compound. A masterbatch consists ofpigment plus additives dispersed in asolid polymer carrier, usually inpelletised form. The converter takesthe masterbatch and “lets it down” (iemelts it or dilutes it) at concentrationsranging from 0.5% to 25% into clearpolymer in order to produced thecoloured plastic raw material with theproperties required. In the case of aTiO2 masterbatch, the loading of TiO2in the masterbatch is typicallybetween 40% and 80%. So, to obtaina 5% concentration of TiO2 in thefinished product, the let-down ratio(resin:masterbatch) using a 50% TiO2masterbatch must be 9:1. If a 60%TiO2 masterbatch were used, the let-down ratio would have to be 11:1.

There are a number of advantagesfor the converter in using plasticsmasterbatches. Instead of keepingstocks of ready-compounded materialin several different colours, he cansimply keep separate bins ofmasterbatch pellets and thus save oninventory cost and space. Workers atthe converter’s factory handle dust-free pellets, which represent less of ahealth and safety risk than fine-particle pigment powders. It is easierfor the converter to obtain optimaldispersion and consistent batch-to-batch colours using masterbatchesbecause the first-stage blending,dispersion and colour developmenthave already been carried out by themasterbatch manufacturer.

Masterbatches are normallysupplied as polymer-specific products,with the pigments and additivesdispersed in the polymer that willultimately be used for the “let-down”stage. Suppliers also offer universalmasterbatches, where the carriersystem is compatible with a widerange of polymers. Unless usedcarefully, universal masterbatches canlead to problems of homogeneity, withadverse effects on the physical andcolour properties of the final plasticproduct.

White and black masterbatches,based on TiO2 and carbon blackrespectively, are widely used. Calciumcarbonate and lithopone, togetherwith TiO2, are also incorporated intowhite masterbatches, particularly inEurope. For yellow and red plastics,iron oxide and mixed metal oxidepigments are often used. However,there has been a rapid decline overthe past 10 years in the consumptionof some of the other inorganic redsand yellows, based on cadmiumsulfide or selenosulfide, leadchromate or molybdate. To someextent, colours based on heavy metalpigments have been replaced bycolorants incorporating higherloadings of TiO2, iron oxides andorganic pigments (eg Hansa yellow).For example, a standard red colorantfor polyethylene film used to contain:82% cadmium pigment, 10% TiO2, 5%organic pigment and 3% iron oxide.The replacement colorant contains:45% organic pigment, 40% TiO2 and15% iron oxide. Because of theradical differences in the compositionof the “old” and “new” colorant, it canbe quite a challenge to attain exactcolour matching in the final product.

Another colour matching challengearises from the use of different basepolymers. In a car interior, theupholstery and door panels may bemade of PVC, the steering wheel ofpolyurethane, the instrument panelsand door trim of polypropylene, theglove-box cover of ABS and theswitches of polyamide. But the vehicledesigner insists on having a uniformcolour for all these items!

The colour of plastic productsexposed to strong sunlight tends tofade. Moreover, most organic pigmentsshow a much greater tendency tofade than inorganic pigments and thistendency tends to be accentuated inthe presence of TiO2. Fading of theorganic pigment can lead to anunacceptably high level of colourdifference, especially with yellows,oranges and reds. Introducing organicultraviolet-absorbers into theformulation can sometimes improvefade-resistance, but a better solutionis to use nickel or chrome titanates aspartial substitutes for TiO2 to provideopacity and background coloration.Weatherfastness is also an importantcriterion in certain applications: someorganic pigments can be adverselyaffected by conditions of mildly acidic

rainfall or high atmospheric moisturelevels.

Final products, especially plasticfilms, are becoming thinner and yetthe requirement for opacity remainsthe same as before. Essentially, thisnecessitates higher loadings of TiO2or carbon black in the masterbatch. Inthe US, loadings of 75-80% TiO2 arequite common nowadays, whereasEuropean masterbatch formulationsare typically still based on 60%loadings. But higher pigment loadingstend to have an adverse impact onviscosity and dispersibility.

