MXPA97007865A - Complexes of organoganorous polioxyqualen polypoliamins and adhesive compositions made with the mis - Google Patents

Abstract

A complex comprising organoborane and polyoxyalkylene polyamine. The complexes are useful in systems for initiating the polymerization of the acrylic monomer, systems that adonally include an amine-reactive compound. Polymerizable acrylic monomer compositions suitable as adhesive can be prepared

Description

COMPLEXES OF ORGANOBORAMO POLIOXYALYL POLYPOLIAMINS v ADHESIVE COMPOSITIONS MADE WITH THEMSELVES Field of the Invention This invention relates, in general, to organoborane polyamine complexes and, more specifically, to those complexes that incorporate polyoxyalkylene polyamines. The invention also relates to the use of these complexes in systems for initiating the polymerization of acrylic monomers, as well as to adhesive, acrylic compositions made therefrom. Adhesive compositions have excellent adhesion to a variety of substrates, especially to low surface energy polymers.

Background of the Invention It has been reported that organoboranes such as tributylborane and triethylborane initiate and catalyze the polymerization of vinyl monomers (see, for example, GS Kolesnikov et al., Bull. Acad. Sci. USSR, Div. Chem. Sci. 1957, P. 653, J. Furakawa et al., Journal of Polymer Science, Volume 26, Issue 113, P. 234, 1957, and J. Furakawa et al.

REF: 25780 collaborators, Journal of Polymer Science, Volume 28, issue llß, 1958). The organoborane compounds of the type described in these references are known to be quite pyrophoric in air, which complicates their easy use. Chemical Abstracts No. 134385q (volume 80, 1974) "Bonding Polyolefin or Vinyl Polymers" reports that a mixture of 10 parts of methyl methacrylate, 0.2 parts of tributylborane, and 10 parts of poly (methylmethacrylate) was used to join copper rods. polyethylene, polypropylene and poly (vinyl acetate). US Patent No. 3,275,611 issued to E. H. Mottus et al. Describes a process for polymerizing olefinic compounds, with a catalyst comprising an organoboron compound, a peroxygen compound, and an amine. The organoboron compound and the amine can be added to the reaction mixture, separately, or can be added as a preformed complex. This last reported approach has the advantage of making the boron compound more easily manageable, especially for certain boron compounds that tend to be pyrophoric in air but are not pyrophoric when they are forming a complex.

It is said that boron catalysts, especially useful, have the following general formulas: R3B, RB (OR) 2, R2B (OR), R2BOBR2. R2BX, and R2BH, wherein R is preferably an alkyl radical having 1 to 10 or more carbon atoms, and X is a halogen. Several complex agents are mentioned above, based on amine, although in the examples pyridine, aniline, toluidine, dimethylbenzylamine, and nicotine are used. Although Mottus et al. Refers to the polymerization of methacrylate monomers, there is no indication that the resulting polymers are useful as adhesives. Various acids are mentioned as monomers that can be polymerized, but there is no indication that an acid is a component of the polymerization initiator system. British Patent Specification No. 1,113,722"Compositions that Can Be Polymerized Aerobically", published May 15, 1968, describes the polymerization of acrylate monomers through the use of a catalyst by free radicals (for example peroxides) and complexes of triarylborane having the general formula (R) 3B-Am wherein R is an aryl radical having from 6 to 12 carbon atoms and Am is an amine which can be selected from various classes such as alkylamines, cycloalkylamines, aralkylamines , polyamines (for example alkylene diamines and alkylenetriamines), and heterocyclic amines. The polymerization is activated by heat or by the addition of an acid. The resulting compositions are reported to be useful as adhesives. Chemical Abstracts No. 88532r (volume 73, 1970) "Autocurable Dental Resin" and the complete document to which it refers, reports that tributylborane can be made stable in air, complexing it or forming a complex with ammonia or certain amines (for example, with aniline, n-butylamine, piperidine, ethylenediamine) at a molar ratio of one and that the tributylborane can be reactivated with an amine acceptor such as an isocyanate, an acid chloride, a sulfonyl chloride, or anhydrous acetic acid. As a consequence, the complex can be used to polymerize mixtures of methyl methacrylate and poly (methyl methacrylate), to provide a dental adhesive. The tributylborane-ethylenediamine complexes and the triethylborane-ammonia complexes, each with p-toluenesulfonyl chloride, as the amine acceptor, are specifically mentioned.

A series of patents issued to S oultchi and Skoultc i and collaborators (U.S. Patents Nos. 5,106,928; 5,143,884; 5,286,821; 5,310,835; and ,376,746) describe a two-part initiator system, which, according to reports, is useful in acrylic adhesive compositions, especially in acrylic, elastomeric adhesives. The first part of this two part / system includes a stable organoborane amine complex, and the second part includes a destabilizer or activator such as an organic acid or an aldehyde-. The organ-borane compound of the complex has the general formula: "* wherein R, Rt and z are any alkyl-s-alkyl group having from 1 to 10 carbon atoms, or phenyl groups. Useful amines include n-oc ilamin-a, 1,6-diaminohexane, diethylamine, dibutylamine, diethylenetriamine, dipropylenediamine, 1,3-propylenediamine, and 1,2-propylenediamine. Adhesive compositions are reported to be particularly useful in structural and semi-structural applications, such as in speaker magnets, metal-metal bonding, glass-metal bonding (automotive applications), glass-glass bonding, bonding of sheet-metal components. printed circuits, adhesion of selected plastics with metals, glass, wood, etc., and electric motor magnets. Those plastics that can be attached or adhered are not described in additional form. For a long time, an efficient and effective means has been sought for adhesive bonding of low surface energy plastic substrates, such as polyethylene, polypropylene and polytetrafluoroethylene (for example, TEFLON). The difficulties in bonding these materials together are well known. See, for example, "Adhesion Problems on Polymeric Surfaces" by D.M. Brewis, which appeared in Progress in Rubber and Plastic Technology, volume 1, page 1 (1985). Conventional approaches typically work by: (1) increasing the surface energy of the substrate (to adjust more closely to the surface energies of the substrate and the adhesive, thereby promoting better wetting of the substrate by the adhesive) and / or (2) removing additives and fractions of low molecular weight polymers that are in the substrate, which can migrate to the surface of the substrate and adversely affect the adhesion forming a weak boundary layer. As a result, conventional approaches often use complex and costly substrate surface preparation techniques, such as flame treatment, corona discharge, plasma treatment, oxidation by ozone or oxidant acids, and jet etching of some material. Alternatively, the surface of the substrate can be prepared by coating it with a high surface energy material. However, in order to achieve adequate adhesion of the sizing, it may first be necessary to use the surface preparation techniques described above. All these techniques are well known as reported in Treatise on Adhesion and Adhesives (J.D. Minford, editor, Marcel Dekker, 1991, New York, volume 7, pages 333 to 435). The known approaches are often adjusted for use with specific substrates. As a result they may not be useful for bonding, generally, low surface energy plastic substrates. In addition, the complexity and cost of previously known approaches do not make them particularly suitable for use by retail consumers (for example, home restorers, do-it-yourselfers, etc.), or for low-volume work. An annoying problem is the repair of many cheap, everyday household items, which are made of polyethylene, polypropylene or polystyrene, such as garbage baskets, laundry baskets and toys. Consequently, a considerable need for a simple and easy-to-use adhesive has long been felt., which can easily bond or bond a wide variety of substrates, especially low surface energy materials such as polyethylene, polypropylene and polytetrafluoroethylene, without requiring a complicated preparation, sizing and similar preparations of the surface. It would also be considered useful for the adhesive to be able to bond a wide variety of different surfaces, including metals. Although an adhesive that can bond plastics of low surface energy is truly advantageous, the commercial utility of such an adhesive would increase if the components thereof could be combined in a convenient mixing ratio. This would allow the easy application of the adhesive using conventional containers for adhesives without the laborious weighing and manual mixing of the different components. However, the convenient mixing ratio should not be at the cost of significantly reduced storage stability or performance. Therefore, there is not only the need for an adhesive that can bond low surface energy plastics, but also the need for an adhesive that can be easily mixed at a convenient mixing ratio, without a material reduction in storage stability or in its operation.

