WO2001048021A1

WO2001048021A1 - Highly charged cationic cellulose ethers

Info

Publication number: WO2001048021A1
Application number: PCT/US2000/035615
Authority: WO
Inventors: James Vincent Gruber
Original assignee: Union Carbide Chemicals & Plastics
Priority date: 1999-12-29
Filing date: 2000-12-28
Publication date: 2001-07-05
Also published as: AU2464501A

Abstract

Highly charged cationically modified cellulose ethers having cationic substitution levels of at least about 3.0 wt.% are disclosed. The cationically modified cellulose ethers are useful, for example, in personal care formulations, e.g., shampoo. Methods for manufacturing the cellulose ethers are also disclosed.

Description

HIGHLY CHARGED CATIONIC CELLULOSE ETHERS

Field of the Invention

The present invention generally relates to cellulose ethers and

more specifically relates to cellulose ethers which are water-soluble

and highly substituted with cationic substituents and methods for

their preparation.

BACKGROUND OF THE INVENTION

Water-soluble cellulose ethers have been employed in a wide

variety of applications, such as, for example, in personal care

applications such as pharmaceutical and cosmetic compositions, and

industrial applications such as viscosity adjusters, suspension aids, oil

field drilling and fracturing materials and adhesion promoters.

Cationic modification of cellulose ethers is desirable particularly

when the cellulose ethers are used in personal care applications, e.g.,

for enhanced substantivity to skin and hair. Such cationic

modification is also desirable for pharmaceutical applications, e.g.,

especially in applications requiring mucoadhesion such as eye

medication and buccal drug delivery systems. Cationic modification is

also desirable for certain industrial applications, e.g., flocculation of

fines in water treatment, binders in paper manufacturing and adhesion promotion to siliceous materials, all of which are affected by

the substantive properties of the polymer.

Methods for manufacturing water-soluble, cationic cellulose

ethers are well known in the industry. Generally speaking, these

methods involve reactions which are multi-phased. Typically, for

example, the reactions will occur in such a fashion that the cellulose

ether is slurried into an aqueous liquid which is a non-solvent for the

cellulose ether where it reacts with a cationic reagent to afford the

water-soluble, cationic cellulose ether. While attempts have been

made to manufacture highly-charged cationic cellulose ethers, the

methods employed typically involved the use of water immiscible

organic solvents which are typically volatile components, can be toxic

and are thus undesirable. Alternatively, proposed methods involved a

reaction in a dry state where the cellulose ether is reacted with the

cationizing reagent under substantially dry, i.e., no solvent, conditions

and generally require an inorganic flow aid material, such as, for

example, silica gel to aid in mixing. One difficulty with such dry

methods generally lies in the ability to adequately purify the final

product because of the presence of the added flow aid agent.

Purification often cannot be accomplished without the use of washing

solvents which essentially defeats the purpose of preparing the

polymer in a dry state. When cationic cellulose ethers are made in a multi-phased

slurried fashion, the reaction typically requires addition of the cationic

reagent as a liquid product. One common cationizing reagent sold

commercially is glycidyltrimethylammonium chloride, also known in

the art as (2,3-epoxypropyl)trimethylammonium chloride, which is

commercially available as a 70 weight percent ("wt. %") aqueous

solution, i.e., 70 wt. % cationic reagent ("solids"). Interestingly, under

the typical multi-phase slurry reaction conditions employed to make

cationic cellulose ethers, when the aqueous cationizing reagent is used

to cationize the cellulose ether, an interesting phenomena occurs. That

is, as the treatment level of cationizing reagent exceeds about 1.0%,

the amount of cationic reagent which actually reacts with the polymer

levels off This phenomena creates a problem in the industry by

limiting the amount of cationic substituent which can be derivatized

onto the cellulose ether. More specifically, as the cationic reagent is

added to the reaction, water is also added which ultimately dilutes the

aqueous non-solvent reaction medium to the point that reaction

efficiencies level off. It is unavoidable to add this additional water

because it is present in the aqueous cationic reagent. Furthermore,

the continued addition of aqueous reagent in an attempt to increase

the cationic charge introduces more water into the reaction medium.

The increased amount of water promotes the dissolution of the polymer which often yields a gooey, intractable mass of polymer. Although

increasing the solids concentration of the cationic reagent, e.g., to 90

wt. % solids, may help alleviate the problem, such products are

generally not commercially available, presumably due to difficulties in

manufacturing and handling such products. As a result of this dilution

phenomena, cationic cellulose ethers of greater than 2.2% cationic

substituent, e.g., nitrogen, have not been available.

