Document 6QjNrL6nxK7XkmaXgygzkm81

Cosmetic talc properties and specifications By R o n a l d W. G r e x a and C. J. P a r m e n t i e r Cyprus Industrial Minerals Company, Los Angeles, CA TJ- ale deposits are most commonly formed by hydrothermal or metamorphic alteration of pre existing rocks. Figure 1 depicts an aerial view of a Montana talc deposit which is situated ap proximately 6,500 feet above sea level. The de gree of alteration and the nature of the rocks from which the talc was formed largely deter mine purity and particle shape. The whiter, purer talcs are derived from dolomitic limestone and constitute the most likely cosmetic talc can didates. Figure 2 gives a closer view of the same Montana talc deposit. This is an open pit deposit lined using bench mining techniques. Figure 1. Aerial photograph of Montano tak deposit. The mineral talc is a hydrous magnesium sili cate, with the composition 3MgO 4SiO , HsO. Large bodies of pure mineral are rare; therefore the commercial term " talc" has varying degrees of meaning. It refers to various rocks composed of magnesium silicates in which talc may be dominant, abundant, minor, or entirely absent. The greater the amounts of impurities, the less desirable the talc for cosmetic purposes. One common impurity is tremolite, 2CaO 5MgO t "'S i0 2 HjO. This mineral has been defined by Figure 2. Montana tak depotrt. the Occupational Safety and Health Administra tion (OSHA) as an asbestos-mineral and is pres ent in many but not all commercial talcs. Other impurities include chlorite (5MgO . Al: 0 3 . 3SiOj 4HjO), dolomite (Ca, M gC03), calcite (CaC03), iron oxide, carbon, quartz, and man ganese oxide. Table I indicates the varying compositions of talc from different locations. The structure of pure talc minerals consists of a brucite (MgO) sheet sandwiched between two silica sheets, forming talc layers which are superimposed indefinitely. Each layer is electri cally neutral; adjacent layers are held together by only weak van der Waals forces. Figure 3 shows a cross section of a typical talc plate. Crude talcs' range from white to green to brown in color. After being ground to powder, Ili' 12 0 " (OHJjttjjfiijO,), - TALC eorrespondence io Ronald W. Gr#xa, Cypru* Industrio! M in erai Com pony, Sulle 21 A, 1901 N. O ldon Ave. Extention, Trenton, NJ 08618. Figur* 3. Moleculor iiructur* of pur* role mineral. /ot. 94, F e b ru a r y 1 97 9 0361-4387/79/0002-2901 $02.00/0-- ) 1979 Allured Publiihing Corp. C o s m e t ic i 8. Toileiries/29 lI I i I BASF EMTAL000005184 T a b le!. Talc MiN:ral Composition U i^ a l Talc Tremolite A n ta b h y llite Ser^m tire Qu.tnz Chlw ite DolN:rite C a lcite \laomposite Montan* 90 - 95% <i 2 ab J l , 0 Vo m ont " 92% 2' - '. 1 '.2 5- ) tab " 92% -0 <1 10 5 ). I 2 [ pure talcs have varying degrees of whiteness. Figure 4 depicts a crude rock from Montana. The pure talc mineral is characterized by its ex treme softness, hydrophobic surface properties, micaeous structure, and slippery feel. Although pure talc is the standard of one on the Mohs Scale of hardness, some commercial talcs m`ay exhibit more abrasive properties due to the pres ence of impurities such as dolomite, calcite, tremolite, and quartz. Cosmetic talc is lamellar in particle shape and this stricture produces the slippery feel. This occurs where the platy talcsheet slides over another sheet. This shearing action tends to delaminate the talc stacks. Commercial talcs are mined in a variety of ways, including straightforward drill, blast and Nabth Carolina " - 92% - 5. 0 - ). I , 5 ab . 2 - New York 35 )0 iO ) 5- 2 ). 1 * 2 0 2 I ). 1 C alifw ua " . M% 12 ' 'I ). ' Franco . `i " * 10 . - Figur 5 . Crude tole o!Mn pit mining. Figure 4. Montono tole erude rock. shovel, and open pit operations such as shown in figure 5. Other deposits must be mined with complicated underground equipment. The crude rock is then transported to the mill for processing. Figure 6 shows a talc mill which is situated in Three Forks, Montana. Traditional processing involves crushing with a jaw-type crusher and then milling in a roll-type mill. Figure 7 depicts a Raymond Roller Mill used for talc grinding. The product is collected in cyclones and bag ged. Dust is controlled by " bag house" dust collectors. Conventional cosm etic talcs for dusting and baby powder applications are usu ally manufactured in this manner. These mate rials are normally ground to specifications of 98% minimum through a 200 mesh (74 i ^m) screen. Other products are ground to a fineness o f 99.9% through a 325 mesh (44 ^.m) screen 30/Cosm etics & Toiletries - Figure 6. Talc mill in Th,.. Forks, Montana. using