MXPA97010193A - Solvent-free process for manufacturing adhesives and sealants curable with ultraviolet light apparatus of diohe polymers monohidroxiladosepixida - Google Patents

Abstract

The present invention relates to a solvent-free process for producing UV curable adhesive composition, comprising an epoxidized, monohydroxylated polydiene polymer, comprised of at least two polymerizable ethylenically unsaturated hydrocarbon monomers, wherein at least one is a diene monomer which produces unsaturation suitable for the epoxidation, and wherein the polymer contains from 0.1 to 7.0 milliequivalents of epoxy per gram of polymer, a monohydrogen of low molecular weight polydiene, an insoluble photoinitiator, and a resin that provides tackiness which is incompatible with the photoinitiator, the process is characterized in that it comprises predispersing the photoinitiator in the monool or the polymer or a mixture of the two and then adding the resin that provides stickiness or adhesion to the predispersion

Description

SOLVENT-FREE PROCESS FOR MANUFACTURING CURRENT ADHESIVES AND SEALANTS WITH ULTRAVIOLET LIGHT, FROM EPOXY MONOHIDROXYLED DIAMETER POLYMERS FIELD OF THE INVENTION This invention relates to a new process for manufacturing adhesives and sealants or sealants made of epoxidized, monohydroxylated diene polymers. More specifically, the invention relates to UJI solvent-free process for manufacturing UV-curable adhesives and sealants from epoxidized, monohydroxylated polydiene polymers which do not require the use of intensive mixing equipment.

BACKGROUND OF THE INVENTION The use of novel epoxidized monohydroxylated polydienes in UV-curable adhesive and sealant compositions is described in commonly assigned, co-pending International Patent Application PCT / EP 95/04012 (WO 96/11215). The polymers are combined with other ingredients such as a resin that provides stickiness or REF: 26540 adhesion to make them suitable for adhesive products and sealants or sealants. A photoinitiator is included in the combination to promote UV curing (cross-linking) of the composition. As described in the Examples of the aforementioned patent application, the components are dispersed in a solvent, usually THF, and then the adhesive films are melted or molded from the solution. The solvent was necessary because difficulties were encountered in mixing the photoinitiator (hexafluoroant imonate, bis (dodecylphenyl) iodonium) in the adhesive mixture because it was not readily compatible and could not be dispersed uniformly. THF was necessary to obtain effective UV curing - curing was ineffective in the absence of the solvent. For many applications, the use of solvents is undesirable because of the environmental risks and the cost of removing the solvent and the solvent itself. The present invention provides a free or solvent-free process for dispersing the insoluble photoinitiator so that an effectively cured adhesive or sealant is produced without these problems and without the need to use intensive mixing equipment.

DESCRIPTION OF THE INVENTION Therefore, the present invention relates to a solvent-free process for producing UV-curable sealant and adhesive compositions, comprising an epoxidized, monohydroxylated polydiene polymer, comprised of at least two polymerizable ethylenically unsaturated hydrocarbon monomers, wherein at least one is a diene monomer which produces the appropriate unsaturation by epoxidation, and wherein the polymer contains from 0.1 to 7.0 miluivalents of epoxy per gram of polymer, a monohydric of low molecular weight polydiene, an insoluble photoinitiator, and a resin that provides tackiness which is incompatible with the photoinitiator, the process comprises predispersing the photoinitiator in the monool or the polymer or a mixture of the two, and then adding the resin that provides stickiness to the predispersion. In this invention the epoxidized monohydroxylated polydiene polymer is used as the binder for the composition.

