Stabilized cyanoacrylate compositions

Abstract

This invention relates to cyanoacrylate-containing compositions that include, in addition to the cyanoacrylate component, a benzodioxol free radical stabilizer. The inventive cyanoacrylate compositions demonstrate improved shelf life stability while maintaining the level of adhesive performance.

Description

STABILIZED CYANOACRYLATE COMPOSITIONSBACKGROUND1. Field

[0001] This invention relates to cyanoacrylate-containing compositions that include, in addition to the cyanoacrylate component, a benzodioxol free radical stabilizer. The inventive cyanoacrylate compositions demonstrate improved shelf life stability while maintaining the level of adhesive performance.2. Brief Description of Related Technology

[0002] Cyanoacrylate adhesive compositions are well known, and widely used as quick setting, instant adhesives with a wide variety of uses. See H. V. Coover, D. W. Dreifus and J. T. O'Connor, “Cyanoacrylate Adhesives” in Handbook of Adhesives, 27, 463-77, I. Skeist, ed., Van Nostrand Reinhold, New York, 3rd ed. (1990). See also G. H. Millet, “Cyanoacrylate Adhesives” in Structural Adhesives: Chemistry and Technology, S. R. Hartshorn, ed., Pienun Press, New York, p. 249-307 (1986).

[0003] Because of the sensitive nature of cyanoacrylate compositions, the cyanoacrylate monomers and the cyanoacrylate compositions must be stabilized against premature reaction, preventing viscosity increase. Viscosity increases over time can render the cyanoacrylate composition ineffective as an adhesive.

[0004] Free radical stabilizers and / or anionic stabilizers have long been used to prolong the shelf life of cyanoacrylate compositions.

[0005] In the context of medical grade cyanoacrylates, U.S. Patent No. 5,530,037 (McDonnell) speaks to the use of certain stabilizers (though not hydroquinone; HQ) that provide benefit after the cyanoacrylate has been sterilized through exposure to gamma irradiation. Those certain stabilizer include butylated hydroxyanisole (BHA) which is a blend of isomers (2-tert-butyl-4-methoxy phenol and 3-tert-butyl-4-methoxy phenol) and butylated hydroxytoluene (BHT).

[0006] Some free radical stabilizers have in recent years come under regulatory scrutiny from various regulatory bodies. One such free radical stabilizer is hydroquinone. Accordingly, much energy has been expended to identify and evaluatealternative free radical stabilizers to hydroquinone that function to extend the shelf life of cyanoacrylate compositions while not contributing to any deleterious effect on the cyanoacrylate composition.

[0007] Notwithstanding the state of the art and the efforts to date to identify and evaluate any such alternatives for stabilizing cyanoacrylate compositions, there remains a long felt, yet unmet, need to provide such alternatives as free radical stabilizer, particularly without compromising other physical and / or functional properties of the resulting cyanoacrylate composition. That need has been outstanding until now.SUMMARY

[0008] Cyanoacrylate compositions, which include beyond the cyanoacrylate component, a benzodioxol free radical stabilizer, are thus provided. Cyanoacrylate compositions of the invention are curable adhesive compositions.

[0009] The inclusion of the benzodioxol free radical stabilizer provides for shelf life stability properties commensurate with the well-known stabilizer, hydroquinone (HQ), but without the more extreme regulatory labelling requirements, as is shown in the Examples.

