With the rapid development of the world economy, people's industrial and living standards continue to improve, energy consumption has increased significantly, and energy problems have become increasingly prominent, which is seriously inconsistent with China's current energy conservation and emission reduction, green environmental protection and other policy requirements. Therefore, energy conservation and development of new energy are particularly important at this stage.(
Rigid polyurethane foam is widely used in cold storage, refrigerators, aviation, petroleum, automobile and other fields because of its advantages of light weight, high specific strength, low thermal conductivity and good dimensional stability. Rigid polyurethane foam is mainly composed of isocyanates, polyether polyols, catalysts, foam stabilizers, flame retardants, foaming agents and other materials. It changes the proportion of various raw materials and various auxiliaries or types of materials, and has great influence on the final performance of the foam.(
Foam stabilizer can emulsify foamed raw materials and stabilize foam, so as to make the foams even and delicate, and improve the quality of foam and thermal insulation properties of materials. By using suitable foam stabilizer, the thermal conductivity and surface defects of polyurethane rigid foam can be reduced. To a certain extent, it can reduce the energy consumption of materials and is one of the ways to slow down energy shortage.
According to the current situation of polyurethane rigid foam Market, OSIC has introduced ultra-low defect and low k value rigid foam organic silicone oil ur-16916. Compared with imported product B-8, OSIC rigid foam organic silicone oil ur-16916 can not only improve the surface defects of polyurethane rigid foam, but also reduce the thermal conductivity of polyurethane rigid foam. It can be used in refrigerators, refrigerators, plates, etc Thermal insulation field such as spraying.
1. Experimental part
1.1 main raw materials
Polyether polyol a, polyether polyol B, polyether polyol C, Jurong Ningwu new materials Co., Ltd;Pc-5, pc-8, pc-41, air chemical products company; Organic silicon foam stabilizer ur-16916, Jiangsu OSiC Material Technology Co., Ltd; Imported silicone foam stabilizer B-8;Foaming agent cyclopentane, Foshan Meilong cyclopentane Chemical Co., Ltd;Pm-200, Wanhua Chemical Group Co., Ltd. All above are industrial grade.
1.2 instruments and equipment
Fox-200 thermal conductivity meter, laser comp, USA; High speed mixer, pendraulik, Germany;L-mold, climbing, customized;Hy-0580 universal tester, Shanghai Hengyi Precision Instrument Co., Ltd.
1.3 evaluation of formulation and foam preparation methods
One step method was used to mix the raw materials according to the design formula. The crude MDI was poured into the polyether polyol at a certain rate, stirring at 10 s (3000 r/min) at high speed, poured into the mold or freely foamed, forming polyurethane rigid foam, and the foam was cooked at 24 h at room temperature to test the physical properties. The basic formula is as follows:
|Dosage / portion
|Mixed polyether polyol
1.4 test standard
Test foam density according to GB/T 6343-2009 standard. Test the thermal conductivity of foam according to GB/T 10295-2009 standard. Test foam compression strength according to GB/T 8813-2008 standard; Foam size stability is tested according to GB/T 8811-2008 standard.
Mobility: pour the foaming fluid into a special foam cup, seal the bottom port, so that the foam will climb up and the executives will rise. The foam height H (CM) and the foam quality m (g) in the tube were measured, and the ratio H/m indicated the flow index (cm/g).
2. Results and discussion
2.1 reactivity and density
The foaming time and foam density of UR-16916 and B-8 were compared through free foaming and pouring into L mold. The results are as follows:
Free bubble density
|Start / S
|Wire drawing / S
|Non stick / S
It can be seen from the above table that the time of starting, drawing and non sticking hands of UR-16916 and B-8 is basically the same. The density of free foam and the density of foam filling are basically not different, indicating that the reactivity of UR-16916 and B-8 is basically the same.
2.2. Composite stability
Polyether polyol, catalyst, foaming agent and other raw materials were mixed with ur-16916 according to a certain proportion to form a composite. The composite was placed at room temperature to observe its stability, as shown in the figure below:
After 6 months of storage, the mixture was clear and not layered, indicating that ur-16916 had good compatibility and high stability.
2.3 surface defects
By foaming in the L mold, remove the 0.5-1.5 cm from the foam skin and observe the surface defects of the foam. The surface defects of foam prepared by UR-16916 and B-8 are shown in Figure 2.
It can be seen from Figure 2 that the positive and negative surface defects of the foam prepared by UR-16916 are obviously less than B-8, and the location of defects is relatively high, which indicates that the surface property of UR-16916 is better than B-8.
2.4 thermal conductivity
Table 3 is the thermal conductivity of foam prepared by UR-16916 and B-8:
|Thermal conductivity / MW / (m · K)
The thermal conductivity of ur-16916 is 21.72 MW / (m · K), which is 0.11 MW / (m · K) lower than that of B-8, indicating that the thermal insulation effect of ur-16916 is slightly better than that of B-8.
2.5 other properties
Table 4 is a comparison of other properties such as compressive strength, anisotropy, fluidity and dimensional stability of foams prepared by UR-16916 and B-8.
|Dimensional stability /%
|Compressive strength / kPa
The size change rate of foam prepared by UR-16916 and B-8 was -0.41%, -0.50%, -0.39% and -0.53% at 120 and -30, respectively. The foam did not shrink, and the rate of change in size was basically the same, indicating that the size stability of UR-16916 and B-8 was basically the same.
The compressive strength of UR-16916 prepared in two directions parallel and vertical is 168 kPa and 154 kPa respectively, and the anisotropy is 0.92.The compressive strength of B-8 prepared in two directions parallel and vertical is 168 kPa and 153 kPa respectively, and the anisotropy is 0.91.
The fluidity, thermal conductivity, compressive strength, dimensional stability and surface defects of OSIC rigid foam silicone oil UR-16916 and imported product B-8 were compared
(1) the size stability, fluidity and compressive strength of foams prepared by UR-16916 and B-8 are basically the same.
(2) the thermal conductivity of the foam prepared by UR-16916 is slightly lower than that of B-8, and the thermal insulation effect is slightly better.
(3) the surface defects of foams prepared by UR-16916 are obviously better than those of B-8.