GB2200909A - Cyclophanes - Google Patents

Abstract

Novel polyalkyleneglycol cyclophanes are added to adhesive compositions as adhesion promoters. The cyclophanes have the following general formulae:- <IMAGE> wherein R is (-R<2>-O)mR<3>, in which R<2> is substituted or unsubstituted alkyl with 2 to 6 carbon atoms, m is an integer of from 2 to 3000 and R<3> is alkyl, aryl, alkaryl or substituted derivatives thereof; R<1> is hydrogen, hydrocarbyl, aryl, hydrocarbylaryl or a halogen selected from fluorine, chlorine, iodine or bromine; and n is 4 to 8.

Description

POLYALKYLENEGLYCOL FUNCTIONAL CYCLOPHANES AS POROUS BONDING CYANOACRYLATE ADDITIVES" The present invention relates to additives for cyanoacrylate-based adhesive compositions which promote adhesion to wood, paper and other substrates with a porouslacid surface. The invention also relates to adhesive compositions comprising the said additive.

Cyanoacrylate-based adhesives can be used to firmly bond a wide variety of materials in an extremely short time. These adhesives are cured by anionic polymerization which is initiated by the presence of a weak anion, such as a slight amount of water present on the substrate.

However, when cyanoacrylate-based adhesives are used on wood, paper or substrates with porous/acid surfaces, anionic polymerization is inhibited despite the high moisture content of these substrates. This lengthens the setting time. Furthermore, during this time the adhesive composition penetrates into the porous surfaces of the substrate and adhesive-free portions in the adhesive layer result, thus impairing the strength of the adhesive joint.

Various attempts have been made to reduce the setting time of cyanoacrylate-based adhesives on wood and other porous materials.

DE-OS 2,816,836 proposes the use of a macrocyclic polyether compound, chosen from the group of macrocyclic polyethers and their analogs, as a polymerization catalyst. However, there are problems with the synthesis of such compounds.

U.S. Patent No. 4,170,585 proposes the use of from 0.0001 to 20% by weight of at least one of a polyethylene glycol with a degree of polymerisation of at least 3, or a non-ionic surfactant with a polyethyleneoxy content and a degree of polymerization of at least 3.

These compounds have the disadvantage that they have a great tendency to contain water and low molecular weight polyethylene glycol ether which are difficult to remove and spontaneously initiate polymerization when the compounds are added to cyanoacrylates.

United Kingdom Patent Specification No. 2,075,522A suggests, as polymerization catalysts, polyethylene glycol derivatives of formula:

in which A is a group linking the Xs by a one or two atom bridge; B is a tetravalent atom eg. carbon or silicon, R is a C1 - C12 hydrocarbon group free of hydroxy or amino groups; R' is hydrogen or a lower alkyl group; R2 is a lower alkyl; X and Y are oxygen or may be sulphur or -N-CH3 in compounds containing group A, and n: m p and q each represent a whole integer.

U.S. Patent No. 4,377,490 suggests the use of adhesive compositions for such substrates which comprise (i) an alphacyanoacrylate ester, (ii) at least one chosen from aliphatic polyols and heir derivatives and polyethers and their derivatives and (iii) at least one chosen from aromatic polyols and their derivatives and carboxylic acids and their derivatives.

According to the present invention there are provided novel cyclophanes of the following general formulae:

wherein R is (-R2-O)R3, in which R2 is substituted or unsubstituted alkyl with 2 to 6 carbon atoms, m is an integer of from 2 to 3000 and R3 is alkyl, aryl, alkaryl or substituted derivatives thereof; R' is hydrogen, hydrocarbyl, aryl, hydrocarbylaryl or a halogen selected from fluorine, chlorine, iodine or bromine; and n is 4 to 8.

Preferably m is an integer of from 3 to 6. Hydrocarbyl is suitably alkyl or alkenyl, especially having 1 to 10 carbon atoms, more particularly having 1 to 5 carbon atoms.

The present invention also relates to cyanoacrylate adhesive compositions including as an accelerator a cyclophane of formula I :

or of formula II

wherein R, R' and n are as defined above.

The compounds of formulae I and II are useful as adhesion promoting accelerators in alpha-cyanoacrylate compositions for bonding wood or other de-activating surfaces such as paper, leather, ceramic, plastics and metals with chromate-treated or acidic oxide surfaces. The inventive compositions are standard cyanoacrylate adhesive formulations to which have been added, as accelerators, cyclophane compounds as described above which are stable to cyanoacrylate monomers. The cyclophane compounds are employed in amounts conventional for cyanoacrylate accelerators, preferably at levels between about 0.1% and 5% by weight of the composition.

The standard cyanoacrylate compositions are as described in U.S. Patent No. 4 556 700, Harris et al at column 2, line 18 to column 3, line 32; the contents of which are incorporated herein by reference.

Calixarene compounds may be readily synthesised by methods described in C. Gutsche, Acc. Chem. Res. 16, 161-170 (1983) and references cited therein; U.S. Patent No. 4 556 700, Harris et al; and in J. Inclusion Phenomena 2 199-206 (1984) D Reidel Publishing Company; the appropriate disclosures of all of which are incorporated herein by reference.

Cyclotriveratrylene compounds may be synthesised as described in J.A.

Hyatt, J. Org. Chem. 43 1808-1811 (1978), the contents of which are included herein by reference.

EXAMPLE 1 Preparation of Ethvl Ether of Triethvleneqlycol of o-t-Butvicalix-8-arene The tosylate of the ethyl ether of triethyleneglycol was prepared by reacting the alcohol with 1.1 equivalents of p-tosyl chloride in dry pyridine as a pale yellow oil following the procedure of J.A. Hyatt. J.

