112 -2 Coatings Technology Handbook, Third Edition 112.3 Types of Coating There are two main types of tablet coating done today: sugar coating and film coating; film coating is the more popular. Coated tablets fall into three main subcategories depending on how the drug is released: immediate release, enteric release, and sustained release: Immediate-release coating systems, as the name implies, allow immediate release of the drug com- pound to the body. Enteric coatings are soluble only at a pH greater than 5 or 6. Thus, the drug is not released in the stomach but in the small intestine. Enteric coatings are by far the most unreliable because of the wide and unpredictable variance in gastric pH profiles. Gastric pH varies considerably based on stomach content, age of the patient, and disease state. Sustained-release coatings permit drug to dissolve slowly over a period of time. This helps to reduce dosing intervals and improves therapeutic reliability. Film coating can be carried out using either an organic solvent system, such as ethanol or methylene chloride, or by using water as a solvent. The solvent film coating systems are fast disappearing because of cost, environmental, and safety concerns. Most film coating carried out today is done with aqueous systems. 112.3.1 The Sugar-Coated Tablet The sugar-coated tablet is the most elegant solid dosage form produced today. Its glossy appearance, slippery feel, and sweet taste are unmatched by any other coated tablet. The sugar-coated tablet is also the most difficult and time-consuming to produce. The tablet consists of a core upon which layer after layer of coating material is slowly and carefully built up. In some cases this is done by hand and in other cases automatically. In any event, there is still an art to sugar coating. To successfully accept a sugar coating, the tablet cores must be robust. They are subjected to wetting and rolling in a coating pan with 50 kg or more of other cores. Generally the coating pan is spherical and has a solid exterior surface. Temperature-controlled air is introduced and removed from the pan via external ducts. The following procedure is used for the manual sugar coating of tablets. The first step is to slightly waterproof the tablets by applying a coat of pharmaceutical-grade shellac. This prevents the cores from dissolving prematurely in the presence of the other coating liquids that are to be applied. The second step is subcoating: a solution composed of acacia, gelatin, and sugar is applied to the tablets. The wetted cores are then dusted with dicalcium phosphate or calcium sulfate and allowed to dry. This step is repeated many times until a smooth rounded tablet form has been achieved. The third step is the grossing coat. The cores are wetted with a sugar solution and dusted with titanium dioxide powder. This creates a very white base coat on which color may be applied. The fourth step is the color coat. In this instance an insoluble opaque color solid is suspended in sugar syrup and applied to the tablet. No dusting of the cores takes place. The tablets are simply air dried. The fifth step is the shutdown coat. In this step diluted sugar syrup is applied to the tablet and allowed to dry. This produces a very smooth finish in preparation for the last step. The last step is polishing of the tablets. The tablets are placed in a canvas-lined drum. Beeswax or carnauba wax is dissolved in methylene chloride, and the solution is applied to the tablets, which are tumbled until the solvent evaporates and tablets achieve a very high shine. In all, 40 or more separate layers are applied during the manual sugar coating process. The process takes between five and eight 8-hour shifts to complete. Automated sugar coating is generally faster. For example, the various syrups used in the coating process have the dusting powders suspended in them. The syrups are applied by spray. This process can be automated to reduce the number of operators required. Perforated coating pans, which greatly enhance DK4036_book.fm Page 2 Monday, April 25, 2005 12:18 PM © 2006 by Taylor & Francis Group, LLC Pharmaceutical Tablet Coating 112 -3 air throughput, are used almost exclusively. With greater air throughput, water evaporates more quickly, thus speeding the process. Using automated techniques, tablets can be sugar coated in about 16 hours. 