Filled Cyanoacrylate Adhesive Compositons

 United’ States:Patent [19, Sato et al. 4,837,260 Jun. 6, 1989 [11] Patent Number: [45] Date of Patent: [54] CY ANOACRYLATE COMPOSITIONS Mitsuyoshi Sato; Takumi Okamura; Kaoru Kimura, all of Nagoya, Japan Toagosei Chemical Industry Co., Ltd., Tokyo, Japan [21] App1.No.: 48,894 [75] Inventors: [73] Assignee: [22] Filed: May 12, 1987 [30] Foreign Application Priority Data May 23, 1986 [JP] Japan .................. .. . 61-117189 Mar. 25, 1937 [JP] Japan ................................ .. 62-69084 [51] Int. cu .............................................. .. C08K 5/24 [52] U.S. Cl. .................................. .. 524/261; 523/212; 524/377 [58] Field of Search ............... .. 523/212; 524/261, 377 [56] References Cited U.S. PATENT DOCUMENTS 2,436,144 2/1948 I-lowk et al. ............. .., ........ .. 260/37 2,765,332 10/1956 Coover Jr. et al. . 525/295 3,178,379 4/1965 Wicker et al. 525/295 3,220,960 11/1965 Wichterle . . . . . . . . .. 260/2.5 3,361,858 1/1968 Wichterle 264/1 3,388,199 6/1968 Chaney et al. 264/182 3,427,298 2/1969 Tsuboi et al. ..... .. 260/91.3 3,658,749 4/1972 Gordon ...... .. 260/37 PC 3,663,501 5/1972 Adams et a1. ...... .. 523/212 3,839,065 10/1974 Overhults et a1. 523/212 3,940,362 2/1976 Overhults ...... .. 523/212 4,105,715 8/1978 Gleave ....... .. 156/331 X 4,139,693 2/1979 Schoenberg 526/297 4,170,585 10/1979 Motegi et al. 526/245 4,171,416 10/1979 Motegi et al. 526/245 4,180,913 1/1980 Takeuchi et al. ................. .. 438/404 4,313,865 2/1982 Teranota et al. . . . . . . . . . . .. 526/278 4,444,933 4/1984 Columbus .... .. .. 524/297 4,477,607 10/1984 Litke . . . . . . . . . . . . . . .. 523/212 4,533,422 8/1985 Litke ........ .. .. 523/212 4,550,041 10/1985 Thompson 428/35 4,713,405 12/1987 Koga et al. ...... .. .. 523/212 4,720,513 1/1988 Kameyatna et al. .............. .. 523/212 FOREIGN PATENT DOCUMENTS 53-91995 8/1978 Japan. 53-103092 9/1978 Japan. 0043247 4/1979 Japan . 0034165 9/1980 Japan. OTHER PUBLICATIONS Harris, et al., J. Polymer Sci. A-1, 4, 665-677 (1966). Haas, et al., J. Polymer Sci., 22, 291 (1956). ' L. A. vol.’f, et al., Khim Volokna, 2, 14 (1979). J. Chernikov, et al., Nauchn Tr., Kuban Gos. Univ., 243, 141 (1977). Primary Examiner—Joseph L. Schofer Assistant Examiner—-J. M. Reddick Attorney, Agent, or Firm—-Wyatt, Gerber, Burke and Badie [57] ABSTRACT A cyanoacrylate composition suitable as cyanoacrylate adhesives for bonding porous materials, shaping mate- rial and fingerprint detectors comprises a 2-cyanoacry- late as a main component and at least one of crown ethers, polyalkylene oxides and derivatives of the poly- alkylene oxides as a curing accelerator and at least one of hydrophobic silicas. 16 Claims, No Drawings 4,837,260 1 CY ANOACRYLATE COMPOSITIONS . BACKGROUND OF THE INVENTION This invention relates to a cyanoacrylate composition mainly composed of 2-cyanoacrylate. According to this invention, there are provided compositions which can be used as adhesives having rapid setting time, excellent workability and good storage stability for adhesion of various hard-to-bond porous material such as woods, papers, leather, etc., compositions for molding materials reinforcedby mixing with glass fibers, polyethylene fibers, etc. and furthermore, compositions useful for detection of fingerprints. Adhesives comprising cyanoacrylate compositions have been widely used as instantaneous adhesives in industrial fields, medical fields, leisure fields and in general household use because of their property that they readily undergo anionic polymerization due to adsorbed water on the surface of the materials to be bonded, are rapidly cured and their characteristics that they have low viscosity and are free-flowing one-pack type solventless adhesives. The compositions of this invention can be similarly used as adhesives in these fields. The fields for applica- tion thereof are further extended because of rapid cur- ability, workability and stability in bonding of porous materials. In addition, the compositions of this invention may also be used for shaping materials and for detection of fingerprints. _ . The following two methods have been mainly em- ployed to prevent absorption of adhesives into porous . materials when porous materials such as woods, papers, leathers, etc. which are difficult to bond are to be bonded with cyanoacrylate adhesives or to prevent sagging of the adhesives when microgaps are bonded by penetration bonding. According to one of them, one surface of material to be bonded is pretreated with a primer containing amines which are curing agents and then treated with a cyano- acrylate adhesive, or curing accelerators are previously mixed in the cyanoacrylate adhesive. As the curing accelerators, there are known complexes of imidazoles - and S02 (U.S.Pat. No. 3993678), caffeine, theobromine (U.S. Pat. No. 4042442), polyalkylene oxide and its esters or ethers (Japanese Patent Examined Publication No.37836/ 85) corresponding to U.S. Pat. No. 4,170,585, crown ethers (Japanese Patent Examined