Detailed Explanation of Shoe Upper Materials

Suitable properties for shoe upper materials include: soft touch, breathability to dissipate moisture and absorb air, high recovery and elasticity, lightweight, wear-resistant, water-resistant, easy to process, and non-fading.

 

1. Natural Leather/Genuine Leather

There are many types of natural leather, with cowhide being the most commonly used, and sheepskin and pigskin also being used to a lesser extent. Over 80% of shoe uppers are made of cowhide. Natural leather generally offers advantages such as softness, good breathability, warmth, foldability, and durability.

 

Top-grain cowhide, also known as pearl leather, has a grainy surface with natural scars and vein marks. It is composed of a dense, thin dermis layer and tightly connected fiber layers. The fiber structure is relatively tight, and it possesses excellent strength, elasticity, breathability, and processability.

Split leather, also known as split leather, is obtained by splitting it using a splitting machine. This layer has a looser fiber structure and is then sprayed with chemical paint or coated with PVC or PU film. It maintains a certain degree of elasticity and plasticity, but its strength is relatively low.

Suede, also known as suede, has a surface that resembles original animal skin, with a hairy, rough texture, good breathability, a soft feel, and comfort. It can be dyed in a variety of colors. However, it has poor color fastness, is easily soiled, and is difficult to maintain. When designing shoes, avoid pairing suede with contrasting materials, as this can easily cause color bleeding.

 

2. Artificial Leather

Suede is made by foaming or laminating PVC, PU, or other materials of various formulations onto a textile or non-woven base. It is manufactured to meet varying strength, color, gloss, and pattern requirements. It offers a wide variety of patterns, excellent waterproofing, neat edges, high yield rates, and a relatively low price.

 

3. Mesh
Used in exposed shoe areas, it's lightweight and breathable, soft, comfortable, and flexible. However, its disadvantage is that it doesn't provide warmth. An example is sandwich mesh. Mesh's lightweight and breathable properties make it suitable for running shoes, training shoes, and other surface materials.

 

4. Foam
Foam offers excellent elasticity, light weight, rebound, and flexibility. It's commonly used in the collar, heel, and tongue for added comfort. Some shoe designs also use 2mm foam inside the waistband, adding comfort and breathability, while also enhancing the waistband's three-dimensional effect.

Due to its poor abrasion and tear resistance, foam is typically not used in exposed shoe surfaces. Instead, it needs to be laminated to other materials. It's usually coated with self-adhesive tape and then attached with a release liner. Lamination to other components is quick and easy, simply by removing the release liner.

 

5. TPU

A hard yet easily bendable plastic material with excellent support and protection. It is primarily used on various shoe uppers to provide enhanced support.

 

How to distinguish natural leather from artificial leather:
Genuine leather refers to natural leather processed from animal hides. Artificial leather refers to synthetic leather, a product synthesized from basic chemical raw materials. The structure of natural leather is extremely complex, making it impossible to produce it perfectly.

 

1. Natural leather has irregular shapes and uneven thicknesses. It may have some natural surface defects, varying degrees of surface smoothness and fineness, and is generally loose at the edges and belly. Full upper leather has noticeable pores and patterns, and the lining is generally fuzzy. Synthetic leather, on the other hand, has uniform thickness, a smooth surface, and no natural defects. Its pores and patterns are also uniform, and the lining is generally fuzz-free.

 

2. Finished leather with a uniform surface texture, no scratches, no rough lines, and no defects may be artificial leather. Natural leather has many deep, slightly slanted pores, while leather with shallow, vertical pores may be synthetic leather with a modified upper. From a cross-section, the fibers of natural leather have their own unique characteristics, with varying thicknesses in each layer. In contrast, the fibers of synthetic leather are essentially uniform across the layers, with a plastic film-like surface.

 

3. Natural leather is obviously highly absorbent, while synthetic leather is likely synthetic.

 

4. Natural leather has excellent elasticity and tensile strength, while synthetic leather is likely synthetic.

 

5. Blowing on the reverse side of the leather with saliva, if leakage occurs on the reverse side, this is due to the "anti-rebound" properties of genuine leather. Genuine leather is effective in keeping out cold and is also very breathable.

 

6. On the surface of natural leather, patterns and pores are visible, but their distribution is uneven. Animal fibers are visible on the reverse side. In a side section, the layers are clearly discernible, with the lower layer containing animal fibers. Scratching with a fingernail will cause the leather fibers to stand up, creating a fuzzy feel, and a small amount of fibers may fall off. If this is the case, it is synthetic leather.

 

7. Genuine leather has a very elastic feel. Bend the leather face downward about 90 degrees, and it will naturally wrinkle. The thickness and number of the wrinkles produced by bending different parts of the leather will vary significantly.

 

8. Natural leather has a strong, furry odor, which is still noticeable even after treatment. Artificial leather, on the other hand, has a plastic smell, not a furry smell.

 

9. Natural leather emits a burnt hair odor when burned, and the resulting ashes are generally easy to break into powder. Artificial leather, on the other hand, burns with a strong flame, shrinks rapidly, and has a very unpleasant plastic smell. It becomes sticky after burning and hardens into lumps after cooling.

 

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