BRIEF DESCRIPTION OF THE INVENTION The present invention relates to organoborane polyamine complexes, and more particularly, to those complexes including polyoxyalkylene polyamine. The complexes can be used in systems that initiate the polymerization of acrylic monomer to produce adhesive, acrylic compositions. Acrylic adhesive compositions have excellent adhesion to a wide variety of substrates but are especially useful for bonding low surface energy plastics (eg, polyethylene, polypropylene, polytetrafluoroethylene, etc.) which, to date, have been bonded or adhered using complex and expensive surface preparation techniques. In general, the complexes of the invention comprise organoborane and polyoxyalkylenepolyamine. The organoborane polyamine complexes have the general structure: wherein Am is polyoxyalkylene polyamine and has a structure selected from the group consisting of: H2NR0- (R50) w- (R60) x- (R50) and -R4NH2 (I) and [H2NR40- (R50) w] .- R7 (II).

In this structure, R1 is preferably an alkyl group having from 1 to 10 carbon atoms, and R2 and R3 are independently selected from alkyl groups having from 1 to 6 carbon atoms and from groups having phenyl, more preferably, R1, R "and R3 are alkyl groups having from 1 to 5 carbon atoms. most preferably, R1, R2 and R3 are the same R4, R5 and R6 are preferably alkylene groups having from 1 to 10 carbon atoms and which may be the same or different, most preferably R4 is a group alkyl having 2 to 4 carbon atoms, R5 is an alkyl group of 2 or 3 carbon atoms, and Rd is an alkyl group of 2 or 3 carbon atoms, R7 is a residue of a polyol. > 1 (most preferably from about 1 to 150, and most preferably from about 1 to 20.) The value of x and y is = 0. The value of z is > 2 (most preferably 3 or 4) The values for, x, and z are preferably selected such that the complex is a liquid at room temperature. accordingly, the molecular weight of the polyoxyalkylene polyamine is less than about 5,000, more preferably about 1,000 or less, and most preferably from about 250 to 1,000. The value of v is selected such that it provides an effective ratio of nitrogen atoms to boron atoms in the complex. In complexes employing polyoxyalkylenepolyamine (I), the value of v can vary widely through the range of about 0.1 to 2. In complexes employing polyoxyalkylenepolyamine (II), the value of v can vary widely throughout the range from about 0.1 to z. The ratio of nitrogen atoms to boron atoms, in the complex, should be from about 1: 1 to 4: 1, preferably from about 1: 1 to about 2: 1, preferably from about 1: 1 to 1.5: 1, and most preferably about 1: 1. The organoborane polyamine complexes of the invention can be used in systems that are capable of initiating the polymerization of an acrylic monomer. In addition to the organoborane polyamine complexes, such as those described above, these systems further comprise an effective amount of a compound that reacts with an amine, to release the organoborane. A wide variety of compounds can be used which react with amines, including isocyanates, acids, acid chloride, sulfonyl chlorides, and aldehydes. Useful acids include Lewis acids and Bronsted acids, although acrylic acid and methacrylic acid are preferred. The amount of the compound that reacts with the amine is preferably stoichiometric with respect to the equivalents of the amine, but larger amounts, for example, twice the stoichiometric amount, can be used. Where an acid provides the compound that reacts with the amine, a useful amount is in the range from about 350 mol%, more preferably from about 150 to 250 mol%. Accordingly, the invention also relates to a polymerizable acrylic composition, comprising at least one acrylic monomer, an effective amount of an organoborane polyamine complex, of the invention, and an effective amount of a compound that reacts with the amine (such as described above) to release the organoborane and to initiate the polymerization of at least one acrylic monomer. A wide variety of acrylic monomers may be used but those that are preferred include the monofunctional acrylate ester, the monofunctional methacrylate ester, substituted derivatives of the foregoing, and mixtures of the foregoing. Methacrylate esters are especially useful and particularly desirable examples thereof include methyl methacrylate, ethyl methacrylate, ethoxy ethyl methacrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, cyclohexyl methacrylate, tetrahydrofurphoryl methacrylate, and mixtures thereof. Mixtures of alkyl methacrylate (e.g., methyl methacrylate) and alkyl acrylate (especially those in which the alkyl group has from 4 to 10 carbon atoms, e.g., butyl acrylate) are also quite useful. The acrylic compositions of the invention are uniquely useful for providing adhesives, and the adhesive compositions of the invention provide excellent adhesion on low surface energy plastic or polymeric substrates, which have historically been very difficult to bond. Adhesion to low surface energy polymeric substrates increases when the adhesive composition comprises about 0.03 to 1.5 wt.% Boron, more preferably about 0.1 to 0.3 wt.% Boron. Accordingly, in another aspect, the invention relates to a composite article comprising a first substrate, a second substrate joined to the first substrate by an acrylic adhesive composition according to the invention. One or both substrates may be a low surface energy polymer or plastic, such as polyethylene, polypropylene or polytetrafluoroethylene. In another aspect, the invention relates to a method for initiating the polymerization of an acrylic monomer and the method comprises the steps of providing at least one acrylic monomer, mixing at least one acrylic monomer with a polymerization initiator system, in accordance with invention, and initiate the polymerization of at least one acrylic monomer. The invention further relates to a method for attaching a low surface energy polymer to a substrate. The method comprises the steps of providing a low surface energy polymer, providing a substrate, providing an adhesive composition according to the invention, applying the adhesive composition, either to the low surface energy polymer or to the substrate, bonding the low polymer. surface energy and the substrate, the adhesive composition remaining therebetween, and allowing the adhesive composition to cure to bond the low surface energy polymer and the substrate adhesively.

