Fabric softener
Encyclopedia
Fabric softener is used to prevent static cling
and make fabric softer. It is available as a liquid, crystals and dryer sheets.
easier and/or make clothes dry faster. All liquid fabric softeners are designed to be added to water - either by adding the product directly to the final rinse water or by 2:1 (water:softener) dilution in an automatic dispenser. Even diluted fabric softener will cause spotting when poured directly onto clothes and can ruin them.
Dry fabric softeners typically come in the form of dryer sheets, which are added to clothing in the tumble dryer to soften the fabric and prevent build up of static electricity in susceptible fabrics. Many alternative uses of dryer sheets have been suggested by users such as dusting and removing hair from clothes.
Fabric softeners work by coating the surface of the cloth fibers with a thin layer of chemicals; these chemicals have lubricant
properties and are electrically conductive, thus making the fibers feel smoother and preventing buildup of static electricity. Other functions are improvements of iron glide during ironing, increased resistance to stains, and reduction of wrinkling and pilling.
Cationic softeners bind by electrostatic attraction to the negatively charged groups on the surface of the fibers and neutralize their charge; the long aliphatic chains are then oriented towards the outside of the fiber, imparting lubricity
. Vinegar
works on some materials in a similar way, as the hydrogen ions bind to the anionic groups on the fibers.
The disadvantage of coating fibers by hydrophobic layer is in decreasing the water absorption properties of the fabric, which may be undesirable in towels and diapers. Therefore the cationic softeners are often combined with other chemicals with lower affinity to the fibers. The use of fabric softener is contraindicated in some articles, such as microfibre textiles.
Most good quality all-cotton towels do not need to be treated with fabric softener and with repeated washings and dryings, they become softer naturally. Over time, towels that have been softened with fabric softener are less absorbent.
and olive oil
, corn oil
, or tallow
oil.
Contemporary fabric softeners tend to be based on quaternary ammonium
salts with one or two long alkyl chains, a typical compound being dipalmitoylethyl hydroxyethylmonium methosulfate. Other cationic compounds can be derived from imidazolium, substituted amine salts, or quaternary alkoxy ammonium salts. One of the most common compounds of the early formulations was dihydrogenated tallow dimethyl ammonium chloride (DHTDMAC).
Anionic softeners and antistatic agent
s can be, for example, salts of monoester
s and diesters of phosphoric acid
and the fatty alcohol
s. These are often used together with the conventional cationic softeners. Cationic softeners are incompatible with anionic surfactant
s used in the bulk of surfactants used in detergents, with which they form a solid precipitate. Therefore, they have to be added during the rinse cycle instead. Anionic softeners can be combined with anionic surfactants directly. Other anionic softeners can be based on smectite clays. Some compounds, such as ethoxylated
phosphate esters, have softening, anti-static, and surfactant properties.
The softening compounds differ in affinity to different materials. Some are better for cellulose
-based fibers, others have higher affinity to hydrophobic materials like nylon
, polyethylene terephthalate
, polyacrylonitrile
, etc.
Silicone
-based compounds such as polydimethylsiloxane
comprise the new softeners which work by lubricating the fibers. Derivatives with amine- or amide-containing functional groups are used as well. These groups help the softeners bind better to fabrics.
As the softeners themselves are often of hydrophobic nature, they are commonly occurring in the form of an emulsion
. In the early formulations, soap
s were used as emulsifiers. The emulsions are usually opaque, milky fluids. However there are also microemulsion
s where the droplets of the hydrophobic phase are substantially smaller. The advantage of microemulsions is in the increased ability of the smaller particles to penetrate into the fibers. A mixture of cationic and non-ionic surfactants is often used as an emulsifier. Another approach is using a polymeric network, an emulsion polymer.
Other compounds are included to provide additional functions; acids or bases for maintaining the optimal pH
for adsorption to the fabric, electrolytes, carriers (usually water, sometimes water-alcohol mixture), and others, eg. silicone-based anti-foaming agents, emulsion stabilizers, fragrances, and colors. A relatively recent form on the market are the ultra-concentrates, where the amount of carriers and some other chemicals is substantially lower and much smaller volumes are used.
