MONOBLOC AEROSOL TUBE OR CAN HAVING A COATING COMPOSITION

Abstract

A monobloc aerosol tube or can being coated on at least a portion of an internal surface thereof with a coating composition, the coating composition comprising a thermoset powder composition, wherein the coating composition is substantially free of bisphenol A (BPA), bisphenol F (BPF), bisphenol A diglycidyl ether (BADGE) and bisphenol F diglycidyl ether (BFDGE); wherein the thermoset powder composition comprises an acid functional polyester material and a crosslinker material operable to crosslink the acid functionality on the acid functional polyester material.

Claims

1. A monobloc aerosol tube or can being coated on at least a portion of an internal surface thereof with a coating composition, the coating composition comprising a thermoset powder composition, wherein the coating composition is substantially free of bisphenol A (BPA), bisphenol F (BPF), bisphenol A diglycidyl ether (BADGE) and bisphenol F diglycidyl ether (BFDGE); wherein the thermoset powder composition comprises an acid functional polyester material and a crosslinker material operable to crosslink the acid functionality on the acid functional polyester material.

2. A monobloc aerosol tube or can according to claim 1, wherein the acid functional polyester material comprises the reaction product of a polyacid and a polyol.

3. A monobloc aerosol tube or can according to claim 2, wherein the polyacid comprises at least 50 mol % terephthalic acid and/or isophthalic acid based on the total number of moles of polyacid.

4. A monobloc aerosol tube or can according to any preceding claim, wherein the polyol comprises at least 10 mol % of neopentyl glycol based on the total number of moles of polyol.

5. A monobloc aerosol tube or can according to any preceding claim, wherein the acid functional polyester material has an acid number (AN) of at least 25 mg KOH/g.

6. A monobloc aerosol tube or can according to any preceding claim, wherein the acid functional polyester material has a gross OHV up to 5.0 mg KOH/g.

7. A monobloc aerosol tube or can according to any preceding claim, wherein the acid functional polyester material has a Tg from 60 C. to 70 C.

8. A monobloc aerosol tube or can according to any preceding claim, wherein the acid functional polyester material has a viscosity at 200 C. from 2 to 100 Poise.

9. A monobloc aerosol tube or can according to any of claims 2-9, wherein the crosslinker material comprises a hydroxyalkylamide material and/or a hydroxyalkylurea material and/or a carbodiimide resin.

10. A monobloc aerosol tube or can according to claim 9, wherein the crosslinker material contains a terminal chemical group as shown in Formula I: ##STR00023## wherein R.sup.1 represents an electron withdrawing group, such as (O); and Y.sup.1 and Y.sup.2 each, independently, represents a C.sub.1 to C.sub.3 alkylene group.

11. A monobloc aerosol tube or can according to either of claim 9 or 10, wherein the crosslinker material comprises a moiety according to Formula II: ##STR00024## wherein R.sup.1 and R.sup.2 each, independently, represent an electron withdrawing group, such as (O); Y.sup.1, Y.sup.2, Y.sup.3 and Y.sup.4 each, independently, represent a C.sub.1 to C.sub.3 alkylene group; and X is a C.sub.2 to C.sub.6 alkylene group.

12. A monobloc aerosol tube or can according to any one of claims 1 to 8, wherein the crosslinker material may contain a terminal chemical group as shown in Formula IV. ##STR00025## wherein Y.sup.5 and Y.sup.6 each, independently, represent hydrogen, an alkyl or a hydroxy functional alkyl having two or more carbon atoms and at least one of Y.sup.5 and Y.sup.6 is a hydroxyl functional alkyl having two or more carbon atoms.

13. A monobloc aerosol tube or can according to any preceding claim, wherein the acid functional polyester material of the present invention has a glass transition temperature (Tg) from 50 to 100 C. and a viscosity from 10 to 50 Poise.

14. A monobloc aerosol tube or can being coated on at least a portion of an internal surface thereof with a coating composition, the coating composition comprising a thermoset powder composition, wherein the coating composition is substantially free of bisphenol A (BPA), bisphenol F (BPF), bisphenol A diglycidyl ether (BADGE) and bisphenol F diglycidyl ether (BFDGE), wherein the thermoset powder composition comprises an acid functional polyester material and a crosslinker material operable to crosslink the acid functionality on the acid functional polyester material; and wherein the monobloc aerosol tube or can contains an alkali material.