Detailed Description of the Preferred Modalities In a broad aspect this invention relates to organoborane polyamine complexes, particularly those complexes which are made of polyoxyalkylene polyamine. The complexes are especially useful for providing systems that serve to initiate the polymerization of an acrylic monomer. Acrylic adhesives can be produced using the organoborane polyamine complexes of the invention. Acrylic adhesives can bond or adhere a wide variety of substrates, but provide exceptionally good adhesion on low surface energy plastic substrates (eg, polyethylene, polypropylene, polytetrafluoroethylene, etc.) which, to date, have been bound using techniques of surface preparation, complex and expensive. The complexes of the invention are organoborane and polyoxyalkylene polyamine complexes preferably have the following general structure: wherein R1 is an alkyl group having from 1 to 10 carbon atoms, and R2 and R3 are independently selected from alkyl groups having from 1 to 10 carbon atoms and groups having phenyl. More preferably, R1, R2 and R3 are alkyl groups having from 1 to 5 'carbon atoms such as methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, and pentyl. In general, carbon chains of shorter lengths are preferred for groups R1, R2 and R3 since this promotes improved stability of the complex in air. Smaller and less bulky substituents are also preferred since larger and bulky groups may adversely affect the adhesion provided by the adhesives made therewith. By the term "independently selected" is meant that R1, R2 and R3 may be the same or different. R1 may be the same as R2 or R3, 6 may be different. Preferably R1, R2 and R3 are the same. The most preferred are the complexes in which R1, R2 and R3 are each ethyl groups. "Am" represents the polyoxyalkylene polyamine portion of the complex, and can be selected from the following structures: H2NR40- (R50) w- (RO) -x- (R50) and -R4NR2 I) (ie, polyoxyalkylene diamines) or [H2NR40-R50) w] z-R7 (II) Mixtures of different polyoxyalkylene polyamines can also be used. R4, R5 and R6 are alkylene groups having from 1 to 10 carbon atoms and can be the same or different. Preferably, R 4 is an alkyl group having 2 to 4 carbon atoms such as ethyl, n-propyl, isopropyl, n-butyl or isobutyl. Preferably, R5 is an alkyl group having 2 or 3 carbon atoms, such as ethyl, n-propyl or isobutyl. Preferably, R6 is an alkyl group having 2 or 3 carbon atoms, such as ethyl, n-propyl or isopropyl. R7 is the residue of a polyol used to prepare the polyoxyalkylene polyamine (ie, the organic structure that remains if the hydroxyl groups are removed). R7 can be branched or linear, saturated or unsaturated, and substituted or unsubstituted (although any substituents which are not to interfere with the oxyalkylation reactions). Residues that are branched, saturated and / or unsubstituted are preferred. The value of w is > 1, more preferably about 1 to 150, and most preferably about 1 to 20. Also useful are structures in which w is 2, 3 or 4. The value of x and y is for both > 0. The value of z is > 2, more preferably 3 or 4 (to provide, respectively, polyoxyalkylene triamines and polyoxyalkylene tetraamines). The selection of values for, x, y and z influence the physical form of the complex and the molecular weight of the polyoxyalkylene polyamine. It is preferred that the values of w, x, and z be selected such that the resulting complex is a liquid at room temperature, since this simplifies handling and mixing thereof. Usually, the polyoxyalkylene polyamine is itself a liquid. Polyoxyalkylene polyamines of lower molecular weights are also preferred, to promote the solubility of the complex in the compositions manufactured therewith and to improve the performance or operation of the final compositions incorporating the complex. Molecular weights of less than about 5,000 can be used, although molecular weights of about 1,000 or less are more preferred, but molecular weights of about 250 to 1,000 are most preferred. Examples of particularly preferred polyoxyalkylene polyamines include polyethylene oxide diamine, polypropylene oxide diamine, polypropylene oxide diethylene, diethylene glycol propylene diamine, triethylene glycol propylene diamine, polytetramethylene dioxide diamine, polyethylene oxide co-polypropylene oxide diamine, and polyethylene oxide co-polypropolenoxydotriamine. Examples of suitable commercially available polyoxyalkylene polyamines include various JEFFAMINES from Hunstman Chemical Company such as the diamines of the D, ED, and EDR series (e.g., D-400, D-2000, D-5000, ED-600, ED -900, ED-2001, and EDR-148), and the T series triamines (for example, T-403), as well as the H221 from Union Carbide Company.

The value of v is selected such that it provides an effective ratio of nitrogen atoms to boron atoms, in the complex, as explained more fully below. For the polyoxyalkylenepolyamine I, the value of v is preferably in the range from about 0.1 to 2. For the polyoxyalkylenepolyamine II, the value of v is preferably in the range of about 0.1 az, the value of z for any particular complex provides the upper limit of the preferred range for v. For the polyoxyalkylenepolyamine II, the value of v is preferably 3 or 4 when z is, respectively 3 or 4. The organoborane polyamine complexes, highly preferred according to the invention, include triethylborane, forming a complex with any of the polyoxyalkylene polyamines " particularly preferred ", mentioned above. The ratio of nitrogen atoms to boron atoms in the complex is from about 1: 1 to 4: 1. However, preferably, the ratio is from about 1: 1 to 2: 1, more preferably from about 1: 1 to 1.5: 1, and most preferably about 1: 1. A ratio of nitrogen atoms to boron atoms, less than 1: 1, leaves free organoborane and this is a material that tends to be pyrophoric. When there are relations of nitrogen atoms to boron atoms, which are found by 2: 1, the practical utility of the complex, for example in an adhesive system, decreases as the amount of the complex that must be used to generate a useful adhesive , becomes larger. In addition, at high ratios of nitrogen atoms to boron atoms, the amount of the agent that must be added to react with the polyamine, such that organoborane is released (to initiate polymerization), also becomes larger. Additional reactants may complicate the adhesive system. The organoborane polyamine complex is employed in an effective amount, which is an amount large enough to allow the polymerization to occur easily, to obtain a polymer (preferably, an acrylic polymer) of a molecular weight high enough for the end use wanted. If the amount of organoborane polyamine complex is too low, then the polymerization may be incomplete or, in the case of the adhesives, the resulting composition may have poor adhesion. On the other hand, if the amount of organoborane polyamine complex is too high, then the polymerization can be carried out in too fast a manner such that effective mixing and use of the resulting composition is not allowed. Also, larger amounts of complex could lead to the generation of large volumes of borane, which in case of an adhesive, could weaken the bonding or adhesion line. The rate of polymerization, useful, will depend in part on the method of application of the composition on the substrate. Thus, a faster polymerization rate can be accommodated using an automated, high-speed, industrial adhesive applicator, rather than applying the composition with a hand-held applicator or manually mixing the composition. Within these parameters, and in the particular case of an adhesive, an effective amount of the organoborane polyamine complex is an amount that preferably provides about 0.03 to 1.5% by weight of boron, based on the total weight of the adhesive composition, in more preferably from about 0.1 to 0.3% by weight of boron.

The% by weight of boron in a composition is equal to the following: (weight of the complex (% by weight of boron X in the composition in the complex) (Total weight of the composition) The organoborane polyamine complexes can be easily prepared using known techniques. Typically, the polyamine is combined with the organoborane in an inert atmosphere, with slow stirring. An exotherm is often observed and therefore the cooling of the mixture is recommended. If the ingredients have a high vapor pressure it is desirable to keep the reaction temperature below about 70 to 80 ° C. Once the materials have been mixed well with the complex, cooling is allowed up to room temperature. No special storage conditions are required although it is preferred that the complex be kept in a covered container, in a dark and cold place. Advantageously, the complexes of the invention can be prepared in the absence of organic solvents which would then have to be removed, although they could be prepared in a solvent, if desired. The solvents used in the preparation of complexes should be those that do not form coordination compounds with the amines, for example, tetrahydrofuran or hexane. Advantageously, the preferred organoborane polyamine complexes of the invention are stable in the air. By "stable in the air" it is meant that when the complexes are stored in a covered container at room temperature (approximately 20 to 22 ° C) and under different environmental conditions (ie, not under vacuum and not in an atmosphere inert), the complexes remain useful as polymerization initiators for at least about two weeks, although the complexes can be easily stored under these conditions for several months and up to a year or more. By the term "stable in the air" it is also understood that the complexes are not pyrophoric, as explained more fully below. The stability in the air, of the complex, is increased when the complex is a crystalline material. However, the complexes of the invention are stable in the air for at least six months, even when they are liquid. Liquid complexes are easier to manipulate and mix than crystalline complexes.

