Modified Propylene Resin Adhesion Strength
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Solution Overview
Problem
The existing modified propylene resins used in composites with glass fibers suffer from reduced adhesion strength over time due to the presence of low-crystalline and low-molecular-weight components, which affects the durability and performance of the materials, especially under stress and high temperatures.
Innovation Solution
A modified propylene resin with specific properties is developed, including a melting point of 140°C or higher, 0.1-5% grafts of ethylenic unsaturated bond-containing monomer, 1.5% or less components soluble in o-dichlorobenzene at 70°C, intrinsic viscosity of 0.1-4 dl/g, and minimal chlorine content, achieved through blending propylene polymer with ethylenic unsaturated bond-containing monomer and organic peroxide in a solvent or molten state using a metallocene catalyst.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the amount of initiator (organic peroxide) is increased to improve the amount of grafts, then the adhesion strength between propylene resin and glass fibers is improved, but the molecular weight of the modified propylene resin is reduced
Solution Approach 1:
The patent changes the chemical parameters of the initiator system by using a specific combination of organic peroxides with different decomposition characteristics. This allows achieving high graft amounts while controlling the molecular weight reduction through parameter optimization rather than simple quantity increase.
Solution Approach 2:
The patent employs a composite initiator system consisting of multiple organic peroxides (e.g., dicumyl peroxide and 2,5-dimethyl-2,5-bis(t-butylperoxy)hexane) that work synergistically. This composite approach allows one peroxide to initiate grafting while another controls the degradation rate, resolving the contradiction between graft amount and molecular weight retention.
2Strength
If the amount of initiator (organic peroxide) is increased to improve the amount of grafts, then the adhesion strength between propylene resin and glass fibers is improved, but the durability of the composite is reduced
Solution Approach 1:
The patent optimizes the chemical parameters of the modification process by selecting specific organic peroxides with appropriate half-life periods at processing temperatures. This ensures sufficient grafting occurs while minimizing excessive chain scission that would create low-molecular-weight components harmful to long-term durability.
Solution Approach 2:
The patent creates an optimal balance point by referencing the relationship between initiator concentration, graft amount, and molecular weight. Through systematic experimentation, it identifies the specific parameter combination that achieves maximum adhesion strength while maintaining durability, effectively copying the ideal condition from extensive data analysis.
3Strength
If grafting is conducted to improve adhesion strength, then the adhesion between propylene resin and glass fibers is improved, but low-crystalline and low-molecular-weight components are generated
Solution Approach 1:
The patent converts the potentially harmful oxidation reaction during grafting into a beneficial process by carefully controlling the reaction conditions. The organic peroxide initiates both grafting and some oxidation, but by optimizing parameters, the beneficial grafting outweighs the harmful oxidation, and the resulting modified resin achieves superior adhesion without excessive low-molecular-weight byproducts.
Solution Approach 2:
The patent changes the physical and chemical parameters of the grafting process including temperature, time, and initiator type to minimize the formation of low-crystalline and low-molecular-weight components. By conducting grafting at controlled temperatures and using specific peroxide combinations, the reaction proceeds efficiently while limiting degradation products.
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 modified propylene resin enhances the durability and adhesion strength of propylene resin-glass fiber composites, maintaining performance over time and improving fatigue resistance, while also serving as a modifying agent for other polymer compositions, enhancing paintability, printability, and compatibility with other resins.
Implementation Method 1
blending propylene polymer with ethylenic unsaturated bond-containing monomer and organic peroxide in a solvent or molten state using a metallocene catalyst
Implementation Method 2
addition of a modified propylene resin produced by grafting an ethylenic unsaturated bond-containing carboxylic acid, e.g., maleic anhydride, on a propylene polymer in the presence of an initiator, e.g., an organic peroxide
Implementation Method 3
the adhesion strength between the propylene resin and the glass fibers is improved
Data Source
Figure 1~2E
AI summary
It is an object of the present invention to provide a modified propylene resin containing very small amounts of low-crystalline and low-molecular-weight components. The present invention relates to a modified propylene resin characterized by satisfying the following requirements (1) to (4). (1) The melting point (Tm) measured with a differential scanning calorimeter (DSC) is 140°C or higher. (2) The amount of grafts of ethylenic unsaturated bond-containing monomer after hot xylene washing is 0.1 to 5 percent by weight. (3) The amount of components soluble in o-dichlorobenzene at 70°C is 1.5 percent by weight or less. (4) The intrinsic viscosity [η] is 0.1 to 4 dl/g.