Rubber Composition Bale Formulation for Cold-Flow and Heat Stability
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Solution Overview
Problem
Conventional rubber compositions for tire treads with an ethylene structure and crosslinkable unsaturated groups face issues such as cold flow, thermal deterioration, mold contamination, and difficulty in adhering packaging sheets to molded bales.
Innovation Solution
A molded bale of a rubber composition with a specific range of aluminum content, incorporating a rubber-like polymer with an iodine value of 10 to 250 and less than 10% vinyl aromatic monomer block, along with other specified components, which inhibits cold flow and thermal deterioration during production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a rubber composition containing a rubber-like polymer with an ethylene structure and a crosslinkable unsaturated group is used to increase mechanical strength, then the mechanical strength is improved, but the molded article easily undergoes cold flow and changes shape
Solution Approach 1:
The invention changes the chemical composition parameters by introducing aluminum in a specific amount (2-200 ppm) and controlling the vinyl aromatic monomer block content (less than 10% by mass). These parameter changes modify the rubber composition's properties to prevent cold flow while maintaining mechanical strength.
2Strength
If a rubber composition containing a rubber-like polymer with an ethylene structure and a crosslinkable unsaturated group is used to increase mechanical strength, then the mechanical strength is improved, but the rubber composition is thermally deteriorated during production
Solution Approach 1:
The invention modifies the thermal stability by adjusting the aluminum content to 2-200 ppm and controlling the vinyl aromatic monomer block content. These parameter changes create a more thermally stable rubber composition that resists deterioration during production processes.
3Strength
If a rubber composition containing a rubber-like polymer with an ethylene structure and a crosslinkable unsaturated group is used, then the mechanical strength is improved, but the used mold is easily contaminated
Solution Approach 1:
The invention reduces mold contamination by optimizing the aluminum content to 2-200 ppm and limiting the vinyl aromatic monomer block content to less than 10% by mass. These compositional changes reduce the tendency of the rubber to adhere to and contaminate mold surfaces.
4Strength
If a rubber composition containing a rubber-like polymer with an ethylene structure and a crosslinkable unsaturated group is used, then the mechanical strength is improved, but the rubber composition is easily peeled off from a molded bale
Solution Approach 1:
The invention improves adhesion stability by controlling the aluminum content within 2-200 ppm and limiting the vinyl aromatic monomer block content to less than 10% by mass. These parameter adjustments enhance the cohesive properties of the rubber composition, preventing peeling from the molded bale.
5Strength
If a rubber composition containing a rubber-like polymer with an ethylene structure and a crosslinkable unsaturated group is used, then the mechanical strength is improved, but a packaging sheet is difficult to adhere to the molded bale
Solution Approach 1:
The invention facilitates packaging sheet adhesion by optimizing the aluminum content to 2-200 ppm and controlling the vinyl aromatic monomer block content to less than 10% by mass. These compositional modifications improve the surface properties and adhesion characteristics of the molded bale.
Data Source
AI summary
An object of the present invention is to obtain a molded bale of a rubber composition that is difficult to cold flow and difficult to be thermally deteriorated. The present invention provides a molded bale of a rubber composition containing: a rubber-like polymer (A) having an iodine value of 10 to 250, 3% by mass or more of an ethylene structure, and less than 10% by mass of a vinyl aromatic monomer block; and aluminum (B), in which a content of the aluminum (B) is 2 ppm or more and 200 ppm or less.