Comparison of Cleaning Treatments for Conservation and Restoration of Cotton, Wool and Silk Fabrics

Cleaning ensures sanitization and thus the safety of the artefact itself and others stored/displayed in its vicinity. At the same time, the process invariably alters the character of textile to a certain extent. Cleaning ensures removal/deactivation of soil and harmful organic matter from the artefact. However, a small number of surface molecules from the textile might be eroded in the process as well. This leads to weakening of the textile and might cause alteration in colour spectrum/ depth etc. Controlled cleaning techniques in conservation laboratories focus on minimizing this damage. However, not much scientific data is available on the efficacy of present cleaning techniques employed in conservation laboratories. Presently aqueous cleaning and solvent cleaning are primary modes utilised as next step to dry tools. Additionally, novel cleaning technologies like enzyme wash and ultrasonic wash provide soil specific methodology that would reduce the threat to the base fabric. This article Knitting fair introduces to you.

The present paper is a systematic analysis of these cleaning techniques and their impact on aged museum fabrics, i.e., cotton, wool and silk. Change in tensile strength parameters, whiteness index and yellowness index have been used as indicators to test the efficacy of different cleaning techniques on aged museum textiles. Numerical data generated by laboratory experiments clearly indicate that there is no standard cleaning treatment available for the three natural fibres. Each fibre has exhibited suitability to different cleaning treatment while balancing between restored whiteness and minimizing strength loss.

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METHODOLOGY

Cotton, wool and silk samples were selected for research. The samples were tested for determination of tensile strength and Whiteness Index and yellowness index. Samples were subjected to accelerated ageing as per the method suggested in the AATCC Test Method 26-1994. This ascertained that samples were brought to a condition of approximately 20years of ageing. Aged Cotton, Wool and Silk samples were taken for Tensile Strength testing and Spectroscopy. Standard testing procedures were followed to measure the indicators. Thereafter, the aforesaid samples were divided into 4 groups for wet cleaning i.e., home laundry, enzymatic cleaning, dry cleaning and ultrasonic cleaning. The samples were subjected to treatments as appropriate for their fibre content. For example in the home laundry group cotton was exposed to the detergent, temperature and conditions prescribed for selected fabrics. After wet treatment, the samples were again tested for loss in tensile strength and removal of yellowness. Recorded values for whiteness Index and tensile strength were then compared to determine the best possible method.

A Home Laundry

Home laundry techniques are probably the oldest and simplest means of sanitizing fabrics. The primary merit of this method is that the worker gets to closely interact with fabric at every stage of treatment. This ensures the possibility of simultaneous improvisation, while the fabric is still under treatment. A crucial advantage of this technique stands that professionals can modify the procedure as per suitability to the textile while retaining absolute control over the artefact at the same time. For the purpose of this study AATCC test method 61-2007 was followed. Test no 1A- was used as specimens subjected to this test should show colour change similar to that produced by five typical careful hand launderings at a temperature of 40+/-30C. Laundering machine was adjusted to maintain the designated bath temperature of 40+/-20C. The wash liquor was prepared with total liquor volume of 200ml and detergent concentration at 0.37%. The test was run in lever lock stainless steel canisters of size 75X125 mm with 10 steel balls in each canister. The laundering machine was run for 45mins after which each test specimen was rinsed in a separate beaker. Each specimen was rinsed three times in distilled water at 40+/-20C with occasional stirring and hand squeezing. To remove excess water, flat specimens were pressed between folds of blotting paper. Thereafter, specimens were air-dried, placed flat on a blotting paper. A commercial detergent was used for cotton fabrics whereas a neutral soap was used as ‘non-ionic’ detergent for wool and silk.

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Dry Cleaning/ Solvent Cleaning

A synonym of solvent cleaning, this technique has been widely used for cleaning of sensitive textiles like wool, silk, chiffons. Most sensitive fabrics that behave adversely to aqueous medium stand comfortable to dry cleaning. For the purpose of this research AATCC test method, 158-1995 was used where samples were dry-cleaned at a commercial workshop with perchloroethylene. Drycleaning machine with a commercial rotating cage was used. The sample fabric was placed in the machine and perchloroethylene was introduced. The machine was run for the specified period of time. The solvent was thereafter drained and centrifuged. The load was dried in a drying tumbler by circulating in warm air for an appropriate time. The specimens were removed from machine immediately and placed on a flat surface for drying.

