Metallic Decorative Sheet Edge Detachment Prevention

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Solution Overview

Problem

Conventional metallic decorative sheets used in home electric appliances face issues with the metal thin-film layer being exposed at the edge regions, leading to detachment when contacted with alkaline solutions, which affects the visual appearance and durability of the product.

Innovation Solution

A production method involving a metallic decorative sheet where a metal thin-film layer is formed on the back surface of a transparent thermoplastic resin film, with specific regions removed to prevent exposure and an ink layer applied to cover the metal thin-film layer and edge regions, ensuring the metal layer is not visible and secure during the insert molding process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If the metal thin-film layer is vapor deposited on the entire back surface of the transparent thermoplastic resin film, then the metallic decorative effect is enhanced, but the metal thin-film layer becomes exposed at the edge region and detaches when contacted with alkaline solutions

Engineering Contradiction:

Improvemetallic decorative effectVSAvoidedge region detachment resistance

Core Design Contradiction:

Illumination intensityVSReliability

Solution Approach 1:

The patent applies different treatments to different regions of the metal thin-film layer. The edge region (second region) is removed to prevent detachment, while the central region (first region) is retained to provide metallic decorative effect. This local differentiation resolves the contradiction by sacrificing the metallic effect at the edge (where it causes harm) while preserving it in the central area (where it provides benefit).

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The back surface of the transparent thermoplastic resin film is divided into two distinct regions: a first region (central area) where the metal thin-film layer is retained for decorative purposes, and a second region (edge area) where the metal thin-film layer is removed to prevent detachment. This segmentation allows each region to serve its specific function without compromising the other.

Inventive Principle:

Principle #1Segmentation

2Reliability

If the metal thin-film layer is removed from the edge region to prevent detachment, then the reliability is improved, but the metallic decorative effect is reduced

Engineering Contradiction:

Improveedge region detachment resistanceVSAvoidmetallic decorative effect

Core Design Contradiction:

ReliabilityVSIllumination intensity

Solution Approach 1:

The patent maintains the metal thin-film layer in the central first region to preserve the metallic decorative effect, while selectively removing it only from the edge second region. This localized approach ensures that the decorative effect is maintained where it is most visible and valued, while eliminating the detachment problem only at the edges where it occurs.

Inventive Principle:

Principle #3Local quality

3Object-affected harmful factors

If the ink layer is applied to cover the entire back surface including the metal thin-film layer, then the metal thin-film layer is not visible, but the production process becomes more complex

Engineering Contradiction:

Improvemetal thin-film layer visibilityVSAvoidproduction process complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent performs the metal thin-film layer removal at the edge region before applying the ink layer. This preliminary action ensures that the ink layer only needs to cover the central first region where the metal thin-film layer remains, rather than the entire back surface. This reduces the complexity of the ink layer application process while still achieving the goal of preventing metal thin-film layer visibility in problematic areas.

Inventive Principle:

Principle #10Preliminary action

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 method effectively prevents the metal thin-film layer from being seen and detached at the edge regions, maintaining the visual appearance and durability of the product without increasing production steps, as demonstrated by resistance to alkaline solutions like chlorine bleach.

Implementation Method 1

vapor depositing thereon a metal thin-film layer 112

Methodology Applied

Scientific EffectVapor deposition: Physical Vapour Deposition

Implementation Method 2

an ink layer 114 to preventing the metal thin-film layer from being seen

Methodology Applied

Scientific EffectAbsorption: Absorption (physical)

Implementation Method 3

a binder layer 115 for binding with a thermoplastic resin molded body 120

Methodology Applied

Scientific EffectAdhesion: Adhesive

Data Source

PatentUS8728577B2Metallic decorative sheet, production method of metallic decorative sheet, and production method of insert molded body using metallic decorative sheet

Publication Date: 2014.05.20 SANWA SCREEN CO LTD

AI summary

Provided is a production method of a metallic decorative sheet capable of preventing from getting detached at edge portions. The production method of a metallic decorative sheet for insert molding comprises steps of forming a metal thin-film layer 12 on a back surface of a transparent thermoplastic resin film 11; removing a first region J for displaying a non-metallic design on an outer surface of the thermoplastic resin film 11 and a second region K which is at least a part of edge region of the thermoplastic resin film 11 from the metal thin-film layer 12; and laminating an ink layer 14 on at least the metal thin-film layer 12 and the second region K.