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UPPER LEATHERS IN SHOE MANUFACTURING

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Abstract

Based on the environmental condition that shoe will be used, it has to provide optimum comfort with use of high quality leather parts. Leather as a material is often chosen when considering clothing properties and used as upper, lining and insole material in shoe manufacturing. Especially lining and insole materials have quiet significant functions and could affect the health of foot and comfort of the wearer working under heavy conditions and may even increase their work efficiency. The selection of raw material should be considered according to the final purposes of shoe and new special or technological methods should be chosen instead of classic beam house processes. The absence of the leather product standards, based on the final product usage purposes, standard values have to be determined for the shoe upper leathers. As a result, the shoe upper leather used in different environment needs to be investigated in further scientific researches.
Bitlisli B., Adıgüzel Zengin A., Yeldiyar G., Kairanbekov G., Küçükakın E. Upper Leathers in Shoe Manufacturing
Journal of Industrial Technology and Engineering, 2013, 2(07): 37 - 41
37
UPPER LEATHERS IN SHOE MANUFACTURING
Bitlisli B.1, Adıgüzel Zengin A.1, Yeldiyar G.2, Kairanbekov G.2, Küçükakın E.1
1 Leather Engineering Department, Engineering Faculty, Ege University, Izmir, Turkey
2 M.Auezov South Kazakhstan State University, Shymkent, Kazakhstan
Е-mail: oral.bitlisli@ege.edu.tr
ABSTRACT
Based on the environmental condition that shoe will be used, it has to provide optimum
comfort with use of high quality leather parts. Leather as a material is often chosen when
considering clothing properties and used as upper, lining and insole material in shoe
manufacturing. Especially lining and insole materials have quiet significant functions and
could affect the health of foot and comfort of the wearer working under heavy conditions and
may even increase their work efficiency. The selection of raw material should be considered
according to the final purposes of shoe and new special or technological methods should be
chosen instead of classic beam house processes. The absence of the leather product standards,
based on the final product usage purposes, standard values have to be determined for the shoe
upper leathers. As a result, the shoe upper leather used in different environment needs to be
investigated in further scientific researches.
Key words: shoe manufacture, upper leather, structural strength, water absorption
properties, grain flexibility.
INTRODUCTION
The shoe is an item of apparel used by men all their life. Various types of footwear have
been developed considering different conditions of life and work. There are significant
differences between shoes used in our daily lives and those are manufactured for industrial,
agricultural, military, athletic and artistic purposes [1-3].
The parts of the shoes should be comfortable and not impede the rotation of the foot
considering the time that has been spent in shoes during the daily usage. A leather shoe
consists of many different parts such as shoe upper leather, lining, insole and sole which have
been produced in different manufacturing techniques and have different characteristic
properties (Fig. 1). These parts are composed of various leather types and each has a separate
role. The manufacturing of ideal leather shoe, produced by the combination of different
leather parts and auxiliary materials, might be possible by showing resistance to the impacts
occurred at either during manufacturing process or usage of the shoe [1, 4].
Shoe industry, used the 70% of the leather produced in worldwide, has a close
relationship with leather industry. Shoe, known as foot apparel, is mainly composed of upper,
sole and heel parts. In addition, many different parts can also be used in shoe production
depending on the age, sex, and fashion factors. Shoe upper, consists of upper leather and
lining, is the outer layer of the shoe, which expose to the continuous bending movement 6.
Therefore, shoe upper materials are needed to be produced lighter than the sole of the shoe.
For this purpose, upper leathers are widely used in production of shoes due to the positive
effect on the shoe comfort and foot health [2, 4].
Bitlisli B., Adıgüzel Zengin A., Yeldiyar G., Kairanbekov G., Küçükakın E. Upper Leathers in Shoe
Manufacturing
38
Journal of Industrial Technology and Engineering, 2013, 2(07): 37 - 41
Fig. 1. Parts of the shoes [5]
Upper leathers are commonly used in shoe manufacturing in that they have
demonstrated positive results regarding foot health and foot comfort. Comfort related to a
leather shoe can be explained in terms of a comfort provided by the structural formation of the
leather together with its various physical and chemical properties. This comfort in the shoe is
supported by a high-level water vapour permeability of the leather as well as its ability to
absorb the dampness inside the shoe without giving a feeling of wetness to the user. The water
vapour permeability and water absorption properties which upper leathers possess are of great
significance [2, 4].
