Clean Industrial Wash Recipes for Wet and Dry Processes for Denim, and Garments Produced by the Processes

This application is a non-provisional application of U.S. Provisional Application No. 63/659,579, filed Jun. 13, 2024, the complete disclosure of which is incorporated herein by reference and to which priority is claimed.

The present invention is directed to novel means to reduce and eliminate major problems associated with wet and dry processing of denim garments, such as jeans, namely the excessive number of processing steps to wash the jeans and the associated increase in water, energy, chemicals, carbon footprint and machine time and the use of harmful chemicals such as potassium permanganate in order to achieve the desired looks consumers demand. The embodiments include the use of a largely white core fabric, along with innovative laundry recipes disclosed in this application which allow for a reduction in the number of steps in the wet process, a significant reduction in water, chemicals, energy, carbon footprint and machine time, and the elimination of the use of potassium permanganate and dual laser processes. The embodiments generate unprecedented improvements in sustainability, with associated significant savings in water, chemicals, energy, carbon footprint, and/or most importantly time due to the easier washdown of the fabrics.

Denim garments, such as jeans, are made from denim fabric produced at the denim mill. The fabric is then sent to denim jeans manufacturers who cut and sew the denim fabric into rigid denim jeans. Then the denim jean manufacturers further convert the denim jeans to salable denim jeans for retail by the wet process laundry techniques and the dry processes of hand sanding, laser abrading, and potassium permanganate (PP) application. Since PP is a very toxic chemical, manufacturers have tried unsuccessfully for years to eliminate this step. However, the PP spray provides a very bright abrasion pattern that is very desirable in the marketplace to create a worn look on denim jeans. Some manufacturers actually have to laser the jean twice to get the bright abrasion achieved with PP and replace the same despite the marked cost increase with dual laser treatments. They will laser etch on the rigid garment, start the wash process, dry the garment, laser etch again, then finish the wash process. Laser boosters and other chemicals are attempted to replicate PP, but there is nothing in the industry that can successfully eliminate PP spray and all the steps that go with it. Some manufacturers apply the laser at an intermediate stage of washing, so they dry the garment before applying the laser. They wash the garment, then dry the garment, and then apply the laser, after which they again wash and dry the garment. The garment is thus dried twice, which consumes large amounts of energy.

Denim washing provides an aesthetic finish to denim fabric to enhance the appearance and to provide strength. The “wash down” and other “post-make” processes applied to denim garments are many and varied. Often the objective is to distress the garment so that it looks old and worn. This distressing gives the garments a “fashion” appeal and also softens an otherwise harsh fabric. The chemicals typically used in the washing process consist of several of the following:

There are a number of major problems associated with the use of such chemicals and the wet and dry processes used in the production of denim jeans. The current industrial laundry recipes are too lengthy and use more water, energy, chemicals, machine time, and labor time. The Los Angeles Times recently reported that “Water shortages are becoming a way of life in cities across the globe—Los Angeles; Cape Town, South Africa; Jakarta, Indonesia; and many more—as climate change worsens and authorities often pipe in water from ever-more-distant sources.” “Water sources are depleted around the world,” said Victoria Beard, a professor of city and regional planning at Cornell University. “Every year, more cities will face ‘Day Zero,’ with no water in their piped systems.” The Los Angeles Times further reports that “Mexico City—founded by the Aztecs on an island amid lakes, with a rainy season that brought torrents and flooding—might have been an exception. For decades, the focus has been on getting rid of water, not capturing it. But a grim convergence of factors—including runaway growth, official indifference, faulty infrastructure, rising temperatures, and reduced rainfall—have left this mega-city at a tipping point after years of mostly unheeded warnings. Distant reservoirs and underground wells are drying up as leaders belatedly confront an existential dilemma.”

Further, current industrial laundry recipes use harmful chemicals like PP to whiten the abrasion. Current industrial recipes sometimes use pumice stones, which is a non-sustainable process, where many repercussions to be faced like ETP sand powder collection, stone removals from individual garments 1 by 1 and its time-consuming, and also due to natural ferrous contamination, which is a challenge in metal detectors, etc. The current industrial recipes are very costly and time-consuming.

The inventors have determined through a series of innovative concepts that there is indeed a unique solution to this industry-wide problem, with such invention delivering unheard-of and substantial improvements in sustainability and cost savings for denim manufacturing. Significant reductions in water, electricity, harmful chemicals, energy, and carbon footprint are the unprecedented benefits of the inventors' invention in denim jean manufacturing.

