Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Cellular products or processes of preparing a cellular...
Reexamination Certificate
2000-01-20
2002-10-29
Gorr, Rachel (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Cellular products or processes of preparing a cellular...
C528S075000, C525S131000, C525S404000, C524S762000, C252S182170
Reexamination Certificate
active
06472447
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to finely dispersed, low-viscosity polymer polyols which are stabilized in a novel manner and have a high content of polystyrene or polystyrene copolymers. It also relates to a process for the preparation of these polymer polyols and to their use for the preparation of polyurethanes, and particularly polyurethane foams.
Polymer polyols in the context of the invention are to be understood as products which can be obtained by polymerization of ethylenically unsaturated compounds in polyols, so-called base polyols. Suitable polyols on which the polymer polyols are based are those normally used in polyurethane chemistry, and above all the known polyester and polyether polyols and mixtures thereof. As mentioned above, the polymer polyols can be used for the preparation of polyurethane foams. The polymers of ethylenically unsaturated compounds contained in the polymer polyols, in particular based on styrene or mixtures of styrene and acrylonitrile, are used chiefly for controlled modification of the physical properties of the polyurethane plastics prepared from the polymer polyols.
To prevent the polymers based on ethylenically unsaturated compounds from sedimenting or coagulating in the so-called base polyols, so-called dispersion stabilizers are added to the base polyols. Examples of such dispersion stabilizers are the known macromers or the known prepolymers containing OH end groups. Such dispersion stabilizers are described, for example, in U.S. Pat. Nos. 4,357,430, 4,454,255 and 4,689,354, and in EP 0,768,324.
A disadvantage of using macromers as stabilizers in the preparation of polymer polyols with a high content of polystyrene is that it is very difficult to obtain finely dispersed products which can be filtered. If prepolymers with terminal OH groups are used as stabilizers for such polymer polyols, there is the disadvantage that such polymer polyols have comparatively high viscosities.
An improved stabilizer system for polystyrene-rich polymer polyols is described, for example, in EP 0,495,551 and EP 0,786,480, in which polyether polyols linked via polyfunctional isocyanates are employed as stabilizers. However, when the stabilizers of in EP 0,495,551 and EP 0,786,480 are employed, these also do not result in satisfactory viscosities for polymer polyols with a high solids content.
The object of the present invention is to provide improved finely dispersed, low-viscosity polymer polyols which are easy to filter and have a high content of styrene or styrene copolymers, while avoiding the disadvantages with respect to stabilizing the polystyrene-rich polymer polyols to date.
DESCRIPTION OF THE INVENTION
The present invention therefore provides finely dispersed, low-viscosity polymer polymers which are stabilized in a novel manner. These polymer polyols comprise:
(A) a base polyol;
(B) a polymer comprising (1) styrene, or (2) a mixture of styrene and at least one other ethylenically unsaturated monomer; and
(C) a polymer containing mercaptan and/or disulfide groups which is compatible with base polyol component (A), has an average molecular weight of 500 to 100,000, an average of at least 0.5 mercaptan groups or 1 disulfide group per molecule and a viscosity in the range of 100 to 80,000 mPa.s (measured at a temperature of 25° C., according to DIN 53019/shear rate: 48/s),
wherein component (B) is present in an amount of 30 to 60% by weight and component (C) is present in an amount of 1 to 6% by weight, with the %'s by weight of (B) and (C) being based on the combined weight of components (A), (B) and (C) in the finished polymer polyol.
In the polymer polyols according to the present invention, it is preferred that component (B) is present in an amount of 35 to 55% by weight, and that component (C) is present in an amount of 2 to 4% by weight, with the %'s by weight of (B) and (C) being based on the combined weight of components (A), (B) and (C) in the finished polymer polyol.
Suitable polyols to be used as the base polyol component (A) of the present invention include all polyols which are known and conventionally employed in the preparation of polyurethanes. These include the known polyether polyols and polyester polyols, which can be employed both individually and in any desired mixtures with one another. Polyurethanes containing several hydroxyl end groups, phosphorus compounds containing several hydroxyl groups, and other compounds containing several hydroxyl groups, such as are described in detail in, for example, U.S. Pat. No. 4,454,255, are also suitable to be used as base polyols in the present invention.
It is preferred that polyether polyols and/or polyester polyols are employed as the base polyol, and most preferably polyether polyols are employed.
Suitable polyether polyols to be employed as the base polyol of the present invention include, preferably, those which are obtained by an addition reaction of a suitable starter compound containing at least two active hydrogen atoms on cyclic ethers. Examples of such polyether polyols are those which are obtained by reaction of an alkylene oxide such as, for example, ethylene oxide, propylene oxide, butylene oxide, tetrahydrofuran and mixtures thereof, with one or more polyfunctional starter compounds, such as alkylene glycols, e.g. glycerol, trimethylolpropane, pentaerythritol, sorbitol, glucose and sucrose. Other suitable starter compounds include, for example, water, ammonia, amino alcohols such as, for example, ethanolamine, diethanolamine and triethanolamine, and primary and/or secondary amines or polyamines, such as, for example, ethylenediamine, aniline and toluenediamine. The polyether polyols to be employed as base polyols according to the invention usually have a molecular weight of 500 to 12,000, preferably 2,000 to 8,000, and have a hydroxyl functionality of 2 to 6. Polyether polyols which are more preferably employed are those which are obtained by reaction of ethylene oxide and/or propylene oxide with the above mentioned starter compounds containing several hydroxyl groups.
Suitable polyester polyols which are used in the mixtures according to the invention are, in particular, those which are derived from polycarboxylic acids and polyalcohols. Polycarboxylic acids which are suitable for the preparation of polyester polyols include compounds such as, for example, oxalic acid, malonic acid, glutaric acid, adipic acid, maleic acid, fumaric acid, isophthalic acid and/or terephthalic acid. Suitable polyalcohols include both aliphatic polyalcohols and aromatic polyalcohols such as, for example, ethylene glycol, propylene glycol, trimethylene glycol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,2-pentanediol, 1,4-pentanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, glycerol, 1,1,1 -trimethylolpropane, 1,1,1 -trimethylolethane, 1,2,6-hexanetriol, &agr;-methylglycositol, pentaerythritol and/or sorbitol, and polyether polyols with a molecular weight of 500 to 6,000 and a hydroxyl functionality of 2 to 8. Polyalcohols which are derived from phenol, such as bisphenol A, can furthermore be employed. Polyester polyols which can also be employed are those which are derived from corresponding polyester-amides (reaction products of corresponding amines or amino alcohols with polycarboxylic acids, such as are described in, for example, U.S. Pat. No. 4,454,255). Polycarbonates containing hydroxyl groups are also suitable.
The reaction products from the above mentioned polycarboxylic acids with the polyether polyols and/or the low molecular weight polyols in a suitable ratio of amounts are preferably employed as polyester polyols.
The polyester polyols to be employed as based polyols in the present invention have an average molecular weight which substantially corresponds to the average molecular weight of the above mentioned polyether polyols. This also applies to the hydroxyl functionality.
Those polymers which are built up from (1) styrene, or (2) a mixture of styrene and at least one other ethylenically unsaturated monomer are used as compon
Brockelt Michael
Dietrich Manfred
Grönen Jürgen
Jacobs Gundolf
Kumpf Robert-Joseph
Brown Denise
Gil Joseph C.
Gorr Rachel
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