As indicated above, the organoborane polyamine complexes of the invention are especially useful as polymerization initiators, in particular, to initiate the polymerization of the acrylic monomer. In these cases, the organoborane polyamine complexes form a component of a polymerization initiator system, which comprises, and more preferably, consists essentially of an effective amount of the organoborane polyamine complex and of an effective amount of a compound that can react with an amine to release organoborane, to initiate polymerization. The compound that reacts as an amine releases organoborane by reacting with the polyamine, whereby the organoborane is removed from a chemical bond with the polyamine. A wide variety of materials can be used to provide the compound that reacts with the amine. The compounds which react with the amine, which are desirable, are those materials which can easily form reaction products with amines at room temperature (from about 20 to 22 ° C) or below it (preferably at room temperature) to provide a composition such as an adhesive that can be easily used and that cures easily under ambient conditions. The general classes of those compounds include isocyanate, acid chloride, sulfonyl chloride, aldehyde, and the like. Particular examples of compounds falling within these general classes include toluene diisocyanate, benzaldehyde, and methacryloyl chloro. The compound that reacts with the amine is used in an effective amount; that is, an amount effective to promote polymerization by the organoborane release of the complex, but without materially and adversely affecting the properties of the latter polymerized composition. Larger amounts of the compound that reacts with the amine may allow the polymerization to proceed too quickly and, in the case of adhesives, the resulting materials may demonstrate or exhibit inadequate adhesion to low energy surfaces. Also, using larger amounts of the compound that reacts with the amine may result in undesirable side reactions that adversely affect the performance properties of the polymerized composition, or an undesirably high level of extractables, in the polymerized composition. On the other hand, an excess of certain compounds that react with the amine can promote adhesion on higher energy surfaces. If small amounts of the compound which reacts with the amine are used, the speed of the polymerization may be too slow and the monomers being polymerized may not increase adequately to generate a higher molecular weight. However, a reduced amount of the compound that reacts with the amine can help decrease the polymerization rate if it is very fast. Within these parameters, the compound which reacts with the amine may be provided in an amount in which the number of equivalents of the groups reacting with the amine is at most twice the stoichiometric amount relative to the number of amine groups that are find in the organoborane polyamine complex. However, it is much more preferred that the number of equivalents of the groups reacting with the amine be stoichiometric with respect to the number of amine groups found in the organoborane polyamine complex. Acids can also be used, such as the compound that reacts with the amine. Any acid that can be released by the organoborane can also be used by the salt displacement of the polyamine group. Useful acids include Lewis acids (eg, SnCl4, TiCl4 and the like) and Bronsted acids such as those having the general formula R8-C0OH, wherein R8 is hydrogen, an alkenyl group of 1 to 8 carbon atoms. carbon and preferably from 1 to carbon atoms, or an aryl group of 6 to 10 carbon atoms, preferably of β to 8 carbon atoms. The alkenyl groups can comprise a straight chain or can be branched chain. They can be saturated or unsaturated. The aryl groups may contain substituents such as the alkyl, alkoxy or halogen moieties. Illustrative acids of this type include acrylic acid, methacrylic acid, acetic acid, benzoic acid, and p-methoxybenzoic acid. Other useful Bronsted acids include HCl, H2SO4, H3P04 and the like. Acrylic acid and methacrylic acid are preferred. A somewhat different formulation form is preferred, with acids which are preferably provided in an amount of about 100 to 350 mol%, based on the number of equivalents of groups, portions or functionality, amine, present in the complex, more preferably about 150 to 250 mol%.

The organoborane polyamine complex initiator systems of the invention are especially useful in the polymerization of acrylic monomers, particularly for making polymerizable acrylic adhesives. By the term "acrylic monomer" is meant polymerizable monomers having one or more portions, chemical groups or functionality, acrylic or substituted acrylic; that is, groups having the general structure: R O H2C = C-C-0-R 'wherein R is hydrogen or an organic radical and R' is an organic radical. Where R and R 'are organic radicals, these may be the same or different. Mixtures of acrylic monomers can also be used. The polymerizable acrylic monomer can be monofunctional, polyfunctional or a combination thereof. The most useful monomers are monofunctional, acrylate and methacrylate esters, and substituted derivatives thereof such as hydroxy, amide, cyano, chlorine, and silane derivatives, as well as monofunctional, substituted, and substituted acrylate and methacrylate esters. not replaced. Particularly preferred monomers include the lower molecular weight methacrylate esters, such as methyl methacrylate, ethyl methacrylate, methoxyethyl methacrylate, hydroxyethyl methacrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, cyclohexyl methacrylate, tetrahydrofurfuryl methacrylate, and mixtures thereof. Both acrylate esters and higher molecular weight methacrylate esters are less preferred for use alone, but can be used especially useful as modifying monomers, with predominant amounts of lower molecular weight methacrylate esters to increase, for example, the softness or flexibility of the final composition. Examples of those higher molecular weight acrylate esters and methacrylate esters include methyl acrylate, ethyl acrylate, isobornyl methacrylate, hydroxypropyl acrylate, butyl acrylate, n-octyl acrylate, 2-ethylhexyl acrylate, methacrylate. of 2-ethylhexyl, decyl methacrylate, docecyl methacrylate, tert-butyl methacrylate, acrylamide, N-methylacrylamide, diacetoneacrylamide, N-tert-butyl acrylamide, N-tert-octylacrylamide, N-butoxy-acrylamide, gamma-methacryloxypropyltrimethoxysilane, 2-cyanoethyl acrylate, 3-cyanopropyl acrylate, tetrahydrofurfuryl chloroacrylate, glycidyl acrylate, glycidyl methacrylate, and the like. Dimethylaminoethyl acrylate and dimethylamino methacrylate can also be used as modifying agents, although the additional amine functionality may require a greater amount of the compound that reacts with the amine. Particularly preferred are mixtures of any of the alkyl methacrylate esters of lower molecular weight, described above, with alkyl acrylates having from 4 to 10 carbon atoms in the alkyl group, such as mixtures of methyl methacrylate and sodium acrylate. butyl. Polymerizable compositions of this type can broadly comprise, based on the total weight of the composition, about 2 to 40% by weight of the alkyl acrylate, and correspondingly, about 60 to 98% by weight of the alkyl methacrylate. Another class of polymerizable monomers that are especially useful as modifiers, such as to improve the slip resistance or temperature resistance of the final composition, corresponds to the general formula: R9 can be selected from the group consisting of hydrogen, methyl, ethyl, -CH20H, and , or can be selected from the group consisting of chlorine, methyl and ethyl. R 11 can be selected from the group consisting of hydrogen, hydroxy, and The value of a is an integer greater than or equal to 1, more preferably, from 1 to about 8, and most preferably from 1 to 4. The integral value of b is greater than or equal to 1, in form more preferably from 1 to about 20. The value of c is 0 or 1. Other acrylic monomers useful with the polymerization initiator systems, especially as modifying monomers, include ethylene glycol dimethacrylate, ethylene glycol diacrylate, polyethylene glycol diacrylate, tetraethylene glycol dimethacrylate, diglycerol diacrylate, diethylene glycol dimethacrylate, pentaerythritol triacrylate, trimethylolpropane trimethacrylate, as well as other polyether diacrylates and dimethacrylates. Other polymerizable monomers which are useful in the invention, particularly as modifying monomers, have the general formula: R 12 can be hydrogen, chlorine, methyl or ethyl; R 13 can be an alkylene group with an amount of 2 to 6 carbon atoms; and R14 is (CH2) "where e is an integer from 0 to 8, or one of the following: CH, \ / Of H CH; H the phenyl group can be substituted in any of the ortho, meta or para positions. The value of d is an integer from 1 to 4. Typical monomers of this class include bis (ethylene glycol) adipate dimethacrylate, bis (ethylene glycol) maleate dimethacrylate, bis (ethylene glycol) phthalate dimethacrylate, bis (tetraethylene glycol) dimethacrylate ) phthalate, bis (tetraethylene glycol) sebacate dimethacrylate, bis (tetraethylene glycol) maleate dimethacrylates, and the diacrylates and chloroacrylates corresponding to the dimethacrylates, and the like. Also useful as modifying agents are the monomers which are the products of the isocyanate-hydroxyacrylate or isocyanato-aminoacrylate reaction. These can be characterized as being polyurethanes terminated in acrylate and polyureas or polyureas. These monomers have the following general formula: where X is selected from the group consisting of and R is selected from the group consisting of hydrogen and lower alkyl groups (for example, from 1 to 7 carbon atoms). T is the organic residue of an acrylic ester, which contains active hydrogen, wherein the active hydrogen has been removed and the ester has been substituted by hydroxy or amino, in the alkyl portion thereof (including methyl, ethyl and homologs of the chlorine). The integral value of f is from 1 to 6. L is a monovalent or polyvalent organic radical selected from the group consisting of alkyl, alkylene, alkenyl, cycloalkyl, cycloalkylene, aryl, aralkyl, alkaryl, poly (oxyalkylene), poly (carboalkoxyalkylene) , and heterocyclic radicals, both substituted and unsubstituted. Typical monomers of this class include the reaction product of monoisocyanates or polyisocyanates, for example, toluene diisocyanate, with an acrylate ester containing a hydroxy group or an amino group in the non-acrylate portion thereof, example, hydroxyethyl methacrylate. Still another class of modifying monomers, useful in the present invention, are the bisphenol ester compounds of monoacrylate and polyacrylate, and methacrylate. These monomers can be described by the following formula: wherein R16 is methyl, ethyl, carboxyalkyl or hydrogen; R17 is hydrogen, methyl or ethyl; R18 is hydrogen, methyl or hydroxyl; R19 is hydrogen, chlorine, methyl or ethyl; and g is an integer having a value from 0 to 8. Representative monomers of the class described above include dimethacrylate and diacrylate esters of 4, '-bis-hydroxyethoxy-bisphenol A, dimethacrylate and bisphenol A diacrylate esters, etc. . The compositions may optionally comprise a variety of optional additives. A particularly useful additive is a thickener such as a polymethyl methacrylate of average molecular weight (eg, about 100,000) which can be incorporated in an amount of about 10 to 40% by weight, and based on the total weight of the composition. Thickeners can be used to increase the viscosity of the composition to a syrup-like, viscous consistency, more easily applicable. Another particularly useful additive is an elastomeric material. These materials can improve the fracture resistance of the compositions made therewith which can be beneficial when, for example, rigid, high yield strength materials such as metal substrates are joined which do not mechanically absorb energy as easily as other materials, such as as polymeric, flexible substrates. These additives may be incorporated in an amount of about 5% to 35% by weight, based on the total weight of the composition. Useful elastomeric modifiers include chlorinated or chlorosulfonated polyethylenes such as HYPALON 30 (commercially available from E. I. duPont de Nemours and Co., Wilmington DE). Also, and even more preferred, are certain graft copolymer resins such as particles comprising rubber or rubber-like cores or networks that are surrounded by relatively hard shells, these materials are often referred to as "core-shell" polymers. The most preferred are acrylonitrile-butadiene-styrene graft copolymers. In addition to improving strength in the fracture of the composition, the core-shell polymers can also impart improved diffusion and flow properties to the uncured composition. These improved properties can be manifested by a reduced tendency of the composition to leave an undesirable "cord" in the administration from a syringe-type applicator, or sinking or depression after it has been applied to a vertical surface. The use of more than about 20% of a core-shell polymer additive is desirable to achieve the improved subsidence-depression resistance. Another useful adjuvant is a crosslinking agent. Crosslinking agents can be used to improve the solvent resistance of the adhesive bond, although certain compositions of the invention have good solvent resistance even in the presence of externally added crosslinking agents. Typically employed in an amount of about 0.2 to 10% by weight based on the total weight of the composition, useful crosslinking agents include the various diacrylates referred to above as possible modified acrylic monomers as well as other materials. Particular examples of suitable crosslinking agents include ethylene glycol dimethacrylate, ethylene glycol diacrylate, triethylene glycol dimethacrylate, diethylene glycol bismethacryloxy carbonate, polyethylene glycol diacrylate, tetraethylene glycol dimethacrylate, diglycerol diacrylate, diethylene glycol dimethacrylate, pentaerythritol triacrylate, trimethylolpropane trimethacrylate. , as well as other polyether diacrylates and dimethacrylates. Peroxides can optionally be included (typically in an amount of about 2% by weight or less, based on the total weight of the composition), for example, to adjust the rate at which the compositions polymerize or to terminate the polymerization.

