By R.N Kanungo & Associates . Published in JTA:: July – August’ 2018.

An Exhaustive Information on Polypropylene Fibre Manufacturing process, it’s Industrial Uses, World Marketing trends and their future prospects are here.

Polypropylene in Apparel Fabrics and Its Future Prospects- An Overview
R. N. Kanungo*1 & (Dr.) S. R. Vengsarker2 1Snig Consultancy Services, Ahmedabad, 2Former CEO, Zenith Fibres Ltd. Vadodara.
Abstract Polypropylene (PP), the synthetic fibre of Olefin family of polymers, in recent years, has been seen to be consistently gaining grounds and making inroads into the world-wide textile scenario as the second most important fibre next to Polyester.At present, PP fibres share almost 6-7% of the global all fibre production and around 9-10% of the total synthetic fibre output. The manufacturing processes of PP fibres and yarn in the global market that are available mainly in three distinct categories as a) Split (Slit) films / Tapes, Monofilament yarns (Monofils) b)Multifilament yarns and Staple fibres and c) Spun bonded non wovens have been briefly described. In addition to the present traditional usages of PP filament yarns and staple fibres in sectors such as textile yarn, industrial yarn, yarns for carpet applications, spun-bonded non-wovens, knitted socks and stockings etc.,new market niches and demand for these fibres and yarns seem to be continuously on the rise in the world wide consumption and usage in the areas ofsportswear, active wear, home furnishings,medical and hygiene products, functional textiles, geo textiles, agro textiles and other technical textileproducts. Besides, usages of PP being primarily dominated in economies with High per capita GDP countries like Western Europe,North America, Japan and more recently in China, the main focus of future market growth of PP fibre seems to remain in the ‘Apparel sector’ because of its unique fibre properties and also due to the present global demand of PP fibre in the apparel segment. Future market prospects of PP fibres, in terms of innovative differentiated products which can add value substantially are a must and their application in main stream garment sectors through Primary, Functional,Comfort and Aesthetic variants of fibre properties for the development of newer products with desired fabric attributes and composite properties have been emphasized.
Keywords polypropylene (PP), polymer, staple fibre, filaments, apparel, comfort, aesthetics, differentiated, desirable characteristics,synthetic fibres, fabric attributes, and composite properties.

1. Introduction

Since the advent of the three major synthetic fibres ie. Nylon in 1938, followed by Polyester and Acrylics in the 1950’s, man-made synthetic fibres have been consistently developed and grown in volume as well as in global consumption (1). The overall fibre production world wide in the year 2016-17 has almost grown to more than 100 million tons including the production of New generation High tech and High performance synthetic fibres etc. The man-made synthetic fibres including the man-made natural cellulosics and proteins such as Viscose Rayons, Cupro, Acetates, Lyocell, Tencel etc. presently, have raised their share of production volume and market consumption to more than 70 percent of global all fibre production leaving around 30 percent to exclusively natural fibres such as Cotton, Silk, Wool, Jute ,Linen etc. as against a respective share ratio of 60:40 existed in 2002-03, a decade and half ago.(2,3)
Amongst the synthetic fibres, however,today Polyester occupies the leading position and dominates the global fibre scene by having almost three-fourths (70-75 %) of the total synthetic fibre output (excluding the man-made natural fibres), the remaining 25-30 % being the share of all other traditional synthetic fibres such as Polyamides, Acrylics, Polypropylene (PP), and other New generation fibres eg.Elastanes, PVA, PTEF, Carbon, Aramid and p-aramid fibres etc.

(Table-1)& (Fig.1)
Polypropylene in Apparel Fabrics and Its Future Prospects- An Overview
R. N. Kanungo*1 & (Dr.) S. R. Vengsarker2 1Snig Consultancy Services, Ahmedabad, 2Former CEO, Zenith Fibres Ltd. Vadodara.
