Mastering PVC Leather: Understanding its Preparation, Structure,Properties and process
In modern material science and industrial production, synthetic leather is getting more and more attention and application.PVC artificial leather or PVC synthetic leather referred to as PVC leather,as a widely used synthetic leather material, has won the favor of the market with its unique performance and various application scenarios. In this paper, we will give you a systematic understanding of PVC leather from the aspects of preparation method, structure and performance, and post-treatment process.
Table of Contents
Methods of preparing PVC leather
PVC leather is a kind of imitation leather obtained by coating or laminating a mixture of polyvinyl chloride resin (PVC), plasticizer, stabilizer and so on onto a substrate. There are two main common preparation methods for this material:
Direct coating method
PVC plasticizing paste (a mixture of PVC resin and plasticizer-based paste) is coated on the pre-treated base cloth with a scraper, and then PVC leather is produced through the processes of gel plasticization, cooling and winding. This is the earliest and simplest process method, which can produce ordinary leather, foam leather, film leather and so on. Its advantages are high fastness of combination of base cloth and coating, simple equipment, low investment cost and high production efficiency. The disadvantage is that it needs a lot of emulsion resin, the fabric base cloth needs pretreatment, the product quality is not easy to control, and the plasticizing paste is easy to penetrate into the base cloth, thus leading to the finished product feel poor, can only be applied to the production of thin leather. Now the direct scraping and coating method is no longer the main production method.
Process flow of producing ordinary PVC artificial leather by direct scraping method
Calendering method
the base cloth is introduced in the process of calendering the soft PVC film, so that the film and the base cloth are firmly affixed together, and then made through post-processing (e.g. embossing, foaming, etc.). Calendering is the most important production process for PVC leather, especially suitable for the manufacture of bag leather, furniture leather and floor leather, but also for the production of garment leather and shoe leather. Its advantages are large processing capacity, fast production speed, good product quality, continuous production, and the base cloth used is very extensive. This is the tanning method used in our factory.
Process flow diagram of PVC artificial leather by calendering method
Main raw materials
- Resin: Resin is mostly used in suspension method SG3, SG4 resin. Foaming layer can choose SG5 with lower molecular mass, when producing oxford leather, it can be modified by adding rubber or rubber-like plastics with good elasticity and compatibility. Oxford leather products with modified resin have comfortable handfeel and rubbery appearance.
- Plasticizer: DOP and DBP are the main ones. When choosing plasticizers, two main points should be considered: First, the temperature is low during calendering, and plasticization is difficult, in order to ensure complete plasticization, the plasticizer with high efficiency should be chosen and the amount of main plasticizer should be increased, and the auxiliary plasticizer should not be used as much as possible. Secondly, the foamed artificial leather has to be heated twice in the calendering process and foaming process, so it is necessary to choose the plasticizer with small heat loss and low volatility.
- Heat stabilizers: heat stabilizers are mostly selected metal soap or composite liquid stabilizers, can also use organotin type. Selection should pay attention to the activation of the heat stabilizer on the foaming agent, can not make the decomposition temperature of the AC foaming agent is too low, so that the decomposition of the foaming agent occurs before it is not foamed.
- Foaming agent: Select AC foaming agent.
- Filler: fineness required is above 320 mesh.
- Lubricant: The function is mainly to prevent the melt from wrapping the rollers.
- Base cloth: Wide range available, such as flat cloth, canvas, knitted cloth and non-woven fabrics can be used.
- Typical formulations: Different products with different requirements will have different formula ratios. So you just need to tell us the requirements, we can develop the corresponding formula products.
Main production equipment
There are many equipment used in calendering method, and the equipment is huge and the production line is long. In the early stage, the base cloth treatment will use the roller coating machine, the resin screening will use the vibrating screen and the flat moving screen, the material mixing will use the high speed mixer, the later stage will use the vacuum suction pattern, embossing and printing machine to deal with the pattern and printing, of course, the main body of the production line is still calendering machine. Calendering method of PVC leather generally use four-roller calender, mainly has a transmission system, calendering system, roller heating system, lubrication circulation and cooling system and electronic control system.
Structure and Performance of PVC leather Revealed
The structure of PVC leather mainly consists of base fabric layer and PVC coating. The base fabric layer can be non-woven, woven or knitted fabric, etc., while the PVC coating is given diverse properties through different formulations and processes.
- Physical properties: PVC leather has excellent abrasion, tear and folding resistance, which makes it perform well in frequently used environments. In addition, PVC leather has outstanding waterproofness and weather resistance, which enables it to maintain its performance in a variety of climatic conditions. PVC is a typical linear polymer with relatively high polarity, hardness, rigidity, high dielectric constant and dielectric loss, and the PVC molecule also contains a large amount of chlorine, which gives it excellent flame retardant properties.
- Chemical properties: PVC leather has good resistance to acid, alkali, grease and other chemicals, which enables it to maintain its stability and appearance in environments with high chemical exposure. In addition, specially treated PVC leather can also have anti-bacterial, anti-mold and other functions, which further expands its application scope.
A Deep Dive into Post-Treatment Process of PVC Leather
The post-treatment process of PVC leather not only affects its performance, but also determines its appearance and texture. The following are several common processes:
- Printing process: By printing on the surface of PVC coating, various patterns and patterns can be made to meet the aesthetic needs of different consumers. For example, simulating the texture of natural leather and designing fashionable patterns can be realized through the printing process.
- Embossing process: By embossing the surface of PVC coating, different surface textures can be formed, which makes the artificial leather have more realistic touch and appearance. For example, PVC leather with special textures such as imitation crocodile skin and snakeskin are widely used in high-grade bags, furniture and other fields.
- Composite process: By compounding different materials together, artificial leather with multiple functions can be made. For example, the composite waterproof and breathable membrane makes the artificial leather both waterproof and breathable, which is widely used in outdoor products and sports goods.
- Vacuum suction texture process: Relying on the special breathable ceramic pattern wheel, combined with vacuum adsorption to generate negative pressure, the softened artificial leather-based material will be processed to form and shape the surface pattern. This is the main post-treatment process we use now. Vacuum suction texture products are soft to the touch and closer to the texture of genuine leather. The special ceramic wheel of vacuum suction texture machine has fine and clear texture, which improves the simulation of the product and is closer to the effect of real leather
Conclusion
With its excellent physical and chemical properties, various preparation methods and processes, PVC leather has become a favored synthetic leather material in the market. Whether it is used for furniture, garments, automobile interiors, or high-grade bags and outdoor products, PVC leather can satisfy the needs of different fields with its unique advantages. With the continuous progress and innovation of technology, PVC leather will show its potential and value in more applications. If you have any needs or questions about PVC leather, please feel free to contact us, we will provide you with professional consultation and service.Go to the homepage of website.