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
2002-04-10
2004-06-22
Sergent, Rabon (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...
C252S182270, C252S182280, C252S182290, C528S080000, C560S190000, C560S198000, C560S200000, C568S580000, C568S581000, C568S591000, C568S601000, C568S620000, C568S624000, C568S625000
Reexamination Certificate
active
06753402
ABSTRACT:
The present invention relates to hydroxyl-containing polyether-polyester block copolymers, their preparation and their use, in particular for producing polyurethanes.
Polyurethanes are produced in large quantities. They are usually produced by reacting polyisocyanates with compounds containing at least two hydrogen atoms which are reactive toward isocyanate groups, in particular polyether alcohols and/or polyester alcohols. For various applications, it would be advantageous to build both ether groups and ester groups into the polyurethane. However, owing to the incompatibility of polyether alcohols and polyester alcohols with one another, it is not readily possible to use these two compounds together in polyurethane formulations. One possible way of remedying this disadvantage would be to use polyols which have both groups in the molecule. EP-A-671 424 describes a process for preparing polyols containing ether and ester groups by reacting polyether alcohols with polyfunctional carboxylic acids. However, this process has the disadvantages that the viscosity rises greatly even during the preparation and the products formed have a high viscosity and high molecular weight.
At present, the customary preparation of polyether alcohols by base-catalyzed or acid-catalyzed alkylene oxide addition can only be carried out using initiator substances which are stable toward the base used, generally potassium hydroxide or Lewis acids. Customary initiator substances are, for example, glycerol, sugar and glycol. Due to their ester bond which is unstable toward aqueous bases and acids, polyesterols cannot be used as initiator substances.
The base- or acid-catalyzed alkylene oxide addition onto polyester alcohols would lead to cleavage of the polyesterol chain and to saponification of the polyester polyol right back to its starting components, i.e. the desired block structure could not be obtained in the subsequent alkylene oxide addition. The polyester-polyether polyol cleavage products formed in this way are difficult to reproduce and do not have a defined block structure.
It is an object of the present invention to provide polyols which have both ether groups and ester groups in the molecule, can be prepared by simple methods and do not have the disadvantages of the reaction products of polyether alcohols with polyfunctional carboxylic acids.
We have found that this object is achieved by use of multimetal cyanide compounds, frequently referred to as DMC catalysts, for the polymerization of alkylene oxides using polyesterols as initiator substances. Cleavage of the ester groups in the polyesterols does not occur under these conditions.
The present invention accordingly provides polyester-polyether block copolymers which can be prepared by catalytic addition of alkylene oxides onto H-functional initiator substances, wherein polyester alcohols are used as H-functional initiator substances and multimetal cyanide compounds are used as catalysts. The products obtained in this way preferably contain hydroxyl groups.
The invention further provides a process for preparing polyester-polyether block copolymers and provides for their use for producing polyurethanes by reaction with polyisocyanates.
Surprisingly, the defined preparation of the polyester-polyether block copolymers of the present invention by addition of alkylene oxides onto polyester alcohols using multimetal cyanide catalysts occurs successfully without redissociation of the polyester alcohols and other secondary reactions. The polyester-polyether block copolymers of the present invention have a narrow molecular weight distribution and a low content of unsaturated constituents.
The polyester alcohols used as starting materials for preparing the polyester-polyether block copolymers can be prepared by methods customary for this purpose.
The polyester alcohols used as starting materials for the preparation of the polyester-polyether block copolymers of the present invention are usually prepared by polycondensation of at least bifunctional carboxylic acids with at least difunctional alcohols. The polyesterols can also be prepared by polycondensation or polyaddition reactions of aliphatic, cycloaliphatic, araliphatic and/or aromatic carboxylic acid derivatives with aliphatic, cycloaliphatic, araliphatic and/or aromatic alcohols.
As carboxylic acid derivatives, preference is given to using compounds having at least two carboxyl groups, e.g. maleic acid, fumaric acid, malonic acid, adipic acid, glutaric acid, succinic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid, trimesic acid and/or their anhydrides and/or their acid chlorides.
As alcohols, preference is given to using compounds containing at least two hydroxyl groups, e.g. butanediol, neopentyl glycol, pentanediol, hexanediol, trimethylolpropane, pentaerythritol, glycerol, ethylene glycol and its higher homologues such as diethylene glycol and triethylene glycol, propylene glycol and its higher homologues such as dipropylene glycol and tripropylene glycol.
It is likewise possible to react hydroxycarboxylic acids and/or their derivatives such as lactones with themselves and/or with the abovementioned carboxylic acid derivatives and/or alcohols. Examples which may be mentioned are glycolic acid, lactic acid, hydroxypropionic acid, hydroxybutyric acid and hydroxyvaleric acid.
Polyester alcohols which are particularly preferred as initiator substances are those based on adipic acid and/or phthalic anhydride and monoethylene glycol, diethylene glycol and/or triethylene glycol, monopropylene glycol and/or dipropylene glycol and/or tripropylene glycol.
Apart from the acids mentioned, it is likewise possible to use fatty acid derivatives, in particular dimeric fatty acid derivatives as are marketed, for example, by UNICHEMA under the name Pripol®, derivatives based on castor oil and polyhydroxy fatty acids such as, for example, polyhydroxy fatty acid PHF 110 from Harburger Fettchemie. Also suitable are &agr;,&bgr;-unsaturated carboxylic acids, in particular hydroxy-functionalized &agr;,&bgr;-unsaturated carboxylic acids.
Besides direct reaction, esterification or transesterification variants are also known.
If desired, monofunctional alcohols or carboxylic acids can also be used in small amounts in the synthesis.
Furthermore, the carboxylic acids and alcohols may, if desired, bear further functional groups such as alkyl, aryl, amino, sulfonate, thio, phosphonate or acrylate groups.
The reaction of alcohols with free carboxylic acids is preferred for the preparation of the polyesterols. The polycondensation reaction is usually carried out at from 140 to 250° under atmospheric pressure or subatmospheric pressure. If desired, the reactions are catalyzed, preferably using acids, Lewis acids and metal salts, in particular titanium- and/or tin-containing esterification catalysts, for example n-butyl titanate, tin(II) octoate or tin dilaurate. The water of reaction is preferably distilled off until the reaction mixture has an acid number of <10 mg KOH/g, particularly preferably <3 mg KOH/g and in particular <1 mg KOH/g. It is also possible in principle to use polyester alcohols having higher acid numbers, since the excess acid groups react with the alkylene oxides. In a further embodiment, the reaction can be carried out under inert gas such as nitrogen or argon in order to prevent product discoloration due to oxidation products. Depending on the use for which the polyester polyols are intended, they have a hydroxyl number of from 0.5 to 500 mg KOH/g, preferably from 10 to 400 mg KOH/g, and in particular from 30 to 300 mg KOH/g. Thus, the polyester polyols preferably have a number average molecular weight Mn of from 250 to 200,000.
A summary overview of the preparation of polyesterols and their use for producing polyurethanes, in particular polyurethane foams, is given, for example, in the Kunststoff-Handbuch, Volume VII, “Polyurethane” 3
rd
edition 1993, edited by Dr. G. Oertel (Carl-Hanser-Verlag, Munich).
If t
Bauer Stephan
Baum Eva
Dinsch Stefan
Grosch Georg Heinrich
Harre Kathrin
BASF - Aktiengesellschaft
Borrego Fernando A.
Sergent Rabon
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