The inventors have invented a technology to reduce the number of steps and eliminate processes in the denim jean wet process, with associated substantial reductions in water, chemicals, energy, carbon footprint, and production time. Embodiments detailed herein provide several examples of innovative recipes to reduce the number of wet process steps from about 16 steps for the conventional jean wet process to about 7 steps for the invention described here for a medium wash. Further, the inventors have shown that PP spray can be absolutely eliminated, and other tedious steps also eliminated to achieve the necessary brightness consumer's demand. The invention comprises two principal components to achieve significant sustainability improvements and cost reduction. The first component is to use denim fabric that has a relatively large white core in the yarn, such core at least 65% of the cross-sectional area of the yarn with the core exhibiting a whiteness that is more white than blue/black on the Commission Internationale De L'Elcairage (CIE) chromaticity scale. The second component to achieve the extraordinary results of reducing the number of wet process steps, possibly in half or more, is to employ the inventive recipes disclosed in this invention. The benefits of this invention are simply extraordinary and include:

1. The inventive recipes of this invention can be applied to all industrial laundries and can be leaned down to generate significant savings in water, energy, chemicals, carbon footprint, machine time, and importantly labor time.

2. Associated remarkable and unheard-of cost savings per denim garment as proven from numerous plant trials.

3. Hazardous chemicals like PP can be completely eliminated from the denim washing industry by introducing laser applications or manual hand-scrapping processes on the rigid garment through following the disclosures herein.

The pumice stone usage can be fully eliminated in inventive dyed fabrics by using stone-free enzymes as the fabric is giving faster panel abrasions.

The tables below illustrate the parameters for the conventional wash vs the invention washes for 100% sulfur black dye and indigo dye for each of the standard washes—light, medium, dark, and acid wash. The parameters include yarn size and color, water and chemical(s) used, steam, machine time, #hydro, dryer and dry process cycles, and use of Potassium Permanganate and stones in the washing bath. Hydro extraction is removal of water from the washed wet garments by mechanical methods. The wet process is a machine process where the wet garments are loaded into a machine that rotates very fast so that its centrifugal forces are created and to squeeze water from the garments. For each case, the percent savings, batch savings, and total savings realized from the inventive wash recipe vs the conventional wash recipe are shown.

TABLE I. Benefits of invention recipes vs. conventional recipes for 100% sulfur black dye and dark wash standard;

TABLE II. Benefits of invention recipes vs. conventional recipes for indigo dye and dark wash standard;

TABLE III. Benefits of invention recipes vs. conventional recipes for 100% sulfur black dye and medium wash standard;

TABLE IV. Benefits of invention recipes vs. conventional recipes for indigo dye and medium wash standard;

TABLE V. Benefits of invention recipes vs. conventional recipes for 100% sulfur black dye and light wash standard;

TABLE VI. Benefits of invention recipes vs. conventional recipes for indigo dye and dark wash standard;

TABLE VII. Benefits of invention recipes vs. conventional recipes for indigo medium wash standard with hand sanding;

TABLE VIII. Benefits of invention recipes vs. conventional recipes for 100% sulfur black hand sanded; and

TABLE IX. Benefits of invention recipes vs. conventional recipes for indigo dye acid wash standard.

The first component of the invention is to use denim fabric that has a relatively large white core in the yarn, such white core having at least 65% of the cross-sectional area of the yarn with the core exhibiting a whiteness that is more white than blue/black on the Commission Internationale De L'Elcairage (CIE) chromaticity scale. An exemplary description of such a yarn can be found in U.S. Pat. No. 10,508,388 entitled “Yarn Material with a White Center”, the complete disclosure of which is incorporated herein by reference.shows an example of a yarn with the characteristics of the white core, which include a bright whiteness associated with the core that is very large and at least 65% of the cross-sectional area of the yarn. One way to achieve these characteristics is with denim mill processes as disclosed in U.S. Pat. No. 10,508,388. However, other denim mill practices or chemical treatments may be appropriate to achieve similar white core characteristics, and the important first component of the invention is not the process to create the white core characteristic in denim but the use of the white core product with the defined characteristics in denim jean manufacturing.

One should note the stark contrast of white-core yarn required for the invention and yarn cores from conventional denim products. This is best illustrated by a comparison of, whereis a picture of the core of conventional denim yarn and clearly shows an off-white character and a relatively inconsistent core size. Yarn cores with these types of characteristics are not optimized for the invention and will not deliver the extraordinary sustainability and cost savings benefits shown for the invention.shows a relatively large core more white than blue/black and is representative of the type of core optimized for this invention.

