Matte Polyolefin Films with Low Heat Seal Initiation
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Solution Overview
Problem
Conventional matte polyolefin films lack heat sealing performance after corona treatment, particularly in the gusset area of flexible containers, due to a high heat seal initiation temperature.
Innovation Solution
A multilayer film structure comprising a matte layer with 20-80 weight % propylene-ethylene copolymer and 20-80 weight % ethylene-based polymer, combined with additional layers such as polyamide, propylene-based polymer, or ethylene-based polymers, which provides a gloss value of less than 10 units and a low heat seal initiation temperature of 70°C or below.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional matte polyolefin films are used, then a matte surface appearance is achieved, but heat sealing performance deteriorates due to high heat seal initiation temperature
Solution Approach 1:
The patent applies composite materials by creating a multilayer film structure where a matte layer (comprising propylene-ethylene copolymer and ethylene-based polymer) is combined with additional layers such as polyamide, propylene-based polymer, or ethylene-based polymers. This composite structure enables the film to simultaneously achieve matte surface appearance (gloss 45° value of less than 10 units) and low heat seal initiation temperature (70°C or below), resolving the contradiction between matte appearance and heat sealing performance
Solution Approach 2:
The patent applies parameter changes by carefully controlling the composition ratios (20 to 80 weight % propylene-ethylene copolymer and 20 to 80 weight % ethylene-based polymer), density ranges (0.857 to 0.895 g/cc for copolymer, 0.935 to 0.955 g/cc for ethylene-based polymer), and melt flow rates (I 2 of 2 to 25 g/10 min, I 5 of 0.1 to 1.0 g/10 min) of the polymers used in the matte layer. These parameter optimizations enable the film to achieve both the desired matte surface properties and improved heat seal initiation temperature of 70°C or below
2Illumination intensity
If conventional matte films are used, then a matte surface is achieved, but sealing performance after corona treatment deteriorates
Solution Approach 1:
The patent applies composite materials by designing a multilayer structure where the matte layer with specific polymer composition (propylene-ethylene copolymer and ethylene-based polymer in defined ratios) is combined with additional functional layers. This composite structure maintains matte surface appearance (gloss 45° value of less than 10 units) while significantly improving sealing performance after corona treatment, achieving heat seal strength of at least 4 N/25.4 mm at 100°C
Solution Approach 2:
The patent applies parameter changes by optimizing the polymer composition parameters including weight percentages (20 to 80% for each polymer), density ranges, and melt flow rates. These parameter optimizations ensure the film maintains matte appearance while achieving reliable sealing performance after corona treatment, with heat seal initiation temperature of 70°C or below and heat seal strength of at least 4 N/25.4 mm at 100°C
Data Source
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AI summary
Embodiments of the present disclosure are directed to multilayer films, which provide matte appearance and low heat seal initiation temperature after corona treatment. The multilayer films include at least one matte layer comprising ethylene-based polymer and propylene-ethylene copolymer.