However, cationic cellulose ether with higher cationic charges,

e.g., at least about 3.0 wt %, can provide enhanced substantive

properties relative to cellulose ethers with lower cationic charge levels.

There exists, therefore, a need for such highly charged cationic

cellulose ethers and a method to manufacture such cellulose ethers

using common aqueous cationic reagents, e.g., 70 wt % solids, typical

reaction solvents and standard reaction equipment. Such new cationic

cellulose ethers may be useful in a variety of applications.

SUMMARY OF THE INVENTION

In accordance with the present invention, highly substituted

cationic cellulose ethers are provided. The cellulose ether derivatives

of the present invention can be manufactured having at a substitution

level of at least about 3.0 wt % cationic substituent, for example, using

commonly available aqueous cationic reagents, e.g., 70 wt % solids. The methods involve the sequential reaction of cellulose ethers with

the aqueous cationic reagents whereby water is removed between

reaction steps. Advantageously, the cationic cellulose ethers can be

prepared, in standard commercial equipment, using the multi-phase

slurry technology, preferably without the use of flow aids. Quite

surprisingly, it has been found that these can be highly charged,

cationic cellulose ethers of the present invention can have rheological

and performance properties which are unexpectedly different and often

superior to the cellulose ethers of lower cationic charge, especially in

personal care formulations.

DETAILED DESCRIPTION OF THE INVENTION

Cellulose ethers suitable for use in accordance with the present

invention include etherified derivatives of cellulose. Typical cellulose

ethers include for example, hydroxyethyl cellulose, hydroxypropyl

cellulose, methyl cellulose, hydroxypropyl methyl cellulose,

hydroxyethyl methyl cellulose, carboxymethyl cellulose, hydroxyethyl

carboxymethyl cellulose and the like. Preferred cellulose ethers

include hydroxyethyl cellulose and hydroxypropyl cellulose. Cellulose

ethers such as those described above are readily commercially

available. Alternatively, such cellulose ethers can be prepared from

cellulose by methods known to those skilled in the art. Ether substituents suitable for use in accordance with the

present invention comprise ethers preferably having 2 to 4 carbon

atoms per molecule. Typically, the ether substituent is derivatized

onto the cellulose by reacting the cellulose with an alkylene oxide such

as ethylene oxide, propylene oxide or butylene oxide, preferably

ethylene oxide. The amount of ether substitution is typically from

about 1.5 to 6 and preferably from about 2 to 4 moles of ether

substituent per mole of cellulose ether. Further details concerning the

manufacture of such cellulose ethers are known to those skilled in the

art.

The molecular weight of the cellulose ethers suitable for use in

accordance with the present invention typically ranges from about

10,000 to 2,000,000 grams per gram mole and preferably ranges from

about 80,000 to 1,500,000 grams per gram mole. As used herein, the

term "molecular weight" means weight average molecular weight.

Methods for determining weight average molecular weight of cellulose

ethers are known to those skilled in the art. One preferred method for

determining molecular weight is low angle laser light scattering. The

viscosity of the cellulose ethers typically ranges from about 5 to 6000

centipoise, preferably from about 100 to 3000 centipoise. Unless

otherwise indicated, as used herein, the term viscosity refers to the

viscosity of a 1.0 weight percent aqueous solution of polymer measured at 25°C with a Brookfield viscometer. The average particle size of the

cellulose ethers is not critical, but is preferably from about 0.01 to 1000

microns and more preferably from about 50 to 400 microns.

The ionic nature of the cellulose ethers of the present invention

is not critical. The charge can be cationic, anionic, amphoteric or

nonionic. It is typically preferred, however, that the ionic charge be

cationic, anionic and more preferably nonionic. Those skilled in the art

will recognize that if the starting cellulose ether is anionic, the

resulting reaction product upon treatment with the cationizing reagent

is actually an amphoteric polymer, containing both anionic and

cationic species on the same cellulose ether backbone. Further details

concerning the substituents and methods for modifying the ionic

character of cellulose ethers are known to those skilled in the art.

In addition, the cellulose ethers may be derivatized with other

substituents, e.g., hydrophobically-modified. Hydrophobic substituents

suitable for use in accordance with the present invention comprise an

alkyl or arylalkyl group having about 8 to 18 carbon atoms, preferably

from about 10 to 18 carbon atoms and more preferably from about 12

to 15 carbon atoms. As used herein, the term "arylalkyl" group means

a group containing both aromatic and aliphatic structures. Many

hydrophobe-containing reagents suitable for use as hydrophobic

substituents are commercially available and resulting hydrophobically- modified cellulose ethers are known as well such as disclosed in U.S.

Pat. Nos. 4,228,277, 4,663,159 and 4,845, 175.