The second component of the invention to achieve the extraordinary results disclosed is to use the innovative wet and dry process recipes detailed below. These recipes are examples of how the invention results in lean and reduced wash recipes. Regardless of the type of finish, the disclosed invention will always lead to a dramatic reduction in process steps and major sustainability savings. The invention recipes are shown for the following wash standards and denim dyes:

Detailed specifications for each case (three different denim dyed fabrics washed to different wash standards) are given inin the attachments.are specifications for the invention recipes on fabric with large white cores, andare the corresponding recipes for the standard conventional denim products with off white cores with diffused dye inside the cores of the yarn. The invention recipes are then compared to the conventional recipes to achieve the same standard in Tables I-IX where the remarkable sustainability advantages, environmental savings, and cost savings are shown.

The difference between dark, medium, and light wash standard is the base shade (in other words base color of the denim garment). The denim fabric at the unwashed stage is dark. When it is washed with different types of chemicals at different conditions like temperatures, Ph levels, water levels, dosages of chemicals, machine types, etc, it starts losing the dyes and starts becoming abraded (hi-low effect which is the common phenomena on denims) on the stitched edges. The base shade starts getting lighter as the wash aggression increases. The fabric can be controlled at different shade levels from dark to light during washing. The difference is not recognized as an industry standard because different fabrics come with different amounts of dye. A fabric with a higher amount of dye shows darker shades compared to less amount of dye. Every type of fabric can be washed from the existing shade level to lighter levels. The differences of standards in base shades are set by the brand people, mainly by designers as per their choices after analyzing market trends, sales strategies, seasonal aspects etc. These standards will be unique for the individual brands for specific season, fabric, wash type, etc and not common standards for all denims in whole industry.

Here the abraded garment means a garment with dry processes (whiskers, scrapping/blasting, PP sprayed one in terms of conventional wash. The inventors can achieve the same look by following steps: (1) Before washing the garment, (2) Place the garment under the laser, (3) apply the laser per the design set, (4) Turn off the laser, and (5) remove the garment, INVENTION RECIPE FOR 100% SULFUR BLACK DARK WASH SHOWN IN.

The first invention recipe for 100% sulfur black dye for the dark wash standard is found in the attached.details both the wet and dry processes and includes information on washing machine type, item type, washing machine time, water used, total chemicals used, dry process time, hydro time, dryer time, and detailed specifications including temperature, time and steam for enzyme wash, rinse, softener and hydro extraction. This type of detail is what the laundry needs to practice the dry and wet process part of the invention. As used herein, the following terms have the following meanings:

By examining the column titled Time (Min), five steps for the invention recipe for the 100% sulfur black dyed fabric are required to achieve the dark wash standard. This is quite favorably compared to 10 steps for the same case with the conventional wet processing to achieve the same dark wash standard in most laundries in the world shown in the attachedfor the 100% sulfur black dyed fabric and a dark wash. In both cases, the goal was to achieve the same aesthetic look for the dark wash standard. To get the same aesthetic look for the conventional dark wash for conventional fabrics and the invention recipe dark wash for the white core fabric, the invention recipe garments underwent just 5 steps in a wet process and further saved 1 complete hydro extraction and 1 drying cycle, while eliminating the potassium permanganate spraying process, manual hand sanding whisker and scrapping processes, PP neutralizing and rinse wash steps, as revealed in the comparison of the invention recipe shown inwith the conventional recipe shown inPotassium permanganate is typically used at the end of the wash process just before the tint and softening steps. The garment must be dried before PP application. Typically the garments are hydro extracted, dried, and then PP sprayed onto the garments.

The example wash comparison has been done with 100% Sulfur black conventionally dyed fabric washed with conventional wash recipes against the invention wash recipes on 100% sulfur dyed fabric with large white cores to achieve the same aesthetic and level of wash standard. The conventional wash recipe has dry processes, such as laser, manual hand sanding whiskers, manual scrapping and PP spraying on top of scrapped areas, plus wet processes including enzyme wash, PP neutralizing, and then softener.

In the conventional recipe of 100% sulfur black dark wash, manual hand sanding whisker, manual scrapping on front and back, and PP spraying are done on top of scrapping areas and also PP is sprayed there. The garment has to undergo an extra hydro and drying cycle compared to the invention recipe. And in the enzyme wash, faster abrasion is achieved in the invention recipe compared to the same on the conventional recipe.

In the invention recipe, the dry processes are achieved by laser abrading at the before-wash stage, where there is no need for two-time hydro and two-time drying. And also, an extra neutralizing process is needed in the conventional recipe.

The invention fabric has a largely white core in the yarn cross-section, and it has the ability to abrade the dyeing layer on the yarn cross-section easily. Hence, the whitish core appears on the surface in the case of the invention recipe. The same whiteness is very hard to achieve in the conventional fabric of 100% sulfur, even though PP spraying is done to get the required whiteness on the scrapped areas.

