MXPA97008019A - Union of anionic polymers with tri alcoxisilanos that have silicon-hydrog links - Google Patents

Abstract

A high yield of the three-branched radial anionic polymers is produced by the process of joining the metal-terminated anionic polymers with a trialkoxylan having a silicon-hydrogen bond, preferably trimethoxysilane. The metal-terminated anionic polymer is preferably produced by initiating the polymerization with a protected functional initiator which is readily converted to the terminal hydroxyl groups or derivatives thereof, and finds use in adhesives, sealants, and coatings.

Description

UNION DS. ANIONIC POLYMERS WITH TRIALC0XI3ILAN03 THAT HAVE SILICON-HYDROGEN GLYCLES Field of the Invention This invention relates to the union of anionic polymers and functionalized radial polymers, used as components in adhesives, sealants, and coatings. 10 Field of the Invention Anionic polymerization of conjugated dienes with lithium initiators, such as sec-butyllithium, and hydrogenation of residual unsaturation have been described in many references including U.S. Patent Specification. No. Re. 27,145 which teaches a relationship between the amount of the 1,2-addition of butadiene and the temperatures of glass transition of the hydrogenated butadiene polymers. Any polymerization using protected functional primers having the structure:: > 5 Ref.25948 are described in US Patent Specification No. 5,331,058 wherein R1, R2, and R3 are preferably alkyl, alkoxy, aryl, or alkaryl groups having from 1 to 10 carbon atoms, and A 'is preferably a linking group by middle of a bridge, straight or branched chain, having at least 2 carbon atoms. The initiators of the general structure (1), in which R1 = t-butyl and R2 = R3 = methyl, ethyl, or n-propyl and A 'is a linking group by means of an unsubstituted or substituted propyl bridge with alkyl or a linking group via an unsubstituted or substituted alkyl octyl bridge, it was later shown that they will be preferred due to their higher activity in US Patent Specification No. 5,391,663. Polymerization with such a protected functional initiator, followed by coronation at the ends to produce a second terminal functional group, produces difunctional polymers which can sometimes be prepared by crowning the prepared polymers at the ends with difunctional initiators such as 1-4. dilithiobutane and lithium naphthalide. However, the use of a protected functional primer allows the formation of heterofunctional polymers having at least two different terminal functional groups on each difunctional molecule. A preferred way to prepare the difunctional polymers described in United States of America Patent Specification No. 5,416,168 is to use a protected functional initiator having the structure: CH3 I CH3-Si-0-CH2-A "-CH2-LÍ I (A) CH3 wherein A "is a cyclohexyl group or a group -CR'R", wherein R 'represents a linear alkyl group having from 1 to 10 carbon atoms and R "represents a hydrogen atom or a linear alkyl group having from 1 to 10 carbon atoms The compounds of the structure (A) initiate the polymerization of the conjugated monomers at moderate polymerization temperatures.The protected functional group survives the hydrogenation of the conjugated dienes polymers and is easily removed by the hydrolysis in the presence, for example, of the methanesulfonic acid The initiators of the structure (A) can be used to manufacture telechelic polymers by crowning the ends with ethylene oxide or oxetane.

The joining of anionic polymers to make radial polymers is described in many references, including U.S. Patent Specification No. 4,185,042 which teaches that the difficulty to obtain complete binding with tetramethoxysilane or trimethoxymethylsilane is overcome using an epoxide group with two or three alkoxy groups to make the radial anionic polymers. The epoxide group reacts readily with a lithium-terminated anionic polymer leaving a hydroxyl group at the binding site. A more efficient bonding can also be achieved using chlorosilanes, such as trichloromethylsilane. However, the by-product of the binding reaction, LiCl, can be a problem in subsequent process steps, particularly if the product is to be hydrogenated. It is an object of the present invention to join the anionic polymers in a high yield to form the radial polymer without introducing the hydroxyl functionality into the binding site. The achievement of the established object could be the most beneficial for the hydrogenated radial anionic polymers that have only terminal hydroxy groups.

