Decorative Sheet Storage Modulus Control for Stable Pre-Molding
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional decorative sheets face issues with moldability due to insufficient heating leading to whitening or cracks, and excessive heating causing crystal melting or foaming, with a narrow allowable temperature range during molding.
Innovation Solution
A decorative sheet comprising a substrate layer and a thermoplastic resin layer, where the storage modulus ratio is adjusted to ensure a wide temperature range, improving moldability and preventing defects like whitening or cracks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the decorative sheet is sufficiently heated during pre-molding to improve conforming to the mold, then moldability is improved, but excessive heating may cause crystal melting, foaming, or other defects
Solution Approach 1:
The patent applies parameter changes by carefully controlling the heating temperature and time during pre-molding to optimize the softening of the thermoplastic resin layer. The storage modulus ratio specification (3.5 or less) defines a specific parameter range that ensures the material softens sufficiently for good moldability while remaining below the threshold for crystal melting and foaming, thus resolving the contradiction between achieving good conforming and avoiding thermal degradation
Solution Approach 2:
The patent employs preliminary anti-action by pre-defining the storage modulus ratio characteristic before the molding process. This pre-established material property ensures that during pre-molding, the decorative sheet will soften to an optimal degree without exceeding safe temperature limits, thereby preventing crystal melting and foaming before they can occur
2Object-affected harmful factors
If the decorative sheet is not sufficiently heated during pre-molding, then thermal degradation is avoided, but whitening or cracks occur at the edges due to insufficient conforming
Solution Approach 1:
The patent uses parameter changes by specifying a precise storage modulus ratio (3.5 or less) that defines the optimal softening state of the thermoplastic resin layer. This parameter ensures that during pre-molding, the material achieves sufficient softening to conform to the mold edges without overheating, thereby preventing both whitening/cracks from insufficient heating and degradation from excessive heating
Solution Approach 2:
The patent replaces direct mechanical control of heating parameters with a material property-based approach. Instead of controlling the pre-molding process through mechanical temperature and time parameters alone, the invention uses the storage modulus ratio as a substitute parameter that inherently guides the heating process to the optimal range, eliminating the need for complex temperature control mechanisms
3Object-affected harmful factors
If the decorative sheet is molded in a low-fluidity state, then thermal degradation is prevented, but uneven sheet thickness occurs after pre-molding
Solution Approach 1:
The patent applies parameter changes by defining the storage modulus ratio (3.5 or less) as the controlling parameter for material fluidity during pre-molding. This parameter ensures the thermoplastic resin layer achieves optimal fluidity for uniform thickness distribution while maintaining temperature below the threshold for thermal degradation, crystal melting, and foaming
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 decorative sheet achieves improved moldability and a wide allowable temperature range, reducing the likelihood of defects such as whitening, cracks, and uneven thickness, while maintaining heat resistance.
Implementation Method 1
when the decorative sheet changes from the transition region to a rubbery flat region
Implementation Method 2
a storage modulus is measured for the prepared test piece with an initial chuck distance of 10.77 mm, at a start temperature of 30° C., an end temperature of 150° C.
Implementation Method 3
when the decorative sheet is not sufficiently heated during pre-molding and the decorative sheet is not sufficiently softened
Data Source
AI summary
A decorative sheet comprises a substrate layer; a pattern layer provided on the first front surface of the substrate layer; and a thermoplastic resin layer provided on the second front surface of the pattern layer. A test piece of 8 mm width from the decorative sheet is taken; the storage modulus is measured with an initial chuck distance of 10.77 mm, a start temperature of 30° C., an end temperature of 150° C., a temperature increase rate of 5° C./min, and a measurement frequency of 1.0 Hz. The ratio of the difference between the second storage modulus and a third storage modulus when the decorative sheet changes from the transition region to a rubbery flat region to the difference between a first storage modulus when the environmental temperature is 30° C. and a second storage modulus when the decorative sheet changes from a glassy region to a transition region is 3.5 or less.