Organopolysiloxane modified polyesters and method for the preparation thereof

Abstract: The present invention relates to a novel organopolysiloxane-modified polyester and a preparatory method for the same. The oganopolysiloxane-modified polyester polymer comprises a polyester segment having a number average molecular weight of 300 to 15,000, a silicon-bonded hydrolyzable group-free organopolysiloxane segment, and a silicon-bonded hydrolyzable group-containing silicone segment. The compositions of the present invention are curable at room temperature in the presence of a condensation-reaction catalyst.

Description: The present invention provides an organopolysiloxane-modified polyester containing both silicon-bonded hydrolyzable group-free organopolysiloxanes and silicon-bonded hydrolyzable group-containing silicon compounds. The invention also relates to a method for the preparation of organopolysiloxane-modified polyesters. The modification of polyesters with organopolysiloxanes is an effective tatic for improving such properties as releaseability, water repellency, weather resistance, and slip. Interest has most recently focused on organopolysiloxane-grafted polyesters as disclosed in Japanese Patent Publications [Kokai] 3-74459 [74,459/1991] and 3-2221 [2,221/1991]. However, the polyester materials described above are noncrosslinking. As a result, when they are used for coatings, the product film is fragile and redissolves when brought into contact with a solvent. A need therefore exists for an organopolysiloxane-grafted polyester resin that is capable of crosslinking at room temperature. The organopolysiloxane-modified polyester of this invention comprises a polyester having a number average molecular weight of 300 to 15,000 which contains silicon-bonded hydrolyzable group-free organopolysiloxane groups and silicon-bonded hydrolyzable group-containing silicon compounds. It also introduced an organopolysiloxane-grafted polyester that is capable of crosslinking at room temperature, and producing compositions which can cure at room temperature in the presence of a condensation-reaction catalyst. The present invention relates to organopolysiloxane-modified polyester graft copolymer comprising: (a) a polyester segment having a number average molecular weight of 300 to 15,000, (b) an organopolysiloxane segment, and (c) a silicon segment having at least one silicon-bonded hydrolyzable group in the segment, with the proviso that the organopolysiloxane segment (b) does not contain silicon-bonded hydrolyzable groups. The main chain of the organopolysiloxane-modified polyester of the present invention comprises polyester, the polyester having a silicon-bonded hydrolyzable group-free (SBHG-free) organopolysiloxane segment and a silicon-bonded hydrolyzable group-containing (SBHG-containing) silicon segment. Both segments are preferably bonded in a side chain position on the polyester main chain. The number average molecular weight of the polyester main chain is 300 to 15,000. This polyester may be aliphatic polyester or aromatic polyester and may be linear or branched. The polyester segment (a) comprises from 10 to 79 weight percent of the copolymer. The organopolysiloxane segment (b) may be bonded to the carboxylic acid moiety or alcohol moiety of the polyester; it may be bonded directly to carbon atom in the carboxylic acid or alcohol moiety; or it may be bonded thereto across oxygen. The terminal groups of the polyester are preferably ester groups or hydroxyl groups. The SBHG-free organopolysiloxane graft segment (b) of the polymer is preferably straight chain but can also be branched. Its degree of polymerization is at least 2 but is not otherwise specifically restricted. However, at excessively large degrees of polymerization, acquisition becomes problematic and the corresponding precursor organopolysiloxane has a poor addition reactivity. For this reason, the degree of polymerization generally does not exceed 2,000 and is preferably 3 to 100 on average. The SBHG-free organopolysiloxanes of segment (b) are exemplified by trimethylsiloxy-terminated dimethylpolysiloxanes, trimethylsiloxy-terminated methylalkyl (C 2 - C 10 ) polysiloxanes, and trimethylsiloxy-terminated methylphenylpolysiloxanes. The organopolysiloxane segment (b) of the copolymer preferably comprises from 20 to 75 weight percent of the copolymer. The SBHG-containing silicon compound graft segment (c) of the polymer of this invention contains no specific restrictions with respect to its molecular structure other than the requirement of containing a silicon-bonded hydrolyzable group. The silicon-bonded hydrolyzable group of segment (c) is exemplified by alkoxy groups such as methoxy, ethoxy, propoxy, and by acetoxy