Org. Chem. 43 (9) p 1808 1978. To 0.97g (0.00075 mole) of p-t-butylcalix-8-arene in 10ml of dry N-methyl pyrrolidone was added 2.65 g (0.0080 mole) triethylene glycol monoethyl ether p-toluenesulphonate and the reaction mixture was stirred under nitrogen at room temperature for four hours. After this time 0.168g (0.0070 mole) sodium hydride was added to the reaction mixture and the entire was heated for 17hr at 90CC under nitrogen with rapid stirring.

After cooling to room temperature N-methyl pyrrolidone was distilled off under reduced pressure to give a brown sticky solid residue. To this residue was added 20ml dichloromethane and the solid was filtered off to give a clear red brown filtrate which was washed three times with 20 ml of 10% aqueous H2 504 and once with water following which it was dried over MgSO4. Following solvent removal 1.40g pale red-brown oil product remained, 70% of which on standing partly solidified. The product was chromatographed on acid-washed alumina using dichloromethane as eluent to give a pale yellow brown oil which again partly solidifed on standing. Infra-red spectroscopy revealed it to be the monoethyl ether of triethyleneglycol of p-t-butylcalix-8-arene.

I.R. spectroscopy results: i 1120 cm-1(S) C-O-C (no 3320 cm-l due to C-OH).

EXAMPLE 2 Preparation of Ethvl Ether of Triethvlenealvcol of P-T-Butvlcal ix-4-arene The same procedure as for the p-t-butylcalix-8-arene was followed.

From 0.97g (0;00150 mole) p-t-butylcalix-4-arene we obtained 1.78g of the monoethyl ether of triethyleneglycol of p-t-butylcalix-4-arene (89% yield) as a pale yellow-brown oil. Chromatography on acid washed alumina using dichloromethane as eluent afforded pure product as a pale yellow viscous oil whose structure was confirmed by infra-red spectroscopy.

I.R. spectroscopy results:1) 1110 cm-l(S) C-O-C (no 3320cm-l due to C-OH) EXAMPLE 3 PreDaration of Ethvl Ether of Triethyleneolycol of Hexaol of Cyclotriveratrvlene.

Cyclotriveratrylene was demethylated with boron tribromide following the procedure of Lindsey (A.S. Lindsey. J. Chem. Soc. p 1685, 1965) to give the colourless hexaol. 0.559.(0.00150 mole) of hexaol was added to 3.93g (0.0118 mole) of triethylene glycol monoethyl ether p-toluenesulphonate in 10ml dry N-methyl pyrrolidone and the reaction mixture was stirred-under nitrogen at room temperature for four hours.

After this time 0.3369 (0.014 mole) sodium hydride was added to the stirred reaction mixture and the entire was heated to 90 0 C for 4 hours following which N-methyl pyrrolidone was removed at reduced pressure leaving a red-brown sticky solid residue. To this was added 20ml dichloromethane and the entire was filtered to give a clear brown filtrate from tich all volatiles were removed to give 2.199 (100%) product as a pale yellow-brown oil. The crude product was chromatographed on acid-washed alumina using dichloromethane as eluent to give pure product as a pale yellow-brown oil whose structure was confirmed by infra-red spectroscopy.

I.R. spectroscopy results: ;) 1130cm-1(S) C-O-C (No 3320cm-l due to C-OH) EXAMPLE 4 Ethyl cyanoacrylate stabilised with 10 ppm BF3 was used as a base adhesive formulation. The polyethylene glycol ethyl ethers of the calixarenes and hexaol of cyclotriveratrylene (Examples 1 - 3) were dissolved in the base adhesive at the levels indicated in Table 1 and fixture times on white deal and copy paper were determined. The results shown below demonstrate the good accelerative activity of these materials: TABLE 1 Additive Amount Fixture Time O CoDv Paper White Deal 0 0 60 seconds 5-6 minutes Example 1 1% 60 seconds 60-90 seconds Example 2 1% 60 seconds 4-4.5 minutes Example 3 1% 40 seconds 60-90 seconds CH3CH2O(CH2CH2O)3H 1% 60 seconds 2.5-3 minutes Triethyleneglycol monoethyl ether (Comparative Example)

Claims (7)

1. CLAIMS 1. Cyclophanes of the following general formulae:

   wherein R is (-R2-O)R3, in which R2 is substituted or unsubstituted alkyl with 2 to 6 carbon atoms, m is an integer of from 2 to 3000 and R3 is alkyl1 aryl, alkaryl or substituted derivatives thereof; R1 is hydrogen, hydrocarbyl, aryl, hydrocarbylaryl or a halogen selected from fluorine, chlorine, iodine or bromine; and n is 4 to 8.
2. 2. A cyclophane as claimed in claim 1 wherein hydrocarbyl is alkyl or alkenyl having l to 10 carbon atoms.
3. 3. A cyclophane as claimed in claim 3 wherein hydrocarbyl has 1 to 5 carbon atoms.
4. 4. A cyclophane as claimed in claim 1 wherein m is an integer of from 3 to 6.
5. 5. Cyanoacrylate adhesive compositions including as an accelerator a cyclophane of formula I :

   or of formula II :

   wherein R is (-R2-O)R3, in which R2 is substituted or unsubstituted alkyl with 2 to 6 carbon atoms a m is an integer of from 2 to 3000 and R3 is alkyl, aryl, alkaryl or substituted derivatives thereof; R1 is hydrogen, hydrocarbyl, aryl or hydrocarbylaryl; and n is 4, 6 or 8.
6. 6. An adhesive composition as claimed in claim 5 which comprises a compound of formula I or formula II in the range of from 0.1 to 5% by weight of the composition.
7. 7. An adhesive composition substantially as described herein with reference to Example 4.