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...
Reexamination Certificate
2000-04-28
2002-08-13
Gorr, Rachel (Department: 1711)
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...
C528S059000, C528S073000, C548S215000, C549S374000, C549S453000, C252S182230, C540S467000, C544S088000
Reexamination Certificate
active
06433124
ABSTRACT:
The present invention relates to a compound of the formula I
(reactive polymer) where L is a polymer, XY is a reactive radical which is inert toward NCO groups and which splits off one or more protective groups Y under acidic, neutral or basic conditions and the radical X bears, after Y has been split off, at least two groups which are reactive toward isocyanates. Furthermore, the invention relates to a process for preparing such a polymer and also a polymer polyol which is obtainable by reaction of a polymer of the formula I with an acid or base. The invention likewise relates to a polyaddition product or polycondensation product which can be prepared using a polymer polyol as is obtainable by treatment of a reactive polymer according to the present invention in the neutral, acidic or basic range.
High-functionality structures containing OH and/or NH groups are valuable in polyurethane chemistry, especially for producing polyurethane foams and polyurethane-containing coatings. Here, particular importance is often attached to polyurethane prepolymers which, owing to their generally low viscosity, are frequently used as starting materials for the synthesis of high molecular weight and sometimes crosslinked polyurethane polymers. These prepolymers are particularly important in, for example, the production of surface coatings or of moldings.
In general, polyurethane prepolymers are prepared by reacting polyols or polyamines with at least bifunctional isocyanates, with the polyols or polyamines usually having a functionality of at least about 2. If higher-functional polyurethane prepolymers are desired, there are various but generally unsatisfactory possible methods of preparing them. For example, the polyol used can be a low molecular weight relatively high-functionality polyol which is subsequently reacted with appropriate bifunctional isocyanates to give the prepolymer. Disadvantages of this procedure are that the desired polyurethane polymer has only a low molecular weight and that crosslinked, high molecular weight material is formed as by-product.
Another method is, for example, to extend an appropriate low molecular weight polyol at each OH group by means of a polyaddition or polycondensation reaction. Although this does make it possible to obtain high molecular weight polyols, the products have a large number of polymer chains in each polyol molecule corresponding to their functionality and these polymer chains modify, possibly in an undesirable way, the properties of the polyurethane prepolymer or of the product obtained therefrom.
A further possibility is to modify a linear polymer at the end groups in such a way that, for example, the desired number of OH groups or NH groups at the end of the polymer chain is obtained. To prepare a polyester having two OH groups at the end of each chain, it would be possible, for example, to react a polyester molecule having a COOH group at the end of each chain with an excess of trimethylolpropane so as to give a polyester which bears two OH groups at the end of each chain. However, such a reaction is generally uneconomical since excess material has to be separated from the reaction product. In addition, it is usually not possible to prevent at least part of the reaction products from reacting with the polymer added as starting material and thus leading to chain extension or crosslinking.
Various types of high-functionality structures containing OH and/or NH groups are known from the prior art. Thus, for example, pentaerythritol-, sorbitol- or sucrose-initiated polyether polyols based on ethylene oxide or propylene oxide or mixtures thereof are prior art. Such polyether polyols generally have functionalities of from about 3 to about 6.
WO 93/14147 discloses polyamines which have a dendritic structure. Such products are complicated to prepare, since acrylonitrile is grafted onto an amine in a first reaction step and the nitrile is converted into an amine in a subsequent hydrogenation step. This procedure is repeated a number of times until the desired NH
2
functionality is achieved. However, a disadvantage of these products is that they have only functionalities, OH functionalities or mixed, i.e. OH- and NH-containing, structures are not obtainable in this way.
WO 93/17060 discloses polyester polyols which are formed, for example, by reaction of TMP or pentaerythritol with dimethylolpropionic acid. However, the reaction proceeds very unselectively and highly branched structures are obtained.
DE-A 195 24 045 relates to highly functionalized polyurethanes which are built up from molecules having the functional groups A(B)
n
, where A is an NCO group for a group which reacts with an NCO group, B is an NCO group or a group which reacts with an NCO group, A is reactive toward B and n is a natural number and is at least 2. The structures disclosed can be used for preparing dendritic compounds. A simple process for preparing polymers in which the building up of functionality and the building up of molecular weight are largely decoupled is not disclosed in the document.
There is therefore a need for a process which allows a polymer to be provided in a simple manner with end groups so that the number of end groups per chain end is at least two and essentially no chain extension between the individual polymer molecules takes place. Furthermore, there is a need for compounds which are obtainable by such a process.
It is an object of the present invention to provide a polymeric compound which can be converted by means of a simple chemical reaction into a molecule which has at least two functional groups which are reactive toward NCO groups per molecule. A further object of the invention is to provide a process for preparing such a compound. It is also an object of the invention to provide a simple process for multiplying the number of isocyanate-reactive end groups in polymers which are reactive toward NCO and are free of urethane groups.
We have found that these objects are achieved by a compound of the formula I
as defined in the text below.
The present invention accordingly provides a compound of the formula I
where L is a polymer which is free of urethane groups and has a molecular weight M
n
of at least 300, or any linear or branched sequence of two or more such polymers, A is a substituted or unsubstituted, linear or branched, saturated or unsaturated alkylene group having from 2 to 12 carbon atoms or a substituted or unsubstituted, saturated or unsaturated cycloalkylene group or a substituted or unsubstituted arylene group having from 3 to 18 carbon atoms or an arylene-alkylene group having from 7 to 18 carbon atoms or a heterocyclic group or any linear or branched sequence of two or more of the groups mentioned, Z
1
and Z
2
are each, independently of one another, NR, S or O, R is H, CH
3
or a substituted or unsubstituted, linear or branched, saturated or unsaturated alkyl group having from 2 to 12 carbon atoms of a substituted or unsubstituted, saturated or unsaturated cycloalkyl group or a substituted or unsubstituted aryl group having from 3 to 18 carbon atoms, or any linear or branched sequence of two or more of the groups mentioned, B is a covalent bond, CH
2
or a substituted or unsubstituted, linear or branched, saturated or unsaturated alkylene group having from 2 to 12 carbon atoms or a substituted or unsubstituted, saturated or unsaturated cycloalkylene group or a substituted or unsubstituted arylene group having from 3 to 18 carbon atoms, or any linear or branched sequence of two or more of the groups mentioned, n is from 1 to 20, m is from 1 to 50 and XY is a reactive radical which is inert toward NCO groups, where the reactive radical splits off one or more protective groups Y under acidic, neutral or basic conditions and the radical X bears E, after Y has been split off, at least two groups which are reactive toward isocyanates.
For the purposes of the present invention, the term “reactive radical” refers to a radical which can be converted by a simple chemical reaction, for example by treatment with an acid or a base,
Bruchmann Bernd
Lutter Heinz-Dieter
Renz Hans
BASF - Aktiengesellschaft
Borrego Fernando A.
Cameron Mary K.
Gorr Rachel
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