Cyanoacrylate Esters

PATENT SPECIFICATION NO DRAWINGS 1,048,906 Inventors: BENJAMIN DAVID HALPERN, JACK DICKSTEIN, and ROSE-MARIE HOEGERLE Date of Application and filing Complete Specification: july 23, I 964. No. Z9684/64. Complete Specification Published: Nov. 23, I966. © Crown Copyright I966. 1.0-48,906 Index at acceptance :—C2 021320; 03 P(4A, 4014B, 4C17, 4C20C‘, 4D3B1, 4K8, 4P1D, 4P1E1, 4P1E5, 4P3, 4P5, 4T2A, 7A, 7C14B, 7C17, 7C20C, 7D2-‘A1, 7D21A2B, 7K8, 7P1D, 7P1E1, 7P1E5, 7P3, 7P5, 7T2A., 8A, 8C14B, 8C17, 8C20C, 8D2A, 8D2B2, 8D2B3, SD5, 8K4, 8K7, 8K8, 8K10, 8P1D, 8P1E1, 8P1E5, SP3, SP5, 8T2A, 10A, 10C14B, ZLOC17, 10C20C, 10D1A, 10K8, 10P1D, 10P1E1, 10PlE5, 10P3, 1OP5, 10T2A) ; C3 R27K8D Int. o1.:_0 07 c 121/30 // C 08 f, g COMPLETE SPECIFICATION Cyanoaerylate Esters _We, THE BORDEN COMPANY, a corpora- ethylenic bond which makes possible poly- tion organised under the laws of the State of merisation and cross-linking. 15 New Jersey, United States of America, of The present invention provides compounds 350, Madison Avenue, New York, State of of the formula 5 New York, United States of America, do CH2 hereby declare the invention, for which we pray that a patent may be granted to us, and NC—C-—COOR the method by which it is to be performed, to be particularly described in and by the wherein R represents one of the radicals 10 following statement : — This invention relates to cyanoacrylate CH2 esters. H 20 These esters have the special feature of an —CH2—CH2OOC—G—CN CH2 ll —-(CH2—CI-I._.—O—CH2—CH2)xOOC—C-—CN or by weight thereof with 1 to 9 parts by weight CH3 of vinyl chloride, vinyl acetate, methyl acrylate, ethyl acrylate, methyl methacrylate, —CH2—C—CH-_»—OOC—C—CN ethyl methacrylate, styrene and/or vinyl I toluene. 30 CH3 The present invention, thereof, comprises the new cyanoacrylates illustrated in the wherein X is a number from 2 to 30, homo- following Table I and provides also adhesives 25 polymers thereof and copolymers of 10 parts made from these compounds. 10 15 20 45 50 55 1,048,906 TABLE I Compound Name Ethylene glycol 2,2 '- dicyanoacrylate Dicyanoacrylates of polyethylene glycol Formula CH. CH.. H H NC—C—-COOCH2CH2OOC—C—CN cH._. ll NC--C-COO(C2H,,—O—-C._.H.,)::c— CH2 :1 OO C—C—CN Neopentyl glycol 2,2-dicyanoacrylate CH2 Ion, CH, H {I NC—C——COOCH2-C-CH20OC—C—CN I CH3 Here x is a number from 2 to 30. The invention provides also adhesive com- positions comprising a solution of one part by weight of any of the materials set out above in 2 to 10 parts by weight of a volatile, chemically inert solvent. These compounds are made as shown in the following Examples. Except where specifically stated to the contrary, all dryings are carried out over anhydrous magnesium sulphate at room temperature and all pro- portions are expressed by weight. EXAMPLE 1. Ethylene Glycol Dicyanoacrylate. Ethylene glycol dicyanoacetate was first made as follows: A mixture of 190 g. of cyanoacetic acid, 62 g. of ethylene glycol, 5 g. of p-toluene- sulphonic acid and 440 g, of anhydrous benzene were boiled under reflux with con- Analysis, 7, calcd. for C,H,.N;.0,,: C, 4 . 4 Found. 1 mole of the ethylene glycol dicyanoacetate so made was then mixed with 2 moles of formaldehyde and condensed, in benzene solu- tion in contact with 0.2 mole of zinc acetate dihydrate as condensing agent and boiled for 1 hour. The water formed in the condensa- tion was distilled ofl and collected in a water trap. The benzene was removed by boiling under atmospheric pressure. The residue remaining was then washed with three separate portions of dioxane and thus separated from impuri- ties preferentially soluble in the dioxane. tinuous stirring for 10 hours. During this period, the theoretical amount of water was formed, distilled away and collected in a water trap. As the dicyanoacetate ester formed, the benzene separated. The benzene was removed by distillation under reduced