groups or groups such as methyl ethyl ketoxime. The silicon segment (c) of this invention is exemplified by polysiloxanes such as trimethoxysiloxy-terminated dimethylpolysiloxanes and trimethoxysilylethyl-terminated dimethylpolysiloxanes. The silicon segment (c) preferably comprises from 1 to 15 weight percent of the copolymer of the instant invention. The present invention further relates to an organopolysiloxane-modified polyester composition comprising a reaction product of: (a) an aliphatically unsaturated polyester having a number average molecular weight of 300 to 15,000, (b) an organopolysiloxane having at least one silicon-bonded hydrogen atom in its molecule, (c) a silicon compound having in its molecule at least one silicon-bonded hydrogen atom and at least one silicon-bonded hydrolyzable group, and (d) a hydrosilylation-reaction catalyst, wherein said reaction takes place in the presence of (d) and with the proviso that (b) is free of silicon-bonded hydrolyzable groups. The present invention also relates to a method for the preparation of an organopolysiloxane-modified polyester comprising reacting: (a) an aliphatically unsaturated polyester having a number average molecular weight of 300 to 15,000, (b) an organopolysiloxane having at least one silicon-bonded hydrogen atom in its molecule, (c) a silicon compound having in its molecule at least une silicon-bonded hydrogen atom and at least one silicon-bonded hydrolyzable group, in the presence of (d) a hydrosilylation-reaction catalyst, with the proviso that (b) is free of silicon-bonded hydrolyzable groups. The polyester comprising the component (a) used in the preparative method and the compositions of the present invention consists of an aliphatically unsaturated polyester with a number average molecular weight of 300 to 15,000. The bases for this molecular weight range are as follows: at below 300, the curing rate is slow; at above 15,000, the solvent solubility is reduced and the processability is therefore poor. Methods for the preparation of component (a) are exemplified by (i) the condensation reaction of a polyvalent carboxylic acid with an aliphatically unsaturated polyhydric alcohol, and (ii) the condensation reaction of polyhydric alcohol with aliphatically unsaturated polyvalent carboxylic acid. The polyvalent carboxylic acid is exemplified by phthalic acid, isophthalic acid, terephthalic acid, tetrahydrophthalic acid, tetrachlorophthalic acid, oxalic acid, malonic acid, succinic acid, adipic acid, sebacic acid, cyclopentanedicarboxylic acid, trimellitic acid, and pyromellitic acid. The aliphatically unsaturated polyvalent carboxylic acids are exemplified by allyloxyisophthalic acid, allyloxyterephthalic acid, and allylmalonic acid. These carboxylic acids may be used singly or in combination. The form of the polyvalent carboxylic acid component, i.e., the carboxylic acid or derivative thereof (for example an alkyl ester or halide) is selected as appropriate to the particular polycondensation method. The polyhydric alcohol is exemplified by ethylene glycol, propylene glycol, butanediol, hexamethylene glycol, hydrogenated bisphenol A, neopentyl glycol, diethylene glycol, triethylene glycol, dipropylene glycol, glycerol, trimethylolpropane, trimethylolethane, and pentaerythritol. The aliphatically unsaturated polyhydric alcohol is exemplified by glycerol monoallyl ether, trimethylolpropane monoallyl ether, trimethylolethane monoallyl ether, pentaerythritol monoallyl ether, and pentaerythritol diallyl ether. These alcohols may be used singly or in combination. The residual carboxylic acid or carbinol functional groups in this component are preferably blocked with a silylating agent such as trimethylmonochlorosilane or hexamethyldisilazane. The organopolysiloxane comprising component (b) used in the invention contains at least one silicon-bonded hydrogen atom in its molecule and is free of silicon-bonded hydrolyzable groups. It may have a straight-chain, branched-chain, or network structure, but straight-chain structures are preferred. Methods for the preparation of this component are known. Its molecular weight is not specifically restricted, but its average degree of polymerization is preferably 3 to 300 and more preferably 5 to 200. The organic groups present in addition to silicon-bonded hydrogen are alkyl groups such as methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, abnd octyl; aryl groups such as phenyl, and naphthyl; and aralkyl groups such as benzyl, or phenethyl. Methyl preferably makes up at least half of the organic groups. The amount of component (b) in this invention is preferably from 25 to as much as 400 weight parts per 100 weight parts of component (a). The silicon compound comprising