Silante terminated polyurethane

A curable, alkoxysilane-functional polyether urethane composition formed by combining

• a) a first silane terminated polyurethane prepared by reacting:
• i) at least one mono-functional compound selected from the group consisting of polyethers, amines, amine terminated polyethers, or polysulfides having a hydroxyl, amine or thiol functional group, and mixtures thereof, having a number average molecular weight of from 500 to 20,000, and having a structure according to formula (III):
• R2-(-Z-CR3n-)m-Z-H (III)
• wherein R2 represents a C1-C22 linear branched or cyclic alkyl, aryl, aralkyl, alkaryl, or alkenyl group;
• each occurrence of R3 is independently a H, methyl or ethyl group, n is from 1 to 5, m is from 10 to 1,000;
• and each occurrence of Z is independently an O, S or —NR4-group, wherein R4 is an H, methyl, ethyl, propyl, n-butyl or t-butyl group with
• ii) an isocyanate component containing two isocyanate groups, the reaction product of i) and ii) reacted with
• iii) a compound containing an isocyanate-reactive group and at least one reactive silane group in which at least 10 mole % of component iii) is a compound corresponding to formula (I)
• wherein
• X represents identical or different organic groups which are inert to isocyanate groups below 100° C., provided that at least two of these groups are alkoxy or acyloxy groups,
• Y represents a linear or branched alkylene group containing 1 to 8 carbon atoms and
• R1 represents an organic group which is inert to isocyanate groups at a temperature of 100° C. or a group corresponding to formula II
• —Y—Si—(X)3 (II)
• to form a moisture-curable, alkoxysilane-functional polyether urethane;
• and
• b) a second silane terminated polyurethane prepared by reacting:
• i) n-propanol or n-butanol or t-butanol with
• ii) an isocyanate component containing two isocyanate groups, the reaction product of i) and ii) reacted with
• iii) a compound containing an isocyanate-reactive group and at least one reactive silane groups corresponding to formula (I) as defined above.