Methods for Forming Non-Environmentally Hazardous, Non-Volatile Adhesive Promoter Compositions for Curing Adhesives

US006001213A Ulllted States Patent [19] [11] Patent Number: 6,001,213 Liu [45] Date of Patent: *Dec. 14, 1999 [54] METHODS FOR FORMING NON- 4,869,772 9/1989 McDonnell et al. . ENVIRONMENTALLY HAZARDOUS, NON- 4,891,248 1/1990 Kraus. VOLATILE ADHESIVE PROMOTER 4933234 6/1990 K°beete1~~ COMPOSITIONS FOR CURING ADHESIVES 4979993 12/1990 0kam°‘° 6‘ a1~ ~ 5,066,743 11/1991 Okamoto et al. . [75] Inventor: Ju-Chao Liu, West Hartford, Conn. 5’079’098 1/1992 Liu ' 5,232,774 8/1993 Otsuka et al. ........................ .. 206/568 . _ _ 5,262,200 11/1993 Puder et al. . [73] Assignee: Loctite Corporation, Hartford, Conn. 5,314,562 5/1994 McDonnell et al. . [*1 Notice: This patent is Subject to a terminal diS_ 5,792,303 8/1998 Llu ........................................ .. 156/314 claimer. FOREIGN PATENT DOCUMENTS 624525 7/1961 Canada ................................ .. 156/314 [21] Appl. No.1 03/307,967 624525 8/1961 Canada . 0 220 555 10/1986 European Pat. Off. . 0 271 675 10/1987 European Pat. Off. . 0 295 930 B1 6 1988 E P . Off. . Related U.S. Application Data 33464 7;1973 Jzgfiféan at 33-162 10/1982 Japan. [22] Filed: Feb. 28, 1997 [60] Continuation of application No. 08/456,755, Jun. 1, 1995, which is a division of application No. 08/322,936, Oct. 13, OTHER PUBLIC ATIQNS 1994, Pat. No. 5,567,266. [51] Int. Cl.5 ...................................................... .. B32B 7/00 g1“’“f‘?“> Maékgvet 3: “P1‘?rf‘t’.‘ma‘}f’°NF1t‘.“dS1F‘§ C[1“"?‘1 [52] U.s. Cl. .................. .. 156/310; 106/287.24; 106/311; °a““‘.g an rymg. PP 1“ 1°“ 3 1°“ ‘’C r°.‘“" Packaging & Production Conference West 94 Anaheim, 156/314; 206/568 California Proceedings pp. 2197-2203 no apparent rel- [58] Field of Search ................................... .. 156/310, 314; ’ ’ CVEIHCC . 106/287.24, 311; 206/568 P’ E '—JhJ.G11h [561 References Cited afigif/Zyy, X 5fe"1I11lt:1e0rr F3n?_Ho§mai1 ‘Z LLP U.S. PATENT DOCUMENTS [57] ABSTRACT 2,784,127 3/1957 Joyner et al. . 3,260,637 7/1966 Von Emmet. A non-environmentally hazardous, non-volatile adhesive 3,266,625 8/1966 Hardman . promoter composition useful in promoting the cure and/or 3,336,377 9/1974 Ddahunty . enhancing adhesion of adhesives and for use in combination 4,042,442 8/1977 Dombroski et a1, , with adhesive bond polymerization. The promoter compo- 4,139,693 2/1979 Schoenberg . sition is a combination of a fluid carrier that remains 4,200,549 4/1980 Okamura et a1. . substantially present during the curing of an adhesive com- 4:377/190 3/1983 Shiraishi 6‘ 91~ ~ position and an active component capable of promoting the 4,444,933 4/1984 Columbus et al. . 4,450,265 5/1984 Harris . 4,460,759 7/1984 Robins . 4,496,685 1/1985 Nagasawa et al. . 4,822,426 4/1989 Ito et al. . 15 Claims, N0 Drawings cure and/or enhancing adhesion of the adhesive and being miscible in the fluid carrier. 6,001,213 1 METHODS FOR FORMING NON- ENVIRONMENTALLY HAZARDOUS, NON- VOLATILE ADHESIVE PROMOTER COMPOSITIONS FOR CURING ADHESIVES This is a continuation of Application No. 08/456,755 filed on Jun. 1, 1995, which is a divisional of Application No. 08/322,936 filed on Oct. 13, 1994, now U.S. Pat. No. 5,567,266. FIELD OF THE INVENTION This invention relates to a non-environmentally hazard- ous and non-volatile adhesive promoter composition for promoting the cure of adhesives and for use in combination with adhesive compositions. More particularly, the present invention relates to an adhesive promoter composition which includes a fluid carrier that remains substantially present during the curing of the adhesive composition and an adhesive promoter component capable of promoting the cure of the adhesive composition and being miscible in the fluid carrier. BACKGROUND OF THE INVENTION Chlorinated hydrocarbons such as 1,1,1-trichloroethane and chlorfluoro hydrocarbons (CFC), such as C2F3Cl3 also known as FREON®, have been used for many years as solvents in numerous applications. These materials have shown to be very useful in the preparation and delivery of activator and accelerator compositions used in the adhesive field. In recent years, the use of these compounds has been substantially lessened