MATERIALS AND METHODS
Classification of Upper Leathers [4]
RESULTS AND DISCUSSION
The General Properties of Upper Leathers [1, 2, 4, 6].
The properties of upper leathers used in high quality shoe manufacturing are indicated
as below;
1. Based on the shoe type;
For men : 1.2-1.4 mm
For women : 0.8-1.0 mm
For Boot: 1.0-1.6 mm
Top Boot: 1.0-1.2 mm for women,
1.4-1.6 mm for men
Sport shoes, Heavy sport shoes : 2.8
mm
For bags : 1.2-1.4 mm
2. Based on the finishing process;
Full grain
Corrected grain
Splitted leather
Nubuck- Sued
Patent leather
Softy
Waxy leather
Bitlisli B., Adıgüzel Zengin A., Yeldiyar G., Kairanbekov G., Küçükakın E. Upper Leathers in Shoe Manufacturing
Journal of Industrial Technology and Engineering, 2013, 2(07): 37 - 41
39
1. Structural Strength: The most important factor on the leather quality is the strength
of the leather to the external influences. Poor tensile, tear and stitch tearing strength are the
well indication of poor structural strength of leather material. Upper leather products should
demonstrate high tensile and tear strength values with extension in certain limits.
Additionally, the structural properties could vary depending on leather type and tanning
method.
2. Flexibility: The bending and flexion properties of leather materials, which will be
used in shoe manufacturing, are required to be high and compatible. Therefore, the leathers
with poor flexibility values show folding and breaking parts. Insufficient fatliquoring, non-
uniform tanning could be the reason of this undesired flexibility as well as the inadequate
removal of globular proteins between the collagen fiber bundles.
3. Grain Flexibility: If the grain flexibility is less than the leather (corium) flexibility,
grain cracks even split areas could be occurred during the molding process of the shoe
manufacturing.
4. Resistance to Water: Leather has a water absorption property because of its
structural property. However, water absorption characteristic is accepted as a normal property
up to some certain limits and extreme values can affect the leather quality negatively. The
wetting capability of leather grain is depended on the external surface tension and the grain
characteristic of leather. In this respect, the current condition of leather and the circumstances
have played an important role. The high water absorption property of leather is a well-known
undesired property and the shoe upper leathers should be processed as water repellent.
5. Water Vapour and Air Permeability: Water vapour and air permeability have
played an important role to determine the hygienic property of shoe upper leathers. Leathers
used both in garment and shoe production, should have the water vapour and air permeability
characteristics to some extent. Human body has the ability of holding the body temperature
stable and spreading it to the environment. Apparel covering the human body especially the
foot should be suitable for the cooling mechanism of the body. Especially, the heat, rose due
to the movement of the body during the work life, should have thrown out by the apparel.
However, if any difficulty is occurred during the heat transfer by evaporation, a discomfort
could be felled. For this reason, the leather types used in shoe manufacturing needed to be
precise according to clothing physiology.
6. Perspiration Fastness: High perspiration fastness value is desired by the shoe
manufacturers. In resting moment one foot excretes 72 ml sweat per day. The sweat shows
slightly acidic character when it is fresh and the pH of the sweat is changed in a range of 5.2-
7.0. The acidic character of the fresh sweat is slightly changed into alkali due to the urease
enzyme and the pH is increased up to 9. Thus, vegetable tanning materials are influenced by
urea which leads to breakdown the linkages between tanning materials and collagen fibers.
Besides, the alkalinity, occurred due to the breakdown of sweat, plays more important role
because especially the color of the vegetable tanned leathers could turn more dark colors
especially at the contacting area of sweat and vegetable tanned leathers.
7. Resistance to High and Low Temperature: Based on the environmental conditions
of use, shoes have to be the resistance to low and high temperatures. Countries all over the
world do not have the same environmental conditions and this fact playing an important role
on the temperature resistance of shoes. This feature can be given by special chemicals during
the beam house processes of the skins.
