RHEOLOGY MODIFIER AND COMPATIBILIZER

Abstract

The invention pertains to the use of lactam as a rheology modifier and/or compatibilizer.

Claims

1. (canceled)

2. (canceled)

3. A coating composition comprising: a lactam; and optionally water; and a first resin, wherein the composition has a lower viscosity compared to a composition without the lactam, and/or the composition is more compatible compared to a composition without the lactam.

4. A composition comprising: a lactam; and optionally water; and a monomer, oligomer and/or polymer, wherein the composition has a lower viscosity compared to a composition without the lactam, and/or the composition is more compatible compared to a composition without the lactam.

5. An emulsion comprising: water; oil; and a lactam, wherein the composition has a lower viscosity compared to a composition without the lactam, and/or the composition is more compatible compared to a composition without the lactam.

6. A dispersion comprising: a lactam; and optionally water; and solid particles, wherein the composition has a lower viscosity compared to a composition without the lactam, and/or the composition is more compatible compared to a composition without the lactam.

7. A coated substrate comprising: a substrate; and a cured coating composition applied to at least part of the substrate, the coating composition being in accordance with claim 3.

8. The coated substrate according to claim 7, wherein the substrate is a metal.

9. The coated Coated substrate according to claim 7, wherein the coated substrate is a food or beverage container.

10. A process for preparing a coated substrate comprising the steps of: (a) applying the coating composition according to claim 3 to a substrate; and (b) curing the coating composition.

11. The process of claim 10 further comprising the step of shaping the coated substrate to a food or beverage container.

Description

EXAMPLES

Example 1 and Comparative Example A: Coating Compositions

[0132] A typical water-based over varnish (Comparative Example A), commercialized by the Applicant under the brand name NovoShield 4718E, 40% solids (ASTM D2369), has been applied on a 33 cl aluminium beer and beverage cans, provided with black, red and green ink supplied by Sun Chemical. After thermal curing in a box oven at 200° C. for four minutes, film weights have been checked (approx. 100 mg dry). All treated cans passed pasteurization (30 minutes at 82° C.) and no adhesion loss was observed. This is the reference coated substrate.

[0133] A new coating composition (Example 1) contains 17 wt % Demineralized water, 12 wt % Caprolactam (100% solids, ASTM D2369), 40 wt % Neutralized water-thinnable polyester (70% solids), 25 wt % Aminoplast (HMMM, 100 solids), 3 wt % Adhesion promoter (70% solids), 2 wt % Wax emulsion (30% solids) and 1 wt % Additives (50% solids).

[0134] The composition contains 68.2% solids, ASTM D2369, which is 70% higher than a typical standard water-based over varnish. Their viscosities, however, are the same (approx. 55 seconds, Ford 4 cup at 25 C), demonstrating the excellent compatibilizer and resin solubility strength of caprolactam. The composition according to this invention has been applied on a 33 cl aluminium beer and beverage cans, provided with black, red and green ink supplied by Sun Chemical. After thermal curing in a box oven at 200° C. for four minutes, film weights have been checked (approx. 100 mg dry). All treated cans passed pasteurization (30 minutes at 82° C.) and no adhesion loss was observed. Moreover, the treated cans exhibit a high gloss level.

Example 2 and Comparative Example B: CMC in Water

[0135] 5 g of γ-butyrolactam (5 wt %) was mixed with 3 g of sodium carboxymethyl cellulose (CMC with Mw of about 100,000; 3 wt %) in water. The resulting liquid is very thin and transparent

[0136] As comparative example, 3 g of sodium carboxymethyl cellulose (CMC with Mw of about 100,000; 3 wt %) was dissolved in water.

[0137] The dissolution rate of CMC is considerably faster in the liquid of Example 2 (within minutes) than in the Comparative Example B (about 30 minutes). Moreover, the viscosity of the liquid of Example 2 is substantially lower than the viscosity of the liquid of the Comparative Example B.

Example 3: Fumed Silica

[0138] 8.5 g of γ-butyrolactam (liquid) was mixed with 1.5 g of fumed silica (15 wt %). The mixture was heated to about 70° C. until the mixture turns into a liquid. Subsequently, the liquid mixture was cooled to room temperature. A pourable, liquid dispersion was obtained.

[0139] At 50 wt % fumed silica, a solid is obtained which has improved flow properties (i.e. is free flowing) and is considerably compacter (less voluminous) than fumed silica per se.