Magazine: A Yarn about Yarns
By Jos McKenzie in Synthetics on 26th Oct 2009 6:00
The world of synthetic turf has come a long way since its introduction over forty years ago. The outcome is a range of products that replicate the feel and look of natural grass while providing specialist surfaces for a huge range of sports and landscape applications.
One essential aspect of the synthetic turf manufacturing process is understanding the characteristics and variations of the yarns available. The choice of yarn is essential to the end product use. The yarn is the material stitched to form the product and the number of stitches and tufts, the stitch rate (number of stitches per metre) and the gauge. The gauge is the distance between each needle and can be ¾”, 3/8” or 3/16” and it contributes to the performance and durability of the end product.
There are three different types of yarn used, polyethylene, polypropylene and nylon.
# Polyethylene is soft, non-abrasive, supple, and durable, with a smooth and waxy texture and retains moisture.
# Polypropylene is slightly rough and more abrasive; it is rigid, more brittle, dry and repels water.
# Nylon is very rough and highly abrasive. It is also flexible, extremely resilient and retains moisture.
There are also different yarn constructions which result in different surface characteristics.
# Fibrillated yarn is a wide perforated tape (yarn) creating a lattice structure which splits into individual blades after use (slightly old-fashioned technology).
# Monofilament yarns are individually created tapes which are twisted together to form the yarn strand (more modern technology eventually replacing fibrillated yarns).
Monofilament yarns are either straight or texturised. A straight yarn would be used for football or rugby and would provide a slower surface reducing ball roll. A texturised yarn is ideal for a fast surface allowing non-directional ball roll for sports such as bowls and hockey.
Some yarns are produced with profiles to enhance performance which means they are shaped during the extrusion process (always monofilaments) in order to offer various performance qualities. For exa
mple, a C shaped yarn encapsulates infill while an S shaped springs back upright after wear.
The pile characteristics are determined by, the Dtex (weight (g) ÷ length (m) of yarn) or density of the yarn, the pile weight, the gauge and the stitch rate.
The pile weight is generally the most important factor when comparing different products. More yarn in a product means
# It is a thicker, denser surface
# it lasts longer
# it offers better performance; although for some sports surfaces, a lower density combined with selected infill material emulates natural surfaces better.
The products are made by tufting the yarn through the backing cloth. The yarn is cut underneath the backing cloth by knives and is then coated with latex backing on the reverse. This backing adds locks in the tufts and adds weight and stability to the finished product.
Once the surface has been produced it becomes part of a synthetic grass system. Th
e combination of different yarns, the way in which they are tufted and backed and the base on which they are finally laid, along with appropriate infill material if required, all contribute to the quality, durability and performance of the final surface.
As a system for sports surfaces, you need to look at all the variables from the groundwork, surface construction, shock pad, yarn and infill selection, to get the optimum playing surface for the individual sports. They all need to work together to achieve the desired result.
Jos McKenzie, TigerTurf NZ Ltd
Background to the NZ Sports Field Forum
The NZ Sports Field Forum is dedicated to the sharing of information about all aspects of sports field maintenance and administration. The Forum began in Auckland in 1993, when Bruce Paton, a Sports Parks Officer with Auckland City Council called the first gathering of sports field officers from several of the councils in the Auckland Region. The Forum became an Incorporated Society in October 2002, and now has a membership of almost 200 people from throughout NZ, located from Kaitaia to Invercargill. Membership is drawn from contractors, schools, stadiums, consultants, sporting organisations and councils. Membership is free.
Members receive the Forum’s bi-monthly newsletters, news flashes, job vacancies, and invitations to Forum field days, seminars, as well as the New Zealand Turf Conference & Trade Show held every two years.
If you have any questions regarding the Forum, or are interested in becoming a member, please email the newsletter editor, Bobbie-Jo Harvey, on sportsfieldforumnz@gmail.com
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26 Oct 09 by Peter Bass
Looks like a giant sewing machine 
You Can't Handle The Truth. Bass atYa
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Monofilament yarns are either straight or texturised. A straight yarn would be used for football or rugby and would provide a slower surface reducing ball roll. A texturised yarn is ideal for a fast surface allowing non-directional ball roll for sports such as bowls and hockey.
mple, a C shaped yarn encapsulates infill while an S shaped springs back upright after wear.
The products are made by tufting the yarn through the backing cloth. The yarn is cut underneath the backing cloth by knives and is then coated with latex backing on the reverse. This backing adds locks in the tufts and adds weight and stability to the finished product.
e combination of different yarns, the way in which they are tufted and backed and the base on which they are finally laid, along with appropriate infill material if required, all contribute to the quality, durability and performance of the final surface.
The NZ Sports Field Forum is dedicated to the sharing of information about all aspects of sports field maintenance and administration. The Forum began in Auckland in 1993, when Bruce Paton, a Sports Parks Officer with Auckland City Council called the first gathering of sports field officers from several of the councils in the Auckland Region. The Forum became an Incorporated Society in October 2002, and now has a membership of almost 200 people from throughout NZ, located from Kaitaia to Invercargill. Membership is drawn from contractors, schools, stadiums, consultants, sporting organisations and councils. Membership is free.
