Structured Transfer Foil for Localized Soft-Touch Molding

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Solution Overview

Problem

Existing methods for creating composite molded parts with soft-touch coatings are labor-intensive, costly, and limited in design flexibility, with full-surface applications leading to high material consumption and susceptibility to scratches, while not allowing for partial soft-touch layers or decorations.

Innovation Solution

A transfer film with a structured topcoat that mimics a soft-touch effect through a master structure, allowing for localized tactile and optical properties, and can be integrated into an IMD process to create decorated injection-molded articles with customizable designs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a full-surface soft-touch coating is applied subsequently to the plastic component, then the tactile soft-touch effect is achieved, but the work steps increase and manual labor is required

Engineering Contradiction:

Improveease of manufactureVSAvoidnumber of work steps

Core Design Contradiction:

Ease of manufactureVSDevice complexity

Solution Approach 1:

The soft-touch effect is created in advance on the transfer foil during manufacturing, before the foil is applied to the plastic component. The master structure with its tactile properties is formed on the carrier film in advance, eliminating the need for subsequent coating steps on the component.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The tactile soft-touch effect is copied onto the transfer foil through the master structure, which replicates the desired surface texture and haptic properties. This copied structure is then transferred to the plastic component during the molding process, avoiding direct application to the component.

Inventive Principle:

Principle #26Copying

2Ease of manufacture

If a full-surface soft-touch coating is applied, then the tactile effect is achieved, but the scrap rate increases

Engineering Contradiction:

Improveease of manufactureVSAvoidscrap rate

Core Design Contradiction:

Ease of manufactureVSLoss of substance

Solution Approach 1:

The soft-touch effect is applied locally to specific areas of the plastic component where it is needed, rather than covering the entire surface. This allows selective application to decorative or functional zones, reducing material consumption and scrap rates.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

Instead of applying the soft-touch coating to the entire surface, the invention uses partial application through the transfer foil, applying the tactile effect only to the areas where the master structure is present, thereby reducing material usage.

Inventive Principle:

Principle #16Partial or excessive action

3Ease of manufacture

If a thick layer is used to achieve the soft-touch effect, then the tactile properties are improved, but the material consumption and costs increase

Engineering Contradiction:

Improveease of manufactureVSAvoidmaterial consumption

Core Design Contradiction:

Ease of manufactureVSQuantity of substance

Solution Approach 1:

The soft-touch effect is achieved through localized structuring on the transfer foil rather than applying a thick layer across the entire surface. The master structure creates the tactile effect in concentrated areas, reducing overall material consumption.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The transfer foil combines a carrier film with a master structure and soft-touch coating in a composite structure. This allows the tactile properties to be achieved through the interaction of different materials and structures, reducing the quantity of soft-touch material needed.

Inventive Principle:

Principle #40Composite materials

4Ease of manufacture

If particles are applied to create the soft-touch effect, then the friction and tactile feel are improved, but the surface becomes sensitive to scratches

Engineering Contradiction:

Improveease of manufactureVSAvoidscratch sensitivity

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The tactile effect is created through localized structuring on the transfer foil rather than applying particles across the entire surface. This concentrated approach reduces the total particle count and minimizes surface sensitivity to scratches.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The invention replaces the mechanical particle-based soft-touch effect with a master structure that creates tactile properties through its geometric configuration. This structural approach eliminates the need for particles that cause scratch sensitivity.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

5Ease of manufacture

If a full-surface application is used, then the soft-touch effect is achieved, but the ability to create decorations or motifs is lost

Engineering Contradiction:

Improveease of manufactureVSAvoiddesign flexibility

Core Design Contradiction:

Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The master structure on the transfer foil can be designed with specific patterns, motifs, or decorative elements in particular areas. This allows the soft-touch effect to be combined with decorative designs, as the structuring is applied locally rather than uniformly across the entire surface.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The transfer foil design can be segmented into different areas with different properties - some areas with the soft-touch master structure and others with different decorations or motifs. This segmentation enables multiple functions and designs to coexist on a single component.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentEP3573841B1Transfer foil, use thereof, a method for producing a transfer foil, and a method for producing an injection-moulded article decorated using a transfer layer of a transfer foil

Publication Date: 2025.10.01 LEONHARD KURZ STIFTUNG & CO KG

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AI summary

The invention relates to a transfer foil (10), in particular a hot-stamping foil, which comprises a carrier foil (12) and, provided on the carrier foil (12) and removable from the carrier foil (12), a transfer layer (14) which has a topcoat (16), wherein a master structure is moulded on the carrier foil (12) on its side facing the transfer layer (14), and wherein the topcoat (16) comprises a patterning with a structure that complements the master structure.