[0010] The benzodioxol free radical stabilizer may be represented by the following structure:wherein R1 , R2, R3, R4 , R5, and R6 are independently selected from H, OH, linear or branched C1-C6 alkyl, linear or branched C1-C6 alkoxy, linear or branched C2-C6 alkenyl, linear or branched C2-C6 alkynyl, C5-C9 aryl, C3-C9 cycloalkyl, C4-C9 cycloalkenyl, C4-C9 cycloalkynyl, C5-C9 heteroaryl, C3-C9 heteroalicyclyl, C6-C12aralkyl, C6-C12 heteroaralkyl, C6-C12 (heteroalicyclyl)alkyl, C2-C6 alkoxy, C5-C9 aryloxy, C2-C6 acyl, carboxyl, C1-C6 ester, mercapto, C1-C6 alkylthio, C5-C9 arylthio, cyano, halogen, C1-C6 carbonyl, C1 -C6 ketone, C1-C6 thiocarbonyl, O-carbamyl, N- carbamyl, O-thiocarbamyl, N-thiocarbamyl, C-amido, N-amido, S-sulfonamido, N- sulfonamido, C-carboxy, O-carboxy, isocyanato, thiocyanato, isothiocyanato, nitro, silyl, C1-C6 sulfenyl, sulfinyl, sulfonyl, C1-C6 haloalkyl, C1-C6 haloalkoxy, trihalomethanesulfonyl, trihalomethanesulfonamido or combinations thereof, and R5 and R6 when present may be connected by an C1-C6 alkyl, C1-C6 alkoxy, C2-C6 alkenyl, C2-C6 alkynyl, C5-C9 heteroaryl, or C1-C6 heteroalkyl linkage;A is selected from C, N, S or 0, provided that when A is 0 or S, R5 or R6 will not be present; when A is N, only R5 or R6 will be present; and when A is C, both R5 and R6 will be present, within which are the following two subgeneric structures:wherein R1 , R2, R3, R4 , R5, and R6 are independently selected from H, OH, linear or branched C1 -C6 alkyl, linear or branched C1 -C6 alkoxy, linear or branched C2-C6 alkenyl, linear or branched C2-C6 alkynyl, C5-C9 aryl, C3-C9 cycloalkyl, C4-C9 cycloalkenyl, C4-C9 cycloalkynyl, C5-C9 heteroaryl, C3-C9 heteroalicyclyl, C6-C12 aralkyl, C6-C12 heteroaralkyl, C6-C12 (heteroalicyclyl)alkyl, C2-C6 alkoxy, C5-C9 aryloxy, C2-C6 acyl, carboxyl, C1-C6 ester, mercapto, C1-C6 alkylthio, C5-C9 arylthio, cyano, halogen, C1-C6 carbonyl, C1 -C6 ketone, C1-C6 thiocarbonyl, O-carbamyl, N- carbamyl, O-thiocarbamyl, N-thiocarbamyl, C-amido, N-amido, S-sulfonamido, N- sulfonamido, C-carboxy, O-carboxy, isocyanato, thiocyanato, isothiocyanato, nitro, silyl, C1-C6 sulfenyl, sulfinyl, sulfonyl, C1-C6 haloalkyl, C1-C6 haloalkoxy, trihalomethanesulfonyl, trihalomethanesulfonamido or combinations thereof, andC wherein R1 , R2, R3, R4 , R5, and R6 are independently selected from H, OH, linear or branched C1 -C6 alkyl, linear or branched C1 -C6 alkoxy, linear or branched C2-C6 alkenyl, linear or branched C2-C6 alkynyl, C5-C9 aryl, C3-C9 cycloalkyl, C4-C9 cycloalkenyl, C4-C9 cycloalkynyl, C5-C9 heteroaryl, C3-C9 heteroalicyclyl, C6-C12 aralkyl, C6-C12 heteroaralkyl, C6-C12 (heteroalicyclyl)alkyl, C2-C6 alkoxy, C5-C9 aryloxy, C2-C6 acyl, carboxyl, C1-C6 ester, mercapto, C1-C6 alkylthio, C5-C9 arylthio, cyano, halogen, C1-C6 carbonyl, C1 -C6 ketone, C1-C6 thiocarbonyl, O-carbamyl, N- carbamyl, O-thiocarbamyl, N-thiocarbamyl, C-amido, N-amido, S-sulfonamido, N- sulfonamido, C-carboxy, O-carboxy, isocyanato, thiocyanato, isothiocyanato, nitro, silyl, C1-C6 sulfenyl, sulfinyl, sulfonyl, C1-C6 haloalkyl, C1-C6 haloalkoxy, trihalomethanesulfonyl, trihalomethanesulfonamido or combinations thereof, and R5 and R6 when present may be connected by an C1-C6 alkyl, C1-C6 alkoxy, C2-C6 alkenyl, C2-C6 alkynyl, C5-C9 heteroaryl, or C1-C6 heteroalkyl linkage;A is selected from C, N, S or 0, provided that when A is 0 or S, R5 or R6 will not be present; when A is N, only R5 or R6 will be present; and when A is C, both R5 and R6 will be present.

[0011] This invention is also directed to a method of bonding together two substrates, which method includes applying to at least one of the substrates a composition as described above, and thereafter mating together the substrates.

[0012] In addition, the present invention is directed to reaction products of the inventive compositions.

[0013] The invention will be more fully understood by a reading of the section entitled “Detailed Description”, which follows.DETAILED DESCRIPTION

[0014] As noted above, this invention is directed to a cyanoacrylate composition, which includes beyond the cyanoacrylate component, a benzodioxol free radical stabilizer.

