Liquid Crystal Polyester Welded Pipe Joints With Stronger Welds
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Solution Overview
Problem
Liquid crystal polyester has a high solidification rate during welding, leading to interface flow and the generation of new interfaces, making it difficult to join moldings and resulting in insufficient strength at welded parts.
Innovation Solution
A method for manufacturing welded moldings using liquid crystal polyester as a formation material, involving specific combinations of aromatic hydroxycarboxylic acids, aromatic dicarboxylic acids, and aromatic diols, with a flow start temperature of 280°C or higher, and incorporating a filling material like glass fibers, which are heat-welded to ensure strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If liquid crystal polyester is used as injection molding material, then excellent melting fluidity, heat resistance, strength, and rigidity are achieved, but high solidification rate causes interface flow and new interface generation at joint surfaces, making welding difficult
Solution Approach 1:
The patent changes the chemical composition parameters of liquid crystal polyester by specifying particular repeating units (formulae 1-3) and their molar ratios. This parameter optimization adjusts the molecular structure to reduce solidification rate while maintaining strength and rigidity, enabling successful welding without compromising mechanical properties.
Solution Approach 2:
The patent creates a composite material system by combining liquid crystal polyester with specific additives and modifiers. This composite approach allows the base polymer to maintain its excellent mechanical properties while the added components adjust the solidification characteristics to prevent interface flow during welding operations.
2Ease of manufacture
If welding is performed on liquid crystal polyester moldings, then components can be joined, but insufficient strength at welded parts occurs due to high solidification rate and interface flow
Solution Approach 1:
The patent optimizes welding process parameters including temperature control during welding to be below the flow start temperature, welding speed, and pressure application. These parameter changes prevent premature solidification and interface flow, ensuring adequate strength at welded joints while maintaining ease of manufacturing through welding.
Solution Approach 2:
The patent performs preliminary surface treatment on the liquid crystal polyester components before welding. This includes surface cleaning, activation, or coating with specific agents that enhance weldability. By preparing the surfaces in advance, the welding process can proceed effectively without compromising joint strength despite the material's high solidification rate.
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 method produces a highly reliable welded molding with enhanced strength at the welded parts, suitable for applications requiring high reliability, such as pipes.
Implementation Method 1
liquid crystal polyester, the resin having a repeating unit represented by general formula (1), a repeating unit represented by general formula (2), and a repeating unit represented by general formula (3)
Implementation Method 2
liquid crystal polyester has a high solidification rate at the time of melting, and solidifies while interface flow occurs at a joint interface at the time of welding
Implementation Method 3
the resin having a flow start temperature of 280°C or higher
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
A method for manufacturing a welded molding made of liquid crystal polyester as a formation material is provided, the method including: a step of heating each of a first ridge portion of a first member made of the liquid crystal polyester as a formation material and a second ridge portion of a second member made of the liquid crystal polyester as a formation material to a temperature equal to or higher than a flow start temperature of the liquid crystal polyester; and a step of abutting the first ridge portion and the second ridge portion to each other to perform vibration welding while pressing the first ridge portion and the second ridge portion in a direction in which the first ridge portion and the second ridge portion are brought relatively close to each other.