Preferred epoxidized monohydroxylated polymers are block copolymers of at least two conjugated dienes, preferably isoprene and butadiene, and optionally, a vinyl aromatic hydrocarbon wherein a hydroxyl group is attached or linked to one end of the polymer molecule. These polymers can be hydrogenated or non-hydrogenated. The sealant or adhesive composition comprises the epoxidized monohydroxylated polydiene polymer, a low molecular weight polydiene mono-ol, and ur > a r resin that provides tackiness or adhesion, adequate. The present process of incorporating in the composition of the above polymer, the mono-ol of diene, and the resin that provides adhesion, a photoinitiator which is insoluble in the adhesive formulation, such as a triaryl sulfonium salt, overcomes the difficulty in mixing the photoinitiator with the adhesive formulation. When mixed in the adhesive formulation, the photoinitiator forms large droplets and poor or insufficient curing with UV radiation is the result. This problem is overcome by predispersing the photoinitiator in a component or components of the formulation that are more chemically compatible (more compatible than the resin that provides tackiness), and then mixing with the rest of the ingredients of the formulation, that is, the resin that provides adhesion or stickiness. In the prior art, this predispersion could be carried out in a solvent. In the present invention, one of the components of the composition is used as the volumetric phase for dispersing fine droplets or droplets of the photoinitiator. In the preferred embodiment, the mono-ol (because it could usually be the material of lower viscosity in the starting composition) is heated, if necessary, to its lower viscosity, and then the photoinitiator is added and the predispersion it is agitated, but it is not agitated intensely. Polymers containing the ethylenic unsaturation can be prepared by copolymerizing one or more olefins, particularly diolefins, by themselves or with one or more monomers of alkenyl aromatic hydrocarbons. The copolymers can, of course, be random or not defined, tapered, blocks or a combination of these, as well as linear, star-shaped or radial. A process for the preparation of polymers derived from conjugated dienes and optionally aromatic vinyl hydrocarbons by anionic polymerization using lithium compounds as initiator is well known from US Pat. Nos. 4,039,593 and Re. 27,145. Polymerization begins with a monolithium initiator which constructs a living or living polymer structure at each lithium site or site. The specific processes for making these polymers are described in detail in the commonly assigned, co-pending international application, PCT / EP95 / 04012 (WO 96/11215). 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, methylpentadiene, phenylbutadiene, 3,4-dimethyl. -l, 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 vinyl aryl compounds such as styrene, various alkyl substituted styrenes, alkoxy substituted styrenes, vinyl naphthalene, alkyl substituted naphthalenes and the like.

