Anhui hydroxypropyl methyl ether manufacturer. [Jilong building materials] the method of filter paper is to evaluate the water retention of HPMC through the water absorption of filter paper. It consists of a certain height of metal ring-shaped test mold, filter paper and glass supporting plate. Under the test mold, there are 6 layers of filter paper, including fast filter paper and slow filter paper. First weigh the pallet and 5 layers of slow filtering filter paper with a precision balance. After mixing, pour the mortar into the test mold and scrape it flat. After 15min, weigh the pallet and 5 layers of slow filtering filter paper. Calculate according to the following formula: M = (m1-m2) / SM - water loss, g / mm2m1 - weight of pallet + 5 layers of slow filtering paper; GM2 - weight of pallet + 5 layers of slow filtering paper after 15min; GS - area of the test mold mm2 can also directly observe the water absorption degree of the filter paper. The lower the water absorption of the filter paper, the better the water retention. This test method is easy to operate, and general enterprises can meet the test conditions. Three surface drying time test method: this method can refer to gb1728 "paint film, putty film drying time test method", scrape and apply the mixed mortar on the asbestos cement board, with the thickness controlled at 3mm. Method 1. The cotton ball method is used to lightly prevent a degreasing cotton ball on the mortar surface. The distance between the nozzle and the cotton ball is 10-15cm every certain time, and the cotton ball is blown gently along the horizontal direction. If the cotton ball can be blown away and there is no cotton thread on the mortar surface, the surface is considered dry. The longer the time interval, the better the water retention. Method 1. Touch the mortar surface gently with clean fingers at regular intervals. If you feel some sticky but no mortar on your fingers, the surface can be considered dry. The longer the time interval, the better the water retention. Among the above methods, filter paper method and finger touch method are commonly used and simple. Through the above methods, users can preliminarily evaluate the water retention of cellulose ether from different manufacturers.
The addition of HPMC is affected by air temperature, air temperature and wind pressure speed, which will affect the evaporation rate of water in cement mortar and gypsum based products. Therefore, in different seasons, the same amount of hydroxypropylmethylcellulose products have some differences in water retention effect. In the concrete construction, the water retention effect of the slurry can be adjusted by increasing or decreasing the amount of HPMC. The water retention of hydroxypropyl methylcellulose ether at high temperature is an important index to distinguish the quality of hydroxypropyl methylcellulose ether. The excellent hydroxypropylmethylcellulose series products can effectively solve the problem of water conservation under high temperature. In high temperature seasons, especially in hot and dry areas and sunny areas, high quality hydroxypropylmethylcellulose is needed to improve the water retention of slurry. The high-quality hydroxypropyl methylcellulose has very good uniformity. Its methoxy and hydroxypropyl groups are evenly distributed along the cellulose molecular chain, which can improve the ability of the oxygen atoms on the hydroxyl and ether bonds to associate with water to form hydrogen bonds, so that the free water can become the combined water, thus effectively controlling the water evaporation caused by high temperature weather, and achieving high water retention. High quality cellulose HPMC can disperse uniformly and effectively in cement mortar and gypsum based products, and wrap all solid particles, and form a layer of wetting film. The water in the base is released gradually in a long time, and hydration reaction occurs with inorganic cementitious materials, so as to ensure the bonding strength and compressive strength of materials.
The differences between the cold water and hot water soluble properties of HPMC: ① the cold water soluble type of HPMC is treated by glyoxal surface, which is rapidly dispersed in cold water, but not really dissolved. Only when the viscosity is up can it be dissolved. ② Hydroxypropylmethylcellulose was not treated by glyoxal. Glyoxal is dispersed quickly if it has a large amount of glyoxal, but the viscosity of glyoxal is slow if it has a small amount of glyoxal, on the contrary. The main raw materials for the production of HPMC are refined cotton, sodium hydroxide, methyl chloride, propylene oxide, etc.
The content of methoxy is directly related to the etherification degree of cellulose ether. The content of methoxy can be adjusted by controlling the formula, reaction temperature and reaction time. At the same time, the degree of etherification affects the degree of substitution of hydroxyethyl or hydroxypropyl. Therefore, generally, the high gel temperature of cellulose ether water retention will be a little worse. This production process needs to be explored, so it is not because of the low content of methoxy, the price of cellulose ether will be low, on the contrary, the price will be higher. The gel temperature is determined by methoxy, and the water holding capacity is determined by hydroxypropyl. There are only three groups on cellulose that can be replaced. Find the right temperature, the right water retention, and then determine the type of cellulose. Gel temperature is a critical point in the application of cellulose ether. When the ambient temperature exceeds the gel temperature, the cellulose ether will precipitate from water and lose its water retention. The cellulose ether gel temperature in the market can basically meet the needs of mortar environment (except for special environment). Personally, it is not necessary to pay special attention to the performance index of gel temperature when mortar is applied. Of course, manufacturers of cellulose ether must consider it.
Thermal insulation mortar powder is a kind of chemical powder used in many industries, such as construction, decoration, petroleum, mining, etc. because of its wide application range, the demand is large, so the manufacturer naturally produces a large number of mortar powder, and now in winter, the storage of rubber powder should pay attention to moisture-proof measures. The first requirement of the warehouse for storing mortar special rubber powder is drying. The rubber powder needs to be mixed with water in use, but the moisture-proof should be paid attention to in daily storage. Therefore, the requirement for mortar powder manufacturers to select the warehouse is dry and sunny, and there should be no water in the warehouse. Sunny can ensure the temperature in the warehouse is appropriate, and the rubber powder will not freeze at low temperature. The warehouse for storing thermal insulation mortar rubber powder shall also be well ventilated, and the air shall be humid after snowing in winter. Even if the warehouse is sunny, it is easy to accumulate humid air. Select a well ventilated warehouse to store mortar powder, which can open the doors and windows in time to disperse the moisture in the warehouse and ensure the powder is dry. In addition, the ground in the warehouse shall be lime ground or paved with boards as much as possible, so as to prevent the moist air from the ground from entering into the rubber powder bag, which will cause the rubber powder to be damp and caked. Mortar powder can be used after mixing with cold water, but before unsealing or selling, the manufacturer shall ensure the drying of the powder. Therefore, one way for manufacturers to store mortar powder in winter is to choose a dry and ventilated warehouse. The drying requirements are not wet, and the air temperature and humidity are appropriate. Ventilation can timely disperse the humid air in the warehouse and effectively prevent the rubber powder from getting wet. It is an important method to prevent moisture in winter.