PIGMENT

Pigment

• What is pigment

• A pigment is a material that changes the color of reflected or transmitted light as the result of wavelength-selective absorption. This physical process differs from fluorescence, phosphorescence, and other forms of luminescence, in which a material emits light

• Many materials selectively absorb certain wavelengths of light. Materials that humans have chosen and developed for use as pigments usually have special properties that make them ideal for coloring other materials. A pigment must have a high tinting strength relative to the materials it colors. It must be stable in solid form at ambient temperatures.

PIGMENTis a particulate solid dispersed into a medium

without solution or significant interaction

Differences between Pigments and Dyes

Pigments are dispersions in medium but dyes are solutions

Pigments posses particulate properties but dyes do not

Pigments are far more durable and resistant to fading than dye

Differences between Pigments and Dyes

Pigment

Dye

Applications of Pigments

1 Inks : water and solvent based2 Paints : water and solvent based3 Plastics : all types including EVA4 Rubber 5 Glass6 Ceramic7 Textile8 Cement Products9 Cosmetics

Required Properties of Pigments

Colour Weather Stability

Colour Strength Opacity

Heat Resistant: IK Insolubility

Light Fastness: sun light, xenon

Solvent Fastnesss

Color Strength

Full-Tinting Strength

Two Roll Mill

Two Roll Mill

Solvent Fastness

Effect of particle size of the pigment

1 Tinting strength2 Gloss3 Viscosity4 Weatherfastness

Forms of Pigments

Solid Minimum 95% Pigment content

Presscake Maximum 40 % Pigment Content

Chip, masterbatch Usually 20-25 % Pigment Content

BASIC / PRIMARY COLOURS (2nd & 3ry ?)

Organic Pigments vs Inorganic Pigments

Particular Inorganic Pigment Organic pigment

Color Dull Bright

Color strength Low High

Opacity Opaque Transparent

Light Fastness Good Vary from poor to good

Heat Fastness Good Vary from poor to good

Chemical Fastness Poor Very Good

Solubility Insoluble in sovents Have little degree of solubility

Degree of safety May be unsafe Usually safe

Classification of Organic Pigments

• Azo Pigments• Non-Azo Pigments = Polycyclic Pigments

Azo Pigments Azo Pigments have the azo group (-N = N-) There are 2 stages for the synthesis of azo pigments: - Diazonium salt formation - Coupling reaction

Monoazo Yellow and Orange Pigments

1. They are obtained by coupling a diazonium salt with acetoacetic arylides to give greenish to medium Yellow Pigments

2. While coupling with 1 – arylpyrazolones-5 produces reddish orange shade

3. Their process good light fastness but poor solvent & migration resistance

4. commercial application in certain inks ( flexo & offset inks)

Monoazo yellow

Monoazo Orange

Disazo Pigments

• Disazo Pigments : 2 classes 1. The coupling of di – and tetra – substituted diaminodiphenyls with acetoacetic arylides or pyrazolones

2. The coupling of diazotization of aromatic amines with bisacetoaceticarylides

3. These pigments cover the colour range from greeny yellow to reddish yellow & orange & red

4. They have better solvent & migration fastness than mono azo pigments & are use in printing inks & plastic

The color potential of disazo pigments covers the color range from very greenish yellow and orange and red

Disazo Pigments(2 Oxygens missing)

β- Naphthol Pigments

Beta Naphthol Pigments provide colours from orange to medium red

Production by coupling reaction with beta naphthol

Solvent resistant, migration fastness & light fastness are comparable to mono azo yellow pigments

Commercial application in paints

Beta Naphthol Pigment

Naphthol AS Pigments (Naphthol Reds)

These pigments provide colour from yellowish & medium red to brown & violet

They are obtain by coupling reaction of aryl diazonium salt with aryllides of 2-hydroxy-3-naphthoic acid

Their solvent fastness & migration resistance marginal

Commercial application in printing inks & paints

Naphthol AS Pigment (2 N missing)

Azo Pigment Lake(Salt Type Pigments)

These pigments provide colours between medium red to bluish red

They are from by precipitating a monoazo compound with contain sulfo & / or carboxy groups with metal cations such as calcium, barium, magnesium, strontium or manganese.

