In the daily inspection, we often encounter artificial leather and synthetic leather fabrics. However, there is no relevant identification method standard or accurate definition in China at present, so there is no accurate basis for issuing the report, and we can only judge by experience or habit, thus causing confusion in identification. Therefore, it is very necessary to determine the reasonable classification principle of synthetic leather and artificial leather before the relevant identification method standards are issued.

Definition and classification in relevant domestic standards and documents

1.1 definition and classification in relevant domestic standards

At present, there are about a dozen domestic standards related to synthetic leather and artificial leather. The definition and classification methods are mainly based on the base material, coating material and production process. See Table 1 for details. Among these standards, only gb21902-2008 [1] has clear definitions for artificial leather and synthetic leather [1-12].

Synthetic leather: refers to a kind of material with the appearance of natural leather that forms a polyurethane resin film layer or similar leather structure on the base cloth of woven cloth, non-woven cloth (non-woven cloth), leather and other materials by artificial synthesis; Artificial leather: refers to a kind of material with the appearance of natural leather, which is formed by artificial synthesis on the base cloth (including no base cloth) made of woven cloth, non-woven cloth (non-woven cloth) and other materials to form a film layer of polyvinyl chloride and other resins or a structure similar to leather.

From the definition only, it can be basically considered that the coating material of synthetic leather is polyurethane resin, and the coating material of artificial leather is polyvinyl chloride and other resins. However, the "polyvinyl chloride synthetic leather" appearing in the standard "3.3 characteristic production process and device" is contrary to this conclusion. At the same time, in other relevant standards, the base materials, coating materials and production methods of artificial leather and synthetic leather intersect with each other, and there is no clear classification principle. Only in relevant light industry standards, synthetic leather is coated with polyurethane resin, while synthetic leather is coated with PVC or polyurethane resin.

Main differences between synthetic leather and artificial leather in relevant domestic standards

1.2 definition and division in relevant domestic documents

In China, people used to call the artificial leather produced with polyvinyl chloride (PVC) resin as PVC artificial leather (hereinafter referred to as artificial leather); The artificial leather produced by polyurethane (PU) resin and traditional fabric is called Pu artificial leather (PU leather for short); The artificial leather produced by PU resin and nonwoven fabric is called PU synthetic leather (synthetic leather for short). This is the classification of synthetic leather and artificial leather in some literatures [13-16]. The classification is mainly based on coating materials and base materials: synthetic leather with polyurethane resin as coating material and nonwoven fabric as base cloth, and artificial leather with PVC or polyurethane resin as coating material and traditional fabric as base cloth. However, this classification method is quite different from the definition or classification in relevant standards.

Another representative classification method in the literature is the artificial leather and synthetic leather professional committee of China Plastics Processing Industry Association. According to the different raw materials, the artificial leather and synthetic leather are divided into PVC synthetic leather and PU synthetic leather. See Table 2 [17] for details. The classification method is basically the same as the definitions of artificial leather and synthetic leather in gb21902-2008. There is also no great difference between the definition or classification of other relevant standards. Classification of artificial leather and synthetic leather in relevant literatures.

Therefore, the current classification principle of synthetic leather and synthetic leather should be based on the definition of synthetic leather and synthetic leather in gb21902-2008, and refer to the classification method of synthetic leather and synthetic leather professional committee of China Plastics Processing Industry Association. According to the different raw materials, synthetic leather and synthetic leather are divided into PVC synthetic leather and PU synthetic leather. That is, PU synthetic leather with polyurethane resin as coating material and PVC artificial leather with PVC resin as coating material.