CLOTHING FROM MILK FIBRE
Dr N.N.Mahapatra
B.Sc( Hons),B.Sc (Tech )(Bom)M.Sc ( Chem ),Ph.D ( Chem ),M.B.A( IMM,Cal)
C.Col FSDC ( UK),CText FTI ( Manchester ),Int Trg ( Australia)),Sen Mem ,AATCC (USA)
FIC ,FTA , FICS,FIE,FIIChE ,MISTE ( INDIA)
President
COLORANT LTD
(An ISO 9001:2008 & 14001:2004 Certified Company)
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3225,Phase IV ,
G.I.D..C.Vatva,
Ahmedabad-382445
Gujarat,India
Fibres like cotton Linen have ruled the world since the start of civilization . As we speak about innovation and technology China with its large scale production has invented new fibres like Milk and Soybean .Though in the 1940’ s the fibres were quite popular in America and Europe the market for it collapsed due to World War II . Now regenerated , these fibres are more efficient and durable than any other fibre invented before or existing today . Milk fibre was invented in 1930 ‘ s in Italy by Antonio Ferratti . It was manufactured from milk casein to compete with wool. Casein fibres have since being produced under various names in a number of countries ,
- Lanital in Belgium and France .
- Fibrolane in Britain .
- Merinova in Italy.
- Wipolan in Poland .
- Aralac in America
Casein is obtained by the acid treatment of skimmed milk . The casein coagulates as a curd which is washed and dried , and then ground to fine powder . 35 litres of skimmed milk produce about 1 kg of casein . Today ‘ s milk fibre is environmentally friendly , superior in strength and has far better qualities than man –made fibres . Casein ( milk ) protein dates back many centuries when it was used as a binder for paints – paint with casein applied to 14 th and 15 th century churches still appears bright and unfaded. Proteins are obtained from skim milk,evaporated milk and condensed milk . There are about three pounds of casein in every 100 pounds of milk.
Production of milk fibre ;
Casein is obtained by the acid treatment of skimmed milk . The casein coagulates as a curd which is washed and dried , and then ground to a fine powder . 35 litres of skimmed milk produce about 1 kg of casein .
Casein is dissolved in caustic soda solution . The solution is allowed to ripen until it reaches a suitable viscosity , and is then filtered and deaerated .The spinning solution is wet spun by extrusion through spinnerets into a coagulating bath containing sulphuric acid ( 2 parts ),formaldehyde( 5 parts ), glucose ( 20 parts )and water ( 100 parts).the jets of solution coagulate into filaments in a manner similar to the coagulation of viscose filaments. But the next process is very critical as the fibre has to be treated chemically to harden it . The process is commonly described as “ hardening “ , in that it minimized the softening effects of water .Treatment with formaldehyde forms the basis of many hardening techniques . In the plant scale bunches of filaments are collected together into a tow as they leave the coagulating bath , and are then steeped in formaldehyde solution . the filaments are subjected to drawing at this stage . After treatment , the tow is washed and dried , crimped mechanically , and then cut into staple fibre . Otherwise the tow to top convertor makes tops for blending with wool . Following are the varieties available in market .
staple fibre /tops
| fineness | length |
| 1.56 dtex | 38 mm |
| 1.56 dtex | 46 mm |
| 2.22 dtex | 76 mm |
Milk fibre has passed oeko-tex standard 100 green certification for the international ecological textiles . The milk fibre contains eighteen amino-acids , which is beneficial to human’s health and has the functions of nourishing and taking care of skin .The wet spinning technology , a unique spinning solvent is used , micro-zinc ions are is embedded in the fibre , after drying and after treatment , zinc oxide is produced , therefore it is bacteriostatic and durable . Casein fibre is produced almost entirely as staple , tow or top .
FLOW CHART OF MILK FIBRE PRODUCTION.
Casein —— mixing ( caustic soda and water )——- filtration ——-deaeration —– spinning —– tow ——–drawing —– hardening —– washing —– drying —– crimping —- cutter ——— baling .
Milk fibre resembles wool in having a soft warm handle .The fibres are naturally crimped , and yarns have a characteristic warmth and fullness of handle . It provides good thermal insulation . They are resilient , like wool. Casein fibres cannot be distinguished from wool fibres by chemical or burning tests , only by microscope . because chemical composition is so similar , casein burns like wool with odour of burning hair , has no surface scales like wool but is smooth and round when viewed under a microscope , is damaged readily by alkalis and mildews easily .