additional milling equipment and air clas sification. These products arc used in aerosol and makeup applications. In many industrial talc applications, liner par ticle size products with a median particle size of 1 ^m are required. These products are not, how ever, suitable for cosmetic applications. Many talcs in their natural state are unsuitable for cosmetic applications. If this is the case, up grading procedures must be used to make the talc acceptable to meet cosmetic specifications. Upgrading techniques include floatation antlior acid leaching to the degree of chemical purity and color needed. However, this upgrading is an expensive and energv-intensivc additional pro cessing step which is avoided if at all possible. There are some high quality cosmetic tak de posits in the U.S. which do not need hcncfac- Vol. 94, F e b ru ary 197C BASF EMTAL000005185 Figur 7. Raym ond roller mill. tion, the most notable of which are in Montana and North Carolina. There are also some depos its in the Death Valley area of California which are pf cosmetic quality but may contain varying amounts of the asbestos-mineral tremolite. Although much has been said about accept able cosmetic talcs from a fairly general standpoint, not much in the way of specifics has been discussed. Basic criteria for a cosmetic talc follow, apparent density asbestos content microorganism content fragrance stability slip color Some of those criteria can be found in the recent Cosmetic, Toiletries and Fragrance Association (CTFA) description of cosmetic talc; all are part of each manufacturers in-house specifications. The apparent density of a cosmetic talc prod uct is its bulk density represented as lbs/ft3. This figure is essential information for the cosmetic manufacturer as it has specific filling require ments depending on the size containers used. Apparent densities can be determined using both loose and tapped methods. CTFA Method C-7 calls for the use of a dropping box which is operated by hand. This box is pictured in figure 8. The loose method calls for a free fall proce dure using density equipment shown in figure 9. The tapped method is used by most of the cos metic industry; however, variations of this method prevail which make comparisons impos sible. If a cosmetic chemist compares the liter ature of one, supplier who uses CTFA Method C-7 (hand tap to constant volume) to another supplier who uses CTFA equipment but only taps 100 times, the results will not be the same, even 1 the same tale is used. In addition, some Vol. 94, February 1979 Figure 8. CTFA dropping box for tapped denitties. Figur 9, Loom density devio. manufacturers use an automated system similar to figure 10, which further complicates the situ ation. Figures 11 and 12 illustrate an interesting contrast between CTFA C-7 method, which calls for hand tapping with specific time intervals, versus the use of the automatic tapping device shown in figure 10 at various taps. Samples 1 and 2 are different particle cosmetic talcs from Montana. In both instances, the automatic de vice did not alter the bulk density to any great degree, indicating the continued presence of entrapped air, while the hand tap method re moved this air and eventually gave a constant density value. Apparent density is proportional to the parti cle size distribution of the talc product. Therclorc, control of particle size at the mill is csscn- Cosmetic & Toiletries/31 BASF EMTAL000005186 Figur* 10. Automatic tapping d*vic*. tial in order to control apparent density. In other words, the finer the .distribution the lower the apparent density and vice versa. However, there are particle size limits which cannot be sur passed. If these limits are surpassed, the product may be too.dense and gritty or too fine and flufFy. Up until the late 1960s and early 1970s, the mineral compositions of cosmetic talcs were not specified. This all changed with the advent of the 1972 OSHA regulations concerning asbestos-containing minerals. Today the CTFA specifies that a true cosmetic talc must contain at 32/Cosmetics & Toiletries least 90% hydrous magnesium silicate with detectable asbestos minerals, using toehniqi: specified in CTFA Method J-4. Other itnpnrit such as iron, crystalline silica,""and curbonat are covered but are ofless consequence. As technology and federal regulations creased, the need for bacterial control arose, one time no thought was given to bacterial v* lamination in cosmetic talc, but today all c metie houses have some bacterial specificatii including general plate count, yeasts, molds, a gram negatives. Table II shows a typical bacterial specifi tion. Some