MXPA97002588A - Adhesives and sealants, structural, sensitive to the pressure, based on telekelic / heterotelequelicos polymers with curing systems d - Google Patents

Abstract

The present invention relates to compositions for adhesives and sealants, structural, pressure sensitive, comprising: (a) a system comprising 95 to 15% by weight of a telechelic polymer and 5 to 85% by weight of a heterotelequélico polymer, where at least one of the functionalities that is found in mimes is the same as the functionality found in the telechelic polymer, and (b) a dual curing system where an element of the curing system cures the telechelic polymer at a temperature close to room temperature, such that a pressure-sensitive adhesive or sealant is formed, and the other element cures the telechelic polymer, upon baking at least 100 ° C, to form an adhesive composition or sealant, structural. In a preferred embodiment, the polymer system is comprised of a diol or polyol polymer, telechelic, with hydroxyl functionality, and the heterotelechlic polymer is a monohydroxylated polydiene polymer that also has olefin functionality, converted to epoxide. The dual curing system is preferably comprised of an isocyanate-based curing agent to cure the hydroxyl groups at room temperature, to form a pressure sensitive adhesive or sealant, and an amino resin, to cure the epoxy functionality, when baked, and form an adhesive or sealant, structure

Description

ADHESIVES AND SEALANTS, STRUCTURAL, SENSITIVE TO THE PRESSURE, BASED ON TELEQUÉLICOS / HETEROTELEQUÉLICOS POLYMERS WITH DUAL CURING SYSTEMS FIELD OF THE INVENTION The present invention relates to pressure sensitive adhesive compositions, which can be further cured after being applied to a substrate, causing them to behave as structural adhesives. More particularly, the present invention provides adhesive and sealant compositions, based on a mixture of a telechelic polymer having hydroxyl functionality, with a terotelequic polymer having functionality, both hydroxyl and other, and a curing system dual such as an isocyanate and a melamine.

BACKGROUND OF THE INVENTION Pressure-sensitive adhesives, based on conjugated diene block copolymers, and / or REF: 24387 vinylaromatic hydrocarbons, are well known. They have the particular advantage that they provide an instantaneous bond under light pressure. The limitation of pressure sensitive adhesives is that they lack cohesive force to withstand large loads. The structural and semi-structural adhesives, based on these polymers, are also well known. Its advantage is that they cure to give adhesives that can withstand quite high loads. Their disadvantage is that they must be applied as liquids, in order to achieve a good union and therefore the assembly must be held until the adhesive hardens, usually by chemical curing, but sometimes by cooling the melt. It would be very advantageous to provide a pressure-sensitive adhesive which exhibits an instantaneous bond and which at the same time has sufficient cohesive strength in such a way that the requirements for fasteners are minor or unnecessary, and which additionally cures with some subsequent treatment, thus increasing its cohesive strength in such a way that it becomes a structural or semi-structural adhesive. The present invention provides such a composition, which is useful in both adhesives and sellers.

DESCRIPTION OF THE INVENTION The present invention relates to structural, pressure sensitive, sealant and adhesive compositions, comprising (a) a polymer system comprising from 95 to 15% by weight of a telechelic polymer and from 5 to 85% by weight of a heterotelequin polymer, wherein at least one of the functionalities of the telechelic polymer is the same as the functionality of the telechelic polymer and (b) a dual curing system wherein an element of the curing system cures the telechelic polymer to conditions close to environmental conditions forming an adhesive or a sealant, sensitive to pressure, and the other element cures the heterotelecholic polymer upon baking at least at 100 ° C to form a structural adhesive or sealant composition.

