Thermal Transfer Ink with Fixing Layer for Plastic Decoration

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Solution Overview

Problem

Existing methods for decorating polyolefin plastic articles are inefficient, as they often result in unstable thermal transfers due to high temperatures, ink splitting, and flash from adjoining sections, making it difficult to achieve reliable and cost-effective decoration, especially with high-speed equipment.

Innovation Solution

The development of new inks and thermal transfers with a fixing layer on a carrier film or paper, allowing for lower temperature curing and compatibility with polyethylene and polypropylene plastics, enabling the use of heat-sensitive carrier films and embossed stamping dies for stable and integral decoration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If high temperature thermal transfer is used to decorate polyolefin plastic articles, then the ink can be fused onto the plastic surface, but the carrier film experiences unacceptable shrinkage and the ink becomes unstable and difficult to manufacture

Engineering Contradiction:
Improvestability of thermal transferVSAvoidcuring temperature
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The patent divides the transfer system into separate functional layers: a carrier film, a printed ink layer containing polyolefin particles, and a distinct polyolefin layer. This segmentation allows each layer to perform its specific function at appropriate temperatures, with the ink layer fusing to the plastic article without requiring the entire carrier film to withstand high temperatures, thus preventing shrinkage and instability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a release layer as an intermediary between the printed ink layer and the carrier film. This release layer enables the ink to be transferred from the carrier film to the plastic article during heating, while the carrier film itself does not need to be exposed to high temperatures, thereby avoiding shrinkage and maintaining stability.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If high temperature fusion is used to transfer ink onto plastic articles, then the ink bonds to the surface, but the ink splits raggedly at die edges making tipping embossed sections difficult

Engineering Contradiction:
Improveadhesion of ink to plasticVSAvoidedge definition of transferred ink
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent changes the physical state and composition parameters of the ink layer by incorporating polyolefin particles and using a vehicle that allows controlled fusion. This enables the ink to bond reliably to the plastic surface while maintaining edge definition, as the ink layer can be formulated to fuse uniformly without ragged splitting at die edges.

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If thermal transfer is used to decorate plastic articles, then decoration is achieved, but flash from adjoining sections of ink occurs

Engineering Contradiction:
Improvedecoration processVSAvoidcleanliness of transferred image
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent extracts the ink layer from the carrier film during the transfer process. The release layer facilitates the separation of the ink layer from the carrier film, allowing the ink to be transferred cleanly to the plastic article without carrying over flash or unwanted material from adjoining sections, thus producing a clean transferred image.

Inventive Principle:
Principle #2Taking out (Extraction)

4Reliability

If oxidation is performed on plastic surface prior to coating, then adhesion of decorative coating is improved, but processing time and manufacturing cost increase

Engineering Contradiction:
Improveadhesion of coating to plasticVSAvoidprocessing time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent uses homogeneity of material composition by formulating the ink layer with polyolefin particles that are chemically compatible with polyolefin plastic articles. This material matching eliminates the need for oxidation or surface treatment, as the ink layer can adhere directly to the plastic surface through material compatibility, thereby reducing processing time and cost.

Inventive Principle:
Principle #33Homogeneity

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 solution provides a stable and cost-effective method for decorating plastic articles by preventing ink co-mingling with the fixing layer, reducing shrinkage, and allowing for the use of lower temperatures, resulting in a permanently fused and clean decoration without flash or delamination.

Implementation Method 1

use of lower temperature curing of the ink layer to prevent a co-mingling of the printed ink layer polyolefin or other plastic particles and the fixing layer

Methodology Applied
Scientific EffectThermal curing: Heating

Implementation Method 2

a thermal transfer is provided having an indicia layer which can be fused into the surface of a molded plastic article using various heat transfer processes

Methodology Applied
Scientific EffectThermal fusion: Heating

Data Source

PatentUS12070965B2Ink, transfers, methods of making transfers, and methods of using transfers to decorate plastic articles
Publication Date: 2024.08.27 THE MICHAEL & KATHLEEN STEVENSON FAMILY LLP

AI summary

A thermal indicia transfer comprises a fixing layer between a carrier sheet and a printed ink layer. The ink comprises plastic particles, a solvent, an indicia additive, a dispersing agent, and optionally a binder. The fixing layer is coated onto the carrier sheet and cured. The ink layer is printed onto the fixing layer where the plastic particles are held in place by the tackiness and structure of the fixing layer. The printed ink layer is dried at a temperature high enough to remove the solvent from the ink layer, but low enough to prevent melting of the plastic particles.