due to their deleterious effect on the environment. Regulations have been promulgated not only in the United States but in countries throughout the world to accelerate the phase-out of environmentally destructive solvents, and in particular those which are believed to be ozone-depleting substances. In addition to laws designed to prevent the use of these substances, product labelling requirements have also been promulgated to insure notice is given as to those compounds used as alternatives. Finding acceptable alternatives, however, has been an extremely difficult task. For example, in applications such as adhesive accelerator compositions, the solvent should possess high chemical stability, non-flammability, low toxicity, yet be sufficiently volatile to readily evaporate once applied to leave the active ingredient, e.g. an amine accelerator or activator, on the surface to which it is applied. In addition to these requirements, consideration must be given to cost factors which are critical to commercial development. Attempts to find good solvent systems which are non- ozone depleting, non-flammable, yet sufficiently volatile, have not been entirely successful. Although many materials have possessed certain of these characteristics, many have been deficient in the majority of these properties. For example, materials such as heptane, acetone, methylethyl ketone, isopropanol, and methanol are excellent solvent systems, with excellent volatility, i.e. low flash point tem- peratures and high vapor pressures, but are extremely flam- mable. Other substances such as isoparaffins, and propylene glycol ether are less flammable, but are still combustible and evaporate slower. In co-assigned and co-pending U.S. Application Ser. No. 08/322,937 filed concurrently herewith, one solution offered for the replacement of ozone-depleting CFC carriers in adhesive promoter compositions was a unique co-solvent composition comprising an azeotropic mixture of a perfluo- rocarbon compound and an alkylsiloxane. This co-solvent 10 15 20 25 30 35 40 45 50 55 60 65 2 solution was non-ozone depleting and possessed the required characteristics to be useful as a carrier for adhesive promoter compounds, including activators, accelerators, ini- tiators and the like for promoting cure or enhancing adhe- sion of cyanoacrylate adhesives. It is conventional in the art of adhesive promoters, i.e. accelerators, activators, initiators and the like, that they be carried in volatile solvents when used as separate compo- nents in conjunction with adhesive compositions. In the case of cyanoacrylate adhesives, accelerators are generally applied to a substrate surface prior to application of the adhesive. These adhesive promoter compositions, some- times also referred to as primer compositions, are usually comprised of amine compounds dissolved in a CFC solvent, or 1,1,1-trichloroethane, which as discussed above is no longer considered an environmentally safe material due to its ozone-depleting nature. Numerous patents describe the use of volatile solvents as carriers for adhesive promoter compositions, such as activators, accelerators and the like. Such adhesive promoter compositions are used in conjunction with the cure of cyanoacrylate adhesives, olefinic adhesives, anaerobic adhe- sives and two-part acrylic systems. For example, U.S. Pat. No. 3,260,637 describes a method of bonding a cyanoac- arylate adhesive using amines dissolved in a volatile carrier solvent preferably having a boiling point below about 100° C. U.S. Pat. No. 4,822,426 discloses a primer solution consisting of an organometallic compound combined with a fluorine-containing compound, for use with difficult to bond to non-polar resins, such as polyolefins. The primer com- position is applied with a volatile solvent. U.S. Pat. No. 3,836,377 discloses an adhesive composi- tion which consists of a monomeric ester of cyanoacetic acid and a polymerization accelerator which can be applied by means of a volatile solvent. U.S. Pat. No. 4,979,993 teaches the use of a primer composition consisting of a tertiary ammonium carboxylate compound carried by a low surface tension organic solvent. This reference also teaches that the solvent should readily evaporate to allow for the