In a preferred embodiment, the telechelic and heterotelequinic polymers contain hydroxyl functionality and the other functionality of the heterotelecholic polymer is selected from the group consisting of olefinic epoxy groups, glycidyl ether epoxy groups, C = C unsaturation and acrylic unsaturation. In a more preferred embodiment the polymer system is comprised of a hydroxyl-functional, telechelic polyol-diol or polyol polymer, and the heterotelequelic polymer is a monohydroxy polydiene side polymer that also has an olefin functionality, converted to epoxide. The dual curing system is preferably comprised of an isocyanate-based curing agent to cure the hydroxyl groups, at room temperature, to form a sealant or a pressure sensitive adhesive, and an amine resin to cure the Epoxy functionality, when baked, to form a structural adhesive or sealant. The polymer system is comprised of both a telechelic polymer and a heterotelequic polymer. A telechelic polymer is one that has a particular type of functional group attached near the ends of the molecule. The telechelic polymers are typically monoles, diols, triols and star polyols. The telechelic polymers can be manufactured through well-known polymerization processes, with ring opening, of cyclic monomers, with an initiator, typically a polyfunctional alcohol. Among the examples is the polymerization, with ring opening of monomers such as ethylene oxide, propylene oxide, butylene oxide, or caprolactone, initiated with ethylene glycol to give diols, or by glycerol to give triols. Other well-known processes for manufacturing telechelic polymers is by anionic polymerization with a polyfunctional initiator, followed by the reaction with polymerization or termination, such as ethylene oxide which, after termination, produces a hydroxyl group at the ends of the polymer. A heterotelequale polymer is one that has one type of functional group at one end of the molecule and another type of functional group at the other end of the molecule. Anionic polymerization is also a convenient way of making heteropolymeric polymer. For example, polymers having ethylenic unsaturation can be manufactured in the molecule, via the polymerization of a diene monomer, and also having a terminal functional group, via a coronation reaction, for example a hydroxyl group, via coronation with oxide of ethylene. The ethylenic unsaturation may be useful, as such, in the heterotelecholic polymer, for example by thermal curing with sulfur or melamine, or it may be used for further functionalization reactions, such as conversion to epoxide. Anionic polymerizations are usually carried out in solution. When polymerizing to a high molecular weight, the polymer will generally recover as a solid, such as lumps, a powder, trocizcos or the like. When polymerized at a low molecular weight, it can be recovered as a liquid, such as the present invention. In general, when using anionic techniques in solution, copolymers of conjugated diolefins, optionally with vinylaromatic hydrocarbons, are prepared by contacting the monomer or monomers to be polymerized, simultaneously or sequentially, with an anionic polymerization initiator, such as group IA metals, their alkyls, amides, silanolates, naphthalides, diphenyls or anti-racer derivatives. It is preferred to use an organic compound of alkali metal (such as lithium, sodium or potassium) in a suitable solvent, at a temperature in the range of from about -150 ° C to about 300 ° C, preferably at a temperature which is in the range from about 0 ° C to about 100 ° C. Particularly effective anionic polymerization initiators are organic lithium compounds, having the general formula: RÜn wherein R is an aliphatic, cycloaliphatic, aromatic or aromatic hydrocarbon radical substituted with alkyl, having from 1 to about 20 carbon atoms and preferably from 3 to 5 carbon atoms, and n is an integer from 1 to 4. Conjugated diolefins which can be anionically polymerized, include those conjugated diolefins containing from about 4 to about 24 carbon atoms, such as 1,3-butadiene, isoprene, piperylene, methopentadiene, phenyl-butadiene, 3,4-dimime 1-, 1-, 3-hexadiene, 4,5-diethyl-1,3-octadiene and the like. Isoprene and butadiene are the preferred conjugated diene monomers for use in the present invention, because of their low cost and easy availability. Alkenyl (vinyl) aromatic hydrocarbons, which may be copolymerized, include vinylaryl compounds such as styrene, various alkyl substituted styrenes, alkyloxy substituted styrenes, vinylnaphthalene, alkyl substituted alkylnanes and the like. Preferred hydroxyl groups of the telechelic and heterotelequale polymers of the present invention will react with the isocyanate-based curing agent at ambient conditions to form a pressure-sensitive sealant adhesive composition while the other type of functionality will cure only by baking at a temperature of at least 100 ° C, to make a structural adhesive or sealant composition. The telechelic polymer provides strength to the composition, of adhesive or sealant, sensitive to pressure, cured at room temperature. If the telechelic polymer is a diol or a polyol, there are many types that can be used. Polydienediols and polydiene polyols, as well as their saturated analogues, can be used, as can polyether, polyester, and acrylic polyols. The preferred telechelic polymers for use in the present invention are the conjugated diene diols and polyols, preferably the hydrogenated diols and polyols of conjugated dienes. There are many types of heterotelequic polymers that can be used herein. As stated above, one end of the heterotelequic polymer will have the same functional group as the telechelic polymer. The other end will have a different type of functional group which does not react with its crosslinker, under the same conditions used to crosslink the telechelic polymer. Heterotelechlic polymers can include those wherein functional, protected, and / or functional, protected, coronation agents are included. The heterotelequélicos polymers can also be manufactured by functionalization reactions, in telechelic polymers. In a more preferred embodiment of this invention, the polymer system is a combination of telechelic and heterotelequic polymers, with hydroxy functionality, wherein the other functionality of the heterotelechlic polymer is an olefinic epoxide. The curing system is an isocyanate for curing at room temperature and a melamine resin for curing by baking, after the adhesive has been applied. However, this invention is not restricted to these chemical compounds. The following are some examples of other suitable telechelic and heterotelequinic polymers. If the telechelic polymer has hydroxyl functionality, the heterotelechlic polymer will also have a hydroxyl group and also another type of functional group such as C = C unsaturation (for sulfur curing or curing with melamine), acrylic unsaturation (for radical curing) free, via peroxide or radiation), olefin converted to epoxide (for cationic curing via a blocked Lewis acid or for radiation curing or curing with melamine), or glycidyl ether epoxide (for curing with acid or anhydride , or catalytic curing). If the telechelic polymer has acrylic unsaturation (for curing by free radicals at room temperature, via peroxide or radiation), the heterotelequale polymer will also have an acrylic group and another functional group such as a hydroxy functionality (for curing with melamine or blocked isocyanate), olefinic unsaturation, glycidyl ether epoxide, or epoxide converted to epoxide functionality. If the telechelic polymer has glycidyl ether functionality (for curing at room temperature, with aliphatic amines), the heterotelechlic polymer will have glycidyl ether epoxy functionality, and another functional group such as olefinic unsaturation, epoxide converted olefin, or hydroxy functionality. There are many other combinations for functional groups and for curing systems and in this way there are many possibilities for dual curing systems. The polydiene, telechelic polymers are preferably synthesized by anionic polymerization of conjugated diene hydrocarbon monomers, such as butadiene or isoprene, with lithium initiators. The steps of the process are known as described in U.S. Patent Nos. 4,039,593, Reissued Patent No. 27,145, and No. 5, 376, 745. Polymerization begins when a dilithium or polylithium initiator forms a skeleton or structure latent polymer in each lithium site. Typical structures of latent polymers of dilithium, which contain conjugated diene hydrocarbons are: Li-B-X-B-Li Li-B-A-X-A-B-Li Li-A-B-A-X-A-B-A-Li wherein B represents polymerized units of one or more conjugated diene hydrocarbons such as butadiene or isoprene, A represents polymerized units of one or more compounds of conjugated dienes and / or vinylaromatics, such as styrene, and X is the residue of the diinitiator , such as the initiator formed by the reaction of diisopropenylbenzene with two moles of sec-butyllithium. B can also be a copolymer of a conjugated diene and a vinylaromatic compound. The anionic polymerization is carried out in solution in an organic solvent, typically a hydrocarbon such as hexane, cyclohexane or benzene, although polar solvents such as tetrahydrofuran can also be used. When the conjugated diene is 1, 3-butadiene and when the resulting polymer will be hydrogenated, the anionic polymerization of butadiene in a solvent similar to ciciohexano hydrocarbons is typically controlled with structure modifiers such as diethyl ether or Glima (1,2-diethoxyethane) to obtain the desired amount of 1,2 addition. As described in Reissue Patent No. 27,145, the level of 1,2-addition of butadiene in the polymer or copolymer can greatly affect the viscosity and elastomeric properties after hydrogenation. The optimum balance between a low viscosity and a high solubility, in a hydrogenated polybutadiene polymer, occurs at a ratio of 60/40 of 1,4-butadiene / 1,2-butadiene. This butadiene microstructure is achieved during the polymerization at 50 ° C in cyclohexane to obtain approximately 6% by volume of diethyl ether, or approximately 100 ppm of glyme. This is not the case when isoprene is the monomer used to make the hydrogenated polydiene polymer and therefore the polymerization can be carried out in a pure hydrocarbon solvent, without modifier. The hydrogenated polymers exhibit improved thermal stability and weather resistance in the final adhesive or sealant. After completion of the polymerization of the monomers, the hydroxyl groups are added capping the ends of the living polymer chain with a crowning agent, typically ethylene oxide, and terminating with a proton donor, typically methanol.

