What are the main ingredients of film-forming agents? How to choose?

Main ingredients of film-forming agents and their selection methods

Film-forming agent is a chemical widely used in leather processing. It is mainly used for surface treatment of leather to improve its appearance, feel, wear resistance, water resistance and other properties. The composition and selection of film-forming agent have an important impact on the quality of leather. This article will introduce the main components of film-forming agent and its selection method in detail.

1. Main ingredients of film-forming agents

1. Film-forming substances

   Film-forming substances are the core components of film-forming agents, responsible for forming a uniform film on the leather surface. Common film-forming substances include:

   - Acrylic resin: has good film-forming properties and flexibility, and is widely used in leather finishing.

   - Polyurethane resin: has excellent wear resistance and elasticity, suitable for high-end leather products.

   - Nitrocellulose: It has a fast film-forming speed but poor weather resistance and is often used for low-grade leather.

2. Plasticizer

   Plasticizers are used to improve the flexibility and ductility of film-forming materials and prevent cracking of the film layer. Common plasticizers include:

   - Phthalate esters: such as dibutyl phthalate (DBP), which has a good plasticizing effect.

   - Citrate Esters: Environmentally friendly plasticizers, suitable for products with high environmental requirements.

3. Solvent

   Solvents are used to dissolve film-forming substances and plasticizers so that they can be evenly coated on the leather surface. Common solvents include:

   - Water: Environmentally friendly solvent, suitable for water-based film agents.

   - Organic solvents: such as acetone, ethyl acetate, etc., suitable for solvent-based film agents.

4. Additives

   Additives are used to improve the performance of film agents, such as leveling agents, defoamers, mildew inhibitors, etc. Common additives include:

   - Leveling agent: improves the flatness of the coating and prevents orange peel phenomenon.

   - Defoamer: prevents bubbles from forming during coating.

   - Anti-mold agent: prevents leather from getting moldy during storage and use.

5. Pigments and dyes

   Pigments and dyes are used to give leather color and decorative effects. Common pigments are:

   - Inorganic pigments: such as titanium dioxide, iron oxide, etc., have good hiding power and weather resistance.

   - Organic pigments: bright colors, but poor weather resistance.

2. Selection method of film agent

1. Choose by leather type

   Different types of leather have different requirements for coating agents. For example:

   - Cowhide: Usually requires a coating agent with good wear resistance and elasticity, such as polyurethane resin.

   - Sheepskin: requires a coating agent with better softness and breathability, such as acrylic resin.

   - Pigskin: requires a coating agent with better covering power, such as nitrocellulose.

2. Choose according to purpose

   The requirements for coating agents vary depending on the purpose of leather products. For example:

   - Upper leather: requires a film agent with better abrasion resistance and water resistance.

   - Garment leather: requires a film agent with good softness and breathability.

   - Furniture leather: requires a film agent with good scratch resistance and stain resistance.

3. Choose according to environmental protection requirements

   With the improvement of environmental awareness, it is becoming more and more important to choose environmentally friendly coating agents. For example:

   - Water-based film-forming agent: uses water as solvent, has good environmental performance, but has a slow film-forming speed.

   - Solvent-based film-forming agent: It forms film quickly, but contains volatile organic compounds (VOCs), which have a certain impact on the environment.

4. Choose based on cost

   The cost of the coating agent is also a factor to consider when choosing. High-end leather products usually choose coating agents with excellent performance but higher costs, such as polyurethane resin; while low-end leather products choose coating agents with lower costs, such as nitrocellulose.

5. Choose according to production process

   Different production processes have different requirements for film-forming agents. For example:

   - Spraying process: A film agent with lower viscosity is required to facilitate uniform spraying.

   - Roller coating process: requires a film coating agent with higher viscosity for easy and uniform coating.

6. Choose according to customer needs

   The specific requirements of customers for leather products are also an important basis for selecting coating agents. For example, if customers require leather to have a specific color, feel or function (such as waterproof, anti-fouling, etc.), you need to choose the corresponding coating agent.

Conclusion

The main components of film-forming agents include film-forming substances, plasticizers, solvents, additives and pigments/dyes. Choosing a suitable film-forming agent requires comprehensive consideration of factors such as leather type, application, environmental protection requirements, cost, production process and customer needs. By rationally selecting a film-forming agent, the quality and market competitiveness of leather products can be effectively improved.