112.3.2 The Film-Coated Tablet The film-coated tablet consists of a core around which a thin, colored polymer film is deposited. Thus, a film-coated tablet gains about 3% of total tablet weight upon coating. The sugar-coated tablet undergoes a 100% weight gain. Overall, film coating is a much faster procedure, and much less prone to error. The basic film coating formula consists of a film former, a pigment dispersion, a plasticizer, and a solvent. A variety of polymeric film formers can be used to coat tablets. By selecting the solubility properties of the polymer, one can produce an immediate-release, an enteric-release, or a sustained- release tablet. The most popular immediate-release film formers are the water-soluble cellulose ether polymers. The two most common are hydroxypropylcellulose (HPC) and hydroxypropylmethycellulose (HPMC). The low viscosity grades of these polymers are employed in the coating formula to maximize polymer solids concentration. Both these polymers are water soluble. Water-insoluble film formers can also be used to prepare immediate-release coatings. These products fall into two categories: cellulose ethers and acrylate derivatives. The most common cellulose ether is ethylcellulose. This material is commercially available in two forms: as pure polymer and as an aqueous dispersion. The pure polymer is generally dissolved in an organic solvent; the dispersion is delivered out of an aqueous media. In both cases, a certain amount of water-soluble component (up to 50% of the total polymer solids) is included in the coating formula, to provide immediate drug release. The ethylcellulose and acrylate compounds are also used to formulate sustained-release products. Again, a water-soluble component is included in the coating formula. However, the level is very low: usually about 3% of total polymer solids. When the coated dosage form is exposed to water, the water- soluble component dissolves. This leaves a porous film surface through which drug diffuses. The third class of coatings, the enterics, resist the attack of gastric fluids. As a result, drug is released only in the small intestine. Enteric coatings are prepared by using a polymer with pH-dependent solubility properties. Cellulose esters, substituted with phthalate groups, are the primary polymers used in this application, especially cellulose acetate phthalate. Polyvinyl acetate phthalate is also used. Acrylate deriv- atives are also capable of providing enteric release. 112.3.3 Compression Coating Compression coating is a technique wherein a large tablet either completely or partially surrounds a smaller tablet. Essentially, a small tablet is compressed first and is then surrounded by powder, which undergoes compression. This type of coating technique requires the use of special tableting machinery and it is used to produce sustained-release tablets. Bibliography Florence, A. T., Ed., Critical Reports on Applied Chemistry , Vol. 6, Materials Used in Pharmaceutical Formulation . London: Blackwell Scientific Publications, 1984. Lachman, L., H. A. Leiberman, and J. L. Kanig, Eds., The Theory and Practice of Industrial Pharmacy , Philadelphia: Lea & Febiger, 1st ed., 1970; 2nd ed., 1976; 3rd ed., 1986. Osol, Arthur, Ed., Remington’s Pharmaceutical Sciences . Easton, PA: Mack Publishing Company, 14th ed., 1970; 15th ed., 1975; 16th ed., 1980; 17th ed., 1985. DK4036_book.fm Page 3 Monday, April 25, 2005 12:18 PM © 2006 by Taylor & Francis Group, LLC 113 -1 113 Textiles for Coating 113.1 Yarns 113- 1 113.2 Fabrics 113- 2 Bibliography 113- 12 Woven or knitted fabrics, and various types of nonwoven product, may be used as coating substrates. The physical–mechanical properties and the end-use performance of the coated fabrics depend signifi- cantly on the type of coating polymer and the substrate characteristics. Textile structures used for the backing of coated fabrics are complex three-dimensional constructions. The properties of these textile structures are determined by particular properties of constituent fibers and the construction of yarns and fabrics, as well as finishing processes. Knowledge of the characteristics of backing and its mechanical behavior is essential for predicting and understanding the properties of various coated materials. 113.1 Yarns Processing of coated fabrics involves a wide range of natural and man-made fibers. Cotton and other vegetable fibers are the most important natural fibers used for backing. The types of man-made fiber most widely used for backing are high wet modulus viscose, polyester, polyamide, acrylic, polypropylene, polyethylene, and aramid fibers. It is well known that fiber properties are determined by the nature of the chemical composition, by the molecular and fine structure of the constituent polymer, and by the external structure of fibers. The fibers mentioned are used in the form of staple or yarns for the manufacture of woven, knitted, or nonwoven structures for backing. There are two general classes of yarns: spun yarns made from natural and man-made staple fibers or their blends and continuous filament (multi- and monofilament) yarns. Spun yarns are an assemblage of partly oriented and twisted staple fibers of relatively short definite length. The fibers in yarn are held together by twist, which causes the development of high radial forces and friction between fibers. Because of friction between fibers, the yarn obtains tensile strength and compactness. The fibers lie at varying angles to the axis of the yarn, with the fiber ends sticking out from the surface. The hairiness and the bulk of spun yarns play important roles with regard to absorbency and adhesion properties of backing materials made from these yarns. The amount of twist also determines the mechanical properties, first of all the breaking force and extension of spun yarns. Continuous filament yarns are made by extruding the fiber forming polymer (solution or molten mass) through the holes in a spinneret. Filaments obtained by this way are long continuous fiber strands of indefinite length. The number of filaments is determined by the number of holes in the spinneret. Continuous filament yarns are characterized by a smooth, compact surface formed by parallel packing of straight filaments with minimal air spaces between them. Yarn made from one continuous filament is called monofilament yarn. Continuous filament yarns may be twisted or intermingled, to obtain required degrees of compactness and structure. Algirdas Matukonis Kaunas Technical University DK4036_book.fm Page 1 Monday, April 25, 2005 12:18 PM © 2006 by Taylor & Francis Group, LLC Woven Fabrics • Knitted Fabrics • Nonwovens Textiles for Coating 113 -3 1 twill is arranged with the twill wale going in the reverse direction. Since the relative amount of interlacing in the twill weave is less than in a plain weave, yarns can be packed closer, producing a thicker cloth. On the other side, fewer interlacings diminish the interfiber friction, which contributes to a greater pliability, softness, and wrinkle recovery of fabrics, but makes for lower strength. For backing manufacturing, a 2/ 2 twill is widely used. The satin weaves (Figure 113.3) have long yarn floats (over four yarns minimum) with a progression of interlacing by definite number (over two yarns minimum). When warp yarns predominate on the face of the fabric, we have a warp-faced fabric — satin with a higher warp count. If the weft covers the surface, the fabric is called sateen. The filling count of sateen fabrics is higher than of warp ends. The few interlacings of satin weave fabrics increase the pliability and wrinkle recovery, but also increase yarn slippage and raveling tendency. Fabrics of this type have a smooth, lustrous appearance because of the long floats. Manufacturing of heavyweight coated materials requires corresponding woven backing with distinct thickness and mechanical properties. For this application, fabrics of two or more layers are used. The construction of four-layered fabric based on plain weave is shown in Figure 113.4. For improving adhesion and absorbency as well as the aesthetic properties, various fabrics can be napped during finishing on one or both sides, producing a layer of fiber ends on the surface of the cloth. The weave of fabric used for napping usually must be filling-faced because of the raising ability of the long weft floats. The most dense and durable three-dimensional pile cover is produced by means of special techniques. There are two ways to manufacture woven pile fabrics: using weft-pile and warp-pile technologies. In the weft-pile fabric (velveteen and corduroy) an additional set of filling, usually staple yarns with floats, is used. After weaving, the surface floats are cut and brushed, producing a dense, stable pile cover (Figure 113.5). In warp-pile fabrics (velvets, plush, furlike fabrics), an extra set of warp staple or multifilament yarns is