These pigments have limited light fastness & migration resistance but good heat fastness.

Their commercial application are in printing inks, plastic & paints

Naphthol AS Pigment Lakes

Beta Naphthol Pigment Lakes

Azo Metal Complexes

Bona Pigment Lakes

Naphthalenesulfonate Pigment Lakes

Azomethine Metal Complexes

Benzimidazolone Pigments

These pigments cover the spectrum from greenish yellow to orange & medium red to maroon

There two type : the first one is obtain by coupling with 5-acetoacetylaminobenzymidazolone,the second one the coupling components is 5-2-hydroxy-3-naphthoaylamino-benzymidazolone

Pigment performance including light fastness & weather ability is excellent

Application in plastics & hybrid printing inks

Benzimidalone Pigment

Benzimidazolone Pigment

Disazo Condensation Pigments

The spectral range of these pigments covers from greenish yellow to orange & blueish red or brown

They are obtained from the condensation of two carboxylic monoazo with one aromatic diamine

They have wood solvent & migration resistance & light fastness

Application in plastic & spin dyeing

Disazo Condensation PigmentsYellow (missing R, CONHAr)

Disazo Condensation Pigments, Red(missing R, CONH2)

Isoindolinone & Isoindoline Pigments

These pigments produce greeny to reddish yellow

They show good light & weather fastness, solvent & migration resistance

Commercial application in plastic & high grade coatings

Isoindolinone

Isoindoline Pigments

Polycylic Pigments

These are pigments with condendsed aromatic or heterocyclic ring systems

They have good light, heat and weather fastness and good solvent and migration resistance

They are more expensive than azo pigments except the phthalocyanine pigments

They are use in all application ranging from water & solvent base inks, water & solvent base paints, plastic, rubber, cement & textile

Phthalocyanine Pigments

These pigments are the most produced organic pigment in the world. They cover the colour from greenish blue to reddish blue & blueish green to yellowish green

They are produce by reacting metal salt with nitrogen source compound & phthalic acid derivative

They show good solvent & migration resistance, good , light, heat, chemical & weather fastness

Commercial application cover a whole range of product

Phthalocyanine Pigment

Quinacridone Pigments

These pigments available in a reddish violet and a blueish red

Like the phthalocyanine pigments ,quinacridone are make in two stages , the preparation of crude quinacridone and the pigmentation the crude

They have outstanding light & weather fastness & solvent & migration resistance

Commercial application are for high grade coating ( automotive), for plastics & special inks

Quinacridone Pigments

Perylene and Perinone Pigments

The color of perylene is red while for perinone is orange

They provide excellent light , heat and weather fastness

Commercial application are for spin dyeing, polyolefin, special printing inks for metal decoration and poster printing and automotive paints

Perylene Pigments

Perinone

Diketopyrrolo Pyrrole (DPP) Pigments

They provide colour range from orange to blueish red

The pigment consist of two anelated five membered rings each of which contain a carbonamide in the ring

They have excellent light and weather fastness as well as good heat stability

Commercial application are for plastics and automotive finishes

Diketopyrrolo Pyrrole pigment

Thioindigo Pigments

This is reddish violet shade pigments

They show good light fastness and weather fastness

They are generally used in plastics and industrial coating such as automotive finishes

Thioindigo Pigments

Anthrapyrimidine Pigments

This class of pigment provide a greenish to medium yellow coloration

They have excellent heat & weather fastness

Commercial application are for industrial coating such as automotive metallic finishes

Anthrapyrimidine

Flavanthrone Pigments

Flavanthrone yellow .the only commercially use flavanthrone is a brilliant reddish yellow

Excellent light and weather fastness combined with good solvent and migration resistance

Commercial application for automotive finishes

Flavanthrone

Pyranthrone Pigments

Most pigments are orange but others are blueish red colour

These are derivatives of pyranthrone molecule with varying level of halogenation

They have good weather fastness

Commercial application for high grade industrial finishes.

