MATERIALS Ana Marija Grancaric, Anita Tarbuk With the support of the Lifelong Learning Programme of the European Union 1
Footwear materials History of footwear materials First material evidence of the existence of shoes dates back to the Paleolithic (pre-historic era). But it is generally assumed that the usage of shoes began much earlier. From hemp and leather to plastics: 2
Footwear materials Natural materials Wool Cotton Jute Wood Horn Ivory Leather Natural caoutchouc Synthetic materials Nylon Polypropylene Polystyrene Polyethylene Polyvinylchloride Bakelite Epoxy resins Organic glass Polyurethane Synthetic rubber Color and varnishes: Shellac Resin Linseed oil Biopolymers EVA ( ) Adhesives: wax (paraffin, beeswax, carnauba) 3
Footwear materials Footwear materials Today! Due to its properties, Leather is considered indispensable in the footwear industry. Skin leather is the type of leather most commonly used thanks to its low price and good visual appearance. It should be noted that the artificial leather industry is so technically advanced that it is often difficult to assess whether the shoe is made of real or artificial leather. 4
Footwear materials Another important material used in footwear industry are the Textiles. Both natural and man-made fibers can be found in almost every shoe, used either as reinforcement, pads or linings. Other commonly used materials are: Metal (used for additional reinforcement or as accessory) Rubber and Plastics (used mainly in soles and heels, and sometimes can be found in the shoe itself) Glue (used for joining the different parts) 5
Footwear materials Natural fibers Vegetable fiber Animal fiber Mineral fiber Seed Cotton Kapok Akon Stalk Flax Hemp Jute Ramie Kenaf From husks Coconut From leaves Sisal Manila Raffia Keratin Wool Hair Mohair Cashmere Angora wool Camel coat Llama hair Fiber from other animals Silk Wild silk: Tussah Anafi Asbestos 6
New application of vegetable fibres cotton, flax, jute, ramie Cotton fibers usage in the footwear industry: such us fabrics for lining or for the upper part of a pair of shoes. Flax fibers 7
New application of vegetable fibres cotton, flax, jute, hemp, ramie The sole is of jute or ramie, upper part is made of cotton, flax or ramie, as well as sews. Hemp This is an interesting design by made vegetable fibers - bamboo 8
Footwear materials Man-made fibers From natural polymers From inorganic material From synthetic polymers Cellulose Viscose Copper Modal Liocelna Acetic Triacetate Protein Regenerated Protein PROT Alginate ALG Natural rubber fibres Carbonic CF Glass GF Metal MF Ceramic Organic Polyester Polyamide Aramid Polyacrylonitrile Modacrylic Polypropylene Polyester Chloric Fluorine Vinyl Elastane 9
New application of synthetic fibres Fibers from inorganic material Carbon fiber (CF) - It has high stiffness, high tensile strength, low weight, high chemical resistance, high temperature tolerance and low thermal expansion, what make them very popular in aerospace, civil engineering, military, and sports. Even highly expencive, they are usually combined with other materials to form a composite. 10
Footwear materials In the Footwear industry, plastics are used for making shoe soles, heels, miser, belt ornaments, and as replacement of natural leather Most commonly used plastics are: Polyvinyl chloride (PVC) Polyvinyl acetate (PVAC) Polyethylene (PE) Polypropylene (PP) Polystyrene (PS) Polyamide (PA) Polycarbonate (PC) Ethylene-vinyl acetate (EVA) Polyurethane (PUR) Bio-plastics: Polylactic Acid (PLA) 11
Footwear materials PVC Polyvinyl chloride is obtained by polymerization of the vinyl chloride In shoemaking industry is used soft PVC (with 20-50% softener), mainly for producing soles, heels and all injected shoe 12
Footwear materials PVAC Polyvinyl acetate is obtained by polymerization of vinyl acetate Single PVAC is unsuitable for forming, so it is mostly used as a copolymer with PVC 13
Footwear materials PE Polyethylene is obtained by polymerization of the ethylene (ethene) under various conditions (pressure, temperature, catalyst) In shoemaking industry it is used for producing fillings, heels and insoles 14
