Views: 155 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.
I believe that many large-scale enterprise plant owners know, color steel tile room use time is long time to regularly renovate its maintenance. But not insiders may not know is color steel tile room renovation really deep water, different price different specification brand polyurethane spraying eq
Dual-speed sprayer is a breakthrough equipment in the modern spraying field, which realizes the double improvement of spraying efficiency and precision through the innovative dual-mode power system. Its core principle is based on intelligent speed switching and pressure control, which is widely used
In many fields such as industrial protection and building waterproofing, polyurea materials have been widely used for their excellent performance advantages. In order to give full play to the characteristics of polyurea materials, a high-performance spraying equipment is crucial, and the CNMC-A25 po
On March 31, 2025, Hightop Group's housewarming celebration was held in the new headquarters office building at 66 Xinyuan Road, Jining. All Hightop employees, partners and other industry leaders gathered together to witness important milestones in the development of the enterprise and open a new ch
In the era of the booming development of cross-border e-commerce, a piece of good news has added a beautiful color to the commercial map of Shandong Province. Recently, the Shandong Provincial Department of Commerce officially announced the "Shandong Provincial Department of Commerce on the identifi
construction field Thermal insulation: can be used for building roofs, walls, floors and other parts of the thermal insulation treatment, such as in the new residential and commercial buildings of the external wall spraying inorganic fiber wool, can effectively prevent the heat transfer, reduce ener
Recently, Jining Economic Development Zone grandly held the second high-quality development and high-level opening conference. The conference aims to fully implement the spirit of the central and provincial and municipal private enterprises Symposium, summarize the effectiveness of high-quality deve
Polyurethane foam is widely used for its excellent thermal insulation, heat preservation and sealing performance in the fields of building thermal insulation, industrial thermal insulation and many other areas that require sealing and filling. As the key equipment in the construction of polyurethane
Recently, Liu Xiaolin, Secretary of the Party Working Committee and Director of the Management Committee of Jining Economic and Technological Development Zone in Shandong Province, Cai Dahu, Director of the Economic and Technological Development Zone Innovation and Entrepreneurship Center, and relev
Spring Festival does not close, for this year's Spring Festival holiday, CNMC Machinery's Ali International Station store got a good start. We started the year with a salesman, we harvested more than 1.4 million in sales, of which the largest single order reached one million.CNMC Machinery is a subs