A saturated dihydroxypolidiene polymer can also be made using a monolithium initiator containing a hydroxyl group that has been blocked as the silyl ether. Details of the polymerization process can be found in U.S. Patent No. 5,376,745. A suitable initiator is the hydroxypropyl ether in which the hydroxyl group is blocked as the ter-butyl-dimethylsilyl ether. This monolithium initiator can be used to polymerize isoprene or butadiene, with or without styrene, in hydrocarbon or polar solvent. The molar ratio of initiator to monomer determines the molecular weight of the polymer. The latent polymer is then capped with one mole of ethylene oxide and terminated with one mole of ethanol, to produce the monohydroxy polydiene polymer. The silyl ether is then removed by acid catalyzed decomposition, in the presence of water, to produce the desired dihydroxypolidiene polymer. Polyhydroxylated polydiene polymers can be obtained using similar technology. The multifunctional lithium initiators can be prepared from the reaction of sec-butyllithium with di-isopropylbenzene, in a molar ratio of at least 2: 1. These multilite initiators can then be used to polymerize butadiene in solvent. The latent polymers should then be capped with ethylene oxide and terminated with methanol to give the polydiene polyhydroxy side polymer. Alternatively, the protected monolithium initiator can be used to polymerize butadiene or isoprene. The latent polymer can be coupled with a coupling agent, multifunctional, and the blocking agent should be removed later, to regenerate the hydroxyl group. A trifunctional coupling agent, such as methyl trimethoxy, would produce a trihydroxy polydiene polymer. A coupling agent, tetrafunctional, similar to silicon tetrachloride, would produce a tetrahydroxy polydiene polymer. A coupling agent, of propagation, similar to divinylbenzene would reduce a multihydroxy polydiene polymer having up to 20 hydroxyl groups per polydiene polymer. The monohydroxylated, heterotelequale polydiene polymers are also synthesized by the anionic polymerization of conjugated diene hydrocarbons, such as butadiene or isoprene, with lithium initiators. The steps of the process are the same as for the telechelic, multifunctional polymers, except that the polymerization begins with a monolithium initiator instead of a mu ti t 1 i t io initiator. The polydiene polymers, hydroxylates, of this invention will have equivalent hydroxyl weights that are between 500 and 20,000, preferably between 1,000 and 15,000, and most preferably between 2,000 and 10,000. Thus, for the monohydroxy polydiene polymers, the maximum, suitable molecular weights will be between 500 and 20,000. Below the lower molecular weight range, the costs become prohibitively high due to the high cost of the polymerization initiator. Above the highest molecular weight range, the viscosity becomes somewhat high, making mixing and application of the adhesive more difficult and, at those high values of hydroxyl equivalent weights, it becomes difficult to achieve the desired polyurethane chemistry. Preferably, the telechelic polymer is a diol or polyol of at least one conjugated diene of the formula HO-A-S, -BOH (HO-A-Sz-B) n-Y wherein A and B are polymeric blocks which may be homopolymeric blocks of conjugated diolefin monomers, copolymeric blocks of conjugated diolefins, or copolymer blocks of diolefin monomers and monomeric monocarbon hydrocarbon monomers, S is a block of the vinylaromatic hydrocarbon, Y is a coupling agent, z is 0 or 1, and n is an integer from 1 to 20. The heterotelechlic polymer is preferably a monohydroxy polydiene side, converted to epoxide, which is comprised of at least two ethylenically unsaturated, polymerizable monomers, wherein at least one is a diene monomer, which produces a suitable unsaturation for conversion to epoxide. Heterotelequic polymers, hydroxylates, are the most preferred block copolymers of at least two conjugated dienes, preferably isoprene and butadiene, and optionally, a vinylaromatic hydrocarbon wherein a hydroxyl group is attached to one end of the polymer molecule . These polymers can be hydrogenated or non-hydrogenated. The epoxide-converted polydiene monohydroxy side polymer preferred for use in accordance with the present invention has the structural formula I) (HO) X-A-Sz-B- (OH! wherein A and B are polymer blocks which may be homopolymer blocks of conjugated diolefin monomers, copolymer blocks of conjugated diolefin monomers, or copolymer blocks of diolefin monomers and monoalkenyl aromatic hydrocarbon monomers. These polymers can contain up to 60% by weight of at least one vinylaromatic hydrocarbon, preferably styrene.

