Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Cellular products or processes of preparing a cellular...
Reexamination Certificate
2000-07-10
2002-06-11
Cooney, Jr., John M. (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Cellular products or processes of preparing a cellular...
C521S137000, C521S155000, C521S170000, C525S031000, C525S039000, C525S438000, C525S444000, C525S445000
Reexamination Certificate
active
06403667
ABSTRACT:
The present invention relates to a macromer which is suitable as stabiliser precursor in polymer polyols. More specifically, the present invention relates to a process for the preparation of a macromer suitable as stabiliser precursor in polymer polyols, to the macromer obtainable by this process, to a process for the preparation of polymer polyols using this macromer and to the polymer polyols obtainable by this process.
Within the context of the present invention a macromer is a compound of which the molecule at least comprises one or more polymerizable double bonds and one or more polyol tails. The double bond can copolymerize with ethylenically unsaturated monomers, thus becoming part of the polymer chain. The polyol tails extending from the polymer chain are compatible with the liquid polyol medium in which the polymer is dispersed, thus stabilising the dispersion. The concept of using macromers as dispersion stabiliser precursors in polymer polyol systems is known as becomes, for instance, apparent from U.S. Pat. Nos. 4,390,645; 5,364,906 and EP-A-0,461,800.
Polymer polyols are commonly used for the manufacture of flexible polyurethane foams. Flexible polyurethane foams are widely used in numerous applications. Main sectors of application are automotive and aircraft industry, upholstered furniture and technical articles. For instance, full foam seats, top pads for the seats and restraints for back and head, all made from flexible polyurethane foam, are widely used in cars and aeroplanes. Other applications include the use of flexible polyurethane foam as carpet backings, bedding and mattresses, foamed seat saddles for motorbikes, gaskets between a car body and its lights, lip seals of air filters for engines and insulating layer on car parts and engine parts to reduce sound and vibration. It will be appreciated that each specific application puts its own demands on the flexible foam to be used. Important characteristics in this connection are density, hardness, resilience and dampening behaviour of the foam and in order to fit each application, these characteristics should be optimally balanced and adjusted.
A problem generally encountered in the manufacture of polymer polyols, i.e. a system wherein a polymer is stably dispersed in a base polyol, is to obtain a polymer polyol having both a relatively high solid polymer content and a sufficiently low viscosity for ease of handling. A polymer polyol having this combination of properties is favourable for the properties of any polyurethane foam produced from such polymer polyol. In order to enable a stable dispersion of the polymer particles in the liquid polyol medium a dispersion stabiliser precursor is generally required.
JP-A-02/247208 discloses a high molecular weight polyether ester polyol as a dispersion stabiliser for a polymer polyol. This dispersion stabiliser is obtained by polymerization of an allyl group-containing polyether ester polyol, which in return is obtained by reacting a polyether polyol with an allyl glycidyl ether, a saturated dicarboxylic acid anhydride and an alkylene oxide in a single step. The polymer polyol is subsequently obtained by dissolving the dispersion stabiliser in a polyether polyol and polymerizing the ethylenically unsaturated monomer(s) therein using a radical polymerization initiator.
Although the dispersion stabiliser disclosed in JP-A-02/247208 results in polymer polyols having relatively high polymer contents (around 45% by weight in the working examples) in combination with relatively low viscosities (around 5000-5500 mPa.s in the working examples), there is still room for improvement, perhaps not so much in terms of the final performance of the dispersion stabiliser, but more in the effectiveness of applying the stabiliser. In this connection the number of process steps to arrive at the stabilised polymer polyol system, the number of components necessary to prepare the stabiliser including neutralizing agents and polymerization catalysts, the processability and ease of handling of the stabiliser and the way in which the stabiliser is prepared are of importance. The present invention aims to optimise all these aspects. Furthermore, the final stabiliser should have an excellent stabilising performance enabling the formation of polymer polyols having a high polymer content in combination with a low viscosity. If such stabilizer could be obtained, this would be attractive from both technical and commercial perspective.
The present invention provides a process for preparing a macromer suitable as a dispersion stabiliser precursor for polymer polyols and having an excellent stabilising performance.
Thus, the present invention relates to a process for the preparation of a macromer suitable as a stabiliser precursor in a polymer polyol, which process comprises reacting a polyol with a cyclic dicarboxylic acid anhydride not containing any polymerizable double bond, and subsequently reacting the adduct thus obtained with an epoxide compound containing a polymerisable double bond.
A main advantage of the process according to the present invention is that it does not involve a separate polymerization step to obtain an isolated stabiliser. Instead, a stabiliser precursor (i.e. the macromer) is obtained. The actual stabiliser is formed during the formation of the dispersed polymer when the macromer reacts with the monomers building this polymer. A further advantage, accordingly, is the fact that in the preparation of the macromer no separate polymerization catalyst or neutralizing agent is necessary. Moreover, the macromer obtained according to the present process is far less viscous than the polymeric stabiliser obtained according to JP-A-02/247208, as a result of which it is easier to handle and has a better processability, i.e. it can be easier blended into the polymerization reaction system.
In GB-A-1,217,005 a process for the preparation of a polyol polymer is disclosed, wherein a polyether polyol is first reacted with a polycarboxylic acid cyclic anhydride whereafter the intermediate product thus obtained is reacted with an 1,2-epoxide, such as ethylene oxide and propylene oxide. Epoxides containing ethylenic unsaturation to enable inclusion in the polymer chain of a polymer derived from ethylenically unsaturated monomers are not disclosed. GB-A-1,217,005 is also silent on polymer polyol systems.
In GB-A-1,126,025 a process for manufacturing modified polymeric polyol is disclosed, wherein an ethylenically unsaturated compound is polymerised under substantially anhydrous conditions in the presence of a free radical polymerization catalyst and a polymeric polyol containing at least 0.7 ethylenically unsaturated groups in the molecule. The polymeric polyol suitably is obtained by reacting a hydroxylated polymer with an unsaturated epoxide such as allyl glycidyl ether. GB-A-1,126,025 is, however, silent on the use of cyclic anhydrides of dicarboxylic acids and on the use of the modified polymeric polyols in polymer polyol systems.
The polyol used for preparing the macromer in the process according the present invention suitably is a polyether polyol, also frequently referred to as polyoxyalkylene polyols. Such polyether polyols are typically obtained by reacting a starting compound having a plurality of active hydrogen atoms with one or more alkylene oxides, such as ethylene oxide, propylene oxide, butylene oxide or mixtures of two or more of these. Suitable polyether polyols are those having a nominal molecular weight in the range of from 2500 to 15,000 and an average nominal functionality (Fn) of at least 2.0. Preferably, the polyol also has a high primary hydroxyl content, suitably of at least 70%. It has been found particularly advantageous to use polyols having a molecular weight in the range of from 5000 to 14,000, a Fn in the range of from 2.5 to 6.0, and a primary hydroxyl content in the range of from 70 to 100%, more preferably from 75 to 95%. The hydroxyl-value of the polyol suitably has a value of from 20 to 150 mg KOH/g, more suitably of from 25 to 75 mg KOH/g.
The dicarboxyl
Eleveld Michiel Barend
Karzijn Willem
Van Kempen Ronald
Cooney Jr. John M.
Shell Oil Company
Tsang Y. Grace
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