liii
`
`Ill Dli
`
`Illl
`
`lM
`
`lOll
`
`liii
`
`Il
`
`ill
`
`1101
`
`ll0
`
`11......
`
`i0i H
`US006231657B1
`Us 6231657 Bi
`May 15 2001
`
`10 Patent No
`45 Date of Patent
`
`58 Field of Search
`
`106/162.8 731
`106/805 426/658
`514/781
`
`56
`
`References Cited
`
`U.S PAIENT DOCUMENTS
`
`448t076
`5964983
`
`11/1984
`
`Herrick
`
`10/1999 Dinand et
`
`162/158
`
`162/27
`
`OTHER PUBLICATIONS
`DWP 1998120374 Bcnchimoi
`Jan 16 1998
`DWP 1999280301 Wiemin Use of amorphous cellu
`Apr 23 1999
`
`composition
`
`lose nanofibrils
`
`et
`
`Viscosity modifier
`
`cited by examiner
`
`Prinary ExaminerDavid Brunsman
`74 Attorney Agent or FirmJean-Louis Seugnet
`57
`ABSTRACT
`
`The invention concems compositions
`containing essentially
`amorphous cellulose naoofibrils carboxyl
`cellulose with
`degree of substitution not more than o.95 as additive and
`in additive
`optiooally at east one co-additive the content
`and optional co-additive being less than 30 wt
`and
`the weight of nanofibrils
`additive
`The
`co-additive
`invention
`preparing such
`compositions consisting
`in adding to
`substantially amorphous nanofibril suspension the additive
`and optionally the co-additives
`then in drying the suspen
`The resulting compositions
`sion thus additivated
`are easily
`redispersable and preserve all
`theft
`
`relative to
`
`and optional
`method for
`
`also concerns
`
`rheologicat properties
`
`26 Claims No Drawings
`
`12 United States Patent
`Cantiani et at
`
`54 SUPPLEMENTATION OF CELLULOSE
`NANOFIBRILS WITH
`CARBOXYCELLULOSE WITH LOW
`DEGREE OF SUBSTITUTION
`
`75 Inventors Robert Cantiani Lyons Glues
`Guerin Eaubonne AlaIn Senechal
`Charenton
`Isabelie Vincent Evreux
`Joel Benchmol Francquevile all of
`FR
`
`73 Assignee Rhodia Chimie Boulogne Bilancnurt
`Cedex FR
`
`Notice
`
`Subject
`
`to any disclaimer the term of this
`is extended or adjusted under 35
`patent
`U.S.C 154b by
`
`days
`
`21 App No
`22 PCT Filed
`86 PCT No
`
`09/214765
`
`Jul II 1997
`
`PCT/FR97/01290
`
`371 Date
`
`May
`
`1999
`
`102e Date May
`1999
`87 PCT Pub No W098/02486
`PCI Pub Date Jan 22 1998
`
`30
`
`Jul 15 1996
`Sep 27 1996
`51 hit Cl.7
`52 U.S Ci
`
`Foreign Application Priority Data
`FR
`FR
`
`96 09061
`
`96 11986
`
`CO8L 1/02 CO9D 101/02
`106731 106/805
`106/162.8
`514781
`426/658
`
`

`

`US 6231657 Bi
`
`SUPPLEMENTATION OF CELLULOSE
`NANOFIBRILS WITH
`CARBOXYCELLULOSE WITH LOW
`DEGREE OF SUBSTITUTION
`
`371 of PCTIFR97/01290
`
`filed Jul
`
`This application is
`11 1997
`The present invention relates to compositions comprising
`amorphous cellulose nanofibrils carboxycellu
`essentially
`lose as additive and optionally co-additives
`as well as to
`process for their preparation
`The invention
`relates to the suspensions obtained from
`such compositions
`Cellulose microfibrils and nanofibrils are well-known
`compounds which are used
`as additives for modifying the
`texture of media into which they are introduced
`In the case
`of fluid media they modify their viscosity or even
`rhcnlngical profile
`However
`there is
`problem with cellulose microfibrils
`and nanofibrils which is that they are obtained in the form
`of an aqueous suspension whose solids content
`is relatively
`to about 5% by weight approximately The
`low from about
`form is thus not
`development of these products in such
`in terms of
`economically viable either
`for example It has thus been
`considered
`transportation
`naturally to present them in dry form Unfnrtunately when
`the cellulose microfibril or nanofibril suspensions are dried
`between the fibrils
`very strung hydrugen bnnds are created
`which make it necessary to use very high-shear means to
`fibrils when it
`redisperse these
`them
`
`is possible to resuspend
`
`their
`
`storage or
`
`been made to propose solutions
`Attempts
`have
`to the
`problem of drying cellulose micrnfibrils Thus additives
`have been introduced during the preparation of micrnfibril
`the time of the homog
`suspensions and more particularly at
`enization
`
`For example U.S Pat No 4481076 proposes drying
`the cellulose microfibrils obtained from wood pulp in the
`favour
`presence of additive The contents which are most
`good
`able for good redispersinn after drying and thus for
`viscosity level of the suspension are from abnut 50 to about
`100% by weight
`relative tu the dry microfibrils As may be
