Grained leather-like sheet
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Solution Overview
Problem
Grain-finished leather-like sheets colored in red-based colors often experience cracking due to the use of quinacridone-based red pigments, particularly when combined with polyether-based polyurethanes, under UV exposure and flexing endurance tests.
Innovation Solution
A grain-finished leather-like sheet with a polyurethane skin film containing a polyether-based polyurethane, quinacridone-based red pigment, and a hindered amine-based light stabilizer, colored in a bluish red hue (L* ≤80, a* ≥20, b* ≤15), which enhances flexing endurance and resistance to cracking, with a flexing endurance test cycle exceeding 100,000 cycles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If quinacridone-based red pigment is used to color the polyurethane skin film, then red-based coloration is achieved, but cracking occurs over time under UV exposure and flexing
Solution Approach 1:
A hindered amine-based light stabilizer is introduced as an intermediary substance between the quinacridone-based red pigment and the polyurethane skin film. This stabilizer acts as a mediator that protects the pigment-polymer interface from UV-induced degradation, preventing cracking while maintaining the red-based coloration. The stabilizer absorbs UV energy and prevents it from reaching the vulnerable pigment-polymer boundary layer.
Solution Approach 2:
The invention changes the chemical composition parameters of the polyurethane skin film by incorporating a hindered amine-based light stabilizer. This parameter change modifies the material's UV resistance properties without affecting the coloration achieved by the quinacridone-based red pigment. The stabilizer concentration is optimized to provide adequate protection while maintaining the desired color properties.
2Stability of the object's composition
If polyether-based polyurethane is combined with quinacridone-based red pigment, then color stability is improved, but cracking resistance deteriorates under flexing endurance test
Solution Approach 1:
The hindered amine-based light stabilizer serves as an intermediary that decouples the relationship between the polyether-based polyurethane and the quinacridone-based red pigment. It protects the polymer-pigment interface from UV degradation, preventing the formation of cracks that would otherwise occur during flexing endurance tests. This allows the combination of polyether-based polyurethane and quinacridone-based red pigment to be used together without suffering from cracking issues.
3Adaptability or versatility
If the polyurethane skin film is colored in red-based colors using various pigments, then color variety is achieved, but cracking occurs under prolonged UV exposure
Solution Approach 1:
The hindered amine-based light stabilizer acts as a universal intermediary that protects against UV-induced cracking regardless of which red-based pigment is used. It provides a general protective mechanism at the polymer-pigment interface that works with various pigment types, allowing color variety to be maintained while preventing UV-related damage.
Solution Approach 2:
The invention converts the potentially harmful interaction between UV light and the pigment-polymer interface into a beneficial protective mechanism. The hindered amine-based light stabilizer absorbs the harmful UV energy and converts it into harmless forms, protecting the underlying polymer and pigment structures from degradation. This transforms the UV exposure from a harmful factor into an opportunity for the stabilizer to demonstrate its protective function.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution significantly reduces the occurrence of cracking in the polyurethane skin film, maintaining durability and color stability under prolonged UV exposure and flexing, making it suitable for applications requiring resistance to light and mechanical stress.
Implementation Method 1
the polyurethane skin film contains a hindered amine-based light stabilizer... after the grain-finished leather-like sheet has been irradiated with carbon arc... using ultraviolet carbon arc lamp light
Implementation Method 2
cracking may occur over time in a polyurethane skin film... when the polyurethane skin film is irradiated with carbon arc... the occurrence rate of cracking is significantly high
Data Source
AI summary
Disclosed is a grain-finished leather-like sheet including a polyurethane skin film containing a polyether-based polyurethane, wherein the polyurethane skin film contains a quinacridone-based red pigment, and is colored in a red color having an L* value of ≤80, an a* value of ≥20, and a b* value of ≤15 in an L*a*b* color system, and the number of cycles of a flexing endurance test at which cracking occurs in a surface of the polyurethane skin film is 100000 or more, when the flexing endurance test is performed on the grain-finished leather-like sheet under an environment of 20° C. using a flexometer after the grain-finished leather-like sheet has been irradiated with carbon arc at a black panel temperature of 63° C. for 100 hours with an irradiance of 500±50 W/m2, using ultraviolet carbon arc lamp light compliant with JIS B 7751.