[0015] The cyanoacrylate component includes cyanoacrylate monomers which may be chosen with a raft of substituents, such as those represented by H2C=C(CN) — COOR, where R is selected from C1-15 alkyl, C2-15 alkoxyalkyl, C3-15 cycloalkyl, C2- 15 alkenyl, C5-15 aralkyl, Cs-is aryl, C2-15 allyl and C1-15 haloalkyl groups. Desirably, the cyanoacrylate monomer is selected from methyl cyanoacrylate, ethyl-2-cyanoacrylate, propyl cyanoacrylates, butyl cyanoacrylates (such as n-butyl-2-cyanoacrylate), octyl cyanoacrylates, allyl cyanoacrylate, p-methoxyethyl cyanoacrylate and combinations thereof. A particularly desirable one is p-methoxyethyl cyanoacrylate.

[0016] The cyanoacrylate component should be included in the compositions in an amount within the range of from about 50% to about 99.98% by weight, with the range of about 90% to about 99% by weight being desirable, and about 95% by weight of the total composition being particularly desirable.

[0017] A stabilizer package is also ordinarily found in cyanoacrylate compositions. The stabilizer package may include one or more free radical stabilizers and anionic stabilizers, each of the identity and amount of which are well known to those of ordinary skill in the art. See e.g. U.S. Patent Nos. 5,530,037 and 6,607,632, the disclosures of each of which are hereby incorporated herein by reference.

[0018] Here however the free radical stabilizer is a benzodioxol. Examples of the benzodioxol include those represented by the following structure A:wherein R1 , R2, R3, R4 , R5, and R6 are independently selected from H, OH, linear or branched C1 -C6 alkyl, linear or branched C1 -C6 alkoxy, linear or branched C2-C6 alkenyl, linear or branched C2-C6 alkynyl, C5-C9 aryl, C3-C9 cycloalkyl, C4-C9 cycloalkenyl, C4-C9 cycloalkynyl, C5-C9 heteroaryl, C3-C9 heteroalicyclyl, C6-C12 aralkyl, C6-C12 heteroaralkyl, C6-C12 (heteroalicyclyl)alkyl, C2-C6 alkoxy, C5-C9 aryloxy, C2-C6 acyl, carboxyl, C1-C6 ester, mercapto, C1-C6 alkylthio, C5-C9 arylthio, cyano, halogen, C1-C6 carbonyl, C1 -C6 ketone, C1-C6 thiocarbonyl, O-carbamyl, N- carbamyl, O-thiocarbamyl, N-thiocarbamyl, C-amido, N-amido, S-sulfonamido, N- sulfonamido, C-carboxy, O-carboxy, isocyanato, thiocyanato, isothiocyanato, nitro, silyl, C1-C6 sulfenyl, sulfinyl, sulfonyl, C1-C6 haloalkyl, C1-C6 haloalkoxy, trihalomethanesulfonyl, trihalomethanesulfonamido or combinations thereof, and R5 and R6 when present may be connected by an C1-C6 alkyl, C1-C6 alkoxy, C2-C6 alkenyl, C2-C6 alkynyl, C5-C9 heteroaryl, or C1-C6 heteroalkyl linkage;A is selected from C, N, S or 0, provided that when A is 0 or S, R5 or R6 will not be present; when A is N, only R5 or R6 will be present; and when A is C, both R5 and R6 will be present.