Publication No.2238/ 80) corresponding to U.S. Pat. No. 4,171,416, podant compounds (U.S. Pat. No. 4386193), normal or acid salts of amines or imines (Japanese Patent Unexam- ined Publication No.l4l827/79), alcohols, alcohol ester derivative compounds (Japanese Patent Unexamined Publication No.l2166/80), polyethylene glycol dime- thacrylic esters (Japanese Patent Unexamined Publica- tion No.200469/ 82), S03 complexes of tertiary amines, sulfonium tetrafluoroborate (Japanese Patent Unexam- ined Publication No.87170/ 83), polyethylene/propy- lene oxide monoacrylate, etc. (Japanese Patent'Exam- ined Publication No.26513/85), compounds obtained by the reaction of siloxane, phosphoric acid, dicarboxylic acids or their acid chloride, acid anhydride, etc. with diols (Japanese Patent Unexamined Publication No.90277/ 85), calixarene (Japanese Patent Unexamined Publication No.l79482/85), etc. According to another method, the adhesives are made highly viscous using thickening agents such as polymethyl methacrylate, acrylic rubbers and the like 5 10 15 20 25 30 35 40 45 50 55 60 65 2 to inhibit absorption of the adhesives into the porous materials. Adhesives of high viscosity which have thixotropic properties are preferred and so, thickening agents which impart thixotropic properties have also been studied and use of fumed silica has been proposed (U.S. Pat. No. 4477607). When porous materials such as woods, papers, leath- ers, etc. are bonded by the above two methods, there are the‘ following problems, which hinder further exten- sion of scope of application of cyanoacrylate adhesives. When curing agents are used and when they are used as primers, an operation of pretreatment of the surface to be bonded is required and this negates the important characteristic of one-pack curing of cyanoacrylate ad- hesives. Thus, extension of uses cannot be expected, although the instantaneous bonding ability is main- tained. Further, inhibition of absorption of adhesives only with addition of curing agent requires a large amount of curing agent, which damages storage stabil- ity of adhesives. On the other hand, when a thickening agent is used in order to inhibit the absorption of adhe- sives into the porous materials, in many cases, it is used in combination with said curing agent to adjust setting time of the adhesives. In this case, when it is attempted to obtain sufficient viscosity, there often occurs string- ing, which considerably damages the workability. Fumed silica has been proposed as a thickening agent which causes less stringing and provides thixotropic properties, but use of fumed silica has the problems of separation of components contained in adhesives and settling of fillers. Further, it is difficult to substantially inhibit the absorption of adhesives into porous materials only by increasing the viscosity using a thickening agent. Besides, there occur other problems such as re- duction of coatability and bond performance when viscosity is increased. Setting time can be adjusted by joint use of curing accelerators and by increase or de- crease of the amount added, but as explained before, with increase of the amount added, storage stability is appreciably reduced. SUMMARY OF THE INVENTION The object of this invention is to provide composi- tions which are useful as cyanoacrylate adhesives, which are free from the above mentioned problems and which have high thixotropic properties, have superior rapid curability and excellent workability in bonding of porous materials and are excellent in storage stability and also useful for other purposes. DESCRIPTION OF THE INVENTION As a result of the inventors’ intensive researches in an attempt to solve the above mentioned problems, it has been found that use of 2-cyanoacrylate in combination with a specific curing accelerator and a hydrophobic silica overcomes all of the problems. That is, this invention relates to a cyanoacrylate com- position, characterized by containing at least one com- pound indicated by the following A and at least one compound indicated by the following B. A: crown ether, polyalkylene oxide and its deriva- tives. B: a hydrophobic silica 2-Cyanoacrylates: 2-Cyanoacrylates (2-cyanoacrylic acid esters) are those used as a main component of cyanoacrylate adhesives which have been widely used as instanta- 4,837,260 3. neous adhesives. Cyanoacrylate adhesives usually contain additives such as anionic polymerization inhibitors, radical polymerization inhibitors, thick- ening agents, plasticizers, dyes, pigments and per- fumes in addition _to 2-cyanoacrylates as a main component. These additives may also be used in the composition of this invention. As examples of 2-cyanoacrylates, mention may be made of methyl, ethyl, chloroethyl, n-propyl, i-propyl, allyl, propargyl, n-butyl, i-butyl, t-butyl, n-pentyl, n- hexyl, cyclohexyl, phenyl, tetrahydrofurfuryl, heptyl, 2-ethylhexyl, n-octyl, nonyl, oxononyl, decyl, n-dode- cyl, ethoxyethyl, 3-methoxybutyl, ethoxyethoxyethyl, tritluoroethyl and hexafluoroisopropyl esters of 2- cyanoacrylic acid. ' The