Block-Copolymer Pellets with Hydrocarbon Anti-Blocking Agents
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Solution Overview
Problem
Block copolymers with aromatic vinyl and conjugated diene polymer blocks face issues with dusting, blocking, and loss of transparency due to the use of anti-blocking agents, which affect their handling and adhesiveness.
Innovation Solution
A block-copolymer pellet comprising a block copolymer with specific properties and a hydrocarbon-based dusting agent within defined ranges of BET specific surface area, volume average particle size, bulk density, and melting point, along with controlled Shore A hardness and BET specific surface area, to enhance block resistance, transparency, and adhesiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an anti-blocking agent is attached to the surface of pellets to prevent blocking, then block resistance is improved, but transparency is lost and dusting occurs
Solution Approach 1:
The invention changes the parameters of the dusting agent from conventional materials to a hydrocarbon-based compound with specific properties (melting point 70-100°C, specific surface area 0.5-3.0 m²/g, particle size 2-20 μm). This parameter optimization allows the dusting agent to provide anti-blocking functionality while maintaining pellet transparency and reducing dusting, as the specific melting point range ensures it remains solid at storage temperatures but can be removed during processing
Solution Approach 2:
The invention creates a composite system by combining the block copolymer pellets with a specifically formulated hydrocarbon-based dusting agent. This composite approach allows the dusting agent to function as an anti-blocking agent without the negative effects of conventional agents, achieving both block resistance and transparency simultaneously through the synergistic combination of polymer and dusting agent properties
2Reliability
If an anti-blocking agent is used to prevent pellet blocking, then block resistance is improved, but dusting increases
Solution Approach 1:
The invention optimizes the particle size parameter of the dusting agent to 2-20 μm with a volume average within this range. This specific size control prevents excessive dusting while maintaining effective coverage for anti-blocking. The controlled particle size ensures the dusting agent is fine enough to provide uniform coverage but not so fine as to become excessive dust
Solution Approach 2:
The invention specifies the bulk density of the hydrocarbon-based dusting agent within 0.10-0.34 g/cm³. This density parameter optimization ensures the dusting agent has appropriate flowability and coating characteristics, allowing it to form an effective anti-blocking layer without creating excessive dust during handling and processing
3Ease of operation
If the block copolymer is pelletized for processing, then ease of operation is improved, but handling becomes difficult due to blocking
Solution Approach 1:
The hydrocarbon-based dusting agent provides self-service anti-blocking functionality through its specific melting point range (70-100°C). At storage temperatures below this range, the dusting agent remains solid and prevents pellet blocking automatically. During processing when temperatures exceed the melting point, the dusting agent softens and can be removed, allowing the pellets to be handled and processed normally without manual intervention for anti-blocking
Data Source
AI summary
A block-copolymer pellet having 100 parts by weight of a pellet-shaped article of a block copolymer (A) and 0.01 to 5 parts by weight of a hydrocarbon-based dusting agent (B) is provided, wherein the block copolymer (A) has at least one aromatic vinyl polymer block and at least one conjugated diene polymer block, the hydrocarbon-based dusting agent (B) has a BET specific surface area of 0.50 to 3.00 m2/g, a volume average particle size of 2.0 to 20 μm, a bulk density of 0.10 to 0.34 g/cm3, and a melting point of 75° C. or higher, and the block-copolymer pellet has a Shore A hardness of 10 to 80, and a BET specific surface area of 0.001 to 0.05 m2/g measured by a Kr adsorption method.