manufacturers' specifications are : as stringent as others', but all cosmetic m. ufacturers acknowledge the need for controls this area. Table II. Bacterial Specificattom Cenerai plate count Molds Yeasts Cram negatives LOO/g 100/R 100/R None detectable Although not usually mentioned on cosin manufacturers' raw material specification she fragrance stability is essential. A specific t metic talc must be able to hold a particular grance oil on its surface and release it changed. This criterion more than any othei fects the approval or rejection of a particular candidate by a cosmetic manufacturer. After the cosmetic manufacturer is really selling grance, with talc as a carrier. The only wa; 'check this criterion is by actually testing the with a specific amount of fragrance oil ur room temperature and elevated temperai conditions. Elevated temperatures are use obtain stability data which are indieativi long-term shelf life. -An experienced perfu can detect minute differences. Many times fragrance oil is completely masked by the leaving no fragrance at all. Unfortunately, area is still more an art than a science; method of trial and error is applied. Another criterion which is also not quan tive is " slip," the smoothness of the talc proi as felt by the human hand. This is strict subjective area where each cosmetic mani turer has its own interpretation. The slip cosmetic talc product is dependent on the and shape of the individual particles that c prise the product. The larger the indivu plates, the better the slip. Figure 13 show electron photomicrograph of a delaminated particle. Italian talcs have had and continue to have cellent slip characteristics. Unfortunately, t cost has lim ited their use in the U.S. > domestic talcs of various origins with adeq' slip characteristics and reasonable costs 1 overtaken the marketplace. The last major concern is color. This is a important factor because most cosmetic talc* discolored by the fragrance oil anyway. H ever, they should be a certain degree of whit Vot. 94, Februc # BASF EMTAL000005187 Figur# 13. Electron photomicrograph of d#laminated talc particle. Other less important specifications include water soluble substances--especially iron, acid soluble substances, loss on ignition, lead, arse nic, mercury, nickel, and sulfur content. These additional variables do not affect the physical properties of the cosmetic talc but can have a chemical effect when combined with other raw materials in the cosmetic formulation. There is an additional set of criteria for USP grade cosmetic talcs. These talcs are usually used by pharmaceutical firms and must meet the U.S. Pharmacopeia standards outlined in Table III. One must remember that many phar maceutical products are ingested into the body; therefore acid- and water-soluble substances Tabic Hi. IJSP Specifications Acid soluble} as SO^ L o u on igni libri Water soluble iron Water soluble substances 2% m inim um 5% maximum none detected 0.1% maximum Must meet talc identification test take on added significance. As can be seen, cosmetic talc has unique properties, which limit the number of talcs avail able to the cosmetic industry. On a worldwide basis, cosmetic tale is in short supply. This in cludes the U.S, where high quality cosmetic talc is much more difficult to obtain. Up until re cently, U.S. cosmetic manufacturers relied on North Carolina, Vermont, Alabama, and Italian talc products as their only talc sources. How ever, the introduction of a high quality cosmetic talc out of a large deposit in Montana has greatly eased the situation. The talc in this deposit is of extreme purity and whiteness, meets all CTFA requirements for cosmetic talc, and has an ex cellent reserve picture. It is, in fact, the purest talc commercially available today. In conclusion, a true.cosmetic talc has its own particular traits--established by the cosmetic industry years ago as well as by federal regula tions* Therefore, it can be stated unequivocably that true cosmetic talc is the purest form of talc available com m ercially and bears no re semblance to the many industrial talcs that have fallen under investigation recently for a variety of reasons. From cxjr research lAboRATORiES..,, WE o f fER UNKpUE bASE COMPONENTS CUSTOM TAlloREd foR "s^AM pOO-iN" COlOR SYSTEMS fEATURiNq: MAXIMUM eo lO R SubsTANliviTy OUTSTAINidiiVCj CONdiTiONiNq En IhANCEcI STAbiliTy 0 Lowe^ tein dyES COSMETICS, INC. 420 MORCjAN AVENUE R O O k lyN , NEW y O R k 11222 TElEphONE: (2121> 6 0 -5 4 1 0 * CaU e : "jOCloWE^NEW yORk TeI eX: 2>5002 lOWE UR : < 1 c1 1 ! V o t. 9a, February 1979 Cosm etics & Toilefries/33 BASF EMTAL000005188