`observed
`the amounts of additives
`introduced
`are very
`these methods are nut entirely satisfactury
`large Mureuver
`is possible in principle to redisperse these
`even though it
`dried microfibrils since the means used for the redispersion
`are still
`
`very high-shear
`
`International patent application WO 95/02966
`describes
`the supplementation of microcrystalline cellulose with xan
`than gum or carbnxymethylcellulose with contents of less
`than 33% by weight
`relative to the weight of microcrystal
`line cellulose However extremely high-shear conditions are
`
`in the fond sector
`
`used tu suspend the dried cellulose since they are carried out
`under
`the standard cunditions
`formulations
`for stirring
`The dried
`intended for appticatinns
`micrnfibrils can thus not be considered as easily redispers
`ible
`The teaching provided by the prior art
`regarding the
`redispersion of microcrystalline cellulose microfibrils and
`those obtained from wood pulp cannot
`be
`in particular
`transposed to cellulose nanofibrils obtained from cells with
`primary walls
`Firstly the cellulose microfibrils obtained from wood are
`derived from secondary walls This means that they have
`greater than 70% degree of crystallinity During the step of
`the microfibrils obtained from wood
`homogenization of
`rather than observing
`disentangling of the fibres as is the
`
`are
`
`of
`
`the microfibrils and
`
`It
`
`in
`
`of filaments
`
`case during the step of homogenization
`of
`the cellulose
`obtained from primary walls these fibrils
`nannfibrils
`found to break Consequently
`the
`cellulose microfibrils
`obtained from secondary walls do not have the characters
`tics of amorphous fibrils but rather have the characteristics
`of microcrystalline micrnflbrils
`Moreover
`the morphnlngies
`nanofibriis are different In point of fact the microcrystalline
`microfibriis for example obtained from cellulose with sec
`10 ondary walls such as wood pulp are conventionally
`in the
`form of aggregates from few tens of nanometers to
`few
`micrometers consisting of elementary fibrils which cannot
`be disentangled during the homogenization step As regards
`the cellulose nannfibrils
`obtained from cells with primary
`few nanom
`diameter of not more than
`15 walls they have
`eters and have the appearance
`the difficulty
`is relatively well established that
`is associ
`redispersing cellulose microfibrils or nanofibrils
`bonds
`ated with the existence of numerous
`hydrogen
`during drying Now
`20 between the fibrils which are created
`the number of hydrogen bonds per weight unit of cellulose
`of
`the said
`associated with the morphology
`is directly
`microfibrils or nanofibrils and more specifically propor
`tional
`the specific
`the greater
`their specific
`surface
`to
`25 surface the larger the number of hydrogen bonds per weight
`unit of cellulose Given the particular morphology of the
`cellulose nanofibrils obtained from cells with primary walls
`the specific surface of these nannfibrils is much higher than
`person skilled in the art would thus
`that of the microfibriis
`in redis
`to encounter greater difficolties
`logically expect
`persing cellulose nanofibrils
`Thus given the state of the art presented above it could
`larger amounts of additive than those used
`be envisaged that
`for the microfibrils would be necessary
`in order to obtain
`35 good redispersion of the dried nanofibrils
`has shown against all
`However
`invention
`the present
`low amounts of additive
`are
`that relatively
`expectations
`to allow good redispersion of the dried nanofibrils
`and without
`it being necessary to use extremely high-shear
`In addition it has been found surprisingly that
`amounts of the order of those recommended in the prior art
`have
`drawbacks
`considerable
`the
`as regards conserving
`Theological properties of the nanofibrils
`This arises from the difference in behaviour between the
`for example the cellulose
`45 crystalline microfibrils
`from secondary walls and
`microfibrils
`obtained
`the
`nanofibrils obtained from cells with primary walls
`The reason for this is that
`the non-supplemented micro
`crystalline micrnfibrils are not dispersible
`in aqueous
`so medium they separate out by settling as soon as the stirring
`is stopped even when very high-shear stirring means are
