Caustic-resistant polymer coatings for glass
OwnerGeorge Wyatt Prejeaninventor
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Abstract
Improved caustic-resistant coatings for glass which comprise (1) a primer layer consisting essentially of an epoxy resin containing a curing agent, e.g., polyamide, amine, etc., and an organofunctional silane either in a single layer or separate layers, in order on the glass, (a) organofunctional silane and (b) epoxy resin, and (2) a copolymer of alpha-olefins of the formula R--CH.dbd.CH.sub.2, where R is a radical of hydrogen or alkyl radicals having from 1 to 8 carbon atoms, and alpha, beta-ethylenically unsaturated carboxylic acids having from 3 to 8 carbon atoms, said copolymer having from 0 to 100 percent of the carboxylic acid groups ionized by neutralization with metal ions.
Claims20
Returnable glass bottles for carbonated beverages, said bottles being coated on the outer surfaces with a clear, cross-linked resin providing abrasion resistance and protection from flying glass in care of fracture, said coating being caustic-resistant, exhibiting strong adherence to glass even after repeated treatments with 5% aqueous NaOH at 80.degree. C, said clear, abrasion- and causticresistant coating being at least 8 mils thick and comprising:
- 1. a cured primer layer on the glass, and
- 2. an outer layer of a copolymer of ethylene,
- said primer layer (1) consisting essentially of
- A from 0.5 to 5% by weight of an organofunctional silane of the formula (RO--.sub.3 Si (CH.sub.2 --.sub.x R.sup.1, where
- Ro-- is a hydrolyzable alkoxy group in which R is an alkyl radical of 1 to 4 carbon atoms,
- R.sup.1 is a functional group selected from --NH.sub.2, ##STR8## and x is an integer from 1 to 4, inclusive,
- B. an epoxy resin,
- C. a curing agent selected from the group consisting of amines and reactive polyamides containing excess amine groups,
- and optionally at least one member of the group consisting of
- D. a water-soluble metal salt, and
- E. diethylene glycol monoethyl ether,
- and the copolymer of said outer layer (2) consisting essentially of a random copolymer of ethylene in which the alpha, beta-unsaturated carboxylic acid is selected from the group consisting of acrylic acid and methacrylic acid having from 10% to 100% of the carboxyl groups ionized by metal ions having an ionized valence from one to three, inclusive, and in which the ethylene content of the copolymer is at least 70 mol %, based on the copolymer, the alpha, beta-unsaturated carboxylic acid content of said copolymer is from 0.2 to 5 mol %, inclusive, based on said copolymer, and any third monomer component optionally copolymerized in said copolymer is a monoethylenically unsaturated monomer.
Glass coated with a strongly adhering, clear caustic-resistant coating which comprises
- 1. a cured primer layer consisting essentially of a combination of
- A. an organofunctional silane,
- B. an epoxy resin and
- C. a curing agent taken from the group consisting of amines and reactive polyamides containing excess amine groups
- where (A) and (B) and (C) are in a single layer or in two layers, (A) in a layer adjacent to the glass and (B) + (C) in a layer over (A), and
- 2. a copolymeric layer consisting essentially of a copolymer of an alpha-olefin of the formula R--CH.dbd.CH.sub.2, where R is a radical selected from the class consisting of hydrogen and alkyl radicals having from 1 to 8 carbon atoms, and alpha, betaethylenically unsaturated carboxylic acids having from 3 to 8 carbon atoms, said copolymers having from 0 to 100 percent of the carboxylic acid groups ionized by neutralization with metal ions, said metal ions having an ionized valence of from one to three inclusive when the unsaturated acid is a monocarboxylic acid and an ionized valence of one when the unsaturated acid is a dicarboxylic acid and said metal ions being selected from the group consisting of uncomplexed and complexed metal ions, said copolymer being a direct copolymer of the alpha-olefin and the unsaturated carboxylic acid in which the carboxylic acid groups are randomly distributed over all molecules and in which
- a. the alpha-olefin content of the copolymer is at least 70 mol percent, based on the copolymer,
- b. the unsaturated carboxylic acid content of the copolymer is from 0.2 to 5 mol percent, based on the copolymer, and
- c. any other monomer component optionally copolymerized in said copolymer is monoethylenically unsaturated.
Dependencies are inferred from the claim text.