anionic polymerization inhibitor which is an additive when the composition of this invention is used as cyanoacrylate adhesives is for inhibition of anionic polymerization of the composition caused by water and the like. Examples thereof are S02, S03, NO, N02, HCl, H3PO4, acid phosphates, aromatic sulfonic acid, alkylsulfonic acids, propanesultone, trifluoromethane- sulfonic acid, perfluoroalkylcarboxylic acids, etc. This anionic polymerization inhibitor is added in an amount of 1-1000 ppm, preferably 5-100 ppm. The radical polymerization inhibitor is added mainly for inhibiting radical polymerization and anaerobic pol- ymerization which take place with light, etc. during storage. Examples thereof are phenol, cresol, hydroqui- none, hydroquinone monomethyl ether, catechol, pyro- gallol, etc. Generally, this is added in angamount of 10—10,000 ppm, preferably 100-5000 ppm. The thickening agent is added for adjusting the vis- cosity of the adhesive composition and it further has an effect of improving dispersion stability. Examples thereof are polymethyl methacrylate, polymethyl acry- late, po1yalkyl-2-cyanoacrylate, acrylic rubber, polyvi- nyl acetate, polyvinyl ether, cellulose ester, etc. This is added usually in an amount of 1—l0% depending on the desired viscosity. Crown ethers: The term “Crown ethers” is often used in a broad sense of macroheterocyclic compounds, but in this in- , vention it means macrocyclic polyethers wherein the only hetero-atoms are oxygen. As examples of these ethers, mention may be made of 15-crown-5, 18-crown- 6, dibenzo-18-crown-6, benzo-1'5-crown-5, dibenzo-24- crown-8, dibenzo-30-crown-10, tribenzo-18-crown-6, asym-dibenzo-22-crown-6, dibenzo-14-crown-4, dicy- clohexyl-18-crown-6, dicyclohexyl-24-crown-8, cy- clohexyl-12-crown-4, 1,2-decalyl-15-crown-5, l,2-naph- tho-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-tert-butyl-l8-crown-6, l,2-vinylbenzo- 15-crown-5, 1,2-vinylbenzo-18-crown-6, 1,2-tert-butyl- cyclohexyl-18-crown-6, asym-dibenzo-22-crown-6, l,2- benzo-1,4-benzo-5-oxygen-20-crown-7, etc. Polyalkylene oxides: “Polyalkylene oxides” means polymers which con- tain, as a main component, one or two or more of com- pounds such as alkylene oxides, e.g., ethylene oxide, propylene oxide, butylene oxide, trimethylene oxide, tetramethylene oxide (tetrahydrofuran), 1,3-dioxolan, trioxane, tetraoxane, etc. and those of which hydrogen in alkylene group is substituted with a halogen-atom, hydroxyl group, phenyl group, etc., such as epichloro- hydrin, epibromohydrin, glycidol, styrene oxide, etc. 10 I5 20 25 30 35 40 45 50 55 60 65 4 and further include polymers mainly composed of form- aldehyde, acetaldehyde, glycerin, etc. These polymers are required to have a polymeriza- tion degree of at least 2, preferably about 4-3000, but naturally, those of 1000 or higher in polymerization degree may also be used, in some cases. Molecular weight of the polymers which is connected with poly- merization degree is preferably 400—1,000,000, more preferably l000—10,000. When polymerization degree is 1 or less (i.e., less molecular weight), the effect of set- ting time accelerator is small and it is difficult to obtain compositions having thickening effect and thixotropic properties which are desirable in accordance with this invention. When polymerization degree" is far more than 10000, namely, molecular weight is larger, compatibil- ity of the polymers with 2-cyanoacrylate tends to de- crease and it becomes difficult to produce a homogene- ous composition. It is not clear why setting time is ac- celerated when polymerization degree is 2 or more, but this is considered because oxygen atoms in the chain polyalkylene oxide coordinate with a metal. Compounds in which the alkylene group has 2-6 carbon atoms, are superior in acceleration of setting time and are preferred for this invention, among which those having ethylene, propylene, isopropylene or tetra- methylene groups or combinations thereof are pre- ferred. Especially preferred as those having propylene or tetramethylene or combination thereof. As examples of polyalkylene oxides used in this in- vention, the following may be mentioned. Diethylene glycol, triethylene glycol, tetraethylene glycol, poly- ethylene glycol, polypropylene glycol, poly 1,3-propy- lene glycol, polytrimethylene oxide, polytetramethyl- ene oxide, polyepichlorohydrin, poly 3,3-bis(- chloromethyl) butylene oxide, polytetramethylene ether glycol, poly 1,3-dioxolan, poly 2,2-bis(- chloromethyl) propylene oxide, ethyleneoxide-propy- lene oxide block polymer, polyglycerins such as diglyc- erin, triglycerin, tetraglycerin, etc., formaldehyde con- densates, acetaldehyde condensates, trioxane polymers, etc. Furthermore, various polyalkylene oxides sold as polyols for curing polyether type urethanes may also be used in this invention. Polyalkylene oxide derivatives: The polyalkylene oxide derivatives used in this inven- tion include typically esters of the above polyalkylene oxides with acids and ethers with hydroxyl group-con- taining compounds. These are