`used Furthermore they do not give shear-thinning Theo
`
`30
`
`sufficient
`
`40 conditions
`
`logical properties
`On the other hand the nannfibrils obtained from primary
`nature which
`55 walls
`are of
`in aqueous
`is dispersible
`medium In additinn they give
`quite specific Theological
`profile of shear thinning type to the medium into which
`they are introduced
`Now in general drying adversely affects not only the
`and their
`capacity for redispersion of the dried nanofibrils
`profile Thus large
`viscosity but also
`rhenlogical
`amounts of additives of the type usually used to redisperse
`microcrystalline microfibrils such as those obtained from
`wood i.e as much additive as microfibrils do not give good
`results as regards the shear-thinning Theological profile of
`the cellulose nanofibrils obtained from primary walls the
`profile becomes more Newtonian
`i.e less shear-thinning
`
`60
`
`65
`
`their
`
`

`

`US 6231657 B1
`
`simple and effec
`
`invention
`
`equal
`
`co-additive
`
`of drying essen
`As may be observed the consequences
`tially amorphous cellulose nanofibrils in terms of the redis
`persion of
`these
`and
`fibrils
`their Theological
`properties
`viscosity at low and high shear
`rheological profite cannot
`satisfactory manner based on the knowledge
`be solved in
`from the supplementation
`obtained
`of microcrystalline
`microfibrils for example of microfibrils obtained from cells
`with secondary walls
`The present
`invention thus provides
`tive solution to these problems
`These
`aims and others
`are achieved by the present
`composition com
`first subject of which is
`cellulose nanofibrils car
`amorphous
`prising essentially
`degree of substitution of less than or
`boxycellulose with
`least one
`to 0.95 as additive and optionally at
`and
`co-additive
`the content
`of additive
`of optional
`to 30% by weight
`.being less than or equal
`and
`relative to the weight of nanofibrils and of additive
`optional co-additive
`Another subject of the present
`invention
`consists of
`composition in which cellulose
`process for preparing
`nanofibrils are prepared from cellulosic pulp by carrying out
`least one
`least one extraction optionally followed by at
`at
`after which
`step of bleaching
`the pulp thus treated
`homogenization
`resulting pulp is separated out and
`step is
`least one cycle the characteristic of
`carried out
`the following steps are carried out
`process being that
`at least some of the additive and optionally co-additives
`are added
`to the nanofibril suspension which
`has
`optionally undergone
`least one
`homogenization
`
`the
`
`the
`
`in at
`
`at
`
`oranges and grapefruit and most
`examples of parenchyma
`
`fruit
`
`and vegetables are
`
`the nanofibrils
`
`forming part of the composi
`Moreover
`tions according to the invention are according to
`particu
`the surface with
`
`alone or as
`
`advantageous variant charged at
`larly
`carboxylic acids and with acidic polysaccharides
`mixture
`The term carboxylic acids is intended to refer to simple
`acids as well as salts thereof These
`acids
`are
`carboxylic
`10 preferably chosen from uronic acids More particularly the
`said uronic acids are more particularly galacturonic acid and
`acid
`
`20
`
`According
`the present
`
`glucuronic
`mention may be made of
`As acidic pnlysaccharides
`pectins which are more particularly polygalacturonic
`acids
`is These acidic pnlysaccharides
`can be present as mixture
`with hemicellulnses
`have
`Tbe cellulose nanofibrils
`also
`cross-section of
`and about 10 nm More particularly the
`between about
`nm
`nanofibril cross-section is betwecn about
`and about
`particularly advantageous embodiment of
`to
`invention the nannfibrils forming part of the
`according to the invention
`are obtained by
`compositions
`using the treatment which will be described below
`More particularly this treatment
`is carried out on the pulp
`25 of vegetables with primary walls such as for example
`preliminary step of
`beetront pulp after
`it has undergone
`extraction of the sucrose according to the methods known
`in the art
`Thus the process comprises the following steps
`first acidic or basic extraction after which
`first solid
`
`30
`
`residue is recovered
`optionally second extraction carried out under allca