8. Resistance to Liquid and Oils: Similarly to the temperature resistance,
environmental conditions could be affected on leather properties. Affinity to oils should be
low to prevent the formation of stains which also provide the cleaning of the shoes more
easily. For this purpose, special chemicals can be applied during the production of skins
converting into leather.
Bitlisli B., Adıgüzel Zengin A., Yeldiyar G., Kairanbekov G., Küçükakın E. Upper Leathers in Shoe
Manufacturing
40
Journal of Industrial Technology and Engineering, 2013, 2(07): 37 - 41
9. Resistance to Sharp Objects: The shoe upper leathers especially the military shoes
and boots have to be resistance to sharp objects. The fiber stiffness and collagen structure
have an important role on the resistance to sharp objects.
10. The Amount of Water-Soluble Substances: Tanning minerals, lubricants, salts
and glucose cause unpleasant stains on the leather surface due to their insufficient removal
during the leather process and the salts like magnesium sulphate is known as the main reason
of the salt stain. Except from the stains, grain cracks can also occurred on the leather surface
and this type of stains can easily remove with effective washings.
11. Dyeing and Finishing Fastness: Finishing step is the final make-up of the leather.
Mostly finishing mixtures are compatible with base color. The quality of the finishing
property is determined by dry/wet rub fastness, light fastness and, the test for adhesion of
finish and these fastnesses can be increased by the use of proper chemicals.
Table 1. Quality requirements for shoe upper leathers [7]
CONCLUSION
Shoes are mostly effective clothes to determine the human comfort during the daily
usage. Based on the environmental condition that shoe will be used, it has to provide optimum
comfort with use of high quality leather parts.
Quality indicators, %
(Leather testing methods)
Main types of leather (General data)
Box
calf
Corrected
grain side
Glazed
kid
Water
proof
(comb.
tanned)
Water
proof
(chrome
tanned)
Sulfate ash %
Max 2% above the content of tanning oxide
Chromium oxide content,
%
>2.5
>2.5
>2.5
>1.2
>2.5
Fatty substances %
3-8
5-16
4-8
<16
8-15
Loss by washing %
<2.0
<2.0
<2.0
<2.0
<2.0
Degree of tannage
-
-
-
>30
-
pH (1:20)
Aqueous extract more than pH 3.5
Tensile strength N/mm2
≥20
>20
>20
>25
>25
Elongation at break %
>40
>40
>40
>40
>40
Elongation in % at 2
N/mm
≤14
<14
<14
<16
<14
Split tear force N/mm
>40
>25
>25
>50
>50
Stitch tear strength N
>80
>80
>80
>100
>120
Water penetration in min
(penetrometer)
≥60
>20
>20
>180
>120
Water absorption after 60
min
<20
<30
<30
<20
<25
Water absorption
Kubelka after 2h
<60
<60
<60
<30
<30
Water absorption
Kubelka after 24h
<85
<85
<85
<40
<40
Grain distension
(Lastometer), mm
≥7.0
≥7.0
≥7.0
≥7.0
≥7.0
Bitlisli B., Adıgüzel Zengin A., Yeldiyar G., Kairanbekov G., Küçükakın E. Upper Leathers in Shoe Manufacturing
Journal of Industrial Technology and Engineering, 2013, 2(07): 37 - 41
41
Leather as the material is often chosen when considering clothing properties and used as
upper, lining and insole in shoe manufacturing. Especially lining and insole materials have
quiet significant functions and could affect health of foot and comfort of the wearer working
under heavy conditions and may even increase their work efficiency. For this aim, following
conclusions have been made:
1. The selection of raw material should be considered according to the final purposes of
shoe and new special or technological methods should be chosen instead of classic beam
house processes.
2. The special production recipes have to be prepared, and chemicals that used on these
recipes should not interfere and not to decompose with each other.
3. In addition, clothing physiology, foot hygiene, chemical and physical fastness should
be determined by physical tests.
3. The absence of the leather product standards, based on the final product usage
purposes, standard values have to be determined for the shoe upper leathers.
As a result, shoe upper leather used in different environment, needs to be investigated in
further scientific researches.
