1. Swimwear Fabrics Basic Characteristics & Development
Dr. Jimmy Lam
Institute of Textiles & Clothing

2. Swimwear Fabrics Agenda
Swimwear Fabric Historical Development
Swimwear Fabric Characteristics
Swimwear Material: Spandex
Fiber & Fabric Requirements
Caring of Swimwear Fabrics
New Development (1): UV protection
New Development (2): Competitive Swimming
New Development (3): DuPont Sorona

3. Historical Development of Swimsuit Fabrics (I)
In the 1920s, swimsuits were made in pure silk, for lightness, while racing and training costumes were made from cotton.
Navy blue was the only colour option.
Silk was more costly than cotton, but it had several advantages: lightness, strength, elasticity and feel.
Extensive use of silk and cotton continued through 1930s and 1940s.
In 1957, Australian swimmer Dawn Fraser developed a new competitive swimsuit for Speedo- fabric with nylon.
On the synthetics, nylon was the most favoured because of its strength, elasticity and the ease with which it took colour with dyed.

4. Historical Development Swimsuit Fabrics (II)
Nylon is light in weight, water repellent quality which meant it was quick drying.
With the introduction of nylon, colours other than navy began to appear. Red, royal blue were the most popular.
In 1972 Munich Olympic Games, Lycra was introduced. It has excellent stretch properties and good recovery and lightness.
The durability of this elastomeric fibre was not a par with nylon. However, the high cost of Lycra was restricted to competitive swimwear fabrics, rather than all-purpose wear, in which nylon remained dominant.

5. Today’s Swimwear Fabrics
There have been many developments in swimwear fabrics today. For example:
Sun Select fabric from Triump allows tanning through the swimsuit; it has been designed to block harmful UV rays to penetrate to the skin.
Speedo’s Scubasuit is made in a dense fabric which has a sun protection factor (SPF) of over 30, dry or wet to help the wearer practise “safe sun”.
Triump has developed a material which is quick drying, handy for swimming holidays. It is a mixture of nylon and Lycra with a layer of Telfon, meaning water rolls off the surface of the suit.

6. Basic Characteristics (I)
Opacity
i.e. not able to see through when wet (by adding acetate/nylon for liner)
Higher order of stretch and recovery
One of the most important properties of fabric that is intended for swimwear is recoverable stretch or elasticity
swimwear fit the figure tightly, and must be stable to elongation when wet
Higher order of resistance to abrasion

7. Basic Characteristics (II)
Higher fabric bursting strength
used for tight-fitting beach styles, fibers and yarns are important
Colour fastness to light
under explore under strong sunlight
Colour fastness to sea and pool water
Given the requirement for knitted fabric, what kind of stitch and structure are suitable for swimwear ?

8. Spandex Fiber (I) Introduction
In textiles, the man-made fibre with high degree of elasticity used for swimwear is known as Spandex.
Spandex is composed of at least 85% polyurethane by weight.
Such fibres are generally used for their highly elastic properties.
Trademarked fibres in this group are Lycra, Numa, Sapndelle and Vyrene.
Such fibres have, for many textile purposes, largerly replaced natural and synthetic rubber fibers.

9. Spandex Fiber (2) Characteristics
Although somewhat weak in the relaxed state, Spandex fibres can be stretched about percent beyond their length without breaking and quickly return to their original length.
The fibre, usually white and dull lustre, is readily dyed and absorbs very little moisture.
The fibre melts at 250 C and yellows upons prolonged explore to heat or light.
Items made of Spandex can be machine washed and dried at moderate temperatures.
Use of chlorine bleach can produce yellowing.
Spandex fibres are frequently covered with other fibres like nylon.

10. Spandex Fiber (3) End uses
Spandex is used in such apparel as foundation garments. Support hosiery and swimsuits.
It is light in weight and cool.
It is resistant to deterioration from body acids and it is easily laundered and quick-drying
Source: Briantanna Encyclopedia 2004

11. Fibres for swimwear
Nylon is used for most swimwear. Man-made, nylon is strong, abrasion-resistance and lightweight.
Polyester is also strong, resilient, wrinkle resistance and washes easily. Best when used in blends with cotton.
Cotton is a natural fibre which is strong, inexpensive and absorbent and comfortable in hot weather.
(But it is heavier in weight and wet easily)
Elastane is a synthetic stretch fibre which is present in most swimwear, being blended with nylon, polyester or cotton. It gives swimwear its stretch and resilience.