`line conditions of the first solid residue after which
`second solid residue is recovered
`washing of the first or second
`optionally bleaching of the washed residue
`
`solid residue
`
`35
`
`40
`
`dilution of the third solid residue obtained after step
`solids content of between
`and
`so as to obtain
`10% by weight
`homogenization of the dilute suspension
`the term pulp is intended to refer
`to wet
`In step
`dehydrated pulp stored by ensilage or partially depectinized
`The extraction
`in acidic
`carried out
`can be
`step
`in basic medium
`45 medium or
`For an acidic extraction the pulp is suspended in an
`few minutes so as to homogenize the
`aqueous solution for
`pH of between
`acidified suspension at
`and
`preferably
`between 1.5 and 2.5
`
`so
`
`For
`
`This operation is carried nut with concentrated solution
`of an acid such as hydrochloric
`acid or sulphuric acid
`This step may be advantageous for removing the calcium
`oxalate crystals which may be present
`in the pulp and
`which on account of their highly abrasive nature can cause
`in the homogenization step
`55 difficulties
`basic extraction the pulp is added
`to an alkaline
`base for example sodium hydroxide or potas
`solution of
`of less than 9% by
`sium hydroxide with
`concentration
`than 6% by weight
`weight more particularly
`less
`60 Preferably the concentration of the base is between
`and
`2% by weight
`small amount of
`water-soluble antioxidant such as
`sodium sulphite Na2503 may be added in order to limit
`oxidation
`reactions of the cellulose
`
`the
`
`is
`
`to
`
`rheological
`
`propose
`nanofibrils
`
`after
`
`to
`
`cycle
`step of drying the suspension thus supplemented
`carried out
`relates to
`third subject of the invention
`suspension
`comprising cellulose nanofibrils which is obtained by redis
`persing the composition according to the invention
`The present invention makes it possible simultaneously
`for drying essentially amorphous
`process
`as well as compo
`in the presence of additives
`sitions which are dried such
`that
`are
`they
`readily
`the same time retaining the specific
`redispersible while at
`rheological properties of the initial
`non-dried suspensions
`Thus the suspensions according to the invention obtained
`redispersing the compositions have
`good level of
`low shear gradient as well as
`viscosity at
`profile of shear-thinning type
`In addition the means used to redispersc the dried com
`less
`positions according to the invention
`are considerably
`than those usually used to redisperse dried
`shearing
`microfibrils obtained from wood or
`from other secondary
`walls
`Other characteristics and advantages of the present inven
`tion will emerge more clearly on reading the description and
`the examples which follow
`As has been mentioned previously the subject of the
`present invention is the supplementation of essentially amor
`phrms cellulose nanofibrils
`The term essentially amorphous is intended to refer to
`nanofibrils whose degree of crystallinity is less than or equal
`to 50% According
`variant of
`the present
`specific
`invention the degree of crystallinity is between 15% and
`50% Preferably the degree of crystallinity is less than 50%
`The cellulose nanofibrils treated according to the present
`invention are obtained from cells preferably consisting of at
`least about 80% primary walls Preferably the amount of
`least 85% by weight
`primary walls is at
`Such characteristics
`are present
`in particular
`mal cells Sugar beet pulp citrus
`
`fruits such
`
`in parenchy
`as lemons
`
`65
`
`carried out
`temperature of
`is generally
`Step
`at
`and 100
`between about 600
`preferably between about
`70
`and about 95
`
`

`

`US 6231657 Bi
`
`The duration of step
`hours
`
`is between about
`
`hour and about
`
`During step
`partial hydrolysis takes place with release
`and solubilization of most of the pectins and hemicelluloses
`the same time retaining the molecular mass of the
`while at
`
`cettulose
`
`from the
`The solid residue is recovered
`suspension
`out known methods
`obtained from step
`by carrying
`Thus it
`to separate the solid residue
`by
`is possibte
`centrifugation by filtration under vacuum or under pressure
`with filter
`filter presses for example or else by
`gauzes or
`
`evaporation
`The first solid residue obtained is optionally
`subjected to
`second
