Views:6 Author:Site Editor Publish Time: 2020-08-29 Origin:Site
During the polyurethane foaming process, the foam has shrinkage, crispness, too soft, heartburn, cracking, smoke and other problems. How to analyze the causes.
During the polyurethane foaming process, affected by the construction conditions, foaming equipment, construction technology and ambient temperature, various abnormal phenomena will occur, which will eventually affect bubble quality issues. How to solve the shrinkage, crispness, too soft, heartburn, cracking and smoke during the polyurethane foaming process?
The following material A represents polyurethane white material, that is, combined polyether; material B represents polyurethane black material, that is, polymeric MDI.
1. Material A and B do not foam after mixing: ①The temperature of the material is low; ②The distribution ratio of the two groups is inaccurate ③The catalyst of material A is missing; ④The quality of material B is poor; material A is missing a blowing agent.
⒉. Polyurethane rigid foam shrinkage: ① There are many components in the A material, which reduces the strength of the polyurethane rigid foam and causes shrinkage; ② The material and liquid in the spray gun are mixed unevenly, the spray air is too small, or the material.
The viscosity of the material is too large; ③ solidification is too fast, and more closed cells are formed; ④ the gas expands and shrinks and deforms.
3. Polyurethane hard foam is crispy: ①B material has too many components; ②Too much moisture; ③Working surface temperature is too low; ④B material has a large acid value and contains many impurities; A material flame retardant added amount excessive.
4. The rigid polyurethane foam is too soft and the maturation is too slow: ①The amount of material in the B material is small; ②The tin catalyst in the A material is too little; ③The air temperature, material temperature and blanking surface temperature are low.
5. Polyurethane rigid foam collapse: ①The foaming gas is generated too fast, and the amount of amine catalyst in material A should be reduced; ②The foam stabilizer in material A is invalid and alkaline; ③The catalyst is invalid, otherwise, the tin catalyst in material A should be added; ④The acid value in the raw material is large.
6. Thick polyurethane hard foam cells: ①The foam leveling agent in material A is invalid or missing; ②There is too much water (water in the foaming agent or polyether); ③A. The mixing of materials is uneven uniformity; ④B material has low purity, contains total chlorine or high acid value; ⑤The gas generation rate is faster than gel.
7. Rigid polyurethane foam is cracked or core burned: ①The material temperature is high; ②The catalyst of material A is too much; ③The amount of casting at one time is too large, and the foam is too thick; the amount added when making a blowing agent too much; ④There are metal salt impurities in the material.
8. The polyurethane hard foam falls off: ①The spraying working surface has high humidity, which makes the reaction insufficient, and the underlying foam is crisp, brittle, and powdery.②The sprayed working surface is unclean. oily, too much dust.
9. Fumes from rigid polyurethane foam: ①The amount of catalyst in material A is too high; ②The hydroxyl value of polyether in material A is too high; ③the temperature of material is too high, etc.
From the analysis of the above problems, it is known that in addition to objective factors, the A component involves many factors. In actual production, adjust the viscosity, milky time, and foam time, curing time, etc. are mainly to adjust A material.
In the polyurethane foaming process, it is not only the mixing of A and B materials. It is necessary to understand the principle of forming polyurethane rigid foam and the role of each component, integrate all factors, and be targeted.
After analyzing and judging that there are problems, it is not difficult to produce high-quality polyurethane.
Polyurethane foaming machine can process polyether polyol and isocyanate materials to support uniform and qualified foam products, but how to better improve the function of the equipment will be an important prerequisite for improving the quality of foam products. Of course, to process the polyureth
Shandong Hightop Group conducts all-round disinfection work for Aile Kindergarten in Jining High-tech Zone for free The Spring Festival in 2021 is approaching. In order to effectively eliminate the virus and prevent the spread of the epidemic, Shandong Hightop Group launched a public welfare activit
Polyurethane foaming machine is widely used in multi-mode continuous production of rigid and semi-rigid polyurethane products, such as: petrochemical equipment, directly buried pipelines, cold storage, water tanks, meters and other thermal insulation and sound insulation equipment and craft products
As a new coating material, polyurea has changed the concept and cognition of previous coatings by engineers and added new knowledge of coatings. Since the polyurea coating can withstand the full impact of a sledgehammer and the most severe abrasion, it also has satisfactory flexibility. When the obv
What are the reasons for the unstable flow of the variable pump of the multifunctional high-pressure foaming machine? If you want to know, please come and find out with the editor!1. The input port of the variable pump of the multifunctional high-pressure foaming machine is lacking in supply. It may
There are many kinds of fillers used in polyurethane rigid foam, such as expanded graphite, powdered nylon, silica, glass fiber, etc. The filler used in polyurethane foam must be dried before use. When applied to a water foaming system, its moisture content must be measured.
1. The company's equipment has passed CE, ISO9001 quality management system certification, completely independent intellectual property design and production, has declared a number of national invention patents.2. The equipment is small in size, light in weight, low in failure rate, convenient to mo
The key to the construction quality of spraying polyurea lies in the substrate, and the substrate is divided into two types: metal substrate and concrete substrate, but no matter which kind of substrate, we must consider its anti-corrosion and waterproofing. So, what are the ways to deal with the an
Construction efficiency and characteristics of polyurea spray equipmentConstruction characteristics of polyurea spraying equipment: Polyurea spraying equipment is mainly used for spraying of rough spots on the surface of interior and exterior walls of buildings, spraying of commercial mixed polyurea
At present, the advantages of rigid polyurea with its excellent physical and chemical properties and advanced and convenient construction technology in the anti-corrosion application of the outer wall of the pipeline have been highlighted. Compared with 3PE, the rigid polyurea spraying equipment has