The cationic cellulose ether derivatives of the present invention

are water-soluble. As used herein, the term "water-soluble" means

that at least 1 gram, and preferably at least 2 grams of the cellulose

ether derivatives are soluble in 100 grams of distilled water at 25°C

and 1 atmosphere. The extent of water solubility is control by the level

of substituent groups, including the cationic groups, attached to the

cellulose derivative. Techniques for varying the water solubility of

cellulose ethers are known to those skilled in the art.

Typically, the cationic substituents suitable for use in the

present invention comprise nitrogen. Preferably the cationic

substituents are selected from the group consisting of alkyl substituted

nitrogen compounds, aryl substituted nitrogen compounds or alkyl-aryl

substituted nitrogen compounds. Often, the cationizing reagents used

to provide the cationic substituents are alkyl substituted nitrogen

halides such as, for example, (2,3-Epxoypropyl) trimethyl ammonium

chloride available as a 70 wt % solids solution from Degussa

Corporation as QUAB™ 151.

Preferably, the cationic substituents suitable for use in

accordance with the present invention have the formula:

where;

each Ri, R₂, and R3 is CH3 or C2H5;

R₄ is CH2CHOHCH2 or CH2CH2; and

A2 is a halide ion.

Preferably, Ri, R2, and R3 are CH3. Preferably, R₄ is

CH2CHOHCH2. Chlorine is a preferred halide ion. Other cationic

substituents may also be used in accordance with the present

invention. In addition, Ri, R2, or R3 can also be an alkyl or arylalkyl

group having about 8 to 18 carbon atoms.

Preferably, the substitution level of the cationic substituents on

the cellulose ethers of the present invention ranges from about 3.0 to

8.0 wt % of the cationic substituent, e.g., cationic nitrogen based on the

total weight of the cellulose ether. More preferably, the percent

cationic nitrogen for the cationic cellulose ethers of the present

invention is from about 3.0 to 6.0 wt %. Most preferably, the percent

cationic substituent is from about 3.0 to 5.0 wt %. As used herein,

percent cationic substituent is the percentage of cationic substituent

covalently bound to the anhydroglucose monomers of the cellulose ether. The substitution level can be determined by a number of

different methods known to those skilled in the art. For example, a

particularly preferable method for determining percent cationic

nitrogen is the Kjeldahl method as disclosed in Organic Analysis,

volume III. [Interscience Publishers, New York], pp., 136-141.

Determining the amount of covalently bound nitrogen can be

accomplished, for example, by dialyzing the derivatized polymer

against distilled water using dialysis membranes such as those

supplied by the Spectrum company, Houston, Texas. Dialysis allows

for the removal of the unreacted, low molecular weight nitrogen

containing species and provides derivatives which contain only

nitrogen reacted to the polymer. In addition, the level of covalent

cationic substituent can be determined by nuclear magnetic resonance

spectroscopy (NMR), the use of which is known to those skilled in the

art.

Typically, the cationically-modified cellulose ethers of the

present invention are prepared by: (i) reacting a cellulose ether with a

first aqueous cationizing reagent to form a first reaction product

comprising a first cationic cellulose ether and water; (ii) removing at

least a portion of the water from the first reaction product, e.g., by

centrifuging, to form a dried reaction product comprising the first

cationic cellulose ether; and (iii) reacting the dried reaction product with a second aqueous cationizing reagent to form a second reaction

product comprising a second cationic cellulose ether having a higher

substitution level of cationic substituent than the first cationic

cellulose ether. Typically, the first cationic cellulose ether has a

substitution level of less than about 2.5 wt % of the cationic

substituent based on the total weight of the cellulose ether. The first

cationizing agent and the second cationizing agent can be the same or

different. Also, typically the dried reactor product comprises from

about 0.1 to 50 wt % water based on the total weight of the dried

reaction product.

In one aspect of the present invention, the highly substituted

cationic cellulose ether derivatives of the present invention are formed

in a sequential series of reaction steps substantially free of any type of

inorganic flow aid materials, such as, for example, silica gel, in which

the final product from the preceding reaction becomes the starting

material for the next reaction. As used herein, the term "substantially

free" means less than about 5 wt %, preferably less than about 2 wt %

and more preferably less than about 1 wt % inorganic flow aid material

based on the total weight of the cationic cellulose ether and the

inorganic flow aid material. Such reactions could, in theory, be

continued for many multiple sequential steps. However, for practical

purposes, it is reasonable to expect that adequate substitution of the cationic cellulose ethers of the present invention can be accomplished