Clearly, the manufacture of plasticsmasterbatch is becoming increasinglysophisticated, demanding investmentin scientific research and closecollaboration with plastics processorsand their customers. Ongoing growthof 4-5% per annum in the world’sconsumption of plastics provides agood incentive for the leadingmasterbatch suppliers to meet thetechnical and market challengesahead.

Reg Adams

MARKETSWorld zircon shortage looming?

Global zircon demand is rising muchfaster than supply, one of the majorfactors being the continued boom insales of zircon to the ceramic tilesector in China. Most zircon isgenerated as a by-product at ilmeniteor rutile mines, so that the supply ofzircon is geared mainly to the demandfor TiO2 feedstock from pigmentmanufacturers. World zirconproduction is estimated at 1.089 Mtonnes in full-year 2002 and it isforecast to increase to 1.119 M tonnesin 2003. Australia and South Africacurrently account for about 77% ofworld zircon production, with themajor suppliers being Iluka Resourcesand Richards Bay Minerals (a 50:50joint venture between Rio Tinto andBHP Billiton).

For full-year 2002, world zirconsupply increased by 3.8%, butdemand rose faster than this,resulting in a deficit of 1200 tonnes.Zircon use in ceramics is expected torise from 571,000 tonnes in 2002 to589,000 tonnes in 1993 and to626,000 tonnes by 2005. Total world

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World: Plastics Colorants Demand(‘000 tonnes)

Total 2300Titanium dioxide 900Other white pigments 400Carbon black 600Inorganic colours 350Organic colours 50

consumption of zircon is forecast toreach 1.188 M tonnes/y by 2005.

Industrial Minerals, May 2003, (428), 42-45

Honeywell forecasts strong growth inusage of luminescent pigments

According to Honeywell, USconsumption of luminescent pigmentsfor safety applications increased by50% last year. US consumption overthe next few years is forecast to riseat 20-30% per annum. Meanwhile, inEurope demand is strong forluminescent pigments to provide after-glow in safety guidance systems. Themajor end-uses for luminescentpigments are in: brand security andauthentication (ie anti-counterfeitingmeasures).

Honeywell itself manufactures theLumilux range of pigments at Seelze(Germany) and is keen to widen thepalette of available colours.

Chemical Market Reporter, 24 Mar 2003 (Website:http://www.chemicalmarketreporter.com)

Chinese, German & Indian suppliersdumping optical brighteners in the US?

The position regarding possibledumping of optical brighteners in theUS market is a little confused. In earlyApril 2003, the US International TradeCommission announced that it hadbegun investigating allegations thatoptical brighteners from China,Germany and India were being sold inthe US at less than fair value. Theinvestigation was apparently sparkedoff by a complaint from Ciba SpecialtyChemicals. Then, on 10 April, the USDepartment of Commerce (USDC)announced that it had receivednotification from Ciba that the companywanted to drop its complaint.

On 14 May, the USDC reportedthat it had received an anti-dumpingpetition from Ciba. Supplementaryinformation was provided on 27 Mayand 29 May. Ciba alleges that exportsof optical brighteners from India arebeing unfairly subsidised by the IndianGovernment. The formal petitionnames the products under scrutiny as:4,4’-diamino-2,2’-stilbenedisulfonicacid (DAS) and stilbenic fluorescentwhitening agents (SFWA). DAS isessentially an intermediate, which isquite widely used to produce SFWA,which are synthetic organic productsnormally used as fluorescent

brightening agents in the productionof certain textiles, papers anddetergents.