In recent years, the importance of delivering perfume onto the clothes has possibly exceeded that of softening. The perfume levels in fabric softeners has gradually increased, requiring high-shear mixing
technology to be used to incorporate greater amounts of perfumes within the emulsions. Long term release of perfume on the fabric is a key technology now being utilized. Each country tends to have different perfume requirements and brands may have different softener/perfume ratio depending on the country.
Static cling
Static cling is the tendency for light objects to stick to other objects owing to static electricity. It is common in clothing, but occurs with other items, such as the tendency of dust to be attracted to, and stick to, plastic items....
and make fabric softer. It is available as a liquid, crystals and dryer sheets.
Varieties
Many modern washing machines have a dispenser which can add liquid fabric softener to the load of laundry automatically on the final rinse; in launderettes one may need to add it manually. Some brands of washing powder have fabric conditioning mixed in which is claimed to save money when compared to buying ordinary washing powder and fabric softener separately. Some manufacturers claim their products make ironingIroning
Ironing is the use of a heated tool to remove wrinkles from fabric. The heating is commonly done to a temperature of 180-220 °Celsius, depending on the fabric. Ironing works by loosening the bonds between the long-chain polymer molecules in the fibers of the material...
easier and/or make clothes dry faster. All liquid fabric softeners are designed to be added to water - either by adding the product directly to the final rinse water or by 2:1 (water:softener) dilution in an automatic dispenser. Even diluted fabric softener will cause spotting when poured directly onto clothes and can ruin them.
Dry fabric softeners typically come in the form of dryer sheets, which are added to clothing in the tumble dryer to soften the fabric and prevent build up of static electricity in susceptible fabrics. Many alternative uses of dryer sheets have been suggested by users such as dusting and removing hair from clothes.
Fabric softeners work by coating the surface of the cloth fibers with a thin layer of chemicals; these chemicals have lubricant
Lubricant
A lubricant is a substance introduced to reduce friction between moving surfaces. It may also have the function of transporting foreign particles and of distributing heat...
properties and are electrically conductive, thus making the fibers feel smoother and preventing buildup of static electricity. Other functions are improvements of iron glide during ironing, increased resistance to stains, and reduction of wrinkling and pilling.
Cationic softeners bind by electrostatic attraction to the negatively charged groups on the surface of the fibers and neutralize their charge; the long aliphatic chains are then oriented towards the outside of the fiber, imparting lubricity
Lubricity
Lubricity is the measure of the reduction in friction of a lubricant. The study of lubrication and mechanism wear is called tribology.-Measurement of lubricity:...
. Vinegar
Vinegar
Vinegar is a liquid substance consisting mainly of acetic acid and water, the acetic acid being produced through the fermentation of ethanol by acetic acid bacteria. Commercial vinegar is produced either by fast or slow fermentation processes. Slow methods generally are used with traditional...
works on some materials in a similar way, as the hydrogen ions bind to the anionic groups on the fibers.
The disadvantage of coating fibers by hydrophobic layer is in decreasing the water absorption properties of the fabric, which may be undesirable in towels and diapers. Therefore the cationic softeners are often combined with other chemicals with lower affinity to the fibers. The use of fabric softener is contraindicated in some articles, such as microfibre textiles.
Most good quality all-cotton towels do not need to be treated with fabric softener and with repeated washings and dryings, they become softer naturally. Over time, towels that have been softened with fabric softener are less absorbent.
Composition
The earliest fabric softeners were developed during early 20th century to counteract the harsh feel which the drying methods imparted to cotton. The cotton softeners were typically based on water emulsion of soapSoap
In chemistry, soap is a salt of a fatty acid.IUPAC. "" Compendium of Chemical Terminology, 2nd ed. . Compiled by A. D. McNaught and A. Wilkinson. Blackwell Scientific Publications, Oxford . XML on-line corrected version: created by M. Nic, J. Jirat, B. Kosata; updates compiled by A. Jenkins. ISBN...
and olive oil
Olive oil
Olive oil is an oil obtained from the olive , a traditional tree crop of the Mediterranean Basin. It is commonly used in cooking, cosmetics, pharmaceuticals, and soaps and as a fuel for traditional oil lamps...