Enzymatic Cleaning

Literature about the use of enzymes is available from the late ’60s. In 1988, Segal published a paper reporting important factors affecting enzyme activity and various immersion and non-immersion techniques of application. Contemporary studies have repeatedly noted the efficiency of Cellulase enzyme as an effective bio-polishing agent for cotton fabric which considerably preserves the strength and weight parameters of the fabric in contrast to other chemical techniques (Bhat, 2000). The primary advantage of using enzymes is that enzymes are substrate-specific. Thus if proven useful, they stand superior to all parallel techniques of achieving a desirable result. The concept utilized in this section of the study is that of bio-polishing. The phenomenon talks about removing the damaged superficial layer of the fabric and restoring the fresher subsequent layers (Doshi et. al, 2001). Since the fabrics used in this section of the research were both cellulosic and protein in nature Cellulases and Proteases were the enzymes used for the purpose.

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Ultrasonic Cleaning

The potential of ultrasonic cleaning in conservation has been recognized for some time. Barton et. al. (1986), reported that archaeological conservation in Europe has resorted to this type of cleaning in dealing with waterlogged wood, textiles and leather artefacts. The principle of ultrasonic cleaning is the generation of mechanical impulses through a liquid at high frequencies. These impulses create minute bubbles of vacuum which implode against the immersed object, creating shocks which clean its surface (Dallas, 1976). Thus ultrasonic cleaning technique is effective while remaining gentle in terms of time and handle. Therefore the possibility of using ultrasonic cleaning technique for removal of a superficial damaged layer of aged fabrics was explored to restore whiteness without considerable strength loss. For the purpose of the present study, samples were cleaned in ultrasonic cleaning machine at North India Textile Research Association, Ghaziabad (Figure 1). Three cotton samples were washed at a temperature of 50oC with a commercial detergent at a concentration of 5gpl (IS: 5785: 2005). The first sample was taken out of the machine after 5mins, second after 8mins and third after 11mins (Sethi, 2012). The samples were then dried on a flat surface. Whiteness Index and tensile strength of these samples were recorded thereafter. Similarly, silk and wool samples were treated at a temperature of 40oC with a non-ionic washing detergent at 5gpl. Again the samples were dried flat and values for Whiteness Index and Tensile Strength noted thereafter. Thus the samples in all three fibres were subjected to the above-mentioned cleaning treatments. Whiteness Index and tensile properties for these samples were noted before and after the cleaning treatments. Comparison of these values provided insight into the utility of these treatments for each fibre.

For more knitwear knowledge, please pay attention to the knitting fair.

Source: textiles school

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There are many elements in addition to colors and patterns that you need to consider to buy the best fabric. This article Knitting fair introduces to you.

When buying fabrics, you want the very best but sometimes the choices are many and it can feel a little confusing when you are in a textile showroom. The first thing that will, of course, attract you will be the color and patterns of the fabrics on display. However, that is only one element of the fabric by the yard, there are many other elements that you need to consider for you to buy the best fabric. Some of the things you must look out for when buying fabrics are as follows:

Quality of the fabric

Before you even check whether it’s linen, cotton, polyester or nylon, you must feel it against your skin and feel whether it is of good quality. The fabric must be blemish-free especially when it comes to things such as dye, print, fibers, tears and so on. The quality should be perfect because if the fabric has blemishes, you will no doubt have clothes made that will depict those imperfections in the fabric.

Type of Fabric

Fabrics are mainly categorized as natural, synthetic or a blend of both. Good examples of natural fabrics are Cotton, Linen, denim, leather, silk. Synthetic fabrics are such as Polyester, rayon, spandex, DTY fabric, Acrylic, Nylon and so on. Fabrics with a blend of natural and synthetic fibers are also perfect for making clothes as long as they are in perfect condition. So, ask yourself whether you want to buy natural, synthetic or fabrics that are a blend of both. Natural fabrics tend to cost more compared to synthetic ones so your budget here will also have a role to play.

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Color Fastness

As you check your fabric out, make sure that the color is even minus any spots or streaks. Closely scrutinize the fabric and note any signs of uneven dyeing. If you happen to notice any areas with colors fading especially on the fold line you should move on to another fabric. When you see light colors in some parts of the fabric, unless it is a design of the fabric, don’t buy it because that is a sign that the color will fade when you wash the fabric. If you have to test it then use a white handkerchief or cotton ball which you have dampened and then rub it on a small part on the fabric, if the color appears on the kerchief or cotton then the fabric is not of good quality.