Detailed description of the invention The present invention provides a radial anionic polymer obtainable by a process comprising the process steps of preparing a linear anionic polymer terminated in a metal, containing protected functional groups, by the polymerization of a conjugated diene, such as butadiene or isoprene, or a monovinyl aromatic compound, such as styrene, or combinations thereof, using a metal-protected functional initiator, such as a protected, functional mono-lithium initiator, and joining a plurality of the linear anionic polymers using a trialkoxysilane having a silicon-hydrogen bond. The present invention further comprises the process for manufacturing a radial anionic polymer of the invention which comprises these process steps. The process of the lithium initiator is well known and is described in U.S. Patent Specifications. Nos. 4,039,593 and Re. 27,145. Typical, active polymeric structures that can be manufactured with lithium initiators include: X-B-Li X-B / A-Li X-A-B-Li X-B-A-Li X-B-B / A-Li X-B / A-B-Li X-A-B-A-Li wherein B represents polymerized units of one or more conjugated diene hydrocarbons, A represents polymerized units of one or more vinyl aromatic compounds, B / A represents randomly polymerized units of the conjugated diene hydrocarbons and vinyl aromatic monomers, and X is the residue of the lithium initiator. In the present invention, X is preferably a trimethylsilyl ether group as described below and the cleavage or cleavage of trimethylsilyl ether leaves a primary alcohol group similar to neopentyl in this position. These primary alcohols have a different reactivity than other primary alcohol groups which will lead to different reaction rates for the ends of the chain with the diisocyanates and the dicarboxylic acids. This difference in reactivity velocities could be very useful in the design of materials where gradual polymerization is desired. Anionic polymerization of the conjugated dienes and other unsaturated monomers using the protected functional initiators having the structure R1R2R3Si-0-A '-Li (Structure 1.) is described in US Patent Specification No. 5,331,058 wherein R1, R2 , and R3 are preferably alkyl, alkoxy, aryl, or alkaryl groups having from 1 to 10 carbon atoms, and A 'is preferably a linking group by means of a straight or branched chain bridge having at least 2 carbon atoms. A preferred protected functional initiator for making the homopolymers of the conjugated dienes and the block or random copolymers of the conjugated dienes and vinyl aromatics have a trimethyl silyl protecting group with the structure: CH3 I CH3-Si-0-CH2-A "-CH2-LÍ | (A) CH3 Where A "represents a cyclohexyl group or a group -CR 'R" -, where R' represents a linear alkyl having from 1 to 10 carbon atoms and R "represents a hydrogen atom or a linear alkyl group having from 1 to 10 carbon atoms The compounds of structure (A) initiate the polymerization of conjugated dienes monomers such as butadiene and isoprene at moderate polymerization temperatures.The protected functional group survives the hydrogenation of the diene polymers conjugates and is easily removed by hydrolysis in the presence of, for example, methanesulfonic acid The preferred initiators used in the present invention are similar to s-butyllithium with respect to the economical operating temperature and low amounts of the inactive initiator and a controlled, uniform level of 1,2-addition of the diene in the produced polymer, however, preferred initiators have the advantage of placing a group of silyl ether at the beginning of the polymer chain which serves as a "masked" or "protected" alcohol, capable of conversion to a group of alcohol of the neopentyl, primary type, after the polymerization is completed by reaction with acids or bases under low cost, mild conditions, or as described in the Patent specification International No. 91/12277. Although the initiators described in US Patent Specification No. 5,331,058 could generally produce, after polymerization and deprotection, a polymer having a primary alcohol functionality, a polymer having a primary alcohol functionality of the neopentyl type, obtained from the initiators of Structure (A), must have improved thermal stability and the condensation polymers derived therefrom must have improved hydrolytic stability. The condensation polymers derived from the products made with these initiators must also have an improved hydrolytic stability. The improved thermal stability of neopentyl alcohol and the hydrolytic characteristics of its derivatives are summarized in Advanced Organic Chemistry, Third Edition, by J. March, John Wiley & amp;; Sons, New York (1985) (see pages 285, 299, 390, 514, 944, 955, 959, and references therein). It is reasonable that polymers having this special structure could have similarly improved properties. The initiators used in the present invention are very active at room temperature and the polymerization is preferably initiated at a temperature in the range from 15 ° C to 60 ° C, more preferably from 30 ° C to 40 ° C. Generally, it can be contemplated to keep the polymerization temperature below 100 ° C; Above this temperature, lateral reactions that change the microstructure and limit the efficiency of the joint can become important. The polymerizations can be carried out over a range of solids levels, preferably in the range from 5% to 80% by weight of the polymer, more preferably from 10% to 40% by weight. For polymerizations with a high solids content, it is preferable to add the monomer in increments to avoid exceeding the desired polymerization temperature. If the initiator is to be added to the complete monomer charge, it is preferable to operate the polymerization at a level in the range of 10% to 20% solids. It is preferable to add the alkoxysilanes of the present invention to a ratio of an alkoxy group per active chain. That is, to produce a radial polymer with three branches, one mole of trialkoxysilane is added for every three moles of the polymeric lithium ion. It is preferable to carry out the binding reaction at a temperature in the range from 30 ° C to 80 ° C. It is also preferable to add the binding agent as soon as the polymerization is complete. If the polymeric lithium ion is aided or left at this temperature for prolonged periods of time, limiting reactions that limit bonding may occur. When the conjugated diene is 1,3-butadiene and when the conjugated diene polymer is hydrogenated, the anionic polymerization of the conjugated diene hydrocarbons is typically controlled with the structure modifiers such as diethyl ether or glyme (1, 2-diethoxyethane) to obtain the desired amount of 1,2 addition. As described in US Patent Specification No. Re 27,145, the level of 1,2 addition of a butadiene polymer or copolymer can greatly affect the rheology and elastomeric properties of the polymer after hydrogenation. The hydrogenated polymers exhibit thermal stability and resistance to improved environmental factors, in the adhesive, sealant or coating, finishes. The 1,2-addition of the 1,3-butadiene polymers having terminal functional groups influences the viscosity of the polymers as described in greater detail below. A 1.2 addition of about 40% is achieved during the polymerization at 50 ° C with at least 6% by volume of diethyl ether or 1000 ppm of glyme. In general, vinyl contents in this range are desirable if the product is to be hydrogenated, while low vinyl contents are preferred if the polymer is to be used in its unsaturated form. The protected functional primers are preferred as described below and are prepared as described in US Patent Specification No. 5,331,058. A variety of processes for the removal of protective groups are already known; for a review, see T. W. Greene, "Protective Groups in Organic Synthesis," J. Wiley and Sons, New York, 1981. A preferable process could involve easily handled, relatively low toxic, and economic reagents. In a preferred process, the preferred trimethyl silyl group is removed by the reaction of the polymer solution with from 1 to 10 equivalents (end silyl groups of the base) of the strong organic acid, preferably methanesulfonic acid (MSA), in the presence from 0.1% to 2% by weight of water and from 5% to 50% by volume of isopropanol (IPA) at 50 ° C. The process of the invention can lead to the release of fine particles of lithium bases which are preferably removed prior to hydrogenation, if any, as described in U.S. Patent Specification. No. 5,166,277. The lithium bases can interfere with the hydrogenation of the polymer, especially if the hydrogenation is to be carried out at a high solids content. However, as detailed in the Examples, an acceptable hydrogenation can be achieved without the removal of lithium when the binding agents of the present invention are employed. The hydrogenation of at least 90%, preferably at least 95%, of the unsaturation in the low molecular weight butadiene polymers is preferably achieved with the nickel catalysts as described in U.S. Patent Specifications. Nos. Re. 27,145 and 4,970,254 and U.S. Patent Specification. No. 5,166,277. The preferred nickel catalyst is a mixture of nickel 2-ethylhexanoate and triethylaluminum. It is preferable to extract the nickel catalyst after hydrogenation, by stirring the polymer solution with aqueous phosphoric acid (from 2 to 30 weight percent), at a volume ratio of 0.5 parts of aqueous acid with respect to 1 part of the solution polymer, at 50 ° C for 30 to 60 minutes while being sprayed with a mixture of oxygen in nitrogen. The presence of elevated levels of lithium chloride during acid extraction, which could occur if a chlorosilane binding agent is used, requires special engineering considerations. Due to the high corrosiveness of acidic aqueous solutions that have a high chloride content towards carbon steel and most stainless steel alloys, the use of relatively expensive special glass or alloys could be recommended for surface contact of the extraction vessel with the acid. Conjugated, radial, saturated or unsaturated dienes polymers having approximately three terminal functional groups, are selected from the hydroxyl, carboxyl, phenol, epoxy, and amine groups; these latter functional groups can be obtained from the additional derivation of the hydroxyl groups. These products can be used without solvents when the viscosity of the polymer is less than 500 poises at the mixing and application temperature. Radial, three-branched hydrogenated butadiene or isoprene polymers, having two terminal hydroxyl groups per molecule and a viscosity of less than 500 poises at the mixing and application temperatures, are produced by limiting the molecular weight of the maximum point to a range from 500 to 20,000 and limiting the 1,2-addition of the hydrogenated butadiene to an amount in the range from 30% to 70%, preferably from 40% to 60%. After polymerization and, optionally, hydrogenation and washing of the polymer, the trimethylsilyl group at the front of the preferred polymer chain is removed to generate the hydroxyl functional group of the neopentyl, primary, desired type. This step is often referred to as a checkout. A variety of the processes for the removal of the silyl protecting group are already known; for a review, see TW Greene, "Protective Groups in Organic Synthesis," J. Wiley and Sons, New York, 1981. Deprotection preferably involves easily manipulable reagents, relatively low toxicity, economics, and reduced cost process conditions, soft. The reaction with tetrabutylammonium fluoride in tetrahydrofuran (THF), as described in International Patent Specification No. WO 91 112277, is disadvantageous because of the high cost and toxicity of the reagents. In a preferred process, the trimethylsilyl group is removed after the hydrogenation and during the aqueous washing of the acid for the removal of the spent Ni / Al hydrogenation catalyst. This technique avoids the cost associated with a separate process step for check out. For the preparation of an unsaturated polymer wherein the extraction of the hydrogenation catalyst is not required, hydrolysis in the presence of methanesulfonic acid, as described above, is preferred. For some applications, such as coatings prepared by curing the polymer with amino resins in the presence of a strong organic acid catalyst, it may be preferable to use the polymer in its "protected" form. The viscosity of the protected polymer is lower and conditions such as those described above must effect deprotection (generate alcohol) during curing. The conjugated diene polymers produced as described above have the conventional utilities for terminal functionalized polymers, such as the formation of adhesives, coating and sealing agents. Additionally, polymers can be used to modify polyurethanes, polyesters, polyamides, polycarbonates, and epoxy resins. A preferred radial anionic polymer has terminal functional groups and is produced by the process comprising the steps of polymerizing linear lithium-terminated anionic polymers from conjugated dienes, such as isoprene or butadiene, or combinations of conjugated dienes and aromatics of monoalkenyl, such as styrene, using a protected functional initiator having the structure: CH3 CK3-Si-0-CH2-A "-CH2-LI (A) CH3 wherein A "represents a cyclohexyl group or a group -CR'R" -, wherein R 'represents a linear alkyl having from 1 to 10 carbon atoms and R "represents a hydrogen atom or a linear alkyl group having from 1 to 10 carbon atoms, join the linear anionic polymers with a trialkoxysilane having a silicon-hydrogen bond, preferably trimethoxysilane, hydrogenate the polymerized conjugated diene, and react the hydrogenated radial polymer with a compound that replaces the trimethylsilyl groups of the initiator of lithium with hydrogen to give the terminal hydroxyl groups The most preferred process for manufacturing the terminally functionalized radial polymer uses the initiator having the following structure: CH3 CH3 CH3-S IÍ-O-CH2-CI-CH2-LÍ (B) I I CH3 CH3 (3-lithium-2,2-dimethyl-1-trimethylsilyloxypropane) to produce the linear conjugated diene polymers having a molecular weight of the maximum point in the range from 500 to 200,000, more preferably from 500 to 20,000. After binding with trimethoxysilane, the polymers can be unsaturated when the 1-2 addition is in the range of 5 to 95% or hydrogenated when the 1.2 addition is in the range of 30% to 70%. The radial polymers preferably have in the range from 2.75 to 3.0, more preferably from 2.95 to 3.0, terminal hydroxyl groups per molecule.