preferred, but this inven- tion is not limited to use of them and those which have a polyalkylene oxide structure in molecule thereof in- cluding those which have various substituents at termi- nals of molecule and those which have other bonding links in polyalkylene oxide can exhibit the effects of this invention. As examples of acids which may constitute the esters, mention may be made of acetic acid, propi- onic acid, butyric acid, iso-butyric acid, pivalic acid, pentanoic acid, n-hexanoic acid, 2-methylpentanoic acid, t-butylacetic acid, n-heptanoic acid, n-octanoic acid, n-decanoic acid, lauric acid, palmitic acid, stearic acid, oleic acid, cyclohexylcarboxylic acid, cyclopen- tylcarboxylic acid, cyclopropylcarboxylic acid, acrylic acid, methacrylic acid, maleic acid, itaconic acid, napth- thenic acid, benzoic acid, Bmaphthylcarboxylic acid, p-toluenecarboxylic acid, furancarboxylic acid, p- chlorobenzoic acid, monochloroacetic acid, cyanoace- tic acid, glycolic acid, lactic acid, phenyloxypropionic acid, succinic acid, glutaric acid, adipic acid, sebacic acid, butanetetracarboxylic acid, aconitic acid, pro- 4,837,260 5 pane-1,2,3-tricarboxylic acid, citric acid, ortho-phthalic acid, iso-phthalic acid, trimellitic acid, etc. As examples of the hydroxyl group-containing compounds which may constitute the ethers, mention may be made of methanol, ethanol, propanol, isopropanol, butanol, iso- _butanol, hexanol, cyclohexanol, 2-ethyl octanol, deca- nol, lauryl alcohol, cetyl alcohol, stearyl alcohol, oleyl alcohol, phenol, a-naphthol, B-naphthol, cresol, t-butyl phenol, octyl phenol, nonyl phenol, p-chlorophenol, resol, bisphenol A, 2-chloroethanol, ethylene cyanohy- drin, trifluoroethanol, benzyl alcohol, 1,4-butanediol, 1,6-hexanediol, glycerin, sorbitol, hydrogenated bisphe- nol A, trimethylolpropane, etc. As examples of the esters and ethers as the polyalkyl- ene oxide derivatives, mention may be made of diethyl- ene glycol monoalkyl ethers (e.g., methyl, ethyl, pro- pyl, butyl, etc. as the alkyl), diethylene glycol dialkyl ethers (e.g., methyl, ethyl, ‘ propyl, butyl, etc. as the alkyl), polyethylene glycol monoalkyl ethers (e.g.,‘ methyl, ethyl, propyl, lauryl, cetyl, stearyl, oleyl, etc. as the alkyl), polypropylene glycol monoalkyl ethers (e.g., methyl, ethyl, lauryl, propyl, stearyl, cetyl, oleyl, per- tluoroalkyl, etc. as the alkyl), polyethylene glycol monoaryl ethers (e.g., octylphenyl, nonylphenyl, etc. as the aryl), polyethylene glycol dialkyl ethers, polyethyl- ene glycol monoalkyl esters (e.g., acetates trifluoroace- tates, laurates, stearates, oleates, methacrylates, etc.), polyethylene glycol diesters, polypropylene glycol di- esters, bisphenol A-polyalkylene oxide adducts (e.g., ethylene, propylene, etc as the alkylene, the same being applied to the following adducts), hydrogenated bisphe- nol A-polyalkylene oxide adducts, trimethylolpropane- polyalkylene oxide adducts, glycerine-polyalkylene oxide adducts, polyoxyethylene sorbitan ester, tet- raoleic acid-polyoxyethylenesorbitol, adipic acid- polyalkylene oxide adducts, trimellitic acid-polyalky- lene oxide adducts, isocyanate compounds-polyalky- lene oxide adducts, phosphoric acid-polyalkylene oxide adducts, silica acid-polyalkylene oxide adducts, (poly- oxyalkylene) polysilanolates, (polyoxyalkylene) polyes- ters, (polyoxyalkylene) polyphosphates, etc. Hydrophobic silica: . The hydrophobic silica used in this invention can be obtained by contacting a hydrophilic silica with a com- pound capable of reacting with hydroxyl group present on the surface of hydrophilic silica in some form to produce hydrophobic group or a compound capable of being adsorbed onto the surface of hydrophilic silica to form a hydrophobic layer on said surface (these com- pounds being called “surface treating agent” hereinaf- ter) in the presence or absence of a solvent and prefera- bly, heating them to render hydrophobic the surface of hydrophilic slilica. As the hydrophilic silica used for production of the hydrophobic silica, there may be used, for example, fumed silica and wet silica, which has preferably 1-100 pm, more preferably 5-50 pm in particle diameter of primary particles. Such particulate silica includes, for example, highly-dispersible amorphous silica obtained by hydrolysis of silicon tetrachloride in oxygen-hydro- gen flame. Furthermore, there may also be used alumi- na-containing silica, titanium oxide-containing silica and iron oxide-containing silica obtained by effecting said hydrolysis in the presence of chlorides such as titanium chloride, aluminium chloride, iron chloride, etc. As the surface treating agents which convert the surface state of hydrophilic silica to hydrophobic state to produce hydrophobic silica, mention may be made 5 10 15 20 25 30 35 40 45 50 55 65 6 of, for example, hydrophobic group-containing alkyl, aryl and aralkyl silane coupling agents such as n-octyl- trialkoxysilane, etc., silylating agents such as dimethyl- dichlorosilane, hexamethyldisilazane, etc., silicone oils such as polydimethylsiloxane, higher alcohols