Copolymers of isocyanato silicones

Abstract: A novel isocyanato-endcapped siloxane compound and a method of preparation are disclosed, and which can be further copolymerized with a variety of thermoplastic resins containing active hydrogen substituents such as polycarbonates and polyphenylene ethers.

Description: The present invention relates to novel modified silicone fluids. More particularly, the present invention relates to novel silicone fluids modified with alkenyl isocyanato groups. The present invention further relates to copolymers or polymers containing active hydrogen substituents and the alkenyl isocyanato modified silicones. BACKGROUND OF THE PRESENT INVENTION Copolymers of polysiloxanes and other thermoplastic resins have found wide utility in commercial applications. For example, it is known in the art that polycarbonates can be copolymerized with linear polysiloxanes which are modified with allyl phenolic endgroups. These organopolysiloxane polycarbonate copolymers are disclosed in Vaughn, Jr., United States Patent Nos. 3,419,634 and 3,419,635. Due to the usefulness of such copolymers, new methods for preparing siloxane copolymers are continuously sought after. Zhou et al., Polymer Bulletin 22, 85-88 (1989) describe the hydrosilation of an alkenyl isocyanate onto cyclic siloxanes containing SiH groups, such as 1,3,5,7-tetramethylcyclotetrasiloxane. However, long reaction times are necessary and poor yields are obtained. Journal of Polymer Science Part A; Polymer chemistry Edition 29(1991)July, No. 8. New York, USA, and US-A-5157095 disclose polyfunctional aliphatic isocyanates obtained by the hydrosilylation of m-isopropenyl-α,α-dimethylbenzyl isocyanate (m-TM1) with cyclic and acyclic hydrogenmethylsiloxanes. The products were characterized by 1 H- and 13 C-NMR, IR and GPC, and all result exclusively from β-addition to m-TMI. Polymers with SiH groups are also effective hydrosilylating agents of m-TMI. The isocyanato siloxanes can be used as precursors for star and network polymers as well as other polyfunctional reagents. EP-A-0077744 discloses organopolysiloxane/ polyurethane block copolymers wherein the polyurethane block is derived from an unsaturated isocyanate such as 3-(p-isocyanato phenoxy)propene. It has now been discovered that novel siloxanes which are endcapped with isocyanate functionalities can be easily prepared and are useful in producing siloxane copolymers with thermoplastics containing alcohol and/or amine substituents. Further, the copolymerization produces no reaction by-products. SUMMARY OF THE PRESENT INVENTION According to the present invention there is provided a siloxane polymer comprising units of the formulae: M'M; M'M'; M'D x M; and M'D x M' wherein M represents a monofunctional siloxane of the formula R 3 SiO 1/2 ; M' represents a monofunctional siloxane of the formula R' a R b SiO 1/2 ; D represents a difunctional siloxane of the formula R 2 SiO 2/2 ; each R is the same or different and independently represents a substituted or unsubstituted monovalent hydrocarbon of from 1 to 30 carbon atoms; each R' is the same or different and independently represents a residue of 1-(1-isocyanato-1-methylethyl)3-(1-methylethenyl)benzene an alkenyl isocyanato radical; "a" is an integer of 1, 2 or 3; "b" is an integer of 0, 1 or 2; a+b= 3; and "x" is an integer of above 1. Also according to the present invention, there is provided a process for producing the siloxane polymer of the present invention comprising reacting the corresponding monofunctional hydride siloxane in the presence of a hydrosilation catalyst with 1-(1-isocyanato-1-methylethyl)-3-(1-methylethenyl)-benzene. The present invention further provides copolymers of the siloxanes of the present invention with thermoplastic resins containing alcohol and/or amine substituents. DETAILED DESCRIPTION OF THE PRESENT INVENTION The present invention provides novel isocyanato endcapped siloxane polymers which are useful as reactive polymers and may be employed in preparing siloxane copolymers with thermoplastic resins having active hydrogen substituents to provide improved impact properties and reduced smoke density upon burning. Particularly useful isocyanato-endcapped siloxanes of the present invention are those generally comprising units of the formulae: M'M; M'D x M; and M'D x M' In the above formula M represents a monofunctional siloxane of the formula R 3 SiO 1/2 ; M' represents a monofunctional siloxane of the formula R' a R b SiO 1/2 ; and D represents a difunctional siloxane of the formula R 2 SiO 2/2 . Each R is the same or different and independently represents a substituted or unsubstituted monovalent hydrocarbon of from 1 to 30 carbon atoms. Illustratively, R typically contains no more than eight carbon atoms, and is selected from, but not limited to, those such as substituted or unsubstituted alkyl radicals, e.g., methyl, ethyl and