The polymers of the present invention, especially the above preferred forms, are useful in adhesives (including pressure sensitive adhesives, contact adhesives, laminating adhesives and assembly adhesives), sealants (such as architectural urethane sealants), coatings (such as automotive top coatings, epoxy metal primers, polyester coil coatings, and alkyd maintenance coatings), films (such as those that require heat and solvent resistance), and thermosetting and thermoplastic parts molded and extruded (for example injection molded polyurethane rolls or cylinders, thermoplastics, or automotive facies and dampers, thermosetting, injection molded, by reaction) and consequently the present invention also provides a composition suitable for such uses, which comprises a polymer d e the present invention. The additional components are usually incorporated in such compositions. A composition of the present invention may contain plasticizers, such as rubber or rubber extender plasticizers, or composition oil or organic or inorganic pigments and dyes. Oils of rubber or rubber composition are well known in the art and include both oils with a high content of saturated materials and oils with a high aromatic content. Preferred plasticizers are highly saturated oils, for example TUFFLO 6056 and 6204 oil made by Garco and process oils, for example SHELLFLEX 371 oil made by Shell (TUFFLO and SHELLFLEX are registered names). The amounts of the oil of rubber or rubber composition employed in such compositions can vary from 0 to 500 phr, preferably from 0 to 100 phr, and more preferably from 0 to 60 phr. The original components of the present invention are stabilizers which inhibit or retard degradation by heat, oxidation, film formation and color formation. The stabilizers are typically added to commercially available compounds to protect the polymers against degradation by heat and oxidation during preparation, use and storage at elevated temperature of the composition. Various types of fillers and pigments can be included in a coating or sealing formulation. This is especially true for exterior coatings or sealants in which the fillers are added not only to create the desired attraction but also to improve the performance of the coatings or sealants such as their resistance to environmental agents. A wide variety of fillers can be used. Suitable fillers include calcium carbonate, clays, talcs, silica, zinc oxide, and titanium dioxide. The amount of the filler is usually in the range of 0 to 65% by weight based on the solvent-free portion of the formulation, depending on the type of filler used and the application for which the coating or sealant is proposed. A particularly preferred filler is titanium dioxide. The conjugated, trihydroxylated diene polymers of the present invention may also be blended or combined with other polymers to improve their flexibility and / or impact resistance. Such polymers are generally condensation polymers including polyamides, polyurethanes, vinyl alcohol polymers, vinyl ester polymers, polysulfones, polycarbonates and polyesters, including those similar to polyacetones, which have a recurring ester bond in the molecule, and those similar to polyalkylene acrylates, including polyalkylene terephthalates, having a structure formed by the polycondensation of a dicarboxylic acid with a glycol. The mixtures or combinations can be made in the reactor or in a subsequent composition step. The present invention is further illustrated by the following examples. The molecular weights of the maximum point are measured using gel permeation chromatography (CPG) calibrated with polybutadiene standards having known molecular weights of the maximum point. The solvent for the CPG analyzes was tetrahydrofuran. The percentage of the 1,2-additions of the polybutadiene, the molecular weight, and the extent of hydrolysis of the protected alcohol were measured by 13 C NMR or 1 H NMR in the chloroform solution. High Resolution Liquid Chromatography (HPLC) can also be used to determine the relative amounts of the desired trihydroxy material (triol), and the mono-hydroxy or di-hydroxy material, which could have resulted from incomplete binding. Where used, the separation by CLgAR was carried out with a phase column of DIOL of 250 mm x 4.6 mm x 5 microns using gradient graduated heptane / tetrahydrofuran. An evaporative light scattering or scattering detector can be used to quantify the sample.

