indoors when storing, and pay attention to moisture. Pay attention to rain and sun protection during transportation. Hydroxypropyl methyl cellulose, referred to as (HPMC): hydroxypropyl methyl cellulose (HPMC) is an odorless, tasteless, non-toxic white powder, there are two types of instant and non-instant, instant, When met with cold water, it quickly disperses and disappears into the water. At this time, the liquid has no viscosity. After about 2 minutes, the viscosity of the liquid increases, forming a transparent viscous colloid. Non-instant type: It can only be used in dry powder products such as putty powder and cement mortar. It cannot be used in liquid glue and paint, and there will be clumping.
Post time: Dec-26-2022