Pyranthrone Pigments

Anthanthrone Pigments

The only commercial pigments is dibromoanthanthrone which provides shade of scarlet for metallic finishes

They have outstanding weather fastness

Commercial application are in high grade

Anthanthrone

Dioxazine Pigments

These pigments produced violet colouration and in combination with phthalocyanine blue pigment produces a very reddish shade

Dioaxazine Pigments are derived from triphenodioxazine, linear system of five anelated rings

They show extreemly light and weather fastness as well as excellent solvent and migration resistance

Commercial application include the pigmentation of plastics, printing inks, spin dyeing and coating

Dioxazine Pigments, violet 23 & 37

Triarylcarbonium Pigments

The colour covers from green,violet and victoria blue

There are two types of these pigments: salt of triphenylmethane sulfonic acid salt of heteropolyacid with tungsten, molybdenum, silicon or iron

They have poor solvent resistance and limited light fastness but have excellent colour brilliant and clarity of hue better than any other organic and /organic pigments

Commercial application is for printing inks especially are for packaging inks

Triarylcarbonium Pigments

Quinophthalone Pigments

They are mostly greenish yellow

These pigments have a polycylic structure derived from quinaldine and phthalic anhydride

They have excellent temperatures resistance

The main market for these pigments are in the plastics and coating industries

Quinophthalone

Synthesis of Pigmentsazo pigment & copper phthalocyanine

Production of CI Pigment Yellow 1, 11680

Diazotization In a vessel 912 kg of 4-methyl-2-nitroaniline is stirred over night with water.Then 3395 L of 5 mol / L HCl is added, together with some ice to lower the temperatures to 0 C. Sodium nitrite solution, 792 L of 40 wt % is then run in underneath the surface.Any excess sodium nitrite is removed by addition of 3- nitro- p-toluidine.Active charcoal is added as clarifying agent and then filtered

Dissolution the coupling componentAcetoAcetanilide, 1098kg, is strirred with water for 1 H at 25C then 510 kg of CaCO 3 and 206 kg of 33% NaOH solution is then added.

Production of CI Pigment Yellow 1, 11680

Coupling

The reaction mixture is heated to 33 C and the clarified diazonium salt solution is then run in.

After 30 minutes HCl is added to adjust the pH to 3-4.

After 20 minutes the pigment is separated by filtering through a filter press and wash with water to remove salt.

The filter cake ( press cake ) is dried at 60-65C

The yield is 2042 kg

Production of CI Pigment Red 112, 12370

Diazotization

In a steel-enamel stirred tank, 1000 kg of glacial acetic acid is heated to 65 C , and 552 kg of 2,4,5-trichloroaniline is added.

The soln is run into a mixture of 7000 L of water and 2240 L of 5 mol/L of HCl. The reaction mixture is cooled to 0C by addition of ice and repeatedly diazotizide with 370 L of 40 wt %NaN02 soln. The temp must not exceed 0 C.

After 2 h, 214 kg of CaCO3 suspended in water is added, The volume is made up to 28500L with water; active charcoal are added and the soln is filtered thro a clarifying filter.

Dissolution of the coupling component

At 30 C, 840 kg of naphthol AS/D is dissolved in 644 L of 33% of NaOH and 6000L of water ; 20 kg of active charcoal is then added and the soln is filtered. Then 168 g of Igepon T in 400 L of water is added and the mixture is cooled to 3 C with ice.

The coupling component is precipitated by rapid addition of 470 L of glacial acetic acid.

CouplingThe reaction mixture is heated to 38 C, and the filter diazonium salt soln is run in under the surface of the suspension of the coupling component within 3,5 h. After completion of coupling, the pigment is isolated by filtering the suspension thro a press, washing to remove salt and drying at 50-55 C. The yield is 1400 kg

Copper Phthalocyanine Blue

BLUE PIGMENT CuPc (Copper Phthalocyanine) Blue pigment CuPc is one of the most stable pigments towards light, temperature and chemicals and hence, combined with its attractive colors, this pigment is widely used in many applications such as in paints water & solvent based paints including automotive paints), in water & solvent based inks, in textiles and in plastics with temperature of operations up to 350 C.

In industry, this pigment is produced in two stages The first stage is the preparation of the Blue Crude CuPc while the 2nd is the Pigmentation of crude CuPc ie the reduction of particle size of Crude CuPc.

Copper Phthalocyanine Blue

CRUDE CuPc Blue

Crude CuPc is commonly prepared by reacting copper chloride urea, phthalic anhydride, catalyst with solvent.

