Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – At least one aryl ring which is part of a fused or bridged...
Reexamination Certificate
1999-09-03
2001-01-30
Niland, Patrick D. (Department: 1714)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
At least one aryl ring which is part of a fused or bridged...
C428S035200, C524S612000
Reexamination Certificate
active
06180715
ABSTRACT:
BACKGROUND OF THE INVENTION
In paper packaging applications, it is desirable to provide barriers against water, oxygen, and carbon dioxide. Wettability of a paper surface can be reduced using sizing agents, while gas barriers can be formed by coating the paper with a continuous film of a suitable material. Examples of such barrier-producing films are paraffin wax, polyethylene, ethylene-vinyl acetate copolymer, and poly(vinylidene chloride) (PVDC). Of these, PVDC has the best water-, vapor-, and oxygen-barrier properties. Moreover, unlike other high oxygen-barrier materials, PVDC is almost insensitive to water. However, because of its high chlorine content, PVDC tends to corrode processing equipment, which increases manufacturing costs.
It would be an advantage in the art to prepare a non-chlorine-containing, self-dispersing latex or solution that can be used to make a coating that is effective as a barrier against small molecules. It would be further advantageous if the barrier properties were not adversely affected by contact with water. It would be desirable if the coating adhered to a substrate without the aid of an ancillary adhesive. Finally, it would be desirable for some applications that this coating be biodegradable, so that the product can be composted subsequent to its intended use.
SUMMARY OF THE INVENTION
The present invention is a stable aqueous dispersion or solution of an acid salt of a polyetheramine having structural units represented by the formula:
where R
1
is independently in each occurrence hydrogen or C
1
-C
12
alkyl; Y is predominantly a hydrocarbylene moiety; and X is
wherein R
2
is independently in each occurrence C
2
-C
20
hydrocarbylene; Z is independently in each occurrence H, alkylamido, hydroxyl, alkoxy, alkylcarbonyl, aryloxy, arylcarbonyl, halo, or cyano.
In another aspect, the present invention is a method of preparing a stable aqueous dispersion or a solution of an acid salt of a polyetheramine comprising the step of contacting the polyetheramine with water and an acid under such conditions to form the stable aqueous dispersion or solution, where the polyetheramine has structural units represented by the following formula:
where R
1
is independently in each occurrence hydrogen or C
1
-C
12
alkyl; where X is
wherein R
2
is independently in each occurrence C
2
-C
20
hydrocarbylene; Z is independently in each occurrence H, aLkylamido, hydroxyl, alkoxy, alkylcarbonyl, aryloxy, arylcarbonyl, halo, or cyano; and Y is predominantly a hydrocarbylene moiety.
The solution or stable dispersion of the acid salt of the polyetheramine can be easily applied to a wide variety of surfaces to impart a thinner and more uniform barrier than what is generally available from an extruded film. The coatings formed from the solution or dispersion tend to have enhanced physical properties due to the absence of an ancillary surfactant, which could interfere with the integrity of the coating.
DETAILED DESCRIPTION OF THE INVENTION
The acid salt of the polyetheramine can be prepared by contacting the polyetheramine represented by Formula I with an acid under such conditions to at least partially neutralize the polyetheramine. Referring now to Formula I, X is preferably
R
1
is preferably H or methyl; R
2
is preferably C
2
-C
6
branched or linear alkyl, more preferably ethylene; and Z is preferably hydroxyl Y is preferably a divalent aromatic unit such as:
The polyetheramine represented by Formula I can be prepared by contacting one or more of the diglycidyl ethers of a dihydric phenol with an amine having two amine hydrogens under conditions sufficient to cause the amine moieties to react with epoxy moieties to form a polymer backbone having amine linkages, ether linkages and pendant hydroxyl moieties. Examples of diglycidyl ethers of dihydric phenols include the diglycidyl ethers of bishydroxyphenyl propanes, of 4,4′-dihydroxybiphenyl, of resorcinol, of catechol, and of hydroquinone, and combinations thereof. Preferred diglycidyl ethers of dihydric phenols are the diglycidyl ethers of resorcinol and of bisphenol A, and combinations thereof. The amine is preferably a monoalkanolamine, more preferably monoethanolamine. Many of these polyetheramines are described in U.S. Pat. No. 5,275,853. They can also be prepared by contacting a diglycidyl ether or an epihalohydrin with a difunctional amine.
Partial neutralization is preferred. Preferably, not less than about 20 percent, more preferably not less than about 30 percent, and most preferably not less than about 40 percent of the nitrogen atoms in the polyetheramine are protonated; preferably not more than about 80 percent, more preferably not more than about 70 percent, and most preferably not more than about 60 percent of the nitrogen atoms in the polyetheramine are protonated. Preferably, the polyetheramine is contacted with water and acid at a temperature not less than about 70° C., more preferably not less than about 90° C., and most preferably not less than about 110° C., and preferably not greater than about 200° C., and more preferably not greater than about 150° C. A high-pressure reactor such as a PARR reactor can be conveniently used to carry out the reaction, particularly under most preferred conditions.
The acid can be protic or aprotic, but is preferably protic. Examples of suitable protic acids include hydrochloric acid, hydrobromic acid, hydroiodic acid, hydrofluoric acid, sufuic acid, phosphoric acid, nitric acid, lactic acid, acetic acid, formic acid, propanoic acid, toluene sulfonic acid, carbonic acid, carbon dioxide, and citric acid.
It has been surprisingly discovered that a self-dispering stable aqueous dispersion, not merely an aqueous suspension, of the polyetheramine can be prepared under the conditions described herein. Consequently, a water based dispersion that is free of, or substantially free of any organic solvent or ancillary surfactant, can be applied to the surface of a substrate to form a barrier coating.
The aqueous dispersion or solution of the polyetheramine salt is useful as a coating for substrates such as wood, metal, ceramic, glass, other polymers, paper, paper board cloth, woven fibers, non-woven fiber mats, synthetic fibers, and carbon fibers. The aqueous dispersion or solution is also useful as a film, a foam, an adhesive, a laminate, a molded article, an extruded article, a flexible or rigid container, or a packaging material
The following examples are for illustrative purposes only and are not intended to limit the scope of this invention.
REFERENCES:
patent: 5275853 (1994-01-01), Silvis et al.
patent: 5834078 (1998-11-01), Cavitt et al.
patent: 5962093 (1999-10-01), White et al.
Niland Patrick D.
The Dow Chemical Company
Willis Reid S.
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