reaction of the primer with the adhesive. In two-part adhesive compositions, where a curable com- ponent is present in one part and a curing agent is present in a second part, the curing agent and/or accelerator is gener- ally applied with vehicles such as lower alcohols and in some cases water. For example, see U.S. Pat. No. 4,460,759, which teaches the removal of the solvent prior to bringing the surfaces together to initiate the bonding reaction. U.S. Pat. No. 4,933,234 discloses primed polymeric sub- strates having at least one organic nucleophilic graft- polymerizable monomer or salt thereof graffed thereon. Various amine-bearing monomers are disclosed and the monomer compositions may be applied using solvents, crosslinking agents and surfacts. Traditional cyanoacrylate adhesives have incorporated a variety of additives directly into the adhesive composition per se to strengthen the bond. These additives have conven- tionally been directly incorporated into the adhesive com- position and are not handled as a separate component, in contrast to typical accelerator and activator compositions. These additives, in the case of U.S. Pat. No. 4,139,693 included an adhesion promoter of the formula: 6,001,213 OH HO OH COOR' wherein R‘ is hydrogen or an alkyl, aryl or cycloalkyl group having 1 to 10 carbon atoms. The formal name given to this class of compounds is 3,4,5 -trihydroxybenzoic acid or esters thereof. In addition to the adhesion promoter, an inhibitor is also added to the cyanoacrylate adhesive composition to stabilize the mixture from prematurely curing. U.S. Pat. No. 2,784,127 discloses cyanoacrylate adhesive compositions which are plasticized by the addition of alkyl ester in aliphatic dicarboxylic acid of the formula, R1OOC—(CH2)n—COOR1 wherein n is a whole integer in the range of 1-8 and R1 is an alkyl group from 1 to 8 carbon atoms. Also disclosed are alkyl phosphates in which each alkyl group contains from 1 to 8 carbon atoms, as well as triaromatic phosphates such as triphenylphosphate and tricresyl-phosphate. These plasticizers are dissolved in the monomeric cyanoacrylate adhesive to prevent failure of the adhesive bond after aging. Up to about 20% of the plasti- cizers are disclosed as being incorporated. The plasticizers allegedly function to add flexibility to the bond without adversely affecting the degree of adhesion. No disclosure is given to the addition of a promoter component into the adhesive composition per se. As is evident from the discussion, the art is replete with examples of volatile solvents as carriers for adhesion pro- moter compositions. This is the case whether the adhesion promoter be an activator, accelerator, catalyst or initiator system. Solvents have not historically been welcome in the bonding process since they weaken the adhesive bond, interfere with the adhesive bonding process, prevent contact between the adhesive and the substrate and in some instances, attack the adhesive and/or the substrate. The present inventor has discovered that using a fluid carrier other than a volatile solvent to dissolve an adhesion promoter component, carry it to the substrate and incorpo- rate itself into the adhesive composition during bonding, alleviates these difliculties. Thus, rather than approach the environmental problem of ozone depletion using a non- ozone depleting volatile solvent, the present invention uti- lizes a substantially non-volatile fluid carrier which is mis- cible in the promoter, delivers the promoter component to the substrate surface and remains incorporated in the adhe- sive. It is clear that there is a need for such a non-volatile, non-ozone depleting fluid carrier which is capable of suffi- ciently carrying the adhesive promoter component to the substrate surface, as well as being incorporated into the adhesive composition during the bonding process without interfering with polymerization. SUMMARY OF THE INVENTION The present invention is directed to an adhesive promoter composition for promoting the cure and/or enhancing the adhesion of adhesive compositions that includes a fluid carrier, which remains substantially present during the cure of the adhesive composition, and an adhesive promoter component being miscible in said fluid carrier and being capable of promoting the cure of the adhesive composition. 