Organic compounds -- part of the class 532-570 series – Organic compounds – Carbohydrates or derivatives
Reexamination Certificate
1994-12-23
2002-04-16
Peselev, Elli (Department: 1623)
Organic compounds -- part of the class 532-570 series
Organic compounds
Carbohydrates or derivatives
C536S084000, C536S090000, C536S093000, C536S095000, C536S096000
Reexamination Certificate
active
06372902
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention pertains to novel polysaccharides and their use in latex compositions and processes, and more particularly to polysaccharides having alkyl-aryl hydrophobes, and improved processes for their production in which polysaccharides provide latex compositions with improved rheology and stability.
2. Description of Background Information
Latex compositions typically have additives which modify the rheology or stability of the composition. Polysaccharides, and in particular cellulosics, have been described as additives to latex compositions for various purposes, including as protective colloids, thickeners, stabilizers or other rheology modifiers. For example, U.S. Pat. No. 4,684,704 (Craig) describes latex compositions containing hydrophobically modified, hydroxyethyl cellulose as a protective colloid. U.S. Pat. No. 4,243,802 (Landoll) and U.S. Pat. No. 4,352,916 (Landoll) describe the use of hydrophobically modified, hydroxyethyl cellulose as thickeners, emulsifiers and stabilizers for latex compositions. U.S. patent application Ser. No. 172,432, filed Mar. 24, 1988, entitled “PREPARATION OF AQUEOUS POLYMER EMULSIONS IN THE PRESENCE OF HYDROPHOBICALLY MODIFIED HYDROXYETHYL CELLULOSE”, describes emulsion polymerization processes using hydrophobically modified hydroxyethyl cellulose, including alkyl-aryl-substituted materials.
Polysaccharides having aryl substituents are known. For instance, U.S. Pat. No. 1,451,331 (Dreyfus), U.S. Pat. No. 1,502,379 (Dreyfus), U.S. Pat. No. 1,589,607 (Lilienfeld), and U.S. Pat. No. 1,972,135 (Dreyfus) describe hydroxyethyl cellulose with aralkyl, e.g. benzyl, substitution. Japanese Patent Application Publication No. 82-28003 (Nakamura) describes benzyl substituted, quaternary nitrogen-containing cellulosics in cosmetics. U.S. Pat. No. 4,663,159 (Brode, II et al.) describes water-soluble, cationic polysaccharides containing hydrophobes including aralkyl or alkaryl substituents, having various utilities.
SUMMARY OF THE INVENTION
This invention pertains to polysaccharides with alkyl-aryl hydrophobes and to latex compositions and processes using such polysaccharides. The latex composition contains water, latex polymer and water-soluble polysaccharide having alkyl-aryl hydrophobes. A process for improving the rheology of latex compositions is provided using such polysaccharides. Processes for producing these polysaccharides are also provided. One process comprises reacting a polysaccharide ether with an alkyl-aryl hydrophobe containing compound wherein the ether substitution on the polysaccharide provides an increase in the amount of hydrophobe substitution reacted onto the polysaccharide. Another process comprises reacting a polysaccharide with an alkyl-aryl, hydrophobe-containing glycidyl ether compound.
DETAILED DESCRIPTION OF THE INVENTION
Polysaccharides are generally high molecular weight polymers composed of monosaccharide repeating units joined by glycosidic bonds. Alkyl-aryl hydrophobe substitution of polysaccharides are polysaccharides which have one or more alkyl-aryl substituents, with at least about 10, preferably from about 12 to about 24, and most preferably from about 15 to about 18, carbon atoms in the alkyl-aryl group, i.e. hydrophobe. The aryl portion of the hydrophobe may have one or more aryl rings, which may be fused, carbocyclic or heterocyclic, unsubstituted or substituted with other functional groups, such as halogen, nitro, hydroxyl, amino or other substituents. The alkyl portion of the hydrophobe may be straight or branched chain, cyclic or acyclic, saturated or partially unsaturated, unsubstituted or substituted with other functional groups, such as halogen, hydroxyl or other substituents. Alkyl-aryl hydrophobes include both aralkyl or alkaryl groups. Typical hydrophobes include, but are not limited to, one or more of the following: alkaryl such as t-butylphenyl, nonylphenyl or dodecylphenyl; and aralkyl such as phenylhexyl or naphthyldodecyl. Preferred hydrophobes are nonylphenyl and dodecylphenyl.
