Acid-Modified Polypropylene Resin Adhesive Strength
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Solution Overview
Problem
Polypropylene resins have poor adhesive properties with polar resins due to their low polarity, and existing methods to improve their chemical reactivity, such as grafting organic acids, often result in decreased molecular weight and impaired physical properties.
Innovation Solution
An acid-modified polypropylene resin is developed with a specific range of organic acid component grafting (1.0 to 20.0 wt%) and melt flow rate (Y ≤ 18.5 exp(0.82 X), ensuring high grafted amounts and molecular weights, achieved by using an organic peroxide with a bivalent connecting group like -O-CO-O-O-, to enhance adhesive properties with both polyolefin and polar resins.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the grafted amount of organic acid component is increased to improve adhesive properties, then the adhesive strength is improved, but the molecular weight decreases resulting in impaired physical properties
Solution Approach 1:
The patent applies parameter changes by carefully controlling the grafted amount of organic acid component within a specific range (1.0 to 20.0 wt%) and maintaining the melt flow rate within specific ranges (0.1 to 100 g/10min at 230°C, or 1 to 50 g/10min at 230°C). This optimization of parameters allows achieving high adhesive strength while preserving sufficient molecular weight and physical properties.
2Adaptability or versatility
If the grafted amount of organic acid component is increased to improve adhesive properties, then the polarity is improved, but the impact resistance decreases
Solution Approach 1:
The patent resolves this contradiction by optimizing the grafted amount parameter within 1.0 to 20.0 wt% and controlling the melt flow rate parameter within specific ranges. This balanced parameter optimization ensures sufficient polarity improvement for adhesive properties while maintaining adequate molecular weight for impact resistance.
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 acid-modified polypropylene resin exhibits excellent adhesive properties, compatibility, and regrind characteristics, enabling strong bonding between polyolefin and polar resins, maintaining high molecular weight and physical properties, suitable for various applications including laminated films and food packaging.
Implementation Method 1
a method of grafting, to a polypropylene resin, an unsaturated carboxylic acid or its anhydride, represented by e.g. maleic anhydride, to modify the polypropylene resin, has been known. Such an acid-modified polypropylene resin is produced by graft reaction of an organic acid component, using, as an initiator, radicals generated by an organic peroxide, heat decomposition or the like.
Data Source
Figure 1
AI summary
To provide an acid-modified polypropylene resin which can be used for an adhesive capable of bonding a polyolefin type resin and a polar resin with sufficient force, its production process and a resin composition using it. An acid-modified polypropylene resin, which is obtained by grafting an organic acid component to a polypropylene resin, wherein the polypropylene resin is an isotactic polypropylene resin, the grafted amount X (wt%) of the organic acid component in the acid-modified polypropylene resin is within a range of from 1.0 wt% to 20.0 wt%, and the melt flow rate Y (g/10 min) of the acid-modified polypropylene resin satisfies the expression: Y≦18.5exp(0.82X), a process for producing such an acid-modified polypropylene resin, a resin composition using it and a laminate.