Abstract Polypropylene (PP), the synthetic fibre of Olefin family of polymers, in recent years, has been seen to be consistently gaining grounds and making inroads into the world-wide textile scenario as the second most important fibre next to Polyester.At present, PP fibres share almost 6-7% of the global all fibre production and around 9-10% of the total synthetic fibre output. The manufacturing processes of PP fibres and yarn in the global market that are available mainly in three distinct categories as a) Split (Slit) films / Tapes, Monofilament yarns (Monofils) b)Multifilament yarns and Staple fibres and c) Spun bonded non wovens have been briefly described. In addition to the present traditional usages of PP filament yarns and staple fibres in sectors such as textile yarn, industrial yarn, yarns for carpet applications, spun-bonded non-wovens, knitted socks and stockings etc.,new market niches and demand for these fibres and yarns seem to be continuously on the rise in the world wide consumption and usage in the areas ofsportswear, active wear, home furnishings,medical and hygiene products, functional textiles, geo textiles, agro textiles and other technical textileproducts. Besides, usages of PP being primarily dominated in economies with High per capita GDP countries like Western Europe,North America, Japan and more recently in China, the main focus of future market growth of PP fibre seems to remain in the ‘Apparel sector’ because of its unique fibre properties and also due to the present global demand of PP fibre in the apparel segment. Future market prospects of PP fibres, in terms of innovative differentiated products which can add value substantially are a must and their application in main stream garment sectors through Primary, Functional,Comfort and Aesthetic variants of fibre properties for the development of newer products with desired fabric attributes and composite properties have been emphasized.
Keywords polypropylene (PP), polymer, staple fibre, filaments, apparel, comfort, aesthetics, differentiated, desirable characteristics,synthetic fibres, fabric attributes, and composite properties.
*All correspondences shall be addressed to, R. N. Kanungo, Snig Consultancy Services, Ahmedabad, Email : kanungorn@gmail.com
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Table 1.1 Global Synthetic Fibre Output in Million Tonnes Production in (Mil. Tons) % Share
1) Traditional Synthetic Fibres Polyester 54.00 75.50 Polypropylene 06.50 09.10 Polyamide (Nylons) 03.50 04.90 Polyacrylate (Acrylics) 03.00 04.20 ———————–Sub Total: 67.00 93.70 2) Spandex, Lycra and 02.50 03.50 other Elastanes 3) Other H. P. And High 02.00 02.80 Tech. Fibres ———————–Sub Total: 04.50 06.30 ———————–Grand total: 71.50 100.00
Figure 1.1 Global Synthetic Fibre Share in %
In recent years, however, the traditional synthetic Polypropylene (PP) fibre of Olefins family of Polymers is making inroads into the world-wide textile scenario as the second most important fibre next to Polyester, even gradually expanding its grip on the fields of Apparel, Home furnishing and other Technical textile sectors, usually, so far held on by natural fibre Cotton and synthetic Polyester fibres , in fact, pushing the Nylon fibres into the fourth place long ago. As for example, in one of the recent surveys carried out in 2015-16 (3) has revealed that, particularly on synthetic staple fibre market, PP fibre enjoys the third place with a share of 6% preceded by Polyester market share of 82% and Acrylic fibre share of 10% respectively. Polyamide (Nylons) and the other new synthetic fibres market share follow the PP fibres having shares of 1% each.
As per Mr.G.Mackie, the International Textile Consultant, Lisburn, Northern Ireland ( U.K.) was of the opinion that the ruling dynasty in the ‘fibre jungle’are still ‘King Cotton and Queen Polyester ‘ where the ambitious ‘ Prince Polypropylene'(PP) is steadily gaining ground in those applications which suits it best. (4).
2. What is PP : Manufacturing Technology PP (Polypropylene) fibre is a thermoplastic fibre and its structure is based on the monomer Cn H2n, thus the Molecular Formula is – ICH2-CH1I III ICH 3 In The PP polymer is manufactured from Propane gas in presence of a catalyst such as Titanium Chloride. Besides PP is also obtained as a by-product of Oil refining process.
As shown in the following Flow Chart of Polypropylene Process (Fig.2.1) the catalyst system is added to the diluents in the Polymeriser and a polymer is formed from Propylene gas .The polymer slurried in the diluent is first treated to decompose the catalyst, then filtered and purified. After drying, it is pelletised to produce the finished Pro-fax Polypropylene powder which is known as PP resin.(5)
Figure 2.1 : Flow Chart of PP Proceee
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2.1. Manufacture of PP Films/Filaments/Staple Fibres on Various Process Systems
The manufacturing of PP fibre and yarn are mainly divided into three distinct manufacturing sectors such as production of a) Split (Slit) Films/Tapes, Monofilament Yarns (Monofils) and Fibrillated Films b) Multifilament Yarns and Staple Fibres c) Spun bonded NonWovens.
