With the process of international market integration, the high quality and low pollution of products will be increasingly elevated to a certain level. With the joint research and development of numerous scientific research institutions in our country and the continuous intervention of technology-based enterprises, various high-performance synthetic leather water-based PU resins will inevitably become mainstream products, ultimately replacing solvent based products. Therefore, the research on water-based PU resin for synthetic leather needs to be continuously deepened.
1. Waterborne PU resin should reflect diversity, functionality, and fashionability
The development history of synthetic leather industry in China is less than 15 years. Due to the diversified, functional and fashionable characteristics of synthetic leather products, the development is very rapid, with dozens of new varieties being introduced to the market on average every year. Therefore, water-based PU resin must adapt to the development pace of synthetic leather.
Diversification requirements: Currently, synthetic leather products have been applied to various fields of people's daily lives, such as shoe leather, clothing leather, luggage leather, sofa leather, glove leather, automotive leather, etc. The diversity of synthetic leather products is very obvious. These synthetic leathers from different fields have varying properties, therefore, corresponding water-based PU resins are necessary to adapt to them.
Functional requirements: Leather products from different fields or within the same field have different performance characteristics, which is the differentiation of varieties, reflected in the different functional requirements of leather products. For example, shoe leather needs to be wear-resistant and resistant to acid and alkali, but light colored leather also needs to be resistant to yellowing; Clothing leather not only needs to be soft at low temperatures, but also needs to have the same hand feel and breathability as genuine leather; Home leather needs to be wear-resistant and dirt resistant, as well as fire-resistant and flame-retardant. Different synthetic leathers have different functional characteristics, and the vast majority rely on functionalization of waterborne polyurethane to achieve them.
Fashion requirement: At least tens or hundreds of synthetic leather products are introduced to the market each year. Some synthetic leather products are refurbished once a year, while others are refurbished almost every year or quarter, just like women's handbags, which are constantly changing and highly fashionable. So the development of water-based PU resin must also follow this trend, survive in change, and develop in change.
2. Water based PU resin should have a common price advantage
In theory, water-based PU resin should have a price advantage over solvent based PU resin. Therefore, exploring low-cost and high-quality water-based PU resin has always been the theme of research and development. This can be approached from the following four aspects:
One is to further screen the raw materials for synthetic resin, select cost-effective raw materials, and apply them to the resin production process. For example, the current price of TDI (toluene isocyanate) raw material has risen sharply, and MDI (phenylmethane isocyanate) raw material can be used as a substitute to reduce product prices without affecting performance.
The second is to change the synthesis process route. The production process of waterborne polyurethane is much more complex compared to solvent based products, and the equipment and process requirements are more stringent. Different production processes and routes also result in varying costs for producing water-based resins. Therefore, choosing optimized production processes and routes is also a research focus for water-based polyurethane production enterprises.
The third is to develop high-performance additives. Functional additives are often necessary in the production of waterborne polyurethane. Therefore, resin manufacturers must conduct research and development of additives in order to reduce prices.
The fourth is to quickly establish an industrial chain for the production and application of water-based resins, and reduce the production and procurement costs of raw materials. Strengthen the research and development of raw materials, reduce dependence on imports, and truly achieve low-cost water-based resins.
3. Water based PU resin should have excellent ecological properties
The main factors for the development of water-based PU resin come from its environmental and ecological properties. It is predicted that synthetic leather processed with water-based polyurethane can be used to make massage chairs and grass mattresses. Due to its genuine leather like feel, breathability, and moisture permeability, it is easy to clean, more stain resistant, and has better performance than ordinary bed sheets, making it widely favored by people. Synthetic leather processed with water-based resin can also be used for home interior decoration. Recently, high-end hotels have started using synthetic leather decoration, and with future development, it will inevitably enter ordinary households.
Of course, this requires water-based polyurethane for synthetic leather to have better non-toxic and environmentally friendly properties. Firstly, it is necessary to reduce or eliminate heavy metal elements in water-based polyurethane to prevent excessive heavy metal elements from causing harm to the human body. Secondly, efforts should be made to reduce the amount of solvents used in the synthesis of water-based polyurethane, striving to achieve solvent-free production. Even if solvents are used, they must be chosen to be non-toxic to the human body; In addition, the dosage of additives and colorants should be strictly controlled, and safe and environmentally friendly additives and colorants should be selected. Only by ensuring the ecological integrity of synthetic leather can the application field of synthetic leather be further expanded.
4. Water based PU resin should have better process operability
The annual production of synthetic leather is billions of meters, and the processing of synthetic leather is completely mechanized. Therefore, water-based polyurethane for synthetic leather must have better process operability: firstly, it is convenient to adjust the slurry. Usually, water-based resin must be added with color slurry before it can be used on the machine, so the slurry adjustment must be simple, convenient, easy to implement, and fast. One is to operate the machine well, the water-based resin slurry must meet the requirements of the machine operation, the viscosity is easy to control, and there will be no sagging, clumping or layering during application. Secondly, it is easy to dry. Although the evaporation rate of water is slow and water-based PU resin absorbs a large amount of energy during film formation, it can be technically modified to accelerate the evaporation of resin moisture, thus meeting the requirements of increasing production capacity during peak seasons in tanneries.
Of course, the development of water-based polyurethane in synthetic leather must comply with the development of water-based ecological synthetic leather and meet the needs of the end market. Therefore, the development of the entire water-based ecological synthetic leather industry cannot be achieved overnight. This requires close cooperation, tenacious efforts, and arduous work from polyurethane researchers and leather engineering technicians. I believe that in the near future, environmentally friendly and eco-friendly water-based polyurethane and water-based ecological synthetic leather will become the mainstream of the industry.