-
What is the shelf life of tile adhesive?
What is the shelf life of tile adhesive?
In a cool and dry environment, the shelf life of unopened tile adhesive is 1 year. Tiles are agglomerated, indicating that their active ingredients have begun to react and should be discarded.
Mixing time of tile adhesive
The tile adhesive should be stirred with a low-speed mixer (500r/min). The powder is added to the water and stirred for 3-5 minutes to form a uniform paste-free glue.
-
The relationships of Wall Putty and HPMC
Question: Is there any relationship between the putty powder on the wall and HPMC?
Answer: In the putty powder, HPMC plays three roles of thickening, water retention and construction. Does not participate in any chemical reactions. Reasons for bubbles:
1. Too much water.
2. If the bottom layer is not dry, just scrape another layer on it, and it is easy to foam.
3. The reason for the wall surface, the uneven cement wall, is the easiest to foam.
-
How many types of construction grade cellulose ethers?
Four type of important construction grade cellulose ethers
1. Methyl cellulose (MC)
After the refined cotton is treated with alkali, methane chloride is used as the etherifying agent, and a series of reactions are made into fiber cellulose ether. The general degree of substitution is 1.6-2.0, and the solubility is also different according to the degree of substitution. Belongs to non-ionic cellulose ether.
2. Hydroxyethyl cellulose (HEC)
It is made from refined cotton after alkali treatment, in the presence of acetone, using ethylene oxide as an etherifying agent for reaction. The degree of substitution is generally 1.5-2.0. It has a strong new water and is easy to absorb moisture.
3. Hydroxypropyl methyl cellulose (HPMC)
Hydroxypropyl methyl cellulose is a cellulose variety whose output and dosage have been increasing rapidly in recent years. It is a non-ionic cellulose mixed ether made from refined cotton after alkali treatment, using propylene oxide and methyl chloride as etherifying agents through a series of reactions. The degree of substitution is generally 1.2-2.0. Its properties are different depending on the ratio of methoxy content and hydroxypropyl content.
4. Carboxymethyl cellulose (CMC)
After being treated with alkali by natural fiber (cotton), etc., sodium chloroacetate is used as an etherifying agent, which is made into ionic cellulose ether through a series of reaction processes. The degree of substitution is generally 0.4-1.4, and its performance and substitution degree have a greater impact.
-
How much hydroxypropyl methylcellulose (HPMC) is added to wall putty powder?
How much hydroxypropyl methylcellulose (HPMC) is added to wall putty powder?
The amount of HPMC used in practical applications varies depending on the climate environment, temperature, local grey calcium quality, formula of putty powder and "quality required by customers".
Dosage: 4-5kg, test before large production.
-
What types of water reducers are commonly used in engineering and what are their characteristics?
What types of water reducers are commonly used in engineering and what are their characteristics?
At present, water reducing agents mainly include lignin series, naphthalene series, resin series, molasses series and polycarboxylic acid, etc. There are also air-entraining agents and non-air-entraining agents. According to its effect on concrete setting and hardening speed, it can be divided into three types: ordinary type, early strength type and retarding type.
(1) lignosulphonate water reducer
The main species is calcium lignin sulfonate, which is a brownish-yellow powder produced by extracting alcohol, waste wood pulp, evaporated, sulfonated, and spray-dried. Liquid agent. The suitable dosage is 0.2% ～ 0.3%, the water reduction rate is about 10%, if the water is not reduced, the slump can be increased by about 10cm, and the 28d strength of concrete can be increased by 10% -20%. If the strength is kept unchanged, it can be saved Cement 10%; but wood calcium has a retarding effect on concrete, generally retarding for 1 to 3 hours, the retarding property is stronger at low temperature, the amount is too much, and the retarding is serious. Moreover, wood calcium is an air-entraining water-reducing agent, which increases the air content of concrete from 2% to 3.6% when not mixed, which has an effect on the strength of concrete, but is beneficial to the frost resistance of concrete.
(2) naphthalene formaldehyde water reducer
Naphthalene-based water reducing agent is naphthalene and naphthalene homologues fractionated from coal tar as raw materials. After sulfonation and condensation. It has a strong dispersion effect on cement, so its effects of water reduction, reinforcement, and durability improvement are all superior to lignin, which is a high-efficiency water-reducing agent. The general water reduction rate is above 15%, the early strength is remarkable, and the concrete is strengthened by more than 20% at 28d. The suitable dosage is about 0.5% to 1.5%, and the PH value is 7 to 9. It is suitable for all concrete projects, and is more suitable for preparing high-strength concrete and fluidized concrete.
(3) Molasses water reducing agent
The molasses water-reducing agent is the waste liquid left by the extraction of sugar in the production process of the sugar factory. It is neutralized with lime to form salt-like substances. It is a tan powdery solid or paste-like liquid. In addition to its function, it also has a significant retarding effect, so it is a retarding type water reducing agent, and the initial setting time and final setting time are generally extended by more than 3h. The suitable dosage is 0.2% ～ 0.3%, the water reduction rate is 6% ～ 10%, the concrete 28d strength is increased by 15% ～ 20%, if the original strength is kept unchanged, the cement can be saved by about 10%.
