Nail Glue Composition

Abstract

A nail glue composition includes at least one cyanoacrylate of the formula CH.sub.2═C(CN)COOR, an anionic stabiliser, and an antioxidant stabiliser comprising at least one stabiliser compound selected from the group consisting of α-tocopherol, β-tocopherol, γ-tocopherol, δ-tocopherol, α-tocotrienol, β-tocotrienol, γ-tocotrienol, δ-tocotrienol, and derivatives thereof. R is ethyl, methoxyethyl, ethoxyethyl, n-butyl or octyl or mixtures thereof. The at least one stabiliser compound is in an amount of at least 0.02 wt % of the nail glue composition.

Claims

1. A nail glue composition comprising: at least one cyanoacrylate of the formula:
CH.sub.2═C(CN)COOR wherein R is ethyl, methoxyethyl, ethoxyethyl, n-butyl or octyl or mixtures thereof; an anionic stabiliser; and an antioxidant stabiliser comprising at least one stabiliser compound selected from the group consisting of: α-tocopherol, β-tocopherol, γ-tocopherol, δ-tocopherol, α-tocotrienol, β-tocotrienol, γ-tocotrienol and δ-tocotrienol; and derivatives thereof; in which the at least one stabiliser compound is in an amount of at least 0.02 wt % of the nail glue composition.

2. The nail glue composition according to claim 1, wherein the at least one stabiliser compound is present in an amount of at least 0.1 wt % of the nail glue composition.

3. The nail glue composition according to claim 2, wherein the at least one stabiliser compound is present in an amount of at least 0.2 wt % of the nail glue composition.

4. The nail glue composition according to claim 1, wherein the at least one cyanoacrylate is in a range of 85 to 99 wt % of the nail glue composition.

5. The nail glue composition according to claim 1, wherein the at least one stabiliser compound is selected from the group consisting of: α-tocopherol, β-tocopherol, γ-tocopherol, δ-tocopherol, α-tocotrienol, β-tocotrienol, γ-tocotrienol and δ-tocotrienol.

6. The nail glue composition according to claim 1, wherein the antioxidant stabiliser comprises at least 0.02 wt % α-tocopherol.

7. The nail glue composition according to claim 1, further comprising a thickener.

8. The nail glue composition according to claim 7, wherein the thickener is polymethyl methacrylate.

9. The nail glue composition according to claim 8, wherein the polymethyl methacrylate is present in a range of 0.1 wt % to 14 wt % of the nail glue composition.

10. The nail composition according to claim 1, wherein the antioxidant stabiliser is present in a range 0.03% to 0.7% of the nail glue composition.

11. The nail composition according to claim 1, further comprising a plasticiser.

12. The nail glue composition according to claim 11, wherein the plasticiser is selected from Triacetin and Tributyl Citrate.

13. The nail glue composition according to claim 11, wherein the plasticiser is present in a range 2 wt % to 15 wt %.

14. The nail glue composition according to claim 1, further comprising a colourant.

15. The nail glue composition according to claim 14, wherein the colourant is D&C Red 7.

16. The nail glue composition according to claim 14, wherein the colourant is present in a range 0.001 wt % to 0.005 wt %

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0042] FIG. 1 is a chemical structure drawing of various Vitamin E compounds.

DETAILED DESCRIPTION

[0043] The following specific formulation is one example of how the present invention may be carried out:

TABLE-US-00001 TABLE 1 Formulation 1 CAS# Percent w/w Ethyl cyanoacrylate 7085-85-0 95.3 Polymethyl methacrylate (PMMA) 9011-14-7 4.5 α-tocopherol 59-02-9 0.2 TOTAL 100

[0044] Testing by the inventor has shown that the formulation in Table 1 is unexpectedly superior to nail glues containing traditional phenolic stabilisers in increasing both the longevity and durability of the adhesion of the artificial nail to the natural nail, and in improving the lap shear tensile strength of the nail glue measured by the tensile strength required to break the adhesive bond when applied between two strips of mild steel and similarly between two strips of acrylonitrile butadiene styrene (ABS) plastic.