• CuCl + 12 H2NCONH2 + 4 C6H4 (CO)2O CuPc + NH3 + CO2 + H2O + NH4Cl (produced in Malaysia)

• Structure of CuPc Yield 90%

Production of Crude CuPc according to Patent

Phthalic anhydride 1000 kg, urea 1350 kg, and trichlorobenzene 3000 kg are mixed in a vessel equipped with an oil bath and stirrer: 240 kg of copper(II) chloride and 5 kg of ammonium molybdate are then added.

The mixture are heated up slowly within 1 hour to 200 C . Gas evolution mostly CO2 and some NH3 with formation of phthalimide begins at 130 C. Formation of CuPc begins at 160-170 C, with simultaneous released of CO and NH3. After stirring at 200-205 C for 1 hour, formation of the pigment is complete.

The Phthalocyanine is filtered of ; washed with hot trichlorobenzene at 50 C, methanol and hot water; and dried.

The yield of CuPc is 870 kg( 90%)

GLASS LINED PRESSURE REACTOR

ROTARY VACUUM DRYER

Filter Press

Spin Flash Dryer

Department

Duty

Purchasing To buy raw materials, machinery, lab equipments, spare parts of machinery and packaging etc

QC To set the standard and control the quality of the raw materials, finish products and packaging

R&D To produce new cheap products which satisfy customers requirements based on preliminary research by Technical Support

Production To produce consistent products

Marketing To find the market for the products and to set the quarterly sale forecast

Engineering To repair the damage and worn out parts of machinery

Technical Support To research customer complains regarding with quality & packaging problems and to prepare test methods for the finish products suitable for customers and to do preliminary research for new products based on customer’s requirements

Product Specification of Crude CuPc

Parameter Specification Test Method Number

Purity 97 % min TM 1

Moisture Content 1 % max TM 2

Water Soluble Matter 1.5 % max TM 3

Alcohol Soluble Matter 2.0 % max TM 4

pH 4 - 8 TM 5

Conductivity 800 mho TM 6

Total Grit 300 ppm max TM 7

Iron 20 pieces max /100 g TM 8

Sand 30 pieces max / 100 g TM 9

Fiber Trace TM 10

Free Copper Content 3000 ppm max TM 11

PCB 0.1 ppm max TM 12

PROBLEMS OF MANUFACTURING CRUDE CuPc

1. YieldThe yield of reaction is max 90% based on copper chloride used (see List of Patents). There are therefore about 10 % of the reagents used are disposed as waste.

2.. Environmental EffectMost of the waste of the production of crude CuPc (11,000 tons/yr) is precipitated using Na2S and then is buried underground

Pigmentation Process

Methods Pigments Produced Notes

Dissolving in conc H2SO4 and then sprayed into aqueous solution containing certain additives

Blue Pigment 15:0

Blue Pigment 15:1

Blue Pigment 15:2

Reddish blue pigment with heat stability up to 170 C and poor solvent resistant

Reddish blue pigment with heat stability up to 350 C but poor solvent resistant

Reddish blue pigment with heat stability up to 350 C and good solvent resistant

Grinding with inorganic salts with the aids of polyol solvent in the presence of certain additive in kneader or ball mill

Blue Pigment 15:3

Blue Pigment 15-4

Greenish blue pigment with tendency to agglomerate

Greenish blue pigment with solvent fastness

Kneader for Beta-CuPc

Ball mill for Beta-CuPc

Ball Mill

Pigmentation by Sulfuric Acid

Production of alpha –CuPc Pigment from crude CuPcCrude CuPc 700 kg is added quickly to conc. H2SO4 (96%) 6300 kg , and the temp is allowed to rise to 50 C . The suspension is stirred overnight.

When the phthalocyanine is completely dissolved , the suspension is sprayed into 35000 L of water at 70 C, and the temp is allowed to rise to 85 C – 90 C. The precipitated pigment is filtered off in a filter press and washed until acid free.

The presscake is then mixed with 25000 L of water, and the remaining acid is neutralized with K2CO3 and ammonia. After addtion of 35 kg of Lorol sulfonate the suspension is heated for 1 h until a clear filtrate is obtained.

