Amidine catalyst for curable compositions
AssigneeSika Technology AG
InventorsRita Cannas, Urs Burckhardt
Life of this patent
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Abstract
The present invention relates to an amidine of the formula (I) and its use as a catalyst for crosslinking a curable composition. The amidine of the formula (I) contains at least one aliphatic amidine group. It is substantially odorless and nonvolatile at room temperature and accelerates the crosslinking of curable compositions very efficiently, without impairing the storage stability of the compositions. It is particularly suitable for compositions based on polymers containing silane groups, with which it is compatible, as a result of which such compositions do not have a tendency to separation or migration or evaporation of the catalyst.
Claims12
A method comprising applying as catalyst for the crosslinking of a curable composition an amidine of the formula (I)
- [QrLQ′-Z]p (I)
- wherein p is an integer from 1 to 6 and r is an integer from 0 to 5, where (p+r) is an integer from 1 to 6,
- L is a (p+r)-valent hydrocarbyl radical having an average molecular weight in the range from 15 to 20 000 g/mol, optionally having heteroatoms,
- or, in the case that r=0 and p=1, may also be a hydrogen radical,
- Q is a reactive group selected from glycidoxy, N-aziridinyl, (meth)acrylate, (meth)acrylamide, (meth)acrylonitrile, maleate, maleamide, maleimide, fumarate, fumaramide, itaconate, itaconamide, crotonate and crotonamide,
- Q′ is a divalent connecting unit formed from the reaction of a reactive Q group with HZ, and Z is an aliphatic amidine group bonded via a nitrogen atom,
- wherein every Z is separated from every other Z by at least 2 carbon atoms,
- and wherein, in the case that r=0 and p=1 and of (meth)acrylamide or maleamide or fumaramide or itaconamide or crotonamide as reactive Q group, L and Q′ may also together be a monovalent hydrocarbyl radical having 5 to 20 carbon atoms and having heteroatoms in the form of amide groups and optionally ether or ester groups.
A curable composition comprising at least one amidine of the formula (I) below and at least one polymer containing silane groups,
- [QrLQ′-Z]p (I)
- wherein p is an integer from 1 to 6 and r is an integer from 0 to 5, where (p+r) is an integer from 1 to 6,
- L is a (p+r)-valent hydrocarbyl radical having an average molecular weight in the range from 15 to 20 000 g/mol, optionally having heteroatoms,
- or, in the case that r=0 and p=1, may also be a hydrogen radical,
- Q is a reactive group selected from glycidoxy, N-aziridinyl, (meth)acrylate, (meth)acrylamide, (meth)acrylonitrile, maleate, maleamide, maleimide, fumarate, fumaramide, itaconate, itaconamide, crotonate and crotonamide,
- Q′ is a divalent connecting unit formed from the reaction of a reactive Q group with HZ, and Z is an aliphatic amidine group bonded via a nitrogen atom,
- wherein every Z is separated from every other Z by at least 2 carbon atoms,
- and wherein, in the case that r=0 and p=1 and of (meth)acrylamide or maleamide or fumaramide or itaconamide or crotonamide as reactive Q group, L and Q′ may also together be a monovalent hydrocarbyl radical having 5 to 20 carbon atoms and having heteroatoms in the form of amide groups and optionally ether or ester groups.
Dependencies are inferred from the claim text.