Laminating Resin Composition for Polypropylene Tear Strength
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Solution Overview
Problem
Conventional laminating resin compositions for polypropylene, while improving productivity, often result in decreased adhesion to substrates, tear strength, and deterioration of optical and surface properties.
Innovation Solution
A laminating resin composition comprising a polyolefin resin, specifically a random copolymer of propylene and an α-olefin, combined with a polyethylene wax of controlled density and molecular weight, which maintains the optical and surface properties of polypropylene while enhancing tear strength and productivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional forming auxiliaries (oils and polyethylene waxes) are blended with thermoplastic resins to improve productivity, then productivity in the lamination process is improved, but adhesion to substrates and tear strength are lowered
Solution Approach 1:
The patent applies parameter changes by precisely controlling the molecular weight (Mw) of the polyethylene wax within 1,000 to 10,000 g/mol and its content within 0.1 to 10 parts by weight per 100 parts of polyolefin resin. This optimized parameter range allows the wax to function as an effective forming auxiliary that improves productivity while maintaining adequate tear strength and adhesion, resolving the contradiction between productivity improvement and strength maintenance.
2Productivity
If conventional forming auxiliaries are added to improve productivity, then productivity is improved, but optical characteristics and surface properties are deteriorated
Solution Approach 1:
The patent uses parameter changes by selecting a polyethylene wax with specific molecular weight (Mw: 1,000 to 10,000 g/mol) and controlling its content (0.1 to 10 parts by weight per 100 parts of polyolefin resin). These controlled parameters ensure the wax improves productivity through enhanced forming properties while minimizing negative impacts on optical characteristics and surface properties, as the wax content and molecular weight are optimized to prevent excessive light scattering or surface defects.
3Strength
If polyethylene wax with high molecular weight is used to maintain strength, then tear strength is maintained, but productivity in lamination process is reduced
Solution Approach 1:
The patent resolves this contradiction through parameter changes by optimizing the molecular weight (Mw) of the polyethylene wax to fall within 1,000 to 10,000 g/mol. This specific molecular weight range ensures the wax provides sufficient forming assistance to improve productivity while maintaining adequate tear strength. The optimized parameter balance allows the wax to function effectively as a forming auxiliary without excessive molecular weight that would compromise productivity or strength.
Data Source
AI summary
Laminating resin compositions of the invention enable excellent productivity in the lamination processes, and are free from deterioration in optical characteristics such as transparency or surface properties inherent to resins such as polypropylenes. Multilayer structures obtained by laminating the composition on a substrate have tear strength which is as high as that of multilayer structures obtained by simply laminating a polyolefin resin such as polypropylene on a substrate. The laminating resin composition includes a polyolefin resin and a polyethylene wax having a density in the range of 890 to 955 kg/m3 as measured by a density gradient tube method in accordance with JIS K 7112 and a number average molecular weight (Mn) in terms of polyethylene in the range of 500 to 2900 as measured by gel permeation chromatography (GPC).