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
1995-06-05
2001-04-24
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...
C524S590000, C524S839000, C524S840000, C564S286000, C564S294000, C564S281000
Reexamination Certificate
active
06221954
ABSTRACT:
BACKGROUND AND DESCRIPTION OF THE INVENTION
This invention relates to processes for the manufacture of cationic polyurethane compositions and quaternary ammonium salts and to the new compositions prepared thereby. In particular this invention relates to the use of alkylene oxides to prepare cationic polyurethane compositions and quaternary ammonium salt intermediates. An important aspect of the present invention is the use of alkylene oxides such as ethylene oxide and propylene oxide to form cationic ammonium moieties in polyurethanes.
It has been known for some time that water dispersible polyurethane compositions can be prepared and used to form films. Various procedures have been disclosed in the literature for making polyurethanes water soluble without diminishing the film forming capabilities of the polyurethanes.
U.S. Pat. No. 3,470,310 (Dietrich et al.) describes the preparation of water dispersions of polyurethanes which contain salt type groups bonded into the polyurethane.
U.S. Pat. No. 3,873,484 (Bluestein et al.) discloses aqueous dispersions of polyurethanes prepared from a quaternized polyurethane prepolymer prepared by reacting from 0.6 to 1.2 equivalents of an alkoxylated diol; one hydroxyl equivalent of an N-alkyl dialkanolamine; about 4 equivalents of an organic diisocyanate and quaternizing with 0.5 equivalents of a dialkyl sulfate quaternizing agent. This quaternized polyetherurethane is chain extended to form a polyurethane-urea and dispersed in water in the presence of a nonionic surfactant belonging to the class of alkoxylated long chain alkyl phenols having an HLB of between about 14 and 16.
The use of dialkyl sulfates, such as dimethyl sulfate, and alkyl halides, such as chloroacetoamide, to quaternize tertiary nitrogen atoms is well known. These compositions, however, possess undesirable characteristics limiting their use in the preparation of cationic polyurethanes.
Dimethyl sulfate, an often used dialkyl sulfate, is highly toxic and difficult to use on a large scale. Alkyl halides such as chloroacetamide are corrosive and require the use of expensive equipment, such as special types of stainless steel.
Therefore a general object of the present invention is to provide a method of preparing cationic polyurethane compositions.
Another object of the present invention is to provide a method of preparing quaternary ammonium salt intermediates.
Another object of the present invention is to provide a process for the preparation of quaternary amines containing reactive hydroxyl groups by a method that avoids the use of corrosive or toxic reactants.
Another object of the present invention is to provide new quaternized polyurethane compositions.
Another object of the present invention is to provide water dispersible polyurethane polymers.
Another object of the present invention is to provide polyurethane compositions that form stable films.
Other objects of the present invention will become apparent from the ensuing description.
SUMMARY OF THE INVENTION
A quaternary ammonium salt is prepared by reacting a tertiary amine, particularly a hydroxyalkyl substituted dialkylamine, with a slight molar excess of an alkylene oxide in the presence of a strong acid. The reaction product, N-di(hydroxyalkyl) N-dialkyl quaternary ammonium salt can be used to prepare other compounds such as polyurethanes by reacting the quaternized bis hydroxy alkyl amine with a molar excess of a polyisocyanate and chain extending the resulting prepolymer with an active hydrogen containing compound such as an amine or water to form a stable latex. Alternatively a polyurethane composition containing tertiary amine moieties can be reacted with a molar excess of an alkylene oxide in the presence of a strong acid to form a cationic polyurethane with pendent hydroxy alkyl groups which can then be chain extended to form a stable dispersion.
DETAILED DESCRIPTION
The present invention is directed to a method for forming quaternary ammonium salts by reacting a tertiary amine moiety with an excess of an alkylene oxide in a system comprising a strong acid. More particularly, the present invention provides methods for forming isocyanate reactive quaternary ammonium compounds. These quaternary compounds are of particular value in the preperation of cationic polyurethanes. Additionally, the present invention provides methods for the synthesis of novel cationic polyurethanes containing pendent hydroxy alkyl groups from polyurethanes containing tertiary nitrogen groups.
The present invention provides new quaternary ammonium salts. These compositions are represented by the following formula:
wherein R and R′ are each independently selected from, in general, alkyl groups having from 1 to about 10 carbon atoms, phenyl, and substituted phenyl groups; the carbon atoms can be linear, in the form of cyclical rings of hydrocarbons or can be heterocyclic; preferably R and R′ will be alkyl groups having about 1 to 4 carbon atoms and more preferably R and R′ will be methyl or ethyl groups;
R″ is selected, in general, from hydrogen, alkyl groups having from 1 to about 10 carbon atoms, cycloalkyl groups having from 5 to 7 carbon atoms in the cycloalkyl group and aryl groups; preferably R″ is H or methyl;
R′″ is, in general, selected from hydrogen, methyl, ethyl, phenyl, aryl, and substituted alkyls such as cyano or nitro substituted alkyls and the like;
m and n are integers independently selected from 0 to about 15; and,
X is the ion of a strong acid, i.e., an acid having a pK
a
<3 such as F
−
, Br
−
, Cl
−
, SO
3
−
, NO
3
−
, COO
−
etc., with SO
3
−
being preferred.
The quaternary ammonium salts represented by Formula I can be prepared by reacting a tertiary amine with a molar excess of an alkylene oxide having the structural formula:
(wherein R″ is as previously defined) in the presence of a relatively strong acid.
Preferred alkylene oxides are ethylene oxide and propylene oxide. In order for the product to be useful in the present invention, in general, the acid used to prepare the quaternary ammonium intermediate should have a pk
a
of about 3 or less. Examples of useful acids are nitric, methane sulfonic, sulfuric, p-toluene sulfonic, cyano acetic, nitrophenylacetic, hydrohalide acids such as hydrochloric, and the like.
The tertiary amine reactant used in the present method can be selected from amines having various substituents depending upon the desired end use of the quaternary ammonium salt product. Where the product is to be used in the preparation of cationic polyurethane compositions, tertiary amines having the following structural formula are preferred:
wherein R, R′ and R″ are as previously defined.
The extent to which a molar excess of alkylene oxide is used in the reaction will determine to some degree the size of the molecule. In general, increasing the amount of alkylene oxide increases the number of oxide groups in the product. Thus by use of large excesses of an alkylene oxide, quaternary ammonium salts wherein m and n in Formula I are up to about 15 can be obtained. This reaction can conveniently be performed at temperatures between about 50° C. and about 100° C., although higher or lower temperatures can be used. This reaction can be performed in water or in any polar organic solvent such as dimethyl sulfoxide, N-methyl pyrolidone and ethylene glycol. Water is the preferred solvent.
The following examples illustrate the preparation of the quaternized ammonium salts and the preparation of cationic polyurethanes therefrom.
REFERENCES:
patent: 4305858 (1981-12-01), Reischl
Baranowski Thomas R.
Bechara Ibrahim
Cook Alex McFarron Manzo Cummings & Mehler, Ltd.
Niland Patrick D.
Witco Corporation
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