in two sequential steps. Thus, a cellulose ether is typically treated in

one sequential step with a measured amount of the cationizing

reagent, the product is isolated and this product becomes the starting

material for the next sequential reaction. In this fashion, 70 wt %

aqueous cationic reagent, for example, can be used without adverse

interference with reaction efficiency at higher substitution levels. As

an alternative to the initial sequential reaction described above, one of

the commercially available cationic cellulose ethers with a lower

substitution level, e.g., about 2 wt % cationic nitrogen, can be used as

the starting material. Such cationic cellulose ethers are available, for

example, from Amerchol Corporation under the tradename UCARE^®

Polymer. Particularly preferred for the purposes of the present

invention are UCARE^® Polymers JR-400 and JR-30M which both

contain about 2.2 wt % cationic nitrogen.

In addition, surprisingly it has been found that the sequential

manufacture of the cationic cellulose ethers of the present invention

can be effective to prevent the amount of the aqueous non-solvent from

increasing to the point where dissolution of the cationic cellulose ether

product begins to occur. Efforts to obtain the highly substituted

cationic cellulose ethers of the present invention in a single step by

addition of large quantities aqueous 70 wt % cationic reagent often converts the product into a highly swollen, gooey, intractable mass

which can not be isolated using standard filtration equipment. It has

also been surprisingly found that substituting the cationic cellulose

ethers of the present invention with levels of cationic nitrogen greater

than 3.0 percent can have unusual effect on the aqueous solution

viscosity of the resulting cationic cellulose ethers.

A preferred end-use for cationic cellulose ether derivatives of the

present invention is as a component in personal care compositions

which comprise the cellulose ether derivative and a personal care

ingredient. As used herein, "personal care ingredient" includes, but is

not limited to, active ingredients such as for example, spermicides,

virucides, analgesics anesthetics, antibiotic agents, antibacterial

agents, antiseptic agents, antidandruff agents, vitamins,

corticosteriods, antifungal agents, vasodilators, hormones,

antihistamines, autacoids, kerolytic agents, antidiarrhea agents, anti-

alopecia agents, anti-inflammatory agents, glaucoma agents, dry-eye

compositions, wound healing agents, anti-infection agents, and the

like, as well as solvents, diluents and adjuvants such as, for example,

water, ethyl alcohol, isopropyl alcohol, higher alcohols, glycerine,

propylene glycol, sorbitol, preservatives, surfactants, propellants,

fragrances, essential oils, viscosity adjusters and the like. Such personal care ingredients are commercially available and known to

those skilled in the art.

The amount of the cellulose ether derivatives present in the

personal care composition will vary depending upon the particular care

compositions. Typically, however, the personal care compositions will

comprise from about 0.1 to 99 weight percent of the cellulose ether

derivative of the present invention. Often, the concentration of the

cellulose ether derivative in the personal care composition will range

form about 0.2 to 50 weight percent, and more often from about 0.5 to

10 weight percent based on the personal care composition.

Typical cleansing systems may contain, for example, water and

a surfactant, like ammonium lauryl sulfate and ammonium laureth

sulfate and, auxiliary surfactants like lauramide DEA or cocobetaines,

thickening agents like NaCl, hydroxypropyl cellulose or PEG- 120

methyl glucose dioleate, conditioners like Dimethicone,

Polyquaternium-10 and, or PEG-2M polyethers, pH adjusters like citric

acid or triethylamine and a chelating agent like tetrasodium EDTA.

Likewise, bar soaps may contain, for example, surfactants like

tallowate or cocoate and a feel modifier like glycerin.

Typical aerosol and non-aerosol hairsprays may contain, for

example, a solvent like a low molecular weight alcohol and, or water, a

propellant like dimethylether or a hydrocarbon, a resin like poly(vinylpyrrolidone)/ vinyl acetate copolymer,

poly(vinylmethacrylate)/ methacrylate copolymer, or a latex dispersion

of polymers, a plasticizer like dimethicone copolyol and a neutralizing

agent like aminomethyl propanol.

Typical creams may contain, for example, an oil like mineral oil,

water, an emulsifier like methyl glucose sesquistearate or PEG-20

methyl glucose sesquistearate, a feel modifier like isopropyl palmitate

or PEG-20 methyl glucose distearate, a polyhydridic alcohol like

methyl gluceth-20 and a stabilizer like carbomer.

Typical mousses may contain, for example, a solvent like water

and, or alcohol, a surfactant like oleth-10, a feel modifier like isopropyl

palmitate and a resin like polyquaternium-10 or

poly(vinylmethacrylate)/methacrylate copolymer.