2.1.1. Split (Slit) Films / Tapes, Monofilaments and Fibrillated Film Yarns As shown in the Flow Sheet diagram of Fibre Spinning Operations (Fig.2.2 and Fig.2.3), the PP resin is melted and extruded through a Spinneret in filament form.The filaments are then treated and drawn to get the proper crystallinity and molecular orientation in order to obtain
such desired characteristics in fibres as strength, abrasion resistance, resilience, elasticity and shrinkage etc. The fibres may also be heat set to alter its shrinkage, elasticity and flex resistance characteristics.The PP filaments may also be extruded in ‘Sheet form’ and are then ‘Slit’ into predetermined, very narrow ribbons by scribbing, cutting, perforating or other suitable techniques to obtain ‘Flat Filaments or Tapes.’These Split yarns are essentially ‘Monofilaments’ with a rectangular cross section, normally extruded at low speed with few spinneret holes and having filament diameter of .006″ or larger.The sheet form of manufacturing process is of small scale, easier,simple and considerably cheaper in costthan extrusion through a spinneret.(5). ‘Fibrillated Film Yarns’, however, are interconnected fibrous structures produced through the fibrillation of thin tapes. (Figure 2.3)
Figure 2.2 : Flow Sheet Diagram of Fiber-Spinning Operations
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MANUFACTURE OF PP FILMS/FIBRES/FILAMENTS ON VARIOUS PROCESS SYSTEMS
1. SPLIT (SLIT) FILMS/TAPES AND MONOFILS (a) SPLIT (SLIT) FILMS/TAPES -Essentially monofilaments with a rectangular cross section.
(Manufacturing Process- Small scale, Easier, Simpler & Cheaper)
Figure 2.3 : SPLIT (SLIT) FILMS/TAPES
(b) MONOFILAMENTS – Extruded at low speed and few spinnerette holes Fil.Dia. .006″ or larger (c)FIBRILLATED FILM YARNS-are interconnected fibrous structures produced through the fibrillation of thin tapes. Usage:- Artificial turf, Cordage, Secondary Carpet Backings etc.
2. MULTIFILAMENTS and STAPLE FIBRES SHORT SPIN ROUTE (less capital cost, less complicated than the of Polyester and Nylon) (a) UNTEXTURED FLAT FILAMENT YARNS. Generally cut into STAPLE FIBRES from Tows (large bundle of multifilament crimped yarn-generally 50,000 – 1 million deniers) (b) TEXTURED OR BCF (Bulked Continuous Filament) Yarns Manufactured on COMBINED SPIN DRAW TEXTURING LINES -Use in carpet pile fabrics.
3. SPUNBONDED NON-WOVENS An array of continuous filaments randomly arranged into a flat sheet of uniform thickness, produced directly from the melt on highly productive and specialized lines, in one continuous operation. Use in Secondary carpet backings, wide range of Geo textile applications, Furniture construction etc.
2.1.2. Multifilament Yarns and Staple Fibres The PP filament meltafter being extruded, treated and drawn through a ‘Short Spin Route’ are subsequently may be heat set and finally wound on to suitable desired package of ‘Untextured Flat Multifilament Yarns’. This process, normally involves less capital Cost and is less complicated than that of Polyester and Nylon. Further,depending upon the end use requirements of the fibre, yarn or fabric products the drawn filament ‘tows’ are subjected to processes of Crimping, Heat setting and Staple cutting from ‘tows’ of largely bundled ‘Multifilament Crimped Yarns’- generally of 50,000 to 1 million deniers, to arrive at the desired ‘Staple Fibres’. Alternately, the PP drawn filaments are also crimped and textured through the process sequences of Draw twisting and Heat setting or combined Spin-draw texturing lines to get the ‘Textured’ or’Bulked Continuous Filament (BCF) Yarns’ respectively. (Fig. 2.2 & 2.3)
2.1.3. Spun Bonded Non Wovens These are an array of continuousfilaments randomly arranged into a flat sheet of uniform thickness, produced directly from the melt on ‘Highly productive and Specialized lines’ in one continuous operation.(Fig.2.4)
3.0. Global Pp Fibre / Filament Production and Its Prospects At present, the total world production of all PP fibresincluding the Split film and Monofil category, on an average is hovering around 6 to 6.5 million Metric Tons (MT) since last decade and half, between the years (2000 – 2015).(6) as shownbelow and is expected to be slightly over 7 million tons during (201718) period which is approximately 10% of the total globalsynthetic fibre output.(7) and (Table 2 & Fig.5)
Table 2 : World Pp Fibre Production In Mil.Tons Year Production
2000 5.8 2005 6.4 2010 6.0 2015 6.2 AVERAGE PRODUCTION— 6.1 MIL.TONS
As could be seen above in Table-2 global PP fibre production has fallen around 1% per annum between the years (2005-10), mainly due to volatile Propylene (raw material) cost.
