Styrene Resin Composition for Deep Draw Carrier Tapes
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Solution Overview
Problem
Existing styrene resin sheets used for packaging electronic components face challenges in forming pockets with large draw ratios, resulting in reduced strength and transparency when thermoformed, making it difficult to observe writing on components through the packaging.
Innovation Solution
A sheet composition comprising 29 to 65 parts of styrene-conjugated diene block copolymer, 51 to 15 parts of polystyrene resin, and 20 to 9 parts of high-impact polystyrene resin, with specific weight-average molecular weights and melt tension properties, enabling the formation of pockets with excellent transparency and strength through thermoforming.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If general-purpose polystyrene resins are mixed with styrene-conjugated diene block copolymers to form transparent sheets, then transparency is improved, but when thermoformed into pockets with large draw ratios, the sheets become very thin at the cavities making it difficult to obtain sufficient strength
Solution Approach 1:
The patent applies parameter changes by precisely controlling the weight-average molecular weights of three different resin components: component (A) styrene-conjugated diene block copolymer (Mw=80,000 to 220,000), component (B) polystyrene resin (Mw=200,000 to 400,000), and component (C) high-impact polystyrene resin (Mw=150,000 to 210,000). This molecular weight optimization enables the resin composition to maintain both transparency and sufficient strength when thermoformed into pockets with large draw ratios, resolving the contradiction between transparency and strength.
Solution Approach 2:
The patent uses composite materials by formulating a resin composition containing three specific components: (A) styrene-conjugated diene block copolymer, (B) polystyrene resin, and (C) high-impact polystyrene resin, each with controlled molecular weights. This tri-component composite system combines the transparency benefits of polystyrene with the toughness of conjugated diene block copolymers and the impact resistance of high-impact polystyrene, achieving both transparency and strength simultaneously.
2Length of moving object
If pockets with large draw ratios are formed by thermoforming, then the depth of pockets is improved, but the sheets become less transparent than before forming
Solution Approach 1:
The patent applies parameter changes by optimizing the molecular weight parameters of the resin components to enable deep draw forming without sacrificing transparency. The specific molecular weight ranges allow the material to undergo significant deformation (large draw ratios) while maintaining optical clarity, thus achieving both deep pockets and high transparency.
3Length of moving object
If conventional resin compositions are used for deep draw forming, then pocket depth is improved, but buckling strength becomes insufficient
Solution Approach 1:
The patent uses composite materials with a tri-component resin system where component (A) styrene-conjugated diene block copolymer provides elasticity and formability for deep draw forming, while component (C) high-impact polystyrene resin contributes toughness and buckling strength. This composite structure enables simultaneous achievement of deep pockets and sufficient buckling strength.
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 sheet composition allows for the formation of carrier tapes with deep draw ratios that are both strong and transparent, enabling clear observation of writing on electronic components, while maintaining sufficient buckling strength and formativeness.
Implementation Method 1
when these sheets are thermoformed into carrier tapes or the like, if pockets with relatively large draw ratios are to be formed
Data Source
AI summary
An electronic component packaging sheet formed of a styrene resin composition includes: (A) 29-65 mass parts of a styrene-conjugated diene block copolymer; (B) 51-15 mass parts of a polystyrene resin; and (C) 20-9 mass parts of an impact resistant polystyrene resin. Components (A)-(C) each have a weight average molecular weight (Mw) within a specified range.