PU is the abbreviation of English poly urethane, the chemical Chinese name "polyurethane". PU leather is the skin of polyurethane components. Widely used in luggage, clothing, shoes, vehicles and furniture decoration.
Pu leather is a kind of synthetic leather, its composition mainly includes the following aspects:
1. Substrate: Generally use fiber cloth, fiber film and other materials as the underlying material to improve the strength and durability of Pu leather.
2. Emulsion: The selection of synthetic resin emulsion or natural emulsion as a coating material can improve the texture and softness of Pu leather.
3. Additives: including plasticizers, mixtures, solvents, ultraviolet absorbers, etc., these additives can improve the strength, durability, water resistance, pollution resistance and UV resistance of Pu leather.
4. Astringent media: Astringent media is generally an acidifier, used to control the pH value of Pu leather, in order to facilitate the combination of coating and substrate, so that Pu leather has a better appearance and life.
The above are the main components of Pu leather, compared with natural leather, Pu leather can be more lightweight, waterproof and relatively cheap, but the texture, permeability and other aspects are slightly inferior to natural leather.
In China, people are used to using PU resin as raw materials to produce artificial leather called PU artificial leather (referred to as PU leather); Artificial leather produced with PU resin and non-woven fabric as raw materials is called PU synthetic leather (referred to as synthetic leather). It is customary to refer to the above three kinds of leather as synthetic leather. How do you name it? It needs to be unified and standardized to give it a more appropriate name.
Artificial leather and synthetic leather are an important part of the plastic industry and are widely used in various industries of the national economy. Artificial leather, synthetic leather production in the world has more than 60 years of development history, China began to develop and produce artificial leather since 1958, it is the earliest development in China's plastic industry industry. In recent years, the development of China's artificial leather and synthetic leather industry is not only the growth of equipment production lines of production enterprises, product output growth year after year, varieties and colors increase year after year, but also the development of the industry has its own industry organization, there is considerable cohesion, which can put China's artificial leather and synthetic leather enterprises, including related industries organized together. Developed into an industry with considerable strength.
Following PVC artificial leather, PU synthetic leather after more than 30 years of dedicated research and development by scientific and technological experts, as an ideal substitute for natural leather, has achieved breakthrough technological progress.
PU coated on the surface of the fabric first appeared in the market in the 1950s, and in 1964, the United States DuPont company developed a PU synthetic leather for the upper. After the Japanese company established a set of production lines with an annual output of 600,000 square meters, after more than 20 years of continuous research and development, PU synthetic leather has been rapidly growing in product quality, variety, or output. Its performance is getting closer and closer to natural leather, and some properties even exceed natural leather, reaching the degree of true and false with natural leather, occupying a very important position in human daily life.
Today, Japan is the largest producer of synthetic leather, and the products of several companies such as Coroli, Teijin, Toray, and Bell Textile basically represent the level of international development in the 1990s. Its fiber and non-woven fabric manufacturing is developing towards ultra-fine, high-density and high non-woven effect. Its PU manufacturing toward the direction of PU dispersion, PU water emulsion, product application field continues to expand, from the beginning of shoes, bags to clothing, ball, decoration and other special application fields, throughout all aspects of People's Daily life.
Artificial leather
Artificial leather is the earliest invention for leather fabric substitute, it is made of PVC plus plasticizer and other additives rolled composite on the cloth, the advantage is cheap, rich color, a variety of patterns, the disadvantage is easy to harden, brittle. PU synthetic leather is used to replace PVC artificial leather, its price is higher than PVC artificial leather. From the chemical structure, it is closer to the leather fabric, it does not use plasticizers to achieve soft properties, so it will not become hard, brittle, and has the advantages of rich color, a wide variety of patterns, and the price is cheaper than the leather fabric, so it is welcomed by consumers.
There is another kind of PU leather, generally the opposite side is the second layer of leather, coated with a layer of PU resin on the surface, so it is also called film leather. Its price is cheaper and the utilization rate is high. With the change of the process is also made into various grades of varieties, such as imported two layers of leather, because of the unique process, stable quality, novel varieties and other characteristics, for high-grade leather, the price and grade are no less than the first layer of leather. PU leather and real leather bags have their own characteristics, PU leather bags look beautiful, easy to take care of, low price, but not wear-resistant, easy to break; Real leather is expensive and troublesome to care for, but durable.
Leather fabric and PVC artificial leather, pu synthetic leather with two ways to distinguish: first, the degree of softness of the skin, leather is very soft, pu is hard, so most of pu are used in leather shoes; The second is to use the method of burning and melting to distinguish, the method is to take a small piece of fabric on the fire, the leather fabric will not melt, and PVC artificial leather, PU synthetic leather will melt.
The difference between PVC artificial leather and PU synthetic leather can be distinguished by the method of soaking in gasoline, the method is to use a small piece of fabric, put it in gasoline for half an hour, and then take it out, if it is PVC artificial leather, it will become hard and brittle, if it is PU synthetic leather, it will not become hard and brittle.
Natural leather because of its excellent natural characteristics are widely used in the production of daily necessities and industrial products, but with the growth of the world population, human demand for leather doubled, a limited number of natural leather has long been unable to meet people's needs. In order to solve this contradiction, scientists began to research and develop artificial leather and synthetic leather decades ago to make up for the lack of natural leather. The historical process of more than 50 years of research is the process of artificial leather and synthetic leather challenging natural leather.
Scientists began by studying and analyzing the chemical composition and organizational structure of natural leather, starting with nitrocellulose linoleum, and entering PVC artificial leather, which is the first generation of artificial leather. On this basis, scientists have made many improvements and explorations, first of all, the improvement of the substrate, and then the modification and improvement of the coating resin. By the 1970s, the non-woven fabric of synthetic fiber appeared needling into mesh, bonding into mesh and other processes, so that the base material has a lotuslike section, hollow fiber, to achieve a porous structure, and meet the network structure requirements of natural leather; At that time, the surface layer of synthetic leather has been able to achieve a micro-porous polyurethane layer, which is equivalent to the grain surface of natural leather, so that the appearance and internal structure of PU synthetic leather is gradually close to the natural leather, other physical properties are close to the index of natural leather, and the color is more bright than natural leather; The folding resistance at room temperature reaches more than 1 million times, and the folding resistance at low temperature can also reach the level of natural leather.
The emergence of microfiber PU synthetic leather is the third generation of artificial leather. The non-woven fabric of its three-dimensional structure network creates the conditions for synthetic leather to catch up with natural leather in terms of substrate. This product, combined with the newly developed PU slurry impregnation with open cell structure and the processing technology of composite surface layer, exerts the huge surface area and strong water absorption of the microfiber, making the ultra-fine PU synthetic leather have the inherent moisture absorption characteristics of the natural leather of the bundle of ultra-fine collagen fiber, so that no matter from the internal microstructure, Or the appearance of the texture and physical characteristics and people's wearing comfort, can be comparable to high-grade natural leather. In addition, the microfiber synthetic leather exceeds the natural leather in chemical resistance, quality uniformity, large-scale production and processing adaptability, waterproof, anti-mildew and other aspects
Practice has proved that the excellent properties of synthetic leather can not be replaced by natural leather, from the domestic and foreign market analysis, synthetic leather has also replaced a large number of natural leather with insufficient resources. The use of artificial leather and synthetic leather to do bags, clothing, shoes, vehicles and furniture decoration, has been increasingly recognized by the market, its wide range of applications, the number of large, many varieties, is the traditional natural leather can not meet.
Post time: Mar-29-2024