such as stearyl alcohol, etc., higher fatty acids such as stearic acid, etc. In this invention, it is preferred to use hydrophobic silica obtained by surface-treating hydrophilic silica with so-called dimethylsilylating agent or trimethyl- silylating agent which can provide dimethylsilyl group or trimethylsilyl group on the surface of hydrophilic silica. . As examples of the dimethylsilylating agents and trimethylsilylating agents, in addition to said dimethyl- dichlorosilane and hexamethyldisilazane, mention may be made of dimethyldimethoxysilane, dimethyldiethox- ysilane, dimethyldiacetoxysilane, dimethylditri- fluoroacetoxysilane, hexamethylcyclotrisilazane, trime- thylchlorosilane, trimethylbromosilane, N,O-bis(trime- thy1sily1)carbonate, N,N-diethylaminotrimethylsilane, N,N-dimethylaminotrimethylsilane, hexamethyldisilox- ane, N-trimethylsilylimidazole, bis(trimethylsilyl)aceta- mide, bis(trimethylsilyl)trifluoroacetamide, bis(trime- thylsilyl)urea, 2-trimethylsiloxy-2-pentene-4-one, trime- thylsilylacetamide, trimethylsilyl-N,N’-diphenylurea, 3-trimethylsilyl-2-oxazolidinone, bis(trimethylsiloxy)- dimethylsilane, etc. The hydrophobic silica used in this invention can be obtained by the method mentioned hereabove, but com- mercially available hydrophobic silica may also be used instead. As commercially available hydrophobic silica, there may be used, for example, AEROSIL R805 (Degussa Co.) surface-treated with n-octyltrimethox- ysilane, AEROSIL R202 (Degussa Co.) surface-treated with silicone oil, AEROSIL R972, R974 and R 976 (Degussa Co.) surface-treated with dimethylsilylating agent, AEROSIL R811 and R812 (Degussa Co.) sur- face-treated with trimethylsilylating agent, etc. These are hydrophobic fumed silicas having a specific surface area of 150-:20, 80:20, l10i20, 170:20, 250:25, l50:20 and 200:2O m2/g and a hydrophobic degree of 50, 65, 40, 35, 30, 60 and 60, respectively. As other hydrophobic silica, there is Cab-O-Sil N70-TS (Cabot CO.) which is reported to have a specific surface area of l0O:20 m2/ g and to be treated with an organosilicone compound. Mixing ratio: ~ - Mixing ratio of crown ether, polyalkylene oxide and polyalkylene oxide derivative in cyanoacrylate compo- sition may be optionally set within the range in which storage stability is not damaged and setting time is ac- celerated and depending on the desired viscosity and thixotropic property, but is preferably 0.000l—2O parts by weight, more preferably 0.0005-l0 parts by weight of 100 parts by weight of 2-cyanoacrylate. Although it somewhat varies depending on the kind of the com- pound added, generally, when the amount of the com- pound is smaller, there are provided less acceleration effect of setting time and less viscosity and thixotropic property. When more than 20 parts by weight, there may occur that dissolution becomes difficult, viscosity of composition becomes too high and the rate of gela- tion is greatly increased during storage. Amount of hydrophobic silica to be added may vary depending on particle diameter, hydrophobic degree of silica and kind of the surface treating agent, but is pref- erably such that ratio of viscosities (thixotropic coeffici- 4,837,260 7 ent) measured at rotation speeds of, for example, 6 rpm and 60 rpm in Brookfield viscometer is more than 2, more preferably more than 3 and especially preferably more than 5. Compositions having optional viscosities can be obtained by changing the amount of hydropho- bic silica but preferred amount is l-30% by weight, more preferably 3—20% by weight of the composition. The compositions of this invention, are excellent adhesives having suitable viscosity and thixotropic properties and further possessing excellent adhesiveness and especially high bonding speed and excellent storage stability for firmly bonding porous materials such as woods, leathers and papers which have been difficult to bond with conventional 2-cyanoacrylate adhesives with remarkable workability and at high bonding speed. Further, the composition of this invention can provide adhesives free from the problems of gelation during storage and increase of stringing which have been en- countered in the conventional adhesives of this kind. The mechanism of how suchaction is exhibited is not known. As mentioned above, many curing accelerators and thickening agents for 2-cyanoacrylate adhesives have been known, but the excellent action of this inven- 10 15 20 tion can be exhibited only by combination of specific , ones," namely, combination according to this invention. Especially, it is clear from comparative examples given hereinafter and U.S. Pat. Nos.4477607 and 4533422 that high viscosity cyanoacrylate compositions having thixotropic properties cannot be obtained by single use of hydrophobic silica obtained from hydro- philic silica surface-treated with diemthylsilylating agent or trimethylsilylating agent. Thus, the action exhibited by compositions according to this invention could not have been predicted. COMPARATIVE EXAMPLES 1-3 Three compositions were prepared which contained 