Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From reactant having at least one -n=c=x group as well as...
Patent
1990-06-13
1991-11-19
Welsh, Maurice J.
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
From reactant having at least one -n=c=x group as well as...
528 69, 528 76, 528 80, 528 83, 528 85, C08G 1810
Patent
active
050667599
DESCRIPTION:
BRIEF SUMMARY
The invention relates to a process for the preparation of macromonomers which carry at least two hydroxyl groups at one end.
Macromonomers are taken to mean relatively short-chain polymers or oligomers which contain, at one end, functional groups which are capable of polymerization, polyaddition or polycondensation.
Macromonomers are used, in particular, for the preparation of graft copolymers. It is known that polyethers which carry two hydroxyl groups at one end can be employed as macromonomers. Such polyethers are prepared by initiating the polymerization of alkylene oxides using an acetal or ketal which contains a H-acidic group in addition to the acetal or ketal group. After blocking the terminal hydroxyl groups, polyether-1,2- or -1,3-diols are obtained from the resultant reaction products by elimination of the acetal or ketal group (cf., for example, German Offenlegungsschrift 3,025,807).
The above-described process for the preparation of polyethers which can be employed as macromonomers is associated with relatively high costs and is only suitable for the preparation of macromonomers based on polyalkylene oxides.
It would be desirable to have available carboxyl group-carrying macromonomers for the preparation of water-diluteable polymers.
The object of the present invention is to provide a novel process for the preparation of macromonomers which carry an average of at least one carboxyl group and, at one end, at least two hydroxyl groups per molecule.
This object is achieved by a process which comprises prepolymer which has a number average molecular weight of 300 to 3000, preferably 500 to 2000, and contains an average of one terminal hydroxyl or amino group and at least one carboxyl group per molecule with a diisocyanate to form an intermediate containing an average of one terminal isocyanate group and at least one carboxyl group per molecule, and subsequently reacting this intermediate 120 to 300, and contains at least two hydroxyl groups in addition to a group which is reactive to isocyanate groups, to form a macromonomer which carries an average of at least one carboxyl group and, at one end, at least two hydroxyl groups per molecule.
The advantages achieved by the invention are essentially that the process according to the invention makes possible the preparation of carboxyl group-carrying macromonomers in a simple manner and that the process according to the invention can be carried out at relatively low expense with a very wide variety of readily accessible prepolymers.
The process according to the invention is a two-step process. In the first step, a polyester, polyether, polyurethane, polyurea or polyamide prepolymer which has a number average molecular weight of 300 to 3000, preferably 500 to 2000, and contains an average of one terminal hydroxyl or amino group and at least one carboxyl group per molecule is reacted with a diisocyanate to form an intermediate containing an average of one terminal isocyanate group and at least one carboxyl group per molecule.
Polyesters which are suitable as prepolymers can be obtained, for example, by polycondensing dialcohols and dicarboxylic acids or reactive dialcohol or dicarboxylic acid derivatives (such as, for example, dicarboxylic anhydrides) by methods which are generally well-known, the dialcohol component and the dicarboxylic acid component being employed in a molar ratio of 1:1 and the polycondensation reaction being terminated when the molecular weight desired is reached. In order to determine the molecular weight of a polyester, simple determination of the acid number is sufficient. The molecular weight can be calculated using the formula ##EQU1## (M=number average molecular weight, AN=acid number). The polycondensation reaction can be terminated, for example, by cooling the reaction batch.
Aliphatic, cycloaliphatic (saturated or unsaturated) and/or aromatic dicarboxylic acids preferably having 2 to 14, particularly preferably 4 to 12, carbon atoms per molecule or the esterification-capable derivatives thereof (for example anhydrides or est
Dobbelstein Arnold
Hille Hans-Dieter
BASF Lacke & Farben AG
Welsh Maurice J.
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