15. A method of providing a monobloc aerosol tube or can having a coating composition on at least a portion thereof, the method comprising applying by ultra corona discharge a thermoset powder coating composition to a metal substrate, wherein the coating composition is substantially free of bisphenol A (BPA), bisphenol F (BPF), bisphenol A diglycidyl ether (BADGE) and bisphenol F diglycidyl ether (BFDGE); wherein the thermoset powder composition comprises an acid functional polyester material and a crosslinker material operable to crosslink the acid functionality on the acid functional polyester material.

Description

EXAMPLES

Acid Functional Polyester Example 1

[0166] A polyester was prepared from the following ingredients using the following method: A total of 2,000 g neopentyl glycol, 640 g ethyl glycol, 4,330 g terephthalic acid, 260 g isophthalic acid and 6 g monobutyltin oxide were added to a reaction vessel equipped with a stirrer, temperature probe glycol recovery setup (a packed column and a distillation head connected to a water cooled condenser) and a nitrogen sparge. The contents of the reaction vessel were heated to 235 C. with continuous removal of water distillate beginning at 170 C. The contents of the reaction vessel were held at 235 C. until 760 g of water had been distilled and the acid value of the reaction mixture was found to be 20 mg KOH/g. A sample from the reaction vessel was checked for net hydroxyl value and was found to be 26.6 mg KOH/g.

[0167] Then, the contents of the reaction vessel were cooled to 190 C. and 770 g trimellitic anhydride was added to the reaction mixture. The contents of the reactor were held at 190 C. until 25 g water had been distilled and the acid value of the reaction mixture was found to be 80 mg KOH/g. The contents of the reaction vessel were kept at 190 C. and vacuum was applied until the acid value of the reaction mixture was found to be 73 mg KOH/g. The viscosity of the reaction mixture at this stage was 345 poise at 165 C.

[0168] The contents of the reaction vessel were kept at 190 C. before being poured out, cooled to room temperature and broken into chips. The reaction product has a measured solid content of 100%, an acid value of 72 mg KOH/g, a melt viscosity of 403 poise at 165 C., a net hydroxyl value(minus) 68 mg KOH/g and a weight average molecular weight of 7,000 Da as measured against a polystyrene standard.

Acid Functional Polyester Example 2

[0169] An acid functional polyester was prepared from the following ingredients using the following method: A total of 5,892 g neopentyl glycol, 6,293 g terephthalic acid, 1,182 g isophthalic acid 3.1 g butylstannoic acid and 6.2 g of tris(nonylphenyl)phosphite were added to a reaction vessel equipped with a stirrer, temperature probe, a glycol recovery setup (a packed column and a distillation head connected to a water cooled condenser) and a nitrogen sparge. The contents of the reactor were heated to 235 C. with continuous removal of water distillate beginning at 140 C. The contents of the reactor were held at 235 C. until 1,620 g of water had been distilled and the acid number of the reaction mixture was found to be 14 mg KOH/g.

[0170] Then the contents of the reactor were cooled to 200 C. and 1,872 g isophthalic acid was added to the reaction mixture. The contents of the reactor were then heated to 235 C. and water was allowed to distill. The reactor was held at this temperature until 405 g of water had been distilled and the acid number of the reaction mixture was found to be 37 mg KOH/g.

[0171] Then the reaction mixture was cooled to 220 C. before 481 g of adipic acid was added to the reactor. The reactor was held at a temperature of 220 C. and water was allowed to distill. The contents of the reactor were held at this temperature until 118 g of water had been distilled and the acid number of the reaction mixture was found to be 46 mg KOH/g. After this, the contents of the reactor were held at 220 C. and a vacuum was applied to remove any remaining water. The vacuum was applied until the acid number of the reaction mixture was found to be 35 mg KOH/g. The reaction mixture was held at 190 C. before being discharged from the reactor.

[0172] The resulting polyester product has a measured solid content of 100%, an acid value of 35 mg KOH/g and a weight average molecular weight of 8,000 Da, as measured against a polystyrene standard.