15-crown-5, 18-crown-6 or polyethylene glycol #400 of this invention and other additives in the amounts as shown in Table 1. The addition amount in ppm of stabilizer and compo- nent A (crown ether, etc.) in the following tables is based on the amount of 2-cyanoacrylate. Each setting time of these compositions for beeches in an atmosphere of 23° C. and 60%RH was measured according to JIS K6861 and the results are shown in Table 1. As is clear 25 30 35 40 45 8 therefrom, these were 30 seconds for all compositions. Separately, these compositions were placed in sealed vessels of polyethylene and heated at 60° C. for 10 days. Then, each setting time of these compositions for two small pieces of beechwood adhered together and string- ing property thereof were measured. As is clear from Table 1, setting time was 45 seconds, 45 seconds, and 60 seconds, respectively and stringings were 10 cm, 10 cm and 20 cm, respectively. COMPARATIVE EXAMPLE 4-7 Four compositions were prepared which contained AEROSIL R972, AEROSIL R805 or AEROSIL R202 as hydrophobic silica according to this invention and other additives in the amounts as shown in Table 1. In the same manner as in Comparative Examples 1-3, set- ting time of these compositions for beechwood and stringing property thereof were measured and the re- sults are shown in Table 1. EXAMPLES 1-4 Four compositions were prepared which contained 15-crown-5 and AEROSIL R972, AEROSIL R805, AEROSIL R202 or Cab-O-Sil N70-TS and other addi- tives in the amounts as shown in Table 1. Each setting time of these compositions for beechwood was mea- sured in the same manner as in the above comparative examples to obtain 20 seconds, 15 seconds, 15 seconds and 15 seconds, respectively. Furthermore, as in the comparative examples, the compositions were heated at 60° C. for 10 days and setting time of the compositions for beechwood and stringing property thereof were measured to obtain 30 seconds, 20 seconds, 20 seconds and 20 seconds, respectively for setting time and 1 cm, 0 cm, 0 cm and 0 cm, respectively for stringing. Thus, no problems were found. EXAMPLES 5-9 Five compositions were prepared which contained AEROSIL R972 as hydrophobic silica and 18-crown-6 or the like and other additives in the amounts as shown in Table 1. These compositions were subjected to the same tests as in the comparative examples to find some delay in setting time and some increase in stringing, but these were such that caused no special problems. _ TABLE 1 Composition Stability Thickening Hydrophobic Setting time (60° C., 10 days) 2-Cyanoacrylate agent (part Stabilizer Crown ether, silica (part (Beechwood/ Setting (part by weight) by weight) (ppm) etc. (ppm) by weight) Beechwood) time Stringing Comparative Ethyl 2-cyano- PMMA S02 (40) 15-Crown-5 none 30 sec 45 sec 10 cm Example 1 acrylate (97) (3) HQ (1000) (100) Comparative Ethyl 2-cyano- PMMA S02 (40) 18-Crown-6 none 30 sec 45 sec 10 cm Example 2 acrylate (97) (3) HQ (1000) (100) Comparative Ethyl 2-cyano- PMMA S02 (40) PEG#400 none 30 sec 60 sec 20 cm Example 3 acrylate (97) (3) HQ (1000) (1000) Comparative Ethyl 2-cyano- PMMA S02 (40) none AEROSIL R972 > 180 sec >180 sec 1 cm Example 4 acrylate (87.3) (2.7) HQ (1000) (10) Comparative Ethyl 2-cyano- PMMA S02 (40) none AEROSIL R805 >180 sec >180 sec 0 cm Example 5 acrylate (92.15) (2.85) HQ (1000) (5) Comparative Ethyl 2-cyano- PMMA S02 (40) none AEROSIL R202 > 180 sec >180 sec 0 cm Example 6 acrylate (92.15) (2.85) HQ (1000) (5) _ Comparative Ethyl 2-cyano- PMMA S02 (40) none AEROSIL R202 60 sec 90 sec 10 cm Example 7 acrylate (92.lS)* (2.85) HQ (1000) (5) Example 1 Ethyl 2-cyano- PMMA S02 (40) 15-Crown-5 AEROSIL R972 20 sec 30 sec 1 cm acrylate (87.3) (2.7) HQ (1000) (100) (10) Example 2 Ethyl 2-cyano- PMMA S02 (40) 15-Crown-5 AEROSIL R805 15 sec 20 sec 0 cm acrylate (92.15) (2.85) HQ (1000) (100) (5) Example 3 Ethyl 2-cyano- PMMA S02 (40) 15-Crown-5 AEROSIL R202 15 sec 20 sec 0 cm acrylate (92.15) (2.85) HQ (1000) ( 100) (S) ‘ 4,837,260’ 9 10 TABLE 1-continued Composition Stability Thickening Hydrophobic Setting time g60° C., 10 days) 2-Cyanoacrylate agent (part Stabilizer Crown ether, silica (part (Beechwood/ Setting (part by weight) by weight) (ppm) etc. (ppm) by weight) Beechwood) time Stringing Example 4 Ethyl 2-cyano- PMMA S02 (40) 15-Crown~5 Cab-0-Sil 15 sec 20 sec 0 cm acrylate (92.15) (2.85) HQ (1000) (100) N70-TS (5) Example 5 Ethyl 2-cyano- PMMA S02 (40) 18-Crown-6 AEROSIL R972 20 sec 30 sec 1 cm acrylate (87.3) (2.7) HQ (1000) (100) (10) Example 6 Ethyl 2-cyano- PMMA S02 (40) PEG#40O AEROSIL R972 20 sec 30 sec 1 cm acrylate (87.3) (2.7) HQ (1000) (1000) (10) Example 7 Ethyl 2-cyano- PMMA S02 (40) Polyoxy- AEROSIL R972 30 sec 45 sec 2 cm acrylate (87.3) (2.7) HQ (1000) ethylene (10) monostearate (2000) Example 8 ' Ethyl 2-cyano- PMMA S02 (40) Polyoxy- AEROSIL R972 30 sec 45 sec 3 cm acrylate (87.3) (2.7) HQ (1000) ethylene (10) dimethacry- late (5000) Example 9 Ethyl 2-cyano- PMMA S02 (40) Polypropylene AEROSIL R972 45 sec 60 sec 3 cm acrylate (87.3) _ (2.7) HQ (1000) glycol (10) (5000) ‘S000 ppm of dimethylsilane-17-crown-6 was added Thixotropic index (T.I.) was calculated by the fol- EXAMPLES 10-22 AND COMPARATIVE lowing equation EXAMPLES 8-9 . 