PCM Fiber Extrusion with Quenching to Prevent Bubble Formation
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Solution Overview
Problem
Existing methods for producing fibrous or film-like molded articles with high heat storage capacity for textile applications face issues such as bubble formation, fiber tears, and limited PCM content due to poor miscibility and surface defects, leading to exudation and structural weaknesses.
Innovation Solution
A process involving a plasticized mixture of 60-10% carrier component and 40-90% phase change material, with the carrier component comprising LDPE, HDPE, PMMA, or polycarbonate, and styrene block copolymers, is extruded into moldings and quenched within 0.05-4 seconds to prevent paraffin evaporation and enhance PCM distribution, using a twin-screw extruder and quenching in a cooling bath to achieve high heat storage capacity and mechanical strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If paraffin is used as phase change material in high proportions (40-90% by weight), then heat storage capacity is improved, but bubble formation and fiber tears occur due to evaporation and poor miscibility
Solution Approach 1:
The patent uses a specifically formulated carrier component as an intermediary substance between the phase change material and the polymer matrix. This carrier component, comprising polymer and styrene block copolymer in specific ratios, acts as a mediator that improves miscibility of paraffin in the polymer matrix, preventing bubble formation and fiber tears while enabling high PCM content (40-90% by weight) to be achieved without compromising fiber integrity.
Solution Approach 2:
The patent applies parameter changes by controlling the molecular weight, composition, and ratio of the carrier component and polymer matrix. By adjusting these parameters - specifically using carrier component with 5-50% by weight styrene block copolymer and controlling the PCM-to-carrier component ratio - the system achieves optimal miscibility and mechanical properties that prevent evaporation-related defects while maintaining high heat storage capacity.
2Ease of manufacture
If paraffin is heated during plasticization or melting, then phase change material becomes processable, but it evaporates and forms bubbles after exiting extrusion die
Solution Approach 1:
The carrier component serves as a protective intermediary that reduces the evaporation rate of paraffin during processing. By incorporating paraffin into the carrier component matrix with specific composition ratios, the system enables paraffin to remain processable at elevated temperatures while the carrier component structure prevents excessive evaporation and subsequent bubble formation after extrusion.
Solution Approach 2:
The patent creates a composite material system consisting of phase change material, carrier component, and polymer matrix. This composite structure allows the paraffin to be processed at temperatures suitable for phase change while the composite nature of the material - with carrier component and polymer providing structural integrity - prevents evaporation-induced bubble formation that would occur in simple paraffin-polymer blends.
3Quantity of substance
If PCM deposits close to the surface, then heat storage capacity is achieved, but liquefied PCM escapes through surface defects causing exudation
Solution Approach 1:
The patent employs a composite material system where the carrier component and polymer matrix form a cohesive network that encapsulates and stabilizes PCM deposits near the surface. This composite structure - with specific ratios of carrier component (5-50% by weight) and polymer - provides sufficient mechanical strength to contain liquefied PCM even when deposits are close to the surface, preventing exudation through minor surface defects while maintaining high heat storage capacity.
Solution Approach 2:
The patent applies local quality by creating regions of enhanced mechanical strength and PCM compatibility within the material structure. The carrier component, with its specific composition including styrene block copolymer, provides localized reinforcement around PCM deposits, particularly near the surface, enabling the material to contain liquefied PCM locally without requiring uniform reinforcement throughout the entire structure.
4Productivity
If conventional melt spinning processes are used, then fiber production is achieved, but filaments are torn off or broken due to bubbling
Solution Approach 1:
The patent applies parameter changes by optimizing the composition and properties of the carrier component and controlling processing parameters such as extrusion temperature, cooling rate, and draw ratio. These parameter adjustments - particularly using carrier component with controlled styrene block copolymer content (5-50% by weight) and specific molecular weight - eliminate bubble formation during conventional melt spinning, enabling high productivity fiber production without filament tears or breaks.
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 results in fibrous or film-like moldings with heat storage capacity of 70-270 J/g, high tensile strength, and low exudation losses, suitable for textile applications with improved durability and thermal properties.
Implementation Method 1
At the phase transition temperature of the phase change material (hereinafter abbreviated to PCM), the fibers or foils according to the invention (hereinafter also referred to as PCM fibers or foils) have a heat storage enthalpy of up to 230 J/g
Implementation Method 2
the PCM fibers/foils compensate for temperature changes by absorbing or releasing heat
Implementation Method 3
the plasticized mixture at a temperature of 130 to 220 °C through an extrusion die is extruded into fibrous or film-like moldings
Implementation Method 4
quenched within 0.05-4 seconds to prevent paraffin evaporation and enhance PCM distribution
Data Source
Figure 1
Figure 2
AI summary
Fiber-like or film-like moldings are produced from a plasticized mixture which, based on its weight, is composed of 60 to 10% by weight of a carrier component and 40 to 90% by weight of a phase change material wherein, based on the weight of the plasticized mixture, the carrier component contains 5 to 20% by weight of a polymer or polymer blend from the group comprising LDPE (low density polyethylene), HDPE (high density polyethylene), PMMA (polymethyl methacrylate), polycarbonate and mixtures thereof, 5 to 20% by weight of a styrene block copolymer and 0 to 20% by weight of one or more additives, and the phase change material is selected from the group comprising natural and synthetic paraffins, polyethylene glycol (= polyethylene oxide) and mixtures thereof, and the plasticized mixture is extruded through a spinneret or a slit die at a temperature of 130 to 220° C and is stretched.