Elastomer Resin Composition Suppressing Neck-In in Film Extrusion
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Solution Overview
Problem
Existing resin compositions face issues with neck-in during extrusion molding, poor adhesiveness to both polar and apolar materials, and require additional steps like coating, drying, and curing, leading to increased costs and environmental concerns.
Innovation Solution
An elastomer resin composition is developed by adding a polypropylene polymer with an elongation viscosity ratio of 5.0 or more to a thermoplastic elastomer, which suppresses neck-in and enhances adhesiveness, allowing for a pressure-sensitive adhesive film that can adhere to various materials without additional adhesives.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a thermoplastic elastomer is molded by film-like extrusion, then the resin composition can be processed into a film, but the molded product is broken and undergoes severe neck-in due to poor melt tension
Solution Approach 1:
The patent uses a composite resin composition consisting of a thermoplastic elastomer (block copolymer of aromatic vinyl compound and conjugated diene compound) combined with a specific polypropylene polymer having high elongation viscosity ratio. This composite structure combines the adhesive properties of the elastomer with the melt strength improvement from the polypropylene, resolving the neck-in issue while maintaining film extrusion capability
Solution Approach 2:
The patent specifies precise parameter ranges for the polypropylene polymer component, particularly the elongation viscosity ratio η2.5/η1.0 ≥ 5.0 and molecular weight distribution. By controlling these parameters, the resin composition achieves adequate melt tension during extrusion while maintaining good adhesiveness, thereby preventing neck-in and product breakage
2Adaptability or versatility
If decorative film and adherend have different polarity materials, then material selection is flexible, but the film cannot adhere to the adherend without additional adhesive
Solution Approach 1:
The thermoplastic elastomer component in the resin composition provides universal adhesive properties that work with both polar and apolar materials. The block copolymer structure with aromatic vinyl compound blocks and conjugated diene compound blocks creates surfaces that can bond to diverse substrates, eliminating the need for separate adhesive applications and enabling direct adhesion of decorative films to various adherends
3Reliability
If separate adhesive is applied to achieve adhesion between different polarity materials, then adhesion is achieved, but additional coating, drying, and curing steps are required increasing time and cost
Solution Approach 1:
The patent merges the adhesive function into the film material itself by incorporating the thermoplastic elastomer in the resin composition. This eliminates the separate adhesive layer and its associated coating, drying, and curing steps. The adhesive properties are now an inherent characteristic of the film, allowing direct bonding to both polar and apolar adherends in a single processing step, thereby significantly reducing production time and complexity
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 solution results in a pressure-sensitive adhesive film with improved extrudability, reduced neck-in, and excellent adhesiveness to both polar and apolar materials, eliminating the need for separate adhesives and reducing production time and environmental impact.
Implementation Method 1
a polypropylene polymer (B), which has the elongation viscosity ratio η2.5/η1.0 being 5.0 or more, where each of η1.0, and η2.5 represents the elongation viscosity at a strain of 1.0 and 2.5, respectively
Implementation Method 2
a thermoplastic elastomer (A), which is a block copolymer having a polymer block (a1) containing a structural unit derived from an aromatic vinyl compound and a polymer block (a2) containing a structural unit derived from a conjugated diene compound
Data Source
AI summary
Provided are: an elastomer resin composition excellent in extrudability and having good adhesiveness to polar materials and apolar materials; a pressure-sensitive adhesive film using the elastomer resin composition and excellent in shape retention, and a method for producing it; a film having the pressure-sensitive adhesive film; and a molded article having the film. The elastomer resin composition contains a thermoplastic elastomer (A) of a block copolymer having a polymer block (a1) that contains a structural unit derived from an aromatic vinyl compound and a polymer block (a2) that contains a structural unit derived from a conjugated diene compound, or a hydrogenate of the block copolymer, and a polypropylene polymer (B) such that, when the elongation viscosity thereof, as measured at a strain of 1.0 and 2.5 in uniaxial elongation viscosity measurement under the condition of a strain rate of 1.0 sec-1 and a measurement temperature of 180°C, is represented by η1.0, and η2.5, respectively, the elongation viscosity ratio η2.5/η1.0 is 5.0 or more, wherein the content of the polypropylene polymer (B) is 5 to 15 parts by mass relative to 100 parts by mass of the thermoplastic elastomer (A).