Shoe Solings

Microcellular polyurethanes for shoe soling are of both the polyester and polyether types. Polyester types were developed first and owing to their generally superior mechanical properties they tend to be used in the thinner sole, high quality section of the market. Such polyester systems are usually based on quasi-prepolymers (made from part of the polyester and the MDI) and a resin blend made up of the rest of the polyester, the chain extender (usually butane diol), catalysts, surfactants and water to produce carbon dioxide to blow the foams. The use of a quasi-prepolymer enables the two 

A problem with the polyester systems is the need to melt the resins from their storage drum and the need for heated lines and tanks on processing machines. Because of this problem some polyester systems have been produced based on liquid or low-melting-point polyesters which require much shorter melting times and remain liquid for longer periods. 

The polyethers generally have a functionality greater than 2 to introduce some chemical crosslinking into the systems to improve the set-up and stiffness at demould. For fast reaction with the isocyanate the polyethers are usually poly(ethylene oxide)-tipped to give a high proportion of primary hydroxyl groups on the poly(propylene oxide)-based backbone. 

The polyether-based systems tend to be inherently lower in mechanical properties than the polyester types and this is particularly noticeable during demoulding when the units can still be soft and deformable. The principal 

Lower-viscosity diisocyanates have been developed to ease processing problems. These isocyanates are made by the partial conversion of MDI to carbodiimides. MDI adds to the carbodiimides to form uretoneimines which are particularly effective at disrupting the crystallinity of the MDI and lead to very low viscosity products with a functionality greater than 2  

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Shoe soles Shoe traction Shomger method Shop-assembled boilers... 

Cellular mbber has been used extensively as shoe soles, where its combination of cushioning abiUty and wear resistance, coupled with desirable economics, has led to very wide acceptance. In this case the cushioning properties are of minor importance compared with the abrasion resistance and cost. Other significant cushioning appHcations for cellular mbbers and latex foam mbbers are as carpet underlay and as cushion padding ia athletic equipment. 

Water-borne adhesives are preferred because of restrictions on the use of solvents. Low viscosity prepolymers are emulsified in water, followed by chain extension with water-soluble glycols or diamines. As cross-linker PMDI can be used, which has a shelf life of 5 to 6 h in water. Water-borne polyurethane coatings are used for vacuum forming of PVC sheeting to ABS shells in automotive interior door panels, for the lamination of ABS/PVC film to treated polypropylene foam for use in automotive instmment panels, as metal primers for steering wheels, in flexible packaging lamination, as shoe sole adhesive, and as tie coats for polyurethane-coated fabrics. PMDI is also used as a binder for reconstituted wood products and as a foundry core binder. 

Butadiene and styrene may be polymerised in any proportion. The Tfs of the copolymers vary in an almost linear manner with the proportion of styrene present. Whereas SBR has a styrene content of about 23.5% and is rubbery, copolymers containing about 50% styrene are leatherlike whilst with 70% styrene the materials are more like rigid thermoplastics but with low softening points. Both of these copolymers are known in the rubber industry as high-styrene resins and are usually used blended with a hydrocarbon rubber such as NR or SBR. Such blends have found use in shoe soles, car wash brushes and other mouldings but in recent times have suffered increasing competition from conventional thermoplastics and to a less extent the thermoplastic rubbers. 

The thermoplastic elastomer polyamides have found use in conveyor and drive belts, ski and soccer shoe soles, computer keyboard pads, silent gears in audio and video recorders and cameras, and thin film for medical applications. 

Urethane rubbers have found steadily increasing use for oil seals, shoe soles and heels, fork-lift truck tyres, diaphragms, chute linings and a variety of mechanical applications. Fabric coatings resistant to dry cleaning are a recent development. In many of these applications high elasticity is not an important prerequisite so that the polyurethane rubbers must be compared not only with other rubbers but also with a variety of thermoplastics. 

Attempts have been made to popularise cyclised rubber as an additive for use in shoe soling compounds but they have not been able to compete with... 