[0019] More specific embodiments within structure A are:wherein R1 , R2, R3, R4 , R5, and R6 are independently selected from H, OH, linear or branched C1 -C6 alkyl, linear or branched C1 -C6 alkoxy, linear or branched C2-C6 alkenyl, linear or branched C2-C6 alkynyl, C5-C9 aryl, C3-C9 cycloalkyl, C4-C9 cycloalkenyl, C4-C9 cycloalkynyl, C5-C9 heteroaryl, C3-C9 heteroalicyclyl, C6-C12 aralkyl, C6-C12 heteroaralkyl, C6-C12 (heteroalicyclyl)alkyl, C2-C6 alkoxy, C5-C9 aryloxy, C2-C6 acyl, carboxyl, C1-C6 ester, mercapto, C1-C6 alkylthio, C5-C9 arylthio, cyano, halogen, C1-C6 carbonyl, C1 -C6 ketone, C1-C6 thiocarbonyl, O-carbamyl, N- carbamyl, O-thiocarbamyl, N-thiocarbamyl, C-amido, N-amido, S-sulfonamido, N-sulfonamido, C-carboxy, O-carboxy, isocyanato, thiocyanato, isothiocyanato, nitro, silyl, C1-C6 sulfenyl, sulfinyl, sulfonyl, C1-C6 haloalkyl, C1-C6 haloalkoxy, trihalomethanesulfonyl, trihalomethanesulfonamido or combinations thereof, andwherein R1 , R2, R3, R4 , R5, and R6 are independently selected from H, OH, linear or branched C1 -C6 alkyl, linear or branched C1 -C6 alkoxy, linear or branched C2-C6 alkenyl, linear or branched C2-C6 alkynyl, C5-C9 aryl, C3-C9 cycloalkyl, C4-C9 cycloalkenyl, C4-C9 cycloalkynyl, C5-C9 heteroaryl, C3-C9 heteroalicyclyl, C6-C12 aralkyl, C6-C12 heteroaralkyl, C6-C12 (heteroalicyclyl)alkyl, C2-C6 alkoxy, C5-C9 aryloxy, C2-C6 acyl, carboxyl, C1-C6 ester, mercapto, C1-C6 alkylthio, C5-C9 arylthio, cyano, halogen, C1-C6 carbonyl, C1 -C6 ketone, C1-C6 thiocarbonyl, O-carbamyl, N- carbamyl, O-thiocarbamyl, N-thiocarbamyl, C-amido, N-amido, S-sulfonamido, N- sulfonamido, C-carboxy, O-carboxy, isocyanato, thiocyanato, isothiocyanato, nitro, silyl, C1-C6 sulfenyl, sulfinyl, sulfonyl, C1-C6 haloalkyl, C1-C6 haloalkoxy, trihalomethanesulfonyl, trihalomethanesulfonamido or combinations thereof, and R5 and R6 when present may be connected by an C1-C6 alkyl, C1-C6 alkoxy, C2-C6 alkenyl, C2-C6 alkynyl, C5-C9 heteroaryl, or C1-C6 heteroalkyl linkage;A is selected from C, N, S or 0, provided that when A is 0 or S, R5 or R6 will not be present; when A is N, only R5 or R6 will be present; and when A is C, both R5 and R6 will be present.

[0020] Within these generic and subgeneric structures of the free radical stabilizer used herein, illustrative and desirable examples include Sesamol [or, 3,4- (methylenedioxy)phenol], 4-(3,4-methylenedioxy)phenyl-2-butanone, and 3,4’-(methylenedioxy)acetophenone. Combinations of these examples may also be used. Among these examples Sesamol is desirable.

[0021] The free radical inhibitor should be present in an amount of about 10 ppm up to and including about 10,000 ppm, such as about 25 ppm up to and including about 5,000 ppm, desirably about 50 ppm up to and including about 1 ,000 ppm, and more desirably about 100 ppm up to and including about 500 ppm.

[0022] In addition, with these generic and subgeneric structures, and these species within the generic and subgeneric structures, quinones, such as hydroquinone, may be used, though at levels lower than that ordinarily used. For instance, in such instances a quinone in an amount less than about 100 ppm may be used.

[0023] Accelerators may also be included in the inventive cyanoacrylate compositions, such as any one or more selected from calixarenes and oxacalixarenes, silacrowns, crown ethers, cyclodextrins, poly(ethyleneglycol) di(meth)acrylates, ethoxylated hydric compounds and combinations thereof.

[0024] Of the calixarenes and oxacalixarenes, many are known, and are reported in the patent literature. See e.g. U.S. Patent Nos. 4,556,700, 4,622,414, 4,636,539, 4,695,615, 4,718,966, and 4,855,461 , the disclosures of each of which are hereby expressly incorporated herein by reference.

[0025] For instance, as regards calixarenes, those within the following structure are useful herein:where in this regard R1is alkyl, alkoxy, substituted alkyl or substituted alkoxy; R2is H or alkyl; and n is 4, 6 or 8. The alkyl, alkoxy, substituted alkyl or substituted alkoxy desirably are C1-C5 groups.

[0026] One particularly desirable calixarene is tetrabutyl tetra[2-ethoxy-2- oxoethoxy]calix-4-arene.