used. One very productive approach is the double-cloth method of warp-pile fabric manufacturing. Two parallel fabrics are woven in the special loom, face to face. The pile-warp interfacing connects both fabrics. As the pile is cut, two pile cloths are produced (Figure 113.6). In weft-pile fabrics the tufts of FIGURE 113.3 Satin weave: π yarn arrangement with the repeat of 5 × 5 yarns. FIGURE 113.4 Four-layered fabric (derived from plain weave). FIGURE 113.5 Weft-pile fabric. FIGURE 113.6 Warp-pile fabric (double-cloth method). DK4036_book.fm Page 3 Monday, April 25, 2005 12:18 PM © 2006 by Taylor & Francis Group, LLC 113 -4 Coatings Technology Handbook, Third Edition pile are interlaced around ground warp yarn, and in the warp-pile fabrics they are interlaced around ground warp ends. Some pile fabrics can be made very efficiently by tufting and punching extra yarns into woven base fabric by a series of needles, each carrying a pile yarn from a creel. The tufting pile can be cut or looped. The height of the pile depends on the type and end use of fabric. Velvet has a pile 1.5 mm high or shorter, velveteen not over 3 mm, plush usually 6 mm and longer, and furlike fabric 8 to 15 mm. Very important specific properties of all pile fabrics are the density of pile cover and resistance to shedding and pulling out. It must be noted that a coating polymer layer may be formed on the pile side of the fabric. Other methods of producing pile fabrics, such as electrostatic flocking, using chenille yarn pile, etc., are also known. The main structural characteristics of woven fabrics are linear density and count of constituent yarns, as mentioned previously, as well as weave, cover factor, and mass per unit area. Cover factor is expressed as follows: where d y is yarn diameter (mm), calculated on the base of linear density and apparent density of yarns, a y is yarn spacing, and S y is yarn count (number of threads per millimeter). Cover factor may be obtained for warp and weft yarns; it expresses the relative tightness of the fabric concerned. The magnitude of K in fabrics intended for coating varies in the ranges of 50 to 140% and 40 to 130% for warp and wefts, respectively. The mass per unit area (weight range) of fabrics depends on type and end use and varies from 40 to 400 g/m 2 or more. Among the wide range of mechanical characteristics, there are several determining the field of use of coated woven fabrics. First, the fabric must have the required tensile strength and elongation. The tensile strength of fabric as well as of yarns is expressed in terms of tenacity in specific units: centinewtons per tex (cN/tex). Tenacity is calculated on the basis of the breaking force of a 50 mm wide strip and the number of linear density of threads in the strained system. For approximate calculations, it may be assumed that the breaking force of a loaded thread system is expressed as the sum of the loaded yarn’s breaking force multiplied by a factor 0.8 to 1.2, depending on the weave, thread count, type of fibers and yarns, finishing processes, and loading direction. In some cases the conditional value of tenacity is evaluated on the basis of breaking force and the whole mass of fabric strained (as in the case of nonwoven materials). The conditional values of breaking force and breaking extension of woven fabrics of various types are represented in Table 113.1. The strength of high- tech fabrics made from high tenacity fibers (polypropylene, polyethylene, aramid, and others) may be much higher. The tensile behavior under load of fabrics of different types — woven, knit, and nonwoven — is shown There are also other characteristics of fabrics that determine the usefulness of these materials for coating purposes. Important properties are tearing force, resistance to cyclic loading, bending stiffness, TA BLE 113.1 Range of Breaking Characteristics of Woven Fabrics Type of Fabric Breaking Force (cN/tex) Breaking Extension (%) Warp Direction Weft Direction Warp Direction Weft Direction Cotton 5–7 4–7 4–8 16–24 Linen 6–8 5–6 5–21 5–8 Wo ol 2–5 1–3 20–28 28–33 Viscose 7–8 4–5 16–20 15–23 Nylon 20–26 7–16 20–22 26–28 K d a dS=× = × y y yy 100 100 DK4036_book.fm Page 4 Monday, April 25, 2005 12:18 PM © 2006 by Taylor & Francis Group, LLC in Figure 113.7. Textiles for Coating 113 -7 TA BLE 113.2 Comparison of Textile Properties Properties a Fabric Type Thickness Porosity Specific Vo lume Roughness Tenacity