, corn oil
Corn oil
Corn oil is oil extracted from the germ of corn . Its main use is in cooking, where its high smoke point makes refined corn oil a valuable frying oil. It is also a key ingredient in some margarines. Corn oil is generally less expensive than most other types of vegetable oils. One bushel of corn...
, or tallow
Tallow
Tallow is a rendered form of beef or mutton fat, processed from suet. It is solid at room temperature. Unlike suet, tallow can be stored for extended periods without the need for refrigeration to prevent decomposition, provided it is kept in an airtight container to prevent oxidation.In industry,...
oil.
Contemporary fabric softeners tend to be based on quaternary ammonium
Quaternary ammonium cation
Quaternary ammonium cations, also known as quats, are positively charged polyatomic ions of the structure NR4+, R being an alkyl group or an aryl group. Unlike the ammonium ion and the primary, secondary, or tertiary ammonium cations, the quaternary ammonium cations are permanently charged,...
salts with one or two long alkyl chains, a typical compound being dipalmitoylethyl hydroxyethylmonium methosulfate. Other cationic compounds can be derived from imidazolium, substituted amine salts, or quaternary alkoxy ammonium salts. One of the most common compounds of the early formulations was dihydrogenated tallow dimethyl ammonium chloride (DHTDMAC).
Anionic softeners and antistatic agent
Antistatic agent
An antistatic agent is a compound used for treatment of materials or their surfaces in order to reduce or eliminate buildup of static electricity generally caused by the triboelectric effect. Its role is to make the surface or the material itself slightly conductive, either by being conductive...
s can be, for example, salts of monoester
Ester
Esters are chemical compounds derived by reacting an oxoacid with a hydroxyl compound such as an alcohol or phenol. Esters are usually derived from an inorganic acid or organic acid in which at least one -OH group is replaced by an -O-alkyl group, and most commonly from carboxylic acids and...
s and diesters of phosphoric acid
Phosphoric acid
Phosphoric acid, also known as orthophosphoric acid or phosphoric acid, is a mineral acid having the chemical formula H3PO4. Orthophosphoric acid molecules can combine with themselves to form a variety of compounds which are also referred to as phosphoric acids, but in a more general way...
and the fatty alcohol
Fatty alcohol
Fatty alcohols are aliphatic alcohols consisting of a chain of 8 to 22 carbon atoms. Fatty alcohols usually have even number of carbon atoms and a single alcohol group attached to the terminal carbon. Some are unsaturated and some are branched...
s. These are often used together with the conventional cationic softeners. Cationic softeners are incompatible with anionic surfactant
Surfactant
Surfactants are compounds that lower the surface tension of a liquid, the interfacial tension between two liquids, or that between a liquid and a solid...
s used in the bulk of surfactants used in detergents, with which they form a solid precipitate. Therefore, they have to be added during the rinse cycle instead. Anionic softeners can be combined with anionic surfactants directly. Other anionic softeners can be based on smectite clays. Some compounds, such as ethoxylated
Ethoxylation
Ethoxylation is an industrial process in which ethylene oxide is added to alcohols and phenols to give surfactants. The invention of the process is attributed to Schöller and Wittwer at I.G. Farben industrie.-Production:...
phosphate esters, have softening, anti-static, and surfactant properties.
The softening compounds differ in affinity to different materials. Some are better for cellulose
Cellulose
Cellulose is an organic compound with the formula , a polysaccharide consisting of a linear chain of several hundred to over ten thousand β linked D-glucose units....
-based fibers, others have higher affinity to hydrophobic materials like nylon
Nylon
Nylon is a generic designation for a family of synthetic polymers known generically as polyamides, first produced on February 28, 1935, by Wallace Carothers at DuPont's research facility at the DuPont Experimental Station...