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Figure 2.4 : Global Pp Fiber Production in Million Tons (2000-2015)
3.0.1. Overall Share Of Production In Major Pp Fibre/ Filament Sectors
The overall share of production in each of the three major PP manufacturing sectors are shown in the following.(Table-3)
Table-3.1 : overall share of production
Pp Fibres And Filament avg. Yly.Production Percent Share (2000-15)
Sectorsin Million Tons % a) Split Films and Monofils. 2.0 32.8 b) Multifilaments and Staple Fibres. 3.0 49.2 (1.7 MF + 1.3 SF ) c) Filaments/Fibres for Spun Bonded Non-wovens. 1.1 18.0 Total –6.1 100.0
3.1 Future Growth Prospects Of Pp Fibres
The future growth prospects of PP fibres depend upon several inter related factors such as : a) Growth of Synthetic Fibres in general compared with Natural Fibres. b) The relative availability of Raw Material for PP vis-a -vis Nylon and Polyester. c) The cheap PP Polymer – little more than 5% Cost advantage over Polyester. d) Innovations in the use of PP fibresin Textiles, Home Furnishing and other Technical textiles and industry uses.
Within the last fifteen years from (2000-2015), the
growth of Synthetic fibres have been quite phenomenal as compared to that of all Natural fibres (includes Man made naturals of Cellulosic and Protein origin etc.) and,presently, the percentage share of Synthetics toall Naturals have increased to almost 67:33, from a ratio of 55:45 in 2002.(2)
In recent years, too, PP Staple fibres / filaments including Split Film yarns (tapes) and Spun bonded nonwovens for textile applications have made considerable progress and went through a period of explosive growth in 70’s and 80’s. However, at present it shares around 6% of the global market (approx. around 6-6.5 mil.tons out of more than 100 mil.tons of all fibre production and almost 9-10 % of the total global synthetic fibre output of 70-72mil.tons. (Fig.1.1)
As could be observed from Table-2 and (Fig.2.4),barring a marginal overall global PP fibre production fall of around 1% per annum between the years 2005-10, due to volatile raw material Propylene cost, it had facilitated Polyester substitution in some markets during that period. However, following 2010, due to more stable PP costs as a result of increased Propane dehydrogeneration and growing non woven markets, subsequent growth of PP markets are seen and are expected to rise further in future years.(6)
3.1.1. Focus Of Pp Market Growth And Future Trend PP is used primarily in economies with High per capita GDP- Western Europe, North America and Japan are key consumers and a significant part of the association derives from the Non -wovens and Carpet linkage of PP fibres – sectors most closely associated with ‘High income economies.'(7&8).
The following Table-4,illustrates the world PP fibre market (including tapes / split films) in various countries for the year 2000 and 2015.(8)
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Table 3.2 : World Pp Fiber Market
Countries world Pp Fibre Market Production In Million Tons
2000 2015 Western Europe 1.6 2.1 Eastern Europe 0.2 0.1 —— —–Sub Total 1.8 2.2 North America 1.1 0.8 South America 0.1 0.2 —— —–Sub Total 1.2 1.0 —– —–China 0.8 1.1 Middle East & Africa 0.8 0.8 North East Asia 0.6 0.6 South & South East Asia 0.5 0.4 —– —-Grand Total 5.7 6.1
A notable feature of PP, however is that its range of market penetration has been greatly assisted by its relatively low cost, since 2002 inspired by overcapacity in the Polyester marketand worldwide investments by conversion of Polyester lines to PP manufacturing has also risen to an all time high. Even in existing PP end uses new challenges are emerging and examining the cost base of the major synthetic fibres, particularly in Asia Pacific,in reality, PP the cheap polymer has enjoyed a little more than 5% cost advantage over Polyester. Besides, in recent years, China has also emerged as one of the PP fibre markets and expanded its market base significantly.(8)
Further, despite growing cost advantages, Polyester is technically limited in some marketsparticularly in Nonwoven sector, allowing more modest growth in PP and man-made Cellulosic fibres, thereby reducing, too,the share of Acrylics and Cotton to certain extent. Moreover,according to a survey on globalfibre mill consumption in major market segmenthas shown that the main focus of fibre growth will remain ‘Apparel sector’ which, of course is not the traditional market for Polypropylene (PP), and it also indicated that the Polymer to Yarn differentials in case of PP fibre fails to add value to its Polymer cost base as effectively as do the Polyester and Nylonsectors.(9) Hence, in case of PP, particularly, ‘Newor improved ‘ innovative differentiated products which can add value substantially
are a must for the future market growth.(9,10) 4. Pp:Usages And Application Areas
The world PP filament /fibre yarn and textiles market comprises basically of following major usages and applications.