10 15 20 25 30 35 40 45 50 55 60 65 4 The fluid carrier of the adhesive promoter composition is substantially non-volatile and remains incorporated in the adhesive composition during cure. The adhesive promoter component can be any active ingredient that is used to prepare a surface for bonding or to promote the curing of the adhesive in the bonding process. For purposes of this invention, the term “active” will mean the adhesive pro- moter component. The active component is combined with the non-volatile fluid carrier to comprise the adhesive pro- moter composition. For example, in a preferred embodiment of the present invention, the adhesive promoter component is typically an amine or amino-bearing compound used to cure cyanoacrylate adhesive compositions. Other examples include organometallic compounds used as primers for anaerobic adhesive compositions. As previously described, activator compositions typically used in conjunction with these types of adhesive composi- tions employ volatile solvents to carry the activator com- ponent to the substrate surface. The present invention clearly represents a departure from solvent carriers which served only to transport the active and were subsequently removed or flashed-off prior to contacting the adhesive composition. Rather, the present invention employs a non-volatile fluid carrier which participates not only by transporting the adhe- sive promoter component, but also by further serving to plasticize the adhesive composition during cure. In a pre- ferred embodiment, the fluid carrier has at least one unsat- urated molecular bond present to overcome the tendency of certain saturated esters from attacking particular plastic substrates. The non-volatile fluid carrier is generally an ester having a boiling point about 100° C. or more and which is fluid at room temperature. DETAILED DESCRIPTION AND PREFERRED EMBODIMENTS Adhesive promoter compositions of the present invention provide a novel approach to the curing of adhesive compo- sitions in adhesive bonding. The promoter composition includes a substantially non-volatile fluid carrier that remains present during the curing of an adhesive composi- tion and an adhesive promoter component being miscible in the fluid carrier and being capable of promoting the cure and/or enhancing the adhesion of an adhesive composition. Rather than functioning like conventional volatile solvents, as temporary carriers which are intended to evaporate once the activator component is deposited, the fluid carrier of the present invention is incorporated into the adhesive compo- sition. Thus, whereas conventional solvents negatively affected the cure and bonding of adhesives to substrates, the present compositions contribute in a positive way to the overall properties of the adhesive. These effects are in addition to the environmental advantages obtained because (the fluid carrier does not evaporate) or cause undesirable waste product. For purposes of this invention, the term “promoter com- position” is meant to be interpreted in the broadest sense as including accelerating, activating, initiating and other adhe- sive promoting compositions which may be used in two part systems and applied to the surface of a substrate prior to contacting the substrate with an adhesive. Also for purposes of this invention, the term “non-volatile” will mean that the boiling point of the ester is about 100° C. or greater. Although the function of the fluid carrier once incorpo- rated into the adhesive composition is not fully understood, and without wishing to be bound by any one theory, it is 6,001,213 5 believed that the fluid carrier serves to plasticize the adhe- sive. The fluid carrier thus serves as a useful additive in the adhesive composition, in addition to serving its primary purpose of transporting the adhesive promoter component onto the substrate. More specifically, the non-volatile fluid carrier may be selected from the group consisting of esters which have a boiling point of about 100° C. or greater and which are fluid at room temperature. These esters may be formed from the reaction of alkyl or aromatic carboxylic acids with alkyl or aromatic alcohols. Other methods