isopropyl; cycloaliphatic radicals, e.g., cyclopentyl and cyclohexenyl; alkenyl radicals, e.g., vinyl and allyl; aryl radicals, e.g., benzyl and phenyl; alkaryl and aralkyl groups. In preferred embodiments of the present invention, all of the R groups represent a methyl group. Each R' is a residue of 1-(1-isocyanato-1-methylethyl)-3-(1-methylethenyl)-benzene. "a" is an integer of 1, 2 or 3; "b" is an integer of 0, 1 or 2; provided a+b= 3. "x" is an integer of above 1, and typically ranges from 1 to 1000, more preferably from 1 to 100, and most preferably from 1 to 20. Particularly useful compositions of the present invention comprise those of the formulae: and wherein R' is a residue of 1-(1-isocyanato-1-methylethyl)-3-(1-methylethenyl)-benzene. The novel isocyanato silicones of the present invention are generally prepared by hydrosilylating the appropriate linear or branched siloxane with the above alkenyl isocyanate. The silicone hydrides for use in the practice of the present invention are typically those which correspond to the product isocyanato siloxanes, and are generally selected from M H M, M H D x M, M H D x M H or combinations of any of the foregoing wherein M H is a monofunctional siloxane hydride of the formula (R) 2 (H)SiO 1/2 and R, D, M and x are as above defined. The monofunctional siloxane hydrides are available commercially and can be prepared by methods known to those skilled in the art. 1-(1-isocyanato-1-methylethyl)-3-(1-methylethenyl)-benzene has the formula: This compound is described in the literature and is commercially available as TMI® from American Cyanamid Company. See, inter alia , Dexter et al., "m-TMI, A Novel Unsaturated Aliphatic Isocyanate," Journal of Coatings Technology, v. 5, n. 737, pp. 43-47 (June 1986); and TMI® (META) unsaturated aliphatic isocyanate brochure, American Cyanamid Company. The monofunctional siloxane hydride and the alkenyl isocyanate compound are typically mixed in the presence of an inert solvent prior to reaction. Particularly useful as a solvent are the normally liquid aliphatic, cycloaliphatic or aromatic hydrocarbon or halogenated hydrocarbon compounds of from 6 to 15 carbon atoms. These include, but are not limited to, n-heptane, cycloheptane, n-hexane, cyclohexane, benzene, toluene, xylene, styrene, mesitylene, naphthene, methylene chloride and mixtures thereof. The hydrocarbon solvent may also comprise polyalpha-olefins and mineral oils such as mineral spirits. The monofunctional siloxane hydride and the alkenyl isocyanate are then generally reacted by hydrosilation techniques well known to those of ordinary skill in the art. In general the hydrosilation reaction proceeds in the presence of a Group VIII precious metal complex, i.e. platinum, rhodium and/or ruthenium complexes. Such catalyst complexes are well described in the patent literature, e.g., Karstedt, United States Patent No. 3,775,452; Ashby et al., United States Patent No. 4,288,345; Bailey et al., United States Patent No. 3,336,239; Ashby, United States Patent No. 4,421,903; Lamoreaux, United States Patent No. 3,220,972; and Lewis, United States Patent No. 4,946,818. See also, J. Organometallic Chem. 408 (1991) pp. 297-304. Preferred are the platinum based catalysts described in abovementioned Lamoreaux and Karstedt patents. Most preferred are a platinum octanol catalyst, a diplatinum tris(divinyl tetramethylsiloxane) catalysts may include complexes of tertiary amines with catalyst and an amine cuprous chloride complex. The reaction proceed at temperatures ranging from 50°C to 150°C and pressures ranging from 1 atm to 5 atm for a period of time of from 1 hour to 5 hours. The ratio of reagents ranges from 1:1, moles isocyanate:moles siloxane hydride, to potentially excess siloxane hydride. The product isocyanato endcapped siloxane is then purified from the inert solvent by standard distillation techniques. The isocyanato siloxane can then be used as a reactive additive or can be copolymerized with copolymerizate thermoplastic resins containing alcohol and/or amine substituents to provide the novel copolymers of the present invention. Useful thermoplastic copolymerizates having alcohol and/or amine substituents are those such as polycarbonates, polyphenylene ethers, polyols and polyamines. Copolymerization occurs between the isocyanate group on the siloxane and the active hydrogen, i.e., hydroxy or amine, present in the copolymerizate, by the formation of a urethane or urea linkage, respectively. The copolymerization is described below with regard to polycarbonate, however, any thermoplastic containing an active alcohol or amine substituent may be employed, such as polyphenylene ethers. The polycarbonates useful in the practice of the present invention are well known to those skilled in the art and can comprise non-aromatic as well as aromatic forms. With respect to aromatic polycarbonates, these can be made by those skilled in this