This significant improvement in the wet and dry processes for the invention recipe vs the conventional recipe for 100% sulfur black dyed fabric and the dark wash standard generates substantial sustainability advantages and large cost savings per denim jean. Indeed, and remarkably, the dramatic improvement can be clearly seen in Table 1, details of which follow:

As used in the footnotes, “Machine Time” is the treatment time of the garment in the washing machine, hydro extractor and dryer, “The Other Operation Time” means the time required to treat the garment for dry processes, such as laser abrading, manual hand sanding, PP spteay, etc. In the Example, total garment batch size is 200 garments, it takes 1 minute/garment, so total time is 200 minutes. 1.25 minutes/garment is required for manual hand sanding, so the total time is 250 minutes.

Comparisons of both recipes reveals the major savings achieved with the invention recipe over the conventional recipe as follows:

In the conventional recipe, additional wet processes have to be undertaken due to the nature of the fabrics, to get the white bright look of the dry processed areas with PP spraying. Hence there is an additional rinse wash and neutralizing process compared to the invention recipes. This along with PP spraying chemical preparing water together gives the water saving as such.

In the conventional recipe, neutralizing chemicals (sodium metabisulfite) must be used after PP spraying process to neutralize the PP chemicals in the sprayed areas, and then only it becomes a whitish color. And, the PP amount counted into additional chemical amounts to go up in conventional compared to invention recipes.

Major steam savings are achieved due to the additional drying cycle involved in conventional recipes due to PP spraying. Before PP spraying, the garment will first undergo a simple enzyme wash and then hydro extraction and drying the garment before preparing for the PP spraying. So, the garments will run around 60 minutes in the drying cycle, which uses maximum steam compared to the invention recipes.

In the wet process area mainly three machines are used. The washing machine, hydro extract machine, and drying machines. So, in the conventional recipe an additional rinse step, one neutral step, one hydro extract process, and one drying process additionally are required. This is because PP spraying processes are involved in the conventional wet processing recipes.

This machine time savings means a lot for a laundry, as the drying and extract capacities are going to go up by 50% and allow more drying and hydro extractions. The analysis in Table I shows an impressive machine time savings of 79 minutes for the invention recipe compared to the conventional recipe.

The dry processes are known as prior processes to the wet process and involve many laborers in the washing industry. The conventional washing requires that laundries are using many workers in dry processes, such as hand sanding whiskers, hand sanding scrapping and PP spraying, grinding, and tacking.

However, the latest technologies are being used to get the labor oriented dry processes to be replaced by laser. The laser is a process where it burns out or abrades the surface dye stuff and if need be the yarn itself per design requests for the garments. Two of the inventors of this invention actually invented, patented and licensed laser abrasion to major denim brands across the globe.

The wash recipe decides the final washed shade of the garment. The laser intensity is adjusted considering the type of fabric, type of wash, and required brightness. If the fabric has synthetic material in the weft, then the laser intensity should be reduced because high laser intensity may damage the synthetic component of the weft. The laser intensity is also set based on the wash. If the wash recipe is very aggressive and results in a relatively light shade, then the shade difference in between non-lasered areas and the lasered areas reduces; and to enhance the difference, the laser intensity is increased. As the laser intensity increases, the laser beam penetrates more into the fabric, resulting in more layer removal of the fabric surface. This may result in more brightness on lasered area on a washed garment. This is because the dye concentration is higher on the top layers and reduces in the inner layers of indigo and sulfur dyed yarn.

So, in the invention recipes, garments always do the dry processes before the wash stage with laser, and hence manualprocesses-manual whisker, manual scrapping and PP spraying, are replaced by one single process using a laser. The most beautiful aesthetic look can be obtained by adjusting and fine tuning the laser designs. In the cases where garment manufacturers do not have lasers or enough capacity of lasers, hand sanding alone on the rigid (unwashed) garment can also achieve the necessary brightness using this invention.

The necessary brightness is the brightness of the abrasion area of the denim garment that is aesthetically pleasing using this invention. Dry processes aesthetics are a set standard similar to those based on shade level. To achieve the specified levels, laser settings need to be tested, typically through trial and error, to match the same look what brands require. Once the aesthetics are achieved, the laser machine settings, mainly two parameters like DPI (dots per inch) and TPX (Time per pixel) are set for a particular wash and continue.

Here in this case, substantial process time is saved in the invention recipe as the labor oriented 3 processes takes a long time to complete. This recipe analysis shows 90 minutes of operation savings and in combination with the other time savings represents a considerable advantage in terms of productivity and additional throughput.

One would expect that all these savings for the invention recipes compared to the conventional recipes would generate substantial economic savings. Indeed, that is correct as Table I amazingly reveals a total savings per batch of $58.33 and a savings per garment of $0.29.