The most preferred monohydroxylated polydiene polymer, from which the epoxidized monohydroxylated polydiene is derived, has the structural formula (I) (H0) x-A-S2-B- (0H) and wherein A and B are blocks of polymers which may be blocks of homopolymers of conjugated diolefin monomers, copolymer blocks of conjugated diolefin monomers, or copolymer blocks of diolefin monomers and monoalkenyl aromatic hydrocarbon monomers, wherein S is a block of aromatic vinyl hydrocarbon, where z = 0 or 1 and where x and y are 0 or 1, under the condition that either x or y must be 1, but only one at a time can be 1. These Polymers can contain up to 60% by weight of at least one vinyl aromatic hydrocarbon, preferably styrene. Generally, it is preferred that the A blocks have a higher concentration of more highly substituted aliphatic double bonds than the B blocks have. Thus, the blocks of A have a higher concentration of di-, tri- or tetra-substituted unsaturation sites (aliphatic double bonds) per block mass unit than the blocks of B. This produces a polymer where epoxidation is easiest occurs in the blocks of A. The blocks of A have a molecular weight of 100 to 6000, preferably of 500 to 4000, and more preferably of 1000 to 3000, and the blocks of B have the molecular weight of 1000 to 15,000, preferably from 2000 to 10,000, and more preferably from 3000 to 6000. The aromatic vinyl hydrocarbon block S which may have a molecular weight of 100 ^ to 10,000. Either the block of A or the block of B can be crowned with a polymer miniblock, molecular weight of 50 to 1000, of a different composition, to compensate for any initiation, which tapers due to unfavorable copolymerization rates, or crowning or covering difficulties. These polymers can be epoxidized so that they contain from 0.1 to 7.0 milliequivalents (meq) of epoxy per gram of polymer. The diblocks that fall within the above description are preferred. The total molecular weight of such diblock can vary from 1500 to 15000 and preferably from 3000 to 7000. One of the blocks in the diblock can contain some randomly polymerized vinyl aromatic hydrocarbons, as described above. For example, where I represents isoprene, B represents butadiene, S represents styrene, and a bar (/) represents a block of random copolymer, the diblocks may have the following structures: IB-OH IB / S-OH I / SB-OH II / B-OH or B / 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 where EB is hydrogenated butadiene, -EB / S-OH means that the hydroxyl source is bound or bound to a styrene mer, and -S / EB-OH means that the hydroxyl source is bound or bound to a hydrogenated butadiene mer. The latter case, -S / EB-OH, requires the coronation of the block of "random copolymer" of S / EB with a miniblock of Eb to compensate the tendency to taper styrene prior to coronation with ethylene oxide. These diblocks are advantageous because they exhibit lower viscosities and are as easy to manufacture as the corresponding triblock polymers. It is preferred that the hydroxyl is linked or attached to the butadiene block because the epoxidation proceeds more favorably with isoprene and there will be a separation between the functionalities on the polymer. However, the hydroxyl can also be attached or bonded to the isoprene block if desired. This produces a molecule more similar to the surfactant with less allowable load capacity. The isoprene blocks can also be hydrogenated. Certain triblock copolymers are also preferred for use here. Such triblocks usually include a randomly copolymerized styrene or styrene block to increase the glass transition temperature of the polymers, compatibility with polar materials, strength, and viscosity at room temperature. These triblocks include the following specific structures: I-EB / S-EB-OH IB / SB-OH IS-EB-OH ISB-OH OR II / SI-OH ISI-OH BSB-OH BB / SB-OH or IB / SI-OH I-EB / SI-OH or IBS-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) and where A, B, S, x, and y are as described above. These polymers and the other triblocks shown above are particularly advantageous for epoxy functional introduction blocks in the monohydroxylated polymers at multiple sites or sites. The epoxidation of the base polymer can be effected by the reaction with organic percents which can be preformed or formed in situ. Suitable preformed percents include peracetic and perbenzoic acids. The in situ formation can be terminated using hydrogen peroxide and a low molecular weight fatty acid such as formic acid. These and other methods are described in more detail in U.S. Patents 5,229,464 and 5,247,026. The epoxidation amount of these monohydric polydiene polymers ranges from 0.1 to 7 milliequivalents of epoxide per gram of polymer. Low levels are desirable to avoid overcuring. Levels of approximately 7 meq / g, stiffness, crosslink density, cost, manufacturing difficulty, and polarity of the polymer (so that certain monohydroxy diene polymers are not accepted) were found to be without benefit. The preferred amount of epoxidation is 0.5 to 5 meq / g and the most preferred amount of epoxidation is 1.0 to 3 meq / g. The most preferred amount balances the cure rate against overcuration and maintains better compatibility with a variety of formulation ingredients commonly used with polydiene-based adhesives. The molecular weights of linear polymers or non-assembled linear segments of polymers such as branches or arms of mono-, di-, triblock, etc., of star-shaped polymers before coupling or bonding are conveniently measured by Gel Permeation Chromatography. (CPG), where the CPG system has been properly calibrated. For anionically polymerized linear polymers, the polymer is essentially monodispersed (weighted average molecular weight / number average molecular weight ratio approaches unity), and it is both convenient and suitably descriptive to report the "peak" molecular weight of the molecular weight distribution barely enough, obsd. Usually, the peak value is between the number and the weight average. The peak molecular weight is the molecular weight of the main species shown on chromatography. For polydispersed polymers, the weighted average molecular weight should be calculated from the chromatograph and used. For materials used in the columns of the CPG, styrene-divinyl benzene gels or silica gels are commonly used and are excellent materials. Tetrahydrofuran is an excellent solvent for polymers of the type described herein. A refractive index detector can be used. If desired, these block copolymers can be partially hydrogenated. The hydrogenation can be selectively affected as described in the Republican US Patent 27,145. The hydrogenation of these polymers and copolymers can be carried out by a variety of well established processes including hydrogenation in the presence of such catalysts as noble metals, Raney Nickel, such as platinum and the like, soluble transition metal catalysts and titanium catalysts. as in U.S. Patent No. 5,039,755. 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 hydroxylated, partially unsaturated polymers are useful for further functionalization to make or manufacture the epoxidized polymers of this invention. The partial unsaturation is preferably such that 0.1 to 7 meq of aliphatic double bonds suitable for the epoxidation remain in the polymer. If the epoxidation occurs before the hydrogenation, then it is preferred that all remaining aliphatic double bonds are hydrogenated. It is highly advantageous to include a low molecular weight polydiene mono-ol in the composition to improve the stickiness or adhesion of the adhesive. Such mono-oles have a molecular weight of 2000 to 30, 000 and are polydiene polymers preferably hydrogenated with an OH terminal, such as polybutadiene or polyisoprene, monohydroxylated, hydrogenated. Preferred monools include those with a molecular weight range of 2000 to 10,000. The binders of this invention can be cured by cationic means using acid catalysts but are preferably cured by ultraviolet or electron beam radiation. Radiation curing using a wide variety of electromagnetic wavelengths is possible. Either ionization radiation such as alpha, beta, gamma, X rays and high energy electrons or radiation without ionization such as ultraviolet, visible, infrared, microwave and radio frequency can be used. A complete description of how this radiation can be effected is found in commonly assigned U.S. Patent 5,229,464.

