Polyurethane composite foaming agent containing dialkyl carbonate

Abstract

The invention discloses a polyurethane composite foaming agent containing dialkyl carbonate, the composite foaming agent mainly comprises the following components: component (FA) a first blowing agent, the first foaming agent comprises (fa1) a physical blowing agent having a lower boiling point, the physical foaming agent with the lower boiling point of the component (fa1) is selected from one ormore of cyclopentane, HCFC-141b, HFC-245fa, HFC-365mfc, LBA (monochlorotrifluoropropene), hexafluorobutene and trans-dichloroethylene, and a di(C1-C2 alkyl)carbonate of component (FB) as a second blowing agent, the mass ratio of component (FA) to component (FB) in the composite blowing agent is 0.2-6: 1. The composite foaming agent can eliminate the phenomenon of local foam core burning in the existing foam material preparation method. Additionally, the composite foaming agent may also contain fluorohydrocarbons (such as R134a, R125, R152a, R32, R227 ea, etc.) having a FC boiling point of -70DEG C to 0 DEG C to promote a polyurethane nucleation reaction and improve foam insulation performance.

Description

technical field [0001] The present invention relates to a kind of containing dialkyl carbonate (being two (C carbonate) 1 -C 2 Alkyl) ester) and a polyurethane composite foaming agent and a foamable composition of a physical foaming agent with a lower boiling point, belonging to the technical field of polyurethane foam preparation. Background technique [0002] As a new polymer material, polyurethane rigid foam is light in weight, high in strength and has extremely low thermal conductivity. It is a high-quality thermal insulation material and is widely used in refrigeration and thermal insulation, building energy saving, solar energy, automobiles, refrigerators and freezers and other home appliances. and other industries. The most important raw material in the production of rigid polyurethane foam is the blowing agent. At present, these blowing agents are halogen-containing hydrocarbons except for alkane blowing agents. Due to their damage to the atmospheric ozone layer, ...

AI Technical Summary

Problems solved by technology

However, this blowing agent is not suitable for the preparation of polyurethane foam

[0013] The prior art discloses supercritical carbon dioxide or liquid carbon dioxide directly as blowing agent, but the carbon dioxide in supercritical state or liquid state needs to be processed at low temperature and high pressure (tens of storage under one atmosphere), the operation of the foaming reaction is difficult to control

[0014]Although alkane foaming agents are more environmentally friendly, they still have low flash point, low boiling point, and the risk of being extremely explosive, and transportation and storage are extremely inconvenient. In addition, Like cyclopentane, which is widely used at present, its GWP (global warming index potential value) is high and other disadvantages

[0015] In the process of preparing polyurethane foam, especially in the process of polyurethane spraying, bulk foam preparation, etc., the reaction between polyisocyanate and polymer polyol is highly Exothermic reaction, leading to local (for example central) overheating, which in turn causes localized core burning or scorching to occur often in the foam formed, yellowing or even blackening of the color of the foam and reduction in the produced foam. Strength Properties and Thermal Insulation Properties of Foam Materials

[0016] In addition, in the process of preparing polyurethane foam materials, especially in the process of polyurethane household appliances, board foam preparation, etc., the reaction between polyisocyanate and polymer polyol is Slower, poor nucleation during the foam milking process leads to uneven cell distribution of the foam material, which in turn makes the formed foam material often have local cell inhomogeneity, poor dimensional stability of the foam material and reduced strength of the prepared foam material Properties and insulation properties

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