25 Compositions were prepared by mixing with stirring Viscosim £025. 6 RPM 0, 5 RPM) the components at the ratio as shown in Table 2 and T1‘ = Viscosity (cps. 60 RPM or 50 RPM) performances of the compositions as adhesives were measured. The results are shown in Table 2. Bonding speed: The properties show‘: in Table 2 were measured by 30 Setting time for hard PVC and beech woods at 23° C. the following methods. ' - and 60% RH was measured according to JIS K6861. Viscosity: Bonding strength: Viscosity was measured by brookfield viscometer BL Tensile bond strength for hard PVC at 23° C. and type with rotor No. 4 and at 6 RPM and 60 RPM or 60% RH was measured according to JIS K6861. B8H type with rotor No. 7 and at 5 RPM and 50 RPM 35 Stability test: at 25° C. 3 g of the adhesive was charged in an aluminum tube and subjected to heating test of 70° C. X7 days to exam- ine thickening, gelation and stringing. TABLE 2 Thick- 2-Cyano- ening Vis- Bonding acrylate agent Stabilizer Hydrophobic Crown ether, cosity Setting Strength ' (wt %) (wt %) (ppm) silica (wt %) etc. (ppm) (cps) T.I. time (Kgf/cmz) Stability Example 10 Ethyl PMMA S02 (40) AEROSIL » PPG#4000 86,600 7.52 3 sec 340 Acceptable (89) (4) HQ (1000) 2974 (5000) (PVC) Com- Ethyl PMMA S02 (40) AEROSIL — 1,000 — — — — parative (89) (4) HQ (1000) R974 Example 8 (7) ' Example 11 Ethyl PMMA S02 (40) AEROSIL PPG#4000 36,000 6.25 3 sec 330 Acceptable (89.1) V (4) HQ (10()0) $891; (5000) - (PVC) Com- Ethyl PMMA S02 (40) AEROSIL ’ — 7,800 4.49 —- - - parative (89.1) (4) HQ (1000) R811 Example 9 (6.9) Example 12 Ethyl PMMA S02 (40) AEROSIL PTMG#2000 124,000 7.31* 3 sec 360 Acceptable (89) (4) HQ (1000) R7974 (SO00) (PVC) Example 13 Ethyl PMMA S02 (40) AEROSIL PEG#400 44,200 5.42 3 sec 320 " (88) (4) HQ (1000) R811 (1000) (PVC) (8) 30 sec (beech) Example 14 Methyl PMMA S02 (40) AEROSIL PPG/PEG 125,000 7.20‘ 3 sec 330 " (88) (4) HQ (1000) R972 block (PVC) (8) copolymer 30 sec (3000) (beech) Example 15 Isobutyl CAB S02 (40) AEROSIL PPG#1000 75,000 7.80 5 sec 295 ” (88) (5) HQ (1000) R972 (5000) (PVC) (7) Example 16 Ethoxyethyl CAB S02 (40) AEROSIL PPG#2000/T D1 187.000 8.20‘ 5 sec 300 " (86) (5) HQ (1000) R972 (1/1.5 molar (PVC) ' (9) ratio reaction product) (6000) Example 17 Ethyl PMMA SO2(40) AEROSIL PEG#400 11,300 4.65 3(PVC)_ 330 ” 4,837,260 11 12 TABLE 2-continued Thick- 2-Cyano- ening Vis— Bonding acrylate agent Stabilizer Hydrophobic Crown ether, cosity Setting Strength (wt %) (wt %) (ppm) silica (wt %) etc. (ppm) (cps) T.l. time (Kgf/cml) Stability (89) (4) HQ (1000) R974 (4600) 20 (7) (Beech) Example 18 Ethyl PMMA S03 (40) AEROSIL PEG#6000 125,000 592* 3>(PVC) 350 " (39) (4) HQ (1000) R974 (4600) 20 (7) (Beech) Example 19 Ethoxyethyl CAB S02 (40) AEROSIL PPG#1000 128,800 5.67* 5 (PVC) 300 ” (87) (5) HQ (1000) R811 (4000) 30 (8) PEG (Beech) monostearate (1000) Example 20 Ethyl PEA PTS (10) AEROSIL PTMG#2000 85,000 6.20‘ 3 (PVC) 340 " (89.5) (35) HQ (1000) R810 (2000) 20 (7) PEG#1000 (Beech) (1000) Example 21 Ethyl/butyl CAB PTS (10) AEROSIL PTMG#l00O 175,000 7.80* 3 (PVC) 310 ” (50/50) (4) HQ (1000) R976 (3000) . 20 (88) ‘ (8) PEG#600 (Beech) dimethacrylate (1000) Example 22 Ethyl PMMA S02 (20) AEROSIL PPG#400 13,400 5.92 3 (PVC) 325 ” (90) (4) HQ ( 1000) R974 (4600) 20 (6) 18-crown-6 (Beech) 0.04 (400) ‘Measured at 5 RPM PMMA: Polymethyl methacrylate. PEA: Polyethylacrylate. CAB: Celluloseacetate butyrate, PEG: Polyethylene glycol. PPG: Polypropylene glycol. PTMG: Po|ytetra- methylene glycol EXAMPLES 23-3-1 Eight parts by weight of each surface treating agent as shown in Table 3 was diluted by 12 parts by weight of hexane. Each of the solutions of the surface treating agents in hexane was dropped to 20 parts by weight of fumed silica AEROSIL 200 having surface area of 200 m2/g with stirring. After having been stirred for 30 minutes, each mixture was heated at 110° C. for 1 hour under nitrogen atmosphere to remove hexane and pro- duce a powder. Each resultant powder was put into a flask equipped with a reflux condenser, a stirrer and a thermometer and then was heated with stirring at 250° C. for 4 hours to yield hydrophobic silicas A to G as shown in Table 3. 