Braking Extension Tear Force Bending Stiffness Compressibility Elastic Modulus b Drape Coefficient Shear Strain Woven L/M M L M H L/M H L/M L M L/M M Knit L L/M M L M M M/H L M/H L L H Stitchbonded (Malimo) L M M M H M H M M M M M/H Adhesive-bonded L/M L/M M M L/M M L H L/M M M/H L Stitchbonded (web) M/H H H L M/H L/M M H M H L Spunbonded L H M M H H H M/H L H H L a L, low; M, medium; H, high. b Modulus of elasticity (initial) expresses the ratio of stress to strain at the beginning of the stress-strain curve. DK4036_book.fm Page 7 Monday, April 25, 2005 12:18 PM © 2006 by Taylor & Francis Group, LLC Textiles for Coating 113 -9 FIGURE 113.10 Multiaxial warp-knit fabric combined with prebonded web (made of Copcentra HS-ST machine, Liba, West Germany): 1, warp filler yarns; 2–6, weft yarn systems; 7, prebonded fiber web; 8, stitching warp system; 9, fabric formed. 9 7 2 1 3 4 5 6 90° 90° 90° +45 − 90° 90 − 45° 8 DK4036_book.fm Page 9 Monday, April 25, 2005 12:18 PM © 2006 by Taylor & Francis Group, LLC 113 -10 Coatings Technology Handbook, Third Edition technology, and combined technology. All techniques of nonwoven manufacture are characterized by a high operating speed and low fabric production costs in relation to conventional technologies. 113.2.3.1 Adhesive-Bonded Fabrics Adhesive-bonded fabrics are made by the physical–chemical method, in which webs of fibers are strength- ened by fiber-to-fiber adhesion. The web is prepared on special equipment based on carding or the aerodynamic principle; such machinery is capable of producing webs with random or oriented fiber distribution. The quality of the web determines to a large extent the quality of the nonwoven fabric. Adhesive-bonded fabric manufacturing uses a wide range of natural and man-made fibers or their blends. Adhesion is achieved by means of the bonding agent, which may be an aqueous emulsion or a thermoplastic additive to the web. The adhesion of the bonding agent to the textile substrate must be good, and its cohesive strength must be adequate to withstand stresses during use. Because of the bonding action, the nonwoven fabric acquires strength and stiffness. The mechanical properties of fabrics (see to produce a nonwoven of this type with the weight range of 15 to 500 g/m 2 of either high flexibility but low strength or low flexibility but high strength. For increasing the drape properties and flexibility, the print bonding method is used. The spacing formed in this way between bonded areas allows freedom of movement of the fibers, which increases the fabric’s flexibility. Thermoplastic materials used for bonding web fibers are powders, fibers, yarns, nets, and films. Widely used in thermobonding technology are polyester fibers (including the hollow type), polyethylene, polya- mide, and special binder fibers. Most often, two-component fibers are used, formed from polymers with different melting temperatures. Thermoplastic materials in the form of bonding fibers are processed by a heat treatment (oven sintering or hot calendering). Thus, at a suitable temperature, the sheets of bicomponent fibers that are in contact in a web will remain bonded upon cooling. Nonwovens made in this way are characterized by a weight range of 15 to 80 g/m 2 and by good handle properties, porosity, and bulk. The portion of binder fibers to adhesive is 10 to 50%. The tensile strength of nonwovens is usually expressed in term of tenacity, as in the case of woven fabrics: Breaking force is determined on the base of a strip 50 mm wide. Therefore, the mass per unit length is expressed as mass of fabric strip 0.05 m wide and 1000 m length (tex). The tenacity of adhesive- and thermobonded fabrics is in range 1 to 4 cN/tex. 113.2.3.2 Spunbonded Fabrics The manufacture of spunbonded nonwoven fabrics consists of combining the preparation of webs with the production of man-made fibers. The whole sequence of operations, such as melt extruding and drawing of continuous filaments, arranging them on a moving collecting surface, forming a web, and bonding together by means of adhesive, thermobonding, or needlepunching, may be done in one process. Var ious man-made fibers may be used for the production of spunbonded nonwovens: viscose, polyester, nylon, polypropylene, polyethylene, and polyurethane fibers. The main spunbonded nonwoven properties depend on filament properties (linear density, tenacity, elongation, crimp, micromorphology), filament