Typical gels may contain, for example, a viscosifying agent like

carbomer, a solvent like water and, or alcohol, a styling resin like

poly(vinylmethacrylate)/vinylmethacrylate copolymer, a neutralizing

agent like aminomethyl propanol and a feel modifier like methyl

gluceth-20.

Typical ophthalmic compositions, such as, for example, synthetic

tears, ophthalmic lubricants, or pharmaceutical containing delivery

systems, are neutrally buffered and isotonic. Levels of isotonic salts of

up to about 0.9 parts by weight and up to 5 parts of the active ingredient are often included. Typical inorganic isotonic ingredients

include, for example, sodium chloride, boric acid, borax, etc., while

typical natural isotonic ingredients include sugars such as dextrose,

mannitol and sorbitol or polymeric sugars such as, for example,

hyaluronic acid. The pH of these solutions can vary widely from 3 to 9

and is typically from about 6 to 8. Other common ophthalmic additives

include, for example, viscosity adjusters, e.g., hydroxyethyl cellulose,

propylene glycol, glycerols, carbonates and bicarbonates and

ethylenediaminetetraacetic acid (EDTA).

Further details concerning the ingredients, amounts of

ingredients and preparation methods of personal care compositions

such as described above are known to those skilled in the art.

It has been surprisingly found that the highly charged cationic

cellulose ethers of the present invention have unusual solubility

properties in a typical surfactant shampoo formulation when compared

to their corresponding lower charged derivatives of comparable

molecular weight. More specifically, it has been found that when the

highly charged cationic cellulose ethers of the present invention are

dissolved into water and mixed into a shampoo surfactant mixture

containing ammonium lauryl sulfate, sodium lauryl ether sulfate and

cocamidopropylbetaine the formulation becomes nearly opaque, whereas the low charged cationic cellulose ethers known in the art

provide clear formulations.

Without being bound by theory, it is believed that the opaque

nature of the polymer/surfactant mixture may be related to the

development of a coacervate phase in the surfactant solution.

Coacervate formation is dependent upon a variety of criteria such as

molecular weight, concentration, and ratio of interacting ionic

materials, ionic strength (including modification of ionic strength, for

example, by addition of salts), charge density of the cationic and

anionic species, pH, and temperature. Coacervate systems and the

effect of these parameters have been described, for example, by J.

Caelles, et al., "Anionic and Cationic Compounds in Mixed Systems",

Cosmetics & Toiletries, Vol. 106, April 1991, pp 49-54, C. J. van Oss,

"Coacervation, Complex-Coacervation and Flocculation", J. Dispersion

Science and Technology, Vol. 9(5,6), 1988-89, 561-573, and D. J.

Burgess, "Practical Analysis of Complex Coacervate Systems", J. of

Colloid and Interface Science, Vol. 140, No. 1, November 1990, pp 227-

238, which descriptions are incorporated herein by reference.

It is believed to be particularly advantageous for the cationic

polymer to be present in a shampoo in a coacervate phase, or to form a

coacervate phase upon application or rinsing of the shampoo to or from

the hair. Complex coacervates are believed to more readily deposit on the hair as suggested, for example, in PCT WO 98/18434 published

October 1997. Thus, in general, it is preferred that the cationic

polymer exist in the shampoo as a coacervate phase or form a

coacervate phase upon dilution. If not already a coacervate in the

shampoo, the cationic polymer will preferably exist in a complex

coacervate form in the shampoo upon dilution with water

Techniques for analysis of formation of complex coacervates are

known in the art. For example, microscopic analysis of the shampoo

compositions, at any chosen stage of dilution, can be utilized to identify

whether a coacervate phase has formed. Such coacervate phase will be

identifiable as an additional emulsified phase int he composition. The

use of dyes can aid in distinguishing the coacervate phase from other

insoluble phase dispersed in the composition.

The characteristics of the opaque shampoos provides these

shampoos with new and unexpected cosmetically significant

properties. For example, it has been found that hair tresses treated

with shampoos containing a commercially available cationic cellulose

ether and one containing a highly charged variant made by the

method of the present invention that is of comparable molecular

weight shows improvements in wet-combing force reductions and

detangling when compared to either the simple shampoo base without

cationic polymer or a similar shampoo made with the lower charged cationic cellulose of comparable molecular weight. Methods for

measuring combing force are known to those skilled in the art.

Likewise, it has been surprisingly found that hair tresses

treated with similar shampoos containing a highly charged cationic

cellulose polymer that are curled and dried and subsequently tested

for curl retention using standard methods known to those skilled in

the art show improvements in curl retention when compared to

tresses treated with either the simple shampoo base or with a

shampoo containing a cationic cellulose ether of comparable molecular

weight but lower cationic charge.