[0027] A host of crown ethers are known. For instance, any one or more of 15- crown-5, 18-crown-6, dibenzo-18-crown-6, benzo-15-crown-5-dibenzo-24-crown-8, dibenzo-30-crown-10, tribenzo-18-crown-6, asym-dibenzo-22-crown-6, dibenzo-14- crown-4, dicyclohexyl-18-crown-6, dicyclohexyl-24-crown-8, cyclohexyl-12-crown-4, 1 ,2- decalyl-15-crown-5, 1 ,2-naphtho-15-crown-5, 3,4,5-naphtyl-16-crown-5, 1 ,2-methyl- benzo-18-crown-6, 1 ,2-methylbenzo-5, 6-methylbenzo-18-crown-6, 1 ,2-t-butyl-18- crown-6, 1 ,2-vinylbenzo-15-crown-5, 1 ,2-vinylbenzo-18-crown-6, 1 ,2-t-butyl-cyclohexyl- 18-crown-6, asym-dibenzo-22-crown-6 and 1 ,2-benzo-1 ,4-benzo-5-oxygen-20-crown-7 may be used. See U.S. Patent No. 4,837,260 (Sato), the disclosure of which is hereby expressly incorporated herein by reference. Of the silacrowns, again many are known, and are reported in the literature.

[0028] Specific examples of silacrown compounds useful in the inventive compositions include:di methy Isi la-11 -crown-4;d i methy I si I a- 14-crown-5;and dimethylsila-17-crown-6.See e.g. U.S. Patent No. 4,906,317 (Liu), the disclosure of which is hereby expressly incorporated herein by reference.

[0029] Many cyclodextrins may be used in connection with the present invention. For instance, those described and claimed in U.S. Patent No. 5,312,864 (Wenz), the disclosure of which is hereby expressly incorporated herein by reference, as hydroxyl group derivatives of an a, or y-cyclodextrin which is at least partly soluble in the cyanoacrylate would be appropriate choices for use herein as the first accelerator component.

[0030] For instance, polyethylene glycol) di(meth)acrylates suitable for use herein include those within the following structure:where n here is greater than 3, such as within the range of 3 to 12, with n being 9 as particularly desirable. More specific examples include PEG 200 DMA, (where n is about 4) PEG 400 DMA (where n is about 9), PEG 600 DMA (where n is about 14), and PEG 800 DMA (where n is about 19), where the number (e.g., 400) represents the average molecular weight of the glycol portion of the molecule, excluding the two methacrylate groups, expressed as grams / mole (i.e. , 400 g / mol). A particularly desirable PEG DMA is PEG 400 DMA.

[0031] And of the ethoxylated hydric compounds (or ethoxylated fatty alcohols that may be employed), appropriate ones may be chosen from those within the following structure:where Cmcan be a linear or branched alkyl or alkenyl chain, m is an integer between 1 to 30, such as from 5 to 20, n is an integer between 2 to 30, such as from 5 to 15, and R here may be H or alkyl, such as C1-6 alkyl.

[0032] When used, the accelerator embraced by the above structures should be included in the compositions in an amount within the range of from about 0.01 % to about 10% by weight, with the range of about 0.1 to about 0.5% by weight being desirable, and about 0.4% by weight of the total composition being particularly desirable.

[0033] Other additives may be included in the inventive cyanoacrylate compositions, such as certain acidic materials (like citric acid), thixotropy or gelling agents, thickeners (like polymethylmethacrylate), dyes, and combinations thereof.

[0034] In another aspect of the invention, there is provided a method of bonding together two substrates, which method includes applying to at least one of the substrates a composition as described above, and thereafter mating together the substrates for a time sufficient to permit the adhesive to fixture.

[0035] In yet another aspect of the invention, there is provided reaction products of the so-described compositions.

[0036] In still another aspect of the invention, there is provided a method of preparing the so-described compositions. The method includes providing a cyanoacrylate component, and combining therewith with mixing a benzodioxol- containing free radical stabilizer.

[0037] The invention will be further illustrated by the examples which follow.EXAMPLES

[0038] Unless otherwise specified, all samples were prepared using ethyl cyanoacrylate (“ECA”) either without any stabilizer or with the stabilizer and amount noted.

[0039] The unstabilized and the HQ-stabilized ECA samples (shown first below in Table 1) are used for comparative purposes at various levels to measure shelf-life stability through the increase of viscosity over time at the noted elevated temperature conditions.