Test Results—Stability

[0045] Various amounts of α-tocopherol and BHA were added separately to ethyl 2-cyanaocrylate monomer with no thickener added and only anionic stabiliser. Samples were then placed in a temperature-controlled oven at 82° C. for three days and removed and allowed to cool to 20° C. The initial viscosity at 20° C. measured in cPs, was then compared with the viscosity after storage for three days at an elevated temperature. The results of the above experiment show that α-tocopherol has a similar or greater stabilising effect on ethyl-2-cyanaocrylate monomer when compared to BHA at similar addition levels. Therefore, α-tocopherol can be used as a direct replacement for BHA in cyanoacrylate adhesives.

Test Results—Longevity

[0046] Twenty (adult) participants participated in a longevity test whereby a thin layer of Formulation 1 adhesive was applied to the natural nails of the dominant hand and an artificial nail made from acrylonitrile butadiene styrene (ABS) plastic was adhered to each natural nail by pressing down firmly for five seconds. The participants then recorded the number of days before the first artificial nail and the second artificial nail lost complete adhesion to the natural nail and fell or ‘popped’ off.

[0047] In addition, a traditional nail adhesive formulation containing Ethyl cyanoacrylate, Polymethyl methacrylate and the phenolic inhibitor Butylated Hydroxy Anisole (BHA) was used to apply artificial nails to the natural nail of the less dominant hand by the method described above. Similarly, the participants then recorded the number of days before the first artificial nail and the second artificial nail lost complete adhesion to the natural nail and fell or ‘popped’ off.

[0048] The formulation of the traditional nail adhesive is as provided in Table 2 below:

TABLE-US-00002 TABLE 2 Formulation 2 CAS# Percent w/w Ethyl cyanoacrylate 7085-85-0 95.3 Polymethyl methacrylate (PMMA) 9011-14-7 4.5 Butylated Hydroxy Anisole (BHA) 25013-16-5 0.2 TOTAL 100

[0049] The results of the test are provided in Table 3 below.

TABLE-US-00003 TABLE 3 Pop Off First Nail (Days) Participant Formulation 1 Formulation 2 1 8 6 2 10 6 3 1 1 4 7 4 5 10 7 6 8 6 7 6 6 8 4 3 9 3 3 10 7 8 11 5 2 12 6 7 13 9 8 14 8 9 15 8 5 16 10 7 17 5 2 18 5 3 19 8 4 20 9 7 Total 137 104 Mean 6.85 5.20 Median 7.5 6 Increase - Mean 32% — Increase - Median 25% —

[0050] The increase in the mean and the median days for the longevity of the artificial nail adhered to the natural nail between Formulation 1 and Formulation 2 is 32% and 25% respectively.

TABLE-US-00004 TABLE 4 Pop Off Second Nail (Days) Participant Formulation 1 Formulation 2 1 9 7 2 12 8 3 3 2 4 8 11 5 12 11 6 10 7 7 9 7 8 6 5 9 4 4 10 8 8 11 5 3 12 7 8 13 12 9 14 9 9 15 10 7 16 11 9 17 8 4 18 6 4 19 11 7 20 10 8 Total 170 138 Mean 8.5 6.9 Median 9 7 Increase - Mean 23% — Increase - Median 29% —

[0051] The increase in the mean and the median days for the longevity of the artificial nail adhered to the natural nail between Formulation 1 and Formulation 2 is 23% and 29% respectively.

[0052] Formulation 1 was applied to the dominant hand and the nails would generally be exposed to more wear than the less dominant hand. This confirms that the substitution of BHA inhibitor by α-tocopherol in the nail adhesive formulation improves the adhesion of the artificial nail to the natural nail by a statistically significant amount.

Test Results—Tensile

[0053] It is not possible to devise an experiment by which the lap shear tensile strength of an artificial nail bonded to the natural nail by use of a nail adhesive can easily be measured. An acceptable substitute test is to measure the lap shear strength of Formulation 1 compared to Formulation 2 by the following method: [0054] 1) Lightly abrade the ends of a mild steel strip measuring 100 mm×25 mm×1.5 mm to smooth off the uneven edges. [0055] 2) Thoroughly clean the ends of the mild steel strips with acetone to remove any grease or dirt. [0056] 3) Apply a small amount of the adhesive to the cleaned end of the steel strip. Position the second steel strip on top the first steel strip to create a 12.5 mm overlap. [0057] 4) Hold the steel strips together using bulldog clips and leave to cure at 20° C. for 24 hours then clamp the test piece in the jaws of the tensile tester and set the machine in motion (1 mm/min). [0058] 5) Record the results when the test piece breaks. Repeat a further two times.