of preparing esters useful in the present invention are also contemplated. More specifically, the fluid carrier is preferably selected from the group consisting of an acetic ester of a C3—C18 alkyl alcohol, an acetic ester of a C2—C18 alkenyl or aryl alcohol, an acetic ester a C3—C18 allyl alcohol, an acetic ester of a C7—C18 alkaryl alcohol, an acetic ester of a C7—C18 aryalkyl alcohol and mixtures thereof. The aforementioned esters are par- ticularly useful due to their commercial availability and ease of use. Other useful non-volatile fluid carriers contemplated within the scope of the present invention include those formed from the reaction of aromatic carboxylic acids, such as phthalic acid, with alkyl alcohols. Diethyl phthalate, dipropyl phthalate, dibutyl phthalate and dioctyl phthalate are typical examples of these. Other useful esters include esters of aromatic alcohols with alkyl carboxylic acids, such as linalyl acetate, and phenethyl acetate. The fluid carrier may also be a benzoic diester of an alkyl glycol of the formula: OH—(CXHBO),,—H wherein X is 2-3 and n may be 1 up to about 10, provided the glycol remains fluid at about room temperature. Non- limiting examples include ethylene glycol dibenzoate, dieth- ylene glycol dibenzoate, propylene glycol dibenzoate, dipro- pylene glycol dibenzoate and mixtures thereof. In addition, the fluid carrier may also be an acetic ester of phenol. It is preferred that the fluid carrier have at least one unsaturated bond present. This is to prevent the tendency of saturated esters to attack certain plastic substrates. It has been found that when unsaturated bonds are present, this tendency is alleviated. Since plastic substrates are a primary bonding surface for many adhesives, particularly cyanoacry- late adhesives, this feature is important in these applications. The active component of the promoter compositions may be selected from a wide variety of adhesive promoter compounds and materials. The particular promoter compo- nent will, of course, depend on the adhesive composition to be employed and the function of the component, as well as the type of substrate to be bonded. Cyanoacrylates, anaerobics, acrylics, epoxies and olefins each have classes of compounds which activate, accelerate or otherwise promote their cure and/or enhance adhesion. The fluid non-volatile carriers of the present invention have been found to be particularly useful with activator compounds for use with cyanoacrylate adhesive composi- tions. Cyanoacrylate adhesives are rapid setting materials which have excellent utility in bonding a variety of mate- rials. The polymerization of cyanoacrylate adhesives is catalyzed using anionic materials such as hydroxyl- or amine-containing compounds. In the present invention, these compounds can be selected from a wide variety of materials which include: 10 15 20 25 30 35 40 45 50 55 60 65 6 a) organic or inorganic substituted and unsubstituted amines such as primary, secondary and tertiary amines and their salts; b) N-substituted alkanoamines; c) acylated N-substituted alkanoamines; d) polyamines, such as diamines; e) heterocyclic amines such as the diazabicyclo or triaz- abicyclo compounds disclosed in U.S. Pat. No. 4,869, 772 and having the formulas: (1) (11) (III) J\ N N N f) tertiary ammonium carboxylate compounds disclosed in U.S. Pat. No. 5,066,743 and having the formula: T1 {R3—N—R2}+ R4Coo— H wherein R1, R2, R3 and R4 may each vary indepen- dently of each other and may be selected from the group consisting of alkyl, alkenyl, alkynyl, alkylaryl and arylalkyl, and preferably wherein at least one of R1, R2 and R3 is a long chain alkyl moiety having 6-20 carbon atoms and R4 is selected from the group con- sisting of alkyl and alkenyl; g) phosphazene compounds including ring or chain poly- mers containing alternating phosphorus and nitrogen atoms, such as disclosed in U.S. Pat. No. 4,496, 686; h) ethylenediamine compounds such as those disclosed in U.S. Pat. No. 5,314,562 and having the formula: R5 R5 \ / N— CH2—CH2—N\ R5 R5 wherein each R5, which may be the same or different, represents hydrogen, an alkyl, alkenyl or alkoxy group having 1 to 8 carbon atoms, an aryl group having 6 to 8 carbon atoms, a nitrogen-, silicon- or