the component (c) used in the preparative method and compositions of the invention contains at least one silicon-bonded hydrogen and at least one silicon-bonded hydrolyzable group in its molecule. The silicon-bonded hydrolyzable group in this component may be any group that does not inhibit the addition reaction. Molecular weights are preferred for this component that permit purification by distillation. The organic groups present in addition to the silicon-bonded hydrogen and silicon-bonded hydrolyzable group are exemplified by the organic groups listed in the preceding description of component (b). Component (c) is exemplified by organopolysiloxanes with the following chemical structures: and Other examples are trimethoxysilane, methyldimethoxysilane; triacetoxysilane, and tri(methyl ethyl ketoxime)silane. The amount of component (c) in the compositions and method of this invention is preferably from 1 to 50 weight parts per 100 weight parts of component (a). The hydrosilylation-reaction catalyst comprising component (d) in the preparative method of the invention is used in order to effect grafting of components (b) and (c) onto component (a) through a silylation reaction. This catalyst encompasses the complexes of transition metals such as platinum, palladium, rhodium, ruthenium, cobalt, and nickel. Platinum group catalysts such as chloroplatinic acid, platinum/olefin complexes, and chloroplatinic acid/vinylsiloxane complexes, are preferred because they have high catalytic activities and produce few secondary reactions. The amount of component (d) in the compositions and method of this invention is preferably from 1 to 100 weight parts per 1,000,000 weight parts of components (a), (b), and (c). The preparative method of the present invention comprises the execution of an silylation reaction in the presence of component (c) among the components (a), (b), and (c) as described above. The reaction of this preparative method is preferably carried out under conditions such that the number of moles of aliphatically unsaturated bonds in component (a) exceeds the sum of the number of moles of silicon-bonded hydrogen in component (b) and the number of moles of silicon-bonded hydrogen in component (c). The general range for the reaction temperature is room temperature to 150°C, while the preferred range is 60°C to 150°C in order to shorten the reaction time and to suppress secondary reactions. Solvent can be used in the preparative method of the instant invention in addition to the components described above. Operable solvents are aromatic hydrocarbons such as benzene, toluene, and xylene; acetate esters such as ethyl acetate, and Cellosolve acetate™ (ethylene glycol monoethyl ether acetate); and ethers such as diethyl ether, and tetrahydrofuran. The present invention further relates a to curable composition comprising (a) an aliphatically unsaturated polyester having a number average molecular weight of 300 to 15,000, (b) an organopolysiloxane having at least one silicon-bonded hydrogen atom in its molecule, (c) a silicon compound having in its molecule at least one silicon-bonded hydrogen atom and at least one silicon-bonded hydrolyzable group, (d) a hydrosilylation-reaction catalyst, and (e) a condensation-reaction catalyst, with the proviso that (b) is free of silicon-bonded hydrolyzable groups. Components (a)-(d) are as delineated above including amounts and preferred embodiments thereof. The organopolysiloxane-modified polyester of the present invention contains silicon-bonded hydrolyzable groups originating with component (c). Thus, it is capable of curing at room temperature in the presence of (e) a condensation-reaction catalyst. The catalysts suitable for use as component (e) in the instant invention are exemplified by titanate esters such as tetraisopropyl titanate and tetrabutyl titanate; titanium chelates such as di-n-butoxytitanium bis(ethyl acetylacetate) and diisopropoxytitanium bis(acetylacetate); organotin compounds such as dibutyltin diacetate, dibutyltin octoate, and tin octoate; and organic amines such as guanidine. Component (e) is present in an amount sufficient to initiate the curing reaction with component (e). The amount of component (e) in the compositions of this invention is preferably from .01 to 100 weight parts of the reaction product of (a), (b), (c), and (d), and it is most preferred that component (e) be present in an amount from 0.1 to 50 weight parts per 100 weight parts of the reaction product of components (a), (b), (c), and (d). The organopolysiloxane-modified polyesters of the present invention are useful as a reactive intermediate and are particularly useful as a coating or fiber-treatment agent where properties such as releasability, water