arrangement, and bonding parameters. These types of nonwoven fabrics are produced in weight range of 15 to 125 g/m 2 . The use of randomly arranged continuous filaments contributes to a higher tear and tensile strength (5 to 8 cN/tex) in all directions, and also to good handle (see Table 113.2). By use of modified spunbonding techniques, it is possible to obtain fabrics with special properties, including those required for coating products (greater elasticity, elongation, and air permeability). Tr ade names of spunbonded fabrics include Cerex (nylon 6 6), Reemay (polyester), Typar (polypro- pylene), and Tyvek (polyethylene). tenacity breaking force mass per unit length = DK4036_book.fm Page 10 Monday, April 25, 2005 12:18 PM © 2006 by Taylor & Francis Group, LLC Ta ble 113.2) depend highly on binder content, fiber type, and fiber orientation in the web. It is possible Textiles for Coating 113 -11 Melt-blown fabrics also belong to the class of spunbonded nonwovens. The production process differs from the spunbonded method with respect to the principle of fiber production. The polymer here is melt-extruded through a row of die openings into a stream of hot high velocity air. The filaments formed are broken into fibers, which are entangled to form a web. The melt-blown fabric differs from the spunbonded one in that the web contains staple fibers rather than continuous filaments, with diameters in the range of 2 to 5 µ m. This contributes to the softness, drapeability, opacity, and moderate strength of such fabrics. Strength may be increased by hot calendaring. The weight range of melt-blown fabrics is 60 to 500 g/m 2 . 113.2.3.3 Needlebonded (Needlepunched) Fabrics Needlebonded fabrics are manufactured by a mechanical method. The principle of needlepunched fabric production is realized when the fibers move from one face of a web toward the other face as a result of the penetrating of the web by many barbed needles. Because of the transfer of fibers made by the needles of the punching machine, the fibers are interlocked, and the web obtains stability and strength. If required, the fabric may be finished by adhesive bonding or pressing, steaming, dyeing, and calendering. The weight range of fabric is 200 to 1500 g/m 2 . The mechanical properties depend mainly on fiber charac- teristics, interfiber friction, web weight, and fabric finish treatment. Fibers of all types, and their blends, may be used for production of needlepunched fabrics. The strength of needlepunched fabrics varies in the range of 2 to 5 cN/tex. To increase fabric strength, additional backing in the form of a woven, knitted fabric or a film may be used. It is also possible to produce patterned colored fabrics by means of colored layers and by needling fibers from the top layer through the surface layer, making loops on the face of the fabric. Needlepunched fabrics with such special properties as flame retardancy, conductivity, and elasticity may be produced by using corresponding components. 113.2.3.4 Spunlaced Fabrics Spunlaced fabrics are made by entanglement of the fibers in the web by means of streams of high pressure water jets. The web obtains the required bonding, which influences the strength, handle, drape, and air permeability of fabrics, the fluid fiber entangled fabrics may be made in the weight range of 20 to 70 g/ m 2 and with a tenacity of 1.5 to 2.5 cN/tex. Polyester, polyamide, and other fibers may be used. 113.2.3.5 Stitchbonded Fabrics There are several techniques for producing stitchbonded fabrics. The stitchbonding of fibrous web carried out by Arachne (Czechoslovakia), Maliwatt (East Germany), and VP (USSR) is widely known. The web of natural or man-made fibers prepared by the carding process, with oriented or random arrangement of fibers, is stitched with yarns by means of warp knitting technology units. This technology is therefore sometimes known as “knitsew.” The type of stitch may be half-tricot, tricot, or others. The height of stitch varies from 1 to 6 mm. The gage of the VP machine is 2.5, 5, and 10; the gage of the Maliwatt varies from 3 to 22. Therefore, the number of courses in the fabric made varies from 5 to 25 (on a 50 mm base). The range of fabric weight is 160 to 400 g/m 2 for the VP and the Arachne, and 100 to 1600 g/m 2 for the Maliwatt. The mass of stitching yarns contributes 10 to 30% of whole fabric mass because the stitching system forms a continuous net of warp