This document summarizes 13 different types of sole materials and their characteristics. It describes the form, density range, wear and crack resistance, hardness, slip resistance, and other properties. It also provides typical usage examples for each material type. The materials include leather, leather fiber board, resin rubber, crepe rubber, vulcanized rubber, EVA, thermoplastic rubber, PVC, polyurethane, thermoplastic PU, special thermoplastics like nylon, Pebax and Hytrel.

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

4. 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

6. 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,

8. 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

10. 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.

11. 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

13. 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

15. 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: Soft
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)

17. 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

19. 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.

21. 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. Hard 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).

22. 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.

24. 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.