Properties of Milk fibre ,
| Properties | Casein | Silk | Wool | Cotton |
| Tenacity gm/den | 1.1-0.9 | 1-1.5 | 1.5-2.0 | 2-5.5 |
| Elongation, % | 60-70 | 25-45 | 25-40 | 6-10 |
| Density ,gm/cm3 | 1.30 | 1.34-1.38 | 1.33 | 1.50-1.54 |
| Moisture regain,% | 14 | 11.0 | 14-16 | 9 |
| Acid resistance | Good | excellent | excellent | Bad |
| Alkali resistance | Bad | good | bad | Excellent |
| Resistance to moth/fungus | Resistance to moth but not to fungus | Resistance to
Fungus but not To moth |
Resistance to fungus but not to moth | Resistance to moth but not to fungus |
| U.V resistance | bad | bad | bad | good |
The filaments are smooth –surfaced . cross section is bean shaped . the natural colour is white. When wet , the fibres lose much of their strength ; tenacity falls to 0.6 to 0.3 g/den .milk fibre tends to absorb moisture readily , and the fibres become swollen and soft . they may become plastic and sticky as the temperature is raised. The fibres become brittle and yellow on prolonged heating at over 100 deg c. It burns slowly in air.flammability is similar to wool. The fibre base body does not have regular channels , which makes the milk fibre have as fine moisture absorption as natural fibre and better moisture conduction than synthetic fibres – milk fibre is both comfortable and permeable .fibres are white , fluffy , springy and have a pleasant odour . Even though casein fibre lacks certain desirable qualities of wool it was a way to replace wool at a lower cost . when mixed with viscose and wool ,casein helped in the conservation effort during world war II as a wool substitute. Though caseins can be laundered with care the same as wool , they loose strength when wet and must be handled gently . they cannot be kept damp for any length of time due to quick mildewing .
Today’ s milk fibre is environmentally friendly , superior in strength and has far better qualities than man-made fibres .
Blending of milk fibre ; When blended with other fibres casein added a soft draping quality and resilllliency to fabrics . Fibre was blended with wool for creating felt and with spun rayon,wool,mohair and cotton for attractive woven and knitted fabrics in a variety of weaves , textures and prints . The popular blends were wool -94% and casein fibre -6 % . , and viscose-50% and casein fibre – 50 %. Casein /cotton blends are popular for hosiery and carpets. A small amount of fibre is used for 100 % casein goods , but most casein fibre is blended with wool , cotton , rayon , nylon and other staple fibres . Blends containing casein may be spun on all the usual systems
- Cotton system – viscose/casein blends
- Woolen system. – casein/ wool or viscose
- Worsted system. – casein /wool or viscose blends.
- Flax system. – casein/viscose blends.
| TYPE OF BLENDS | COUNT |
| 100% Milk yarn | 10-80 Ne |
| Milk fibre /cotton | 10-80 Ne |
| Milk fibre /cotton/modal | 10-80 Ne |
| Milk fibre /Tencel | 10-80 Ne |
| Milk fibre /bamboo fibre | 10-80 Ne |
| Milk fibre/cashmere/wool | 16-80 Ne |
| Milk fibre/silk | 16-80 Ne |
| Milk fibre/camel hair | 16-80 Ne |
| Milk fibre/silk/cashmere | 16-80 Ne |
| Milk fibre/silk/cashmere/tencel/cotton | 16-80 Ne |
Chemical processing of Milk Protein Fibre ( Casein) ;
Milk protein fibre has different physical and chemical construction from natural protein fibre , care is taken in the following steps ;
- Desizing – Enzyme products may be used , preferally at pH 4.0 to 6.0 . If water soluble sizes have been used , desizing is not necessary .
- Scouring – Synthetic detergents should be used , preferably under acid conditions , e.g pH 6.0 .
- Bleaching – Casein fibre is generally white , and bleaching is not usually necessary . If required , it should be carried out under weakly conditions ,e.g pH 4.0 -6.0 as Casein fibres retain maximum strength and minimum swelling under these conditions . Hypochlorite bleaches should not be used . Bleaching may be carried out with Hydrogen Peroxide – 2 gpl at a pH of 8.0 using Sodium Pyrophosphate . It must be followed by careful washing and acidification with acetic acid . Normal optical bleaching agents may be applied .
- Dyeing – Casein absorbs moisture readily and does not have a highly orientated structure . Dyes can penetrate into the fibre without difficulty .
Casein can be dyed with dyestuffs used for wool . Acid , Basic , Direct and Disperse dyes are used where good washing –fastness is note a prime essential . Metal complex dyes give high wash fastness . pH of the dyeliquor should be between pH 4 & 6 . Dyeing is usually carried out at 90-95 deg c.
- Printing – Fabrics containing casein may be printed by block , screen ,& roller. Acid , basic , direct , chrome, mordant , azoic , vat or pigment dyes may be used .
- Finishing – Crease –resist finishes may be applied to blends containing casein fibre , using temperatures not higher than 160 deg c. for approximately 2.5 mins.
Uses of Milk Protein fibre ; One of the earliest uses for casein fibre was in the making of felt for hats . Casein /wool blends are used for knitted berets . Casein/cotton or nylon blended fabrics are used for interlock outerwear , T shirts , cardigans , jumpers etc. casein blended with wool, cotton ,viscose , nylon is used in Raschel cloths , coatings, blanket fabrics . Blends of casein and wool are made into pressed felts for use as floor coverings and used in conventional and tufted carpets . Pile carpets are made using casein -50% and wool or viscose -50% .
Acknowledgement – The author is thankful to Mr S.K Khandelia ,President , Chenab Textile Mills, Kathua ( J & K ) for giving permission to publish this article .
