Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Cellular products or processes of preparing a cellular...
Patent
1987-09-02
1988-09-13
Welsh, Maurice J.
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Cellular products or processes of preparing a cellular...
521112, 521118, 521129, 521131, 521132, 521137, C08G 1814
Patent
active
047710829
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE ART
The present invention relates to medicine and more particularly to polyurethane foam composition for immobilization traumatology.
PRIOR ART
Known is the art is a composition for preparing an immobilizing foam material based on polyurethane (U.S. Pat. No. 4,947,307, 1960, cl. 128-90), said composition containing polyester with hydroxyl groups, hexamethylenediisocyanate, tertiary amine a catalyst, and water as a foaming agent. Such a composition is characterized by a high viscosity of polyester which hinders or makes impossible its use in nonstationary conditions and by considerable heat liberation caused by a high activity of primary hydroxyl groups in polyesters. Considerable heat liberation necessitates (to avoid burns) the use of polyesters with a low content of hydroxyl groups and this fact, in its turn, decreases the rigidity of polyurethane foam.
Also known in the art is a composition (U.S. Pat. No. 3,301,252, 1967, cl. 128-90) for preparing a rigid immobilizing foam material containing aromatic polyether which is a product of condensation of 1.1.3-hydroxyphenylpropane and propylene oxide with a hydroxyl number of about 380, polyphenylmethanepolyisocyanate containing from 40 to 60 mass % of 4,4-diphenylmethanediisocyanate, trichlorofluoromethane as a foaming agent, 1-methyl-4-dimethylaminoethylpiperazine as a catalyst, and block copolymer of siloxane and oxyalkylene as a foam stabilizer.
The disadvantages of this composition reside in a high viscosity of aromatic polyether, high temperature of the formation of polyurethane foam, and toxicity of the catalyst.
Likewise known in the art is a composition (The Author's Certificate of the USSR No. 433181, 1971, cl. C 08 G 18/14) containing as a hydroxil-containing compound a mixture of N,N,N',N'-tetraoxypropylethylenediamine and polyether based xylite in a ratio of 1:9-4:6, respectively, polyisocyanate, and a foaming agent.
The above composition is also disadvantageous in that the temperature of formation of polyurethane foam is high.
Also known in the art is a composition (The Author's Certificate of the USSR No. 990213, 1975, cl. A 61 F 1/00) containing the following components (mass %): groups in polyester equal to 1:1: the balance.
As a hydroxyl-containing polyester use is made of the products of oxyalkylation of polyatomic alcohols and as a foam stabilizer-of an organosilicon compound. The composition ensures a required rate of the formation of polyurethane foam and of hardening at lowered temperature but high heat liberation calls for the use of heat insulating fillers to avoid burning the skin of the patient.
DISCLOSURE OF THE INVENTION
The main object of the invention is to prepare a polyurethane foam composition by introducing a new component and changing a qualitative ratio of the initial components, said composition having a low foaming temperature and improved water resistance which rules out a possible burning the skin of the patient.
Said object is accomplished by that the propoposed polyurethane foam composition for immobilization in traumatology containing hydroxyl-containing polyester, a catalyst, a foaming agent, a foam srabilizer, and polyisocyanate in the amount ensuring the ratio of the isocyanate and hydroxyl groups of the polyester equal to 1:1, according to the invention, contains additionally a low-molecular polyolefin at a following ratio of the initial component (mass %): polyester equal to 1:1: the balance.
The introduction of a low-molecular polyolefin in amount 20-30 mass % into the composition decreases heat liberation upon hardening the foam material.
As a low molecular polyolefin said composition contains preferably vaseline oil or solid paraffin, as a hydroxyl-containing polyester--the product of oxyalkylation of polyatomic alcohol with alkylene oxide.
The proposed composition contains preferably hydroxyl-containing tertiary amine as a catalyst, trichlorofluoromethane as a foaming agent, organosilicon oligomers or the products of their oxyalkylation as a foam stabilizer, and 4,4-diphenylmethanediisoc
REFERENCES:
patent: 2947307 (1960-08-01), Hoppe
patent: 3301252 (1967-01-01), Mahoney
patent: 3674901 (1972-07-01), Shepherd et al.
patent: 4203435 (1980-05-01), Krull et al.
Cherkashin Viktor V.
Davydov Anatoly B.
Lir Irina L.
Ljukevich Igor A.
Scherbak Agnessa S.
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