Polyester Binder Resin with Isosorbide and Lactic Acid
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Solution Overview
Problem
Conventional polyester binder resins for coatings face challenges in achieving a balance between coating hardness, contamination resistance, hydrolytic resistance, and processability, while also being eco-friendly due to their fossil-based origins. Additionally, biomass-derived compounds like isosorbide have low reactivity, making it difficult to produce high-viscosity polyesters suitable for industrial applications.
Innovation Solution
A polyester binder resin copolymerized with terephthalic acid, isophthalic acid, and isosorbide, incorporating lactic acid or its derivatives, which enhances the glass transition temperature and molecular weight, resulting in a coating composition with improved hardness, contamination resistance, and processability, while maintaining a high biomass content.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If high-molecular weight polyester resin with linear structure is used as binder, then processability is improved, but coating hardness, contamination resistance and hydrolytic resistance deteriorate
Solution Approach 1:
The patent changes the molecular structure parameters of polyester resin by introducing cyclic structures (cis-1,4-polybutadiene units) and controlling the glass transition temperature to 70°C or higher, thereby improving coating hardness, contamination resistance and hydrolytic resistance while maintaining good processability through optimized molecular weight and structure
Solution Approach 2:
The patent creates a composite resin system by copolymerizing terephthalic acid, isophthalic acid, and cis-1,4-polybutadiene, combining the benefits of aromatic polyesters (hardness, resistance) with the flexibility and processability of polybutadiene structures, achieving a balanced coating formulation
2Ease of operation
If alkylene oxide group adduct of bisphenol-A is used to increase molecular weight, then processability and adhesivity are improved, but UV stability deteriorates due to excessive ether bonds
Solution Approach 1:
The patent removes bisphenol-A and alkylene oxide structures from the resin composition, extracting the problematic ether bonds that cause UV degradation, while retaining processability through alternative molecular weight control methods using conventional polyester structures with optimized glass transition temperature
Solution Approach 2:
The patent converts the potential harm of high molecular weight (which can reduce UV stability) into a benefit by carefully controlling the glass transition temperature and molecular structure, achieving both good processability and UV resistance through optimized polyester backbone structures without problematic side chains
3Ease of operation
If conventional polyester resin is used to achieve good processability, then coating hardness and contamination resistance are insufficient
Solution Approach 1:
The patent changes the glass transition temperature parameter to 70°C or higher through specific structural modifications (cyclic structures, aromatic content control), thereby improving coating hardness and contamination resistance while maintaining processability through optimized molecular weight and structure
4Strength
If tri-functional raw material is used to increase resin hardness, then coating hardness is improved, but processability sharply decreases
Solution Approach 1:
The patent introduces local cyclic structures (1,4-addition products of butadiene) at specific positions in the polymer chain rather than using tri-functional crosslinking agents throughout, achieving localized hardness enhancement while maintaining overall linear chain flexibility and processability
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 resulting coating composition exhibits superior hardness, contamination resistance, hydrolytic resistance, and processability, making it suitable for industrial applications such as can inner sides, household appliances, and construction exterior materials, while being eco-friendly due to its high biomass content.
Implementation Method 1
A polyester binder resin copolymerized with a diacid component comprising 70 to 100 moles % of terephthalic acid and/or isophthalic acid with respect to the total amount of the diacid component, a diol component comprising 10 to 55 moles% of isosorbide, with respect to a total diol component, and 1 to 50% by weight of lactic acid or a compound derived therefrom
Data Source
AI summary
Disclosed are a polyester binder resin for coating which is copolymerized with lactic acid or a compound derived therefrom and isosorbide, and thus has a high content of biomass-derived compounds, and exhibits superior coating hardness, contamination resistance, hydrolytic resistance, processability and the like, and a coating composition comprising the same. The polyester resin binder for coating is copolymerized with a diacid component, a diol component comprising 1 to 60 moles of isosorbide, with respect to a total diol component, and 1 to 50% by weight of lactic acid or a compound derived therefrom, with respect to the total amount of resin polymerization reactants, wherein the polyester resin binder for coating has a structure in which a diacid moiety derived from the diacid component, a diol moiety derived from the diol component, and a hydroxyl monoacid moiety derived from the lactic acid or a compound derived therefrom are repeated.