[0059] The above lap shear tensile strength test was repeated exactly as described above but with two strips of acrylonitrile butadiene styrene (ABS), a common thermoplastic polymer.

TABLE-US-00005 TABLE 5 Lap Shear Strength N/mm.sup.2 Mild Steel Formulation 1 Formulation 2 15.9 12.3 16.4 11.6 16.1 12.2 Mean 16.1 Mean 12.0

[0060] The mean lap shear tensile strength measured for Formulation 1 was 16.1 N/mm.sup.2 and for Formulation 2, the mean lap shear strength was measured at 12.0 N/mm.sup.2. There is a 34% increase in lap shear tensile strength for Formulation 1 compared to Formulation 2. This confirms that the substitution of BHA inhibitor by α-tocopherol in the nail adhesive formulation improves the lap shear strength by a statistically significant amount when tested on mild steel strips.

TABLE-US-00006 TABLE 6 Lap Shear Strength N/mm.sup.2 ABS Formulation 1 Formulation 2 4.1 3.1 3.8 2.6 3.6 2.9 Mean 3.8 Mean 2.9

[0061] The mean lap shear tensile strength measured for Formulation 1 was 3.8 N/mm.sup.2 and for Formulation 2, the mean lap shear strength was measured at 2.9 N/mm.sup.2. There is a 31% increase in lap shear tensile strength for Formulation 1 compared to Formulation 2. This confirms that the substitution of BHA inhibitor by α-tocopherol in the nail adhesive formulation improves the lap shear strength by a statistically significant amount when tested on ABS strips.

[0062] It should be understood that the embodiments described herein are merely exemplary and that a person skilled in the art may make many variations and modifications without departing from the scope of the invention as defined by the claims.

Variations

[0063] The above embodiments utilise the α-tocopherol Vitamin E compound. Other Vitamin E compounds are also possible, specifically β-tocopherol, γ-tocopherol, δ-tocopherol, α-tocotrienol, β-tocotrienol, γ-tocotrienol and δ-tocotrienol.

[0064] In an embodiment, the antioxidant inhibitor is β-tocopherol, which is present in an amount from 0.02 wt % to 0.5 wt % of the composition.

[0065] In an embodiment, the antioxidant inhibitor is γ-tocopherol, which is present in an amount from about 0.02 wt % to 0.5 wt % of the composition.

[0066] In an embodiment, the antioxidant inhibitor is δ-tocopherol, which is present in an amount from about 0.02 wt % to 0.5 wt % of the composition.

[0067] In an embodiment, the antioxidant inhibitor is α-tocotrienol, which is present in an amount from about 0.02 wt % to 0.5 wt % of the composition.

[0068] In an embodiment, the antioxidant inhibitor is β-tocotrienol, which is present in an amount from about 0.02 wt % to 0.5 wt % of the composition.

[0069] In an embodiment, the antioxidant inhibitor is γ-tocotrienol, which is present in an amount from about 0.02 wt % to 0.5 wt % of the composition.

[0070] In an embodiment, the antioxidant inhibitor is δ-tocotrienol, which is present in an amount from about 0.02 wt % to 0.5 wt % of the composition.

[0071] In an embodiment, the thickener is PMMA.

[0072] In an embodiment, the thickener is PMMA in combination with fumed silica.

[0073] In addition to the embodiments above, a plasticiser may be added.

[0074] In an embodiment, the plasticiser is Triacetin which is present in an amount from 2 wt % to 15 wt %.

[0075] In an embodiment, the plasticiser is Tributyl Citrate which is present in an amount from 2 wt % to 15 wt %.

[0076] In addition to the embodiments above, a colourant may be added.

[0077] In an embodiment, the colourant is D&C Red 7 which is present in an amount from 0.001 wt % to 0.005 wt %.