art or they can be obtained from a variety of commercial sources. They may be prepared by reacting a dihydric phenol with a carbonate precursor, such as phosgene, a haloformate or carbonate ester. Typically they will have recurring structural units of the formula: wherein A is a divalent aromatic radical of the dihydric phenol employed in the polymer producing reaction. Preferably, the aromatic carbonate polymers have an intrinsic viscosity ranging from 0.30 to 1.0 dl/g (measured in methylene chloride at 25°C). By dihydric phenols is meant mononuclear or polynuclear aromatic compounds containing two hydroxy radicals, each of which is attached to a carbon atom of an aromatic nucleus. Typically, dihydric phenols include 2,2-bis(4-hydroxyphenyl)propane; 2,2-bis(3,5-dimethyl-4-hydroxyphenyl)propane; 4,4'-di-hydroxydiphenyl ether; bis(2-hydroxyphenyl)methane and mixtures thereof. The preferred aromatic carbonate polymer is a homopolymer derived from 2,2-bis(4-hydroxyphenyl)propane or bisphenol-A. The isocyanate-endcapped siloxane is merely added to the polycarbonate resin, in either a solvent or the liquified resin, and the reaction proceeds by the interaction of the isocyanate with the hydroxy group of the polycarbonate, polyphenylene ether or polyol, or the amine group of the polyamine, as is known to those skilled in the art. See, e.g., J.H. Saunders, Rubber Chem. & Tech., v. XXXIII, n. 5, Dec. 1960, pp. 1293-94. In the case of a solventless system, the reaction would not produce any waste or by-product since all reagents could combine to form the desired product. The resulting copolymers can then be molded into a wide variety of useful commercial products. DESCRIPTION OF THE PREFERRED EMBODIMENTS The following examples are presented for illustrative purposes only. They are not to be construed to limit the scope of the appended claims in any manner whatsoever. COMPARATIVE EXAMPLE A ATTEMPTED HYDROSILYLATION BETWEEN D H 4 AND TMI 10 g (49.8 mmol) of TMI was combined with the platinum-octanol catalyst described by Lamoreaux (United States Patent No. 3,220,972)(35µL of 3.5% Pt by weight solution) in 50 mL mesitylene. Then 3 g (50 mmol/SiH) D H 4 was added and the mixture was refluxed for 13 hours. Analysis by gas chromatography showed no conversion of starting materials occurred. The reaction was repeated by reversing the order of addition of reagents so that D H 4 was combined with platinum catalyst, this time as described by Karstedt, diplatinum tris(divinyl tetramethyl disiloxane (United States Patent No. 3,775,452)(3.5µL of 5% Pt by weight in xylene) in mesitylene, followed by addition of TMI. Again, no trace of product was observed. EXAMPLE 1 Reaction of TMI with M H M H . 10 g (49.6 mmol) of TMI and 6.6 g (49.2 mmol) of M H M H were combined in 50 mL toluene. To the mixture is then added Karstedt platinum catalyst (40µL of a 5% Pt solution in xylene). The mixture was refluxed for 3 days, at which point gas chromatography analysis showed 66% conversion to products had occurred. The product where Me represents methyl, was isolated in about 45% yield by distillation, 0.3 mm, 103-108°C. Analysis by 1 H NMR spectroscopy showed: -0.02 (s 6H), 0.22 (s, 6H), 1.01 (d, J=7Hz, 2H), 1.32 (d, J=7Hz, 3H), 1.74 (s, 6H), 2.98 (m, 1H), 4.70 (m, 1H), 7.2 (m, 4H). EXAMPLE 2 Reaction of TMI with M H M. 10 g (49.6 mmol) of TMI and 10.0 g (56.8 mmol) of M H M were combined in 50 mL toluene. To the mixture is then added Karstedt platinum catalyst (40µL of a 5% Pt solution in xylene). The mixture was refluxed for 13 hours, at which point gas chromatography analysis showed greater than 90% conversion to products had occurred. The product where Me represents methyl was purified by distillation, 0.4 mm, 103-108°C. Analysis by 1 H NMR spectroscopy showed: -0.02 (s 6H), 0.11 (s, 9H), 1.01 (d, J=7Hz, 2H), 1.34 (d, J=7Hz, 3H), 1.76 (s, 6H), 2.98 (m, 1H), 7.2 (m, 4H). Analysis of 13 C NMR spectroscopy showed 0.85 (SiCH 3 ), 2.00 (SiCH 3 ), 26.00 (CH 3 ), 28.54 (CH 2 ), 33.10 (CH 3 ), 35.91 (CH), 60.89 (c, quat), 121.72 (aromatic CH), 122.81 (aromatic CH), 125.46 (aromatic CH), 128.39 (aromatic CH), 150.17 (c, quat). Infra red spectroscopy showed 2262 cm -1 υ co . Other major peaks, 2959 cm -1 , 1256 cm -1 , 1057 cm -1 , 841 cm -1 , 817 cm -1 , 799 cm -1 , 470 cm -1 . High resolution GCMS calculated C 18 H 31 NOSi 2 349.1893. Found 349.1883. Many variations of the present invention will suggest themselves to those skilled in the art in light of the above-detailed description. For example, any siloxane can be employed which is endcapped with the isocyanate compound, such as those of the formulae M'D x M and M'D x M'. The isocyanate functional silicones can then be reacted with hydroxy or amine containing compounds such as polycarbonates, polyphenylene ethers, polyols and polyamines. All such obvious modifications are within the full intended scope of the present invention.