Federal Register, 8 Apr 2003, 68 (67), 17084-17085 &10 Jun 2003, 68 (111), 34582-34584 & 10 Jun 2003,68 (111), 34579-34584 (Website:http://www.gpoaccess.gov/fr/advanced.html)

India levies duties of up to $358 pertonne on Chinese anatase TiO2

The Designated Authority in theDirectorate General of Anti-dumping &Allied Duties has investigated claimsof dumping of Chinese anatase-typeTiO2 on the Indian market, followingcomplaints by Travancore TitaniumProducts (TTP of Trivandrum),Kolmak Chemicals (of Kolkata) andKilburn Chemicals (of Chennai). Theinvestigation focused on importsduring calendar year 2002. Thecomplaints were upheld and provisionalanti-dumping duties have beenimposed as follows: $303.70 per tonneon imports from Shaugan ChemicalWorks; $313.01 per tonne on importsfrom Guangxi Dahua ChemicalWorks; $342.34 per tonne on importsfrom Guangxi XiXing MeiXiangTitanium Manufacturing Co; and$358.04 per tonne on imports from allother Chinese suppliers.

Business Line, 14 Jun 2003, 10 (164), 4

China’s organic pigments outputapproaches 100,000 tonnes/y

China’s production of organic pigmentsincreased by 11.15% to reach 95,700tonnes in 2002. Meanwhile, thecountry’s production of dyesincreased by 31.33% to reach421,300 tonnes. The production ofdisperse dyes increased by 29% to226,000 tonnes, while the output ofreactive dyes increased by 34.1% to38,000 tonnes.

The leading producer of organicpigments was Shanghai BASF, a51:49 joint venture between BASFColorants and Shanghai Dyestuffs.This company increased its organicpigment output by 2.23% to 11,302tonnes in 2002. Hebei JiehongPigment & Chemical Industrial Co Ltdwas the second largest producer, with8400 tonnes.

The leading producer of dyes wasZhejiang Longsheng Group Co Ltdwith an output of 70,892 tonnes in2002, up 56.4% on the 2001 figure. In

second place was Zhejiang RuntuChemical Industrial Group Corp,which registered a 52% increase inoutput to 59,412 tonnes last year.

Exports of organic pigments roseby 13.4% to 82,000 tonnes, worth$79.49 M. Major destinations were:Taiwan (21,600 tonnes, valued at$52.72 M); the United States (13,320tonnes, valued at $51.78 M); andGermany (7420 tonnes, valued at$40.6 M). Imports of organic pigmentsinto China increased by 11.1% to30,340 tonnes, with Taiwan andJapan being the major suppliers.

China Chemical Reporter, 26 Apr 2003, 14 (12), 21-24

7%/y growth in demand for minerals inNorth American plastics

Minerals used as reinforcements,pigment extenders and fillers findapplication in a variety of end-useapplications in paint, paper, plastics,rubber, inks, etc. In this context, totalNorth American demand exceeded 15M tonnes, valued at $1.9 bn, last year.The paper industry is the dominantend-use sector, accounting for roughly50% of consumption by volume. Untilabout 10 years ago, the plasticsindustry was a comparatively minorconsumer, but it is now the secondlargest, with an intake of 2 M tonnes,valued at $500 M. (These figuresexclude TiO2 consumption).

The plastics sector tends toconsume relatively expensiveminerals, the average price tag being$225 per tonne – about twice theoverall average for all end-usesectors. Plastics compounders workwith a variety of minerals, includingcalcium carbonate, talc, aluminatrihydrate (ATH), silica, mica, kaolin,diatomite and wollastonite. Since1980, the tonnage consumption ofthese minerals in plastics hasincreased by 7%/y. Over the sameperiod, North America’s consumptionof plastics has increased by 4-5%/y.In 1980, about 9% of all plasticsincorporated minerals. By 2002, thefigure had risen to 15%.

Some of the attractive markets formineral-filled plastics include:polypropylene for decks, railings,automotive interior panels and seatbacks; polyvinyl chloride (PVC) forwindow/door frames; nylon for high-heat connectors, automotiveunderhood applications; ATH and other

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