GB2447933A - Cyanoacrylate monomer for forming an adhesive polymer - Google Patents

Abstract

A cyanoacrylate monomer, containing a side chain of at least three carbon atoms, such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl or cyclodecyl, cyclopropyl methyl, 1-cyclopropyl ethyl, cyclobutyl methyl, cyclopentyl methyl, 1-cyclopentyl ethyl, 3-pentyl-1-propyl, cyclohexyl methyl, 1-cyclohexyl ethyl, 2-cyclohexyl ethyl, 3-cyclohexyl-1-propyl, 3-cyclohexyl-1-propyl or 4-cyclohexyl-1-butyl. The monomer is preferably cyclohexyl cyanoacrylate monomer. The monomer is used for forming an adhesive polymer suitable for use in an environment containing water or water vapour.

Description

Cyanoacrylate Monomer The present invention relates to a cyanoacrylate

monomer and to polymers formed therefrom It is well known that that the polymeric adhesives formed from conventional cyanoacrylate monomers e.g. methyl and ethyl cyanoacrylate monomers are not generally suitable for use in a water-containing wet, damp or moist environment. Such environments are known to adversely affect the adhesive and the adhesive bond.

Thus cyanoacrylate polymeric compounds so formed are not used for reliable, durable or permanent repairs in an environment which is likely to contain for example water vapour at some stage such as the outdoors, marine environments, medical and cosmetic applications where a permanent or durable fixture is needed.

**** These compounds are unsuitable for use in the environments described because in * * damp, wet or moist conditions in particular the cyanoacrylate polymer which forms during curing of the adhesive monomer is attacked chemically by the water and S ultimately degrades causing the bond so formed to fail. The bond can degrade by as * much as 55% in a water-borne environment over a period of 80 days at 40C, although *: ::: the exact figure is somewhat dependent on the nature of the substrate. ** S * S S

* However we have surprisingly found that certain selected cyanoacrylate polymers formed from suitable monomers are resistant to attack by the water containing environments defined above.

Therefore in accordance with the present invention, we provide a cyanoacrylate monomer for forming an adhesive polymer suitable for use in an environment containing water or water vapour in which the cyanoacrylate monomer has a side chain of at least three carbon atoms.

Preferably the side chain is selected from a cycloalkyl group such as, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl and cyclodecyl.

Suitably the side chain is selected from a cycloalkyl alkyl group, cyclopropyl methyl, I -cyclopropyl ethyl, cyclobutyl methyl, cyclopentyl methyl, I -cyclopentyl ethyl, 3- pentyl-l-propyl, cyclohexyl methyl, 1-cyclohexyl ethyl, 2-cyclohexyl ethyl, 3-cyclohexyl-I -propyl and 4-cyclohexyl-I -butyl.

Conveniently the side chain is selected from unsaturated cycloalkyl groups such as cyclohexen-1-methyl, 2-cyclohexen-1-methyl.

The side chain may be selected from cycloalkoxy alkyl groups such as 2-(cyclohexyloxy) ethyl.

Preferably the side chain is selected from aromatic groups such as phenyl methyl and phenyl. S... * S

We have found that a polymer formed from a cyclohexyl cyanoacrylate monomer is a * particularly suitable adhesive for use in a water-containing atmosphere. ***

:::: An embodiment of the invention will now be particularly described with reference to *. the following example:-Shear strength tests were made on cleaned steel test pieces bonded with either ethyl cyanoacrylate or cyclohexyl cyanoacrylate. Samples were conditioned at 40 C either in a dry or wet (immersed in tap water) environment for periods up to 80 days. The samples bonded with ethyl cyanoacrylate maintained some 75% of their strength in dry conditions whereas in wet conditions the samples only retained some 45% of their strength. Samples bonded with cyclohexyl cyanoacrylate performed much better. In dry conditions where 83% of strength was retained and in wet conditions some 87% of strength was retained.

--

Claims (10)

1. Claims I. A cyanoacrylate monomer for forming an adhesive polymer

   suitable for use in an environment containing water or water vapour, the cyanoacrylate monomer containing a side chain of at least three carbon atoms.
2. 2. A monomer as claimed in claim I in which the side chain is selected from a cycloalkyl group such as cyclopropyl, cyclobutyl, cyclopenlyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl and cyclodecyl.
3. 3. A monomer as claimed in claim I or claim 2 in which the side chain is selected from a cycloalkyl alkyl group, cyclopropyl methyl, I -cyclopropyl ethyl, cyclobutyl methyl, cyclopentyl methyl, 1-cyclopentyl ethyl, 3-pentyl-l-propyl, cyclohexyl methyl, 1 -cyclohexyl ethyl, 2-cyclohexyl ethyl, 3-cyclohexyl-I -propyl and 4-cyclohexyl-1 -butyl. * S S...
4. 4. A monomer as claimed in any of claims 1 to 3 in which the side chain is selected from unsaturated cycloalkyl groups such as cyclohexen-1-methyl and 2-cyclohexen-l-S..

   * methyl. * * . S
5. 5. A monomer as claimed in any of claims Ito 4 in which the side chain is selected from cycloalkoxy alkyl groups such as 2-(cyclohexyloxyl) ethyl.
6. 6. A monomer as claimed in any of claims I to 5 in which the side chain is selected from aromatic groups such as phenyl methyl and phenyl.
7. 7. A monomer as claimed in any of the preceding claims in which the monomer is a cyclohexyl cyanoacrylate monomer.
8. 8. A monomer as claimed in any of claims I to 7 in which the environment is wet, damp or moist.
9. 9. A monomer substantially as hereinbefore described with reference to the example.
10. 10. A polymer when formed from a monomer as claimed in any of the preceding claims. * * * S.. * * S S... * S. * S

    S I..

    S 5*55 * SS S. * S. *

    S S *5