repellency, weather resistance, and slip are sought. Textile fibers, fabrics, or yarns such as woven and nonwoven fabrics, wool, cotton, silk, and synthetic fibers can be treated with the compositions of the instant invention. The instant invention will now be explained in working examples. In the examples, parts indicates weight parts, Mn is an abbreviation for number average molecular weight, and Mw is an abbreviation for weight average molecular weight. EXAMPLE 1 The following were introduced into a 1 L four-neck flask equipped with stirrer, thermometer, reflux condenser equipped with distillation column, and nitrogen inlet tube: 290.4 parts isophthalic acid, 174.7 parts neopentyl glycol, 58.7 parts glycerol monoallyl ether, and 20 mL xylene. A reaction was carried out by heating between 220°C to 230°C while stirring. The reaction was stopped when the acid value reached ≤5, and an unsaturated polyester resin was recovered by vacuum distillation of the low boilers. This unsaturated polyester resin had a vinyl content of 2.6 weight% and a carbinol content of 1.6 weight%. 100 parts of this unsaturated polyester resin product and 150 parts toluene were placed in a 500 mL four-neck flask equipped with stirrer, thermometer, reflux condenser, and nitrogen inlet tube, and the contents of the flask were heated to the reflux temperature while stirring. Once the unsaturated polyester resin had dissolved in the toluene, 10 parts hexamethyldisilazane were added in order to trimethylsilylate the carbinol groups in the unsaturated polyester resin. After then reacting for approximately 10 hours while heating at reflux, the toluene and unreacted hexamethyldisilazane were removed by vacuum distillation to yield an unsaturated polyester resin that was solid at room temperature. Table 1 reports the molecular weights (measured by gel permeation chromatography) of the polyester resin before and after silylation. In addition, the chemical shift originating with the silicon-bonded methyl in the silylated polyester resin was evaluated based on the results from proton nuclear magnetic resonance (NMR) analysis. These results confirmed that silylation of the unsaturated polyester resin had developed without the occurrence of secondary reactions during the silylation reaction, for example, without polyester decomposition. The silylated polyester had a vinyl content of 2.4 weight%. pre-silylation post-silylation Mn 3.03 x 10 3 3.34 x 10 3 Mw 6.12 x 10 3 6.37 x 10 3 area (%) 99.2 99.7 EXAMPLE 2 10 parts of the unsaturated polyester resin synthesized in Example 1 (vinyl equivalents = 0.0088 moles) and 148.5 parts toluene were introduced into a 300 mL four-neck flask equipped with stirrer, thermometer, reflux condenser, and nitrogen inlet tube and heated to 70°C while stirring. Once the unsaturated polyester resin had dissolved, 6.5 parts of a dimethylpolysiloxane having the formula (a) described hereinbelow (number average molecular weight = 1,821, SiH equivalents = 0.0036 moles) were added with stirring. This was followed by the addition of 0.02 mL platinum/vinylsiloxane complex (platinum concentration = 4.4 weight%) prepared from chloroplatinic acid and 1,3-divinyltetramethyldisiloxane. A reaction was run for approximately 90 minutes at 70°C. Subsequent to this reaction, organopolysiloxane-modified polyester resin was obtained by the addition with stirring of 15 parts of a 10% tetrahydrofuran solution of trimethoxysilyl-containing dimethylpolysiloxane with formula (b) described hereinbelow (SiH content = 0.0036 moles). The results of infrared spectrochemical (IR) analysis and NMR analysis of this organopolysiloxane-modified polyester resin confirmed it to be a dimethylpolysiloxane-grafted polyester resin in which the dimethylpolysiloxane and trimethoxysilyl-containing dimethylpolysiloxane were grafted. A room-temperature curable composition was prepared by the addition of 0.05 parts tetraisopropyl titanate to 20 parts of this dimethylpolysiloxane-modified polyester resin. This composition was coated on an aluminum test panel, and a cured film was produced by standing at room temperature for 4 days. When toluene was dripped onto the resulting cured film, dissolution did not occur and no swelling of the cured film was observed. These test results served to confirm that this dimethylpolysiloxane-modified polyester resin has undergone crosslinking at room temperature through condensation of its silicon-bonded hydrolyzable groups. EXAMPLE 3 8.2 parts of the unsaturated polyester resin (vinyl equivalents = 0.0072 moles) synthesized in Example 1 and 124 parts tetrahydrofuran were introduced into a 500 mL four-neck flask equipped with stirrer, thermometer, reflux condenser, and nitrogen inlet tube and heated to 62°C while stirring. Once the unsaturated polyester resin had dissolved, 21.3 parts of a dimethylpolysiloxane having the formula (a) as described above (molecular weight = 6,250, SiH equivalents = 0.0034 moles) were added with stirring. This was followed by the addition of 0.02 mL of a platinum/vinylsiloxane complex (platinum concentration = 4.4 weight%) and reacted at 65°C for approximately 90 minutes. 1.5 parts trimethoxysilyl-containing dimethylpolysiloxane (SiH equivalents = 0.0036 moles) having the formula (b) as described hereinabove were then added with stirring. After cooling, 155 parts tetrahydrofuran were added to yield the organopolysiloxane-modified polyester resin product. The results of IR analysis and NMR analysis of this organopolysiloxane-modified polyester resin confirmed it to be a dimethylpolysiloxane-grafted polyester resin in which the dimethylpolysiloxane and trimethoxysilyl-containing dimethylpolysiloxane were grafted. A room-temperature curable composition was prepared by the addition with mixing of 1.6 parts 10% tetrahydrofuran solution of tetraisopropyl titanate to the dimethylpolysiloxane-modified polyester resin product. The resulting tetrahydrofuran solution of the room-temperature curable composition was coated on an aluminum test panel, and a cured film was produced by standing for 4 days at room temperature. Commercial cellophane tape was applied to this cured film and then peeled off at an angle of 180° and a stripping rate of 30 cm/minute using a tensile tester in order to measure the force required for stripping. A low value of 50 g/5 cm was measured. In addition, the water repellency was evaluated by the application of water droplets to the surface of the cured film, and the cured film was thereby determined to have an excellent water repellency. In addition, polyester staple was immersed in the tetrahydrofuran solution of the room-temperature curable composition to give a 0.5% add-on of the room-temperature curable composition. No heating was conducted after this treatment, rather, the polyester staple was allowed to stand at room temperature. The fiber-to-fiber friction coefficients were measured on the treated polyester staple with the following results: static friction coefficient = 0.110, and dynamic friction coefficient = 0.098. The untreated polyester staple had the following values: static friction coefficient = 0.33, and dynamic friction coefficient = 0.23. These results thus confirmed that the dimethylpolysiloxane-modified polyester resin of this present invention makes an excellent fiber-treatment agent. EXAMPLE 4 2.5 parts of the unsaturated polyester resin synthesized in Example 1 (vinyl equivalents = 0.0022 moles) and 53.1 parts tetrahydrofuran were placed in a 100 mL four-neck flask equipped with stirrer, thermometer, reflux condenser, and nitrogen inlet tube and were heated to 60°C while stirring. Once the unsaturated polyester resin had dissolved, 3.4 parts of a dimethylpolysiloxane with formula (a) above (molecular weight = 4,000, SiH equivalents = 0.00085 moles) were added with stirring. This was followed by the addition of 0.02 mL of the platinum/vinylsiloxane complex with platinum concentration = 4.4 weight%. After a reaction for approximately 90 minutes at 65°C, 3 parts of a 10% tetrahydrofuran solution of trimethoxysilyl-containing silicone compound having the following formula (c) (SiH equivalents = 0.0011 moles) were added with stirring. Further reaction at 65°C yielded an organopolysiloxane-modified polyester resin. The results of IR and NMR analyses of this organopolysiloxane-modified polyester resin confirmed it to be a dimethylpolysiloxane-grafted polyester resin in which dimethylpolysiloxane and trimethoxysilyl-containing dimethylpolysiloxane were grafted. A room-temperature-curable composition was prepared by the addition of 0.10 part tetraisopropyl titanate to 20 parts of this dimethylpolysiloxane-modified polyester resin. This room-temperaturecurable composition was applied on an aluminum test panel, and a cured film was produced by standing for 4 days at room temperature. When toluene was dripped onto the resulting cured film, dissolution did not occur and no swelling of the cured film was observed. Commercial cellophane tape was applied on this cured film and then peeled off at an angle of 180° and a stripping rate of 30 cm/minute using a tensile tester in order to measure the force required for stripping. A low value of 50 g/5 cm was measured. Moreover, no transfer of dimethylpolysiloxane to the cellophane tape was observed. Finally, the water repellency was evaluated by the application of water droplets to the surface of the cured film, and the cured film was thereby determined to have an excellent water repellency.