pressure and replaced by 1,000 g. of methylene dichloride. The resulting solution was washed with saturated aqueous potassium bicarbonate solution and then with water. The washed liquid that remained was dried and filtered and the volatile material was distilled off. The oily residue that remained was first dried under 12 mm. pressure and subsequently for 4 hrs. under 0.5 mm. pres- sure, yielding 170 g. of colourless crystals of ethylene glycol dicyanoacetate of m.p. 37°—— 40° C. Recrystallisation from methanol gave thin needles of m.p. 41°—45° C_ and b.p. 210° C. at 2 mm. .0 The residue so washed was dried as above. The residue was ethylene glycol 2,2’-dicyano- acrylate. For use as an adhesive, the ethylene glycol dicyanoacrylate is dissolved in a solvent therefor, e.g., a volatile ketone such as acetone, methyl ethyl ketone or mixtures thereof, as in the proportion of 1 to 10 parts of the ketone for 1 part of the cyanoacrylate. EXAMPLE 2. Polyethylene glycol dicyanoacrylate. The composition and procedure of Ex- ample 1 were followed except that the 25 30 35 40 60 65 1,048,906 l0 l5 ethylene glycol there used was replaced, first, by an equimolecular proportion of diethylene glycol, so that the intermediate compound first formed was diethylene glycol dicyano- acetate. This was then condensed with form- aldehyde and processed as described in Ex- ample 1. In a modification of this Example, the di- ethylene glycol was replaced by an equimolar weight of another polyethylene glycol, as for example by glycol 400 and glycol 1000, used separately and in turn. The products are alpha-acrylates of the polyglycols, and have cross-linking properties because of their di- functional nature. cesses of Examples 1 and 2, of using dilferent inhibitors of polymerisation of ethylenic bonds added during the formation of the di- cyanoacrylate esters and of different atmospheres under which the mixture was maintained during the condensation. It shows also the amount of water separated from the trap during the condensation, as a percentage of the theoretical maximum for a perfect yield of condensed product, the reaction time in hours, and the physical nature of the finished glycol 2,2’-dicyanoacrylate which undergoes, to some extent, polymerisation of the carbon-to-carbon double bonds. In this table the zinc acetate, when used, was the di- hydrate. In two instances the zinc acetate was 20 25 30 35 EXAMPLE 3. used in combination with acetic acid (ACOH) Condensing Agents. as shown. The abbreviations “DEG” and The following Table II shows the effect “EG” represent diethylene glycol and of using various condensing agents in the pro— ethylene glycol, respectively. TABLE II Atmosphere Water Reaction Nature Glycol Condensing During Sep. % Time, of End used Agent Inhibitor Condensation of theory Hours Product DEG — t—butyl N2 67 5 Rubbery mass catechol ,, Zn(0Ac)2—Ac0H — air 87 0.75 Highly viscous oil ,, Piperidine S02 S02 24 2.0 Hard, White Solid precipitate ,, Piperidine — air 48 2.0 Polymeric gel acetate EG Zn(OAc) 2 — air 72 0 .75 Orange red gel ,, Zn(OAc)2—AcOH — air 25 1.30 Hard, rubbery ,, Piperidine —- air 0.5 0.10 Hard, white acetate polymeric :_:. 45 50 55 These esters of the glycols are adhesives. They are suitable for application to glass, paper or aluminium foil, for example in a solution of 20 parts of the esters for 100 of a volatile ketone solvent. EXAMPLE 4. Neopentyl glycol 2,2’—dicyanoacrylate. A mixture of 52 g. of neopentyl glycol, 94 g. of cyanoacetic acid, 2 g. of p-toluene- sulphonic acid and 265 g. of benzene were heated under reflux for 17 hours, during which the theoretical amount of water was distilled off azeotropically. The remaining mixture had only one phase. It was washed with aqueous potassium carbonate solution, dried, and filtered. On distilling ofi the solvent, a colourless oily residue was obtained which did not crystallise after several hours of further drying under 0.5 mm. pressure at room temperature. 