Highly Filled Composite Article Curing with Controlled Exotherm
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Highly filled composite materials, such as agglomerated stone and fiber-reinforced systems, face issues with insufficient heat generation during curing due to low resin content, leading to deformation and cracks, and require a longer potlife that conventional ketone peroxides cannot provide, while peroxyesters cause high peak exotherms.
Innovation Solution
A process using a combination of peroxyester and organic hydroperoxide, with a specific weight ratio and absence of ketone peroxide, is employed to cure the composite at moderate temperatures (60-100°C), ensuring a controlled exotherm and adequate potlife.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If ketone peroxide is used as the curing agent, then the potlife is extended, but the peak exotherm becomes too high causing deformation and cracks
Solution Approach 1:
The curing system is segmented into two distinct components: a ketone peroxide component (providing long potlife) and a peroxyester component (providing controlled exotherm). Each peroxide type performs a specific function, and their combined effect resolves the contradiction between extended potlife and controlled peak exotherm.
Solution Approach 2:
The invention changes the chemical parameters of the curing system by selecting specific peroxide types (ketone peroxide and peroxyester) with different decomposition characteristics and optimizing their weight ratio (0.5:99.5 to 50:50). This parameter optimization allows simultaneous achievement of extended potlife and controlled peak exotherm.
2Quantity of substance
If the resin content is reduced to achieve high filler content, then the composite strength is improved, but the heat generation during curing becomes insufficient
Solution Approach 1:
The invention introduces an external heat source as an intermediary to compensate for the insufficient heat generation in highly filled composites. This external heating enables the curing reaction to proceed despite the low resin content, allowing high filler content (90-99 wt%) to be achieved without sacrificing cure completeness.
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 achieves a low peak exotherm, preventing deformation and cracks, and provides a suitable curing time, resulting in high-quality composite articles.
Implementation Method 1
The curing reaction is initiated at room temperature by the joint action of peroxide and accelerator and can proceed by the heat that is produced during the exothermic curing reaction
Implementation Method 2
the heat that is produced during the exothermic curing reaction
Implementation Method 3
heating the shaped mixture at a temperature in the range 60-100°C to affect hardening of the resin
Data Source
AI summary
Process for the production composite articles, comprising the steps of: a)providing a curable mixture comprising: -30-95 wt% of filler material, -5-70 wt% of resin, selected from unsaturated polyester resins, vinyl ester resins, (meth)acrylate resins, and combinations thereof, -0.5-10 phr of at least one peroxyester, -0.1-2.0phr of at least one organic hydroperoxide, the weight ratio peroxyester/organic hydroperoxide being below 14.0, the curablemixture being essentially free of ketone peroxide, b)shaping the mixture, and c)heating the shaped mixture at a temperature in the range 60-100°C to affect hardening of the resin and the formation of an article.