Why is multi stage dilution used in the post production process of resin?

Guess, the synthesis kettle can't fit, for example, the synthesis kettle is 500L, and the alkyd resin in it has 300L, which is diluted to 10%, that is, 3000L, so it can only be transferred to the dilution kettle for dilution.

？Resin diluents include reactive diluents and non-reactive diluents, and reactive diluents contain epoxy groups in the middle, which can participate in the curing reaction and form a three-dimensional cross-linked structure. Inactive diluents do not contain epoxy groups and cannot participate in curing reactions.

Alcohols (such as alcohol), esters (such as ethyl acetate, dibutyl phthalate), ketones (such as acetone), solvent gasoline, toluene, etc. can be used as inactive diluents for epoxy resins. There are also many kinds of reactive resin diluents, including monofunctional, difunctional, trifunctional, and multifunctional (more than four-functional) reactive diluents, which generally slow down the curing time of epoxy resin and reduce temperature resistance and post-curing strength. Although the addition of difunctional groups has little effect on the properties of resin compositions, such organic substances may have a higher viscosity

Poor unit dilution, or low reactivity of lipid epoxides, has led to more attention being paid to the development of monofunctional reactive diluents. At present, the commonly used monofunctional reactive diluents are propylene oxide butyl ether (501' for short) and propylene oxide phenyl ether (690').501.

It is a low-molecular weight straight-chain structure, which has a great impact on the thermal performance of the cured matter after addition, and although 690* can overcome this weakness to a certain extent due to the benzene ring contained in the molecule, it is also unpopular because of its high toxicity and allergy when used. To this end, foreign countries have successively used mixed cresol, a by-product of coal preparations, to develop cresol glycidyl ether active epoxy diluents with good performance, low toxicity and low cost.

The piston compressor adopts the process of multi-stage compression and inter-stage cooling mainly to reduce the compression ratio, because the compressor from the intake to the final exhaust, if the multi-stage compression is not taken, the compression ratio will be very large, the discharge temperature will be very high, and the equipment will be damaged because of the high temperature, so the multi-stage compression process will be adopted in the design of the high-pressure compressor. In the working process of the compressor, due to the increase in exhaust pressure, the internal energy of the gas changes, causing the temperature to rise, so in order to avoid the high-temperature gas entering the next cylinder to be compressed and pressurized, causing over-temperature operation and damaging the equipment, a cooler is usually set up between stages to cool down.

Advantages of multi-stage compression;

1.Save power consumption.

Due to the graded compression, the gas heats up after compression, but after intermediate cooling, the air temperature of the next stage of inhalation can be reduced to close to the original temperature, the gas is compressed by one stage, and then compressed by isobaric compression, and three points can fall on the isotherm after cooling, so the area of multi-stage compression work under the same pressure is less than that of single compression. The more stages there are, the more power savings there are, and the closer it is to isothermal compression.

2.Improve the volume utilization of cylinders.

It is inevitable that there is a clearance volume in the cylinder, when the higher the number of stages, the higher the pressure of the expulsion, and the volume occupied by the residual gas in the residual clearance volume after expansion is also larger, so that the volume coefficient is reduced by multi-stage compression is to make each set of compression ratio decrease, and the volume coefficient is increased, so as to improve the volume utilization rate of the cylinder.

3.Reduce the exhaust temperature.

The temperature of the exhaust gas of the compressor increases with the increase of the compression ratio, the higher the compression coin, the higher the exhaust temperature, but the excessively high exhaust temperature is often not allowed, which is due to; In the oil-lubricated compressor, the lubricating oil temperature will reduce the viscosity and aggravate the wear, when the temperature rises too high, it is easy to form carbon deposits in the cylinder and the valve, aggravate the wear, and even happen, for various reasons, the exhaust temperature is greatly limited, so multi-stage compression must be used to reduce the exhaust temperature.

4.Reduces the gas forces acting on the piston rod.

When the compression is relatively high and the single compression is adopted, the cylinder diameter is larger, there is a higher gas final pressure acting on the larger piston area, and the gas on the piston is larger, if the multi-stage compression is adopted, the gas force acting on the piston can be greatly reduced, so it is possible to make the mechanism lightweight, and the mechanical efficiency is improved.

5.Of course, multi-stage compression is not about the more stages the better, because the more stages. The compressor structure tends to be complex, and the size, weight and cost have to increase; As the number of gas passages increases, the pressure loss of valves and management increases, so sometimes the economy decreases when the number of stages increases, and the chance of failure increases due to the increase in friction, and the mechanical efficiency will also decrease.

disadvantages of multi-stage compression;

increased mechanical complexity of compressors;

increased resistance loss in pipelines, equipment, and valves;

The cost of manufacturing and running costs have increased significantly.

The multi-stage compression process of the piston compressor is mainly to reduce the compression ratio, because the compressor from the intake to the final exhaust, if the multi-stage compression is not taken, the compression ratio will be very large, the exhaust temperature will be very high, the equipment will be damaged because of the high temperature, and because the energy consumption is increased due to the high compression ratio, in order to avoid the occurrence of these two situations, the multi-stage compression process will be adopted in the design of the high-pressure compressor.