Polyester Adhesion Promoters for Urethane Inks
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Solution Overview
Problem
Existing adhesion promoters, such as organo-titanium compounds, often cause undesirable yellowing in ink and coating films and require additional components to stabilize viscosity, which can be impractical or increase VOC levels, necessitating the need for alternative adhesion promoters for printing inks and coatings, especially on plastic substrates.
Innovation Solution
Development of hydroxyl- and carboxy-functional polyester resins with specific molecular weight and glass transition temperature characteristics, formed by reacting dibasic organic acids and polyols, which serve as single-component adhesion promoters compatible with polyurethanes and other polymeric binders, eliminating the need for titanium compounds and maintaining ink stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If organo-titanium adhesion promoters are used, then adhesion between ink and substrate is improved, but yellow color is imparted to the ink
Solution Approach 1:
The patent replaces expensive, problematic organo-titanium compounds with a cheaper, stable polyester adhesion promoter that does not cause yellowing. The polyester resin serves as a disposable alternative that achieves the same adhesion function without the harmful side effects.
Solution Approach 2:
The invention changes the chemical composition parameters by using a polyester resin with specific molecular weight (500-5000), glass transition temperature (-50°C to 50°C), and functional group content (0.1-10 mmol/g) to achieve adhesion promotion without the yellowing effect of titanium compounds.
2Strength
If titanium alkoxides are used as adhesion promoters, then adhesion is improved, but viscosity stability requires additional alcohol components
Solution Approach 1:
The patent extracts and eliminates the need for additional alcohol components by using a polyester adhesion promoter that provides both adhesion promotion and viscosity stability inherently, without requiring separate stabilizing agents.
Solution Approach 2:
The polyester resin performs multiple functions simultaneously: it acts as an adhesion promoter, a viscosity stabilizer, and a compatible component with polyurethane and acrylic binders, eliminating the need for separate functional additives.
3Strength
If organo titanates are used for crosslinking, then adhesion and resistance properties are enhanced, but crosslinking reactions occur in liquid formulation reducing stability
Solution Approach 1:
The patent applies preliminary anti-action by using a polyester resin that prevents unwanted crosslinking reactions before they occur in the liquid formulation, maintaining stability during storage and application while still providing adhesion promotion.
Solution Approach 2:
The invention replaces the reactive organo titanate crosslinkers with a stable polyester adhesion promoter that provides the necessary adhesion function without causing premature crosslinking or formulation instability.
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 novel polyester resins provide effective adhesion improvement without yellowing, maintain low ink viscosities, and enhance storage stability, allowing for higher solid content inks with lower VOC emissions, while being cost-effective and compatible with various polymeric substrates.
Implementation Method 1
hydroxyl- and carboxy-functional polyester resins... formed by reacting dibasic organic acids and polyols
Data Source
AI summary
The present invention concerns polyester resins of General Formula I (HO-[R1R2C(CH2-)]a[- OCOCxHyCO2-]b[-CpHzO-]c-H) or General Formula II (HO-[R1R2C(CH2-)2]a[-OCOCxHyCO2-]b[- CH2CR3(CO2H)CH2O]d-H), wherein R1, R2, a, b, c, d, x, y, p, and z are as defined herein, for use in inks and coating compositions. The polyester resins of the present invention are particularly, but not exclusively, suitable to enhance the adhesion between a printing ink or coating composition and a substrate, especially a plastic substrate, to which it is applied. The polyester adhesion promoters of the invention are compatible with urethane-based inks and coating compositions.