[0040] Viscosity measurements of all samples were carried out on a Physica viscometer, cone and plate with CP75 at 3000s_1at a temperature of 25°C.Table 1 :Viscosity (mPa.s) of Ethyl Cyanoacrylate Monomer with Various Levels of HQ (Control)

[0041] In Table 2 below, HQ-stabilized ECA samples at the various levels noted above in Table 1 are used to calculate the viscosity ratio of each sample, which is the measured value at the time noted under those elevated temperature conditions divided by the initial viscosity.Table 2:Viscosity Ratio of Ethyl Cyanoacrylate Monomer with Various Levels of HQ (Control)

[0042] HQ is a commonly used free-radical stabilizer in cyanoacrylates, ordinarily at a level of 500 ppm to 1000 ppm. Excellent stability of the monomer is observed with viscosity ratios of 1 .40 - 1 .90 recorded after 10 days aging at 82°C.

[0043] In Table 3 below, unstabilized and Sesamol-stablized ECA samples at various levels are used to measure shelf-life stability through the increase of viscosity over time at the noted elevated temperature conditions.Table 3:Viscosity (mPa.s) of Ethyl Cyanoacrylate Monomer with Various Levels of Sesamol

[0044] In Table 4 below, Sesamol-stablized ECA samples at the various levels noted above in Table 3 are used to calculate the viscosity ratio of each sample, which is the measured value at the time noted under those elevated temperature conditions divided by the initial viscosity.Table 4:Viscosity Ratio of Ethyl Cyanoacrylate Monomer with Various Levels of Sesamol

[0045] Sesamol is shown to be a very effective stabilizer of ECA monomer. At levels of 500ppm and WOOppm, it achieved viscosity ratios similar to the corresponding HQ stabilized ECA samples. At a level of 100ppm, HQ was ineffective at stabilizing the ECA monomer (gelled after 10 days aging at 82°C) while unexpectedly at this low level (100 ppm), Sesamol was effective at stabilizing the monomer under the same conditions achieving a viscosity ratio of 5.19.

[0046] In Table 5 below, unstabilized and 4-(3,4-methylenedioxy) phenyl-2- butanone-stablized ECA samples at 1000 ppm and 5000 ppm are used to measure shelf-life stability through the increase of viscosity over time at the noted elevated temperature conditions.Table 5:Viscosity (mPa.s) of Ethyl Cyanoacrylate Monomer with Various Levels of Sesamol Derivatives

[0047] In Table 6 below, 4-(3,4-methylenedioxy)phenyl-2-butanone-stablized ECA samples at the various levels noted above in Table 5 are used to calculate the viscosityratio of each sample, which is the measured value at the time noted under those elevated temperature conditions divided by the initial viscosity.Table 6:Viscosity Ratio of Ethyl Cyanoacrylate Monomer with Various Levels of Sesamol Derivatives

[0048] Other structurally-related derivatives of Sesamol such as 4-(3,4- methylenedioxy)phenyl-2-butanone and 3,4’-methylendioxy)acetophenone were demonstrated to be capable of stabilizing the ECA monomer.

[0049] In Table 7 below, HQ-stabilized and Sesamol-stablized beta-methoxy cyanoacrylate (“BMeOCA”) samples at the noted levels are used to measure shelf-life stability through the increase of viscosity over time at the noted elevated temperature conditions.Table 7:Viscosity (mPa.s) of Betamethoxyethyl Cyanoacrylate Monomer with Various Levels of Sesamol

[0050] In Table 8 below, Sesamol-stabilized and HQ-stabilized BMeOCA samples at the various levels noted above in Table 7 are used to calculate the viscosity ratio ofeach sample, which is the measured value at the time noted under those elevated temperature conditions divided by the initial viscosity.Table 8:Viscosity Ratio of Betamethoxyethyl Cyanoacrylate Monomer with Various Levels of Sesamol

[0051] Not only is Sesamol an effective stabilizer of ECA monomer, it has also been demonstrated to provide stability to other cyanoacrylate monomers, BMeOCA.BMeOCA remained liquid with viscosity ratios of 3.33 - 13.00 being observed and recorded following 10 days aging at 82°C at levels of 100 ppm to 1000 ppm.

Claims

What we Claim is:1 . A cyanoacrylate composition, comprising:(a) a cyanoacrylate component;(b) a free radical inhibitor comprising a benzodioxol.