30 35 40 45 The hydrophobicity of the resultant hydrophobic silicas was evaluated using their wettings to a solution of water and methanol, which was measured as follows: Fifty milliliters of distilled water is poured into a 200ml beaker. And after 0.2 gram of hydrophobic silica has been put onto the water in the beaker, methanol is introduced into the water through an outlet of a burette immersed in the water with stirring using a magnetic stirrer. The amount X in milliliter of methanol which has been added until the floating silicas are wetted with the solution of water and methanol, is measured. Then, hydrophobicity is obtained by the following equation: Hydrophobicity = 100 X / (50+X). Nine types of adhesives were prepared using hydro- phobic silicas A to G in Table 3. The properties of the obtained adhesives are shown in Table 4 together with their formulations. TABLE 3 A list of hydrophobic silicas prepared in Examples 23-31 Samples Surface treating agents » Specific surface obtained Silicas to be treated (Conc. used, %) area (m2/g) hydrophobicity A AEROSIL 200 Trimethoxyvinylsilane 166 30 (product of Japan (20) Aerosil Co.) B AEROSIL 200 Dimethoxymethylvinyl- 159 35 (product of Japan silane Aerosil Co.) (20) C AEROSIL 200 Divinyltetramethyl- 147 60 (product of Japan disilazane Aerosil Co.) (20) D AEROSIL 200 Aryltriethoxysilane 166 30 (product of Japan (20) Aerosil Co.) E AEROSIL 200 Phenyltrimethoxysilane 184 40 (product of Japan (20) Aerosil Co.) F AEROSIL 200 Polymethylphenyl- 122 35 . (product of Japan siloxane Aerosil Co.) (20) G AEROSIL 200 Methyltrimethoxysilane 157 30 (product of Japan (20) 4,8 13 TABLE 3-continued 37,260 A-list of hydrophobic silicas prepared in Examples 23-31 Surface treating agents (Cone. used. %) Samples Specific obtained Silicas to be treated Aerosil Co.) area (m2/ g) surface TABLE 4 . Examples 23-31 hydrophobicity 14‘ Polymeri- _ 2-Cyano- zation Hydrophobic Viscosity Setting Bonding acrylate Thickening inhibitors silicas Crown ether, (Rotor time strength (wt %) agent (wt %) (ppm) (wt %) etc. (wt %) No. 2) T.I. (sec) (kgf/cmz) Stability Example 23 Ethyl PMMA(3) SOz(40) A(5) PEG #400 12000 5.1 3 340 Acceptable (91.5) HQ(l00O) (0.5) Example 24 Ethyl PMMA(3) SO1(40) A(5) PEG #6000 58300 6.8 3 360 ” (91.5) I-IQ(l000) (0.5) Example 25 Ethyl PMMA(3) SO2(40) A(5) PPG #2000 53100 7.1 3 360 " (91.5) I-IQ(l0OO) (0.5) Example 26 Ethyl PMMA(3) SO3(40) A(5) PTMG #2000 . 66200 7.3 5 320 " (91.5) . I-lQ(lOOO) (0.5) Example 27 Methyl PMMA(3) SO2(40) B(5) PPG #2000 51000 6.8 3 340 " (91.5) HQ(l000) (0.5) Example 28 Ethyl PMMA(3) SO2(40) C(5) PPG #2000 ' 48300 6.5 3 340 " . (91.5) HQ(l000) (0.5) Example 29 lsobutyl CAB(3) SO2(40) D(5) PPG #2000 55200 7.2 3 330 " (91.5) I-lQ(l000) (0.5) Example 30 Ethyl PMMA(3) SO2(40) E(5) PPG #2000 46000 6.7 3 320 ” (91.5) HQ(1000) (0.5) Example 31 Ethyl PMMA(3) SOz(40) F(5) PPG #2000 52500 6.6 3 320 " (91.5) HQ(1000) (0.5) The compositions of this invention provide cyanoac- rylate adhesives which can easily bond woods, papers, leathers, etc. which have been difficult to bond with cyanoacrylate adhesives. The adhesives obtained in this invention have a high bonding speed, are free from stringing and excellent in storage stability, and thus can be used in both the industrial and household fields. The effects of this invention are remarkable. Furthermore, the compositions of this invention are also excellent as molding agents for fiber reinforced materials and finger- 35 print detecting agents and thus use of 2-cyanoacrylate 45 can be extended. What is claimed is: 1. A cyanoacrylate composition which comprises a 2-cyanoacrylate as a main component and at least one of (A) crown ethers, polyalkylene oxides and polyalkylene 50. oxide derivatives and at least one of (B) hydrophobic silicas. 2. A composition according to claim 1 wherein the crown ethers are macrocyclic polyethers where the heteroatoms are oxygen. 3. A composition according to claim 1 wherein the polyalkylene oxides have a polymerization degree of at least 2. 4. A composition according to claim 3 wherein the polyalkylene oxides have a molecular weight of 400-1,000,000. 5. A composition according to claim 1 wherein the alkylene group of the polyalkylene oxide has 2-6 car- bonatoms. 55 60 65 6. A composition according to claim 5 wherein said alkylene group is ethylene, propylene, isopropylene, tetramethylene or a combination thereof. 7. A composition according to claim 5 wherein said alkylene group is propylene, tetramethylene or a combi- nation thereof. 8. A composition according to claim 1 wherein the polyalkylene oxide derivatives are esters of the polyal- kylene oxide with acids or ethers with hydroxyl group- containing compounds. 9. A composition according to claim 1 wherein the hydrophobic silicas are those obtained by converting the surface of a hydrophilic silica to a hydrophobic surface by treating the surface of the hydrophilic silica with a surface treating agent. ’ 10. A composition according to claim 7 wherein the hydrophilic silica is fumed silica or wet silica. 11. A composition according to claim 9 wherein the surface treating agent is a dimethylsilylating agent or a trimethylsilylating agent. 12. A composition according to claim 1 wherein the amount of component (A) is 0.0001—20 parts by weight for 100 parts by weight of 2-cyanoacrylate. 13. A composition according to claim 1 wherein the amount of component (B) is l-30% by weight of the composition. 14. A cyanoacrylate adhesive which comprises the composition of claim 1. 15. A cyanoacrylate composition according to claim 12 which additionally contains an anionic polymeriza- tion inhibitor, a radical polymerization inhibitor and a thickening agent. 16. A composition for shaping materials which com- prises the composition of claim 1. * * ll‘ * =1: