1.Introduction The laundry market is hardly the place one expects to see revolutionary change. For decades laundry detergents were typified by low-density synthetic powders containing a relatively limited number of ingredients, i.e., alkyl benzene sulfonate and alkyl sulfate surfactants, phosphate builders, sodium carbonate and silicate for alkalinity and machine protection, and sodium sulfate filler. The makeup of the market began to change in the mid-1960s when, under environmental pressure, the industry initiated a gradual transition from phosphate- to zeolite-based builder systems. Multiplication of product form began in the early 1970s with the introduction of liquid detergents. Yet through the mid-1980s the basic product forms with their high-volume dosages and bulky, giant-sized packaging remained largely unchanged. Beginning in the late 1980s, however, a revolution gripped the detergent industry with the introduction and rapid market expansion of compact powders. The revolution started in Japan in 1987 when the Kao Corporation introduced Attack, a compact high-density powder product. Within the first year of conversion compact powders captured 60% of the Japanese laundry market ultimately growing to over 90% [1]. By early 1989 compact powders began to appear in Europe and late that year they expanded into the United States [2]. From 1990 to 1994, compact, concentrated powders grew from 2% to over 90% of the powder market in the United States [3] (Fig. 1). Today compacts have largely supplanted the traditional low-density powder products in the United States, Europe, and Japan and are spreading to developing markets in Latin America, Eastern Europe, Asia, and the Pacific region. What exactly is a compact powder? Compared to traditional powders, compacts are characterized by 1. Higher bulk densities. Whereas traditional powders have bulk densities ranging from 200 to about 500 g/L, compact densities typically range from 600 to 900 g/L and higher, although there are some regional exceptions, e.g., the compact powders currently found in the Canadian market have densities on the order of 400 g/L. This generally results in the same amount of washing powder delivered in a much smaller volume of product. 2. Higher surfactant levels. Surfactant levels in low-density products usually do not exceed 20 wt%. Compact powders typically have surfactant levels of 25 wt% or more. 3. Lower dosages. In North America, recommended dosages for low-density powders range from 85 to 100 grams per wash load. Current compact dos- 12718-0002a.gif Fig. 1 Growth of compact detergents in the U.S. market from 1990 to 1994. ages range from about 60 to 90 grams per load. In terms of volume of product used per load, dosages in the United States have gone from 1 cup to 1/2 cup or less. In 1986, a typical European powder detergent dosage was ~200 grams per wash load. Today compacts with recommended dosages of ~70 grams per load are on the market. The move to compact powders has fueled significant change in both the process of detergent manufacture and the chemical technologies used in detergent formulation. Manufacturers are moving away from the standard spray tower operation that has been the hallmark of powder detergent production for almost 50 years. The demand for ever-increasing product densities has forced manufacturers to alternate processes like agglomeration. The drive to compaction has put formulation space at a premium requiring increased reliance on, and innovation of, space-efficient technologies like enzymes. The purpose of this book is to capture the trends in process and chemical technology that continue to drive compaction and densification of powder detergents. II. Historical Perspectives A. Detergent Formulation Prior to World War I, laundry products consisted principally of sodium- or potassium-neutralized fatty acid soaps. The first synthetic detergents, short chain alkyl naphthalene sulfonates, were produced in Germany during World War II as replacement for the then-scarce animal fats traditionally used in the production of soaps. Long chain alkyl aryl sulfonates were introduced as detergents in the 1930s and by 1945 had become the main surfactant component of synthetic laundry detergents [4]. The first built synthetic detergent, using sodium diphosphate as the builder, was introduced in the United States in 1947 [5]. The surfactants used in early synthetic detergents were prepared by reacting benzene with propylene tetramer to form the alkyl aryl group, which was then sulfonated. These materials, the so-called hard ABSs, were highly branched and nonbiodegradable. Over time they accumulated in the environment to such an extent that foaming resulted in some sewage treatment plants and waterways. In 1965 the U.S. detergent industry voluntarily withdrew hard ABSs from the market, replacing them with biodegradable linear chain analogs [5]. At the time of conversion to compacts the most widely used surfactants in synthetic