2. The composition of Claim 1 , wherein the free radical inhibitor is represented by the following structure:wherein R1 , R2, R3, R4 , R5, and R6 are independently selected from H, OH, linear or branched C1-C6 alkyl, linear or branched C1-C6 alkoxy, linear or branched C2-C6 alkenyl, linear or branched C2-C6 alkynyl, C5-C9 aryl, C3-C9 cycloalkyl, C4-C9 cycloalkenyl, C4-C9 cycloalkynyl, C5-C9 heteroaryl, C3-C9 heteroalicyclyl, C6-C12 aralkyl, C6-C12 heteroaralkyl, C6-C12 (heteroalicyclyl)alkyl, C2-C6 alkoxy, C5-C9 aryloxy, C2-C6 acyl, carboxyl, ester, mercapto, alkylthio, arylthio, cyano, halogen, carbonyl, ketone, thiocarbonyl, O-carbamyl, N-carbamyl, O-thiocarbamyl, N- thiocarbamyl, C-amido, N-amido, S-sulfonamido, N-sulfonamido, C-carboxy, O-carboxy, isocyanato, thiocyanato, isothiocyanato, nitro, silyl, sulfenyl, sulfinyl, sulfonyl, haloalkyl, haloalkoxy, trihalomethanesulfonyl, trihalomethanesulfonamido or combinations thereof, and R5 and R6 when present may be connected by an alkyl, alkoxy, alkenyl, alkynyl, heteroaryl, or heteroalkyl linkage;A is selected from C, N, S or 0, provided that when A is 0 or S, R5 or R6 will not be present; when A is N, only R5 or R6 will be present; and when A is C, both R5 and R6 will be present.

3. The composition of any preceding claim, wherein the free radical inhibitor is represented by the following structure:wherein R1 , R2, R3, R4 , R5, and R6 are independently selected from H, OH, linear or branched C1 -C6 alkyl, linear or branched C1 -C6 alkoxy, linear or branched C2-C6 alkenyl, linear or branched C2-C6 alkynyl, C5-C9 aryl, C3-C9 cycloalkyl, C4-C9 cycloalkenyl, C4-C9 cycloalkynyl, C5-C9 heteroaryl, C3-C9 heteroalicyclyl, C6-C12 aralkyl, C6-C12 heteroaralkyl, C6-C12 (heteroalicyclyl)alkyl, C2-C6 alkoxy, C5-C9 aryloxy, C2-C6 acyl, carboxyl, ester, mercapto, alkylthio, arylthio, cyano, halogen, carbonyl, ketone, thiocarbonyl, O-carbamyl, N-carbamyl, O-thiocarbamyl, N- thiocarbamyl, C-amido, N-amido, S-sulfonamido, N-sulfonamido, C-carboxy, O-carboxy, isocyanato, thiocyanato, isothiocyanato, nitro, silyl, sulfenyl, sulfinyl, sulfonyl, haloalkyl, haloalkoxy, trihalomethanesulfonyl, trihalomethanesulfonamido or combinations thereof.

4. The composition of any preceding claim, wherein the free radical inhibitor is represented by the following structure:wherein R1 , R2, R3, R4 , R5, and R6 are independently selected from H, OH, linear or branched C1 -C6 alkyl, linear or branched C1 -C6 alkoxy, linear or branched C2-C6alkenyl, linear or branched C2-C6 alkynyl, C5-C9 aryl, C3-C9 cycloalkyl, C4-C9 cycloalkenyl, C4-C9 cycloalkynyl, C5-C9 heteroaryl, C3-C9 heteroalicyclyl, C6-C12 aralkyl, C6-C12 heteroaralkyl, C6-C12 (heteroalicyclyl)alkyl, C2-C6 alkoxy, C5-C9 aryloxy, C2-C6 acyl, carboxyl, ester, mercapto, alkylthio, arylthio, cyano, halogen, carbonyl, ketone, thiocarbonyl, O-carbamyl, N-carbamyl, O-thiocarbamyl, N- thiocarbamyl, C-amido, N-amido, S-sulfonamido, N-sulfonamido, C-carboxy, O-carboxy, isocyanato, thiocyanato, isothiocyanato, nitro, silyl, sulfenyl, sulfinyl, sulfonyl, haloalkyl, haloalkoxy, trihalomethanesulfonyl, trihalomethanesulfonamido or combinations thereof, and R5 and R6 when present may be connected by an alkyl, alkoxy, alkenyl, alkynyl, heteroaryl, or heteroalkyl linkage;A is selected from C, N, S or 0, provided that when A is 0 or S, R5 or R6 will not be present; when A is N, only R5 or R6 will be present; and when A is C, both R5 and R6 will be present.

