Flexible Heater PTC Ink Composition Without NTC Behavior
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Solution Overview
Problem
Existing PTC materials face issues such as immediate transition to NTC behavior, low resistance magnification, resistance hysteresis, and resistance recovery time, leading to safety risks and poor temperature regulation in applications like electrically heated fabrics.
Innovation Solution
Development of a high-resistance magnification (HRM) PTC ink with a resistance magnification of at least 15 in a temperature range of at least 20 degrees Celsius above the switching temperature, eliminating NTC effects and providing precise temperature regulation through a steep resistance transition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional PTC materials are used, then current limitation function is achieved, but NTC behavior occurs immediately after PTC characteristics causing safety risks and self-burning
Solution Approach 1:
The patent extracts and eliminates the NTC behavior from the PTC material system by using a specially formulated ink composition containing PTC particles dispersed in a polymer matrix with specific glass transition temperature, achieving pure PTC characteristics without the harmful subsequent NTC effect that causes self-burning
Solution Approach 2:
The patent employs a composite material system consisting of PTC particles (such as barium titanate or lead zirconate titanate) dispersed in a polymer matrix (such as polyvinylidene fluoride or polyacrylonitrile), where the composite structure enables sustained PTC behavior and eliminates the NTC effect through proper material selection and formulation
2Manufacturing precision
If conventional PTC materials are used, then heating function is achieved, but resistance magnification is low (5-15) resulting in power dissipation and poor temperature regulation
Solution Approach 1:
The patent changes the key parameter of resistance magnification from the conventional 5-15 range to a higher range of 15-50 or more by optimizing the ink composition, particle concentration, and polymer matrix properties, thereby reducing power dissipation and improving temperature regulation precision
Solution Approach 2:
The patent utilizes the phase transition characteristics of the polymer matrix at its glass transition temperature to enhance the resistance magnification effect, where the phase change in the polymer surrounding the PTC particles amplifies the overall resistance change and improves temperature control
3Adaptability or versatility
If conventional PTC materials are used, then heating function is achieved, but transition region width varies with ambient temperature affecting operational characteristics
Solution Approach 1:
The patent enables the heater to self-adjust to different ambient temperatures by designing the PTC ink with a switching temperature and transition region that automatically adapt to environmental conditions, maintaining consistent operational characteristics across varying temperatures through the material's intrinsic properties
4Reliability
If conventional PTC materials are used, then heating function is achieved, but resistance hysteresis occurs causing partial resistance increase over time
Solution Approach 1:
The patent extracts and eliminates the resistance hysteresis phenomenon from the PTC material by using a properly formulated ink system where PTC particles are dispersed in a polymer matrix with appropriate glass transition temperature, preventing the time-dependent resistance increase that occurs in conventional materials
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 HRM PTC ink ensures safe operation by eliminating NTC effects, offering high resistance magnification, and enabling precise temperature control with rapid response times, reducing power consumption and enhancing application reliability.
Implementation Method 1
The terms positive temperature coefficient (PTC) materials and positive temperature coefficient of resistivity (PTCR) materials, as used herein, refer to materials that increase resistivity nonlinearly when their temperature is raised
Implementation Method 2
Another problem with current polymeric PTC materials is a low resistance magnification at the switch temperature, typically ranging from 5-15. This results in some power dissipation even at maximum resistance which results in poor temperature regulation
Data Source
AI summary
There is provided a process of manufacturing an article comprising: depositing a double-resin ink on a flexible substrate to form a flexible heater, wherein the double-resin ink comprises (i) a first resin comprising a crystalline or a semi-crystalline polymer; and (ii) a second resin comprising a non-crystalline polymer, wherein the double-resin ink has a positive temperature coefficient (PTC) and a resistance magnification of at least 20 in a temperature range of at least 20° C. above a switching temperature of the double-resin ink, the resistance magnification being defined as a ratio between a resistance of the double-resin ink at a temperature ‘T’ and a resistance of the double-resin ink at 25° C.; encapsulating the flexible heater in a dielectric ink; and inserting or attaching the flexible heater to an article selected from the group consisting of: heating pads; heat wraps; heated blankets; heated throws; heated body pillows; and heated mattress pads.