Polyester Polyol Clarity via Clarifier Mediator
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Solution Overview
Problem
The challenge lies in producing polyester polyols from recycled thermoplastics that maintain clarity over extended periods, particularly those with high aromatic ring content, such as recycled PET, PBT, and PTT, as existing methods often result in opaque products due to hydrophobe modification, which is undesirable for polyurethane formulations.
Innovation Solution
Incorporating a clarifier, such as bisphenols, bisphenol alkoxylates, or sulfonyl diphenols, into the polyester polyol composition, alongside a diol and optionally a hydrophobe, to enhance transparency and stability, with the clarifier being present in amounts ranging from 0.1 to 50 wt.%, allowing the polyol to retain clarity for weeks or months.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If hydrophobe modification is used to produce polyester polyols from recycled thermoplastics, then the polyol can be made from sustainable sources, but the product becomes opaque which is undesirable for polyurethane formulations
Solution Approach 1:
The patent introduces clarifiers as intermediary substances that mediate between the hydrophobe-modified polyester polyol and the desired clarity. These clarifiers (such as hydrophilic polymers, surfactants, or optical brighteners) do not fundamentally change the hydrophobe modification process but instead counteract its opaque effect, allowing both sustainable content and clarity to coexist
Solution Approach 2:
The patent modifies physical or chemical parameters of the polyol system by adjusting clarifier concentration, molecular weight, and chemical structure to optimize clarity while maintaining sustainable content. By changing these parameters, the patent resolves the contradiction between hydrophobe modification (for sustainability) and optical clarity
2Illumination intensity
If clarifiers are added to maintain clarity, then transparency is improved, but the formulation complexity increases
Solution Approach 1:
The patent selects clarifiers that perform multiple functions simultaneously: they provide optical clarity, maintain polyol stability, and do not interfere with polyurethane curing. This multi-functionality reduces formulation complexity by eliminating the need for separate additives for each function
Solution Approach 2:
The patent creates a composite formulation system where the clarifier is integrated with the hydrophobe-modified polyester polyol matrix. This composite approach allows the clarifier to work synergistically with other components rather than as a separate additive, simplifying the overall formulation
3Strength
If high aromatic ring content is used in recycled PET, PBT, and PTT, then strength and thermal stability are improved, but clarity deteriorates over time
Solution Approach 1:
The patent applies clarifiers during the polyol synthesis process itself, rather than as a post-processing step. This preliminary action ensures that clarity is built into the polyol structure from the beginning, preventing aromatic-induced opacity from developing over time while maintaining the strength-providing aromatic content
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 approach results in polyester polyols with improved hydroxyl numbers, viscosities, and functionalities, maintaining transparency and stability, making them suitable for various polyurethane applications while reducing reliance on petrochemical sources, with a high recycle content and bio-renewable content, thus offering a sustainable alternative.
Implementation Method 1
Incorporating a clarifier, such as bisphenols, bisphenol alkoxylates, or sulfonyl diphenols, into the polyester polyol composition... to enhance transparency and stability, with the clarifier being present in amounts ranging from 0.1 to 50 wt.%, allowing the polyol to retain clarity for weeks or months
Data Source
AI summary
Polyester polyols, processes for making them, and applications for the polyols are disclosed. Some of the polyols comprise recurring units from a digested thermoplastic polyester (e.g., recycled polyethylene terephthalate), a diol, an optional hydrophobe, and a clarifier. The clarifier, which in some cases is a bisphenol, bisphenol alkoxylate, bisphenol polycarbonate, sulfonyl diphenol, or sulfonyl diphenol alkoxylate, helps the polyol remain clear for weeks or months after its preparation. In some aspects, the clarifier is a monophenol, bisphenol, or poly-phenol having two or more phenylene rings wherein at least two of the phenylene rings lack a common molecular axis. The clarifier may also be an alkylated phenol, an epoxy resin, an epoxy novolac resin, a diphenylmethane, or a tris(aryloxy)phosphate. The polyols are valuable for formulating a variety of polyurethanes and related products—including polyurethane dispersions, flexible and rigid foams, coatings, adhesives, sealants, and elastomers—and they provide a sustainable alternative to bio- or petrochemical-based polyols.