powder detergents were the anionics; linear alkyl aryl sulfonates, or LASs, and long chain fatty alcohol sulfates, or ASs; and, to a lesser extent, long chain fatty acids, and the nonionic alkyl ethoxylates. In the mid-1960s, concern arose over the environmental fate of complex phosphates due to their implication in eutrophication of waterways. Since then, the detergent industry has devoted considerable energy to finding cost-effective replacements. The introduction of ion exchange materials, zeolites, as detergent builders in the mid-1970s led to a gradual movement away from phosphate technology. With the recent changes in formulation and manufacturing processes precipitated by the transition to compact detergents, the major U.S. manufacturers took the opportunity to formulate out of phosphate altogether. Importantly, this was achieved without compromising performance or consumer value. Today the conversion of the U.S. detergent market to nilphosphate formulas is virtually complete, 32% of European powders are zeolite-based [1], Canada is about 50% converted, whereas Latin America and many of the Pacific region geographies remain largely phosphate. However, the move to nil-phosphate builder systems increased the overall complexity of powdered detergents. In addition to binding hardness ions, phosphates provide a number of other functions that are critical to efficient soil removal and cleaning. These include soil peptization or breakup, soil dispersion, suspension, and pH buffering. Removing phosphate from detergent formulas required manufacturers to identify other actives that could fulfill its multifunctional role. Today nil-phosphate powders contain zeolites and/or layered silicates for hardness control, polycarboxylate polymers for soil suspension, citric acid for soil peptization and dispersion as well as pH control, and carbonate for calcium control and buffering. Table 1 shows a typical composition for the type of low-density, nil-phosphate powder product available on the market in the mid-1980s. B. Detergent Processing. The principal methods of producing low density powders are as follows [5]: Adsorption of liquid ingredients onto inorganic salts Dry mixing of dried concentrated surfactants with other powder ingredients Spray-drying Drum-drying By far, the spray-dry process is the most prevalent. In spray-drying detergent ingredients are mixed into an aqueous slurry and sprayed into the top of a 100-foot-high by 25-foot-diameter tower. Hot air (315400°C) is blown up the tower and the detergent droplets dry as they fall, producing dried granules at the bottom. This process typically results in powder products with densities in the range 200600 g/L. Spray-drying offers several advantages relative to the other methods available for production of low-density powders [5]: TABLE 1 Typical Formulations of Low-Density Heavy-Duty Granular Laundry Detergents Weight % in finished product Ingredient U.S. Europe Surfactants: Anionic (LAS/AS/AES) 1520 1015 Nonionic (AE) 03 05 Builders: Zeolite 2030 2025 Citrate 05 05 Polycarboxylate 03 04 Carbonate 812 515 Sodium silicates 13 46 Sodium sulfate 2025 925 Enzymes 02 02 FWA 0.10.5 0.10.5 Bleach: Perborate 15 Activator 03 FWA, fluorescent whitening agent. Produces light, fluffy powders with consumer-pleasing aesthetics Produces a dustless, free-flowing powder with little lumping or caking Produces particles with good solubility However, there are some constraints on the process that limit its application in the production of compact powders: 1. Highly heat-sensitive ingredients cannot be used. For example, ethoxylated surfactants generally cannot be spray-dried due to volatilization and recondensation of the unethoxylated alcohols in the tower resulting in high plume opacities [6]. 2. The process is only capable of making low- to medium-density products. A reasonable upper limit for the bulk density of a spray-dried powder is 600 g/L. While higher densities are attainable, they require suboptimized, inefficient formulations and process conditions to achieve acceptable particles. 3. High energy input is required resulting in a high cost of operation. The unique process requirements for manufacturing compact detergents with acceptable physical properties and performance are beyond the capability of modern spray tower operations. Conventional spray tower methods don't sufficiently reduce bulk density, requiring the use of posttower process like grinding and compaction to achieve target densities [7]. In recent years manufacturers have moved to alternative methods of particle production, like agglomeration, to make compact powders [8]. Product densities of 700 g/L or higher are now commonly available. The key advantage of this move has been an increase in formulation flexibility, allowing a broader range of ingredients, including heat-sensitive materials, and higher total active levels to be added to powder products. III. Conversion To Compact Powders Kao's introduction of a compact powder in 1987, followed by the rapid and total conversion of the Japanese market, was a prelude to the conversion of laundry markets in developed countries to compacts over the next 5 years. There are basically four key drivers behind the outstanding success and broad consumer appeal of compacts: 1. Convenience. Compact products are easier to carry, store, and use than the bulky, giant-sized boxes of conventional lowdensity powders. 2. Reduced environmental impact. Because they require less energy to distribute and use less total ingredients per wash load, compact detergents help to conserve resources. Additionally, the move to less energy intensive methods of powder manufacture have significantly reduced energy consumption [9]. The reduction in package sizes and the increasing use of recycled packaging material accompanying the move to compacts have had an overall positive impact on solid waste disposal and resource conservation. 3. Shelf space. Compacts offer retailers lower distribution, storage, shelving, and display costs [2]. 4. Performance. Most compact products offer better performance, with a broader range of benefits, at equal or lower price per use than traditional low-density products. Compacts rely on a greater use of surfactants, bleaching agents, enzymes, optical brighteners, zeolites, and layered silicate builders to achieve their end-result benefit. The smaller packaging and reduced dosages serve as a signal to the consumer of something new, different, and better than their traditional product. Delivering this superior performance while at the same time reducing dosage to the wash requires fundamental changes in product formulation including a move to higher actives, and a reduction in fillers and bulking agents. Because of these benefits, compacts have proven to be a business building proposition for most detergent manufacturers. In the United States alone compact powder detergents built business by 10% and achieved 90% conversion to compact among brands that offered both compact and low-density forms. IV. Impact of Compaction on Process and Chemical Technologies A. General Trends The conversion to compacts continues to drive significant technical development in detergent process and chemical technologies. This is reflected in the intense patent activity in these areas within the last few years. From 1992 to 1994 alone 1500 patents and applications were recorded for inventions directly relating to laundry detergents with the dominant focus on surfactant, bleach, and enzyme technology (Fig. 2). This unprecedented level of activity is driven largely by the need to continue improving wash performance with everdecreasing product dosages. With the current emphasis on globalization and the appearance of new processes for powder detergent production the major detergent manufacturers are looking for ways to introduce technologies globally. This is at least partly behind the drive for continued high levels of innovation in detergent processing and chemical technology. Table 2 highlights the diversity of water conditions, habits, and practices that must be considered when formulating common global products. In depth, thorough reviews of the major trends in process and chemical technologies accompanying the conversion to compacts are presented in subsequent chapters of this book. What follows is a brief overview of some of the most important changes. B. Process Technology Changes Sustaining a high level of cleaning performance in compact powders requires increased reliance on efficient, multifunctional ingredients formulated into high 12718-0007a.gif Fig. 2 Global laundry detergent patent activity from 1992 to 1994. TABLE 2 Comparison of Global Laundry Habits and Practices Feature U.S. Canada Europe Japan Latin America/Asia Pacific Type of wash Type of detergent Concentration (ppm) Powder Machine Machine Machine Machine Powder (64%) Powder (94%) Powder (80%) Powder (85%) Liquid (36%) Liquid (6%) Liquid (20%) Liquid (15%) Hand/machine-assisted hand Powder (100%) 1000 1500 5000 1000 25007500 Liquid 1550 1550 7300 730 Wash temp. (°C) Avg. 30 33 50 20 25 Range 2045 852 3090 1535 Water hardness (ppm) Avg. 100 140 200 50 200 Range 0250 0300 170300 0100 701000 Wash time/load (min) 12 12 55 10 10 active particles. To keep up with the volume limitations inherent in compacts, manufacturing processes are evolving away from spray-drying to particle-making processes like agglomeration, extrusion, and coating. The first generation of compacts to hit the market relied on existing production processes and achieved compaction primarily by use of deaerants and removal of sodium sulfate [10]. The second generation of compact powders utilized more complex production processes, like post tower densification through grinding and compaction to increase product density. Processes have been described in which low-density, highporosity, spray-dried granules are subsequently treated in order to increase bulk density [11]. The spray-dried granules are said to be brought into a deformable state by mixing in two sequential mixer/densifiers and treated to collapse the internal voids. This results in substantially reduced particle porosity and, in turn, increased bulk density. Bulk densities in excess of 900 g/L have been reported for both phosphate and nil-phosphate products. The second-generation compact products began to feature new chemical technologies as well. Lipase, an enzyme that catalyzes the hydrolysis of oily, insoluble, triglyceride soils like salad oil, cosmetics, and sebum, was introduced first in Japan in 1988, and subsequently in European compact powders in 1990 and U.S. products in 1991 [10,12]. The new generation of compacts is expected to move further away from traditional spray-drying by utilizing agglomeration, extrusion, and dry-mixing processes. These technologies rely on unique combinations of high-shear mixing to form dense particles. Typically, a high-active surfactant paste is mixed with a solid carrier like zeolite using high shear to form and build up particles into high-density agglomerates [13,14]. These new processes result in high-density particles with good flow characteristics and controllable rates of dissolution. Additionally, they tend to be less capital and energy intensive than traditional spray-drying while increasing formulation flexibility by allowing a wider choice of surfactants and other heat-labile ingredients. C. Chemical Technology Changes 1. Builders Probably the biggest change in product formulation accompanying the move to compacts has been in the builder system with the complete move away from phosphate builders. All compact powders in the U.S., European, and Japanese markets are nil-phosphate. Zeolites, polycarboxylate polymers, carbonate and silicate systems constitute the major builder components of today's products with citrate playing a minor role in some compact powders as a dispersion and solubility aid. The zeolites and some layered silicates serve a multifunctional role. Besides their inherent efficacy as builders, these materials are used as particle formation aids in compact processing. 2. Dispersants A key property of phosphate builders is their ability to disperse and suspend particulate soil. This is critical to achieving consumer acceptable end-result cleaning and whitening. Accordingly, as formulators moved away from phosphates this functionality had to be replaced. Today most compact powders rely on polymeric carboxylates to deliver particulate suspension, antiredeposition, and antiencrustation benefits. These materials typically take the form of homopolymers of acrylic acid or copolymers of acrylic and maleic acids. They work by adsorbing to soil particles thereby imparting a high degree of electrostatic and steric repulsion minimizing flocculation and deposition back onto fabric. These materials are widely used in laundry products today and are safe for the environment. Although they are not biodegradable, they are extensively removed from wastewater by adsorption to the sludge in sewage treatment facilities [15]. Recently, there have been a number of efforts directed toward the preparation of biodegradable dispersants [1618]. One class that has shown some promise are the polyamino acids. For example, condensation of aspartic acid in the presence of an appropriate catalyst is reported to yield a linear form of polyaspartic acid with good dispersancy properties and >90% biodegradation in semicontinuous activated sludge (SCAS)-CO2 testing [19]. Currently, however, these materials are cost prohibitive for large-scale use. Work continues with these and other classes of dispersants to identify high-performing, costeffective dispersants that are biodegradable. 3. Enzymes The move to compact powders has fueled advances in a number of technology areas. Nowhere is this more evident than in detergent enzymes. The ability to act catalytically, i.e., to cycle over and over during the wash, imparts a space efficiency to enzymes that is highly desirable to the formulator of compact powders. Because the enzyme is not consumed during the wash process, only small amounts are needed to deliver consumer-recognizable benefits. In a typical wash, enzyme concentrations of <1 ppm are required to deliver the desired effect. Since the introduction of compacts there has been a steady increase in the development and use of detergent enzymes as reflected in recent patent activity. In the 4 years prior to 1992, total detergent-related enzyme patent applications for both enzyme suppliers and detergent manufacturers numbered about 90. From 1992 to 1994, that number more than doubled. Figure 3 shows the patent activity relating to detergent enzymes for the major U.S., European, 12718-0011a.gif Fig. 3 Patent activity on detergent enzymes over the period 19921994. and Japanese detergent manufacturers and global enzyme suppliers over this 2-year period: Prior to the introduction of compacts