Coating Compositions 1 and 2

[0173] Coating compositions 1, and 2 were prepared according to the formulations in Table 2. All amounts are given in parts by weight (pbw).

Comparative Coating Composition 1

[0174] Comparative coating composition 1 is a BPA-containing epoxy-based thermoset powder system available from TIGER Coatings GmbH & Co. KG and is a standard epoxy powder coating.

TABLE-US-00001 TABLE 2 Coating Composition Examples 1 and 2 Coating Coating composition 1 Composition 2 Polyester example 1 67.48 Polyester example 2 70.52 -hydroxyalkylamide 7.29 4.25 crosslinker.sup.1 Pigment.sup.2 9.45 9.86 Filler.sup.3 13.50 14.12 Additive 1.sup.4 1.08 Additive 2.sup.5 1.20 1.25 PAdditive 3.sup.6 0.3 0.3 Total 100.3 100.3 .sup.1PRIMID XL 552 available from Rohm and Haas .sup.2TiONA 595 a titanium dioxide pigment available from CRISTAL .sup.3Baramite Cimbar UF a barium sulphate filler available from CIMBAR Performance Minerals .sup.4Resiflow PL 200 a flow agent available from Estron Chemical .sup.5BYK-366P available from BYK-Chemie .sup.6Aerosil 200 available from Evonik

[0175] The properties of the coatings were tested via the following methods. Results are shown in Table 3.

Test Methods

Test Panel Preparation:

[0176] The coating samples were applied onto aluminium monobloc cans. Coating compositions 1 and 2 and comparative coating composition 1 were filled individually into an aluminium can and then drained for 10 minutes by standing the can upside down with an angle of 45; thereby coating the internal of the can. Subsequently, the can was placed in a convection oven to be cured for 4 minutes at 230 C.

[0177] The coated cans were tested for coating thickness, enamel rating after the impact test, also known as the falling weight test, cross hatch adhesion, cross cut adhesion, blush, discolouration, scratch resistance, crazing after folding and adhesion after folding after exposure to boiling water and after exposure to deodorant, styling mousse or shaving foam according to the procedures described below.

Coating Thickness:

[0178] Coating thickness was measured according to a non-destructive measurement of anodic coatings applied onto an aluminium base, using an ISOSCOPE MP30, coating thickness measuring instrument. The uncoated aluminium can was used for calibration after it had been flattened. The thickness of the coating of the coated cans was measured both on the side wall and on the bottom of the can. The measured thickness was reported in microns and represented either the average of 10 measurements or the lowest and highest values.

Impact Test:

[0179] The impact test was carried out according to ASTM D2794. The bottom part of the coated can was cut at a height of 20 mm and then with the coated side facing down on a Teflon coated fixture. A 1 kg weight is dropped from a 1 meter height to strike an indentation. The test was repeated two times under the same conditions on two individual cans. The integrity of the coating was measured using a WACO Enamel Rater Instrument and a 1% salt solution containing 0.1% dioctyl sodium sulfosuccinate and reported in milliamperes (mA).

MEK Rub Test:

[0180] The number of reciprocating rubs required to remove the coating was measured using a ball of cotton wool soaked in methyl ethyl ketone (MEK).

Boiling Water Tests:

[0181] The coated parts of the can were immersed in boiling demineralised water at 100 C. fro 15 minutes and subsequently removed and dried. They were then tested for cross cut adhesion, cutting edge adhesion, resistance to blush and discolouration.

[0182] Cross cut adhesion was measured according to the DIN ISO 2409 standard. Briefly, a crosshatch grid was made in the film using a grid comb and was then covered with tape (grade TESA 4104 clear). Within 60 seconds of its application, the tape was removed rapidly. The grid area is then checked for removal of the coating from the substrate. The adhesion was scored in accordance with the following scale: [0183] 0: The edges of the cuts are completely smooth; none of the squares of the grid are detached. [0184] 1: Small flakes of the coating are detached at intersections; less than 5% of the area is affected. [0185] 2: Some flakes of the coating are detached along the edges and/or at intersections of the incisions. The area affected is 5-15% of the grid. [0186] 3: The coating has peeled along the edges and on parts of the squares of the grid. The area affected is 15-35% of the grid. [0187] 4: The coating has peeled along the edges of the incisions in large strips and some squares are totally detached. The area affected is 35-65% of the grid. [0188] 5: All degrees of peeling and flecking that can be not classified under 4.