12. Fiber and Yarn
Generally, textured filament with modified into stretch yarn on false twist are more appropriate for use in swimwear than spun yarn (nature fiber)
For spun yarn, worsted system yarn is preferred over woolen system for swimwear, with high twist factor (finer and stronger yarn for knitting)

13. Swimwear Material Speedo: P.B.T. Endurance
One piece swimsuit from 45% polyester and 55% P.B.T. , a polyester variant, giving superior recovering properties

14. Fabrics for swimwear
Tricot is a technique of knit which produces adequate two-way stretch. Either smooth or structured, lustrous or matt, plain or printed
Jersey is used mainly in cotton and cotton polyester blends. Elastomeric is required for stretching and body fitting.
(Which structure is better for swimwear, single knit or double knit?)
Wovens are mainly used for coordinated breach wear items such as skirts and shirts.
Can we use woven fabric for swimwear?

15. Fabric Structure (I)
Amongst all knitted fabrics which are not made from stretch yarns and do not have rubber threads, the most elastic structure is 1x1 rib
Rib structure is better for swimwear (instead of plain) because
rib structure trends to be more opaque (without adding lining) and more dense;
rib structure is more elastic than single jersey (single jersey can add elastic yarn to overcome it)
Common Rib structure for swimwear
interlock
swiss pique
using stretch nylon and stretch polyester with /without spandex.

16. Swimwear Knit Structure: Warp Knit Structure
Speedo: S2000
One piece swimsuit from a warp knitted polyester elastane fabric with high filament polyester micro fiber yarns and finished with thermal treatment

17. Fabric Structure (II)
In whatever structure, the necessary elasticity is achieved by either laying-in or knitting-in elastomeric yarn, preferably spandex over rubber because of its lighter weight.
The fabric stretch is affected by:-
the fabric structure
whether the elastomeric yarn is used in bare or covered form

18. Fabric Structure (III)
A covered form yarn (spandex with an outer sheath of yarn) will normally restrict on its elasticity
The degree on its extension and return from elongation will depend on the amount of covering.

19. Caring for swimwear
Always warm hand wash with mild soap, rinse after wear in cool water, drip dry out of direct sunlight.
Do Not use strong detergents or bleach roll up when wet dry clean or iron tumble dry.
Avoid contact with rough surfaces, excessive contact with suntan lotions and oils harsh chemicals present in some pools or hot spas.

20. New Development Lessons from Australia
Apart from design, stretch and fit, new developments are needed for modern swimwear.
They are Ultra-Violent (UV) protection and reduce water friction for Olympia game (Competitive Swimming)

21. UV protection swimwear (1)
The effects of UV radiation are considered to be cumulative.
Apart from direct exposure to the sun, the reflection off the water or sand can give you increase dose of UV.
The risk of sunburn is much greater high on a mountain slope because UV increases by around 15% for every 1000 meters above sea level.
Hats sun glasses and scientifically designed fabrics for clothing provide the best protection against sun damage to skin.

22. Sun Protection (UV radiation)
Swimsuit for children.
The swimsuit covers all the body
With high percentage of Lycra

23. UV protection swimwear (2)
Research from the University of New South Wales under the Dept of Fibre Science and Textiles is conducted programme in sun protection, structures and rating for making UV protective swimwear.
Initial work found that:
Lycra fibres provide high UV rating (strong protection), however, they never exceed 20% of fibre content.
Cotton fibres when wet (under water) decreases in UV rating by as much as 50% (reduce protection)
Knitted fabrics will also stretch and UV rays can penetrate such open structure, especially on shoulders.
Colour of the fabric play a significant role too.

