Measuring the Mechanical Properties of Leather and Textiles – Introduction

Leather and Textiles Testing using a Texture Analyser

The textiles and leather industries employ millions of people worldwide, turning raw materials such as natural fibres (cotton and wool) and synthetic fibres (polyester) or treated, tanned hide into finished products such as clothes and footwear, using multiple complex processes. 

Research and Development in the leather and textiles industries are now more important than ever before. Customers are driven to purchase eco-friendly alternatives to traditional materials, seeking out textiles that require a lower volume of water for growth (e.g. hemp as an alternative to cotton), recycled leather and textiles, textiles that consume a large amount of carbon dioxide during their growth (e.g. bamboo) and vegan alternatives to silk and leather.

Vegan leathers were until recently made from PVC. However, novelty value and customers’ desire for reducing plastic manufacture, have caused plant-based leathers to become increasingly popular. These can be made from a wide variety of plant materials, including pineapples, apples and crop waste. 

These alternative materials must still perform satisfactorily, in applications that cause them to be subjected to high and fluctuating stresses, and frequently harsh environmental conditions. 

WHY TEST TEXTILES AND LEATHER? 

Within the textiles industry, the use of mechanical testing with a Texture Analyser helps to ensure consistently high quality of products at every stage from raw materials, to dyed fabrics and through to the finished product. The same is applicable to the leather industry. There are many specific test methods for each industry, including International Standard methods. Although they are generally grouped separately, the basic methods used for each have a lot of overlap. Testing these materials allows product quality to be monitored, the product standard to be assessed, to aid the research and development process and to know the performance of the product at every stage of its manufacture.  

For example, sets of specific tests exist for fibre testing, yarn testing and fabric testing. Fibre testing might include rigidity, friction, strength and fineness measurements; yarn testing might include twist measurement and yarn strength, and tests for fabric (woven, knitted and nonwoven) might include tear strength, seam slippage and colour fastness. The tests that are performed using a Texture Analyser are mechanical in nature, measuring physical properties. Most commonly, these are destructive, including tear resistance, compressive strength, tensile strength and puncture resistance, well-suited to the high precision of this type of instrument. 

The majority of these tests are not expensive or time consuming, and they provide valuable data regarding the properties of components, materials and completed products for either product development / routine process testing or quality control. When used in a quality control capacity, these tests help prevent faulty products from reaching the market. Leather and textiles testing ensures the products live up to the high expectations on the market and that they are strong and flexible enough to do the job that they were designed for. 

STANDARD METHODS 

Today, textiles come from all over the world. They might be formed in one country, dyed in another, and made into finished goods in yet another. To ensure that the same practices are used in this complicated international process, many companies follow agreed-upon standards related to industrial processes and the goods produced by them. There are many tests specific for parts. E.g. to test shoelaces and rubber soles for shoes, or zips and other closures for clothing. The tests in this article relate to sheet fabric and leather as well as tests relating to adhesive bonds and stitched seams. 

Standard methods are widely used in industry. They are not compulsory, acting instead as guidelines for materials that have to meet certain requirements and safety laws. Standards specify the conditioning processes, test instruments used and test atmosphere and conditions required for repeatability between laboratories. 

In all leather and textile tests, consideration must be paid to the orientation of the sample with respect to the warp and weft (fabric grain direction), sample geometry and to the coated / underside of leather samples. Most standards for leather and textiles specify these test conditions as well as conditioning procedures, and these should be followed for good repeatability, as well as to comply fully with the standard. Alternative methods to standards are possible whereby a test can be created that focusses on a particular property that needs to be measured or a quality issue that needs to be identified. Empirical or imitative methods can be developed easily and bespoke probes and fixtures created to support a material in a particular way that necessitates its successful testing.

Read the next instalment Measuring the Mechanical Properties of Leather and Textiles – Tensile Tests on the blog next week. 

There is a Texture Analysis test for virtually any physical property. Contact Stable Micro Systems today to learn more about our full range of solutions.

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For more information on how to measure texture, please visit the Texture Analysis Properties section on our website.

The TA.XTplusC texture analyser is part of a family of texture analysis instruments and equipment from Stable Micro Systems. An extensive portfolio of specialist attachments is available to measure and analyse the textural properties of a huge range of food products. Our technical experts can also custom design instrument fixtures according to individual specifications.

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