When radiation without ionization is used, it is necessary to employ a photoinitiator to initiate the crosslinking reaction. Useful photoinitiators include dialkyl-4-hydroxyl-phenylsulfonium salts, diaryliodonium, diarylioxium substituted with alkoxy, triarylsulfonium, dialkylphenacylsulfonium. The anions in these salts generally have low nucleophilic character and include SbF6-, BF4-, PF6-, AsF6-, and B (C6F5) 4"(tetrakis (pentafluorophenyl) borate.) Specific examples include hexafluoroantimonato r of (4-octyloxyphenyl) ) -phenylliodonium, UVI-6990 (from UNLON CARBIDE), FX-512 (3M Company)., and photoinitiators SILCOLEASE UV200CATA (RHONE-POULENC Chemie). Bis (dodecylphenyl) iodonium hexafluoroantimonate, UV 9310 (GE), and , UVI-6974 (UNION CARBIDE), are especially effective (UNION CARBIDE, 3M, GE, RHONE POULENC, UVI, SILCOLEASE UV are registered trademarks.) Onium salts can be used alone or in conjunction with a photosensitizer that responds to lengths Long wavelengths of UV and visible light Examples of photosensitizers include thioxanthone, anthracene, perylene, phenothiazine, 1,2-benzatracene, coronene, pyrene and tetracene.If possible, the photoinitiator and photosensitizer are chosen to be compatible with the polymer / formulation that is crosslinked and a light source available. When this is not possible and the photoinitiator is insoluble in the formulation, the photoinitiator can be adequately dispersed in the formulation using the method described herein. As described in the examples of commonly assigned, co-pending international patent application PCT / EP95 / 04012 (WO 96/11215), an insoluble photoinitiator can be dispersed in a solvent in conjunction with the polymer and the tackifying resin to provide a composition which is effectively curable radiation ^. The present process does this without a solvent. One or more of the main components of this composition which are more chemically compatible with the photoinitiator, are used to form a predispersion of the photoinitiator. The photoinitiator is added to the most compatible component (s) and mixed thoroughly, but high shear or shear conditions are not necessary. This may require mild heating of the dispersion component (s). Then the other components are added. Surprisingly, it has been found that this process provides much more cured compositions than when the components are simply mixed in conjunction at the same time. It is preferred that mono-ol be used to form predispersion since it is one of the most compatible components and usually has the lowest viscosity to start or start, and therefore, mixes more easily. It is also very possible to use the epoxidized, monohydroxylated polymer to form the predispersion and also to use a mixture of mono-ol and the polymer. However, usually the tackifying resin is chemically incompatible with the photoinitiator and it is essential that it is not present when the photoinitiator is dispersed. Radiation-induced cationic curing can also be given in combination with curing of the free radical. The curing of the free radical can be further improved by the addition of additional free radical photoinitiators and photosensitizers. The process materials of the present invention are useful in pressure-sensitive adhesives and sealants or sealants (including packaging adhesives, contact adhesives, laminating adhesives, weather-resistant tapes, and mounting adhesives), and labels. It may be necessary for a formulator to combine a variety of ingredients together with the polymers of the present invention to obtain products having the appropriate combination of properties (such as adhesion, cohesion, durability, low cost, etc.) for particular applications. In more of these applications, the appropriate formulations must also contain various combinations of resins, plasticizers, fillers, solvents, stabilizers, and other ingredients such as asphalt. It is common practice to add a resin that provides tack or adhesion promoter that is compatible with the polymer, generally from 20 to 400 parts per hundred parts of polymer. Unfortunately, many of the useful photoinitiators are incompatible with many of the tackifying resins available. A common tackifying resin is a diene-olefin copolymer of piperylene and 2-methyl-2-butene having a softening point of about 95 ° C. This resin is commercially available under the trademark WINGTACK 95 (trademark) and is prepared by the cationic polymerization of 60% piperlene, 10% isoprene, 5% cyclo-pentadiene, 15% 2-methyl-2-butene and about 10% dimer, as taught in U.S. Patent No. 3,577,398. Other tackifying resins can be employed wherein the resinous copolymer comprises 20-80 weight percent piperylene and 80-20 weight percent 2-methyl-2-butene. The resins usually have softening points for the ball or sphere and ring as determined by the ASTM E28 method between 80 ° C and 115 ° C. Aromatic resins can also be employed as tackifiers, provided they are compatible with the particular polymer used in the formulation. Normally, these resins should also have ring and sphere or ball softening points between 80 ° C and 115 ° C although aromatic resin blends having high and low softening points can also be used. Useful resins include coumarona-indene resins, polystyrene resins, polyindene resins and vinyl toluene-alpha methylstyrene copolymers. The optional components of the present invention are stabilizers which inhibit or retard hot degradation, oxidation, formation of the final layer and color formation. Stabilizers are typically added to commercially available compounds to protect the polymers against hot degradation and oxidation during preparation, use and storage at elevated temperature of the composition. The adhesives are often thin layers of sticky or adherent compositions which are used in protected environments (adhesion of two substrates together). Therefore, the epoxidized, dehydrogenated polymers will usually have adequate stability of both the resin type and the concentration will be selected for maximum tackiness without further reference to stability, and pigments will not be used as usual. Seals or sealants are gap fillers. Therefore, they are not used in easily thick layers to fill the space between two substrates. Since the two substrates frequently move relative to each other, the sealants are in the usual form low modulus compositions capable of supporting this movement. Since sealants or sealants are often exposed to the weather, usually hydrogenated epoxidized polymers are used. Resins and plasticizers are selected to maintain a low modulus or coefficient and minimize sediment uptake. Fillers or fillers and pigments will be selected to give proper durability and color.

