Composite Prepreg Tack Layer for Wide-Temperature Adhesion
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Solution Overview
Problem
Curable resin systems used in prepregs exhibit limited tackiness over a narrow temperature range and are affected by aging, making them unpredictable for use in composite materials applications.
Innovation Solution
A porous sheet material impregnated with a polymer having a glass transition temperature of less than 0°C is applied to the surface of prepregs to enhance tackiness over a wider temperature range, from -10°C to 10°C, and maintain adhesion over time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If curable resin systems are used to provide tack in prepregs, then adhesion between plies is improved, but the temperature range over which usable tack is provided is limited to a narrow ambient range
Solution Approach 1:
The invention uses a composite tack material comprising a porous sheet material impregnated with a polymer material having a glass transition temperature of less than 0°C. This composite structure combines the adhesive properties of the polymer with the structural support of the porous sheet, providing tack over a wide temperature range from -10°C to 10°C while maintaining adhesion between plies.
Solution Approach 2:
The invention changes the glass transition temperature parameter of the tack material by selecting a polymer material with Tg < 0°C. This parameter change allows the material to maintain tack properties at lower temperatures compared to conventional curable resin systems, thereby expanding the usable temperature range for lay-up operations.
2Strength
If curable resin systems are used to provide tack in prepregs, then initial adhesion is achieved, but the degree of tackiness reduces noticeably over time due to aging
Solution Approach 1:
The invention employs a polymer material with low glass transition temperature that provides temporary tack during the lay-up process and early curing stages, but is designed to become less tacky as curing progresses. This allows the material to fulfill its adhesive function during handling while naturally relinquishing tack as the structural resin takes over, providing stable long-term adhesion without prolonged tackiness.
3Ease of operation
If the degree of tackiness is increased to improve handling, then adhesion over a wider temperature range is achieved, but the material complexity increases
Solution Approach 1:
The invention uses a porous sheet material as the base structure for the tack material. The porous structure provides mechanical support and structural integrity while allowing the polymer material to be impregnated within the pores. This design maintains relative simplicity by using a straightforward porous substrate-polymer impregnation structure rather than complex multilayer or composite constructions.
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 solution increases the surface tack of prepregs and laminates, providing improved handling and processing characteristics over a broader temperature range and extended shelf life, with adhesion levels maintained within 25% of original values after 5 to 30 days.
Implementation Method 1
the tack material comprises a porous sheet material at least partially impregnated with a polymer material having a glass transition temperature of less than 0°C
Data Source
Figure 1~2
AI summary
A structure or laminate comprising a fibrous reinforcement material and a reinforcement resin material are described, wherein the structure or laminate further comprises a tack material, the tack material increasing the surface tack of the structure or laminate over a tack temperature range of from -10°C to 50°C in comparison to the original surface tack of the structure or laminate in the absence of the tack material over the same tack temperature range.