the use of enzymes in detergents was limited primarily to one class of enzymethe proteases. Proteases catalyze the hydrolysis of protein-based soils like blood and grass. As shown in Fig. 4, most powder and liquid laundry detergents on the market today, both low density and compacts, employ a protease [20]. Recently, protein engineering has been used to construct detergent proteases with improved stability and performance characteristics [21,22]. In addition to proteases a limited number of brands also employ amylases. Detergent amylases catalyze hydrolysis of the a1,4 glucosidic linkages in starch. As such they show benefits on a number of common food soils like gravies, sauces, pastas, and baby foods. The use of amylase/protease combinations for improved stain removal and general cleaning was fairly well established in the mid-1980s and practiced in a number of European and U.S. brands. The use of these two enzyme types in compact powders is now fairly standard, especially in Europe. 12718-0011b.gif Fig. 4 Detergent protease usage across the major laundry markets. Advances in genetic and protein engineering have led to new classes of enzymes with novel benefits for use in compact products. In 1988, lipase appeared in one of the first compact powders to hit the Japanese marketLion's Hi-Top. Since then lipase has found broad application in the global detergent market. Second-generation lipases with improved cleaning efficiency are just now showing up in the compact detergent market [11,23]. In 1993, Procter & Gamble introduced NovoNordisk's Carezyme, a cellulase enzyme that helps keep cotton and cotton blends looking newer longer [24]. Carezyme is reported to extend the useful wear life of cotton garments by removal of pill and fuzz buildup that makes these items look worn and faded. Net, today's compact powders are relying more and more on enzyme technologies to deliver new cleaning and fabric care benefits. Products containing up to four different enzymesprotease, amylase, lipase, and cellulaseare now on the market [7,25]. The patent literature suggests that even more novel detergent enzymes are on the way. Enzymes that deliver antimicrobial activity [26], fugitive dye bleaching [11,27], and stain bleaching [28] have been reported as have enzymes with enhanced specificity toward body soil substrates like keratin [29]. 4. Surfactants. The linear alkyl benzene sulfonates, alkyl sulfates, and alkyl ethoxy sulfates continue to be the workhorse surfactants for compact powders. However, the introduction of new, low-temperature production processes has led to an increase in the use levels of alkyl ethoxylate nonionics. There has also been growing interest in employing surfactants derived from natural, renewable resources. Accordingly, alkyl polyglucosides, alkyl glucosamides, and methyl ester sulfonates are being developed and introduced into next-generation compact powders [30,31]. In addition, the new manufacturing processes implemented to achieve high-density particles require new delivery forms for the surfactants. High-active, high-viscosity surfactant pastes are needed for agglomeration and solid surfactant particles are needed for dry blending [32]. 5. Bleaches The global trend towards cooler washing temperatures has fueled the growth of bleach containing detergents as manufacturers strive to enhance cleaning performance under the kinetic and thermodynamic constraints of a cold water wash. Long the dominant product form in Europe, the detergent-with-bleach share of the U.S. market grew from 3.5% in 1986 to 10.9% in 1993 [33]. Two basic technology approaches have been taken to support these productsperoxide bleaches and activated peroxide systems. Peroxide bleaching relies on the generation of hydrogen peroxide from a precursor molecule during the wash process. Perborate monohydrate is the peroxide precursor preferred by the industry owing to its high rate of solubility and percentage of active oxygen (16% versus 10.4% for the tetrahydrate analog) [5]. Upon dissolution in water perborate monohydrate hydrolyzes to give hydrogen peroxide and sodium metaborate: 12718-0013a.gif Subsequent deprotonation of the hydrogen peroxide generates the bleaching species, perhydroxyl anion. This process is highly pH-dependent requiring relatively high alkaline conditions (pH >9) to achieve the perhydroxyl ion concentrations necessary for good bleaching. Additionally, it is well known that peroxide alone is an ineffective bleach below 60°C. Thus, for good bleach performance in cold water, many detergent manufacturers rely on activators to transform the peroxide into a more effective peracid bleach. A bleach activator is a molecule that reacts with the perhydroxyl anion to form a peracid bleach in the wash. The two most common activators used today are N'N'-tetraacetyl ethylene diamine (TAED) and nonanoyloxybenzene sulfonate (NOBS). In the wash TAED undergoes a perhydrolysis reaction with the perhydroxyl anion from peroxide to generate peracetic acid. NOBS reacts in much the same way but generates the more hydrophobic pernonanoic acid. Key features of the activator approach are efficacy and functionality. The peracid anions are much more effective bleaching agents at low temperatures than the perhydroxyl ion. Functionality, i.e., hydrophobic-hydrophilic balance, can be added to the peracid in order to improve performance on key consumer-relevant soils and stains. 