types of soles

Types of soling and its characteristics. use full for shoe industry in Pakistan.

1. Types of sole and its Characteristics Presenter : Mr. Waqar Ahmad Bajwa Prepared By: Mr. Khalil ahmad

2. 1.Leather Form: Sheet material for Cut soles, built units and insert for moulded plastic Normal Density Range: 0.95-1.05 Wear Resistance: Fair-moderate, not used at the rear heel Hardness: Hard Crack Resistance: Excellent Slip resistance: Adequate for walking . Improves with wear and when damp. Can be low when saturated. Other Properties: Not waterproof but can be impregnated to alter properties, has reputation for being able to “breath”, i.e water vapour permeable Other Comments: Has good aesthetic appeal. The cutting, trimming and finishing necessary add further add to the high cost Typical usage: Formal dress shoes, particularly for men

3. 2.Leather Fiber Board Form: Sheet material for Cut soles, built units and insert for moulded plastic Normal Density Range: 1.05-1.15 Wear Resistance: Fair-moderate, not used at the rear heel Hardness: Hard Crack Resistance: Excellent Slip resistance: Satisfactory for working Other Properties: Relatively stiff material adhesion dependent on laminar strength Other Comments: Performance is between those of leather and resin rubber Typical usage: Women’s courts and fashion boots with thin soles

4. 3.Resin Rubber Form: Sheet material for Cut soles, built units and insert for moulded plastic Normal Density Range: 1.25-1.50 Wear Resistance: Moderate, not used at the rear heel Hardness: Hard Crack Resistance: Good Slip resistance: Satisfactory for walking. Improves as initial paint finish wear off Other Properties: Can be finished in a range of attractive effects and be cold pressed to match the shoe bottom contour Other Comments: Has good aesthetic requires cutting, trimming and finishing, but possesses well and easily Typical usage: Women’s courts and fashion boots with thin soles, Men’s formal shoes,

5. 4.Crepe rubber Form: Sheet material for built sole unit Normal Density Range: 0.9 Wear Resistance: very Good Hardness: very Soft but temperature sensitive Crack Resistance: Very Good Slip resistance: Good dry Other Properties: Sensitive to oils, heat and direct sunlight. May shrink slightly Other Comments: A natural and uncompounded material from the rubber tree. Very limited in form and colour . Typical usage: Comfortable casual shoes

6. 5.Vulcanised Rubber (Compact) Form: Moulded Units, direct moulded on hand built or soles cut from sheet Normal Density Range: 1.05-1.35 Wear Resistance: Moderate-Excellent Hardness: Soft-moderately hard Crack Resistance: Good-excellent Slip resistance: Potentially very good, long life of tread pattern . In good quality material the tread is not limited by flex cracking consideration. Other Properties: Heat resistant, Oil resistant. Can be made electrically conductive Other Comments: Excellent multi-purpose soling in every respect. Can be compounded to suit requirements compounding and processing is expensive unless cutting out from sheet Typical usage: Nearly all footwear types including(all- moulded boots) industrial and other high performance products . Heel top pieces for Men’s formal shoes.

7. 6.Vulcanised Rubber (Cellular) Form: Closed cell ‘micro’ for moulded units, casters and sheet. Open cell ‘sponge’ for direct moulded midsole only. Normal Density Range: 0.3-1.1 Wear Resistance: Fair-moderate (Sponge not applicable) Hardness: Soft-medium Crack Resistance: Good Slip resistance: Moderate, limited tread life(sponge not applicable) Other Properties: Except sponge, expands on mould opening. Subsequent slight shrinkage (should be checked) Rubbery may be strong and enduring Other Comments: Except sponge, unit moulding to final size require accurate expansion prediction and fight process control . Die cutting from sheet or trimming casters is easier. Sponge rubber of similar density. Typical usage: Micro rubber; comfortable casual shoes, beach and poolside sandals. Sponge; slippers and work boots

8. 7.Eva(cross-linked ethylene vinyl acetate) Form: Microcellular moulded units, caster and sheet (closed cells) Normal Density Range: 0.2-0.4 Wear Resistance: Fair-moderate Hardness: Very Soft-Soft Crack Resistance: Generally excellent but more risk with thick units. Slip resistance: Modest when wet and without pattern, limited tread life. Other Properties: As vulcanized micro rubber above, but even lighter in weight and less pungent in smell. No sponge version Other Comments: As vulcanized micro rubber above. Ideal material for thick but light weight shock absorbing midsole. As on outside it is more durable than micro rubber of similar density. Typical usage: As vulcanized micro rubber above with the addition of the sport shoe midsole