For example, small amounts of inhibitors such as hydroquinone can be used to prevent or reduce the degradation of acrylic monomers during storage. Inhibitors may be added in an amount that does not materially reduce the polymerization rate or the final properties of an adhesive or other composition made therefrom, typically around 100-10,000 ppm based on the weight of the polymerizable monomers. Other possible additives include non-reactive dyes, fillers (e.g., carbon black), etc. Various optional additives are employed in an amount that does not significantly adversely affect the polymerization process or the desired properties of the compositions made therewith. The polymerizable acrylic compositions according to the invention can be used in a wide variety of ways, including as sealants, coatings and injection molding resins. They can also be used as matrix resins in conjunction with glass fiber and metal mats, such as in resin transfer molding operations.

They can be further used as encapsulants and encapsulation compounds such as in the manufacture of electrical components, boards and printed circuits and the like. In a completely desirable manner, they provide adhesive, acrylic, polymerizable compositions which can be attached to a diverse myriad of substrates, including polymers, wood, ceramic products, concrete and ready-made metals. The polymerizable acrylic compositions of the invention are especially useful for the adhesive bonding of low surface energy plastic or polymeric substrates that have historically been very difficult to bond without using complicated surface preparation, priming, etc. techniques. By low surface energy substrates it is meant materials having a surface energy of less than 45 mJ / m2, more typically less than 40 mJ / m2 or less than 35 mJ / m2. (The term "surface energy" is often used synonymously with "critical wetting tension" or others). Included among these materials are polyethylene, polypropylene, acrylonitrile-butadiene-styrene, polyamide and fluorinated polymers such as polytetrafluoroethylene (TEFLON) having surface energy of less than 20 mJ / m2. Other polymers of somewhat high surface energy that can be usefully linked with the compositions of the invention include polycarbonate, polymethylmethacrylate and polyvinylchloride. The polymerizable compositions of the invention can be easily used as two-part adhesives. The components of the polymerizable composition are mixed as would normally be done with the other materials. The reactive amine component of the polymerization initiator system is usually included in this mixture to separate them from the organoborane polyamine complex, thus providing a part of the two part composition. The organoborane polyamine complex of the polymerization initiator system provides the second part of the composition and is added to the first part briefly before it is desired to use the composition. The complex can be added to the first part directly or can be pre-dissolved in an appropriate carrier such as a small amount of methyl methacrylate. While a ratio of nitrogen atoms to boron atoms of about 1: 1 in the organoborane polyamine complex is preferred, it is desirable to store these complexes separately from the monomers to inhibit the premature polymerization of the monomers. Complexes in which the ratio of nitrogen atoms to boron atoms is greater than 1: 1 can be sufficiently stable that they can be mixed with the acrylic monomer in useful proportions. Nevertheless, in these situations, the presence of additional non-polymerizing reagents (e.g., the reactive amine compound) may result in other undesirable effects. For a two-part adhesive such as those of the invention to be used more easily in commercial and industrial environments, the ratio in which the two parts are combined must be a convenient whole number. This facilitates the application of the adhesive with conventional, commercially available administrators. These administrators are shown in US Patents Nos. 4,538,920 and 5,082,147 and are available from Conprotec, Inc., (Salem, NH), under the trademark "Mixpac". Typically, these administrators are a pair of tubular receptacles arranged side by side with each tube that is proposed to receive one of the two parts of the adhesive. Two pistons one for each tube, are advanced simultaneously (for example, manually or by a differential movement mechanism, operated by the hand) to evacuate the contents of the tubes in a mixing chamber, elongated, hollow, common that It can also contain a static mixer to facilitate the mixing of the two parts. The mixed adhesive is extruded from the mixing chamber onto a substrate. Once the tubes have been emptied, they can be replaced with fresh tubes and the application process is continued. The ratio to which the two parts of the adhesive are combined is controlled by the diameter of the tubes (each piston is dimensioned to be received inside a fixed diameter tube, and the pistons are advanced in the tubes at the same speed ). Frequently, an individual administrator is proposed for use with a variety of different two-part adhesives, and the plungers are sized to deliver the two parts of the adhesive to a convenient mixing ratio. Some common mixing ratios are 1: 1, 2: 1, 4: 1 and 10: 1. If the two parts of the adhesive are combined in a rare mixing ratio (eg, 100: 3.5), then the end user will probably will manually measure the two parts of the adhesive. In this way, for the best commercial and industrial utility and for ease of use with the currently available administering equipment, the two parts of the adhesive must be capable of being combined in a common, whole number mixing ratio, such as 10: 1 or less, more preferably 4: 1, 3: 1, 2: 1 or 1: 1. The adhesive compositions of the invention are only suitable for use with conventional administration equipment, commercially available for two-part adhesives. The organoborane polyamine complexes of the invention have a relatively high molecular weight (as compared to other organoborane polyamine complexes). Accordingly, the complex can essentially comprise all of the second part of the adhesive while still providing an effective amount of organoborane in a useful, integer mixing ratio of 10: 1 or less. Once the two parts have been combined, the composition should be used quickly, since pot time can be short depending on the acrylic monomer mixture, the amount of complex, and the temperature at which it is going to be used. perform the union. The polymerizable composition is applied to one or both substrates and then the substrates are joined together with pressure to force the excess composition out of the bond line. This also has the advantage of displacing the composition that has been exposed to air and may have begun to oxidize. In general, the bonds should be made briefly after the composition has been applied, preferably within the space of about 10 minutes. The typical bond line thickness is approximately 0.1 to 0.3 mm. The bonding process can be carried out easily at room temperature and to improve the degree of polymerization it is desirable to keep the temperature below about 40 ° C, preferably below 30 ° C, and most preferably below 25 ° C. The joints will cure to a reasonable strength before curing to allow the handling of the bonded components of the space of approximately 2 to 3 hours. The complete resistance will be reached in approximately 24 hours under ambient conditions; post-cure with heat (typically around 80 ° C) can be used if desired. When fluoroplastics are attached, it is advantageous to cool the first part of the two part composition to about 0 to 5 ° C before adding the organoborane polyamine complex. The bond should be made as soon as convenient after the composition has been applied; performing the joining operation at less than room temperature is also useful. The invention will be more fully appreciated with reference to the following non-limiting examples in which (unless otherwise stated) all weights are given as hundreds per hundred weight (% by weight), based on the total weight of the composition which is 100% by weight, and are reported to two significant digits following the decimal point. Examples that were subsequently evaluated to measure the resistance to polishing stress of the adhesive bonds were tested as described below.

