Foam molded product and method for producing the same
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Solution Overview
Problem
Existing foam molded products made from thermoplastic polyester elastomers suffer from reduced rebound resilience and poor surface smoothness due to non-foamed skin layers, leading to uneven surfaces and decreased performance.
Innovation Solution
A counter-pressure foam injection molding method is employed to control the foamed region of the surface layer, using thermoplastic polyester elastomers with specific hard and soft segments, and applying controlled pressure and gas infusion to produce a foam molded product with a uniform foamed state and controlled cell structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If core-back foam injection molding method is used to achieve high foaming, then foaming ratio is improved, but surface smoothness deteriorates due to non-foamed skin layers
Solution Approach 1:
The invention changes the molding parameters by applying counter-pressure during foam injection molding. Specifically, it controls the pressure conditions to prevent non-foamed skin layer formation while maintaining high foaming ratio, thereby achieving both high foaming and excellent surface smoothness simultaneously
Solution Approach 2:
The invention applies counter-pressure in advance during the injection molding process to prevent the formation of non-foamed skin layers. By maintaining pressure control throughout the molding process, it anticipates and prevents surface defects before they occur, ensuring both high foaming and smooth surface
2Quantity of substance
If core-back foam injection molding method is used to achieve high foaming, then foaming ratio is improved, but rebound resilience deteriorates
Solution Approach 1:
The invention optimizes pressure parameters during foam injection molding to achieve uniform cell structure throughout the product. By controlling counter-pressure, it ensures complete foaming including in skin layers, which maintains the elastomeric properties and rebound resilience while achieving high overall foaming ratio
3Manufacturing precision
If short-shot foam injection molding method is used to produce thin skin layer, then surface smoothness is improved, but foaming ratio deteriorates
Solution Approach 1:
Instead of using short-shot molding to achieve smooth surfaces (which sacrifices foaming ratio), the invention inverts the approach by using counter-pressure foam injection molding to achieve both smooth surfaces and high foaming ratio simultaneously. It proves that proper pressure control can eliminate skin layers while maintaining high foaming
4Ease of manufacture
If conventional foam injection molding is used, then production process is simple, but rebound resilience deteriorates due to non-foamed skin layers
Solution Approach 1:
The invention modifies the pressure parameters of conventional foam injection molding by implementing counter-pressure control. This parameter change prevents non-foamed skin layer formation, thereby maintaining rebound resilience while keeping the production process relatively simple and direct
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 results in a lightweight product with high rebound resilience, excellent surface smoothness, and improved heat and water resistance, suitable for high-reliability applications without the need for post-processing.
Implementation Method 1
a gas is infused into the cavity of a mold and a molten thermoplastic resin is injected under pressure
Implementation Method 2
applying controlled pressure and gas infusion to produce a foam molded product with a uniform foamed state and controlled cell structure
Data Source
AI summary
The present invention is to provide a thermoplastic polyester elastomer resin foam molded product which exhibits light weight, excellent rebound resilience and excellent surface smoothness. A foam molded product including a continuous phase formed of a resin component containing a thermoplastic polyester elastomer, wherein the thermoplastic polyester elastomer is prepared by bonding a hard segment and a soft segment, wherein the hard segment consists of polyester constituted from aromatic dicarboxylic acid and aliphatic and/or alicyclic diol as constituting components, wherein the soft segment is at least one member selected from a group consisting of aliphatic polyether, aliphatic polyester and aliphatic polycarbonate, wherein the foam molded product is constituted from, as a surface layer ranging from a surface of the foam molded product to a depth of 1000 μm, a surface layer consisting of only a foamed region in which a non-foamed portion having a cell density of 10% or less is not present, or the foam molded product has, as a surface layer ranging from a surface of the foam molded product to a depth of 1000 μm, a surface layer consisting of both a foamed region in which the non-foamed portion is present and a foamed region in which the non-foamed portion is not present, and wherein the foam molded product has a density of 0.01 to 0.70 g/cm3.