1422884 Polyurethanes BAYER AG 3 Aug 1973 [5 Aug 1972] 36958/73 Heading C3R Polyurethanes which are cross-linked via allophanate and/or bivret and/or uretone imine groups may be linearized by reaction with an organic polyisocyanate in the presence of a polar solvent and at a temperature of 90‹ to 200‹ C. The resulting products are macropolyisocyanates which retain the urethane and optionally urea groups of the starting polyurethane. These macropolyisocyanates may be modified by reaction with aminoalkyl alkoxysilanes and the modified products so produced reacted with atmospheric moisture to introduce siloxane bridges into the molecule. The process may be applied to polyurethane waste, e.g. in the form of elastomers, foams, films, microporous foils and elastomer threads. Suitably the polyisocyanate is used in amounts of 0À8 to 10% by weight based on the polyurethane to be linearized. Solvents for the process include dimethylformamide, diethylformamide, dimethylacetamide, tetramethyl urea, dimethyl sulphoxide, N-methylpyrrolidone, ethylene glycol carbonate, caprolactone and butyrolactone. The aminoalkyl alkoxysiloxane may be monofunctional or bifunctional with respect to isocyanate groups. In a typical example (1) a polyurethane elastomer derived from a polyester, 4,4SP1/SP-diphenylmethane diisocyanate and butane - 1,4 - diol at an NCO/OH ratio of 1À066 is linearized with isophorone diisocyanate in dimethylformamide at a temperature of 130‹ C. The resulting macropolyisocyanate is reacted with a silane of the formula to form a product which is cross-linked by atmospheric moisture by way of siloxane groups.
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机译:1422884聚氨酯BAYER AG 1973年8月3日[1972年8月5日]标题C3R通过脲基甲酸酯和/或丁二酸酯和/或脲醛亚胺基交联的聚氨酯可通过与有机多异氰酸酯在极性存在下反应来线性化在90℃至200℃的温度下为溶剂。所得产物为大聚异氰酸酯,其保留起始聚氨酯的氨基甲酸酯和任选的脲基。这些大分子多异氰酸酯可通过与氨基烷基烷氧基硅烷反应而被改性,并且如此产生的改性产物与大气中的水分反应以将硅氧烷桥引入分子中。该方法可以应用于聚氨酯废料,例如废料。以弹性体,泡沫,薄膜,微孔箔和弹性体线的形式存在。适当地,基于待线性化的聚氨酯,聚异氰酸酯的用量为0-8重量%。该方法的溶剂包括二甲基甲酰胺,二乙基甲酰胺,二甲基乙酰胺,四甲基脲,二甲基亚砜,N-甲基吡咯烷酮,碳酸乙二醇酯,己内酯和丁内酯。氨基烷基烷氧基硅氧烷相对于异氰酸酯基可以是单官能或双官能的。在典型示例(1)中,将NCO / OH比为1‑066的聚酯4,4 1 SP>-二苯基甲烷二异氰酸酯和1,4-丁二醇丁二醇衍生的聚氨酯弹性体与异佛尔酮二异氰酸酯线性化在130℃的温度下,在二甲基甲酰胺中。所得的大聚异氰酸酯与下式的硅烷反应,形成产物,该产物被大气水分通过硅氧烷基团交联。
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