Generally, it is preferred that blocks A have a higher concentration of highly substituted aliphatic double bonds than that of blocks B. Just as blocks A have a higher concentration of unsaturated sites, subsitiated, trisubstituted, or tetrasubs ti tuida (double aliphatic bonds) per unit mass of the block, that which B blocks have. This produces a polymer where the conversion to epoxide, easier, occurs in blocks A. Blocks A have a weight molecular from 100 to 6,000, preferably from 500 to 4,000, and most preferably from 1,000 to 3,000, and B blocks have a molecular weight of 1,000 to 15,000, preferably 2,000 to 10,000, and most preferably 3,000 to 6,000. S is a vinylaromatic hydrocarbon block that can have a molecular weight of 100 to 10,000. x and y are 0 or 1. Any of x or y can be 1, but only one at a time can be 1. z is 0 or 1. Any of the blocks A or B can be crowned with a polymer miniblock, with a molecular weight of 50 to 1,000, of a different composition, to compensate for any initiation, tapering due to unfavorable speeds of copolymerization, or difficulty in coronation. These polymers are converted to epoxide, in such a way that they contain from 0.2 to 7.0 ml 1 liter valent (meq) of epoxy groups per gram of polymer. The most highly preferred polymers, for use herein, are the diblock polymers, which fall within the scope of formula (I) above. The overall molecular weight of these diblocks can vary from 1,500 to 15,000, preferably from 3,000 to 7,000. Any of the blocks found in the diblock may contain some randomly polymerized vinylaromatic hydrocarbon, as described above. For example, where I represents isoprene, B represents butadiene, S represents styrene, and a diagonal line (/) represents a random, copolymer block, and the diblocks may have the following structures: IB-OH IB / S-OH I / SB-OH II / B-OH OB / IB / S-OH BB / S-OH I-EB-OH I-EB / S-OH OR IS / EB-OH I / S-EB-OH HO-IS / B HO-IS / EB wherein EB is hydrogenated butadiene, -EB / S-OH means that the hydroxyl source is bound to a styrene polymer and S / EB-OH means that the hydroxyl source is attached to a hydrogenated butadiene polymer. This last case, S / EB-OH requires the coronation of the S / EB block of "random copolymer", with an EB mini-block to compensate the taper tendency of the styrene, before the coronation with the ethylene oxide. These diblocks are advantageous because they exhibit a lower viscosity and are easier to manufacture than the corresponding triblock polymers. It is preferred that the hydroxyl be attached to the butadiene block, because the conversion to epoxide is carried out more favorably with isoprene and there will be a separation between the functionalities found in the polymer. However, the hydroxyl block may also be attached to the isoprene block if desired. This produces a molecule more similar to a surfactant, with less capacity to bear load. The isoprene blocks can also be hydrogenated. Also preferred for use herein are certain triblock copolymers. These triblocks usually include a randomly copolymerized styrene or styrene block to increase the glass transition temperature of the polymers, compatibility with polar materials, strength or strength, and viscosity at room temperature. These tribloques include the following specific structures: I-EB / S-EB-OH I-B / S-B-OH I-S-EB-OH I-S-B-OH O I-I / S-I-OH I-S-I-OH B-S-B-OH B-B / S-B-OH or I-B / S-I-OH I-EB / S-I-OH or I-B-S-OH I-EB-S-OH HO-I-EB-S The last group of polymers, specified in the last line above, where the styrene block is external is represented by the formula (II) (HO) X-A-B-S- (OH) where A, B, S, x, e and are as described above. These polymers and the other triblocks shown above are particularly advantageous for introducing blocks of epoxy functionality into the polymers at multiple sites. Hydroxylated polydienes, hetero-telechelic, synthesized by anionic polymerization, will also have olefinic unsaturation. Although these polymers can be useful as such, the olefinic unsaturation can also be converted to epoxide. The conversion to epoxide of the base polymer can be effected by reaction with organic peracids which can be preformed or formed in situ. Suitable preformed peracids include peracetic and perbenzoic acids. The in situ formation can be carried out using hydrogen peroxide, and a low molecular weight fatty acid, such as formic acid. Alternatively, hydrogen peroxide in the presence of acetic acid or acetic anhydride and a cation exchange resin will form a peracid. The cation exchange resin can optionally be replaced by a strong acid such as sulfuric acid or p-toluenesulfonic acid. The conversion reaction to epoxide can be carried out directly in the polymerization cement (polymer solution in which the polymer was polymerized) or, alternatively, the polymer can be redissolved in an inert solvent. These methods are described in greater detail in U.S. Patent Nos. 5,229,464 and 5,247,026. The molecular weights of the linear polymers or of the non-assembled linear segments of polymers such as the arms of monoblocks, diblocks, triblocks, etc., of star polymers, before coupling, are conveniently measured by Gel Permeation Chromatography ( GPC for its acronym in English), where the GPC system has been calibrated appropriately. For anionically polymerized linear polymers, the polymer is essentially monodisperse (with a weight average molecular weight / number average molecular weight ratio approaching unity), and it is both convenient and adequately descriptive to report the molecular weight " maximum "of the narrow distribution of molecular weights, observed. Usually, the maximum value is between the average molecular weight in number and the molecular weight in weight. The maximum molecular weight is the molecular weight of the main species found in the chromatograph. For idispersed polymers, the weight average molecular weight should be calculated from the chromatograph and used. In GPC columns, commonly used iodine-divinium benzene gels or silica gels are used, and these are excellent materials. Tetrahydrofuran is an excellent solvent for polymers of the type described herein. A refractive index detector may be used. The measurement of the true molecular weight of a coupled star polymer is not as direct or as easy as using GPC. This is because the star-shaped molecules do not separate and do not elute through the GPC columns, packed, in the same way as the linear polymers used for calibration. Hence, the arrival time of a refractive index or ultraviolet detector is not a good indicator of molecular weight. A good method to be used with star polymers is to measure the weight average molecular weight through light scattering techniques. The sample is dissolved in a suitable solvent at a concentration of less than 1.0 gram of sample per 100 ml of the solvent, and filtered using a syringe and porous membrane filters with a pore size less than 0.5 micron., directly in the cell for the dispersion of light. The light scattering measurements are made as a function of the dispersion angle, the polymer concentration and the polymer size, using standard procedures. The differential refractive index (PRI) of the sample is measured at the same wavelength and in the same solvent used for light scattering. Some relevant references are: 1. Liquid Chromatography with Exclusion of Sizes, Modern, M.W. Yau, J.J. Kirkland D.D. Bly, John Wiley and Sons, New York, New York, 1979. 2. Luminous Dispersion of Solutions Polymeric, M.B. Huglin, ed., Academic Press, New York, New York, 1972. 3. W. K. Kai and A. J. Javlik, Applied Optics, 12, 541 (1973). 4. M. L. McConnell, North American Laboratory, 63, May, 1978.