`extraction step carried out under alkaline condi
`
`tions
`
`is carried out when the
`second extraction step step
`step has been carried out under acidic conditions
`the
`If
`been
`out under alkaline
`extraction has
`carried
`
`first
`
`first
`
`conditions the second
`
`step is optional
`According to the process this second extraction is carried
`base preferably chosen from sodium hydroxide
`out with
`and potassium hydroxide whose concentration is less than
`about 9% by weight preferably between about 1% and about
`6% by weight
`The duration of the alkaline extraction step is between
`and about
`hours It
`about
`to about
`hours
`
`is preferably equal
`
`if
`
`it
`
`is carried out
`
`second
`
`is
`
`hour and
`
`hour and about
`
`in
`
`to
`
`homogenization
`
`After this second extraction
`solid residue is recovered
`the residue derived from step
`In step
`or
`washed thoroughly with water in order to recover the residue
`of cellulosic material
`The cellulosic material
`from step
`is then optionally
`bleached in step
`according to the standard methods For
`treatment with sodium chlorate with sodium
`example
`proportion of
`or with hydrogen peroxide in
`hypochlorite
`520% relative to the amount of solids treated can be carried
`out
`Different concentrations of bleaching agent can be used
`and about 80
`at temperatures of between about 18
`and about 70
`preferably between about 50
`The duration of this step
`is between about
`hours preferably between about
`about
`hours
`cellulosic material containing between 85 and 95% by
`weight of cellulose is thus obtained
`After this bleaching step it may be preferable to wash the
`cellulose thoroughly with water
`The
`resulting suspension which has optionally been
`bleached is then rediluted in water
`proportion of
`10% solids step
`before undergoing
`step step
`least one cycle
`comprising at
`invention
`According to
`variant
`of
`the
`the
`nanofibrils are supplemented before undergoing the homog
`enization step
`According
`second
`variant of
`cellulose
`nanofibrils are supplemented
`undergone at
`least one homogenization cycle
`The homogenization
`mixing or
`step corresponds
`operation or any operation of high mechanical
`blending
`followed by one or more passages of the cell suspen
`sion through an orifice of small diameter
`subjecting the
`least 20 mPa and to
`pressure drop of at
`suspension to
`high-speed shear action followed by
`high-speed decelera
`tion impact
`The mixing or blending is carried nut
`passages
`through the mixer or blender fur
`
`first
`
`to
`
`the
`
`invention the
`they have
`
`after
`
`shear
`
`to
`
`for example by
`
`period ranging
`
`from few minutes to about an hour in machine such as
`Waring Blendor
`fitted with
`four-blade impeller or
`pan
`type of blender such as
`mill mixer or any other
`colloidal
`mill
`The actual
`homogenization will advantageously be car
`ried out in homogenizer such as Manton Gaulin in which
`the suspension is subjected to
`shear action at high speed
`narrow passage and against an impact
`and high pressure in
`ring Mention may also be made of the Micro Fluidizer
`which is
`homogenizer mainly consisting of
`compressed-
`air motor which creates
`very high pressures an interaction
`chamber in which the homogenization operation takes place
`impacts and cavitations
`and
`low-
`elongational shear
`pressure chamber which
`allows depressurization
`dispersion
`The suspension is introduced into the homogenizer pref
`temperature of between 40 and
`erably after preheating to
`preferably between 85 and 95
`120
`The temperature of the homogenization operation is main
`tained between 95 and 120
`preferably above 100
`The suspension is subjected to pressures of between 20
`and 100 mPa and preferably above 50 mPa in the homog
`enizer
`
`the
`
`of
`
`20
`
`of the cellulosic
`
`until
`
`be
`
`Homogenization
`suspension is obtained
`and 20
`number of passages which can range between
`by
`between
`and
`25 preferably
`stable suspension is
`obtained
`The homogenization
`can advantageously
`operation
`followed by
`for example
`high mechanical shear operation
`in machine such as the Sylverson Ultra Turrax
`It should be noted that this process has been described in
`European patent application El 726356
`filed on Jun
`1996 and reference may thus be made thereto if necessary