Examples Example 1 The reaction of the preferred lithium initiator of US-A-5, 391, 663 with the polymerization effectively initiated by butadiene and the reaction of the active polymer product with trimethoxysilane produced, after isolation, a high yield of 1 , 4-polybutadienil triol superior, with three branches. A solution of 3- (t-butyldimethylsilyloxy) -1-propyllithium (RLi) (105.71 g of the solution, 12.8% by weight of RLi, 0.075 mole of RLi) in cyclohexane was added, under nitrogen, to a solution of butadiene monomer (100 g, 1.85 moles) of the degree of polymerization, in cyclohexane (856 g) with vigorous stirring in a glass autoclave at 30 ° C. The resulting exothermic reaction raised the temperature of the solution to 47 ° C in about 37 minutes. The temperature was then increased to 60 ° C. After a total reaction time of 137 minutes, a small sample was removed and then quenched with methanol, then 3.1 g (0.025 mol) of trimethoxysilane was added to the autoclave. The temperature of the reaction was increased to 70 ° C. After 1 hour, the temperature was lowered to 40 ° C and 3.3 ml of methanol was added. A large amount of the white precipitate (lithium methoxide) has formed in the course of the reaction. The solution is washed with 200 ml of 3 wt% aqueous phosphoric acid at about 57 ° C, and a sample is dried for analysis. The sample collected prior to the addition of the binding agent was found to have a numerical average molecular weight (Mn) of 1.470 when measured by a Nuclear Magnetic Resonance of 13C which compares the ratio of the carbon signal that is attributed to the segment of the initiator alkyl with the total carbon signal for the sample; this compares favorably with the expected value of 1,500. The analysis of this sample to verify the vinyl content, also using an NMR technique, found that 11% of the butadiene has been added by the 1,2-polymerization producing a pendant vinyl unsaturation with the remainder added by the polymerization 1, 4 that provides the chained unsaturation species. The numerical average molecular weight as measured by a gel permeation chromatography (CPG) technique was found to be 1,200. The true value is probably lower because this molecular weight is close to the linear operating limit of the column. After the binding reaction, a single peak was observed and the Mn was increased to 2,800, approximately three times the molecular weight of the branch. After decanting the aqueous layer, a solution containing 232 ml of isopropanol, 12.7 ml of methanesulfonic acid and 1.7 ml of water was added to the polymeric cement. The reaction was allowed to proceed at about 55 ° C for 2.5 hours. The cement was washed with dilute aqueous potassium carbonate and then with water, and dried on a rotary evaporator. The analysis of 13C Rg was consistent with the 97% hydrolysis of silyl ether. The HPLC chromatogram of this product consisted of two peaks or maximum values; 90% of the area was at a very high retention time, consistent with the expected triol product, the remaining 10% was at the retention time assigned to the diol. No mono-functional or non-functional material was detected.