5. The composition of any preceding claim, wherein the free radical inhibitor is a member selected from the group consisting of Sesamol, 4-(3,4-methylenedioxy)phenyl- 2-butanone, 3,4’-(methylenedioxy)acetophenone, and combinations thereof.

6. The composition of any preceding claim, wherein the free radical inhibitor further comprises a quinone.

7. The composition of any preceding claim, wherein the free radical inhibitor further comprises a hydroquinone.

8. The composition of any preceding claim, wherein the free radical inhibitor further comprises a quinone in an amount less than about 100 ppm.

9. The composition of any preceding claim, wherein the free radical inhibitor is present in an amount of about 10 ppm up to and including about 10,000 ppm.

10. The composition of any preceding claim, wherein the free radical inhibitor is present in an amount of about 25 ppm up to and including about 5,000 ppm.11 . The composition of any preceding claim, wherein the free radical inhibitor is present in an amount of about 50 ppm up to and including about 1,000 ppm.

12. The composition of any preceding claim, wherein the free radical inhibitor is present in an amount of about 100 ppm up to and including about 500 ppm.

13. The composition of any preceding claim, wherein the cyanoacrylate component is represented by H2C=C(CN)-COOR, wherein R is selected from C1-15 alkyl, alkoxyalkyl, cycloalkyl, alkenyl, aralkyl, aryl, allyl and haloalkyl groups.

14. The composition of any preceding claim, wherein the cyanoacrylate component is present in an amount of about 90 percent by weight to about 99 percent by weight, based on the total weight of the composition.

15. The composition of any preceding claim, wherein the cyanoacrylate component is present in an amount of about 65 percent by weight to about 90 percent by weight, based on the total weight of the composition.

16. The composition of any preceding claim, wherein the cyanoacrylate component comprises ethyl-2-cyanoacrylate.

17. The composition of any preceding claim, wherein the cyanoacrylate component comprises beta methoxy-2-cyanoacrylate.

18. The composition of any preceding claim, further comprising an accelerator component selected from the group consisting of calixarene, oxacalixarene, silacrown, cyclodextrin, crown ether, poly(ethyleneglycol) di(meth)acrylate, ethoxylated hydric compound, and combinations thereof.

19. The composition of Claim 18, wherein the calixarene is tetrabutyl tetra[2-ethoxy- 2-oxoethoxy]calix-4-arene.

20. The composition of Claim 18, wherein the crown ether is selected from members within the group consisting of 15-crown-5, 18-crown-6, dibenzo-18-crown-6, benzo-15- crown-5-dibenzo-24-crown-8, dibenzo-30-crown-10, tribenzo-18-crown-6, asym- dibenzo-22-crown-6, dibenzo-14-crown-4, dicyclohexyl-18-crown-6, dicyclohexyl-24- crown-8, cyclohexyl-12-crown-4, 1 ,2-decalyl-15-crown-5, 1 ,2-naphtho-15-crown-5, 3,4,5-naphtyl-16-crown-5, 1 ,2-methyl-benzo-18-crown-6, 1 ,2-methylbenzo-5, 6- methylbenzo-18-crown-6, 1 ,2-t-butyl-18-crown-6, 1 ,2-vinylbenzo-15-crown-5, 1 ,2- vinylbenzo-18-crown-6, 1 ,2-t-butyl-cyclohexyl-18-crown-6, asym-dibenzo-22-crown-6, and 1 ,2-benzo-1 ,4-benzo-5-oxygen-20-crown-7 and combinations thereof.

21. The composition of Claim 18, wherein the poly(ethyleneglycol) di(meth)acrylate is within the following structure:wherein n is greater than 3.

22. The composition of any preceding claim, further comprising a thixotropy conferring agent or a thickener.

23. The composition of any preceding claim, further comprising a rubber toughening component.

24. A method of bonding together two substrates, comprising the steps of: applying a cyanoacrylate composition of any preceding claim, to at least a portion of at least one of the substrates andmating together the substrates for a time sufficient to permit the composition to fixture.

25. A method of preparing a cyanoacrylate composition of any of Claims 1 to 23, comprising the steps of: providing a cyanoacrylate component, and combining therewith with mixing a free radical inhibitor comprising a benzodioxol.

26. Use of a benzodioxol as a free radical inhibitor in a curable adhesive composition, for example a curable cyanoacrylate composition.

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