The difference between PU and PVC
The upper layer of PVC is paint, the main component in the middle is polyvinyl chloride, and the lower layer is back-coated adhesive.
PU is commonly known as synthetic leather and has a lighter specific gravity. The textures of PU are all paper textures, which is a process in which PU pulp is coated on textured release paper, and then the paper is peeled off after cooling and setting, thereby leaving the paper texture on the PU layer.
PU can also be post-processed and embossed. In terms of production technology, there are two types: wet method and dry method. The two are easily distinguished. The wet method is generally thicker because there is a layer of BASE (low foaming layer) between the surface layer and the base fabric, while the dry method does not have BASE and is applied directly to the base of the fabric, so it is thinner and the texture is easy to deform.
Wet PU is widely used in bags, handbags, shoes, balls, stationery, sofas, etc., while dry PU is mainly used in packaging and clothing.
Most people refer to synthetic leathers other than genuine leather, such as PVC and PU leather, as artificial leather or imitation leather. PVC and PU are both polyvinyl chloride (a type of plastic), but the manufacturing processes of these two products are different.
During the manufacturing process of PVC leather, plastic particles must be hot-melted and stirred into a paste, and then evenly coated on the T/C knitted fabric base according to the specified thickness, and then entered into a foaming furnace for foaming to make it adaptable We produce various products with different softness requirements, and perform surface treatment (dying, embossing, polishing, matting, grinding and fluffing, etc., mainly in accordance with specific product requirements) when they are released.
The manufacturing process of PU leather is more complicated than that of PVC leather. Since the base fabric of PU is a canvas PU material with good tensile strength, in addition to being coated on the base fabric, the base fabric can also be included in the middle to make it There is no base fabric visible from the outside. The physical properties of PU leather are better than PVC leather, including resistance to bending, good softness, high tensile strength, and breathability (not available in PVC). The pattern of PVC leather is hot-pressed by a steel pattern roller; the pattern of PU leather is hot-pasted on the surface of the semi-finished leather with a pattern paper, and then the paper leather is separated after it cools down to make the surface. deal with. The price of PU leather is more than double that of PVC leather, and the price of PU leather with certain special requirements is 2-3 times higher than that of PVC leather. Generally, the pattern paper required for PU leather can only be used 4-5 times before being scrapped; the pattern roller has a long service life, so the cost of PU leather is higher than that of PVC leather.
There are also certain differences in the scope of application of these two materials. In terms of footwear, PVC leather is mostly used in linings or non-weight-bearing parts, or in the manufacture of children’s shoes; PU leather can be applied to footwear fabrics or weight-bearing parts. In terms of bags, PVC leather is more suitable. This is because the items in the bag, unlike your feet in shoes, do not emit heat and do not bear your own weight.
The difference between PU and PVC is relatively easy. From the corners, the base fabric of PU is much thicker than that of PVC. There is also a difference in feel. PU feels softer; PVC feels harder; you can also use fire to burn it. The smell is much lighter than that of PVC
How to identify:
1. PU feels softer than PVC, has good quality and good toughness. It is generally used to make fabrics and can withstand relatively large tensile forces;
2. PU is more expensive than PVC;
3. PVC can be torn apart with force, but PU cannot;
4. PVC base fabrics are generally thinner and thinner; PVC mostly has water-knitted fabric bases and singlet fabric bases, while PU fabric bases are of higher quality; PVC leather bases are generally textile fabrics and knitted fabrics. The base of PU leather is non-woven fabric;
5. If burned with fire, PU will have a lighter smell, while PVC will turn black and smell bad.
6. The proportion of PVC is larger than that of PU.
7. The texture of PVC is deeper and the foaming layer in the middle is more obvious.
PU is divided into textures, including mirror PU, sheep grain PU, Nappa PU, two-color PU, cork grain PU, metal PU, Helen grain PU, litchi grain PU, pigskin grain PU, R61 grain PU, crocodile grain PU, fish scale grain PU , soft lines, etc. Mirror PU is characterized by a bright surface, including wrinkled mirror PU, crystal mirror PU, film mirror PU, etc. The textures of Nappa, Helen (KMF), metal, and R61 PU are relatively similar, and you have to look very carefully to distinguish them with the naked eye. The main reason is the difference in texture patterns. The two-color PU surface and base fabric are the same color. Look carefully at the R61 pattern, there are some small holes; the sheep pattern is a continuous small hole; the Nappa pattern is more regular and obvious; the rest is the KMF Helen pattern, the pattern has no fixed rules; soft pattern PU The texture is very light and light. There is also a kind of elastic PU, which has obvious elasticity. The surface of semi-PU is PU, and the base fabric is PVC. It is actually PVC and can be torn by hand. SemiPU is also called imitation PU.
1. Artificial leather is mainly divided into two types: imitation leather (or rubber) and high-grade PU. Imitation leather or rubber is the general term for artificial materials such as PVC and PU. It is made by foaming or laminating PVC and PU with various formulas on a textile cloth base or non-woven fabric base. It is characterized by a wide range of varieties, good waterproof performance, neat edges, high utilization rate and low price. It is cheaper than genuine leather. High-grade PU, the surface technology and the fiber structure of the base material almost achieve the effect of genuine leather, and its price is comparable to that of domestic first-layer leather.