Since the sealants are applied in reasonably thick layers, the solvent content is as low as possible to minimize shrinkage or loss of volume.

EXAMPLES In the examples, various adhesive tests are used to demonstrate the properties of the test formulations using the improved r binders of this invention. The degree of covalent cure obtained for each sample of adhesives is measured by the use of a polymer gel contained in the test developed by JR Erickson for the radiation-cured adhesives, and first described in the article "Experimental Thermoplastic Rubbers for Enhanced Radiation Crosslinking of Hot Melt PSA's ", TAPPI 1985 Hot Melt Symposium Proceedings, June 1985. The method as practiced for the present examples is essentially identified with the method as published, but by a little less improvements and corrections to the method as it was published first. 180 ° Polishing of polished steel were determined using the Pressure Sensitive Tape Council Method No. 1. Higher values indicate high strength when peeling the coating of a test tape from the substrate. The polymer used herein is an epoxidized linear monohydroxy diene polymer, having a molecular weight of 6,000 with the structure I-EB-OH (MW of block 2000-4000) and hydroxyl of 0.17 meq / g and epoxy of 1.5 meq / g. The monoi used herein is a linear monohydroxy diene polymer with a molecular weight of 3,000 and the hydroxyl-containing EB-OH structure of 0.33 meq / g *. The incompatible photoinitiator described below was used. It is UVI 6974, a cationic photoinitiator of sulfonium salt made by UNION CARBIDE. The adherent agent was REGALREZ (Trade Mark) 1085, a resin that provides tackiness, - hydrogenated, made by HERCULES.