a) Industrial yarn applications from Split/Fibrillated Films and Monofilaments/Tapes.b)PP Multifilament’s for Textile Yarn usagespredominantly in Carpet applications and in other Woven and Knitted sectors. c)Application of PP Filaments and Staple Fibres in Spun bonded Non-wovens and in majority of Technical textile products.(10).
4.1. Split Film Yarns ( Tapes ) And Monofils For Industrial Yarn Usages PP industrial yarn applications recently show increased usage of High Tenacity yarns in Ropes, Twines, Woven sacks, Bags, Belts, Strappings and Cordages etc. Fibrillated films and Monofilaments yarns are also used as Artificial turf, Secondary carpet backings, Outdoor furniture webbings, Automobile seat covers etc. (Figs.4 & 6)
PP Fibre Split Film Yarns Multi Filament Yarns Spun BondedI (Tapes ) and and Fabrics MonofilamentsII Staple Fibres :- Usage :
Fig.4.1 PP Fiber 1 4.2. Textile Yarn Applications And Usages Of Multifilament Yarns. PP Multifilament yarns predominantly used in Carpet
BCF for Carpet pile floor coverings. MF and Staple fibres : Filter Fabrics, Upholstery, Sports wear, Blankets, Functional Textiles, Medical Hygiene products, Ropes, Cordage, Apparels, Heavy Duty Tarpaulins Synthetic Grass, Awnings etc.
Woven Sacks, Bags, Strappings, Belts, Carpet Backings, Ropes, Cords, Twines etc.
Geo and Agro Textiles Baby Diapers, Medical and Hygiene products, Electric insulation, Batteryseparation Fabrics, CoatedFabrics etc.
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applications, at present show new market niches for textile applications. These demands are in Upholstery, Sportswear, Home and Functional textiles, Leisurewear fabrics such as active wear,swimwear, intimate apparels, jeans and hosiery etc. Increasing worldwide consumption of PP filament yarns are also seen in knitting and socks. (5)
Textured or BCF (Bulked Continuous Filament) yarns processed through combined Spin Draw Texturing lines are mostly being used as Pile yarn in Carpet pile fabrics’, Floorcoverings, Sweaters and Athletic apparels etc.(5) (Fig.4.1)
4.3.Usages And Applications Of Staple Fibres And Spun Bond Non-Wovens The majority of PP Staple Fibres are being used in Non-wovens, particularly in Spun bonded and Melt blown fabrics,Geo textiles,Agro textiles,Medical and
Hygiene products such as Absorbent products (Baby Diapers), Adult incontinence products, in synthetic fibre industry as PP bale wraps,Electric insulation, Battery separation and Coated fabrics etc.(11) (Fig.5.1).
Moreover, as Needle punched non-woven’s, PP textiles are used as Filter fabrics such as Cigarette and Technical filters, in Parcel shelves, Boot and Bonnet liners, Door panels, in Furniture fabrics as backing material, in Construction industry fabrics like asphalt and concrete etc.(12,13).
In Woven sectors, PP Staple fibres are consumed in Carpets as floor coverings, Filter fabrics, Antimicrobial fabrics, Health care and Hygiene products, Sports and leisure wear such as light weight Outer wear for climbers, Walking socks, Cycle shorts, Swimwear and Garments for divers, Thermal wear,Fire resistant fabrics
Figure.5.1 : Desirable Characteristics In Apparel Fabrics
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and other House hold textiles, Technical textiles applications such as in Motor vehicles, Agro and Horticultural products, Geo-textiles etc. (11,12&13).