`Example 20 of that
`gives method for
`in particular
`suspension of essentially amorphous cellulose
`preparing
`
`30
`
`text
`
`35 nanofibriis
`The additives will now be described
`The first
`according to the
`additive in the composition
`in salt form or in acid
`invention consists of carboxycellulose
`form
`
`40
`
`The cellulose used
`
`45
`
`50
`
`According
`
`as additive is more particularly car
`polymer consisting of
`boxymethyleellulose Cellulose-is
`glucose monomer units The carbuxyl group is introduced in
`manner which is known per se by reacting chloroacetic
`acid with cellulose
`The degree of substitution corresponds to the number of
`The maximum
`carboxymethyl
`groups per glucose unit
`theoretical degree
`is
`to the invention the degree of substitution of
`to 0.95
`is less than or equal
`carboxymethylcellulose
`The
`degree of polymerization of
`the carboxycellulose
`used as nanofibril additive in accordance with the present
`wide range Thus earboxymeth
`invention varies within
`yleelluloses of high masses high degree of polymerization
`low masses
`low degree
`of
`high viscosity or of
`55 polymerization low viscosity are suitable
`In the first category mention may be made of eellulnses
`whose viscosity is between about 9000 mPa.s measured in
`1% solution Bronkfield 30 rpm and
`250
`an aqueous
`mpa.s measured in an aqueous 6% solution Brookfield 60
`60 rpm
`category mention may be made of cellu
`In the second
`loses whose viscosity is between about 250 mpa.s measured
`6% solution Brookfield 60 rpm and 10
`in an aqueous
`mpa.s measured in an aqueous 6% solution Brookfield 60
`65 rpm
`In the ease of
`is less than or equal
`
`content
`
`the first
`
`the earboxyeellulose
`category
`to 30% by weight
`
`

`

`US 6231657 B1
`
`to
`
`second
`
`as co-additive
`
`at
`
`According
`specific variant of the invention
`the compositions comprise carboxycellulose
`as additive and
`least one compound chosen from cationic
`and amphoteric surfactants
`In the case of this second variant the co-additive content
`and 10% by weight
`is between
`relative to the weight of
`naoofibrils
`and of additive and of co-additive
`In each of the two variants the content of carboxycellu
`to 30% by weight
`relative
`lose additive is less than or equal
`of nanofibrils and
`of additive
`
`to
`
`and of
`
`can
`
`also
`
`In the case of the second
`the carboxycellulose
`category
`is between 10 and 30% by weight
`content
`The
`invention
`according to the
`composition
`chosen from
`comprise at least one co-additive
`saccharide monomers or oligomers
`of formula R1R2NCOA in which formula
`compounds
`and R2 which may be identical or different repre
`C1C10 preferably C1C5 alkyl
`seot hydrogen or
`represents hydrogen
`C1-Cl3 preferably
`radical
`the group R1 R2N
`C1C5 alkyl radical or alternatively
`with R1 and R2 which may be identical or different
`representing hydrogen or C1C10 preferably C1C5
`alkyl radical
`
`10
`
`it being possible for
`cationic or amphoteric
`surfactaots
`to be used alone or as mixture
`these co-additives
`Among the saccharide monomers or oligomers mention
`may be made most particularly and without
`intending to be
`limiting of sorbitol sucrose and fructose
`As regards the compounds of the type RR2NCOA it
`is
`two amide func
`preferred to use compounds comprising
`tions Preferably urea is used as co-additive
`Among the cationic surfactants mention may be made of
`ammonium derivatives
`such as for
`cationic
`quatemary
`imidazolioe derivatives
`example catiooic
`alkyltrimethylammonium dialkyldimethylammonium
`alkyldimethylbenzylammonium or atkyldimethylethylam
`mooium halides and Quat esters
`As examples of suitable cationic
`compounds meotioo
`from
`may be made of the products sold by Rbôoe-Pouleoc
`the Rhodaquat
`is also possible to use synthetic
`raogc
`the CTFA generic name of
`cationic polymers known under
`Polyquaternium for example the polymers Mirapol A15
`or Mirapol 550a from the company Rbone-Pouleoc
`The surfactants
`forming part of the formulatioo according
`to the invention can also be chosen
`from ampboteric sur
`factants For example mention may be made without
`be limiting of alkylpolyamine amphoteric
`intending
`derivatives alkylbetaioes alkyldimetbylbetaioes
`alkylamidopropylbetaines
`lm do prop
`dime thy lb eta in
`1k
