Skin Foam-in-Place Foamed Article With Density Gradient Liner

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Solution Overview

Problem

The existing method of producing skin foam-in-place foamed articles using a polyurethane sheet with an open cell structure often results in liquid polyurethane penetrating the sheet, leading to impaired touch feeling and increased costs due to the need for additional sealing, and surface treatments like corona treatment can compromise the foaming process by creating through-holes.

Innovation Solution

A skin foam-in-place foamed article is created using a bag-like outer material with a foamed resin liner layer having a closed cell structure and a density gradient, where the pad-side skin layer has a higher density than the bulk layer, and a corona treatment is applied to enhance bonding strength without compromising the foaming process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a polyurethane sheet with open cell structure is used as the liner layer, then the touch feeling is soft and comfortable, but liquid polyurethane penetrates the sheet causing resin pieces to form inside

Engineering Contradiction:

Improvetouch feelingVSAvoidprevention of liquid penetration

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent applies a skin layer with different properties (higher density, lower porosity) on the inner surface of the liner layer that contacts the liquid polyurethane, while the outer layer maintains the soft open-cell structure for comfort. This local differentiation allows the skin layer to prevent penetration while the bulk layer provides softness.

Inventive Principle:

Principle #3Local quality

2Reliability

If a polyethylene sheet with closed cell structure is used as the liner layer, then liquid polyurethane penetration is prevented, but bonding strength with the pad is insufficient

Engineering Contradiction:

Improveprevention of liquid penetrationVSAvoidbonding strength

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The patent creates a skin layer with higher density and different surface properties on the inner surface that provides both penetration resistance and enhanced bonding capability. The skin layer's unique structure allows it to bond effectively with the pad while the outer layer maintains the closed-cell structure for preventing liquid penetration.

Inventive Principle:

Principle #3Local quality

3Strength

If corona treatment is applied to a foamed sheet to increase bonding strength, then surface bonding is improved, but through-holes are generated in the bulk layer causing gas leakage

Engineering Contradiction:

Improvebonding strengthVSAvoidfoaming condition

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The patent applies corona treatment only to the skin layer on the inner surface that contacts the liquid polyurethane, while the bulk layer maintains its intact closed-cell structure. This localized treatment enhances bonding strength at the interface without creating through-holes that would compromise the foaming process.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent divides the liner layer into distinct functional zones: a skin layer for bonding and penetration resistance, and a bulk layer for structural integrity and liquid containment. This segmentation allows different treatments and properties in different regions without compromising overall performance.

Inventive Principle:

Principle #1Segmentation

4Reliability

If additional sealing with polyurethane film is applied to prevent leakage from stitches, then liquid polyurethane leakage is prevented, but production cost increases

Engineering Contradiction:

Improveprevention of leakageVSAvoidproduction cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent removes the need for additional sealing films by incorporating leakage prevention directly into the liner layer structure. The skin layer and closed-cell bulk layer work together to prevent liquid penetration and leakage, eliminating the separate sealing step and associated costs.

Inventive Principle:

Principle #2Taking out (Extraction)

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

This approach results in a skin foam-in-place foamed body with improved touch feeling, foaming conditions, and bonding strength between the liner layer and the pad, while reducing production costs and preventing gas and liquid leakage.

Implementation Method 1

a corona treatment is applied to the pad-side skin layer

Methodology Applied

Scientific EffectCorona treatment: Corona Discharge

Data Source

PatentUS11633937B2Skin foam-in-place foamed article and production method thereof

Publication Date: 2023.04.25 INOAC CORP

AI summary

There is provided a skin foam-in-place foamed article comprising a pad (15) and a bag-like outer material (20) covering the pad (15). The outer material (20) has a top layer (21) and a liner layer (22) made of a foamed resin. The liner layer (22) has a closed cell structure. A pad-side skin layer (27a) having a density higher than that of a bulk layer (26) is provided on the liner layer (22), on a side of the pad (15). A corona treatment is applied to the pad-side skin layer (27a).