1813_0_cmcchemistry.pdf

7/30/2019 1813_0_cmcchemistry.pdf

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www.cpkelco.com

Basic chemistryBasic chemistry

of CMCof CMC


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Product lineProduct line

Finnfix Industrial/technical CMC

Cekol Food/Pharma CMC

Cellufix Easy dispersible industrial CMC

Cellcosan Industrial CMC with high DS

Nymcel Cross linked pharmaceutical CMC

Celflow Modified CMC


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Cellulose

(wood/cotton)OH

CH2OH

OH

OH

CH2OH

OH

OH

CH2OH

OH

Sodium Hydroxide Monochloro acetic acid

+ sodium chloride and sodium glycolate

CMC: Carboxymethyl CelluloseCMC: Carboxymethyl Cellulose

O CH2COO-

CH2O CH2COO-

O CH2COO-

O CH2COO-

CH2O CH2COO-

OH

OH

CH2O CH2COO-

OHCMC

CH2O

Cl- CH2COO-


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Cellulose ether produced by chemical modification of cellulose

CMC= Sodium CMC, Cellulose gum, Sodium Carmellose

Anionic poly electrolyte

White to off-white fibrous powder

Cold water soluble

What is CMCWhat is CMC


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Chemical reaction

Purification

Solvent recovery and drying

Mechanical treatment

Packing

Cellulose, NaOH, MCA

and inert solvent (alcohol)

Washing with alcohol/water

Grinding, sieving,

densification etc.

Production of CMCProduction of CMC


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Technical

55 - 75% Paper, Detergents, Oil drilling(remaining is salt)

Purified

>98.0% Paper, Textile, Paint

>99.5% Food, Pharma & Personal Care

CMC: TypesCMC: Types


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Molecular weight / viscosity Degree of substitution Molecular design Cellulose source

Powder / granules Bulk density Surface modification

Reaction time Reaction temperature

Chemical parameters

Physical parameters

CMC: ParametersCMC: Parameters

Rheology Water binding capacity

Stability

Interaction with other components Adhesion Dissolution speed Processing

Dispersibility

..Process parameters


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Increasing molecular weight:

higher viscosity less stable more pseudoplasticity

Increasing DS:

more stability less thixotropy more clarity less interaction with a.o. glycerol

more water interaction

-In theory, maximum DS is 3.0 and minimum is 0.0 (=cellulose)

-Commercially between 0.40-1.50, typically between 0.60-0.90

1

10

100

1.000

10.000

1 10 100 1.000 10.000

Shear rate

Viscosity

CEKOL 700

CEKOL 30

CEKOL 30.000

Influence of chemical parametersInfluence of chemical parameters


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Rheology of Xanthan gum & CMCRheology of Xanthan gum & CMC

10

100

1000

10000

100000

1000000

0.001 0.01 0.1 1 10 100 1000 10000

Shear Rate (s-1)

Viscosity

(mPa.s

)

0.5% KELZAN

0.5% Cekol 100000

The low shear viscosity of KELZANis 10x higher than Cekol 100000


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uniform

block wise

(both DS = 0,5)

1,000

10,000

100,000

0 1 2 3 4 5 6

Time [days]

Viscosity

Uniform

Block Thixotropicity

Distribution of SubstitutionDistribution of Substitution


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100

1000

10.000

4,0 7,0 9,0 12,0pH

Viscosity

CEKOL 300

CEKOL 30.000

pH < 3-4: gelly particles (acidic CMC)

viscosity drop and precipitation in time

pH > 12: viscosity drop in time

Effect of pHEffect of pH


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0

200

600

1000

1400

1800

2200

10 min. 80C 1 min. 120C 60 min. 120C 60 min. 120C(high DS)

Viscos

ity,mPas

Initial viscosity

Viscosity afterheating andcooling

1% CEKOL 30.000

*

Heat treatment 1Heat treatment 1


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Viscosity

Heating Cooling

Viscosity is reversible when heating and cooling(to a certain extend)

Heat treatment 2Heat treatment 2


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Particle size 1Particle size 1

Every CMC factory has its own fingerprint with regard to the particle

size distribution. It is impossible to exactly copy a competitiveproduct (works both ways)

Even within the same production line, the particle size distribution

depends on viscosity, DS and CMC content of a grade.

Cekol 30.000 from Sweden is somewhat different from:

-Cekol 30.000 from Holland

-Cekol 30 from Sweden

It is is very difficult to give general specifications on particle size


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Particle size 2Particle size 2

Smaller particles dissolve faster, but good mixing is required!!Granular particle disperse very easy but it takes longer to dissolve

Fine powder (P-grade) or granules (G-grade) are produced by

either sieving or grinding.

Also coated CMC grades available for improved dissolution

behaviour


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Particle size CP Kelco CMCParticle size CP Kelco CMC

Finland produces industrial grades and its standard particle is

bigger than Sweden and Holland as this is generally desired by the

industry:

P-grade from >0.075 mm

-Sweden max 20%

-Holland max 20%

-Finland max 30%

These typical values are workable for most customers. When the

volume allows it, it is possible to make customer specifications on

different sieves.


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Basic properties of CMCBasic properties of CMC

Viscosity: Newtonian to pseudoplastic

Thickening properties

Stabilising

Water retention

Good film forming (Transparent films, tablet coating)

Anti re-deposition (Detergents)

Tablet disintegrant (Control tablet dissolution)

Binding (Welding rods, Car batteries)

1813_0_cmcchemistry.pdf

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