In addition, the cationic cellulose ethers of the present

invention, because of their higher charge, may find applications as

mucoadhesives in buccal drug delivery systems and as agents useful in

microencapsulation as part of a polyelectrolyte complex. Polymers

useful as mucoadhesives must have substantivity for the mucous

membranes such as those lining, for example, the mouth, nose, vaginal

and rectal regions of the body. As part of a polyelectrolyte complex, the

highly charged cationic cellulose derivatives of the present invention

will typically be complexed with a complimentary anionic polymer such

as, for example, alginic acid or xanthan. Such complexes may take a

variety of forms, but most typically will occur as, for example, sheets, foams and microcapsules in which the active therapeutic ingredient is

embedded within the polyelectrolyte complex matrix.

Further details concerning the ingredients, amounts of

ingredients and preparation methods of mucoadhesive compositions

and polyelectrolyte complexes such as described above are known to

those skilled in the art.

EXAMPLES

The following examples are provided for illustrative purposes

and are not intended to limit the scope of the claims which follow.

The following ingredients were used in the Examples.

UCARE^® Polymer JR-400-cationic hydroxyethyl cellulose with a

molecular weight of approximately 400,000, derivatized with

approximately 1.8 percent cationic nitrogen. Available from Amerchol

Corporation, Edison, NJ.

UCARE^® Polymer LK-400- cationic hydroxyethyl cellulose with

a molecular weight of approximately 400,000, derivatized with

approximatelyO.5 percent cationic nitrogen. Available from Amerchol

Corporation, Edison, NJ.

UCARE^® Polymer LR-400- cationic hydroxyethyl cellulose with a

molecular weight of approximately 400,000, derivatized with approximately 1.0 percent cationic nitrogen. Available from Amerchol

Corporation, Edison, NJ.

UCARE^® Polymer JR-30M-cationic hydroxyethylcellulose with a

molecular weight of approximately 900,000, derivatized with 1.8-2.2

percent cationic nitrogen. Available from Amerchol Corporation,

Edison, NJ.

QUAB^® 151-Glvcidyltrimethylammonium chloride available as a

70% aqueous solution. Available from Degussa, Ridgefield Park, NJ.

2-Propanol-Available from Fisher Scientific, Fair Lawn, NJ.

CELLOSIZE^® QP-4400-Hvdroxvethvl cellulose of approximately

400,000 molecular weight. Available from Union Carbide Corporation,

Danbury, CT.

Acetic acid-Available from Aldrich Chemical Co., Milwaukee,

WI.

Hair Tresses-Virgin Brown, and Bleached Blond tresses

available from DeMeo Brothers, New York, NY.

EXAMPLES 1-5 PREPARATION OF CATIONIC CELLULOSE ETHERS FROM A

SINGLE TREATMENT.

In a 500 ml round bottom flask equipped with a mechanical

stirrer, a nitrogen sparging tube, an addition funnel and a condenser

was placed 141 grams of 2-ρropanol and 24 grams of water. To this was added 30 grams of CELLOSIZE QP-4400 and the resulting slurry

was purged for 1 hour with nitrogen. After 1 hour, 4.5 grams of a 20%

NaOH solution was added and the mixture was stirred for an

additional 30 minutes while purging with nitrogen. To this reaction

was added 0.1% of QUAB 151 (based on the weight of the CELLOSIZE

added) and the reaction was warmed to 55°C for 1 hour and kept at

55°C for an additional 90 minutes. The reaction was then cooled to

25°C and 2.4 grams of glacial acetic acid was added to neutralize the

caustic. The reaction mixture was filtered through a Buchner funnel

fitted with a #1 Whatman filter paper and the resulting solid product

was reslurried in 300 mis of aqueous 2-propanol (of the same ratio as

used in the reaction). The resulting product was refiltered and dried to

afford the derivatized cellulose ether.

One gram of the resulting product was dissolved in 100 mis of

distilled water and the resulting solution was placed into a Spectra/Por

7 dialysis membrane (available from the Spectrum company, Houston,

TX) with a MWCO of 1000. The polymer was dialyzed against distilled

water for three days with daily changes of the distilled water. The

resulting solution was lyophilized to dryness and the resulting polymer

analyzed for nitrogen using the Kjeldahl method. This particular

sample had 0.4% cationic nitrogen. In a similar fashion, EXAMPLES 2-5 were run with 0.2, 0.65, 0.9 and 1.1% QUAB 151. The resulting

corresponding percent nitrogen values are shown in Figure 1.