(4) Polycarboxylic acid water reducing agent
The polycarboxylic acid superplasticizer has a special comb structure, which promotes the dispersion of cement particles through the electrostatic effect and steric hindrance effect, improves the workability of the concrete mixture, can effectively reduce the water consumption, and improve the physical properties of the concrete. Including concrete compressive, tensile, flexural strength and elastic modulus, improve concrete frost resistance and impermeability; can adjust the setting time of concrete, improve the construction performance of concrete; at the same time, it can also reduce water bleeding and improve concrete compaction And other effects to improve the durability of concrete. Its effective admixture is 0.1% to 0.2%, the dispersion of polycarboxylic acid water-reducing agent is strong, the admixture is low, the concrete slump loss is small, the compatibility with different cements is good, it does not cause obvious retardation, micro-citation gas.
-
What is the technical and economic effect of high-performance concrete water reducer?
What is the technical and economic effect of high-performance concrete water reducer?
①When the water consumption is constant, the concrete slump can increase by 10 ～ 20cm;
②Keeping the workability of concrete unchanged, it can reduce water by 10% to 50%, and the concrete strength can be increased by 15% to 20%, especially the early strength increase is more significant;
③ When the concrete strength is kept unchanged, the cement consumption can be saved by 10% to 15%;
④ The rate of heat release of cement hydration slows down, and the peak of heat release is delayed;
⑤ The bleeding and segregation of concrete has been greatly improved;
⑥Concrete water permeability can be reduced by 40% ～ 80%, improving the ability of impermeability, frost resistance, chemical resistance and anti-corrosion;
⑦Special concrete can be formulated, which will be more economical, convenient and flexible than using special cement.
-
What is hydroxyethyl cellulose- HEC?
What is hydroxyethyl cellulose- HEC?
Hydroxyethyl cellulose (HEC), a white or light yellow, odorless, non-toxic fibrous or powdery solid, prepared by etherification of basic cellulose and ethylene oxide (or chloroethanol). Non-ionic soluble cellulose ethers. Because HEC has good characteristics of thickening, suspending, dispersing, emulsifying, bonding, film-forming, protecting moisture and providing protective colloids, it has been widely used in petroleum mining, coatings, construction, pharmaceuticals, food, textiles, paper and polymers Polymerization and other fields.
How is it after hydroxyethyl cellulose - HEC meets water-based coating?
As a nonionic surfactant, hydroxyethyl cellulose has the following properties in addition to thickening, suspending, binding, floating, film-forming, dispersing, retaining water, and providing protective colloids:
HEC is soluble in hot or cold water, and does not precipitate at high temperature or boiling, making it have a wide range of solubility and viscosity characteristics, and non-thermal gelation;
The water retention capacity is twice as high as that of methyl cellulose, and it has better flow regulation;
The dispersing ability of HEC is the worst compared with the recognized methyl cellulose and hydroxypropyl methyl cellulose, but the protective colloid is the strongest.
The non-ionic itself can coexist with other water-soluble polymers, surfactants and salts in a wide range. It is an excellent colloid thickener containing high-concentration electrolyte solution;
How to use hydroxyethyl cellulose -HEC?
Join directly in production-this method is the simplest and takes a short time.
Add purified water to a vat equipped with a high-shear mixer. Start stirring constantly at low speed and slowly sieve the hydroxyethyl cellulose - HEC evenly into the solution. Continue stirring until all particles are wet. Then add preservatives and various additives. Such as pigments, dispersion aids, ammonia, etc. Stir until all hydroxyethyl cellulose - HEC is completely dissolved (the viscosity of the solution increases significantly) before adding the other ingredients in the formula to react.
Equipped with mother liquor
It is prepared with a higher concentration of mother liquor, and then added to the product. The advantage of this method is that it has greater flexibility and can be added directly to the finished product, but it must be properly stored. The steps of this method are similar to most of the steps in method one; the difference is that there is no need for a high-resistance blender, only a stirrer with sufficient power to keep the hydroxyethyl cellulose - HEC uniformly dispersed in the solution can continue Stir until completely dissolved into a viscous solution. However, it must be noted that the mold inhibitor must be added to the mother liquor as soon as possible.
-
HPMC Questions in Applications
HPMC Questions in Applications
Q: What’s applications of HPMC construction grade?
A: Used for tile glue, wall putty/ wall coatings.
Q: What’s dosage of HPMC in adhesive mortar ?
A: 2-3KG/TON in warm place ; 3-4 KG/TON, in cold place.
Q: What’s the viscosity for wall putty/ wall coating ?
A: 100000cps is enough for wall putty/ wall coating.
And also 70000-80000cps is good for wall putty with good water retention.
Q: what’s the functions of HPMC in mortar?
A : HPMC works as water retention, thickener, workability agent in mortar.
Q: what’s the viscosity of hpmc in adhesive mortar?
A: 150000cps of hpmc is better for adhesive mortar.
Q: what’s the viscosity of hpmc in selfleveling mortar?
A: 400 CPS is good for selfleveling mortar.
-
What is hydroxypropyl methylcellulose?
Hydroxypropyl Methylcellulose. Excipient (pharmacologically inactive substance) Hypromellose, also commonly known as hydroxypropyl methycellulose (HPMC) is a thickener,stabilizer, and film-former in the construction industry.
-
What's application of HEMC ?
Used in construction, extrusion and paint as its main applications, hemc showsexcellent thermal stability and good water retention.