6. Soil Release Polymers Soil release, by modifying fabric surfaces with materials that alter their polarity thereby decreasing adherence of soil, has been practiced for years by the textile industry. However, delivery of soil release agents through powder laundry detergents has only recently been practiced and the technical challenges are significant. Problems associated with the use of soil release agents in compact powders include limited water solubility of typical polymeric soil release agents resulting in inefficient deposition and poor performance; interference with particulate soil removalthe polymeric soil release agents tend to act as flocculants; and stabilityexcess water adsorption by the powder matrix can result in hydrolytic stability issues and/or recrystallization of the polymer agents to an insoluble form. The soil release agents most commonly used in compact powders are derivatives of two general polymer structures, cellulose and polyester-polyether block copolymers. Methyl and hydroxyalkyl derivatives are the most commonly used cellulosic soil release agents. They tend to have low interaction with surfactant systems, making them broadly applicable across a range of detergent formu lations. However, the cellulosic polymers are not highly surface-active, requiring relatively high molecular weights for efficient deposition onto fabric. The polyester-polyether block copolymers offer a high degree of structural flexibility through capping and control of the extent of condensation. This flexibility allows for some tailoring of the molecule for optimum performance in a given detergent composition. Nonionic [34], anionic [35], and cationic [36] derivatives have been reported. 7. Other Actives (a) Dye Transfer Inhibitors. A market segment that has grown with the introduction of compact powders is the color-safe detergent segment. These products have been introduced in North America, Europe, Latin America, and Japan [2]. They are formulated specifically for use with colored garments, providing both cleaning and improved color fidelity by reducing fading and dye transfer. The color care technology most frequently used in these products is a polymer, typically polyvinyl pyrrolidone, that acts as a dispersant for certain dyes, keeping them suspended in solution and thereby inhibiting their deposition back onto fabrics [37]. Inhibition of fugitive dye transfer reduces dulling and fading of colors after repetitive washing and improves the appearance of white items. (b) Fabric-Whitening Agents. The appearance of white garments changes as they age due, at least in part, to soil buildup and mechanical/environmental wear and tear. This aging process results in a loss of reflectance giving the garments a dull, gray or yellow appearance. The purpose of a fluorescent whitening agent (FWA) is to whiten fabric and maintain the original appearance of white items. The FWA compensates for the low reflectance of aged garments by adsorbing UV light and emitting it, via fluorescence, in the violet-blue region of the visible spectrum, resulting in an improved perception of whiteness and brighteness. Most of the FWAs used in laundry detergents are bistriazinyl derivatives of 4,4'-diaminostilbene-2,2'-disulfonic acid: 12718-0014a.gif where R and R' are substituted or unsubstituted amino groups, substituted hydroxyl groups, etc. [38]. The move to high-density compacts has three major implications for FWAs: appearance of the bulk detergent, dispersion in the wash, and chemical stability [39]. A benefit of using FWAs in powder detergents is the consumer-preferred whiteness they impart to the product itself. In order to achieve this the FWA must be homogeneously distributed throughout the product. The new process routes being used to manufacture compacts require that the FWA be supplied in a highly processable formusually as an aqueous slurry/dispersion or a fine powder. Uniform dispersion and exhaustion onto fabric are required for maximum FWA benefit. Any change in the detergent formulation or wash process that impacts particle solubility can lead to deposition of undissolved detergent granules on fabrics. If the FWA in these particles exhausts locally to the fabric rather than dispersing throughout the wash, consumernoticeable staining will result. Accordingly, a brightener with good dispersability is required for optimal fabric whiteness. Typically, this is achieved by addition of solubilizing moieties, like the sulfate group, to the FWA molecule. Chemical stability assumes greater