Sequential Polyol Esterification for Gel-Free Cosmetics
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Solution Overview
Problem
Cosmetic formulations face challenges in providing emolliency, humectancy, sun protection, and cost-effectiveness while avoiding undesirable reactive species and skin penetration, with existing materials like mineral oil and fatty esters failing to modify skin feel, flow, and film-forming properties effectively.
Innovation Solution
A series of polyesters are synthesized by sequentially reacting mono-hydroxy, di-hydroxy, and tri-hydroxy polyol esters with diacids using esterification chemistry, avoiding free radical reactions to create epigenomic-friendly compounds that stay on the skin without penetration or irritation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If all reactants are reacted together in a single step, then the manufacturing process is simpler, but the product forms a gel and becomes useless
Solution Approach 1:
The patent divides the polyesterification process into two separate stages: (1) pre-esterification of polyols with fatty acids to form mono-, di-, and tri-hydroxy esters, and (2) subsequent reaction of these esters with diacids. This segmentation prevents gel formation by controlling the sequence of reactions and maintaining proper stoichiometry throughout the process.
Solution Approach 2:
The patent performs preliminary esterification of polyols with fatty acids before the main polyesterification reaction with diacids. This preliminary action creates well-defined intermediate esters with controlled hydroxyl group distributions, which then react predictably with diacids to form linear polyesters rather than gelled networks.
2Productivity
If free radical chemistry is used for polymer synthesis, then the reaction proceeds quickly, but residual vinyl monomers remain which are undesirable and potentially harmful
Solution Approach 1:
The patent replaces free radical polymerization chemistry with step-growth esterification chemistry. This substitution eliminates the formation of vinyl monomers and associated harmful residues, while still achieving efficient polymer synthesis through condensation reactions between hydroxyl and carboxyl groups with water or alcohol elimination.
3Ease of operation
If low molecular weight compounds are used, then they penetrate the skin more easily, but this causes irritation and inflammation
Solution Approach 1:
The patent controls the molecular weight parameters of the polyester by adjusting the stoichiometry of reactants, the degree of polymerization, and the structure of starting materials. This produces high molecular weight polyesters that remain on the skin surface without penetrating into living layers, thereby providing cosmetic benefits without causing irritation or inflammation.
4Ease of manufacture
If existing materials like mineral oil and fatty esters are used, then the formulation is simple and cost-effective, but they fail to modify skin feel, flow, and film-forming properties
Solution Approach 1:
The patent creates composite polyester molecules combining fatty acid chains (from natural oils) with polyol backbones (containing multiple hydroxyl groups). This composite structure integrates the simplicity and cost-effectiveness of natural materials with the functional versatility needed to modify skin feel, flow properties, and film-forming characteristics.
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 polyesters provide desirable skin benefits with controlled molecular weight, preventing skin penetration and irritation, while offering adjustable properties for unique skin and sun care products through regulated structure and partition coefficient manipulation.
Implementation Method 1
A series of polyesters are synthesized by sequentially reacting mono-hydroxy, di-hydroxy, and tri-hydroxy polyol esters with diacids using esterification chemistry
Data Source
AI summary
The present invention is directed to a series of polyesters that are made by the reaction of a diacid with a pre-formed mono-hydroxy, di-hydroxy and optionally a tri-hydroxy ester of polyols selected from pentaerythritol, di pentearythritol trimethylolpropane and mixtures thereof. When reacted in the sequence shown, that is pre-formation of the mono-ester, di-ester and tri-ester, selection of the proper ratio of one to the other and then and only then reacted with the diacid, do these polyesters remain free of a gel and form cosmetically elegant oil phases.