Footwear materials PP Polypropylene is obtained by polymerization of the propylene In shoemaking industry it is used for producing all height of heels, shoe molds and filling Propylen Polypropylen 15
Footwear materials PS Polystyrene is obtained by polymerization of styrene In shoemaking industry it is used for producing shoe soles and low heels 16
Footwear materials PA Polyamide is usually obtained by condensation and polymerization of diamine and dicarboxylic acid In shoemaking industry it is used for producing shoe soles, sports shoes, high heels and thin heelpiece 17
Footwear materials PC Polycarbonate is saturated polyesters of carbonic acid of the general formula In shoemaking industry it is used for producing soles and heels (-ORCO-) n 18
Footwear materials Nitributadien Rubber (NBR) It is resistant to oil, fuel and other chemicals. It contains more nitrile within the polymer, so it has higher resistance to oils but lower flexibility as a material. NBR is used in the preparation of specialized shoes, like coating from oil and chemicals. The shoe above has a pre-molded Rubber Nitrile Sole. 19
Footwear materials Thermoplastic Rubber (TR) Thermoplastic rubber (TR or TPR), one of the most common materials for making footwear outsoles, has been in use in the footwear industry since the 1960s. Although it is not suited to every type of footwear, outsole material TR is widely used in a variety of different types from everyday fashion/casual shoes to slippers (as it is flexible) and sneakers (as it is slip resistant). In the latter, application it is often seen in the form of a thin outsole bonded to a lightweight EVA midsole for cushioning. 20
Footwear materials PUR Polyurethanes Has properties similar to rubber Excellent material for getting plastics and synthetic fibers Can be both, thermoplastic and thermoset Thermoplastic PUR Constructed of linear macromolecules that are related with physical connections. At high temperature physical connections are torn and polyurethane can be shaped by casting. Thermoset PUR Can be formed up to 8 times. The molecules are linked by chemical bonds. Grid-like structure occurs at a temperature higher than 100oC. Can not be reformatted. 21
Footwear materials Pressing The plastic is melted in the injection molding machine and then injected into the mold, where it cools and solidifies. Molded Part Molten Plastic Raw Plastic Injection Molding Machine 22
Footwear materials Processing of Plastics is simple and short and the product immediately gets its final shape and appearance. Advantages of using Plastic Resistant to: air, water, bacteria Little density, low electrical and thermal conductivity, watertight Strength and toughness Smooth and flat surfaces (doesn't require further processing) Easy to maintain Disadvantages of using Plastic Not resistant to hightemperature Low permeability to air and water vapor Not degradable pollutant 23
New polymers EVA Ethylenvinylacetat is obtained by polymerization of ethylene and vinyl acetate Can be used alone or in combination with other polymers. (Commonly) is produced as expanded material in plates sole cropping (soles for lightweight summer shoes, middle soles) 24
New polymers Energy BOOST Designed with an energy-returning boost midsole, these running shoes feature a techfit upper and the TORSION SYSTEM for support. Energy-returning boost midsole keeps every step charged with an endless supply of light, fast energy; TORSION SYSTEM for midfoot integrity techfit technology for lightweight and flexible upper support Flexible textile upper with welded synthetic overlays for support and stability External heel counter for maximal heel fit and running comfort; micoach compatible ADIWEAR outsole offers the ultimate in high-wear durability 25
New polymers Energy BOOST Boost is a combination of EVA foam and TPU (Thermoplastic Polyurethane). Thousands of unique energy storing capsules are blown together to provide an energy return and performance comfort to the runner. We're confident runners have never before felt this level of comfort. Boost is soft, bouncy and provides the ultimate in performance; it's lightweight, durable, comfortable and springy. 26