Suitability and Location

You probably have some sort of garment in mind when buying the fabric and you have to know the suitability of the fabric then. For example, you cannot make wool swimsuit or cotton sports clothes or polyester baby clothes. Think of the occasion and the place where the garments will be worn as you choose the fabrics to make them. Wool will not do in a desert environment and chiffon will definitely not be right for visiting the cold alpine region. The cotton fabric would be perfect for summer clothes since they are perfect for cooling the skin.

Shrinkage

You have to consider the shrinkage factor when choosing your fabric. You have to know if the fabric will shrink after getting washed. Every fabric shrinks differently. In order to be on the safe side, by an extra 10% of the fabric. If you can consider a preshrunk fabric which will not give you trouble. Preshrunk fabrics have labels such as “Sanforised”, “Mercerised” and so on.

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Color

The color of the fabric is very important especially if you are choosing the fabric to make your own dress. Choose a color that agrees with your skin tone to make the dress even more beautiful on you. If it’s a wedding color and you are buying fabric to make several dresses, just ensure that the color is in accordance with the `wedding theme color. Shop for the fabric in broad daylight and not after sunset if you are going to an actual brick and mortar shop. Artificial lighting can in some cases distort the color which is why you need natural light to tell the real color.

Just remember that once the fabric has been cut from the bolt, you cannot return it when you realize it’s the wrong color after buying it. It will not be accepted, and you will be forced to spend more on the right color of material this time around. This could really put a dent in your budget.

Pattern

You might be considering buying patterned fabric after you see the various appealing patterns on display. Just take into great consideration the fact that there will be pattern repeat in these fabrics which should influence the cutting. The motifs on the fabric have to be distributed in a systematic manner by being placed correctly especially at the seams. Be careful and ensure that the fabric doesn’t become distorted or when matched up or lined to create the garment. When it comes to patterns, choose one that will best represent the fashion look you intend to achieve with the dress created in the end.

The Fabric Grain

This should be a major consideration when buying fabrics because as much as you buy the most attractive fabric, it might present some challenges if the grain isn’t right. With the wrong grain on the fabric, the outfit you make with it will hang wrong. The moment you realize the grain of the fabric is all wrong don’t buy it to avoid further complications down the road.

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Fabric weight

The fabric weight is in most cases determined by factors such as the fiber type, weave and so on. The weight of the fabric can be indicated by GSM which can vary from 60-700. A denim fabric, for example, will have a GSM of 400 of course depending on the weave. Just remember that a higher fabric weight does not necessarily mean that the fabric is of fine quality. The fabric weight should mainly influence suitability. Knowing the fabric weight will help you compare various types of fabrics and decide on the best fabric for garments of certain occasions and environments.

Buying fabrics shouldn’t be a headache now that you know what to look for, thanks to the above list. Go out there and shop for the fabric of your dreams and transform it into the most fashionable designs of garments.

For more knitwear knowledge, please pay attention to the knitting fair.

Source: textiles school

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Higher quality yarn improves the weaving process. Introduction of very small non-film forming resin particles in conventional size formulations modify and provide improved fiber cohesion in the warp yarn bundle. This transient effect provides a more compact and improved yarn substrate to host conventional warp size polymers on the yarn surface. Evaluation of this technology in producing mills has provided positive results in all factors associated in the weaving process. This article Knitting fair introduces to you.

In the early 1800s, the introduction of the mechanical loom promised the potential of dramatically improved fabric production. However, the mechanical loom also introduced a level of abrasion on warp yarn that prevented this productivity potential. The abrasion problem was soon attacked by borrowing technology developed by the coatings industry. In coatings, surface protection was provided by the application of natural oils which crosslinked to form a permanent topical barrier. The concept provided the solution, but the woven fabric was not a candidate for a permanent abrasion barrier. Starch soon emerged as a suitable material to provide a transient abrasion-resistant barrier to protect warp yarn. This approach soon led to the development of the necessary machinery to apply an abrasion barrier and the concept was adopted by the industry.

During the next two centuries, significant improvements in coatings technology and materials have been adopted to accommodate continual changes in yarn composition, yarn formation, and loom technologies. Warp sizes are now designed to meet the demands of each fabric style on a case-by-case basis. Warp size suppliers and technicians have performed admirably in bridging continual changing technologies involved in the journey from fiber to fabric. We now are more secure in gauging general rules of viscosity, penetration and overall size add-on levels for optimum weaving performance. Optimization of the sizing formulation is now paired with the variables from the slasher through the greige fabric.

Advances in the use of polymer/starch surface barriers now dominate spun yarn sizing. Abrasion protection coupled with nearly 2 centuries of experience has achieved what is now regarded as the optimum in painting warp yarn. Unfortunately, this experience has fostered an attitude of complacency to the potential for improving weaving performance utilizing chemicals in the size box.

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The use of nanosize resins (oligomers) has now been evaluated as components in warp size formulations. On a theoretical basis, and the barrier coatings approach, these materials provide little optimism for improvements in weaving. Chemically, oligomer resins have the basic properties of higher molecular weight polymers of the same chemistry but are much too low in molecular weight for viable film formation. Minor adhesion and plasticization of conventional barrier film formers became the primary hope for this new technology. Initial trials with nanosize oligomers in conventional size formulations provided promising results in both adhesion and plasticization of the barrier coating. In addition, incorporation of oligomer resins provided differences that were not readily explained.

Reduction in both warp and filling stops.

Fiber and size shed at both the slasher and looms were dramatically reduced.

Increased yardage of hard yarn on the loom beam.

These results did not neatly fit into the barrier concept of warp sizing. Increased yardage on the loom beam logically indicated reduced size pick-up on warp yarn. However, multiple desize analysis of hard yarn from trials and normal production were equivalent. The repetition of these trials was consistent with the initial results. Nanosize oligomer resins were clearly providing a mechanism to complement barrier coating film abrasion resistance.

Microscopic (60X) photos were utilized to determine any visual differences between standard and trial hard yarns. Yarns containing oligomer resin in the size formulation exhibit a smoother surface with less hard fiber disruption from the sheet break. In addition, the examination of 60X photos of the sized yarn indicates a significant reduction in yarn core diameter. Sized yarn diameters exhibit near 20% reduction in comparison to normal formulation hard yarn at the same add-on.

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Examination of 1040X magnification cross-sections of yarn prior to the size box provides an explanation of the function of nanosize resins within the yarn bundle. Vacant spaces between fibers in the bundle are micron or greater in diameter and volume. Fibers in spun yarn systems are mildly anionic, natural or added, which maintain a repulsive force to keep fibers apart. As the yarn is wet-out by water, huge numbers of millimicron oligomer resin particles penetrate and adhere to fiber surfaces. Repulsive forces existing between fibers are overwhelmed and the fiber surface is modified with nanosize particles. These small resin molecules provide a like-like mutual attraction and allow fibers to be drawn closer together to partially reduce vacant spaces within the bundle. Immediate compaction of the yarn bundle occurs upon wet-out. A smaller yarn substrate is now available to host the barrier film. The count of the yarn remains constant with a smaller diameter bundle. An increase in the density of the yarn is attributed to improved fiber cohesion within the bundle.

Statamat and Uster evaluation of sized yarn at equivalent add-on provided revealing differences in properties of the sized yarns in both tensile and elongation. Although both Tensile & Elongation properties are affected, low-end values are the most important in weaving. Low-end properties are improved and the coefficient of variation reduced to provide a more uniform hard yarn. A particularly unusual benefit of fiber cohesion improvement has been in an average improvement in loss of elongation near 30% of conventionally sized yarn controls.

Years of experience with conventional size film formers have optimized penetration and encapsulation of the film barrier on yarn. Add-on levels and film locations are controlled by the viscosity of high molecular weight film formers to minimize penetration and maintain the size coating.

Adequate abrasion resistance from the barrier coating is dependent upon the surface area that must be protected. Sized yarn is a cylinder in which surface area is directly a function of the diameter of the cylinder. The new yarn created by nanosize oligomer resins in the formulation allows a reduced total size add-on to prevent oversizing and embrittlement of the hard yarn1.

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Oligomer resin effects on yarn are especially important in increasing low end tensile and elongation and reduction in coefficient of variation. This effect produces a more uniform yarn substrate for subsequent steps in the weaving process. Effects on yarn without warp size were determined through the addition of a small amount of oligomer product to the final rinse in a conventional mock dyeing procedure2.

Desize of greige fabric is accomplished utilizing conventional procedures at pH levels slightly above 7. For more knitwear knowledge, please pay attention to the knitting fair.

Source: textiles school

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