Low Naphthenic Liquid Crystalline Polymer for Small Mold Cavities
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Solution Overview
Problem
Conventional liquid crystalline polymers used in electrical components have high solid-to-liquid transition temperatures, making it difficult to fill small mold cavities while maintaining good mechanical and thermal properties, and are costly due to the use of naphthenic acids as melting point suppressants.
Innovation Solution
A thermoplastic composition with a low naphthenic content, comprising thermotropic liquid crystalline polymers, hydroxy-functional compounds, and aromatic dicarboxylic acids, which reduces melt viscosity without compromising mechanical properties, allowing for the formation of small-dimensional molded parts with high flowability and excellent thermal and mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If naphthenic acids are used as melting point suppressants to lower the solid-to-liquid transition temperature, then the polymer can flow better at lower temperatures, but the cost increases and the reactivity with other monomers causes unintended consequences on mechanical and thermal properties
Solution Approach 1:
The patent removes naphthenic acid components from the polymer composition entirely, replacing them with alternative monomers that achieve the desired melting point suppression without the harmful side effects. This extraction of the problematic substance resolves the contradiction by eliminating cost increases and unwanted reactivity while maintaining the temperature reduction benefit through other means.
Solution Approach 2:
The patent changes the chemical composition parameters by using specific ratios of aromatic monomers (such as hydroxybenzoic acid, terephthalic acid, and other diacids/diols) to achieve melting point suppression without naphthenic acids. By adjusting these compositional parameters, the patent maintains flowability at lower temperatures while avoiding the cost and reactivity issues associated with naphthenic acid additives.
2Strength
If conventional liquid crystalline polymers with high melting temperatures are used, then good mechanical and thermal properties are maintained, but the ability to fill small mold cavities is precluded
Solution Approach 1:
The patent changes the thermal parameters of the polymer by carefully selecting and ratioing monomers with different melting characteristics. This allows the final polymer to have a reduced melting point that enables flow into small mold cavities, while the specific monomer selection ensures mechanical and thermal properties remain intact.
Solution Approach 2:
The patent creates a composite polymer system combining multiple aromatic monomers (hydroxybenzoic acid, terephthalic acid, isophthalic acid, and various diols) in specific proportions. This composite approach allows different monomer components to contribute different properties - some providing structural strength while others facilitate flow - resolving the contradiction between maintaining strength and achieving manufacturability in small parts.
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 composition achieves low melt viscosity, enabling the filling of small mold cavities while maintaining high impact strength, tensile strength, and thermal stability, suitable for applications in fine pitch electrical connectors and other small-dimensional components.
Implementation Method 1
conventional formulations are generally derived from aromatic hydroxy acid monomers... which tend to display a very high solid-to-liquid transition temperature ('melting temperature')
Implementation Method 2
at least one thermotropic liquid crystalline polymer
Data Source
AI summary
A thermoplastic composition that comprises a low-naphthenic, thermotropic liquid crystalline polymer blended with a combination of flow modifiers is provided. More particularly, one of the flow modifiers is a hydroxy-functional compound that contains or more hydroxyl functional groups. Without intending to be limited by theory, it is believed that the hydroxyl functional groups can react with the polymer chain to shorten its length and thus reduce melt viscosity. Aromatic dicarboxylic acids are also employed as a flow modifier in the thermoplastic composition. Again, without intending to be limited by theory, it is believed that such acids can combine smaller chains of the polymer together after they have been cut by hydroxy-functional compounds. This helps maintain the mechanical properties of the composition even after its melt viscosity has been reduced.