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Oct 30, 2020
Background technique:
The existing silicone surfactants used to prepare polyurethane rigid foams all use hydrogen-containing silicone oil and allyl alcohol as the initiator, and the allyl polyether reaction of the alkylation reaction of ethylene oxide and propylene oxide The allyl polyether, which is usually used to prepare the silicone surfactant of polyurethane rigid foam, is an unblocked polyether.
Although the acetyl-terminated allyl polyether has a high end-capping rate, some products can reach a blocking rate of 98%, but the silicone surfactant prepared by this allyl polyether is mixed with water and amine catalysts It will appear milky white, opaque, and will deteriorate immediately after mixing, which will affect the preparation of rigid polyurethane foam.
The end-capping rate of alkyl-terminated allyl polyethers is generally less than 95%, and the alkyl-terminated silicone surfactants have poor compatibility with the polyurethane composition.
Technical realization elements:
The purpose of the present invention is to provide a method for preparing silicone surfactants for preparing polyurethane rigid foams. The method for preparing silicone surfactants for preparing polyurethane rigid foams has to solve the existing problems. The technical problem of silicone surfactants mixed with water and amine catalysts will appear milky white and opaque. The technical problem of deterioration will occur immediately after mixing. At the same time, the technical problem of poor compatibility with polyurethane composite materials should be solved.
The present invention provides a preparation method of organosilicon surfactant for preparing polyurethane rigid foam, which comprises the following steps:
1) The monohydroxy polyether using monohydric alcohol or alkyl alcohol ether as the initiator reacts with allyl chloride or methallyl chloride to obtain allyl polyoxyethylene ether or polyoxyethylene ether; In the allyl polyoxyethylene ether or polyoxyethylene ether, the mole percentage of ethylene oxide group and propylene oxide group is 40-50%: 50-60%;
2) Weigh allyl polyoxyethylene ether or polyoxyethylene ether and low-hydrogen polysiloxane according to parts by weight. The hydrogen content of the low-hydrogen polysiloxane is 0.1-0.2%. The weight ratio of allyl polyoxyethylene ether or polyoxyethylene ether and low hydrogen-containing polysiloxane is 300-400:100-200;
3) First add allyl polyoxyethylene ether or polyoxyethylene ether to a container, then add the low-hydrogen polysiloxane, start stirring, heat to 75-85°C, add the catalyst chloroplatinic acid ethanol solution, After 2 to 4 hours of copolymerization, a clear and transparent light yellow liquid is obtained, which is an organosilicon copolymer surfactant.
Further, the monohydric alcohol or alkyl alcohol ether is any one of butanol butyl ether, ethylene glycol butyl ether, ethylene glycol propyl ether, or triethylene glycol methyl ether.
Specifically, the hydrogen content refers to the mass percentage of hydrogen in the low-hydrogen polysiloxane.
Further, in step 2), after adding the chloroplatinic acid ethanol solution, the concentration of chloroplatinic acid in the entire reaction system is 15 ppm.
Further, the residual allyl chloride or methallyl chloride in step 1) is removed by vacuum.
The present invention uses monohydric alcohol or alkyl alcohol ether as the starting agent to react with allyl chloride or methallyl chloride to prepare a monohydroxy polyether to prepare a 100% blocked allyl polyether, and then use the alkene The propyl polyether reacts with the low hydrogen-containing polysiloxane to prepare the organosilicon surfactant. The invention prepared is a hydroxyl-free organosilicon surfactant for polyurethane rigid foam. This type of organic silicon surfactant can improve the voids of the polyurethane rigid foam and increase the fluidity of the foam.
Compared with the prior art, the technical effect of the present invention is positive and obvious. The present invention can prepare a 100% full-blocking rate of silicone surfactant; meanwhile, the silicone surfactant of the present invention can be mixed with water to realize self-emulsification and has a transparent appearance; and the silicone surfactant of the present invention can improve polyurethane The skin of rigid foam.