, polyethylene terephthalate
Polyethylene terephthalate
Polyethylene terephthalate , commonly abbreviated PET, PETE, or the obsolete PETP or PET-P, is a thermoplastic polymer resin of the polyester family and is used in synthetic fibers; beverage, food and other liquid containers; thermoforming applications; and engineering resins often in combination...
, polyacrylonitrile
Polyacrylonitrile
Polyacrylonitrile is a synthetic, semicrystalline organic polymer resin, with the linear formula n. Though it is thermoplastic, it does not melt under normal conditions. It degrades before melting. It melts above 300 degrees Celsius only if the heating rates are 50 degrees per minute or above...
, etc.
Silicone
Silicone
Silicones are inert, synthetic compounds with a variety of forms and uses. Typically heat-resistant and rubber-like, they are used in sealants, adhesives, lubricants, medical applications , cookware, and insulation....
-based compounds such as polydimethylsiloxane
Polydimethylsiloxane
Polydimethylsiloxane belongs to a group of polymeric organosilicon compounds that are commonly referred to as silicones. PDMS is the most widely used silicon-based organic polymer, and is particularly known for its unusual rheological properties. PDMS is optically clear, and, in general, is...
comprise the new softeners which work by lubricating the fibers. Derivatives with amine- or amide-containing functional groups are used as well. These groups help the softeners bind better to fabrics.
As the softeners themselves are often of hydrophobic nature, they are commonly occurring in the form of an emulsion
Emulsion
An emulsion is a mixture of two or more liquids that are normally immiscible . Emulsions are part of a more general class of two-phase systems of matter called colloids. Although the terms colloid and emulsion are sometimes used interchangeably, emulsion is used when both the dispersed and the...
. In the early formulations, soap
Soap
In chemistry, soap is a salt of a fatty acid.IUPAC. "" Compendium of Chemical Terminology, 2nd ed. . Compiled by A. D. McNaught and A. Wilkinson. Blackwell Scientific Publications, Oxford . XML on-line corrected version: created by M. Nic, J. Jirat, B. Kosata; updates compiled by A. Jenkins. ISBN...
s were used as emulsifiers. The emulsions are usually opaque, milky fluids. However there are also microemulsion
Microemulsion
Microemulsions are clear, thermodynamically stable, isotropic liquid mixtures of oil, water and surfactant, frequently in combination with a cosurfactant. The aqueous phase may contain salt and/or other ingredients, and the "oil" may actually be a complex mixture of different hydrocarbons and olefins...
s where the droplets of the hydrophobic phase are substantially smaller. The advantage of microemulsions is in the increased ability of the smaller particles to penetrate into the fibers. A mixture of cationic and non-ionic surfactants is often used as an emulsifier. Another approach is using a polymeric network, an emulsion polymer.
Other compounds are included to provide additional functions; acids or bases for maintaining the optimal pH
PH
In chemistry, pH is a measure of the acidity or basicity of an aqueous solution. Pure water is said to be neutral, with a pH close to 7.0 at . Solutions with a pH less than 7 are said to be acidic and solutions with a pH greater than 7 are basic or alkaline...
for adsorption to the fabric, electrolytes, carriers (usually water, sometimes water-alcohol mixture), and others, eg. silicone-based anti-foaming agents, emulsion stabilizers, fragrances, and colors. A relatively recent form on the market are the ultra-concentrates, where the amount of carriers and some other chemicals is substantially lower and much smaller volumes are used.
In recent years, the importance of delivering perfume onto the clothes has possibly exceeded that of softening. The perfume levels in fabric softeners has gradually increased, requiring high-shear mixing
High Shear Mixer
A high-shear mixer disperses, or transports, one phase or ingredient into a main continuous phase , with which it would normally be immiscible...
technology to be used to incorporate greater amounts of perfumes within the emulsions. Long term release of perfume on the fabric is a key technology now being utilized. Each country tends to have different perfume requirements and brands may have different softener/perfume ratio depending on the country.