The degree of hydrophobe substitution, i.e. DS, defined as the average moles of hydrophobe substituent per mole of polysaccharide repeat unit, may vary depending upon the presence of other substituents, type of hydrophobe and type of polysaccharide. Generally, the DS of the hydrophobe is greater than zero, preferably from 0.001 to about 0.1, and most preferably from 0.005 to about 0.03.
The polysaccharides with alkyl-aryl hydrophobes include polymers of repeating units represented by the structural formula:
In Formula I, for each repeating unit individually:
wherein R
4
is
or a mixture of hydrogen and
R
sacch
is the residue of a polysaccharide repeat unit and may include additional reactive groups, as in xanthan gum;
x is from about 50 to about 20,000;
each y
1
, Y
2
and y
3
is 0 or 1;
each Z
1
, Z
2
and Z
3
is a divalent connecting segment; and
each R
1
, R
2
and R
3
is individually a hydrogen, an unsubstituted or a nitrogen-, oxygen-, sulfur- or carboxyl-containing hydrocarbyl group or R
h
, wherein R
h
is an alkyl-aryl hydrophobe, provided that (1) when R
1
, R
2
or R
3
is hydrogen then y
1
, Y
2
or y
3
, respectively is 0 and (2) one or more repeating units have one or more R
1
, R
2
or R
3
which is R
h
.
In Formula I, Q is preferably oxygen providing anhydroglucose repeat units, and most preferably cellulose. The number of repeat units, defined by x, is preferably from about 50 to about 20,000 and most preferably from about 250 to about 4,000, providing a molecular weight of from several thousand up to several million. The molecular weight of the polysaccharide may be varied using well established procedures, such as controlled degradation.
In Formula I, the ether substituents, i.e. (Z
1
)
y
1
—R
1
, (Z
2
)
y
2
—R
2
and (Z
3
)
y
3
—R
3
, are usually hydrogen with some alkyl-aryl hydrophobes, and preferably hydroxyethyl, present. Since only one or more repeating units must have one or more R
h
, not every polysaccharide repeat unit must have an alkyl-aryl hydrophobe. Generally, only a minor portion of repeat units will have one or more hydrophobes. Typical ether substituents include, but are not limited to, one or more of the following: hydrogen, i.e. —H; unsubstituted hydrocarbyl such as —CH
3
, —CH
2
CH
3
, —CH
2
C
6
H
5
, or —C
16
H
33
; nitrogen-, oxygen-, sulfur- or carboxyl-containing hydrocarbyl such as —CH
2
CH
2
OH; —CH
2
COOH: —CH
2
COO
−
Na
+
or —CH
2
CH
2
O—CH
2
CHOH; alkyl-aryl
hydrophobes with or without connecting segments, including the alkyl-aryl hydrophobes described previously, such as
Preferably the ether substituents also include hydroxyethyl, i.e. —CH
2
CH
2
OH, in an amount sufficient to provide water solubility.
In Formula I, the divalent connecting segment, represented by Z
1
, Z
2
and Z
3
, designates the portion of the ether substituent which is provided between the cellulose ether oxygen, or Q group, and the main portion of the substitutent, such as an alkyl-aryl group. When R
1
, R
2
or R
3
is hydrogen, i.e. when the group represented is an unsubstituted hydroxyl, there is no connecting segment and y
1
, y
2
or Y
3
is correspondingly 0. When R
1
, R
2
or R
3
is not hydrogen, then a connecting segment may or may not be provided. Generally, the connecting segment represents the residual portion of the compound used to provide an alkyl-aryl substitutent on the polysaccharide, which portion is not the alkyl-aryl group per se. Typical connecting segments, when present, include, but are not limited to: unsubstituted or hydroxy-substituted alkyl or alkoxy groups such as methylene, i.e. —CH
2
—, ethoxy, i.e. —-CH
2
CH
2
O—, or glycidyl ethers, i.e.
Preferably, the connecting segment is absent or present as —CH
2
—or most preferably as
The polysaccharide may contain additional substitution, i.e. other than the hydrophobes, such as may be required to provide the requisite water solubility or other properties. The other substituents may be ionic or nonionic providing nonionic, cationic, anionic or amphot
Brode, II George Lewis
Hoy Richard Charles
Partain, III Emmett Malone
Peselev Elli
Union Carbide Corporation
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