knit, filled with fibers of web. The mechanical properties of the fabrics produced by stitching a basic web depend on the type of fibers used as much as on the fabric stitching structure, causing friction between elements of fabric construction. The stitching yarns also contribute to fabric tenacity in the lengthwise direction. The tenacity of the fabrics considered is 1.6 to 3.5 cN/tex. The fabrics have good handle and tear resistance, pressing, or steaming. Because of their tensile strength, tear strength, and resistance to cyclic straining, webstitched fabrics are often used as backings for artificial leather, industrial coated fabrics, and other purposes. Stitchbonded fabrics made from yarns are produced using the Malimo (East Germany) technology. These fabrics are made with three sets of yarns. A warp system is fed from a warp beam. A set of weft DK4036_book.fm Page 11 Monday, April 25, 2005 12:18 PM © 2006 by Taylor & Francis Group, LLC especially in the cross direction (see Table 113.2). After stitching the fabric may be processed by dyeing, [...]...DK4 036 _book.fm Page 13 Monday, April 25, 2005 12:18 PM Textiles for Coating 1 13- 13 McConnell, R L., M F Meyer, F D Petke, W A Haile, “Polyester adhesives in nonwovens and other textile applications,” J Coated Fabrics, 16(1), 199–208 (19 87) “Vliesstoffe auf der Techtextil ’86,” Chemiefasern/Textilindustrile, 36 , 88, 581–5 87 (1986) © 2006 by Taylor & Francis Group, LLC DK4 036 _book.fm Page... • • Acid Yellow 17 Acid Yellow 23 Direct Yellow 11 Direct Yellow 86 Direct Yellow 1 07 Direct Yellow 1 27 Reactive Yellow 15 115-1 © 2006 by Taylor & Francis Group, LLC DK4 036 _book.fm Page 5 Monday, April 25, 2005 12:18 PM General Use of Inks and the Dyes Used to Make Them • • • • • • • • • • • • • • • • Marker inks Ballpoint inks Food Cleaners Cosmetics Drugs Wax Textiles Detergents Coatings Leak detection... polish © 2006 by Taylor & Francis Group, LLC 115-5 DK4 036 _book.fm Page 1 Monday, April 25, 2005 12:18 PM 116 Gravure Inks Sam Gilbert Sun Chemical Corporation 116.1 116.2 116 .3 116.4 116.5 116.6 Introduction 116-1 Process 116-2 Substrate 116-2 Vehicles 116-2 Colorants 116 -3 Formulations 116 -3 116.1 Introduction Gravure is a high-speed printing process... yarn wovens and knits 114-1 © 2006 by Taylor & Francis Group, LLC DK4 036 _book.fm Page 1 Monday, April 25, 2005 12:18 PM 115 General Use of Inks and the Dyes Used to Make Them Carol D Klein Spectra Colors Corp 115.1 115.2 115 .3 115.4 115.5 115.6 Ink-Jet Inks 115-1 Marker Inks for Children 115-2 Writing Inks 115 -3 Permanent Inks 115-4 Dyes Used in Permanent Ink Systems ... were thick, had poor tear strength when coated, tended to lint, were uneven, had comparatively rough surfaces, and had holes or voids where the yarns intersected — poor properties when very thin and even coatings were needed Initial nonwovens of the carded and random air-lay type composed of synthetic fibers were an improvement in some respects but not all Carded unidirectional webs were of good quality... Spunbonded Webs • Carded Unidirectional Webs • Carded, Cross-Lapped, Needlepunched Webs • Air-Lay Needlepunched Webs • Poromerics • Hydraulically Entangled Webs • Wet-Lay Mats • Stitchbonded Materials 114 .3 End-Use Applications 114-4 Albert G Hoyle Hoyle Associates Home Furnishings • Construction Uses • Automotive: Landau Tops, Interior Paneling, and Car Seats • Consumer Products • Filtration: Microporous... variation of the process using the same mechanics but not based solely on four-color work The substrate range is also much wider — including film and foil as well as paperboard and paper label Spot colors and coatings are often included In packaging, the ultimate printed product is a package, in which the printing not only decorates the product but may also serve a functional purpose, such as a barrier Product . Direction Cotton 5 7 4 7 4–8 16–24 Linen 6–8 5–6 5–21 5–8 Wo ol 2–5 1 3 20–28 28 33 Viscose 7 8 4–5 16–20 15– 23 Nylon 20–26 7 16 20–22 26–28 K d a dS=× = × y y yy 100 100 DK4 036 _book.fm Page 4. 1985. DK4 036 _book.fm Page 3 Monday, April 25, 2005 12:18 PM © 2006 by Taylor & Francis Group, LLC 1 13 -1 1 13 Textiles for Coating 1 13. 1 Yarns 1 13- 1 1 13. 2 Fabrics 1 13- 2 . ed., 1 970 ; 2nd ed., 1 976 ; 3rd ed., 1986. Osol, Arthur, Ed., Remington’s Pharmaceutical Sciences . Easton, PA: Mack Publishing Company, 14th ed., 1 970 ; 15th ed., 1 975 ; 16th ed., 1980; 17th ed.,