| 摘要 |
The adducts of formula - HO-(CH2)3-CO-NH-(CH2)n-CH(R)(R') (I) - (R is H or H or CH3, R' is OH or -NH-CO-(CH2)3-OH and n = 1-2), are made by reacting butyrolactone (II) with an amine - X-CH(R)-(CH2)nNH2 - in which X is NH2 or OH at a temp. of 60-100 deg. C. The reaction is carried out e.g. in an inert liq. solvent such as MEK or acetone. - Pref. the wt. ratio polyurethane prepolymer :(I) is 5:1 to 10:1. - (I) are esp. useful as chain extenders for castable polyurethane elastomers, e.g. by mixing a polyurethane prepolymer with the (I) at 70-120 deg. C for not more than ca. 2 mins. and casting the mixt. into a mould. The castings can be demoulded e.g. in 20-60 mins and may be post cured at 70-120 deg. C for ca. 16 hours and opt. conditioned at room temp. and 50% R.H. Prods. are tough and have good resistance to abrasion, oils, solvents, chemicals, etc., useful e.g. as coatings, flexible mechanical couplings, belting, hammer heads, rollers for printing and feed conveying, shock absorber pads, solid tyres and wheels, bumpers, etc. (0/0) USAB- US4448905 A Castable elastomeric compsn. (I) comprises (A) a polyurethane and (B) a cpd. of formula HO-(CH2)3-CO-NH-(CH2)n-CHRR' in which R is H or methyl, R' is OH or -NH-CO-(CH2)3-OH and n is 1 or 2, in a mole ratio of between about 1:1 and about 1:3. Pref. R is H and R' is OH and n is 1; or R is methyl, R' is -NH-CO-(CH2)3-OH and n is 1. (I) is produced by admixing (A) and (B) at between 70 and 120 deg.C pref. for not longer than 2 mins. - Cured prods. are provided of significantly improved tensile and tear strength and elongation properties. - (5pp)
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