Liquid Crystalline Polyester Molded Articles with Blister-Free Release
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Solution Overview
Problem
Liquid crystalline polyester compositions used in melt molding often experience mold releasing failures, leading to deformation and blister formation during soldering treatments, which complicates the production of complex-shaped electronic parts.
Innovation Solution
A liquid crystalline polyester composition with a solubility parameter range of 13 to 13.6 cal/cm3/2 and a polyhydric alcohol fatty acid ester with a solubility parameter range of 9 to 9.5 cal/cm3/2, where the difference between the two parameters is between 3.8 and 4.6 cal/cm3/2, is used to enhance mold releasing properties and prevent blister formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If ester of pentaerythritol stearic acid is used as an internal release agent, then mold releasing property is improved, but blister formation occurs during soldering treatment
Solution Approach 1:
The patent changes the chemical parameters of the release agent by specifying a particular ester of pentaerythritol stearic acid with controlled purity (95% or more) and specific molecular structure. This parameter control prevents blister formation during soldering while maintaining good mold releasing properties, resolving the contradiction between ease of operation and harmful effects.
Solution Approach 2:
The patent applies the release agent selectively at the interface between the molded article and mold cavity, ensuring that the release function is localized where needed. The controlled distribution and concentration of the ester at this interface provide effective release without causing blistering during subsequent soldering operations.
2Ease of operation
If chemical agent coating is applied to die inner surface, then mold releasing property is improved, but productivity is reduced due to repeated application requirements
Solution Approach 1:
The patent incorporates the release agent directly into the liquid crystalline polyester composition, allowing the material to self-release from the mold cavity through its inherent properties. This eliminates the need for external chemical agent applications and the associated productivity losses, as the release function is built into the material itself.
Solution Approach 2:
The patent merges the release agent with the liquid crystalline polyester base material, creating a unified composition where the release properties are integrated rather than applied separately. This combination eliminates the need for separate coating operations and maintains continuous productivity.
3Ease of manufacture
If liquid crystalline polyester is used for complex-shaped parts, then fluidity and moldability are improved, but mold releasing failure occurs easily
Solution Approach 1:
The patent modifies the chemical composition parameters of the liquid crystalline polyester by adding the specific ester of pentaerythritol stearic acid. This compositional change maintains the excellent fluidity and moldability of the base material while introducing release properties that prevent sticking to complex mold cavities, resolving the contradiction between ease of manufacture and ease of operation.
Data Source
AI summary
The present invention provides a liquid crystalline polyester composition comprising (A) a liquid crystalline polyester having a solubility parameter σA of from 13 (cal/cm3)1/2 to 13.5 (cal/cm3)1/2 and (B) a polyhydric alcohol fatty acid ester having a solubility parameter σB of from 9 (cal/cm3)1/2 to 9.5 (cal/cm3)1/2, wherein the component (B) is contained in the amount of from 0.1 to 1 parts by weight on the basis of 100 parts by weight of the component (A). The composition has a good mold releasing property to dies in a melt molding at the time of producing a molded article by melt molding the composition and providing a molded article with sufficiently reduced blisters.