After filtration of the suspension, the presscake is washed with hot water and homogenized with sufficient water to give a 20% paste, which is past 3-5 times thro a disintegrator (3000 rpm).

Pigmentation by Grinding

Production of Beta-CuPc Pigment from Crude CuPcIn a kneader , 283kg of crude CuPc is ground for 8 hours with 1131 kg of NaCl and 283 kg of Diethylene Glycol (DEG).

Then this paste is boiled in 6000 L of water and filtered using filter press to remove water/soluble substances. Washing with hot water is continued until no water soluble substances can be found.

The presscake is then dried at 70 C – 75 C or using spin flash drier. A intensive greenish blue beta-CuPC is obtained.

Copper phthalocyanine Green

The most common organic green pigments are Phthalocyanine green

The Phthalogreens are made by halogenating CuPc blue to produce mixtures of CuPc in which many of the 16 hydrogen atoms on CuPc have been replaced by chlorine or mixture of chlorine and bromine atoms

The pigment vary from blue green to yellow green depending on the ratios of bromine to chlorine

The yellowish green are obtained with nine to ten bromine atoms per molecule

The Phthalogreens are economical and have good light fastness

Copper Phthalocyanine Green

1 The most common organic green pigments are Phthalocyanine green

2 The Phthalogreens are made by halogenating CuPc blue to produce mixtures of CuPc in which many of the 16 hydrogen atoms on CuPc have been replaced by chlorine or mixture of chlorine and bromine atoms

3 The pigments vary from blue green to yellow green depending on the ratios of bromine to chlorine

4 The yellowish green are obtained with nine to ten bromine atoms per molecule

5 The Phthalogreens are economical and have good light fastness

Copper Phthalocyanine Green

MARKET DEMAND for Copper Phthalocyanine World production of this product is over 110,000 tons/year while the gap between the world demand and the supply according to Business Analyst for Asahi Songwon Colors Ltd for 2011 is 19,000 tons / year.

PRODUCTION COUNTRIES Crude CuPc was used to be produced in Japan, Europe and America but now it has been shifted to mainly China and India due to lower labor cost and also mainly as the waste regulations of these countries are not strictly followed.

COST OF RAW MATERIALS USED (Jan 2011)

Phthalic anhydride

Cuprous Chloride

Urea

Ammonium molybdate

CuPc (just raw materials cost)

FOB Price of CuPc (from Baiyan China)

$ 1,500 / MT

$ 6,565 / MT

$ 350 / MT

$ 24,000 / MT

$ 3,517 / MT

$ 5,760 /MT

CALCULATIONS

Material Weight used for 1 MT CuPc

Unit Price / MT Cost

CuCl 191 kg $ 6,565 $ 1,254.00

Phthalic Anhydride 1143 kg $ 1,500 $ 1,714.50

Urea 1390 kg $ 350 $ 487.00

Catalyst 2.60 kg $ 24,000 $ 62.40

Total Cost CuPc $ 3,517.90 / MT

Profit

The profit for the manufacturers of this product would increase tremendously by using this new process. For example, a medium size manufacturer that produces 5000 MT CuPc/ year with the FOB price of the low quality CuPc is $5.76/kg, the expenses are as follow:

If the cost of raw materials ($3.52), packaging ($0.04) and energy ($0.44) to be $4.00/kg then to produce 5000 MT = $20m

And if the cost for machinery is assumed to be $1m so a 5 yrs depreciation= $0.2m/yr

And if the number of workers employed is 100 with salary assumed to be $300/month each, so salary = $0.36m/yr

Profit

Then Profit :

(5000 MT x $5.76) - $20m - $0.2m - $0.36m + (10% x 5000 MT x $5.76) = $8.24m + $2.88m$11.12m/yr (before depreciation of building, Interest & Tax)

The profit should be more than this as the saving cost for the waste treatment should be added to this amount.

SOLUTION TO THE PROBLEM

• Adding a small amount of another co catalyst would improve the yield tremendously up to 99.9%

• The co-catalyst could be added at the same time as other reagents before the reaction starts or in the middle of the reaction before the temperature reaches 160 C

• The general chemical formula of this chemical is a complex of X-fatty acid ester sodium salt