These Examples demonstrate that the addition of the aqueous

QUAB 151 eventually results in a leveling off of the percentage of

bound cationic nitrogen (indicative of the amount of reagent which

reacts with the cellulose ether) and that treatments as high as 1.1% do

not afford products with greater than 3.0% bound cationic nitrogen.

The product from Example 3 is typical of the types of cationic cellulose

ethers currently commercially available.

EXAMPLES 6-8 PREPARATION OF CATIONIC CELLULOSE ETHERS FROM A

DOUBLE TREATMENT

Examples 6-8 were run exactly as described above for Examples

1-5 except that UCARE Polymer JR-400 with 1.8% cationic nitrogen

(this product is similar to the material obtained from Example 3 above)

already bound to the polymer was used as the starting material. In

Example 6, 0.65% QUAB 151 was added to the reaction mixture based

on the weight of the starting UCARE Polymer JR-400. In Example 7,

1.1% QUAB 151 was used, and in Example 8, 2.0% QUAB 151 was

used. The data for the percent bound nitrogen for each of these

Examples is shown in Figure 1. In addition, the reaction mixture for Example 8, where 2.0%

QUAB 151 was used, was isolated as a spongy swollen mass and was

difficult to filter. This demonstrates that at QUAB 151 addition levels

greater than 2.0%, one can expect that the reaction non-solvent

(aqueous 2-propanol) will become sufficiently saturated with water as

to begin swelling the cationic cellulose ether making the final product

intractable.

Examples 6-8 again demonstrate that with increasing amounts

of aqueous QUAB 151, a leveling effect occurs and percent of bound

nitrogen values greater than 4.2 cannot be achieved even in a double

treatment.

EXAMPLE 9 PREPARATION OF CATIONIC CELLULOSE ETHERS FROM A

TRIPLE TREATMENT

Example 9 was run using 0.65% QUAB 151 (based on the weight

of the starting cationic cellulose ether) starting with the product obtain

from Example 7 which was a double-treated cationic cellulose ether

with a percent bound nitrogen of 3.9. The reaction was run exactly as

described above for Examples 1-5. The resulting product obtained had

5.0% bound cationic nitrogen after the triple treatment as can be seen

below in Figure 1. EXAMPLE 10

PREPARATION OF HIGHLY CHARGED CATIONIC

HYDROXYETHYL CELLULOSE OF HIGHER MOLECULAR

WEIGHT

A sample of highly charged cationic cellulose ether was made

using the process described in Example 1. This product was made by

twice treating UCARE Polymer JR-30M using the process described in

Example 1. The resulting product contained 3.6 % cationic nitrogen as

determined by Kjeldahl analysis.

EXAMPLES 11-15 SHAMPOO APPEARANCE

Typical shampoos were made using the formulations shown in

Table 1. The shampoos made with the cationic cellulose ethers of low

charge were clear. The shampoos made from the highly charged

cellulose ethers of the present invention appeared opaque.

Table 1.

Examples 11-15

Shampoo Formulations and Appearance

(Data appears as weight percent of ingredient)

Table 1 (continued)

EXAMPLES 16-17 WET COMBING STUDIES

Bleached blond hair tresses were washed using the shampoos

described in Examples 11, 12, 13, 14 and 15. Example shampoos 11

and 13 contain polymers of similar molecular weight but different

charge levels and Example shampoos 12 and 14 contain cationic

polymers of similar molecular weights (higher than those found in

Examples 11 and 13) but of different charge levels. Example 15 is a

shampoo without cationic polymer. In each case, a five gram tress was

washed with 0.2 grams of the shampoo for one minute, the tress was

rinsed by dipping in 3 separate 600ml beakers of tap water 4 times and

then combed briefly to align the fibers. Each tress was dipped five times into a beaker containing 600 mis of tap water to allow slight but

controlled entanglement of the hair fibers. The excess water was

removed from the tress by squeezing with the fingers twice. The wet

tress was placed onto a Miniature Tensile Tester Dia-Strona and the

force and energy required to pass the comb through the tress was

measured. The results given as percentage combing force reduction

are shown in Tables 2 and 3 below.

Table 2.

Combing Force results for Tresses Prepared with Shampoo Examples 11, 13 and 15.

Example # 2+ std 2- std % Change

Example 11 64.6 25.2 44.9

Example 13 89.6 88.4 89

Example 15 48.5 11.1 29.8

Table 3.

Combing Force Results for Tresses

Prepared with Shampoo

Examples 12, 14 and 15.

