Sheet-like article and method for producing same
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Solution Overview
Problem
Current sheet materials using water-dispersed polyurethane for artificial leather applications face challenges in achieving a balance between soft texture and sufficient light resistance, with existing methods either resulting in hard textures or insufficient wear and light resistance.
Innovation Solution
A sheet material produced using a polymer elastic body with a polyether diol and a monovalent positive ion-including inorganic salt, combined with a carbodiimide-based crosslinker, and subjected to specific thermal treatments to create a three-dimensional crosslinked structure, enhancing both flexibility and light resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If water-dispersed polyurethane is used with conventional wet coagulation method, then light resistance is improved, but texture becomes hard
Solution Approach 1:
The invention changes the coagulation temperature parameter from conventional low temperature to specifically 80°C or higher, which fundamentally alters the coagulation mechanism. At this elevated temperature, water-dispersed polyurethane undergoes a different coagulation pathway that forms a porous film structure similar to organic solvent-based methods, thereby achieving both good light resistance and soft texture simultaneously
Solution Approach 2:
The invention uses a composite approach by combining water-dispersed polyurethane (environmentally friendly) with specific coagulation conditions (80°C or higher) to create a polyurethane film that exhibits properties of both conventional methods: the environmental benefits of water-based dispersion and the soft, porous structure characteristic of organic solvent-based coagulation
2Ease of operation
If organic solvent-based polyurethane is used, then soft texture is achieved, but environmental harm increases
Solution Approach 1:
The invention substitutes the chemical mechanism of organic solvent-based coagulation with a thermal-mechanical process. Instead of using organic solvents to dissolve and then coagulate polyurethane, the invention uses water-dispersed polyurethane and applies thermal energy (80°C or higher) to achieve coagulation, thereby replacing harmful chemical substances with a physical thermal process
Solution Approach 2:
The invention changes the fundamental parameter of coagulation temperature to 80°C or higher, which transforms the coagulation behavior of water-dispersed polyurethane. This parameter change enables the formation of a porous film structure that was previously only achievable with organic solvents, thus achieving the same soft texture effect without environmental harm
3Ease of operation
If water-dispersed polyurethane is used with hot water treatment, then texture softness is improved, but wear resistance deteriorates
Solution Approach 1:
The invention precisely controls the coagulation temperature parameter to be 80°C or higher, which optimizes the coagulation process to simultaneously achieve soft texture and maintain wear resistance. This specific temperature parameter prevents the polyurethane film from becoming too thin or too dense, preserving both texture softness and structural integrity for wear resistance
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 resulting sheet material exhibits a good balance between soft texture and superior light resistance, maintaining flexibility while providing improved wear and heat resistance.
Implementation Method 1
a coagulation temperature of the aqueous dispersion being 80°C or more; a heating treatment at a temperature of 120°C or more and 180°C or less
Implementation Method 2
the polymer elastic body internally has an N-acylurea bond and/or an isourea bond
Data Source
AI summary
The purpose of the present invention is to provide: a sheet-like article which has a good balance between soft texture and excellent light resistance; and a method for producing this sheet-like article. In order to achieve this purpose, a sheet-like article according to the present invention has the following configuration. Specifically, a sheet-like article which contains a polymer elastic body in a fibrous base material, wherein: the fibrous base material is composed of ultrafine fibers that have an average single fiber diameter of from 0.1 µm to 10 µm; the polymer elastic body has a hydrophilic group, while containing a polyether diol as a constituent; the polymer elastic body internally has an N-acylurea bond and/or an isourea bond; and the condition 1 and the condition 2 described below are satisfied. Condition 1: The bending resistance in the lengthwise direction as determined in accordance with specific standards is from 40 mm to 140 mm. Condition 2: The abrasion weight loss after 20,000 cycles of a Martindale abrasion test set forth in JIS L 1096 (2005) after a light resistance test as performed under the conditions defined in accordance with specific standards is 25 mg or less.