silicon- substituted group having 1 to 8 carbon atoms or a heterocyclic group having up to 8 carbon atoms which may be unsubstituted or substituted with hydroxy, ether oxygen or sulphur; i) quaternary ammonium compounds useful as primers for improving the adhesion, as disclosed in U.S. Pat. No. 5,079,098, having the formula: 6,001,213 7 R1 I e ea R4—1|~I—R2 A $ R3 wherein R1, R2, R3, and R4 may each vary indepen- dently of the others and are selected from the group consisting of alkyl, hydroxyalkyl, aryl, alkaryl, aralkyl and alkenyl, optionally substituted with heteroatoms; and A— is an anion whose pKa value in deprotonation equilibrium reaction is greater than about 0. Among the preferred class of amines are the acylated N-substituted alkanoamines such as dimethyl-para-toluidine (DMPT). DMPT has been found to be particularly useful in the present invention as the activator component to promote the cure of cyanoacrylate adhesives. Generally, the promoter component, i.e. active component, is present in the adhesive promoter composition in amounts which are effective to produce the required cure speed and tensile strength. The active component of the present invention may be present in amounts of about 0.1% to about 10% by weight of the activator composition. Preferably, the activator component is present in the com- position in amounts of about 0.5% to about 5.0% and most preferably, about 0.5% to about 1.0% by weight. It is preferred to apply the adhesive promoter composition at the lowest effective concentration to decrease cost and increase ease of application, as well as allow the active to be close to the thickness of a monomolecular layer. Typically, one application of the activator composition on one side of the substrate is sufficient, but multiple coatings may of course be applied. In addition to the fluid carrier and active component, the adhesive promoter composition may contain other materials and conventional additives useful in adhesive promoter compositions. These include, without limitation, stabilizers, viscosity modifiers, odor-masking agents, coloring agents and the like. The activator compositions of the present invention can be used on numerous types of bonding surfaces, such as steel, plastic, glass and wood. These compositions provide a more environmentally-friendly alternative to conventional solvent-containing adhesive promoter compositions, and do not attack most engineering plastics. Additionally, they are non-ozone depleting, non-flammable and non-combustible. The adhesive promoter compositions of the present inven- tion may be applied to the substrate to be bonded in any manner that is satisfactory to enhance cure speed and/or adhesion of the cyanoacrylate bondant to the substrate. For example, spraying, dipping, brushing, swabbing, wiping, roller-coating, etc. of the activator composition onto one or more of the substrate surfaces prior to application of the adhesive is preferred. The thickness of the adhesive promoter composition and adhesive layer may vary widely, depending on the character and composition of the substrate surfaces, the particular adhesive and active to be employed, as well as the end use of the final bonded assembly. With any given set of parameters, acceptable and optimum thicknesses may be determined by lapshear tensile strength values for particular samples at various primer and adhesive layer thicknesses. The adhesive layer of about “0” to about 5 mils and as great as about 10 mils have been found to be generally satisfactory for most substrates. Those plastic materials with which the adhesive promoter compositions have been shown to be effective include, 10 15 20 25 30 35 40 45 50 55 60 65 8 without limitation, polycarbonate, polyphenylene ether alloy, polyphenylene sulfide, polyphenylene oxide, nylon, melamine, polyacetal, polycarbonate, polyesters, acrylic, acrylonitrile butadiene styrene (ABS), cellulose acetate, ethylene, vinyl, acetate (EVA) ionomer, polyarulether, polyethylene, polypropylene, polybutylene, polyallomer, polymethylpentane, polystyrene, polysulfone, polyvinyl chloride (PVC), styrene acrylonitrile (SAN), styrene butadiene, epoxides and phenolics, among others. Suitable cyanoacrylate adhesives for use with the present