`alkyltrimethylsulpbobetaioes imidazoline derivatives
`as alkyl amphoacetates
`alkyl amphodiacetates
`alkyl
`alkyl ampbodipropionates
`amphopropionates
`or alkylamidopropythydroxysultaines and
`alkylsultaines-
`the condensation
`acids
`products of
`and of protein
`fatty
`hydrnlysates it being possible for these compounds to be
`used alone or as mixture
`surfactants Mirapon Excel Mirataine CBS
`The
`Mirataine CB Mirataine H2CFIA Ampholac 7T/X
`Ampbolac 7C/X the Miranol
`range Amphionic SFB 50
`and Amphionic XL may in particular
`be suitable
`for
`carrying out
`the present invention
`according to the invention com
`When the compositions
`prise one or more of the abovemeotioned co-additives
`is less than 30% by weight
`content
`relative to the weight of
`nanoflhrils and of additive and of co-additive
`Needless to
`say the content of additive and of co-additives is such that
`to 30% relative to the weight of
`is less than or equal
`nanofibrils of additive and of co-additives
`first specific variant of the invention the
`According
`to
`as additive as well
`compositions
`comprise carboxycellulose
`from saccharide mono
`least one co-additive
`chosen
`as at
`formula R1R2N
`mers and oligomers or compounds of
`COA
`In the case of this first variant
`and 25% by weight
`between
`relative to the weight of
`naoofibrils and of additive and of co-additive
`
`It
`
`to
`
`it
`
`15
`
`20
`
`25
`
`30
`
`35
`
`40
`
`45
`
`55
`
`60
`
`such
`
`their
`
`the co-additive content
`
`is
`
`65
`
`the weight
`co-additive
`In the case of redispersioo additives sucb as carboxycel
`low degree of substitution
`lulose with
`degree of substi
`to 0.95 the higher
`less than or equal
`its
`the more it
`lowers the shear-thinning nature
`the cellulose nanofibrils by modifying their
`of
`state of
`dispersion in tbe water Thus for additive concentrations of
`than 30% by weight
`relative
`to the weight of
`and of additive and of co-additive although the
`nanofibrils
`nanofibrils are
`redispersible tbeir Theological
`becomes more Newtonian
`i.e less shear-thinning
`embodiment of
`particularly advantageous
`comprising
`invention
`consists of compositions
`present
`naoofibrils with
`content of additive and of co-additive of
`less than or equal to 30% by weight
`relative to the weight of
`and of additive aod of co-additive Preferably the
`naoofibrils
`is between 5% and 30% relative to the same
`said content
`the usc of such
`refereoce It
`should
`be noted
`that
`co-additives described above makes it possible in combi
`nation witb earboxymethyleellulose to reinforce the shear-
`thinning profile of the cellulose nanofibrils after redisper
`sion
`
`tution of
`
`concentration
`
`greater
`
`first
`
`profile
`
`the
`
`is at
`
`according to the
`is usually between
`
`in
`
`in this
`
`according to the invention
`In addition the compositions
`least 40% by weight More
`have
`solids content of at
`least 60% by weight and
`particularly the solids content
`least 70% by weight
`is preferably at
`The particle sixe of
`the composition
`invention can vary within wide range It
`Aim aod
`few millimeters
`The process for preparing the compositioos will now be
`described in greater detail
`The process according to the invention consists firstly
`preparing the cellulose oaooflbrils
`from appropriate cello
`losic pulp by carrying out
`followed
`hydrolysis optiooally
`least one step of bleaching of the pulp thus treated
`by at
`Everything which has beeo mentioned
`previously
`remains valid and will not be repeated here
`respect
`The process
`for preparing the compositions
`according to
`least some
`first step in adding at
`the invention consists in
`of the additive and optionally co-additives to the nanofibril
`least one
`suspension which has optionally undergone at
`bomngeoization
`cycle Next
`step
`step of
`second
`in
`drying the suspension thus supplemented is carried out
`Accnrding
`first advantageous variant of the present
`to
`least some of the additive and
`invention the addition of at
`optionally co-additives is carried nut after
`
`the homogeni
`
`zation step
`One particularly suitable embodiment of the invention
`least some of the additive and option
`consists in adding at
`ally co-additives to the suspnsinn afier the homogeniza
`this suspension has undergone at
`least one
`
`tion step afier
`
`concentration
`step
`cen
`The concentration steps take place by filtration
`from the
`or evaporation of some of the water
`trifugatino
`is possible for example to use filters under
`suspension It
`vacuum or under pressure spraying towers ovens or micro
`wave ovens
`
`

`

`It
`
`is thus possible to carry out
`in an alcohol such
`as ethanol
`
`similar alcohol
`
`US 6231657 Bi
`
`be
`
`10
`weight of the solid obtained More particularly the weight of
`water maintained is between 10 and 30% by weight Such an
`the thresh
`implementation makes it possible not
`to exceed
`old beyond which redispersion of the nanofibrils may no
`longer be complete
`The drying advantageously takes place in air although it
`may be envisaged tu carry it out under an inert gas such as
`nitrogen
`
`It should also be noted that
`is preferred to carry out the
`drying in an atmosphere whose degree
`of humidity is
`controlled so as to be able to maintain the desired moisture
`
`it
`
`in the composition
`content
`The drying temperature should limit
`any degradation of
`of the
`the carboxylic
`acids of the acidic polysaccharides
`and/or of the additives and cu-additives
`hemicelluloses
`and 80
`IS more particularly between 30
`between 30
`and 60
`it would not constitute
`It should be noted that
`departure
`from the context of the present
`invention
`to carry out
`drying operation in several steps some of which would use
`the means indicated above for the concentration step
`After the drying step the composition obtained can be
`blended
`
`It
`
`is
`
`preferably
`
`to
`
`precipitation for example
`or any other
`isopropanol
`process of separation by
`to carry out
`hygroscopic solution
`freezing-thawing by dialysis against
`in which the size of the molecules is greater than the size of
`the pores in the membrane used
`These methods are cited merely as guides and cannot
`considered as an exhaustive list
`to this embodiment the concentration opera
`According
`solids content of about 35% ie
`tion can be carried out until
`is obtained More particularly the solids content
`by weight
`and 25% by weight
`is between
`the additive and
`The
`intruduction
`of
`optionally
`co-additives is carried out in manner which is known per
`se i.e by any means which-allows
`homogeneous introduc-
`powder
`tion of
`suspension or
`suspension
`solution
`which tends to have the consistency of
`paste For example
`extruders and mixers
`mention may be made of blenders
`This operation can be carried out over wide temperature
`range more particularly between room temperature and 80 20
`It may be advantageous
`the introduction
`to carry out
`at the
`temperature at which the concentration took place It should
`also be noted that temperatures from about 50
`to about
`80
`can also facilitate the addition of the additive by
`decreasing its viscosity for example
`second embodiment of the process consists in adding at
`least some of the additive and optionally co-additives to
`the homogenization
`the suspensioo after
`step before this
`suspeosioo has undergone at least one concentration step
`lo this latter case the concentration steps which take
`and optionally of
`the addttioo of additive
`place atter
`in the same way as indicated
`
`25
`
`30
`
`co-additive
`
`are carried out
`
`above
`
`If this first variant
`
`preferred embodiment
`is carried out
`of the invention is to carry out the supplementation after the 35
`suspension has undergone one or more concentration steps
`According to
`second advantageous variant of the present
`least some of the additive and
`invention the addition of at
`
`If such
`possibility is selected the particle size of the
`pm and
`is generally between
`few millimeters
`powder
`preferably between 30 nm and
`few millimeters Such
`particle size makes it possible to have good redispersion
`without having too maoy handling problems
`Another
`invention consists of
`subject of the present
`suspension of cellulose naoofibriis which
`is obtained by
`redispersioo of the supplemented composition according to
`in water or any other medium
`the invention
`Besides the fact that it can be obtained by redispersion of
`the composition according to the invention the suspension
`the invention
`has
`profile of
`
`Theological
`
`least
`
`invention
`
`is also
`
`the use of
`
`according t