5. Pp Fibresfor Apparel Development At present, globally PP has some modest representation, mainly in Socks, Thermal wear, Sports and Leisure wear apparels etc, but very little presence in the mainstream garment sectors. The restrictions appear to relate to certain ‘Physical and Chemical properties’ of the fibre which had been the limiting factors for its use in apparel development and therefore, the suitability of such fibre properties has to be properly weighed against the generally ‘Desirable Characteristics’ in the apparel fabric meant for certain end use in terms of four major aspects such as 1) Performance 2) Comfort 3) Aesthetics and 4) Economics which are summarized in Figure.5.1. 5.1.Pp Fibre Properties :(Technical Fibre Data The Technical fibre data of a typical PP fibre properties (13) are shown in the following table (Table-5)
Table 5.1 Technical Fiber Data
Fibre Properties
a) Tensile Strength – 3.5-5.5 gf/den b) Elongation % – 40 – 100 c) Abrasion Resistance – Good d) Moisture Absorption – 0 – 0.05 % e) Softening Point – 140 deg. C f) Melting Point – 165 deg. C g) Chemical Resistance-Generally Excellent h) Relative Density – 0.91 i) Thermal Conductivity – 6.0 (with Air as 1.0) J) Electric Insulation-Excellent k) Resistance to Mildewand Moth – Excellent
The suitability of the above PP fibre properties in Apparel developments and their advantages and drawbacks in terms of Performance,Durability, Comfort and Economic aspects of fabrics have been examined in detail as to how does Polypropylene (PP) fit into the apparel sectors have been shown in Figure.5.2
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FIBRE PROPERTY ADVANTAGES :
PERFORMANCE AND DURABILITY ASPECTS Sr No. Fibre Properties Remarks 1 Tensile Behaviour Tensile Strength and Breaking Elongation comparable with Polyester and Nylon 2 Elastic Recovery and Creep PP fibres exhibit a high degree of immediate elastic (cyclic Stress ) recovery- equivalent to that of Nylon and better than Polyester. 3 Toughness (Abrasion Resistance) Ranks well with the toughest fibres of Cotton and (ability of fibres to absorb energy) Polyester. 4 Resilience (Recovery from Resilience characteristics intermediate between Polyester Compressional loading) and Nylon. 5 Knot and Loop Strength For Textile deniers 2 to 7 dpf PP yarns show 80-85% Loop Strength and 95% Knot Strength. 6 Frictional Properties PP has relatively high co-eff.of friction against smooth surfaces 7 Colour Fastness PP has excellent colour fastness properties. 8 Hydrophobicity 0.04% (insignificantly small moisture absorption). 9 Chemical Inertness Exceptionally resistant to acids and alkalies. 10 Resistants to Insects and Microorganisms PP fibre does not support the growth of mildew or fungi nor an it be digested by insects or related pests. 11 Soiling and Staining Low propensity of PP fibres to soiling and staining and Easy cleanability. 12 Shrinking and Burning Strong shrinking behavior prior to melting. 13 Boiling Water Shrinkage Low Boiling water shrinkage of 2-5% of PP fibres. COMFORT ASPECTS 1 Low Specific Weight Lightest of all commercial fibres (Sp.gr. of PP-0.91) (for Comfort point of view and ease of Handling, a light weight fibre is desirable). 2 UV Stability Good UV stability of PP fibres. 3 Static Loading PP is less prone to Static loading than Nylon and Polyester. 4 Thermal Insulating Ability Thermal Conductivity of PP fibre is lower than any other fibre Except Wool. ( Values relative to Air 1.0 , PP-6.0, Wool-6.4 ) 5 Fast Drying property Much faster drying rates to draw Heat generated moisture from the body. (nearer to Coolmax ). 6 Pill Resistant property Unlike Polyester, PP fabrics have excellent Pill resistant Property. AESTHETIC AND ECONOMIC ASPECTS 1 General Appearance Clean appearance of PP fabrics. 2 Bending Recovery Recovery from Bending of PP fabrics generally poorer than Nylon. 3 Fibre Stiffness Fibre Stiffness (High Initial Modulus of PP fibres – Resis tance to strain) high offering good Dimensional Stability to fabrics. 4 Recyclability PP has the advantage of recyclability against Acrylic fibre.