During the manufacturing process of PVC leather, plastic particles must be hot-melted and stirred into a paste, and then evenly coated on the T/C knitted fabric base according to the specified thickness, and then entered into a foaming furnace for foaming to make it adaptable Produce various products with different softness requirements, and perform surface treatment (dyeing, embossing, polishing, matting, grinding) at the same time as they are released.�Fluffing, etc. are mainly carried out in accordance with specific product requirements).
The manufacturing process of PU leather is more complicated than that of PVC leather. Since the base fabric of PU is a canvas PU material with good tensile strength, in addition to being coated on the base fabric, the base fabric can also be included in the middle to make it There is no base fabric visible from the outside. The physical properties of PU leather are better than PVC leather, including resistance to bending, good softness, high tensile strength, and breathability (not available in PVC). The pattern of PVC leather is hot-pressed by a steel pattern roller; the pattern of PU leather is hot-pasted on the surface of the semi-finished leather with a pattern paper, and then the paper leather is separated after it cools down to make the surface. deal with. The price of PU leather is more than double that of PVC leather, and the price of PU leather with certain special requirements is 2-3 times higher than that of PVC leather. Generally, the pattern paper required for PU leather can only be used 4-5 times before being scrapped; the pattern roller has a long service life, so the cost of PU leather is higher than that of PVC leather.
PVC can be divided into soft PVC and hard PVC. Among them, hard PVC accounts for about 2/3 of the market, and soft PVC accounts for 1/3. Soft PVC is generally used for floors, ceilings and the surface of leather. However, because soft PVC contains softeners (this is also the difference between soft PVC and hard PVC), it easily becomes brittle and difficult to preserve, so its range of use is limited. Hard PVC does not contain softeners, so it has good flexibility, is easy to shape, not brittle, non-toxic and non-polluting, and has a long storage time, so it has great development and application value. Hereinafter, it is referred to as PVC. The essence of PVC is a vacuum plastic-absorbing film, which is used for surface packaging of various types of panels, so it is also called decorative film and adhesive film. It is used in many industries such as building materials, packaging, medicine, etc. Among them, the building materials industry accounts for the largest proportion, accounting for 60%, followed by the packaging industry, and several other small-scale application industries.
2. Synthetic leather (semi-PU leather)
Synthetic leather is a great leather substitute for winter leather jackets, but since synthetic leather is processed using TPU (polyurethane elastomer). TPU is very expensive, so many domestic manufacturers use PVC as a partial replacement. They do this: first coat the cloth base with PVC (artificial leather) and then coat it with TPU coating. In this way, the price can be greatly reduced, but the plasticizer in PVC will migrate out in less than a year, causing the synthetic leather (actually artificial leather) to become hard and brittle, so some customers buy new leather jackets for less than The edges become brittle and crack within a year. In fact, the factories that produce synthetic leather call it semi-synthetic leather or semi-PU leather.
Semi-PU leather can be identified using a very simple method, which is to heat copper wire on a fire until the color of the fire is red (no green), and the copper wire is also burning red in the fire. Remove the copper wire immediately Put it on the synthetic leather, and the synthetic leather will melt onto the copper wire. Finally, put the copper wire on the fire. If the fire is green at this time, it proves that there is PVC and it is semi-PU leather. If the fire is red, it proves that it is PU leather. This method is a simple method and can be used for general identification
3. Characteristics and differences between PVC and PU
PVC is an early substitute for leather fabrics invented. It is made of PVC plus plasticizers and other additives, calendered and compounded on cloth. The advantages are cheap, rich colors and various patterns. The disadvantages are that it hardens easily and Become brittle.
PU synthetic leather is used to replace PVC artificial leather, and its price is higher than PVC artificial leather. In terms of chemical structure, it is closer to leather fabrics. It does not use plasticizers to achieve soft properties, so it will not become hard or brittle. It also has the advantages of rich colors and various patterns, and is cheaper than leather fabrics. So it is welcomed by consumers.
The difference between PU and PVC is relatively easy. From the corners, the base fabric of PU is much thicker than that of PVC. There is also a difference in feel. PU feels softer; PVC feels harder; you can also use fire to burn it. The smell is much lighter than that of PVC.
PU is polyurethane, and PU leather is the epidermis of polyurethane. Nowadays, clothing manufacturers widely use this material to produce clothing, commonly known as imitation leather clothing. PU is the abbreviation of English ploy urethane, and the chemical name of polyurethane in Chinese is also good or bad in quality. Good bags Mostly imported PU leather is used;
PU leather is generally the second layer of leather with cowhide on the back. A layer of PU resin is coated on the surface, so it is also called film cowhide. Its price is cheaper and its utilization rate is high. With changes in technology, it has also been made into various grades, such as imported second-layer cowhide. Due to its unique technology, stable quality, and novel varieties, it is currently a high-end leather, and its price and grade are no less than first-layer genuine leather.
PU leather bags and genuine leather bags have their own characteristics. PU leather bags have beautiful appearance, are easy to take care of, and are relatively cheap, but are not wear-resistant and easy to break. Genuine leather bags are expensive and troublesome to take care of, but they are durable.
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