Door body
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Solution Overview
Problem
Conventional door bodies using glass for front panels face issues such as low impact resistance, fragility, and difficulties in handling and processing, while laminated resin sheets used as alternatives suffer from peeling problems under moisture and heat, knocking flaws, and peeling during the foam insulation filling step due to inadequate adhesion strength.
Innovation Solution
A door body design featuring a hard coat laminated sheet with a first hard coat containing no inorganic particles and a second hard coat with inorganic particles, combined with a transparent resin sheet and a pressure-sensitive adhesive layer, ensuring high transparency, abrasion resistance, and improved adhesion to prevent peeling and knocking flaws.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a conventional pressure-sensitive adhesive is used to bond the decorative sheet to the transparent resin sheet, then the bonding process is simple and efficient, but peeling occurs under moisture and heat conditions
Solution Approach 1:
The patent modifies the chemical composition parameters of the pressure-sensitive adhesive by incorporating specific functional groups (carboxyl groups, hydroxyl groups, epoxy groups, isocyanate groups) and controlling molecular weight ranges. These parameter changes enable the adhesive to maintain strong bonding under moisture and heat conditions while preserving production efficiency.
Solution Approach 2:
The patent creates a composite adhesive system by combining multiple functional components: polyol compounds with specific functional groups, polyester polymers with controlled molecular weight, and optional crosslinking agents. This composite material approach achieves both high reliability under environmental stress and practical manufacturability.
2Ease of manufacture
If a conventional pressure-sensitive adhesive is used for bonding, then the process is straightforward, but knocking flaws occur when the decorative sheet is impacted from the back side
Solution Approach 1:
The patent adjusts the molecular weight parameters (50,000-500,000 for polyester polymer) and functional group content to optimize the adhesive's toughness and flexibility. These parameter modifications allow the adhesive layer to absorb impact energy from knocking without transmitting visible flaws to the front surface, while maintaining ease of application.
3Productivity
If a conventional pressure-sensitive adhesive is used, then initial bonding is achieved, but peeling occurs during the foam insulation material filling step
Solution Approach 1:
The patent incorporates functional groups with high thermal stability (isocyanate groups, epoxy groups) and controls the molecular weight of polyester polymer within 50,000-500,000. These parameter changes enable the adhesive to withstand the thermal stress and mechanical pressure of the foam filling process without peeling, while maintaining efficient bonding speed.
Solution Approach 2:
The patent uses the pressure-sensitive adhesive as an intermediary layer between the decorative sheet and transparent resin sheet that specifically counters the peeling forces generated during foam expansion and cooling. The adhesive's compositional parameters are optimized to resist both thermal stress and mechanical separation forces during this critical process.
4Illumination intensity
If glass is used for the front panel, then high transparency and design sense are achieved, but impact resistance is low and the material is fragile
Solution Approach 1:
The patent replaces glass with a composite structure consisting of transparent resin sheet bonded to decorative sheet using specially formulated pressure-sensitive adhesive. This composite material combination maintains the transparency and aesthetic qualities of glass while providing superior impact resistance and flexibility, eliminating the fragility issue.
5Illumination intensity
If glass is used for the front panel, then a sense of design with transparency is achieved, but the specific gravity is high resulting in heavy weight
Solution Approach 1:
The patent substitutes the high-specific-gravity glass material with a composite structure of transparent resin sheet and decorative sheet bonded with lightweight adhesive. This material replacement maintains the desired transparency and design aesthetics while significantly reducing the weight of the door body.
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 provides a door body with enhanced abrasion resistance and improved adhesion, effectively addressing peeling issues under moisture and heat, knocking flaws, and peeling during the foam insulation filling step, while maintaining transparency and design aesthetics.
Implementation Method 1
a pressure-sensitive adhesive can be used advantageously from a viewpoint of preventing thermal discoloration of a printed pattern applied to the decorative sheet and thermal deformation of a wrinkled pattern
Implementation Method 2
A door body capable of maintaining initial characteristics even when being repeatedly wiped with a cloth or the like is required
Implementation Method 3
the foam insulation material is foamed and filled under heating while closely adhering or bonding to a back of a decorative sheet
Implementation Method 4
the foam insulation material is foamed and filled under heating while closely adhering or bonding to a back of a decorative sheet, and subsequently heat shrinkage occurs when cooling is performed
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
One embodiment of the present invention is a door body which opens and closes a front part of an article body, and which has a front panel that constitutes the front of the door body, a frame that supports at least a part of the outside edge of the front panel, and a back panel that constitutes the back of the door body; the front panel includes a hard coat laminated sheet; the hard coat laminated sheet has a first hard coat, a second hard coat and a transparent resin sheet layer in that order from the surface on the front side; the first hard coat is formed from a coating material which contains (A) 100 parts by mass of a polyfunctional(meth)acrylate, (B) 0.01-7 parts by mass of a water repellant and (C) 0.01-10 parts by mass of a silane coupling agent and which does not contain inorganic particles; and the second hard coat is formed from a coating material which contains (A) 100 parts by mass of the polyfunctional (meth)acrylate and (D) 50-300 parts by mass of inorganic fine particles having an average particle diameter of 1-300 nm. This door body may have a display on at least a part of the front thereof.