Sponges, a porous material, have good water absorption and can be used to clean items. People commonly use sponges made from wood cellulose fibers or foamed plastic polymers. There are also natural sponges made from sponge animals, and most natural sponges are used for body cleaning or painting. There are also three other types of synthetic sponges made from other materials, namely low-density polyether (non-absorbent sponges), polyvinyl alcohol (highly absorbent material with no visible pores) and polyester.
Polyurethane sponge block foam, sometimes, there will be surface cracking, variable length will appear sometimes in the side sometimes but in the middle, what exactly is the reason? The following summary of a few points for your reference, welcome to smash bricks!
1, increase the amount of tin catalyst at the same time less amine dosage, if all the right amount to exclude is not the problem on the silicone oil.
2, improve the starting foaming area of the drying channel and conveyor belt temperature.
3, check whether the side paper and conveyor belt speed is synchronized, the height of both sides of the tilt board is at the same level; assembly line transmission and side transmission is uniform, synchronized, must pay attention to the speed of foaming and transmission speed in close cooperation.
4、Take the side machine control well, take the side film to adjust lower.
5, the above exclusion points also need to match the material temperature, equipment, water metering pump, external forces and the surrounding environment and other factors.
Silicone oil has excellent heat resistance, electrical insulation, weather resistance, hydrophobicity, physiological inertness and small surface tension, in addition to low viscosity temperature coefficient, high resistance to compression) Some varieties also have the performance of radiation resistance.
Silicone oil has many special properties, such as anti-oxidation, high flash point, small volatility, non-corrosive to metals, non-toxic, etc.
Basic Classification
By chemical structure, there are methyl silicone oil, ethyl silicone oil, phenyl silicone oil, methyl hydrogen-containing silicone oil, methyl phenyl silicone oil, methyl chlorophenyl silicone oil, methyl ethoxy silicone oil, methyl trifluoropropyl silicone oil, methyl vinyl silicone oil, methyl hydroxy silicone oil, ethyl hydrogen-containing silicone oil, hydroxy hydrogen-containing silicone oil, cyanogen-containing silicone oil, etc.
By application, there are damping silicone oil, diffusion pump silicone oil, hydraulic oil, insulating oil, heat transfer oil, brake oil, etc.
Main Applications
Commonly used as high-grade lubricant, anti-shock oil, insulating oil, defoamer, mold release agent, polishing agent and vacuum diffusion pump oil, etc. Among all kinds of silicone oil, methyl silicone oil is the most widely used and is the most important variety of silicone oil, followed by methyl phenyl silicone oil. In addition, there are also ethyl silicone oil, methyl phenyl silicone oil, silicone oil containing nitrile, etc. Various functional silicone fluids and modified silicone fluids are mainly used for special purposes.
Advantages and disadvantages
Advantages (1) Excellent shear stability, has the function of absorbing vibration and preventing vibration propagation, and can be used as vibration damping fluid. (2) Excellent thermal oxidation stability, such as thermal decomposition temperature >300℃, small evaporation loss (150℃, 30 days, evaporation loss is only 2%), oxidation test (200℃, 72h), small change in viscosity and acid value. (3) excellent electrical insulation, volume resistance, etc. does not change in the range of room temperature ~ 130 ℃ (but the oil can not contain water). (4) It is a non-toxic and low foaming, strong anti-foaming oil, can be used as antifoaming agent, etc. (5) The viscosity and temperature performance is the best among liquid lubricants, and the viscosity changes little in the wide temperature range. Its freezing point is generally less than -50℃, some of them are as high as -70℃, and the appearance and viscosity of the oil do not change when stored for a long time at low temperature.
Disadvantages
(1) Small surface tension (easy to leak from the machine).
(2) Large gas solubility (difficult to design gas seal device)
(3) Large coefficient of thermal expansion of silicone oil (may cause overpressure problem).
(4) The lubricity of silicone oil is poor, especially for the lubrication of the steel-steel friction sub.
(5) A certain degree of hygroscopicity (after the water content is higher than 100×10-6, the electrical performance drops sharply)
Application areas
Silicone oil is used in a wide range of applications, not only as a special material for aviation, cutting-edge technology and military technology sectors, but also for various sectors of the national economy, and its applications have been expanded to include: construction, electrical and electronics, textiles, automobiles, machinery, leather and paper, chemical and light industry, metals and paints, medicine and medical treatment, etc.
The main applications of silicone oil and its derivatives are: de-filming agent, shock absorbing oil, dielectric oil, hydraulic oil, heat transfer oil, diffusion pump oil, defoamer, lubricant, hydrophobic agent, paint additive, polishing agent, cosmetic and daily life product additive, surfactant, particle and fiber treatment agent, silicone grease, flocculant.
