IMD Layer Encapsulation via Two-Shot Injection Molding

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Solution Overview

Problem

Injection molded products with graphical or colored layers are prone to rapid deterioration due to lack of protection from external environments, especially in harsh conditions, as the edges of applied coatings are not completely sealed, allowing intrusion of contaminants.

Innovation Solution

A two-shot injection molding process creates a three-layer construction with a graphical or color layer sandwiched between a substrate and an overmold, where the overmold completely encapsulates the graphical layer, forming a unitary polymer barrier that is impervious to air and gases, using materials that bond seamlessly at a molecular level.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a single-layer IMD process is used to apply graphical or colored layers to molded structures, then the manufacturing process is simple and cost-effective, but the graphical layer is not adequately protected from environmental degradation and deteriorates rapidly

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidgraphical layer durability

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The single-layer IMD process is segmented into a multi-layer construction with a substrate layer, graphical layer, and protective overmold layer. This segmentation allows each layer to serve its specific function while collectively providing enhanced durability and protection against environmental degradation.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention uses composite material construction combining different polymer layers (substrate and overmold) with the graphical layer in between. This composite structure provides both the aesthetic graphical elements and the protective barrier needed to resist environmental factors like UV radiation, oxidation, and chemical exposure.

Inventive Principle:

Principle #40Composite materials

2Object-affected harmful factors

If a protective coating is applied to the outside of the part, then some protection is provided, but the edges where individual coatings meet are not completely sealed, allowing intrusion of damaging substances

Engineering Contradiction:

Improveprotection from environmental factorsVSAvoidcoating structure complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The substrate layer and overmold layer are merged into a unitary bonded structure through the IMD process, creating seamless edges that completely seal the graphical layer. This eliminates the gaps and seams that occur when separate coatings are applied, preventing contaminant intrusion at edge interfaces.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The overmold layer acts as a flexible protective shell that completely encapsulates the graphical layer. This thin film approach provides comprehensive protection while maintaining the ability to conform to complex part geometries and seal edges effectively.

Inventive Principle:

Principle #30Flexible shells and thin films

3Adaptability or versatility

If the graphical layer is exposed to harsh environments such as chemically treated underwater environments or extreme temperatures, then the product can be used in diverse applications, but the graphical layer deteriorates rapidly due to lack of sufficient protection

Engineering Contradiction:

Improveapplication rangeVSAvoidgraphical layer lifespan

Core Design Contradiction:

Adaptability or versatilityVSDuration of action of stationary object

Solution Approach 1:

The overmold layer is applied beforehand to cushion and protect the graphical layer from harsh environmental conditions before exposure occurs. This protective barrier prevents direct contact between the graphical layer and damaging factors such as chemicals, UV radiation, and extreme temperatures, thereby extending lifespan while maintaining versatility.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

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 hermetically sealed graphical layer, protecting it from environmental degradation and ensuring durability in harsh conditions by eliminating seams and preventing contaminant intrusion, thus extending the lifespan of the product.

Implementation Method 1

using materials that bond seamlessly at a molecular level

Methodology Applied

Scientific EffectMolecular bonding: Chemical Bonding

Implementation Method 2

forming a unitary polymer barrier that is impervious to air and gases

Methodology Applied

Scientific EffectPhysical containment: Physical Containment

Data Source

PatentUS11691321B2Polymer sealed in-mold decoration and method of manufacture

Publication Date: 2023.07.04 CURNUTT PROD LLC

AI summary

An injection molded product formed from an inner layer, or substrate, to which an aesthetic IMD layer is bonded during a first injection molding process, leaving a portion of the substrate exposed about the perimeter(s) of the substrate. A transparent outer layer, or overmold, is then injection molded over the top of the IMD layer and substrate, bonding substantially to the IMD layer and to the substrate where it remains exposed following the first injection molding. The process of forming a product through the disclosed two-step injection molding process creates a customizable, aesthetic product with an aesthetic IMD layer completely encapsulated between the substrate and a clear overmold in such a way to protect the IMD layer from the environment in which the product is used.