[0189] Cutting edge adhesion was measured by the following method. The coated parts of the can were cut along the length of the can from the lowest film thickness to the highest film thickness using scissors. The cutting edge adhesion was evaluated according to the level of peeling from the substrate and using a rating of 1-5, with 5 being the best.

[0190] Resistance to blush, which is white colouration of the film caused by water penetration and entrapment was measured by the following method. The coated parts of the can are sterilised in an autoclave for 1 hour at 130 C. in a 1% solution of arylsulphosuccinate detergent in water and then the film is observed visually. The appearance of the film is rated between 0 and 5. Grade 0 corresponds to perfect film appearance with no discernible attack. Grade 5 corresponds to complete attack of the film across the whole of the score line.

[0191] Discolouration was measured by the following method. The coating is applied on can parts which are pre-coated with white enamel and sterilized in water with 1% teepol (sodium dodecyl benzene sulphonate detergent) for 1 hour at 130 C. and then the film is observed visually. The appearance is rated between 0 and 5. Grade 0 corresponds to no yellowing and grade 5 to a high yellowing level.

Pack Performance Tests:

[0192] Coated cans were packed with one of deodorant, styling mousse or shaving foam and left at 55 C. for two weeks. After this time, the cans were then tested for cross cut adhesion, cutting edge adhesion, blush, discolouration, scratch resistance, crazing after folding and adhesion after folding according to the same methods as described above in relation to the boiling water tests.

TABLE-US-00002 TABLE 2 Test Results Coating Comparative Com- Coating Coating position 1 Composition 2 Composition 1 Flexibility Thickness/m - A 37-41 29-31 28-30 Thickness/m - B 12-16 37-43 19-23 Enamel rater/mA - A 4.8 0.4 0 Enamel rater/mA - B 0.3 0 0.5 MEK Resistance Thickness/m - A 16-27 16-25 14-25 Thickness/m - B 15-27 18-24 15-29 MEK double rubs - A 100 48 100 MEK double rubs - B 100 40 100 Boiling Tests (15 mins @ 100 C. in demineralised water) Thickness/m - A 16-26 17-32 16-37 Thickness/m - B 15-27 16-24 14-25 Cross hatch adhesion - A 0 0 0.5 Cross hatch adhesion - B 0 0 0 Cutting edge adhesion - A 5 5 5 Cutting edge adhesion - B 5 5 4.5 Blush - A 5 5 5 Blush - B 5 5 5 Discolouration - A 4 4 4* Discolouration - B 4 4 4* Pack Performance after 2 weeks at 55 C. Deodorant Thickness/m - A 18-21 9-21 23-25 Thickness/m - B 21-23 10-28 20-25 Cross hatch adhesion - A 5 5 5 Cross hatch adhesion - B 5 5 5 Cutting edge adhesion - A 5 5 5 Cutting edge adhesion - B 5 5 5 Blush - A 3.5* 5 2 Blush - B 3* 5 2 Discolouration - A 5 5 5 Discolouration - B 5 5 5 Styling Mousse Thickness/m - A 19-22 7-20 21-30 Thickness/m - B 20-22 12-26 17-25 Cross hatch adhesion - A 5 5 5 Cross hatch adhesion - B 5 5 5 Cutting edge adhesion - A 5 4 5 Cutting edge adhesion - B 5 4 5 Blush - A 4.5 5 4.5 Blush - B 4.5* 5 5 Discolouration - A 5 5 5 Discolouration - B 5 4.5 5 Shaving Foam Thickness/m - A 19-26 5-16 12-34 Thickness/m - B 22-23 9-30 17-26 Cross hatch adhesion - A 4.5 complete 5 Cross hatch adhesion - B 5 delamination 5 Cutting edge adhesion - A 4.5 5 Cutting edge adhesion - B 4.5 5 Blush - A 4 4 Blush - B 4 4 Discolouration - A 4 5 Discolouration - B 4.5 5

[0193] The results show that the coating compositions according to the present invention perform as well, or better, than the liquid coatings of the comparative examples.

[0194] Attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

[0195] All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

[0196] Each feature disclosed in this specification (including any accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

[0197] The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.