Segmented Polyurethane Pultrusion for High Tg and Pot Life
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing polyurethane pultrudate manufacturing processes face challenges in achieving suitable processing conditions with long processability and high product properties such as glass transition temperature and modulus, due to unsuitable pot life and gel time ranges.
Innovation Solution
A two-phase mixture of polyether polyols with specific hydroxyl number ranges and chain extenders, combined with organic polyisocyanates and epoxides, is reacted in the presence of catalysts and reinforcing fibers using the pultrusion technique, with curing at elevated temperatures and controlled proportions to achieve desired mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a high crosslinking density is set to achieve a high glass transition temperature, then the glass transition temperature is improved, but the pot life or gel time decreases to an unsuitable range
Solution Approach 1:
The patent segments the polyol system into two distinct phases: a low-viscosity phase (polyether polyol with OH number 15-50) and a high-viscosity phase (polyether polyol with OH number 150-600 mixed with chain extenders/crosslinkers). This segmentation allows each phase to fulfill different functions - the low-viscosity phase ensures long pot life and good impregnation, while the high-viscosity phase provides high crosslinking density and glass transition temperature.
Solution Approach 2:
The patent changes the parameter of hydroxyl number distribution in the polyol system. By using a specific combination of polyether polyols with OH numbers in the range of 15-50 and 150-600, the system achieves optimal balance between processability (long pot life) and final product properties (high glass transition temperature). The epoxide content is also controlled within 5-50 wt% to optimize the balance between crosslinking density and pot life.
2Strength
If a high crosslinking density is set to achieve high product properties, then the modulus is improved, but the processability decreases
Solution Approach 1:
The patent divides the resin system into two functional segments: a low-viscosity segment (polyether polyol with OH number 15-50) that provides excellent processability and fiber impregnation, and a high-crosslinking segment (polyether polyol with OH number 150-600 combined with chain extenders and epoxides) that delivers high modulus and glass transition temperature. This segmentation resolves the contradiction between ease of manufacture and final product strength.
Solution Approach 2:
The patent creates a composite resin system combining multiple polyether polyols with different OH numbers, chain extenders, epoxides, and polyisocyanates. This composite approach allows the system to exhibit both good processability (from the low-viscosity component) and high mechanical properties (from the high-crosslinking components), achieving optimal balance between ease of manufacture and product performance.
3Duration of action of moving object
If the pot life is extended to ensure sufficient fiber impregnation, then the processing time is improved, but the gel time increases beyond suitable ranges
Solution Approach 1:
The patent segments the polyol mixture into low-viscosity (OH number 15-50) and high-viscosity (OH number 150-600) components. The low-viscosity segment dominates the flow characteristics, extending processing time and ensuring complete fiber impregnation, while the high-viscosity segment contains the crosslinking agents that control gel time. This segmentation allows independent optimization of both processing time and gel time.
Solution Approach 2:
The patent optimizes the parameter of polyol viscosity distribution by selecting specific OH number ranges. The low OH number polyether polyol (15-50) provides extended processing time and good impregnation, while the high OH number polyether polyol (150-600) combined with controlled epoxide content (5-50 wt%) ensures appropriate gel time. This parameter optimization resolves the contradiction between processing time and gel time.
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 process results in polyurethane pultrudates with high glass transition temperatures and moduli, along with extended processability, as demonstrated by examples showing improved mechanical properties and gel times.
Implementation Method 1
reacting a) one or more polyether polyols with an OH number of 15 to 50 based on propylene oxide and b) a mixture of one or more polyether polyols with an OH number of 150 to 600 and one or more chain extenders and/or crosslinkers with an OH number of 700 to 1827 and B) one or more epoxides with C) organic polyisocyanates
Implementation Method 2
D) optionally catalysts
Implementation Method 3
an at least two-phase mixture of non-homogeneously miscible components a) and b)
Data Source
AI summary
The invention relates to reinforced pultruded polyurethane and to a method for the production thereof by pultrusion.