Shoe adhesives. CR adhesives are used for the permanent attachment of shoe soles. For difficult-to-bond sole materials (plasticized PVC, EVA foaming soles, thermoplastic rubber, SBR) graft polymer solutions of Neoprene AD-G combined with a polyisocyanate provide a good adhesion. Another major area for CR contact adhesives is the manufacture of leather goods, particularly leather shoe sole bonding and belt lamination. 

Important markets for TPE s include shoe soles, pressure sensitive adhesives, insulation, and recyclable bumpers. 

Polyurethane, thermoplastic TPU has excellent properties except for heat resistance (usually only up to 250°F 121°C). It is used in alloys with ABS or PVC for property enhancement. Typical uses are in automobile fascias and exterior body parts, tubing, cord, shoe soles, ski boots and other oil and wear resistant products. 

Microcellular elastomers16 bridge the gap between solid elastomers and low-density foams. Although they may appear to be noncellular, these materials have a microscopic cell structure and so are by definition high-density foams, with densities between noncellular solids and standard foams. The most commercially important applications include shoe soles, carpet backing, chair armrests,... 

The full-prepolymer, quasi-prepolymer, and one-shot techniques may appear to be quite similar, but they each have important bearing on equipment requirements and physical properties. The full-prepolymer method, for example, is die process of choice for making high-performance cast elastomers with superb dynamic properties, such as industrial bumpers and bushings. Quasi-prepolymers are used in less demanding applications like shoe soles, adhesives, and spray elastomers. One-shots make up the rest, including most foams and elastomers. 

Shear modulus, polyamide, 138 Sheet molding compounds (SMCs), 30 Shoe sole products, 205 Shore hardness gauge, 243 Side-chain liquid crystalline polymers, 49 Side reactions, in transition metal coupling, 477... 

Composite Particles, Inc. reported the use of surface-modified rubber particles in formulations of thermoset systems, such as polyurethanes, polysulfides, and epoxies [95], The surface of the mbber was oxidized by a proprietary gas atmosphere, which leads to the formation of polar functional groups like —COOH and —OH, which in turn enhanced the dispersibility and bonding characteristics of mbber particles to other polar polymers. A composite containing 15% treated mbber particles per 85% polyurethane has physical properties similar to those of the pure polyurethane. Inclusion of surface-modified waste mbber in polyurethane matrix increases the coefficient of friction. This finds application in polyurethane tires and shoe soles. The treated mbber particles enhance the flexibility and impact resistance of polyester-based constmction materials [95]. Inclusion of treated waste mbber along with carboxyl terminated nitrile mbber (CTBN) in epoxy formulations increases the fracture toughness of the epoxy resins [96]. 

Methylenedianiline is used to make an intermediate in the manufacture of polyurethane rubber used for making automobile parts, shoe soles, rubber wheels, and insulation foam. 

The samples most commonly tested in compression are foams and rubbers, which experience compressive forces during use. Very often, the polymer foams that experience compression are not readily visible to us, even though they are all around. Polymer foams are widely used in carpet underlay, upholstery, shoe insoles, backpack straps, bicycle helmets, and athletic pads. Solid rubbers are much more visible, including automobile and bicycle tires, gaskets and seals, soft keys on calculators, and shoe soles. 

Another major use for semi-rigid polyurethane foams is as shoe soles. In this application, their light weight, abrasion resistance, and shock absorbing properties are important. In safety shoes, chemical and oil resistance are important. Polyether-based foams are used in applications where microbial attack is common, such as shoes intended primarily for use on soil or grass. 

An isomeric derivative of natural rubber produced by a variety of chemical treatments. The products are resinous and find application as reinforcing agents in natural rubber compounds (particularly in shoe soles) and as rubber-to-metal adhesives. 

Rubber, thermoplastic elastomers and PVC are employed in the manufacture of a wide range of footwear trainers, shoe soles and Wellington... 

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