invention are represented by the general formula: CH2=C—CooR5 CN wherein R6 is alkyl, alkenyl, cycloalkyl, aryl, alkoxalkyl, aralkyl, haloalkyl or other suitable group. The lower alkyl alpha-cyanoacrylates are preferred. In particular, these include methyl, ethyl, n-propyl, n-butyl, isobutyl, isopropyl, allyl, cyclohexyl, methoxyethyl, methoxypropyl, cyclohexyl, n-pentyl, allyl, and ethoxyethyl cyanoacrylates. In applications where structural engineering adhesives are employed such as anaerobic adhesives, the adhesive pro- moter compositions may contain components which interact with the initiator present in the adhesive composition to further speed the cure. For example, tertiary alkyl amines, rhodamine, organic hydrazides, alkoxy amines, as well as organometallic compounds such as ferrocene, are conven- tionally used. The present invention also contemplates a method of bonding substrate surfaces together with an adhesive com- position. This method includes treating a surface of at least one substrate with an adhesive promoter composition which includes a fluid carrier that remains present during the cure of said adhesive composition and an adhesive promoter, i.e. active, component which is capable of promoting the cure or enhancing adhesion of said adhesive composition and is miscible in said fluid carrier. Subsequent to treatment of the substrate surface with the adhesive promoter composition, an adhesive composition is applied to at least one of the substrate surfaces, either the treated surface or the non- treated surface, and bonding of the substrate surfaces is effectuated by placing them in contact with each other and permitting polymerization to occur. In another aspect of the present invention, an adhesive kit comprises two parts co-located in a single package whereby the first part includes an adhesive promoter composition comprising a fluid carrier which remains present during the cure of an adhesive composition and a promoter component which is miscible in said fluid carrier and promotes the cure and/or adhesion of said adhesive composition; and a second part which includes an adhesive composition, the cure of which is promoted by said adhesive promoter composition. The features and advantages of the present invention will be more clearly understood by reference to the following examples, which are illustrative of certain preferred embodiments, but are not to be construed as limiting the scope of the present invention. EXAMPLES Adhesive promoter compositions of the present invention, as well as control compositions, were formulated as shown 6,001,213 9 in Table 1, below. Compositions 1-14 represent activator compositions which use the non-volatile fluid carrier of the present invention. TABLE 1 ADHESIVE PROMOTER COMPOSITIONS Active Component (% weight) Adhesive Type Activator Non-volatile ’uid Composition carrier 1 dipropylene g ycol 0.2 BBTS e 1y cyanoacry a e dibenzoate (rub aer con aining) 2 dipropylene g ycol 0.2 BBTS e 1y cyanoacry a e dibenzoate (ge wi 1 si ica) 3 dipropylene g ycol 0.4 BBTS e 1y cyanoacry a e dibenzoate (rub aer con aining) 4 dipropylene g ycol 0.4 BBTS e 1y cyanoacry a e dibenzoate (ge wi 1 si ica) 5 dipropylene g ycol 0.5 BBTS e 1y cyanoacry a e dibenzoate (ge wi 1 si ica) 6 dipropylene g ycol 0.5 BBTS e 1y cyanoacry a e dibenzoate (wi 1 1ic < OO \I >< >< >< >< >< >< O>< NO O>< >< >< >< >< OOOOO>< X indicates the fluid had no visible effect on plastic 0 indicates the fluid had a visible effect on plastic, with clouding, etching or crazing *Trademark The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention and all such modifications are intended to be included within the scope of the following claims. What is claimed is: 1. A method of bonding substrate surfaces with an adhe- sive composition comprising: treating a surface of at least one of said substrate surfaces with an adhesive promoter composition comprising a carrier which remains fluid at room temperature and present during the cure of said adhesive composition, said carrier being selected from the group consisting of acetic esters, benzoic diesters and phthalic esters and having at least one unsaturated bond present, and an adhesive promoter component which is capable of promoting the cure and/or enhancing adhesion of said adhesive composition and is miscible in said carrier; applying an adhesive composition to the surface of at least one of the substrates; and incorporating said carrier into said adhesive composition by placing said substrate surfaces in Contact with each other to prevent release or said carrier from said adhe- sive composition and to bond said substrate surfaces together. 