Example 2 A radial butadiene polymer was prepared using the preferred initiator, 3-lithium-2,2-dimethyl-1-trimethyl-silyloxypropane and hydrogenated using a Ni / Al catalyst; the saturated polymer product was deprotected under the conditions used to extract the spent hydrogenation catalyst yielding the desired hydrogenated poly (ethylene / butylene) triol. A solution of 3-lithium-2,2-dimethyl-1-trimethylsilyloxypropane (RLi) (71.54 g of the solution, 11.6% by weight of RLi, 0.05 mole of RLi) in cyclohexane was added, under nitrogen, to a solution of the butadiene monomer of the polymerization degree (100 g, 1.85 mmol) in a mixed diethyl ether / cyclohexane solvent (712 g of cyclohexane / 100 g of diethyl ether) with vigorous stirring in a glass autoclave at 30 ° C. The resulting exothermic reaction raised the temperature of the solution to 62 ° C in about 15 minutes. 2.04 g (0.017 moles) of trimethoxysilane are added to the autoclave at this time. The temperature is maintained at about 40 ° C for 40 minutes and then 2.2 ml of methanol are added. A large amount of the white precipitate (lithium methoxide) has formed in the course of the reaction. The CPG analysis of the bound product indicated a single peak with an Mn of 5,000, which is in agreement with the expected triol molecular weight of 6,000. Although no sample was taken of the "branching" prior to binding, the ratio of the initiator residues ("X" in the previous structures) to the monomeric butadiene residues, determined by XH, NMR, may be used. to estimate the numerical average molecular weight of the branch.

The value of the measurement of 2,000 ± 100 is in accordance with the expected value of 2,000. The hydrogenation catalyst (Ni / Al) for this experiment was previously prepared by combining the 2-ethylhexanoate with triethylaluminum in cyclohexane in amounts sufficient to give a ratio of 2.5 moles of Al to 1 mole of Ni. The polymeric cement was transferred to a 500 cc steel autoclave and sprayed with hydrogen at 40 ° C. No filtration or centrifugation step was used to remove the precipitated lithium methoxide, but most of it has settled during rest and was not transferred. The reactor was then pressurized to 4,826 kPa (700 psig) with hydrogen and the Ni / Al catalyst was added in aliquots. The temperature of the reaction was maintained between 60 ° C and 80 ° C. A sufficient amount of the Ni / Al catalyst was eventually added to bring the concentration of the total Ni solution to 200 ppm. After 2 hours of hydrogenation, an aliquot was removed and analyzed later to verify the C = C portions that did not react, using an ozone titration technique; at this time the catalyst concentration was 200 ppm. This analysis found that up to 98% of the starting polybutadienyl unsaturation has been hydrogenated (0.14 meq / g). The hydrogenation continued after increasing the catalyst concentration to 290 ppm. The analysis of the final product indicated up to 99% of the hydrogenation of the unsaturation (0.03 meq / g). The majority of the hydrogenation catalyst settled during rest. 323 g of the essentially clear cement were transferred to a resin pan and the protecting groups were removed by hydrolysis with methanesulfonic acid and water in the presence of isopropanol (3.14 g, 1.5 g and 77 g, respectively) as described in Example 1. After washing this solution with water and removing the solvent, a colorless, clear, viscous liquid was obtained; the product became cloudy when cooled due to a light crystallinity imparted by the 1.4 hydrogenated repeat units. There is no evidence of residues of any of the lithium salts or the hydrogenation catalyst. 1 H RgMN indicated 97% hydrolysis of the silyl ether protecting groups with respect to the desired hydroxyl product.