Example # 2+ std 2- std % Change

Example 12 80.5 73.7 77.1

Example 14 85.7 68.9 77.3

Example 15 48.5 11.1 29.8 EXAMPLES 18-19 CURL RETENTION STUDIES

Virgin Brown hair tresses all from a single batch of hair were

cut to 27 cm length and prewashed with a shampoo containing only a

non-ionic surfactant. A total of three tress samples per measurement

were washed as described above for Examples 16-17 with shampoos

from EXAMPLES 11, 12, 13 and 14. The resulting tresses were rinsed

with warm water and rolled onto 1 inch curlers. The curled tresses

were allowed to dry naturally overnight. The curlers were than gently

removed from each curl, taking care not to damage the curled structure

and the tresses were hung in a specially designed chamber which

maintains the temperature at 20°C and the relative humidity at 90%.

The tresses were than allowed to equilibrate in the chamber and the

amount of curl droop was measured using a grid set behind the tresses.

The results of the tress studies are shown below in Figures 3 and 4

which show the average percent of curl retention retained by each tress

over a thirty minute time period. Table 4 shows the results for

Example shampoos 11 and 13 and Table 5 shows the results from

Example shampoos 12 and 14. In this way, polymers of similar

molecular weight are compared to one another. Table 4.

Percentage Curl Retention for Tresses

Prepared from Shampoo

Examples 11 and 13.

Table 5.

Percentage Curl Retention for Tresses

Prepared from Shampoo

Examples 12 and 14.

EXAMPLE 20

AQUEOUS VISCOSITY OF HIGHLY

CHARGED CATIONIC CELLULOSE ETHERS

One percent aqueous solutions of three commercially available

cationic cellulose ethers, UCARE^® Polymers LK-400, LR-400, and JR-

400 and three highly charged cationic cellulose ethers of the present

invention, EXAMPLE 6, EXAMPLE 7 and EXAMPLE 8 were examined

for their viscosity verses shear rate behavior by using a Bohlin VOR

Rheometer [Bohlin Instruments, Cranbury, NJ]. Measurements were

taken using a C25 concentric cylinder geometry at 30°C. Each polymer

has approximately the same molecular weight. The data for the

measurements is shown in Figure 2. In addition to the specific aspects of the invention described

herein, those skilled in the art will recognize that other aspects are

intended to be included within the scope of the claims which follow.

For example, polysaccharides other than cellulose which can be

derivatized with ether substituents and cationic substituent may be

employed.

Claims

Claims:

1. A water-soluble, cationically modified cellulose ether characterized in that said cellulose ether comprises from about 1.5 to 6 moles of an ether substituent per mole of cellulose ether and is further substituted with a cationic substituent in an amount of at least about 3.0 wt % cationic substituent based on the total weight of the cellulose either.

2. The cellulose ether of claim 1 wherein the cationic substituent comprises nitrogen.

3. The cellulose ether of claim 2 wherein cationic substituent is selected from the group consisting of alkyl substituted nitrogen compounds, aryl substituted nitrogen compounds and alkyl-aryl substituted nitrogen compounds.

4. The cellulose ether of claim 1 having a weight average molecular weight of from about 10,000 to 2,000,000 grams per gram mole.

5. The cellulose ether of claim 1 wherein the amount of cationic substituent is from about 3.0 to 8.0 wt % cationic substituent.

6. The cellulose ether of claim 1 wherein the cellulose ether is selected from the group consisting of hydroxyethyl cellulose, hydroxypropyl cellulose, methyl cellulose, hydroxypropyl methyl cellulose, hydroxyethyl methyl cellulose, hydroxyethyl carboxymethyl cellulose and mixtures thereof.

7. The cellulose ether of claim 6 wherein the cellulose ether is hydroxyethyl cellulose.

8. A personal case composition containing a water-soluble, cationically modified cellulose ether according to claim 1 and at least one personal care ingredient.

9. A method for manufacturing a cationically modified cellulose ether comprising:

(i) reacting a cellulose ether with a first aqueous cationizing reagent to form a first reaction product comprising a first cationic cellulose ether and water;

(ii) removing at least a portion of the water from the first reaction product to form a dried reaction product comprising the first cationic cellulose ether; and

(iii) reacting the dried reaction product with a second aqueous cationizing reagent to form a second reaction product comprising a second cationic cellulose ether having a higher substitution level of cationic substituent than the first cationic cellulose ether.

10. The method of claim 9 wherein the first cationic cellulose ether has a cationic substitution level of less than about 2.5 wt % cationic substituent based on the total weight of the cellulose ether.

11. The method of claim 9 wherein the second cationic cellulose ether has a cationic substitution level of at least about 3.0 wt % cationic substituent based on the total weight of the cellulose ether.

12. The method of claim 9 wherein the dried reaction product comprises from about 0.1 to 50 wt % water based on the total weight of the dried reaction product.