2. The method of claim 1 wherein the fluid carrier is selected from the group consisting of an acetic ester of 10 15 20 25 30 35 40 45 50 55 60 12 C2—C18 alkenyl or aryl alcohol, an acetic ester of C3—C18 allyl alcohols, an acetic ester of C7—C18 alkylaryl alcohol, an acetic ester of C7—C18 arylalkyl alcohol and mixtures thereof. 3. The method of claim 1 wherein the fluid carrier is selected from the group consisting of linalyl acetate, diethyl phthalate, dipropyl phthalate, dibutyl phthalate, dioctyl phthalate, phenethyl acetate and mixtures thereof. 4. The method of claim 1 wherein the fluid carrier is a benzoic diester of an alkyl glycol. 5. The method of claim 4 wherein the fluid carrier is selected from the group consisting of ethylene glycol dibenzoate, diethylene glycol dibenzoate, propylene glycol dibenzoate, dibenzoate, dipropylene glycol dibenzoate and mixtures thereof. 6. The method of claim 1 wherein the adhesive promoter component is a base. 7. The method of claim 6 wherein the adhesive promoter component is an amine-containing compound. 8. The method of claim 7 wherein the amine-containing compound is selected from the group consisting of N,N- dimethyl-p-toluidine, t-butyl-2-benzothiazolesulfenamide, N-oxydiethylene benzothiazole-2-sulfenamide, 2,2'-(p- tolylimino) diethanol (hydroxyethyl-p-toluidine) and mix- tures thereof. 9. The method of claim 8 wherein the amine-containing compound is present in amounts of about 0.01% to about 10% by weight. 10. The method of claim 9 wherein the amine-containing compound is present in amounts of about 0.5% to about 10% by weight. 11. The method of claim 1 wherein said adhesive pro- moter component is an organometallic substance. 12. A method of bonding substrate surfaces comprising: a) forming a curable layer between said substrate surfaces, said curable layer including an adhesive composi- tion; and (ii) an adhesive promoter composition which includes an adhesive promoter component and a carrier for said adhesive promoter component, said carrier being selected from the group consisting or acetic esters, benzoic diesters and phthalic esters and having at least one unsaturated bond present, said carrier being a plasticizer for said adhesive composition and being fluid at room temperature; and b) curing said curable layer between said substrates, whereby said adhesive promoter composition is incor- porated into said adhesive composition to plasticize and promote cure of said adhesive composition and to prevent release of said carrier from said adhesive composition. 13. The method of claim 12 wherein said carrier is selected from the group consisting of an acetic ester of C3-C1 8 alkyl alcohol, an acetic ester of C3—C18 allyl alcohol, an acetic ester of C7-C1 8 alkylaryl alcohol, an acetic ester of C7—C18 arylalkyl alcohol and mixtures thereof. 14. The method of claim 12 wherein said carrier is selected from the group consisting of linalyl acetate, diethyl phthalate, dipropyl phthalate, dibutyl phthalate, dioctyl phthalate, phenethyl acetate and mixtures thereof. 15. The method of claim 12 wherein said carrier is a benzoic diester of an alkyl glycol having the formula OH— (CxH2xO)n—H wherein x is 2-3 and n may be 1-10 provided the glycol remains fluid at room temperature. * * * * * UNITED STATES PATENT AND TRADEMARK OFFICE CERTIFICATE OF CORRECTION PATENT NO. 5,901,213 DATED December 14, 1999 INVENTOR(S) : Ju-Chao Liu It is certified that error appears in the above-identified patent and that said Letters Patent is hereby corrected as shown below: At column 1, line 6, the printed patent incorrectly reads "This is a continuation ofApplication No...."; the patent should read --This is a continuation of copending Application No...--. Signed and Sealed this Twelfth Day of December, 2000 Q. TODD DICKINSON Arresting Ofiicer Director of Parents and Trademark: