Textile Finishing

Spotting-Stains

D.Praveen Nagarajan

INTRODUCTION

Stain is a soil / spot / dust or any unwanted undesirable marks over the fabric it can be over the surface of the fabric, can be at interstitial sites or even inside the molecular structure of the fabric.

Stains can be prevented at various stages of production. This problem can be up to large extent at the initial stage itself.For this what we need is to take a little extra care and few precautionary measures at different stages as well as awareness among the operators and helpers they should be made to know the importance of quality in garment and should be trained to avoid quality related mistakes. If these measures are followed in the industry we can surely improve the quality and increase the already dipping profit margin at the same time we can fulfill our shipment commitments.

Soil / Stain removal is therefore an essential aspect of caring of fabrics if they are to be maintained in good condition.

Soil can be removed from fabrics by laundering or by dry cleaning.

Though the principle utilized in home laundering and professional are same, the equipment and cleaning products may vary.

Different stains

Protein: Blood glue, mud.

Tannin: Tea, coffee, ink, soft drink, turmeric.

Oil: Machine oil, Grease, Hair oil.

Dye: Ink, Felt tip pen, dye, paint

Combinational: Ball point pen, Tar, wax

Others: Rust, metallic.

Tannin Stain

Tannin stains are defined as any wet side stain originating from something that grows from the ground, e.g., vegetable.

This includes stains such as coffee, tea, juice, liquor, soft drinks, etc.

SOIL CLASSIFICATION

Soiling of fabrics occur as over all soiling, localized soiling (stains) or combination of two. The obvious effect of soil on a fabric is staining or dulling, stiffening, colour changing. Soils having similar characteristics are grouped together.

CLASSIFICATION OF STAINS BASED ON STRUCTURE

Classification of stain into three different categoriesSurface tensionInterstitial stainMolecular stain

Surface tension:This stain is classified depending on the type and the presence of stain in between the fiber. The stain is present at the surface of the fabric

Interstitial stain:Void created between the fiber.

Molecular stain:Reacts with the molecular structure of the fiber.

Their classification includes:

Solvent soluble soils (oil, grease, waxes)

Water solube soils – Partially / Completely (built up food stains, salts, sugars)

Insoluble soils (Carbon, dust, sand lint, oxidized oil stains) are removed by spotters.

Soluble Soils

Soluble dirt is made up of organic acids, alkaline substances, blood, starches and sugars. All these substances dissolve in cool or warm water and although they may some times require special stain removing techniques. These soluble substances are not serious problems to the cleaning process.

In-Soluble Soils

Insoluble soils may be held onto the fabrics by physical attraction or in film, greases or oils.

Such soil requires the use of detergents or other special laundry or cleaning products.

PROCESS OF CONDITION ANALYSIS

Before beginning the actual cleaning of a textile, an analysis must be made of the piece in question to decide whether to dry clean or to wet clean. Determinations must be made on

Generic type of fibres present must be identified, Textile Structure (Woven / Non-Woven),Type of colorants present (Natural dye / Synthetic dye), Kinds of soil / grease present (decide the cleaning method), Condition of textile material (strong / fragile), Medium of cleaning, Temperature required for cleaning Drying Facility

STAIN IDENTIFICATION

Of prime importance in stain removal is Identification of Stain. Common observations can be used to identify the stains present in garments.

Appearance of Spot or stains:

Color,Appearance, Shape, Observation under UV light, Odour – Perfume, Medicinal Stains, Location – Under arm (perspiration), food stains on tie Feel – Stiff, Sticky (glue type), rough or smooth (paint),

STAIN REMOVAL

Successful removal of stains from fabrics depends on the basic principle of not allowing the spot to stain to become set. A stain should be removed at the first possible opportunity because it may be more easily dissolved when fresh. The type of fabrics may limit selection of method to use in removing the stain will be determined by the type of stain and the type of stain remover.Use of an incorrect remover may damage or even destroy the fiber content of a fabric. Hot water should never be used on an unknown stain. The heat may set the stain, making it more difficult to remove.

STAIN REMOVAL TECHNIQUES

Sponging –

Place the stain face down on absorbent, clean, white paper towels or cloth. Apply the stain remover sparingly to the stain with a clean, soft, lintless cloth. Avoid circling and spreading the stain. Use light, brushing strokes, working from the outside of the stain toward the center. When the stain is removed, place the sponged area between layer of dry, absorbent towels to speed the drying process.

STAIN REMOVAL TECHNIQUES

Soaking –

Put the item in cool water unless the stain removal procedure you are following specifies warm or hot water. Soaking aids stain removal. Soaking time may vary depending on the type of stain. Avoid soaking some colored items for a long time to prevent damage to the color.

STAIN REMOVAL TECHNIQUES

Flushing –

Place clean absorbent materials under the stain, than add the stain remover in small amounts with a medicine dropper. Give fabric time to a soak in the fluid. Change the absorbent material as you flush out the stain. Rinse out the stain remover from the fabric with water.

KINDS OF STAIN REMOVERS

No single chemical can be used to remove all spots from the many different kinds of fibers. For example, since acids destroy cotton and linen, they cannot be used to remove stains from these fibers. Similarly, alkalies cannot be used on silk and wool. Acetate requires special care, as it dissolves in acetone, acetic acid, and chloroform.

WATER, ALKALIES AND ACIDS

Acids and alkalis should be used only as mild solutions.

When using a mild acid such as vinegar, any possible damage that might occur to the fabric must be counteracted by applying a weak alkali, such as a solution of bicarbonate of soda or ammonia water, to neutralize the acid.The fabric should be thoroughly rinsed in clear water.

If an alkali solution is necessary, it should be followed immediately with a mild acid solution (such as lemon juice, vinegar, or a dilute solution of acetic acid) to neutralize the action of the alkali.

The fabric should be well rinsed.

WATER, ALKALIES AND ACIDS

Many manmade fibers, such as the polyesters, acrylics, modacrylics & polypropylenes are not very absorbent, and fabrics of such fibers do not readily stain. Removal of stains for these fibers generally requires merely wiping with a damp cloth or washing with a mild soap in warm water.

BLEACHING AGENTS

Various bleaching chemicals are commonly used to remove stains. But such chemicals must be used carefully because they extract color and weaken the cloth.Household bleaches of chlorine solutions (sodium hypochlorite) should be used only on cottons linens, and rayon's – never on silk or wool. If a stain is to be removed with a bleaching chemical, the fabric should be stretched over a bowl of hot water and tied around the edges of the bowl.

BLEACHING AGENTS

The bleaching agent should be dropped on the stained area with a medicine dropper. This application must be followed immediately with a thorough rinsing. The entire procedure must be done quickly so that the bleaching agent will no remain too long on the material and cause undue weakening of the fabric.To prevent weakening, a few drops of oxalic acid or sodium thiosulfate (Photographer’s hypo) will neutralize the action of any chlorine bleach that may remain in the fabric. If a bleaching agent is used on a colored fabric, the dipping method is advisable to avoid unequal distribution of any subsequent loss of color.

Sodium-per-borate and oxalic acid

Sodium per borate and oxalic acid are effective in removing iron rust, metal stains, and some ink stains from all types of fabrics. These chemicals are the least harmful of all bleaches, but they must be used quickly to prevent abstraction of the dye.

For white woolens, sodium per borate is particularly effective and harmless.

For the removal of mildew, ink, iron rust, dye stains, a solution of one teaspoon of sodium hydrosulfite in a glass of water is one of the most effective bleaches. But the liquid must used be quickly and the fabric should be well rinsed. Otherwise, the color may destroyed and weakened the fabric.

Hydrogen peroxide

Hydrogen peroxide maybe used on all kinds of fabrics.

It is a mild bleach, but it can be made more effective by the addition of a little ammonia.

Oxalic acid and sodium hydrosulfite cannot be used on weighted silk.

SOLVENTS

Where a stain is known to be of a greasy nature, the use of a solvent alone is sufficient. Grease stains are easily removed by the following solvents:

Per-chloro-ethylene, Turpentine, Stoddard solvent, Gasoline, Ether, Acetone & Alcohol.

SOLVENTS

Even though water is the universal solvent and can be absorbed by almost all fibres, the increased weight and fibre size (swelling) can cause damage to the fibres. Water cannot always successfully remove oil borne stains, so other solvents are necessary.

Most dyes will not be affected by dry cleaning.

There are three dry cleaning solutions namely

Stoddard – petroleum based solvent

Per chloro ethylene – Chlorinated hydro carbon, typically used in commercial cleaners

Valclene A – Fluorinated hydro carbon from Dupont which can be applied without heating.

LAUNDERING

Laundering is based on the use of water as a solvent. Water is effective in dissolving or suspending particulate soils such as salts, clay, dust and water based spots and stains. The agitation is washing machine or rubbing often employed in hand washing provide mechanical action to loosen soil and stains. Higher water temperature usually enhance cleaning but may have detrimental effects on other properties like colour retention.

DETERGENTS

Detergents contain Surfactants, Anti-redepositing agents, Bleaches, Fluorescent Whiteners, Perfumes, and Processing aids to improve detergent power.

Detergents and Soaps surround the soil particles that are removed and suspend them in wash water preventing their re-deposition on the textile substrate.

They have a hydrophobic end that attracts oily substances, and an ionic end that attracts charged or hydrophilic substances. These substances form micelle, which are carried away when water is remove.

Recommended levels of detergents by the manufacturers indicated the level required to ensure critical micelle concentration.

DETERGENTS

Much soil is acidic in nature and will tend to neutralize some of alkalinity of the soap, therefore, heavily soiled garments require more detergents.

To ensure the presence of adequate alkalinity throughout washing, alkali boosters are added to increase the effectiveness.

DRY CLEANING AND DRY CLEANING SOLVENTS

Dry cleaning is called so because only minimum amount of water is used and because of the same reason. The fibers do not swell and also do not shrink as much. Organic solvents are used in textile cleaning when the conventional water-soluble cleaners do not dissolve certain type of stains. The most commonly encountered stains are varnishes, waxes, tars, cooking oils, fats, resins, and paints.

DRY CLEANING AND DRY CLEANING SOLVENTS

Petroleum based solvents are obtained from distillation by-products of crude oil processing. These solvents solubilize stains and become even more effective as a stain remover when “charged” i.e. combined with water and dry cleaning soap in small quantities. It is rarely used now days because of its flammability.

FACTORS AFFECTING SOIL REMOVAL

1. Type of soil,

2. Extent of soiling,

3. Age of soil and

4. Nature stained fabrics.

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Causes of Re-deposition

Re-deposition refers only to the fact that the fabric has darkened. When suspension power of detergents gets decreased, the occurrence of re-deposition increases. Other reasons are overloading the fabric, improper soaking, improper suds returning system

STAIN REMOVAL GUIDES

Asphalt, TarScrape excess from fabric with a dull knife. Sponge with dry-cleaning solvent.

Rinse with water, Apply detergent to stain. Launder, using hottest water for fabric. Use chlorine bleach if safe for fabric.

BEVERAGES (WINE, ALCOHOL AND SOFT DRINKS)

Sponge with cool water, Soak for 15 minutes in 1 qt. of lukewarm water,

½ tsp. liquid dish detergent and 1 tbsp. of white vinegar.

Launder.

If stain remains, soak in an enzyme

BLOOD

Soak in cold water for 30 minutes.

Wash with warm water and a detergent.

If stain remains, soak in an enzyme presoak and lukewarm water for 15 to 30 minutes or apply a few drops of hydrogen peroxide.

For old stains, apply a few drops of ammonia and wash with detergent.

CANDLE WAXScrape excess from fabric with a dull knife.Spray or sponge with dry-cleaning solvent, then rub with heavy-duty liquid detergent before washing. Pressing the wax between paper may set the candle dye more permanently by making it harder for the solvent to penetrate the wax. Launder using hot water and chlorine bleach if safe for fabric.

CHEWING GUM

Rub with ice cube and remove excess with a dull knife.

Sponge with dry-cleaning solvent or pre-wash stain remover and rinse with water.

Launder garment as usual.

CHOCOLATE OR COCOA

Sponge with dry-cleaning solvent or treat with pre-wash stain remover. Rinse.Apply liquid dish detergent to stain. Launder using hot water and chlorine bleach if safe for fabric. If stain remains, soak for 30 minutes in enzyme presoak. Rinse and launder.OR Bleach chocolate stains with hydrogen peroxide. Rinse with water and wash as usual

COFFEE, TEA

Soak in solution of 1qt. water, ½ tsp. liquid dish detergent and 1 Tbsp. vinegar for 15 minutes.

Rinse with water.

If stain remains, sponge with alcohol or soak in enzyme presoak and warm water for 30 minutes.

CREAM, MILK AND ICE CREAM

Sponge with dry-cleaning solvent, pre-wash stain remover or dry spotter (see recipe).

Allow to dry. Rinse with water.

Apply liquid dish detergent and launder in hottest water possible for fabric.

OR Soak in warm water and enzyme presoak for 15 to 30 minutes then launder.

DEODORANTS,ANTIPERSPIRANTS

Soak in cool water.

Apply detergent to stain and launder.

If fabric is discolored, treat fresh stains with ammonia and old stains with vinegar.

EGG

Soak in cool water with enzyme for 15-30 minutes.

Rinse and let dry.

Rub in detergent before laundering.

If greasy stain remains, apply pre-wash stain remover and launder.

FRUITS OR BERRIESSoak in 1qt warm water, 1 tsp. liquid dish detergent and 1 Tbsp. White vinegar for 15 minutes. Rinse.If stain remains, sponge with alcohol, rinse and launder.If color stain remains, launder using chlorine beach if safe for fabric or use oxygen bleach.

GRAVYSponge with dry-cleaning solvent or use pre-wash stain remover.Rinse with water. Air dry, then apply heavy-duty liquid detergent to stain and launder.OR Soak in warm water and enzyme presoak for 15 to 30 minutes. Launder.

GREASE, OIL AND BUTTER

Sponge with dry-cleaning solvent, then air dry.

Apply detergent to stain and launder.

OR use pre-wash stain remover and launder.

INK, BALL POINT, FELT TIP MARKERSponge on any of the following until stain is forced out: dry-cleaning solvent, alcohol, acetone or pre-wash stain remover. Let dry. Repeat if necessary. If any stain remains, apply heavy-duty liquid detergent and launder. Certain hair sprays are effective on ball point, but some may leave a gummy residue and perfume.

NAIL POLISH

Apply nail polish remover, amyl acetate or acetone to back of stain over absorbent material.

Do not use if fabric is acetate, triacetate or modacrylic.

Rinse and launder

PAINT, OIL BASERemove the paint before it dries. Sponge with dry-cleaning solvent.Rinse.If a thinner is recommended for the paint, treat stain with it. Work in liquid dish detergent and launder using hot water if safe for fabric.

PAINT, WATER BASE

Remove the paint before it dries. Sponge with dry spotter.

Soak stain in cool water.

Apply detergent and launder.

PENCIL MARKS

Use an art gum eraser to erase marks.

Sponge with dry-cleaning solvent or apply pre-wash stain remover Launder.

RUST

Apply a commercial rust remover.

Follow manufacturer’s directions.

Rinse before putting item in washer.

Use lemon juice and salt on stain.

Spread in the sun to dry.

Rinse launder.

SHOE POLISHSponge with dry-cleaning solvent or pre-wash stain remover.Rinse. Apply heavy-duty liquid detergent to stain and launder using hot water if safe for fabric. If stain remains, sponge with rubbing alcohol Rinse.

URINE, VOMIT AND MUCUS

Sponge or soak stain in cool water.

Apply detergent to stain.

Launder.

If stain remains, soak in an enzyme presoak for 30 minutes.

Launder using oxygen bleach.

Thank You