Unsaturated Polyester Resin with Itaconate Esters for Low Styrene Emission
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Solution Overview
Problem
Unsaturated polyester resin compositions used for structural parts face challenges with styrene emission, leading to undesirable odors and potential toxicity, and existing homopolymerizable itaconic-based resins are unsuitable for construction due to mechanical integrity issues, being either too soft or brittle.
Innovation Solution
Development of unsaturated polyester resins with itaconate esters, featuring an acid value range of 25 to 75 mg KOH/g resin and a molar ratio of hydroxyl and carboxylic acid end groups from 1.1 to 3, synthesized using a standard process, which allows for improved mechanical properties and reduced styrene emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If styrene is used as copolymerizable reactive diluent in unsaturated polyester resin, then the resin can be copolymerized and applied for structural parts, but styrene emission causes undesirable odour and toxic effects
Solution Approach 1:
The patent changes the chemical composition parameters by introducing itaconate esters with specific acid values (25-75 mg KOH/g) and molar ratios of hydroxyl to carboxylic acid end groups (1.1 to 3), transforming the resin from copolymerizable to homopolymerizable while reducing styrene content
Solution Approach 2:
The patent extracts styrene from the resin composition or reduces its quantity to minimal levels, replacing it with itaconate esters that provide homopolymerizability, thereby eliminating the source of styrene emission while maintaining structural performance
2Object-affected harmful factors
If existing homopolymerizable itaconic-based unsaturated polyesters are used, then styrene emission is reduced, but the cured resin is either too soft or too brittle for construction purposes
Solution Approach 1:
The patent optimizes critical parameters including acid value (25-75 mg KOH/g), hydroxyl value (>25 mg KOH/g), molecular weight (300-10,000 Dalton), and glass transition temperature (-70°C to 100°C) to achieve the desired balance between mechanical integrity and reduced styrene emission
Solution Approach 2:
The patent specifies different optimal parameter ranges for different application requirements: higher acid values (30-75) and higher molecular weights (750-5000 Dalton) for improved mechanical strength, while maintaining homopolymerizability for styrene reduction
3Ease of manufacture
If standard unsaturated polyester synthesis process is used, then all raw materials can be mixed and condensed at higher temperatures, but it is difficult to achieve the precise acid value and molar ratio control required for optimal mechanical properties
Solution Approach 1:
The patent employs preliminary action by pre-selecting and preparing specific raw materials with controlled properties, then using standard synthesis procedures that naturally achieve the desired acid value (25-75) and molar ratio (1.1 to 3) ranges through the defined formulation approach
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 resin compositions exhibit suitable mechanical properties for construction purposes, including enhanced tensile and flexural strength, and a glass transition temperature range suitable for structural applications, while minimizing styrene emission and toxicity.
Implementation Method 1
synthesized using standard unsaturated polyester synthesis process in which all the raw materials for the resin are mixed and condensed at higher temperatures
Data Source
AI summary
The present invention relates to an unsaturated polyester resin comprising itaconate esters as reactive unsaturations, wherein the acid value of the resin is in the range of from 25 to 125 and the molar ratio of hydroxyl end groups and carboxylic acid end groups is in the range of from 0.33 to 3. In one embodiment, the molar ratio of hydroxyl end groups and carboxylic acid end groups is in the range of from 0.33 to 0.9. In another embodiment, the molar ratio of hydroxyl end groups and carboxylic acid end groups is in the range of from 1.1 to 3.