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5.1.1. Fibre Property Advantages : Performance, Durability And Comfort Aspects Besides the PP fibres having the inherent drawback of low melting point, it has all the advantages and uniqueness in properties such as its Low specific weight, Chemical inertness, Hydrophobicity,Insulation ability, Low static loading, UV stability,Colour fastness, Excellent Pill resistant, Recyclability and finally Price to have its competitive advantage over other synthetic fibres such as Polyester,Nylons and Acrylics to fit into the Apparel sectors.
For example, PP fibres are used in some type of apparels and garments worn ‘Next to Skin’because the fibres absorb less water, consequentlyperspiration can pass from the skin through the PP garment to an absorbent outer layers, particularly useful in Sportswear, Active wear apparels and certain special Hygienic applications such as ‘Babies ever dry nappies.’
Further, in the context of application of PP in denim apparels,an experimental study (10) involving three Cotton indigo warp and PP weft fabrics and a fourth fabric of 100% all Cotton denim fabric of similar weight and fabric cover has indicated that the tested major fabric attributes for Performance, Durability, Comfort and Aesthetics have been found to be quite encouraging and superior in the three former Cotton warp/PP weft mechanical blended fabrics as compared to that of the fourth controlled 100% all Cotton fabric.
Moreover, in order to improve the functional requirements in a 100% Cotton apparel, yarns with major synthetic fibres such as Polyester, Nylon, Acrylics and more recently Polypropylene fibres either intimately or mechanically blended with Cotton are being increasingly introduced into the basic fabric structure and system. As a result, mechanical blended fabrics of 100% Cotton warp with PP weft or intimately blended Cotton/ PP weft are expected to significantly improve the ‘Abrasion resistance ‘ of the fabrics due to the PP component and hence the ‘Durability’ of such apparels as compared to that of a traditional 100% Cotton fabric. Additionally,the presence of PP fibres in the blend result in aesthetically enhanced softer, cleaner and somewhat lustrous fabrics especially designed for Women’s wear and other intimate wear apparels.
Thus , today ,100% PP fibres blended with Natural fibres like Cotton,Linen and other Man-made natural fibres such as Lyocell, Tencel, Modal, Viscose, Cupro, Bamboo,Soybean etc. which are rather being conve
nient to use in the weft direction with high strength 100% Cotton warp are also in vogue in the apparel fabric weaving sector.(12,13)
5.1.2. Fibre Property DrawbacksS With majority of the Physical and Chemical properties of PP having all the advantages, very few inherent properties of the fibre which have certain drawbacks for the Apparel development are listed below.(13)
a) Low Melting point of PP fibres, prevents it being ironed like Cotton,Wooland Nylon etc. b) PP fibre fabrics are difficult to dye except after substantial treatment and modification. c) Relatively poor UV and Thermal stability of PP fibre which requires addition of expensive UV stabilizers and Antioxidants during processing. d) Creeping due to PP ‘s low Tg (-15 to -20 deg.C) e) Poor adhesion to Glue and Latex f) PP is flammable which melts and burns like Wax.
6. Polypropylenein Newer Apparel Fabric Product Development Through Textile Differentiation In order that PP would have a wider role in Apparel sectors, the fabric attributes that can bring ‘Textile differentiation’ in New product development of fabrics have to be closely examined in terms of the 1) Primary variants of fibres such as a) Denier, b) dpf (denier per filament) c) Luster and d) Cross Section etc. and secondly 2) Functional Polymer based variants due to polymer additives such as a) Antibacterial b) UV Resistance c) Moisture absorbency d) Deep dye and Differential dye e)Differential luster f) Scents and Vitamins etc. In fact, today’s product development focus is dependent on these variants to develop products with composite properties and are not regarded as ‘Standalone differentiators.’
A typical examplefor a yarn for the PP Sports wear Apparel could be as follows. a) Low fibre denier for Light weight with Low specific weight PP properties b) Extra dull fibrefor Natural Aesthetics. c) Fine dpf for Comfort and Softness d) Octolobal Cross section for Cotton like appearance d) Polymer additives for 1) Anti bacterial, UV resistant,Anti Static and Anti electromagnetic properties for Speciality sports wear apparel.
Moreover, PP fibres in recent years, are also being used and developed as a lighter weight ‘Double
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