Claims: An organopolysiloxane-modified polyester graft copolymer comprising: (a) a polyester segment selected from aliphatic polyesters or aromatic polyesters. having a number average molecular weight of 300 to 15.000. (b) an organopolysiloxane segment derived from trimethylsiloxy-terminated dimethylpolysiloxanes, trimethylsiloxy-terminated methylalkyl (C 2 -C 10 ) polysiloxanes, or trimethylsiloxy-terminated methylphenylpolysiloxanes, and (c) a silicon segment having at least one silicon-bonded hydrolyzable group in the segment, selected from silicon-bonded alkoxy groups, silicon-bonded acetoxy groups, and silicon-bonded methyl ethyl ketoxime groups, derived from a silicon compound having in its molecule at least one silicon-bonded hydrogen atom and at least one silicon-bonded hydrolyzable group, selected from silicon-bonded alkoxy groups, siliconbonded acetoxy groups, and silicon-bonded methyl ethyl ketoxime groups, with the proviso that the organopolysiloxane segment (b) does not contain silicon-bonded hydrolyzable groups. Polyestergraft copolymer according to claim 1 wherein (c) is derived from trimethoxysilane, methyldimethoxysilane, triacetoxysilane, and tri(methyl ethyl ketoxime)silane. A method for preparing an organopolysiloxane-modified polyester graft copolymer comprising reacting (a) an aliphatically unsaturated polyester selected from aliphatic polyesters or aromatic polyesters, having a number average molecular weight of 300 to 15.000, (b) an organopolysiloxane selected from trimethylsiloxy-terminated dimethylpolysiloxanes, trimethylsiloxy-terminated methylalkyl (C 2 -C 10 ) polysiloxanes, and trimethylsiloxy-terminated methylphenylpolysiloxanes, having at least one silicon-bonded hydrogen atom in its molecule, and (c) a silicon compound having in its molecule at least one silicon-bonded hydrogen atom and at least one silicon-bonded hydrolyzable group selected from silicon-bonded alkoxy groups, silicon-bonded acetoxy groups, and silicon-bonded methyl ethyl ketoxime groups, in the presence of (d) a hydrosilylation-reaction catalyst, with the proviso that (b) is free of silicon-bonded hydrolyzable groups. A method according to claim 3, wherein (c) is selected from trimethoxysilane, methyldimethoxysilane, triacetoxysilane, and tri(methyl ethyl ketoxime)silane. A method according to claim 3, wherein the hydrosilylation-reaction catalyst is selected from platinum, palladium, rhodium, ruthenium, cobalt, and nickel. A method according to any of claims 3-5, wherein further a solvent is present. A room temperature curable composition comprising an organopolysiloxane-modified polyester graft copolymer according to claim 1 or 2, and (e) a condensation reaction catalyst. A composition according to claim 7, wherein the composition further comprises a solvent. A composition according to claim 7 or 8, wherein (e) is selected from titanate esters, titanium chelates, organotin compounds, and organic amines. A fiber treated with the compositions of any of claims 7-9.

Inventors: MIKAMI RYUZO, ONA ISAO, MIKAMI, RYUZO, ONA, ISAO, MIKAMI, RYUZO, RES. AND DEV., DOW CORNING TORAY, ONA, ISAO, RES. AND DEV., DOW CORNING TORAY
Applicants: DOW CORNING TORAY SILICONE, DOW CORNING TORAY SILICONE COMPANY, LIMITED
Application year: 1993
Main classification: C08G77
IPC codes: C08K5, C09D183, C08L83, C08G63, D06M13, D06M15, C08G77