Test Method of Resistance to Polishing Effort The test specimens used are similar to those described in ASTM D-1002 except that the specimens were generated using digital panels of nominal dimensions 1 inch x 4 inches x 1/8 inch thick (2.5 cm x 10.2 cm x 0.3 cm thick). Red, lithograph tapes, 0.5 inch (1.3 cm) wide, were applied to the end of one of the adherents in order to help fix the joint and also to assist in manufacturing the polishing region to be 0.5 inch ( 1.3 cm). Short pieces of 6 mm diameter (0.15 mm) diameter piano cord were cut for use as spacers to control the thickness of the adhesive bond line. The adhesive was prepared by weighing the monomer mixture in a flask that was capable of being sealed with a poly cap. Then the organoborane polyamine initiator complex was added, mixed with the monomer mixture using a wooden stick, and the bottle was sealed with the poly cap. In general, the addition of the organoborane polyamine amine initiator complex to the monomer mixture caused the mixture to be slightly exothermic and in some cases turned yellow. A bit of mixed adhesive was applied to each adhesive and spread to ensure that an area of 1 inch x 0.5 inch (2.5 cm x 1.3 cm) was covered at the end of each adhesive. Two pieces of piano string were placed on the adhesive in an adhesive and the joint was closed and fixed with the lithograph tape. The joint was additionally fixed with two clamps and allowed to cure at room temperature for 48 hours at which time the clamps and the tapes were removed. The polishing stress test was performed with three types of adhesion: mechanical grade TEFLON, high density polyethylene, and polypropylene, as available from Precision Punch and Plastic Co. (Minneapolis, MN). Three adhesive bonds were made with each adhesive and each adhesive combination. For each adhesive, the TEFLON was bonded first, then the high density polyethylene, and then the polypropylene. After healing, the joints were tested for failure using a tensile testing machine. The crosshead speed was 0.1 inch / minute (2.5 mm / min) and the tests were carried out at room temperature. The joints were inspected visually, after they were loaded, for the fault to determine the failure mode. The failure of the adherents is the most preferred although the cohesive failure of the composition indicates a useful formulation. Failure modes are reported in the examples based on a series of coded abbreviations that can be interpreted as follows: Example 1 In Example 1, the organoborane polyamine complexes were synthesized. All glass utensils were washed and baked at 1000 ° F (538 ° C) or burned by means of a Bunsen burner until the glass utensil turned orange. A bag of polyethylene gloves was placed in the hood and flooded with nitrogen. (In some cases, the synthesis was carried in a glovebox that has become inert with nitrogen). The glove bag or glove box contained a pressure equalizing drop funnel, an electric counterweight, a flask with appropriate stoppers and a support. The polyoxyalkylene polyamine was degassed by freeze-thaw cycles under vacuum and then weighed into the flask. The organoborane was weighed in the pressure equalization dropping funnel and then added dropwise to the polyamine with stirring and cooling. A mild exotherm was observed and the reaction mixture was alternately clear and cloudy. The organoborane addition was moderated to control the exotherm. In some cases, the formation of smoke occurred and the addition of borane was decreased until the formation of smoke has decreased. Once all the organoborane was added, the flask was allowed to come to room temperature until either a liquid or a crystalline mass was obtained. If a crystalline mass was obtained, it was heated to 55 ° C by means of an oil bath outside the glove bag to liquefy it so that it could be transferred. A misty white liquid resulted, which was poured into a flask previously flooded with nitrogen. After cooling, a crystalline, white material was obtained, if the result was not a crystalline mass, then the liquid was poured from the flask into a bottle and sealed.

The complexes were made with the organoboranes and the polyamines listed below in Table 1. For each complex, the ratio of boron atoms to nitrogen atoms was 1: 1 (i.e., one mole of trialkylborane for each equivalent of amine functionality). The complexes were examined for pyrophoricity. Drops of liquid samples were placed on paper towels that were then placed in a fume hood. The samples were observed for 24 hours. Any ignition is indicated in Table 1. In one case, the catalyst did not ignite the paper towel until the paper was bonded against a waxed floor. Most of the organoborane polyamine complexes of the invention are stable to air and do not ignite combustible materials.

Table 1 (H211 is commercially available from Union Carbide Company The "Jeffamine" line of products is commercially available from Huntsman Chemical Company).

Example 2 A series of adhesive compositions was prepared using different complexes of Table 1 (each based on tri-n-butyl-borane) and the following monomer mixture: 74 g of methyl methacrylate, 56 g of n-butyl acrylate, 60 g of poly (methyl methacrylate) of average molecular weight ) (poly (methyl methacrylate-co-ethylacrylate) of a molecular weight of 101,000) with less than 5% ethyl acrylate from Aldrich Chemical Co. ), and 6 g of methacrylic acid. The components of the monomer mixture were weighed into a one-quarter brown bottle which was then sealed and placed overnight in a Launder-o meter that was adjusted to 55 ° C. It turned out a moderately viscous solution, from light yellow to white, clear. This was referred to as the A mixture of monomers. Using the techniques described above, 5 g of mixture A of monomers were combined with various organoborane polyamine complexes to provide the adhesive compositions that were tested for polishing strength. In each case, the complex provided approximately 0.2% by weight of boron in the adhesive. The results are reported in Table 2 in pounds per square inch (psi).

Table 2 Example 2 shows that the organoborane polyamine complexes of the invention can be used to prepare acrylic adhesive compositions which provide high strength bonds to low surface energy plastic substrates. In some cases, the resistance to polishing stress exceeded the elastic limit of the substrate.

Example 3 Using the techniques described above, 5 g of monomer mixture A was used (see Example 2) with various organoborane polyamine complexes of Table 1 to provide adhesive compositions that were tested for polishing stress resistance. In each case, the complex provided approximately 0.26% by weight of boron in the adhesive and the complex was based on triethylborane rather than tri-n-butylborane as used in Example 2. The results are reported in Table 3 below.

Table 3 Table 3 indicates that useful adhesive compositions can also be made when the organoborane is triethylborane.