Claims: A siloxane polymer comprising units of the formula: M'M M'D x M M'D x M' wherein M represents a monofunctional siloxane of the formula R 3 SiO 1/2 ; M' represents a monofunctional siloxane of the formula R' a R b SiO 1/2 ; D represents a difunctional siloxane of the formula R 2 SiO 2/2 ; each R is the same or different and independently represents a substituted or unsubstituted monovalent hydrocarbon of from 1 to 30 carbon atoms; each R' is the same or different and independently represents a residue of 1-(1-isocyanato-1-methylethyl)-3-(1-methylethenyl)-benzene; "a" is an integer of 1, 2 or 3; "b" is an integer of 0, 1 or 2; a+b= 3; and x is an integer of above 1. A siloxane polymer as defined in claim 1 wherein each R is the same or different and is selected from alkyl, cycloalkyl, alkenyl, aryl, alkaryl, aralkyl groups A siloxane polymer as defined in claim 1 wherein x ranges from 1 to 1000. A siloxane polymer as defined in claim 1 comprising wherein each R' represents 1-(1-isocyanato-1-methylethyl)-3-(1-methylethenyl)-benzene. A siloxane polymer as defined in claim 1 comprising wherein R' represents 1-(1-isocyanato-1-methylethyl)-3-(1-methylethenyl)-benzene. A process for preparing a siloxane polymer comprising units of the formula; M'M M'D x M M'D x M' wherein M represents a monofunctional siloxane of the formula R 3 SiO 1/2 ; M' represents a monofunctional siloxane of the formula R' a R b SiO 1/2 ; D represents a difunctional siloxane of the formula R 2 SiO 2/2 ; each R is the same or different and independently represents a substituted or unsubstituted monovalent hydrocarbon of from 1 to 30 carbon atoms: each R' is a residue of 1-(1-isocyanato-1-methylethyl)-3-(1-methylethenyl)-benzene; "a" is an integer of 1, 2 or 3; "b" is an integer of 0, 1 or 2; a+b= 3; and x is an integer of above 1; said process comprising: mixing the corresponding monofunctional hydride siloxane of the formulae: M H M M H D x M M H D x M H with 1-(1-isocyanato-1-methylethyl)-3-(1-methylethenyl)benzene; and reacting said monofunctional hydride siloxane and 1-(1-isocyanato-1-methylethyl)-3-(1-methylethenyl)-benzene in the presence of a hydrosilation catalyst. A process as defined in claim 6 wherein said mixing step is conducted in the presence of a solvent selected from normally aliphatic, cycloaliphatic or aromatic hydrocarbon or halogenated hydrocarbon compounds of from 6 to 15 carbon atoms. A process as defined in claim 6 wherein said catalyst comprises a platinum octanol catalyst, a diplatinum tris(divinyl tetramethyl siloxane) catalyst or an amine cuprous chloride complex. A siloxane copolymer comprising units derived from an isocyanate endcapped siloxane polymer comprising units of the formula: M'M M'D x M M'D x M' wherein M represents a monofunctional siloxane of the formula R 3 SiO 1/2 ; M' represents a monofunctional siloxane of the formula R' a R b SiO 1/2 ; D represents a difunctional siloxane of the formula R 2 SiO 2/2 ; each R is the same or different and independently represents a substituted or unsubstituted monovalent hydrocarbon of from 1 to 30 carbon atoms; each R' is the same or different and independently represents a residue of 1-(1-isocyanato-1-methylethyl)-3-(1-methylethenyl)-benzene; "a" is an integer of 1, 2 or 3; "b" is an integer of 0, 1 or 2; a+b= 3; and x is an integer of above 1; and a copolymerizate having alcohol and/or amine substituents.

Inventors: LEWIS LARRY NEIL, LUCARELLI MICHAEL ANTHONY, RALEIGH WILLIAM JOHN, LEWIS, LARRY NEIL, LUCARELLI, MICHAEL ANTHONY, RALEIGH, WILLIAM JOHN
Applicants: GEN ELECTRIC, GENERAL ELECTRIC COMPANY
Application year: 1993
Main classification: C08G77
IPC codes: C08G77, C07F7