24. Ultraviolet Protection Factor (UPF)
Over-exposure to solar ultraviolet radiation (UVR) can cause sunburn, skin damage and increased risk of skin cancer.
Clothing provides one of the most convenient forms of protection against UVR but not all garments offer sufficient sun protection.
The UPF rating indicates how effective a fabric is at blocking out solar ultraviolet radiation. The testing is performed according to Australian /New Zealand standard AS/NZ4399.
UPF ratings range from 15 to 50 with higher ratings indicating more effective blocking and therefore better protection for the wearer of a garment made from the fabric

25. Factors affecting UPF Rating
Composition of the yarns (Polyester, cotton)
Tightness of the weave or knit (tighter improves the rating)
Colour (darker colours are generally better)
Stretch (more stretch lowers the rating)
Moisture (many fabrics have lower ratings when wet)
Condition (worn and faded garments may have reduced rating)
Finishing (some fabrics are treated with UV absorbing chemicals)

26. Competitive Swimwear
Besides UV protection, there was an emphasis on practical swimwear, especially in competitive swimming.
Olympic swimmers felt better in one piece swimsuits such as skin suit.
In 1972 Munich Olympic game, these suits were manufactured from very fine cotton that became virtually transparent when wet.
Today, this skin suit was made from a thin, light weight Lycra/nylon mixture, which would cling closely to the body and reduce drag.
Reducing drag for competitive swimming has been a goal for designers and manufacturers, and Swiss Olympic swimmers in 1972 decided to wear suits which were glue around the neck, leg and arm openings, which prevented water and air bubbles from entering the suits.

27. Competitive Swimwear for Olympia Game
Training suit with a high neck from 80% nylon, 20% Lycra. It is soft and sticky to touch, lightweight, fast drying. And offers resistance to chlorine.
Source: Maru Skooba

28. Competitive Swimsuit for Olympia Game
Speedo: Aquablade
One piece swimsuit from Polyester/Lycra. With high neckline, boy short legs and silicon ridges

29. Competitive Swimwear (2)
Arena and Speedo, two major swimsuits manufacturers, produced swimsuits for Montreal Olympia, worn by American, British, Russian teams.
The major advantage was that the body was completely compressed by suit.
The embarrassment caused by the suit’s transparency was reduced by the use of highly coloured patterns.

30. New Fiber Development from Du Pont: Sorona

31. New Development DuPont Sorona
Sorona® polymers have a unique combination of characteristics that help create softer fibers with superior comfort-stretch and recovery. Unlike nylon or polyester, the Sorona® dyeing process makes it possible to create a single fabric with many different colors in it at atmospheric temperatures.

32. Untextured Fiber Recovery versus Stretch as a function of polymer content
Both flat and textured yarns made from Sorona® fibers may be made into fabrics with advanced levels of comfort fit. As shown in the chart, fully drawn flat yarn made with Sorona® recovers 100% from approximately 120% strain. Even at higher levels, Sorona® fibers recover completely, returning to their initial form.

33. DuPont Sorona Softness
Both flat and textured yarns may be created from Sorona® polymer, bringing an exceptional new level of softness to any fabric at an easily workable denier. The stress-strain curves in the chart demonstrate that flat yarns made with Sorona® fibers are softer than either polyester or nylon, at the same denier, because less effort is required to bend Sorona® fibers. Nonwovens, such as medical garments, monofilaments and brushes, are softer and more resilient with Sorona

34. Smart Fibre
These unique properties — combined with fast drying, colorfastness, chlorine resistance, resilience, static protection, stain resistance, and easy care — make fibers made with Sorona® the obvious choice for a wide range of apparel applications, including casual wear, ready-to-wear, swimwear, activewear, outerwear and intimate apparel. Fabrics made with Sorona® soon will be available to apparel companies and top garment designers.

35. Sorona Swimwear
Alone or blended with other fibers, DuPont™ Sorona® offers all of the smart characteristics designers, manufacturers and consumers look for in swimwear:
Bright color vibrancy for deeper, richer colors
UV and chlorine resistance for brilliant color performance
Incredible print clarity and crisp color definition
Colorful good looks that last, swim after swim

36. DuPont Sorona: Performance Attributes

37. Comfortable, easy-care swimwear made with Sorona®.

38. Discussion What kind of fibers are used for swimwear?
What kind of knitting structures are suitable for swimwear?
What are the requirements for competitive swimwear?
What are the latest developments of fiber technology for swimwear?