III. Leather
(1) Common types of cowhide
In the vast world of leather materials, cowhide holds an important place. The commonly used types of cowhide are rich and diverse, and each has its unique characteristics and uses.
Full-grain leather is a type of high-quality cowhide. It is usually taken from the outermost layer of the cowhide, featuring a smooth and delicate surface texture with clear and natural grain patterns, presenting the original appearance of the cowhide. This kind of cowhide is tough and durable, and is often used in making high-quality leather goods, leather shoes, etc., adding a noble and elegant touch to the products.
Buffed leather is cowhide that has undergone special buffing treatment. The buffing process gives it a unique appearance and tactile sensation. The surface is relatively smoother, and its gloss has also changed. Buffed leather has a soft texture and uniform color, making it suitable for creating some leather products that pursue a simple and fashionable style.
Second-layer cowhide is located in a specific position in the hierarchical structure of cowhide. Compared with the top layer of cowhide, its texture and characteristics are different. Second-layer cowhide has good toughness and is relatively affordable in price. It is often used in some leather products that require a certain degree of cost control while ensuring a certain quality.
NAPPY cowhide. This kind of cowhide is generally taken from calves. The leather surface is softer and more delicate, with fine pores, and it has excellent flexibility and comfort. Due to its unique texture, NAPPY cowhide is often used to make high - end fashion leather goods, baby products, etc., bringing people an ultimate tactile experience.
(2) Basic methods for testing cowhide
Inspecting the quality of cowhide is a crucial step in ensuring the quality of leather products. There are several simple yet effective methods that can help us distinguish the authenticity and quality of cowhide.
First is the burning method. When we take a small piece of cowhide and burn it with fire, if we smell a special burnt smell, similar to the smell of burning hair, it indicates that this is very likely to be real cowhide. This is because cowhide contains protein components, which are similar to those in hair, so it will produce this special odor when burned. Moreover, real cowhide is not easy to char during the burning process. This is because it has a certain fiber structure and toughness, enabling it to maintain a relatively stable state under the test of the flame.
Secondly, there is the blowing method. We can blow air against the bottom surface of the cowhide and then touch the leather surface with our hands. If we can feel the air passing through and the surface feels moist when touched, it indicates that the cowhide has good breathability. Real cowhide is a natural leather material with many tiny pores inside. These pores allow air to circulate within the leather, thus ensuring its breathability. This is also one of the important characteristics of high - quality cowhide.
Finally, the judgment of the quality of cowhide is mainly reflected in the following aspects:
Surface scars: The degree of damage to the leather surface is one of the important indicators for measuring the quality of cowhide. Cowhide with fewer surface scars indicates that it has suffered less damage during the growth or processing process, and its quality is relatively high. On the other hand, cowhide with more scars may affect the appearance and durability of leather products.
In the case of uniform thickness: The thickness of high-quality cowhide should be uniform. If there is a large difference in the thickness of the cowhide, it may result in different strength and durability in various parts when making leather products, affecting the overall quality of the products.
Leather feel: The sense of touch is an important way for us to intuitively assess the quality of cowhide. Good - quality cowhide feels soft, smooth and elastic, while inferior cowhide may feel rough, stiff and lack texture.
Special treatments for the surface and bottom: Special treatment methods such as sanding the surface and applying PU will change the appearance and performance of cowhide. Sanding the surface can make the cowhide surface smoother and flatter, while applying PU can enhance the wear resistance and water resistance of the cowhide. Different treatment methods are suitable for different product requirements, and we need to judge their advantages and disadvantages according to specific situations.
Effects of acid treatment on hardware: If cowhide is subjected to acid treatment during the processing, it will corrode the hardware. Therefore, when used in combination with hardware, the hardware must undergo acid-resistant treatment to ensure the quality and service life of the products.
(3) Specification calculation of cowhide
The specification calculation of cowhide is usually based on the volume calculation, which is due to the particularity of cowhide itself - its irregular shape. In the actual calculation process, the amount of waste needs to be determined according to the specifications of the actual cut pieces. Generally speaking, the waste rate is between 25% - 40%. This is because during the cutting process, a reasonable layout needs to be made according to the shape and texture of the cowhide to maximize the use of the material. However, due to its irregularity, there will always be some scraps that cannot be fully utilized, resulting in a certain amount of waste.
The formula for calculating the unit square foot is: Unit square foot = Length × Width ÷ 144. Through this formula, we can accurately calculate the volume of cowhide, providing an accurate basis for the material usage in the production of leather products.
(4) Attention details in the cowhide processing process
During the processing of cowhide, there are several details that need special attention.
Leather shaving is an important process. It can adjust the thickness of cowhide to make it more uniform, meeting the needs of different products. The precision of leather shaving directly affects the quality of leather products. If the leather is not shaved evenly, it may result in an uneven surface of the product, affecting its appearance and performance.
Edge oiling treatment can enhance the edge sealing and aesthetics of leather products. By applying special edge oiling materials to the edges of leather, it can prevent edge wear and thread loosening. Meanwhile, it makes the edges of the products smoother and neater, thus improving the overall quality.
Color modification involves adjusting the color of cowhide according to the design requirements of the product. During the color modification process, the uniformity and stability of the color need to be strictly controlled to ensure that the color of the cowhide after color modification meets the design requirements and that problems such as color fading do not occur during use.
(5) Usage of cowhide
Cowhide has a variety of uses in the production of leather products, providing rich possibilities for the design and functionality of the products.
Noodles. Here, "noodles" refer to long, thin strips made of cowhide, which are commonly used for the decoration and reinforcement of leather goods. They can add a delicate sense of lines to leather goods and enhance the overall aesthetic appeal of the products.
Front decorative LOGO: The LOGO made of cowhide in various shapes is used for the front decoration of leather goods. The cowhide LOGO has a unique texture and three - dimensional effect, which can highlight the brand image and product features.
Handle pieces. The handle pieces made of cowhide offer people a comfortable gripping experience. They not only need to have good wear resistance and comfort but also be coordinated with the overall style of the product.
Other accessory leather: Apart from the above common uses, cowhide can also be used as accessory leather material for various leather products. It is used to make components such as internal linings and pockets, providing all-round support and protection for the products.