importance in compact powders than in traditional low-density products owing to the higher density and hence the greater intimacy of the FWA with detergent ingredients like carbonate, silicate, and bleach. FWA stability is a function of the inherent electronic properties of the molecule as well as its solubility in the detergent formulation [39]. FWAs based on the dibenzofuranylbiphenyl structure have recently been reported [40]. These materials show low reactivity with detergent components like bleach and have lower water solubility than traditional FWAs. As a result, they exhibit excellent storage stability in bleach-containing compact powders (see figure 6 in Ref. 39). D. Compact Powder Compositions The new process and chemical technologies described in preceding sections are being used, to varying degrees, by detergent manufacturers to produce today's compact powder detergents. Table 3 shows the composition of typical highdensity compact powders currently found in various markets. V. Future Trends The pace of change experienced by the powder detergent market over the last several years is expected to continue with an emphasis on improving value and product performance. Manufacturers will be looking to deliver new benefits at little or no extra cost to the consumer. There will be a greater emphasis on novel detergent chemistries to deliver superior performance requiring a high TABLE 3 Typical Compositions of High-Density Compact Heavy-Duty Granular Laundry Detergents Weight % in finished product Ingredient U.S. Europe Japan Surfactants: Anionic (LAS/AS/AES) 2025 1015 2030 Nonionic (AE) 05 08 510 Builders: Zeolite 2530 2530 2025 Citrate 03 04 03 Polycarboxylate 03 05 03 Carbonate 1025 1520 530 Sodium silicates 13 520 315 Sodium sulfate Enzymes FWA Bleach: Perborate 1015 03 0.10.5 15 03 0.10.5 13 03 0.10.5 05 13 03 Activator 05 37 05 Abbreviation as in Table 1. degree of flexibility and adaptability in compact powder manufacturing processes. All elements of the detergent formulation will be subject to continual improvement. Future trends in compact powder formulation will include the use of low-foaming, cold water-soluble surfactants and an increased use of enzyme, polymer, and activated bleach technology. Two important trends that are expected to have a major impact on future detergent formulations are the continued move to cooler wash temperatures and fundamental changes in washing machine design. In the United States, there has been a slow but steady decline in wash temperatures since the early 1980s [33]. This trend has been matched in Europe where more loads are being washed at 40°C. Asia and Latin America have historically been cold water wash geographies. In order to deliver consumer-valued benefits under these conditions, focus will be directed to those chemistries and manufacturing processes that give readily soluble particles in cold water. The use of biodegradable branched chain surfactants is expected to increase because these materials reduce crystallinity in the finished particle promoting low-temperature dissolution [41]. A greater reliance on activated bleach technology, polymer, and proteinengineered enzymes with improved kinetics at low temperatures is expected given the already demonstrated value of these technologies in cold water laundering. In response to anticipated legislation on energy consumption. U.S. washing machines will become more energy-efficient, using less water and working at lower temperatures. It's not yet clear as to whether these machines will be horizontal or vertical axis. What is clear is they will require less water per load. The net effect will be a much higher ratio of fabric/soil to wash liquor. The new machine designs will likely require changes in compact powder formulations for improved solubility, foam control, rinsing, and cleaning performance. Lower foaming, more easily rinsable surfactants may be required due to increased agitation. Likewise, improvements in builder and dispersant technology are anticipated. Consumers will still want to wash large fabric loads in roughly one fourth of the volume of water, putting significant stress on the soil suspension system of the detergent [42]. Finally, environmental issues will continue to drive change in the entire detergent industry. Manufacturers will look for more cost-effective ways to further reduce the environmental impact of their products and packaging. Concerns over the compatibility of detergent products and the environment will continue to make biodegradable surfactants a requirement. Additional compaction is likely combined with the use of more weight-efficient ingredients (i.e., enzymes) in order to do more with less. Products will be packaged in recyclable, reusable, and refillable packages to minimize solid waste disposal. Already in Europe, North America, and Japan refill packages for compact detergents and fabric conditioners are being marketed. 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