Example 4 The organoborane polyamine complexes are prone to degradation during storage due to the possible oxidation of the organoborane. However, as shown below, the complexes of the invention demonstrate excellent storage stability, even when kept under ambient conditions, at room temperature, for more than six months. More specifically, adhesive compositions similar to those in Example 2 were prepared as described above except that organoborane polyamine complexes were used which were first stored under ambient conditions, at room temperature for about 6 months. Each example was based on 5 g of mixture A of monomers and a sufficient amount of complex to provide about 0.21% by weight of boron to the adhesive composition. The adhesive compositions were then placed and tested as described in conjunction with Example 2, with the results shown below in Table 4.

Table 4 The good adhesive performance shown by Table 4 was promoted by separately storing the monomers and the complex.

Example 5 Using the methods described above, mixture A of monomers (see Table 2) was combined with various organoborane polyamine complexes from Table 1, to provide adhesive compositions that were tested for polishing resistance. In each case, the complex and the monomer mixture were mixed in a weight ratio of 10: 1 (ie, 5 g of monomer mixture A + 0.5 g of complex). The results are reported in Table 5.

Table 5 Table 5 shows that the adhesive compositions according to the invention and that can provide acceptable bond strengths and acceptable failure modes can be obtained when complexes of organoborane polyamine are combined with acrylic monomers in a mixing ratio of 10: 1, industrially Useful.

Example 6 In Example 6, 5 g of mixture A of monomers were combined with different amounts of the organoborane polyamine, B, F and K complexes to vary the level of boron in the adhesive composition from 0.015% to 0.24%. The compositions were prepared and tested for resistance to polishing stress using the techniques described above and with the results shown later in Table 6.

Table 6 Example 6 shows the effect on adhesion for low surface energy plastics when the boron level in the adhesive composition is varied.

The adhesive compositions according to the invention preferably include about 0.3 to 1.5% by weight of boron based on the total weight of the adhesive composition, more preferably about 0.04 to 1.0% by weight, most preferably about 100% by weight. 0.1 to 0.3% by weight. When the% by weight of boron is too low (ie, less than 0.3% by weight), minimal adhesion to low surface energy plastics is obtained. At high boron levels (eg, higher than those used in Example 6), the adhesion is still good but the adhesive becomes increasingly porous due to the release of borane and therefore, are less desirable.

Example 7 Example 7 describes the making of a pair of two-pair acrylic adhesives, known, "DP-805" which is commercially available from 3M Company (San Paul, MN), and an adhesive that was proposed to be based on the Patent. No. 4,536,546, Example 5 but using currently available materials (referred to herein as the "X" adhesive). The formulation of the adhesive X is as follows: Part A: 35.5 parts of HYPALON 30 (from E.I. duPont de Nemours) 53.2 parts of methyl methacrylate 9.8 parts of methacrylic acid 1 part of cumene hydroperoxide Part B: 25 parts of BLENDEX B467 (acrylonitrile-butadiene-styrene terpolymer from General Electric Specialty Chemicals, Parsburg, WV) 75 parts of methyl methacrylate 4,995 parts of VANAX 808 (from Vanderbilt Chemical Co.) 0.005 parts of the copper naphthenate solution.

Part A was generated by mixing the components until a viscous solution resulted. Part B was generated by first mixing the graft copolymer and methyl methacrylate until a bluish, stable dispersion resulted. VANAX 808 and copper naphthenate were added afterwards. Adhesive bonds were made and tested for polishing stress resistance as described in conjunction with Example 2 with the exception bonds were also made on 2024-T3 aluminum substrates according to the method described in ASTM D-1002. The results are shown later in Table 7.

Table 7 Table 7 shows that the two-part acrylic adhesive compositions according to the invention that include an effective amount of boron (as provided by the organoborane polyamine complexes of the invention) have excellent adhesion to low surface energy plastics, while other known two-part acrylic adhesives do not. However, known adhesives provide good adhesion to aluminum substrates. Known adhesives suffer from cohesive failure with aluminum substrates but fail adhesively with polymeric substrates. It will become apparent to those skilled in the art, various modifications and alterations of this invention, without departing from the scope and spirit of the invention. It should be understood that this invention is not limited to the illustrative embodiments set forth herein.

It is noted that in relation to this date, the best method known by the applicant to carry out the present 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 (43)

1. A complex comprising organoborane and polyoxyalkylene polyamine.

2. A complex according to claim 1, characterized in that the organoborane has the structure: wherein: R1 is an alkyl group having from 1 to 10 carbon atoms; and R2 and R3 are independently selected from alkyl groups having from 1 to 10 carbon atoms and groups containing phenyl.

3. A complex according to claim 1, characterized in that the polyoxyalkylene polyamine has a structure selected from the group consisting of: H2NR0- (R50) w- (R60) x- (R50) and -R4NH2 and [H2NR40- (R50) w] zR \ where: R4, R5 and R6 are alkylene groups having from 1 to 10 carbon atoms and which may be the same or may be different; R7 is the residue of a polyol; es = 1; x is = 0; and it is > 0; and z is > 2.

4. A polyamine organoborane complex, characterized in that it comprises organoborane and polyoxyalkylenepolyamine and has the structure: wherein: R1 is an alkyl group having from 1 to 10 carbon atoms; R2 and R3 are independently selected from alkyl groups having from 1 to 10 carbon atoms and groups containing phenyl; Am is polyoxyalkylene polyamine and has a structure selected from the group consisting of H2NR40- (R50) H- (R60) x- (R50) y-RNH2 and [H2NR40- (R50) w] z-R7, wherein: R4 , R5 and R6 are alkylene groups having 1 to 10 carbon atoms and which may be the same or which may be different; R7 is the residue of a polyol; the values of w, x and y are selected such that the organoborane polyamine complex is a liquid at room temperature; z is 3 or 4; and the value of v is selected to provide an effective ratio of nitrogen atoms to boron atoms in the complex.

5. An organoborane polyamine complex according to claim 4, characterized in that R1, R2 and R3 are independently selected from alkyl groups having from 1 to 5 carbon atoms.

6. An organoborane polyamine complex according to claim 5, characterized in that R1, R2 and R3 are the same.

7. An organoborane polyamine complex according to claim 4, characterized in that R4 is an alkyl group having from 2 to 4 carbon atoms, R5 is an alkyl group having 2 or 3 carbon atoms, and R6 is an alkyl group which It has 2 or 3 carbon atoms.

8. An organoborane polyamine complex according to claim 4, characterized in that the polyoxyalkylene polyamine has a molecular weight of less than about 5,000.

9. An organoborane polyamine complex according to claim 8, characterized in that the polyoxyalkylene polyamine has a molecular weight of about 250 to 1,000.

10. An organoborane polyamine complex according to claim 4, characterized in that the value of v is 0.1 to z.

11. An organoborane polyamine complex according to claim 4, characterized in that the ratio of nitrogen atoms to boron atoms of the complex is from about 1: 1 to 4: 1.

12. An organoborane polyamine complex according to claim 11, characterized in that the ratio of nitrogen atoms to boron atoms in the complex is about 1: 1.

13. A polyamine / characterized organoborane complex comprising organoborane and polyoxyalkylenepolyamine and having the structure: wherein: R1, R2 and R3 are alkyl groups having from 1 to 5 carbon atoms and are the same; Am is polyoxyalkylenepolyamine and has a structure selected from the group consisting of: H2NR0- (R50) w- (R60) x- (R50) and -R4NH2 and [H2NR0- (R50) w] z -R7, wherein: R 4 is an alkyl group having 2 to 4 carbon atoms; R5 is an alkyl group having 2 or 3 carbon atoms; R6 is an alkyl group having 2 or 3 carbon atoms; R7 is the residue of a polyol; the values of, x and y are selected such that the organoborane polyamine complex is a liquid at room temperature; z is 3 or 4; and the value of v is selected such that the reaction of nitrogen atoms to boron atoms in complexes of about 1: 1 to 2: 1.

14. A system capable of initiating the polymerization of an acrylic monomer, the system is characterized in that it comprises: a) a complex comprising organoborane and polyoxyalkylenepolyamine; and b) an effective amount of a compound that is reactive with the amine to release the organoborane.

