Method for producing a pigmented polymer material
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Solution Overview
Problem
Polypropylene films and sheets face challenges with ink adhesion, poor dye substantivity, and high risk of ink transfer due to their hydrophobic nature, leading to inferior print quality and vulnerability to mechanical damage without protective coatings.
Innovation Solution
A method involving a polymer material blend with a binding agent, where the material is heated to an activation temperature and contacted with an aqueous pigment composition, followed by a fixation step to enhance pigment affinity and stability, allowing for improved color intensity and resistance to wear without requiring surface activation or protective coatings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polypropylene films are used as packaging material, then good chemical resistance and durability are achieved, but ink adhesion is poor and dye substantivity is low due to hydrophobicity
Solution Approach 1:
The patent applies preliminary corona treatment to the polypropylene film surface before printing to create polar groups that improve ink adhesion. This preliminary surface modification allows the hydrophobic polypropylene to accept aqueous inks and dyes without requiring chemical composition changes, thus maintaining chemical resistance while improving printability
Solution Approach 2:
The patent changes the surface energy parameters of polypropylene through corona discharge treatment, transforming the hydrophobic surface into a more hydrophilic state. This parameter change enables better wetting and adhesion of aqueous pigment compositions without altering the bulk chemical properties of the polymer
2Strength
If protective transparent coating is applied on top of printed image, then resistance to mechanical damage is improved, but additional process step is required and print quality may be adversely affected
Solution Approach 1:
The patent incorporates binding agents and adhesion promoters into the polypropylene film during the extrusion process, before printing. This preliminary incorporation creates a print-receptive surface layer that provides both ink adhesion and mechanical protection, eliminating the need for subsequent protective coating applications
Solution Approach 2:
The patent merges the functions of structural integrity, ink adhesion, and mechanical protection into a single integrated film structure. The binding agents are distributed throughout the film thickness, providing both print reception and protective functions simultaneously, thus combining multiple functions into one component
3Ease of manufacture
If polypropylene material is contacted with aqueous ink, then printing process is simplified, but ink transfer problems occur and color intensity is poor
Solution Approach 1:
The patent introduces binding agents as intermediary substances between the aqueous ink and polypropylene surface. These binding agents act as mediators that facilitate the transfer and fixation of pigment particles onto the polypropylene, enabling good color intensity and print quality while maintaining the simplicity of aqueous ink application
Solution Approach 2:
The patent replaces the need for mechanical surface activation (such as flame treatment or plasma) with chemical modification through corona discharge and binding agent incorporation. This substitution maintains process simplicity while achieving better ink adhesion and color intensity through chemical affinity rather than mechanical surface roughening
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 results in a polymer material with enhanced pigment affinity, improved color stability, and resistance to mechanical damage, maintaining print quality without additional coatings, suitable for use in packaging and other applications.
Implementation Method 1
heating the polymer material to an activation temperature below the softening temperature of the polymer material
Implementation Method 2
contacting the polymer material with the aqueous pigment composition for a period of time sufficient to form a pigmented polymer material
Implementation Method 3
subjecting the pigmented polymer material to a fixation step to fixate the at least one pigment therein by cooling the pigmented polymer material to a fixation temperature
Data Source
AI summary
Provided is a method for dyeing a polymer material with an aqueous pigment composition containing at least one pigment dispersed therein, wherein the polymer material is a blend including a first polymer composition and a second polymer composition which is compatible with the first polymer composition, which second polymer composition includes a binding agent for the at least one pigment. The method includes the steps of heating the polymer material to an activation temperature below the softening temperature of the polymer material, contacting the polymer material with the aqueous pigment composition at a contact temperature for a period of time sufficient to form a pigmented polymer material, subjecting the pigmented polymer material to a fixation step to fixate the at least one pigment therein by cooling the pigmented polymer material to a fixation temperature which is lower than the temperature at which contacting of the polymer material with the aqueous pigment composition is carried out.