It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention. Having described the invention as above, property is claimed as contained in the following

Claims (9)

1. A radial anionic polymer, characterized in that it can be obtained by a process comprising the steps of: preparing a metal-terminated linear anionic polymer, containing protected functional groups, by the polymerization of a conjugated diene, a monovinyl aromatic compound, or a combination thereof, using a protected functional metal initiator; and joining a plurality of the linear anionic polymers using a trialkoxysilane having a silicon-hydrogen bond.

2. A radial polymer according to claim 1, characterized in that the trialkoxysilane is trimethoxysilane.

3. A radial polymer according to claim 1 or claim 2, characterized in that the metal initiator is a protected functional initiator of the general formula CH3 CH3-S Ii-0-CH2-A "-CH2- i I (A) CH3 wherein A" represents a cyclohexyl group or a group -CR'R ", wherein R 'represents a linear alkyl group having from 1 to 10 carbon atoms and R "represents a hydrogen atom or a linear alkyl group having from 1 to 10 carbon atoms.

4. A radial polymer according to claim 3, characterized in that A "in the initiator is -CR'R" - and R "is methyl.

5. A radial polymer according to claim 4, characterized in that R 'is methyl.

6. A radial polymer according to any of claims 1 to 5, characterized in that the radial polymer comprises or contains polymerized conjugated dienes, and, following bonding, the following additional steps are carried out: hydrogenating the polymerized conjugated diene; and reacting the hydrogenated radial polymer with a compound that replaces the trimethylsilyl groups of the lithium initiator with hydrogen, to give the terminal hydroxyl groups.

7. A radial polymer according to claim 6, characterized in that the linear anionic polymer comprises the homopolyisoprene or the homopolybutadiene having an average molecular weight in the range of 500 to 200,000, more preferably from 500 to 20,000, when measured with the chromatography of gel permeation calibrated with polybutadiene standards.

8. A process for the preparation of a radial anionic polymer according to claim 1, characterized in that it comprises the process steps that were described in any of claims 1 to 7.

9. A composition for use in adhesives, sealants and coatings, films and thermosetting and thermoplastic molded and extruded parts, characterized in that it comprises a polymer according to any of claims 1 to 7.