If desired, these block copolymers can be partially hydrogenated. The hydrogenation can be carried out selectively as described in Reissued US Patent No. 27,145. The hydrogenation of these polymers and copolymers can be carried out, through a variety of well-established processes including hydrogenation in the presence of catalysts such as Raney Nickel, noble metals such as platinum and the like, catalysts and metal transition, solubles, and titanium catalysts as in U.S. Patent No. 5,039,755. A particularly preferred catalyst is a mixture of nickel 2-ethylohexanoate and triethylaluminium. The polymers can have different diene blocks and these diene blocks can be selectively hydrogenated as described in U.S. Patent No. 5,229,464. The polydiene, telechelic polymers of this invention are preferably hydrogenated, such that at least 90%, preferably at least 95%, of the carbon-to-carbon double bonds are saturated. It is preferred that the diene polymers, heterotelequale, be partially unsaturated, so that the carbon-to-carbon double bonds can be used as such or can be used for further functionalization in order to make the epoxide-converted polymers of this invention. . The level of unsaturation in the heterotelequélicos polymers should be from 0.2 to 7.5 meq of double bonds per gram of polymer. The amount of telechelic polymer used in the polymer portion of the adhesive or sealant composition may vary from 95 to 15% by weight. If less than 15% is used, the pressure sensitive adhesive will not have enough strength and if it is used more than 95% there will be very little heterotelequin polymer to cure, and the cohesive force will increase. The amount of the dual cure system will depend on the type of functionality in the heterotelequic polymer and the particular curing system used. Normally, however, the telechelic and heterotelequic polymers, with hydroxyl functionality, will be cured with a stoichiometric amount of isocyanate. If the olefinic unsaturation is the other functionality that is found in the heterotelequic polymer, then a crosslinking system based on sulfur, in an amount of 0.5 to 6% by weight, will be used. If an olefin converted to epoxide is the other functionality that is found in the heterotelequic polymer, then an amine resin crosslinking will be used, in an amount of 2 to 20% by weight. The polyisocyanate used in this invention may be an aliphatic or aromatic polyisocyanate, or a mixture of the two. The aliphatic polyisocyanates are those that are generally preferred as they will provide sealants and adhesives that have a lighter color and better durability than the aromatic polyisocyanates. Since the hydroxylated, saturated, telechelic and heterotelequinic polydiene polymers can have functionalities as small as 1 or 2 hydroxyl groups per molecule, it is necessary that the isocyanate has a functionality greater than 2, to ensure that the composition of adhesive or sealant , of polyurethane, is crosslinked into a cohesive mass. Typically, the polyisocyanate will have a functionality of 3 or more isocyanate functional groups (NCO) per molecule. However, it is possible to use difunctional or monofunctional isocyanates, in combination with polyfunctional isocyanates. The dual curing system preferably contains an isocyanate having an equivalent weight between 50 and 500. Examples of polyfunctional isocyanates, aromatic, suitable, are the 1,4-benzene triisocyanate, the polymethylene polyphenyl isocyanate (MONDUR MR ex MILES), the toluene diisocyanate adduct with trimethylol propane (MODUR CB-60 ex MILES). Examples of suitable polyfunctional, aliphatic isocyanates are the isocyanurate or isophorone diisocyanate (DESMODUR Z-4370 ex MILES) and the isocyanurate of hexane diisocyanate (DESMODUR N-3390 ex MILES). It has been found that DESMODUR Z-4370 is a particularly effective triisocyanate for this invention because it has excellent compatibility with the hydroxylated, saturated polydiene polymers of this invention. It provides adhesives and sealants, colorless, clear, with an adhesive and detachment, excellent, and that will also have an excellent durability, even under exposure to sunlight. (MONDUR, MILES and DESMODUR are trademarks).

Although isocyanates having 3 more NCO groups per molecule will be the main component of the polyisocyanate curing agent, small amounts of isocyanates and monoisocyanates may also be used. Suitable diisocyanates are toluene diisocyanate, di-phenylenediane diisocyanate, isophorone diisocyanate, dicyclohexy-limetane diisocyanate and hexane diisocyanate. Suitable monoisocyanates are toluene diisocyanate, phenyl isocyanate and cyclohexyl isocyanate. Polyisocyanate adducts can also be used in this invention. These are typically manufactured by crowning a diol or triol of polypropylene oxide or a diol or triol of polycaprolactone, with a diisocyanate. When the heterotelequin polymer has olefinic epoxy functionality, the crosslinking agents that are useful in the present invention are the amino resins. For purposes of this invention, an amino resin is a resin made by the reaction of a material possessing NH groups, with a carbonyl compound, and an alcohol. The material containing NH groups is commonly urea, melamine, benzoguanamine, glycoluril, cyclic ureas, diureas, guanidines, urethanes, cyanamides, etc. The most common carbonyl component is formaldehyde and other carbonyl compounds include higher aldehydes and ketones. The most commonly used alcohols are methanol, ethanol, and butanol. Other alcohols include propanol, hexanol, etc. American Cyanamid (renamed CYTEC) sells a variety of these amino resins, as do other manufacturers. The American Cyanamid literature describes three classes or "types" of amine resins that offer the a CMjOß or T N CHjOH or - < CHj? T Type 1 CHjOH / t * e < * CH20H Type 2 Type 3 wherein Y is the material possessing the NH groups, the carbonyl source was formaldehyde and R is the alkyl group of the alcohol used for the alkylation. Although this type of description presents amino resins as a monomeric material of a single pure type, commercial resins exist as mixtures of monomers, dimers, trimers, etc., and any given resin may have some characteristic of the other types. Dimers, trimers, etc., also contain methylene or ether sources. In general, amine resins of type 1 are preferred in the present invention. The amine resin must be compatible with both the telechelic polymer and the heterotelequic polymer. A compatible amine resin is defined as one that provides a stable mixture in its phase, with the polymers, at the desired concentration and at the temperature to which the compositions will be mixed and applied. The dual curing system preferably contains an amine resin having an equivalent weight between 50 and 500. For example, the following amine type 1 resins can be used to achieve the purpose of the present invention: CYMEL 1156 - a melamine resin - formaldehyde wherein R is C4H9, CYMEL 1170 - a glycoluril-formaldehyde resin wherein R is C4H9, CYMEL 1141 - a carboxyl-modified amino resin, wherein R is a mixture of CH3 and I-C4H9, and BEETLE 80 - a urea-formaldehyde resin where R is C4H9. All these products are manufactured by American Cyanamid Company and 50 Years of Aminic Resins for Coatings are described in their publication, edited and written by Albert J. Kirsch, published in 1986 together with other amino resins useful in the present invention. (CYMEL and BEETLE are trademarks). CYMEL 1170 is the following glycoluril-formaldehyde resin, where R is C4H9: BEETLE 80 is a urea-formaldehyde resin, where R is C4H9 and whose ideal monomeric structure is represented by: The adhesive and sealant compositions of this invention may consist only of the telechelic and heterotelequale polymers, with the reticulators of the dual cure system. However, it may be necessary for a formulator to combine a variety of ingredients together with the polymers of the present invention, to obtain products that contain the right combination of properties, (such as adhesion, cohesion, durability, low cost, etc.) for particular applications. Although a suitable formulation could only contain the polymers and curing agents, in most applications of adhesives and sealants, suitable formulations will also contain various combinations of resins, plasticizers, fillers, solvents, stabilizers and other ingredients such as asphalt. The following are some typical examples of formulation ingredients, for adhesives and sealants. To obtain a high adhesiveness in the pressure sensitive adhesive, it may be necessary to add a viscosifying or adhesion promoting resin, which is compatible with the polymers. A common resin, which provides adhesiveness, is a diene-olefin copolymer of piperylene and 2-me t i 1-2-but ene, which has a softening point of about 95 ° C. This resin is commercially available under the trade name WINGTACK 95 (trademark) and is prepared by the cationic polymerization of 60% piperylene, 10% isoprene, 5% cyclo-pentadiene, 15% 2-methylamino- 2-butene and approximately 10% dimer, as described in US Patent No. 3,577,398. Other resins that provide adhesiveness can also be used, wherein the resinous copolymer comprises from 20 to 80% by weight of piperylene and from 20 to 80% by weight of 2-me t i 1-2-butene. The resins usually have softening points, in ring and ball, as determined by the method E 28 of ASTM, between approximately 80 ° C and 115 ° C. Aromatic resins can also be employed as agents that provide adhesiveness, provided that they are compatible with the particular polymers used in the formulation. Normally these resins should also have softening points, in ring and ball, that are between approximately 80 ° C and 115 ° C, although mixtures of aromatic resins with high and low softening points can also be used. Useful resins include coumaron-indene resins, polystyrene resins, vinyl toluene-al-methyl-tertiary copolymers, and polyindene resins. Other adhesion-promoting resins, which are also useful in the compositions of this invention, include hydrogenated rosins, rosin esters, pol terpenes, terpenephenol resins and polymerized mixed olefins, resins with lower softening points and liquid resins. An example of a liquid resin is the ADTAC LV resin (trademark) of HERCULES. To obtain color stability and thermooxidative stability it is preferred that the adhesive-providing resin be a saturated resin, for example a hydrogenated dicyclopentadiene resin, such as the ESCOREZ 5000 series resin manufactured by EXXON, or a resin of polystyrene or polyalphame tiles t irene, hydrogenated, such as REGALREZ, resin that is manufactured by HERCULES.

(ESCOREZ, REGALREZ, EXXON and HERCULES are trademarks). The amount of adhesion-promoting resin employed varies from 0 to 400 parts by weight per 100 parts of polymer (pcpp), preferably between 20 to 350 pcpp, and most preferably from 20 to 150 pcpp. The selection of the agent that provides particular adhesiveness is, to a large extent, dependent on the specific polymers employed in the composition of the adhesive. A composition of the present invention may contain plasticizers, such as rubber extender plasticizers, or blend oils, or organic or inorganic pigments, and colorants. Oils for blends, of rubber, are well known in the art and include oils of high content of saturated compound and oils with high content of aromatic compounds. Preferred plasticizers are highly saturated oils, for example TUFFLO 6056 and 6204 oil manufactured by ARCO and process oil, for example SHELLFLEX 371 oil manufactured by SHELL. The amounts of oil for mixtures, of the rubber, used in the composition of the invention, can vary from 0 to 500 pcpp, preferably between 0 and 100 pcpp, and most preferably between 0 and 60 pcpp. (TUFFLO, ARCO, SHELLFLEX, and SELL are trademarks). Various types of fillers and pigments can be included in the formulation. This is especially true for adhesives or sealants, for exteriors, where filler materials are added not only to create the desired appearance but also to improve the performance of adhesives and sealants, as well as their resistance to weathering. A wide variety of fillers can be used. Suitable fillers include calcium carbonate, clays, talcs, silica, zinc oxide, titanium dioxide, and the like. The amount of the filler material is usually in the range of 0 to 80 pcpp, depending on the type of filler material used, and the application for which the adhesive or sealant is intended to be used. A particularly preferred filler material is titanium dioxide. Stabilizers known in the art can also be incorporated into the composition. This may be for protection during the life of the article, against, for example, oxygen, ozone and ultraviolet radiation, or for protection against degradation during mixing, application or curing. Typical stabilizers are antioxidants, usually hindered phenolic compounds, and UV inhibitors, usually benzophenone or benzotriazole compounds, or light stabilizers based on hindered amine. The amount of stabilizer used depends highly on the application for which the composition is intended to be used, but generally, the stabilizers will be used in an amount of 0.1 to 10 pcpp. All adhesive and sealant compositions, based on this invention, will contain some combination of various formulation ingredients, which are described herein. No definite rules can be offered about what ingredients will be used. The experienced formulator will select the particular types of ingredients and adjust their concentrations to give exactly the combination of properties needed in the composition for any specific application of the adhesive or sealant. Then, in addition to the telechelic polymer, heterotelequic polymer and the two systems of curing agents, the formulator will choose to use or not use the different resins, fillers and pigments, plasticizers, oligomers, stabilizers and solvents. The key to the concept of the present invention is to manufacture a pressure sensitive adhesive or sealant that can be further cured after it is applied, causing it to behave as a structural adhesive or sealant. The adhesive or seal is based on a telechelic polymer blend, such as the preferred hydrogenated diol, with a heterotelequic polymer, such as the epoxide-converted monohydroxy diene polymer, preferred, and a dual curing system, including, for example, an isocyanate and an amino resin. A pressure sensitive adhesive composition (or pressure sensitive sealant composition) is formed which can be applied to a substrate and which will immediately adhere thereto. Then, when the assembly is baked, the composition is cured by curing the epoxy groups, because of the aminic resin, further increasing the cohesive strength and modulus of the adhesive or sealant composition, and causing them to work in more like a structural adhesive than a pressure-sensitive adhesive. A specific use for these compositions is to manufacture a free film that is a pressure sensitive adhesive between two layers of paper that allows peeling. This free film is then used to adhere automobile parts, such as reinforcements of hoods and doors, with enough force to join them in one position, until the body or structure is baked or heated. Upon baking, the adhesive cures additionally, providing a structural or at least semi-structural bond, which permanently holds the parts in a certain position. This use has the additional benefit that the free film, of the pressure sensitive adhesive, between two layers of release paper, can be punched to an exact size and shape, necessary for the particular application.

EXAMPLES In the following examples, the telechelic polymer (Polymer A) is a hydrogenated polybutadiene diol (HO-EB-OH) with a molecular weight (MW) of 3,500. Three heterotelequélicos polymers were used. All three had a molecular weight of 6,000. Polymer C is a polyisoprene block with 2,000-polystyrene MW with MW of 2,500 / polybutadiene random copolymer block with MW of 1,500, -OH (IS / EB-OH) in which the polybutadiene has been selectively hydrogenated and the Polyisoprene has been converted to epoxide to a level of 1.5 meq epoxy / g. Polymer D is a block of polyisoprene with MW of 2,000 - block of polybutadiene with MW of 4,000 -OH (I-EB-OH) in which the polybutadiene has been selectively hydrogenated and the polyisoprene has been converted to epoxide up to 1.5 meq / g. Polymer E is the same polymer D except that isoprene has not been converted to epoxide, but retains 1.5 meq / g of double bonds. Polymer B is a non-heterotelequic polymer, used for comparative effects with heterotelequale polymers. It is a hydrogenated polybutadiene monol, with MW of 3,000 (EB-OH). HO-EB-OH was used with each of the four monools, with and without resin that provides adhesiveness, but curing its hydroxyl groups with a trifunctional isocyanate, DESMODUR Z-4370, to give a pressure sensitive adhesive (PSA) ) based on polyurethane, which also contained the melamine resin, CYMEL 1156. The intention was that this PSA could be used as any normal PSA to adhere two substrates, that would give an instantaneous bond under light pressure and have sufficient shear strength to hold the pieces together, under a modest load. Then, after the adhesive was put in place, the assembly had to be heated to perform the curing with melamine, of the epoxy groups, and to improve enough the shear strength or resistance, in such a way that the adhesive could support a high enough to perform as a structural adhesive. To analyze this approach, formulations 1 through 4 of the table were prepared using a diol / monol weight ratio of 35/65. To 80 parts by weight (ppp) of this diol / monol mixture were added 18 ppp of the butylated melamine resin, CYMEL 1156, and 2 ppi of dodecylbenzene ionic acid-based catalyst, CYCAT 600 (CYCAT 600 is a 70% by weight of acid in isopropyl alcohol), to catalyze the melamine / epoxy reaction, when the adhesive is baked or heated. (CYCAT is a trademark). This mixture was dissolved to a solids content of 64% by weight, in dry xylene, to give the hydroxyl side of the two component polyurethane. Immediately before casting films of the adhesives, DESMODUR Z-4370 was added with a stoichiometric ratio of NCO / OH, 1/1 (including the alcohol introduced with the CYCAT 600), together with 0.04% dibutyltin dilaurate catalyst ( DABCO T-12), to catalyze the isocyanate / hydroxyl reaction. These adhesive solutions were poured onto a 2540 x 10"m (1 mil) thick polyester film using a # 52 wire rod.The films were dried / cured for 5 days at room temperature before analysis. Formulations 1-4 did not contain resin that would provide adhesiveness Formulations 5-8 are the same as 1-4 except that they also contain adhesivity-providing resins, REGALREZ 1085, at the same concentration as the diol / monol. PSA standards, rolling ball adhesiveness, polyken probe adhesiveness, 180 ° detachment and clamping power were carried out on the adhesives after curing at room temperature This is the condition in which the adhesives would be found when used as pressure sensitive adhesives Test specimens for 180 ° detachment, clamping power and Shear Adhesion Failure Temperature (SAFT), for its acronym in English) were prepared and baked for 1 hour at 100 ° C. This is the condition in which the adhesives would be found when they were functioning as structural adhesives. The SAFT was not measured in adhesives cured at room temperature because these would probably cure as the test temperature increased. The SAFT was measured by a joint made with the component, from MYLAR to MYLAR, with dimensions of 2,540 x 10 - 2 x 2,540 x 10 - 2 m (1 in. X 1 in.), With a weight of 9,807 N (1 kg. ). The SAFT measures the temperature at which the assembly fails, under a load, by shear at the joint. Rolling Ball Adhesion (RBT) is the distance at which a steel ball rolls on the adhesive film, with a standard initial velocity (Test No. 6 of the Council for Pressure Sensitive Tapes) . Small numbers indicate an aggressive adhesiveness. Holding power (HP) is the time required to pull a standard area of 1.77 x 10 mx 1.77 x 10"2m (1/2 in. X 1/2 in.) Of tape, a test surface standard (steel, or paper Kraft) under a standard load of 19,614 N (2 kg), in shear with anti-peel at 2 ° (Method No. 7 of the Council of Pressure Sensitive Tapes). Long times indicate high adhesive strength. The 180 ° detachment was determined by Method No. 1 of the Council of Pressure Sensitive Tapes. Large numbers indicate great strength when a test tape is detached from a steel substrate. Adhesiveness in polyken probe (PPT) was determined by ASTM D-2979. High numbers of PPT indicate an aggressive adhesiveness. After the adhesives were dried and cured for 5 days at room temperature, the hydroxyl / isocyanate reaction had essentially come to an end. All the films were coherent and, when they were touched, no adhesive was transferred to the finger. The films were classified qualitatively with respect to their clarity and adhesion to the finger. The adhesives 2 and 6 were unique. They were a bit darker, showing that the C adhesive has poor compatibility with Polymer A, and has poor adhesion to the finger, probably reflecting the impact of the styrene content on Polymer C. All the other adhesives were fairly clear and generally had good adhesiveness The adhesives 1 and 5 are the control adhesives, without and with resin that provides adhesiveness, in which the monol (Polymer P) used has only one hydroxyl group and is not heterotelequale. After curing at room temperature, these adhesives have good adhesiveness and fail cohesively in the clamping and detachment tests. After baking, clamping power values are improved, the peel strength of the adhesive 5 is increased, and the failure mechanism in the peel test, in adhesive 1, becomes a failure, from cohesive to adhesive . However, the holding power and the SAFT of these two formulations, after baking, are much lower than those of other formulations. Adhesives 2 and 6 have poor adhesiveness and high holding power after curing at room temperature. Detachment and holding power do not change when baked. The high values of detachment, clamping power and SAFT, of the adhesive 6, are impressive. This suggests that if a higher than normal bonding pressure can be applied to manufacture the assembly or assembly to compensate for poor adhesiveness after curing at room temperature, the adhesive 6 can behave quite well as a structural adhesive, when bakes The adhesives 3 and 7 used Polymer D. This monol does not contain styrene in such a way that it must maintain a low vitreous transition temperature (Tg) and good adhesiveness in the cured adhesive at room temperature. The hydroxyl group not only has to participate in the urethane reaction, which cures at room temperature, but the epoxy groups have to participate in the reaction of the melamine, when baked. The results of the table show that, after curing at room temperature, the adhesive 3 has a slight adhesiveness, however it has excellent holding power. After baking, the adhesive 3 continues to have excellent holding power and has excellent SAFT. The failure mechanism in the peel test is adhesive failure, suggesting that the adhesive 3 has a substantial cohesive force after curing at room temperature, and that its cohesive force is increased upon baking, since its peel values decrease. The presence of adhesive-providing resin in the adhesive 7 improves the adhesiveness in polyken probe and the adhesiveness to the finger, in adhesive cured at room temperature. The adhesive cured when baked or heated has excellent clamping power and SAFT. The change in the failure mechanism, in the detachment test, from a partial cohesive failure, in the adhesive cured at room temperature, until a purely adhesive failure, in the cured adhesive with baking, suggests that the cohesive strength of the adhesive was increased as desired, when baked. Adhesives 4 and 8 performed well, probably because the unsaturation C = C participated in the curing reaction with melamine. Indeed, the results of the table show that the adhesive 4 after curing at room temperature, has good adhesiveness but low clamping power and fails cohesively in the stripping test. However, after baking, it has excellent clamping power and SAFT, and the failure mechanism becomes adhesive in the peel tests. These results suggest a clear increase in cohesive strength at baking. The adhesive 8, which contains resin that provides adhesiveness, has an even greater adhesiveness in polyken probe, than the adhesive 4. It also shows an increase in the holding power and in the peel strength, when baked, again suggesting an increase in the cohesive force.

Table 1 Table 1 (Continued) Table 1 (continued) (e a adhesive failure c cohesive failure 10 fifteen It is noted that in relation to this date, the best method known by the applicant to carry out the aforementioned invention, is the conventional one for the manufacture of the objects to which it relates. Having described the invention as an antecedent, property is claimed as contained in the following:

Claims (10)

1. Compositions of adhesives and sealants, structural, sensitive to pressure, characterized in that they comprise: (a) a polymer system comprising 95 to 15% by weight of a telechelic polymer and from 5 to 85% by weight of a heterotelequic polymer, in where at least one of the functionalities found in the heterotelechlic polymer is the same as the functionality found in the telechelic polymer, and (b) a dual curing system, wherein an element of the curing system cures the polymer telechelic to conditions close to environmental, so that a pressure-sensitive adhesive or sealant is formed, and the other element cures the heterotelequélico polymer, when baked at least at 100 ° C, to form a composition of adhesive or sealant , structural.

2. The compositions according to claim 1, characterized in that the telechelic and heterotelechlic polymers contain hydroxyl functionality, and the other functionality that is found in the heterotelecholic polymer is selected from the group consisting of olefinic epoxy groups, glycidyl ether epoxy groups, unsaturation C = C, and acrylic unsaturation.

3. The compositions according to claims 1 and 2, characterized in that the telechelic polymer is a diol or polyol of at least one conjugated diene of the formula HO-A-S, -B-OH or (HO-A-Sz-B) n-Y wherein A and B are polymeric blocks which can be homopolymer blocks of conjugated diolefin monomers, copolymer blocks of conjugated diolefins, or copolymer blocks of diolefin monomers and monoalkenylaromatic hydrocarbon monomers, S is a vinylaromatic hydrocarbon block, and is a coupling agent, x and y are 0 or 1, and any of x or must be 1 but only one at a time can be 1, z is 0 or 1 and n is an integer from 1 to 20.

4. The compositions according to claims 1 and 2, characterized in that the heterotelechlic polymer is a monohydroxy diene polymer, converted to epoxide, of the formulas (HO) -AS -B (OH) and or (HO) -AB- S (OH) and where A, B, S ,, X z XX, Y, Z are as defined above.

5. The compositions according to claims 1 to 4, characterized in that the dual curing system is comprised of an isocyanate having an equivalent weight that is between 50 and 500 and an amino resin having an equivalent weight that is found between 50 and 500.

6. The compositions according to claim 1, characterized in that the polymer system comprises a telechelic polymer containing acrylic unsaturation and a heterotelechlic polymer containing acrylic unsaturation and another functionality selected from the group consisting of olefinic unsaturation, olefinic epoxy groups, ether epoxy groups glycidyl, and hydroxy groups.

7. The compositions according to claim 1, characterized in that the polymer system comprises a telechelic polymer containing glycidyl ether epoxy functionality and a heterotelechlic polymer containing glycidyl ether epoxy functionality and another functionality selected from the group consisting of olefinic unsaturation, acrylic unsaturation , olefinic epoxy groups and hydroxyl groups.

8. The compositions according to claims 1 to 7, characterized in that the dual curing system is comprised of isocyanate having an equivalent weight that is between 50 and 500 and an amino resin having an equivalent weight that is between 50 and 500.

9. An adhesive characterized in that it comprises a cured or hardened composition according to claims 1 to 8.

10. A sealant, characterized in that it comprises a cured or hardened composition, in accordance with claims 1 to 8. SUMMARY OF THE INVENTION The present invention relates to compositions for adhesives and sealants, structural, pressure sensitive, comprising: (a) a system comprising 95 to 15% by weight of a telechelic polymer and 5 to 85% by weight of a heterotelequélico polymer, where at least one of the functionalities found in them is the same as the functionality found in the telechelic polymer, and (b) a dual curing system where an element of the curing system, cure the telechelic polymer at a temperature close to room temperature, such that a pressure-sensitive adhesive or sealant is formed, and the other element cures the telechelic polymer, upon baking at least at 100 ° C, to form a composition of adhesive or sealant, structural. In a preferred embodiment, the polymer system is comprised of a hydroxyl-functional, telechelic, diol or polyol polymer, and the heterotelechlic polymer is a monohydroxy polydiene polymer that also has olefin functionality, converted to epoxide. The dual curing system is preferably comprised of an isocyanate-based curing agent to cure the hydroxyl groups at room temperature to form a pressure sensitive adhesive or sealant and an amino resin to cure the epoxy functionality. , when baked, and form a structural adhesive or sealant.