Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Mixing of two or more solid polymers; mixing of solid...
Patent
1998-12-17
2000-09-05
Lipman, Bernard
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Mixing of two or more solid polymers; mixing of solid...
525105, 525106, 5253328, 5253324, 5253331, 5253332, 5253337, C08F 800
Patent
active
061144452
DESCRIPTION:
BRIEF SUMMARY
FIELD OF INVENTION
The present invention relates to the hydrosilylation of polypropylene and other polymers, particularly terminal double bonds provided therein.
BACKGROUND TO THE INVENTION
The hydrosilylation reaction, namely the addition of a silicon hydride to a multiple bond, such as carbon-carbon, carbon-nitrogen, nitrogen-nitrogen, carbon-oxygen and nitrogen-oxygen, was first reported in 1947 by Sommer, Pietrusza and Whitmore (ref. 1--the identification of the references appears at the end of the specification). Since then the reaction has been intensively studied and is currently the subject of 44 reviews. Hydrosilylation can be catalysed radically, ionically or with a metal complex, such as platinum, rhodium, palladium. One of the advantages of the platinum-catalysed hydrosilylation is the tolerance of the reaction concerning the presence of functional groups. Oxiranes, acetals, esters, nitriles, amines, amides, nitro, ketone, carbamate, ether, isocyanate, phosphate, phosphonic dichloride, dialkoxy borane, sulfide, sulfone or carborane groups can be present without reacting (ref. 2). Many of these functional groups are of considerable interest in polymer science and it is, therefore, no coincidence that the application of hydrosilylation to functionalise polymers was soon investigated (refs. 3, 4). However, these reactions have almost exclusively been investigated in solution. Although this offers certain advantages, such as good temperature control, mild reaction conditions, and good diffusion (homogenization), it is an energy and labour consuming process. The polymers have to be dissolved, precipitated after the reaction, and subsequently dried. The solvents have to be disposed of or they have to be recycled by distillation. Especially with polymers displaying a low solubility, this is a serious process limitation.
A patentability search conducted by the inventors as disclosed U.S. Pat. Nos. 4,803,244, 5,409,995 and 5,359,113 as potential prior art.
SUMMARY OF THE INVENTION
In accordance with the present invention, there is provided a method of functionalising a polymer in the melt phase by effecting hydrosilylation to terminal double bonds in a polymer to provide a terminal silane on the polymer.
The method of the present invention may be carried out through reactive extrusion, a method that has drawn more and more attention from the scientific community all over the world in recent years. The advantages of performing a reaction in an extruder are that the polymer may be functionalised and processed in the same step. An intermittent solidifying and remelting operation is not necessary. This single step operation saves time, labour, energy, and equipment costs.
Polypropylene is a major commodity polymer used in industry. The low price, good thermal and mechanical properties, chemical inertness, crystallinity and hydrophobic character of polypropylene are desired in many applications. On the other hand, these features restrict its use in other highly profitable areas which are currently dominated by engineering plastics.
Accordingly, the present invention provides a way to chemically alter polypropylene and other polymers to increase features, such as adhesion, chemical reactivity or hydrophilicity. This procedure further opens a path to the formation of interesting copolymers, the production of compatibilizers for inorganic fillers, or polymer blends.
BRIEF DESCRIPTION OF DRAWINGS
FIG. 1 shows a radically induced hydrosilylation reaction. The mechanism comprises the decay of the peroxide, the formation of a silyl radical, attack of the silyl radical on the double bond, and subsequent formation of a saturated organosilane and a new silyl radical.
FIG. 2 shows a hydrosilylation reaction according to the mechanism of Lewis (refs. 8 and 9). The steps include the formation of the colloid, Si--H bond coordination to the surface of the oxygen stabilized platinum and finally, a nucleophilic attack of the olefin on the Si--H bond forming the new silicon product.
FIG. 3 shows the .sup.1 H NMR of
REFERENCES:
patent: 3715334 (1973-02-01), Karstedt
patent: 4803244 (1989-02-01), Umpleby
patent: 5359113 (1994-10-01), Bank
Sommer, L. H., Pietrusza, E. W. & Whitmore, F. C., J Am. Chem. Soc. 69:188 (1947).
Ojima, I. In The chemistry of Organic Silicon Compounds (eds Patai, S. & Rappoport, Z.) 1479-1527 (John Wiley and Sons Ltd. New York, Toronto, 1989).
Mc Grath, M. P., Sall, E. D. & Tremont, S. J. Chem. Rev. 95: 381-398 (1995).
Marciniec, B. Gulinski, J. Urbaniac, W. & Kometka, Z. W., Comprehensive Handbook On Hydrosilylation (Pergamon Press, Oxford, New York, Seoul, Tokyo, 1992).
Dorn M., Advances in Polymer Technology 5, 87-97 (1995).
Tzoganakis, C., Peroxide Degradation Of Polypropylene During Reactive Extrusion. (1988). McMaster University. Ph.D.
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Lewis, L. N., J Am. Chem. Soc. 112: 5998-6004 (1990).
Taylor, R. B., Parbhoo, B. & Fillmore, D. M. in The Analytical Chemistry of Silicones (ed Smith, A.L.) 347-419 (John Wiley and Sons, New York, Toronto, 1991).
Goldstein, G. I. Scanning Electron Microscopy and X-Ray Micro-Analysis (Plenum Press, New York, London, 1981).
Atochem, Evaluation of Organic Peroxides From Half-Life Data. (1992).
Hinsken, H., Moss, S., Pauquet, J. & Zweifel, H. Polymer Degradation and Stability 34: 279-293 (1991).
Box, G. E. P. Hunter, W. G. & Hunter, S. J. Statistics For Experimenters (John Wiley & Sons Inc. New York, Toronto, 1995).
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Hazziza-Lasker, J. Helary, G. & Sauvet, G., Makromol. Chem. Macromol. Symp. 47: 383-391 (1991).
Malz Hauke
Tzoganakis Costas
Lipman Bernard
University of Waterloo
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