Weatherable PVC Sheet with Wolfram Cesium Heat Insulation
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Solution Overview
Problem
Conventional heat-insulating transparent polyvinyl chloride (PVC) sheets have a short service life due to inferior weatherability, leading to rapid decay in visible light transmittance and infrared blocking capabilities, and are associated with environmental issues and high production costs.
Innovation Solution
A weatherable PVC sheet is developed with a composition including polyvinyl chloride resin, plasticizer, epoxidized soybean oil, ultraviolet absorber, coupling agent, and a heat-insulation paste made from wolfram cesium powder, dispersant, and plasticizer, ground to nano-sized particles, which is processed using calendering, T-Die, or blow-molding to achieve excellent weatherability and self-adhesive properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional dry-coating or wet-coating processes are used to produce heat-insulating transparent PVC sheets, then the sheets can block infrared and ultraviolet wavelengths, but the sheets experience rapid decay in visible light transmittance and infrared blocking properties, resulting in short service life
Solution Approach 1:
The patent changes the chemical composition parameters by introducing specific weather-resistant additives including hindered amine light stabilizers (0.5-5.0 parts per hundred resin), ultraviolet absorbers (0.5-5.0 parts per hundred resin), and antioxidant packages (0.5-5.0 parts per hundred resin) to the PVC formulation. These compositional parameter changes enable the sheet to maintain its optical and thermal properties after 300 hours of QUV weathering with decay less than 5%, thereby resolving the contradiction between reliability and compositional stability.
Solution Approach 2:
The patent creates a composite material system by combining PVC resin with multiple functional additives: heat-insulating inorganic particles (ATO, AZO, or LaB6 at 5.5-7.5 PHR), weather-resistant stabilizers, ultraviolet absorbers, and antioxidants. This composite formulation synergistically provides both heat insulation and weather resistance, solving the contradiction by integrating multiple functions into a single material system that maintains performance over time.
2Temperature
If metal oxides like ATO, AZO, or hexaborides like LaB6, CeB6 are used for heat-insulation, then infrared blocking capability is achieved, but the heat-insulation effect decays quickly due to inferior weatherability
Solution Approach 1:
The patent introduces weather-resistant stabilizers (hindered amine light stabilizers, ultraviolet absorbers, and antioxidants) as intermediary protective agents that shield the heat-insulating metal oxide particles from environmental degradation. These stabilizers act as mediators between the infrared-blocking particles and the harsh outdoor environment, preventing the particles from losing their heat-insulation effect and thereby extending the duration of the heat-insulation capability.
Solution Approach 2:
The patent optimizes the particle size parameters of the heat-insulating metal oxide particles (ATO, AZO, or LaB6) to 40-110 nm nano-sized range and controls their concentration at 5.5-7.5 PHR. These parameter changes enhance both the infrared blocking efficiency and the weatherability of the particles, allowing them to maintain their heat-insulation effect for extended periods (300+ hours QUV testing with less than 5% decay).
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 weatherable PVC sheet maintains high transparency and infrared shielding ability with minimal decay over 300 hours, suitable for various applications, including building glass and greenhouse films, while reducing environmental impact and production costs.
Implementation Method 1
an ultraviolet absorber (e)
Implementation Method 2
block infrared (IR) as well as ultraviolet (UV)... infrared-blocking property... infrared cut rate
Data Source
AI summary
A heat-insulating transparent PVC sheet is formed from a PVC substrate having a thickness of 0.02-2.0 mm and contains heat-insulation pastes evenly distributed over the PVC substrate, since the heat-insulation paste contains an essential component of wolfram cesium powder (WCs) with a chemical formula of CsXNYWO3-ZClC and having a particle size of 0.005-2 μm, the heat-insulating transparent PVC sheet has an excellent weatherability, and particularly before and after tested in 300-hour service life in line with ASTM G-154 specification, has a physical property of weatherability decay rate (%) small than 4%.