113 g. of neopentyl glycol dicyanoacetate were isolated. The infrared absorption spectrum showed that there was no cyanoacetic acid remaining in the product. 11.9 g. of this neopentyl glycol dicyano- acetate was added gradually to 3.5 g. of para- formaldehyde in 44 g. of benzene, contain- ing 3 drops of piperidine, at 75° C. A colour- less precipitate separated immediately. After boiling for 6.5 hr., 1.9 g. of water (100% of theory) had separated in the water trap. The 60 65 70 10 I5 20 25 30 60 4 1,048,906 residue of the reaction mixture was filtered, washed several times with benzene and dried, yielding 13.0 g. of neopentyl glycol 2,2’-di- cyanoacrylate with a decomposition range of 240°,—295° C. and of only very slight solu- bility in chloroform, benzene, acetone, methyl ethyl ketone and ethyl acetate. Infrared absorption spectrum: 22[50 cm“‘ (C=N); 1620, 940, 865 cm"1 The neopentyl 2,2’-dicyanoacrylate is un- usually resistant to decomposition by heat. EXAMPLE 5. Cross—Linking, The cyanoacrylate esters described herein undergo cross-linking more rapidly at elevated temperatures, for example, 80 to 150° C. to accelerate the rate of cross-linking or to lower the temperature used, an initiator, such as any of the percompounds commonly used to initiate polymerisation of ethylenic double bonds, e.g., sodium or potassium per- sulphate, benzoyl peroxide and azobisiso- butyronitrile, may be incorporated, advan- tageously from 0.5% to 1% of the percom— pound based on the dry weight of the di- - cyanoacrylate. In a modification of this Example, the cyanoacrylate esters that are the final products ' of each of the Examples 2, 3 and 5 are co- polymerised with an comonomer containing an ethylemc double bond, e.g., vinyl chloride, vinyl acetate, methyl or ethyl acrylate or methacrylate, styrene, or vinyl toluene, in the proportion of 1 to 9 parts by weight of the combined cyanoacrylate and the comonomer, and with 10°/,, of any of the initiators set out above, on the total weight, at 100° C. To make an adhesive, the final product of any of the Examples 1 to 5 is dissolved in any anhydrous and chemically inert solvent therefor, of which N,N-dimethylformamide is an example. Proportions of the solvent that are suitable are 2 to 10 parts by weight for 1 part by weight of the final product. The adhesives made as described herein are applied to the surface to be bonded and main- tained at a such a temperature as will give setting of the adhesive at the desired rate. For most purposes either no warming or only moderate warming is required. WHAT WE CLAIM IS:— 1. Compounds of the formula tea I NC—C—COOR wherein R represents one of the radicals CI-I2 ll —CH2—CH2OOC—C—-CN CH. H or CH3 I H —CHg—C-—CH2—O0C—C—CN I CH3 CH2 wherein x is a number from 2 to 30, homo- polymers thereof and copolymers of 10 parts by weight thereof with 1 to 9 parts by weight of vinyl chloride, vinyl acetate, methyl acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate, styrene and/or vinyl toluene. 2. Ethylene glycol 2,2’-dicyanoacrylate. -3. Polyethylene glycol 2,2’-dicyanoacrylate containing 2 to 30 polyethylene glycol units per molecule. 4. Neopentyl glycol 2,2’-dicyanoacrylate. 5. Compounds as claimed in claim 1 sub- stantially as described with reference to any of the Examples. 6. An adhesive composition comprising 1 part by weight of a compound or compounds as claimed in any of the preceding claims in Z to 10 parts by weight of a volatile, chemically inert solvent. ELKINGTON & FIFE, Chartered Patent Agents, High Holbom House, 52-54, High Holbom, London, W.C.1, Agents for the Applicants. Leamington Spa: Printed for Her Majesty's Stationery Office, by the Courier Press (Leamington) Ltd.—1966. Published by The Patent Ofi'ice, 25 Southampton Buildings, London, W.C.2, from which copies may be obtained. ...u 35 40 45 50 55 70 75