Example 1 Previous adhesives comprised of the polymer, mono-ol, REGLAREZ 1085, and UVI 6974 could not be UV cured unless mixed together with THF. This lack of curing was evidenced by the lack of cohesion of the adhesive. Essentially in the adhesive is a viscous liquid (goo) and when judged a test of pawness of the finger, the adhesive could simply be transferred to the finger. This operation is totally unacceptable. The first attempt to form UV-cured adhesives by predispersing the photoinitiator into mono-ol and then adding the remaining components provides a well-cured film that does not show adhesive transfer in the finger tack tests. In addition, the adhesive gave a 180 ° release to the steel value of 787.5 N / m without adhesive transfer. The adhesive clearly was well cured in contrast to its previous experience when the photoinitiator was added to all the components of the formulation at the same time. The suitable scattering event of the photoinitiator can be tested by visual observation of the dispersion after the photoinitiator is shaken. If the droplets, which are visible to the naked eye, are produced, the dispersion is not stable and phase separation occurs. Dispersions are also observed with an optical microscope. Only if the small droplets are formed can there be a stable dispersion and an effective UV curing; only then can useful adhesive properties be achieved. For this system, good dispersions are characterized by droplets of less than 20 microns with the volume of the distribution size that is between 1 and 10 microns. The above components are mixed individually with the photoinitiator to determine the level of dispersibility. The following table provides the conditions and results.

The data in the table indicates that the dispersibility is dependent on the chemical compatibility of the component with the photoinitiator. Viscosity was not a factor. It was possible to disperse the photoinitiator in the mono-ol or the polymer at room or elevated temperature. It was not possible to produce a stable dispersion of photoinitiator in the resin, even though the resin was heated to temperatures which lowered its viscosity and thus made it easy to mix.

Example 2 An adhesive formulation was first formed by dispersion of the photoinitiator in monool. The formulation was compressed of 12.65 grams of the monool, 0.25 grams of the photoinitiator, 12.15 grams of the polymer, 24.8 grams of the tackifying resin, and 0.075 grams of the antioxidant IRGANOX 1010 (registered trademark). A film was prepared from the formulation by melting it at 125C and curing it with UV radiation. The detachment at 180 was 4.5 pounds with adhesive failure. The degree of curing, as measured by the gel content (the percentage of the binder polymers that are covalently attached to the three-dimensional gel network), was 85%. This shows that a useful product was obtained. Other experiments where the components simply mixed together do not produce a curable composition.

It is noted that in relation to this date, the best method known by 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, the content of the following is claimed as property

Claims (7)

1. A solvent-free process for producing a UV-curable sealant or sealant or adhesive composition, comprising a monohydroxylated polydiene polymer, epoxidized, comprised of at least two polymerizable ethylenically unsaturated hydrocarbon monomers, wherein at least one is a monomer of diene which produces adequate unsaturation for the epoxidation, and where the polymer t contains from 0.1 to 7.0 milliequivalents of epoxy per gram of polymer, a monohydric of polydiene of low molecular weight, an insoluble photoinitiator, and a resin that provides which is incompatible with the photoinitiator, the process is characterized in that it comprises predispersing the photoinitiator in the monool or the polymer or a mixture of the two, and then adding the resin that provides stickiness or adhesion to the predispersion.

2. The process according to claim 1, characterized in that the epoxidized monohydroxy polymer is derived from an epoxidized monohydric polymer having the formula (HO) xA-Sz-B- (OH) and O (HO) xA-BS ( OH) and wherein A and B are blocks of polymers which may be blocks of homopolymers of conjugated diolefin monomers, copolymer blocks of conjugated diolefin monomers, or copolymer blocks of diolefin monomers and monoalkenyl aromatic hydrocarbon monomers, S is a block of aromatic vinyl hydrocarbon, x and y are 0 or 1 and either x or y must be 1 but only one at a time can be 1, and z is O or l.

3. The process in accordance with the claim 2, characterized in that the blocks of A have a molecular weight from 100 to 6000 and the blocks of B have a molecular weight from 1000 to 15,000.

4. The process according to claim 2, characterized in that A is isoprene, B is butadiene, and S is styrene.

5. The process according to claims 1-4, characterized in that the epoxidized monohydroxylated polymer is derived from a monohydroxylated diblock copolymer wherein the hydroxy group has been attached or bonded to the poly (butadiene) block.

6. The process according to claims 1-5, characterized in that the predispersion is formed by mixing the photoinitiator in the monool.

7. The process according to claim 6, characterized in that the predispersion is formed by mixing the photoinitiator in a mixture of the monool and the polymer.