New polymers Energy BOOST How does the technology work? It's a proprietary, non-eva foam that is made up of individual energy storing capsules that are then blown together in a unique molding process. During the development process, each capsule forms a skin on the outside which, when blown together forms the technology called Boost. There are more than 2,000 individual capsules in a size 9 Energy Boost shoe. 27
New polymers Energy BOOST What's the difference between regular EVA foam and Energy Boost? Since 1981, compression molded EVA has become the standard running shoe midsole. Even it is great because of the nature of EVA expansion, it starts breaking down after the first few months. In other words, the shoe you buy today will have significantly different performance after 100, 200, 300 miles of use. In the heat, in the cold, and after countless miles, Boost cushioning performs more consistently and doesn t lose its cushioning properties like standard EVA. 28
New Polymers Bioplastics 29
New Polymers Why bioplastics? Safer & more friendly for our planet Polymers made from renewable, biobased resources and has a considerably lower carbon footprint than other plastics. Biodegradable, leaving behind no harmful substances. Positive business impact Consumers are becoming increasingly aware of their impact on our planet and are starting to appreciate and seek out more environmentally friendly alternatives. Bioplastics also alleviate our reliance on increasingly expensive oil-based sources. 30
New Polymers BioPlastics Can be made from natural or synthetic polymers Natural: cellulose, stark Synthetic: BIO-PE, PLA-polylactic acid, PGA-polyglycol, PHB-polyhydroxybutyrate, PHA-polyhydroxyalcanoate 31
New Polymers 32
New Polymers Thermoplastic stark glycerol Thermoplastic stark Amilose Amilopectine Stark (patatoe, corn) Usage: Packing Fiber mixture Composites 33
New Polymers Polylactid acid (PLA) Made from sugar cane, sugar beet or corn 34
New Polymers PLA bioplastic applications Molded plastic parts Fibre Foam Film Safety helmet High heat resistance Durable Weavable Boots Low temperature impact High strength Consumer electronics High heat resistance Excellent surfaceappearance Durable Sportswear High heat resistance Good breathability Soft and tactile feel Washable and durable Fresh fruit packaging Transparent and compostable 100% biobased and recyclable Automotive industry High heat resistance Durable Hydrolytic stability Foamed inner shell High impact 35
Recycling Recycling leather How to recycle tanned leather is still an open question (not as evident as plastics which is simply melt and transformed into new products). Few solutions are offered: Repair the existing damaged product Find a new usage for existing product Transform leather waste into panels for various uses and products, e.g. design 36
Recycling Repair the existing damaged products various preparations and methods can give leather an old glow Suggested video: Repair Gucci Leather Sole/Busy Bee Newmarket http://www.youtube.com/watch?v=g9he6tkgoco 37
Recycling Find a new usage for existing products creative minds can give a whole new meaning to the old leather item or to an useless leather waste 38
Recycling Design from leather waste panels Is composed of leather waste from different usages - furniture, footwear, accesories and other factories. This leather is then ground into shreds, combined with water and then mixed with binding products, such as natural rubber and acacia wood bark. The leather is then shaped into a panel, sheet or a roll to be mechanically processed according to the customer s requirements (specific size, color, and texture). Panel design can have different uses, such as reinforcements in shoemaking, floors in construction industry, among others. 39
Thank you for your attention Virtual Campus, Lda. (Portugal) ΠΟΛΥΤΕΧΝΕΙΟ ΚΡΗΤΗΣ Technical University of Crete (Greece) Centro de Formação Profissional da Indústria do Calçado (Portugal) Sveučilište u Zagrebu, Tekstilno-tehnološki fakul (Croatia) Instituto de Biomecánica de València (Spain) Universitatea Tehnica Gheorghe Asachi Iasi (Romania) This project has been funded with support from the European Commission. This publication reflects the views only of the author, and the Commission cannot be held responsible for any use which may be made of the information contained therein. 40