15. A system according to claim 14, characterized in that the complex has the structure: wherein R1 is an alkyl group having from 1 to 10 carbon atoms; R2 and R3 are independently selected from alkyl groups having from 1 to 10 carbon atoms and groups containing phenyl; Am is polyoxyalkylene polyamine and has a structure selected from the group consisting of H2NR0- (R50) "- (R60) x- (R50) y-RNH2 and [H2NR40- (R50)"] 2-R7, wherein: R4, RD and R6 are alkylene groups having 1 to 10 carbon atoms and which may be the same or may be different; R7 is the residue of a polyol; w is > 1; x is > 0; and it is > 0; z is > 2; and the value of v is selected to provide an effective ratio of nitrogen atoms to boron atoms in the complex.

16. A system according to claim 15, characterized in that: R1, R2 and R3 are alkyl groups having from 1 to 5 carbon atoms and are the same; R 4 is an alkyl group having 2 to 4 carbon atoms; R5 is an alkyl group having 2 or 3 carbon atoms; R6 is an alkyl group having 2 or 3 carbon atoms; R7 is the residue of a polyol; the values of w, x and y are selected such that the organoborane polyamine complex is a liquid at room temperature; z is 3 or; and the value of v is selected such that the ratio of boron atoms to nitrogen atoms of the complex is from about 1: 1 to 2: 1.

17. A system according to claim 14, characterized in that the compound that is reactive with the amine is selected from the group consisting of isocyanate, acid, acid chloride, sulfonyl chloride and aldehyde.

18. A system according to claim 16, characterized in that the compound that is reactive with the amine is acrylic acid or methacrylic acid.

19. An acrylic, polymerizable composition, characterized in that it comprises: a) at least one acrylic monomer; b) an effective amount of a complex comprising organoborane and polyoxyalkylenepolyamine; and c) an effective amount of a compound that is reactive with the amine to release the organoborane to initiate the polymerization of at least one acrylic monomer.

20. An acrylic, polymerizable composition according to claim 19, characterized in that at least one acrylic monomer is selected from the group consisting of monofunctional acrylate ester, monofunctional methacrylate ester, substituted derivatives of the foregoing, and mixtures of the foregoing.

21. An acrylic composition, polymerizable according to claim 20, characterized in that the monofunctional methacrylate ester is selected from the group consisting of methyl methacrylate, ethyl methacrylate, methoxyethyl methacrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, methacrylate cyclohexyl, tetrahydrofurfuryl methacrylate, and mixtures thereof.

22. An acrylic, polymerizable composition according to claim 19, characterized in that at least one acrylic monomer comprises a mixture of alkyl methacrylate and alkyl acrylate.

23. An acrylic composition, polymerizable according to claim 22, characterized in that the alkyl methacrylate is methyl methacrylate and the alkyl acrylate is butyl acrylate.

24. An acrylic composition, polymerizable according to claim 19, characterized in that it comprises an elastomeric modifier.

24. An acrylic composition, polymerizable according to claim 19, characterized in that the composition comprises approximately 0.03 to 1.5% by weight of boron.

26. An acrylic, polymerizable composition according to claim 25, characterized in that the composition comprises about 0.1 to 0.3% by weight of boron.

27. An acrylic, polymerizable composition according to claim 19, characterized in that the compound that is reactive with the amine is selected from the group consisting of acid, isocyanate, acid chloride, sulfonyl chloride, and aldehyde.

28. An acrylic composition, polymerizable according to claim 19, characterized in that a complex has the structure: wherein: R1 is an alkyl group having from 1 to 10 carbon atoms; R2 and R3 are independently selected from alkyl groups having from 1 to 10 carbon atoms and groups containing phenyl; Am is polyoxyalkylenepolyamine and has a structure selected from the group consisting of: H2NR40- (R50) v- (R60) x- (R50) and -R4NH2 and [H2NR40- (R50) v] z -R7, wherein: R4, R5 and R6 are alkylene groups having from 1 to 10 carbon atoms and which may be the same or which may be different; R is the residue of a polyol; w is > 1 x is > 0 and it is > 0 z is > 2 the value of v is selected to provide an effective ratio of nitrogen atoms to boron atoms in the complex.

29. An acrylic composition, polymerizable according to claim 28, characterized in that the compound that is reactive with the amine is an acid.

30. A polymerizable composition according to claim 29, characterized in that the acid is a Lewis acid or a carboxylic acid.

31. An acrylic, polymerizable composition according to claim 28, characterized in that the amine-reactive compound is acrylic acid or methacrylic acid.

32. A composite article, characterized in that it comprises a first substrate and a second substrate joined to the first substrate by an adhesive, wherein the adhesive comprises the polymerized acrylic composition of claim 19.

33. A joined composite article according to claim 32, characterized in that the first substrate is a polymer of low surface energy.

34. A bonded composite article according to claim 33, characterized in that the first substrate is selected from the group consisting of polyethylene, polypropylene and polytetrafluoroethylene.

35. An acrylic, polymerizable composition, characterized in that it comprises: a) a mixture of acrylic monomers comprising alkyl acrylate monomer and an alkyl methacrylate monomer; b) an organoborane polyamine complex having the structure: wherein R1 is an alkyl group having from 1 to 10 carbon atoms; R2 and R3 are independently selected from alkyl groups having from 1 to 10 carbon atoms and groups containing phenyl; Am is polyoxyalkylene polyamine and has a structure selected from the group consisting of H2NR0- (R50) w- (R60) x- (R50) y-RNH2 and wherein: R4, R5 and R6 are alkylene groups having from 1 to 10 carbon atoms and which may be the same or may be different; R7 is the residue of a polyol; the values of w, x and y are selected such that the organoborane polyamine complex is a liquid at room temperature; z is 3 or 4; and the value of v is selected such that the ratio of nitrogen atoms to boron atoms in the complex is from about 1: 1 to 2: 1; and c) an effective amount of an acrylic acid or methacrylic acid to release the organoborane in the complex to initiate the polymerization of the acrylic monomer.

36. An acrylic composition, polymerizable according to claim 35, characterized in that it comprises approximately 0.03 to 1.5% by weight of boron.

37. An acrylic composition, polymerizable according to claim 36, characterized in that it comprises approximately 0.1 to 0.3% by weight of boron.

38. A composite article, characterized in that it comprises a first substrate and a second substrate joined to the first substrate by an adhesive, wherein the adhesive comprises the polymerized acrylic composition in claim 35.

39. A joined composite article according to claim 38, characterized in that the first substrate is a low surface energy polymer.

40. A joined composite article according to claim 39, characterized in that the first substrate is selected from the group consisting of polyethylene, polypropylene and polytetrafluoroethylene.

41. A joined composite article according to claim 40, characterized in that the second substrate is selected from the group consisting of polyethylene, polypropylene and polytetrafluoroethylene.

42. A method for initiating the polymerization of an acrylic monomer, the method is characterized in that it comprises the steps of: a) providing at least one acrylic monomer; b) mixing at least one acrylic monomer with a polymerization initiator system comprising: i) a complex comprising organoborane and polyoxyalkylenepolyamine; and ii) an effective amount of a compound that is reactive with amine to release the organoborane to initiate the polymerization and at least one acrylic monomer; and c) initiating the polymerization of at least one acrylic monomer.

43. A method for attaching a low surface energy polymer to a substrate, the method is characterized in that it comprises the steps of: a) providing a polymer having a surface energy of less than 45 mJ / m2; b) provide a substrate; c) providing an adhesive composition comprising: i) at least one acrylic monomer; ii) an effective amount of a complex comprising organoborane and polyoxyalkylenepolyamine; and iii) an effective amount of a compound that is reactive with amine to release the organoborane to initiate the polymerization of at least one acrylic monomer; d) applying the adhesive composition to either the low surface energy polymer or the substrate; e) attaching the low surface energy polymer and the substrate with the adhesive composition therebetween; and f) allowing the adhesive composition to cure to adhesively bond the low surface energy polymer and the substrate.