9. 8.Thermoplastic Rubber(Compact/cellular) Form: In compact: Moulded units and moulded on In cellular: Moulded units and moulded on Normal Density Range: In compact: 0.9-1.1 In cellular: 0.8-1.0 Wear Resistance: In compact: Moderate good In cellular: fair good Hardness: In compact: Soft-Hard In cellular : S oft Crack Resistance: Good, better at low temperature Slip resistance: Potentially very good, but limits tread life. Rear heel needs careful design in soft compounds otherwise wet can be low. Other Properties: Very sensitive to oils and solvents. Stiff relative to its hardness. stiffer along the mould axis than across. High friction can melt the surface in vigorous use Other Comments: Rubbery aesthetics, popular as a cheaper and lighter alternative to solid vulcanized rubber, but not tough enough for sustained heavy duty use. Prone to from mould flow lines and thin coring ribs can collapse. Delamination sometimes a problem Typical usage: Casual and fashion footwear, children shoes, winter boots and slippers. (often with textile veneer)

10. 9.PVC( Plasticised -polyvinyl-chloride) Form: In compact: Moulded units and moulded on & sheet. In cellular: Moulded units and moulded on Normal Density Range: In compact: 1.15-1.35 In cellular: 0.7-0.9 Wear Resistance: In compact: Good-v. good In cellular: Good Hardness : In compact: Medium In cellular: Very soft-soft Crack Resistance: Satisfactory, but worse at high hardness or low temperature Slip resistance: Potentially very good with long life of tread pattern . Adversely affected by High hardness and low temperature Other Properties: Oils leach out normal plasticisers , embrittling the material. Special oils fat resistant versions available . Trends to wear very smooth. Other Comments: Easily moulded Good economical multipurpose soling. Usually appears quite glossy . Under pressure from environmentalist for perceived, if not actual risks. Tough performs best at low hardness. Typical usage: Most types of footwear including all- moulded boots, industrial footwear and jellies

11. 10.Polyurethane(Pu(reaction moulded )) Form: In compact: Moulded face on dual density soles In cellular: Moulded units, and moulded on and midsole for dual density Normal Density Range: In compact: 0.9-1.1 In cellular: 0.4-0.6 Wear Resistance: In compact: Excellent In cellular: Good. excellent Hardness: In compact: Soft medium In cellular: Very soft moderately hard Crack Resistance: Satisfactory , but sensitive to tread design and off ratio mixing Slip resistance: Potentially very good with long life of tread pattern. Any applied finish can affect initial performance but improves with wear, especially when cellular structure exposed Other Properties: Polyester version (closed cell) is oil resistant but vulnerable to hydrolysis. Polyether version (open cell) is hydrolysis resistant but usually oil resistant and may absorb water. Other Comments: The most durable of the low density solings , comparable with or better than many compact soles. Good set resistance and dimensional stability . Cellular mid sole can be used with compact outsole of PU, v.rubber or TPU. Typical usage: most types of footwear including all moulding oil- moulded boots and industrial foot wear . Useful in thicker soles where it can mimic cork/wood.

12. 11.Thermoplastic PU (compact) Form: Moulded units, and moulded facers of dual density soles Normal Density Range: 1.15-1.25 Wear Resistance: Excellent Hardness: Medium-very hard Crack Resistance: Good , including harder grades Slip resistance: Potentially good (softer grades) long life of tread pattern. H ard grades can be slippery, but this is less relevant in special application eg studded or spiked sports shoe Other Properties: Oil resistant versions available Other Comments: Material costs are expensive but performance and appearance are both very good. May be blended in any ratio with PVC. Typical usage: Studded or spiked soles, women’s fashion shoe top pieces (hard grades) industrial and premium casual footwear (soft grades).

13. 12.Thermoplastic PU (cellular) Form: Moulded units Normal Density Range: 0.7-1.0 Wear Resistance: Good-excellent Hardness: Medium Crack Resistance: Good Slip resistance: Potentially good long life of tread pattern Other Properties: Local density depends on proximity to injection point Other Comments: High material price which is only partly offset by expansion to medium density . A premium material offering good properties and appearance. Typical usage: Premium and casual shoes.

14. 13.Special Thermoplastic(Nylon , pebax & hytrel ) Form: Compact moulded units based on various Polymers Normal Density Range: 1.0-1.2 Wear Resistance: Not applicable Hardness: Very hard Crack Resistance: Satisfactory (where applicable) Slip resistance: Low due to high hardness but this is less relevant in special application Other Properties: Nylon: can wear to a sharp edge or burr. Pebax : good low temperature impact resistance, sensitive to hydrolysis. Hytrel : good low temperature properties and abrasion resistance. Other Comments: These offer thin stiff soles with flexing endurance for special application. Pebax and Hytrel are expensive compared to TPU Typical usage: Football boots, ski boots.