Polycarbonate Panel with PMMA Layer for Weatherability

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Solution Overview

Problem

Polycarbonate glazing in automotive vehicles faces challenges such as poor weatherability, abrasion, and degradation due to its expansion and contraction characteristics, which are not present in glass glazing, necessitating a solution that maintains high impact strength and weather resistance without compromising material integrity.

Innovation Solution

A plastic panel comprising a polycarbonate substrate and a polymethylmethacrylate (PMMA) layer with UV absorbing materials, along with scratch-resistant coatings, is used to enhance weathering and impact resistance, with the PMMA layer forming a protective barrier against environmental elements and the polycarbonate providing structural support.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If polycarbonate is used for automotive glazing, then impact strength and transparency are improved, but weatherability and abrasion resistance deteriorate

Engineering Contradiction:
Improveimpact strengthVSAvoidweatherability
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent applies composite materials by combining polycarbonate substrate with multiple protective layers including PMMA (polymethyl methacrylate) and UV-protective coatings. This composite structure allows the polycarbonate to provide impact strength while the protective layers provide weatherability and abrasion resistance, resolving the contradiction between these properties.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent uses intermediate protective layers (PMMA and UV-protective coatings) as mediators between the polycarbonate substrate and the external environment. These intermediary layers protect the polycarbonate from UV radiation and environmental degradation while allowing the polycarbonate to maintain its impact strength properties.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Illumination intensity

If polycarbonate is used for automotive glazing, then high transparency is achieved, but expansion and contraction characteristics cause degradation

Engineering Contradiction:
ImprovetransparencyVSAvoiddimensional stability
Core Design Contradiction:
Illumination intensityVSStability of the object's composition

Solution Approach 1:

The composite structure with protective layers compensates for the dimensional instability of polycarbonate. The protective layers constrain the expansion and contraction of the polycarbonate substrate, maintaining dimensional stability while preserving the high transparency of the polycarbonate material.

Inventive Principle:
Principle #40Composite materials

3Reliability

If UV protective varnish is applied to polycarbonate, then weatherability is improved, but the varnish degrades over time leaving the material vulnerable

Engineering Contradiction:
ImproveweatherabilityVSAvoidprotection duration
Core Design Contradiction:
ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The patent uses a composite protective system with multiple layers (PMMA and UV-protective coatings) instead of a single varnish layer. This multi-layer composite provides prolonged protection duration as the layers work together to resist environmental degradation, with the PMMA layer providing structural protection and the UV-coating providing chemical protection against UV radiation.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent changes the parameters of the protective layer by using PMMA with specific thickness ranges (0.25mm to 3.0mm) and combining it with UV-absorbing materials. This parameter optimization ensures long-term durability and extended protection duration beyond what single-layer varnishes can provide.

Inventive Principle:
Principle #35Parameter changes

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 provides a lightweight, stylish, and robust plastic panel with improved weatherability and impact resistance, protecting the polycarbonate substrate from environmental degradation and internal impacts, while maintaining structural integrity and filtering UV light.

Implementation Method 1

a polymethylmethacrylate (PMMA) layer (14) with UV absorbing materials (17) disposed onto, and bonded to, the polycarbonate substrate (12)

Methodology Applied
Scientific EffectUV absorption: Absorption (EM radiation)

Data Source

PatentEP3075584B1Automotive plastic panel
Publication Date: 2021.05.26 FLEX N GATE LLC
  • EP3075584B1 patent drawingFigure 1~3
  • EP3075584B1 patent drawingFigure 4~6

AI summary

A plastic panel (10) suitable for use in an automotive vehicle or other structure is provided wherein the plastic panel (10) includes a polycarbonate substrate (12), a PMMA layer (14) and a scratch resistant coating (15). The polycarbonate substrate (12) may have a thickness approximately between 2.0 mm and approximately 6.0 mm. The PMMA layer (14) may be disposed onto the polycarbonate substrate (12) and the PMMA layer (14) may have a thickness approximately between 0.25 mm and approximately 3.0 mm. The scratch resistant coating (16) may be applied to both the PMMA layer (14) and the polycarbonate substrate (12).