REFERENCES
1 Bitlisli B.O., Sari Ö. Problems Stemming from Upper Leathers in Military Shoes and
Boots and Suggested Solutions. Infantry 2000 Symposium CD, Tuzla Infantry Cadet School
Command. Istanbul, 2000.
2 Bitlisli B.O., Karavana H.A., Başaran B., Aslan A. Importance of Using Genuine
Leather in Shoe Production in Terms of Foot Comfort. Journal of the Society of Leather
Technologists and Chemists, 2004, vol. 89, 107 p.
3 Sari Ö., Bitlisli B.O. Sole Leather Production in Turkey and Evaluation of its Quality
Levels. II National Shoe And Side Industry Symposium Papers, Konya Chamber Of Commers.
Konya, 1996, pp. 94-106.
4 Bitlisli B.O. Technology of Shoe Upper Leathers. Lecture Notes. Leather
Engineering Department, Engineering Faculty, Ege University. Izmir, 2013.
5 http://dancingfeet-jfaeth.blogspot.com/ (accessed 01.07.2010)_archive.html, If The
Shoe Fits - A Guide To Dance Shoes (accessed 18.06.2013.)
6 Howie I. Competing Materials in Shoemaking. Leather Int’l., 1995, pp.41-43.
7 BASF, Pocket Book, Test Methods, Leather Testing Methods, p.242.
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... High perspirati on fastness value is desired by the shoe manufacturers. In a resti ng state one foot excretes 72 ml of sweat per day [1]. The sweat shows slightly acidic character when it is fresh and the pH of the sweat is changed in a range of 5.2-7.0. ...
... The aim of the study is to evaluate the diff erent properti es of shoe leathers collected from randomly selected footwear and leather industries in Bangladesh. From the previous research [1,5,11,19], it has been found that there were several studies about either strength properti es or comfort properti es of shoe leather, while overall performance of shoe sustain the world market, Bangladesh has to give special attention to the quality and cost. The aim of the study is to evaluate the different properties of shoe leathers collected from randomly selected footwear and leather industries in Bangladesh. ...
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... Shoes are an essential item of apparel used in our everyday life. Various types of footwear have been developed, considering different conditions of life and work [1]. There are significant differences between shoes used in our daily lives and those that are manufactured for industrial, agricultural, military, athletic and artistic purposes [2][3][4]. ...
... High perspirati on fastness value is desired by the shoe manufacturers. In a resti ng state one foot excretes 72 ml of sweat per day [1]. The sweat shows slightly acidic character when it is fresh and the pH of the sweat is changed in a range of 5.2-7.0. ...
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Problems Stemming from Upper Leathers in Military Shoes and Boots and Suggested Solutions
  • B O Bitlisli
  • Ö Sari
Bitlisli B.O., Sari Ö. Problems Stemming from Upper Leathers in Military Shoes and Boots and Suggested Solutions. Infantry 2000 Symposium CD, Tuzla Infantry Cadet School Command. Istanbul, 2000.
Sole Leather Production in Turkey and Evaluation of its Quality Levels. II National Shoe And Side Industry Symposium Papers, Konya Chamber Of Commers
  • Ö Sari
  • B O Bitlisli
Sari Ö., Bitlisli B.O. Sole Leather Production in Turkey and Evaluation of its Quality Levels. II National Shoe And Side Industry Symposium Papers, Konya Chamber Of Commers. Konya, 1996, pp. 94-106.
)_archive.html, If The Shoe Fits-A Guide To Dance Shoes
  • B O Bitlisli
Bitlisli B.O. Technology of Shoe Upper Leathers. Lecture Notes. Leather Engineering Department, Engineering Faculty, Ege University. Izmir, 2013. 5 http://dancingfeet-jfaeth.blogspot.com/ (accessed 01.07.2010)_archive.html, If The Shoe Fits-A Guide To Dance Shoes (accessed 18.06.2013.)
  • I Howie
Howie I. Competing Materials in Shoemaking. Leather Int'l., 1995, pp.41-43.
Technology of Shoe Upper Leathers
  • B O Bitlisli
Bitlisli B.O. Technology of Shoe Upper Leathers. Lecture Notes. Leather Engineering Department, Engineering Faculty, Ege University. Izmir, 2013.