Liquid silicone rubber (LSR), as a high-performance elastomeric material, has been increasingly used in the leather industry in recent years. Its unique physical and chemical properties have brought unprecedented functional improvements and design possibilities to leather products. This article will comprehensively discuss the application technology, advantages and characteristics of liquid silicone rubber on leather substrates, as well as future development trends.
Liquid silicone rubber is a two-component thermosetting elastomer based on polysiloxane, with the following outstanding characteristics:
Excellent temperature resistance: The operating temperature range is -50℃ to 250℃, far exceeding the tolerance limit of traditional leather
Excellent elasticity and rebound: The elongation can reach 300-1000%, and the permanent deformation is small
Chemical stability: Resistant to ozone, ultraviolet rays, acids, alkalis and various solvents
Physiological inertness: non-toxic and odorless, in line with food and medical standards
Good processing performance: It can be formed by injection molding, coating and other methods
These characteristics make LSR an ideal material for leather modification and compounding, which can make up for the functional deficiencies of natural leather.
The main application areas of liquid silicone rubber on leather
1. Functional surface coating
Liquid silicone rubber can be used as a high-performance coating on leather surfaces:
Waterproof and breathable coating: The microporous silicone rubber membrane allows a water vapor permeability of up to 5000g/m²·24h, while also having excellent waterproof properties
Anti-fouling and easy-to-clean coating: Low surface energy (about 24mN/m), oily stains are difficult to adhere to
Abrasion-resistant protective layer: It can increase the wear resistance of the leather surface by 3-5 times, especially suitable for high-frequency friction areas such as shoe uppers, bags, etc.
Touch improvement: Provides a variety of touch options from ultra-soft to elastic
2. Composite structural materials
Realize the structural composite of leather and LSR through lamination or co-molding process:
Enhanced edge treatment: Injecting LSR into the edge of leather goods can significantly improve durability
Shock-absorbing midsole: The leather-LSR composite structure used in sports shoes combines beauty and functionality
Flexible electronic integration: Provide conductive silicone rubber embedding solutions for smart wearable leather products
3. Decoration and personalized applications
Three-dimensional decorative effect: micron-level pattern replication through precision molds
Transparent/translucent effect: keep the leather texture visible while providing protection
Color innovation: silicone rubber can load high-concentration color paste without affecting performance
Luminous/temperature-changing function: LSR with integrated special fillers gives leather a dynamic visual effect
Liquid silicone rubber and leather bonding process
One. Surface pretreatment technology
Plasma treatment: Increase the surface energy of leather to more than 40mN/m, enhance the bonding strength
Primer treatment: Special primer can make the peel strength reach 4-6N/mm
Laser microstructuring: Create microscopic mechanical interlocking structure
Two. Main molding process
Transfer molding:
Process temperature: 160-180℃
Molding pressure: 5-15MPa
Curing time: 30-90 seconds
Spray curing:
Film thickness control: 0.1-2mm
Curing conditions: 120℃×10min or room temperature vulcanization
Injection molding:
Melt temperature: 20-40℃
Injection speed: 50-200mm/s
Mold temperature: 170-200℃
Three. Key points of process control
Moisture control: The moisture content of leather needs to be controlled at 8-12%
Temperature management: Avoid local overheating that causes leather carbonization
Stress design: Consider the difference in thermal expansion coefficients of the two materials (leather: 50-100×10⁻⁶/℃; LSR: 250-300×10⁻⁶/℃)
Application Case Analysis
1. High-end car interior
A luxury car uses LSR-leather composite steering wheel:
Abrasion resistance is improved to 500,000 friction tests without visible wear
Sweat resistance passes ISO 105-E04 standard
Touch temperature is 8-10℃ higher than traditional leather in winter
2. Medical protective equipment
Antibacterial LSR-coated leather protective gear:
Antibacterial rate > 99.9% (for MRSA, E.coli)
Can withstand more than 100 disinfectant wipes
Breathability maintains more than 85% of the substrate
3. Outdoor equipment
Application case of mountaineering boots:
Waterproof performance: hydrostatic pressure > 10000mmH₂O
Low-temperature elasticity: no cracks when bent at -40℃
Anti-slip performance: wet friction coefficient > 0.8
Technical challenges and development trends
1. Current technical bottlenecks
Adhesion reliability: interface stability under long-term dynamic use
Thickness control: uniformity of ultra-thin coatings (<100μm)
Cost control: the price of high-performance LSR materials is about 3-5 times that of ordinary PU coatings
2. Future development direction
Intelligent integration:
Embedded flexible sensors
Self-healing coating technology
Dynamic temperature control function
Sustainable development:
Development of bio-based silicone rubber
Closed-loop recycling system
Low-temperature curing process (energy consumption reduced by 30%)
Metamaterial design:
Structured hydrophobic surface
Acoustically modulated leather
Optically programmable materials
Liquid silicone rubber has brought revolutionary innovation opportunities to the leather industry. Through material compounding and process innovation, it has achieved complementary advantages between traditional natural materials and modern high-performance polymers. With the continuous advancement of surface treatment technology and molding technology, the application of LSR in the leather field will develop from the current functional supplement to structural innovation, promoting the leapfrog development of leather products towards high performance, intelligence and sustainability. The industry needs to strengthen the tripartite collaboration among material suppliers, equipment manufacturers and terminal brands to jointly overcome key technical bottlenecks and release the maximum value potential of this material combination.
