Tire Inner Liner Rubber Mixture for Airtightness and Fatigue
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Solution Overview
Problem
Pneumatic vehicle tires face challenges in achieving improved airtightness and fatigue resistance due to the trade-offs between crack resistance, heat build-up, abrasion resistance, and air permeability in the rubber mixtures used for inner components, particularly the inner liner and sidewalls.
Innovation Solution
The use of a rubber mixture with a specific composition for multiple inner components, including 10-60 phr natural or synthetic polyisoprene, 20-60 phr polybutadiene rubber, 0-60 phr styrene butadiene rubber, 0-30 phr halobutyl rubber, 40-100 phr carbon black with specific surface characteristics, and 5-80 phr delaminated talc or kaolinite, which simplifies tire construction and reduces material costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If halobutyl rubber is used to improve airtightness, then air permeability is reduced, but crack resistance and fatigue properties deteriorate
Solution Approach 1:
The patent uses a composite rubber mixture containing multiple rubber types (natural rubber, synthetic polyisoprene, polybutadiene rubber, styrene butadiene rubber, and halobutyl rubber) in specific proportions. This composite approach combines the low gas permeability of halobutyl rubber with the good crack resistance of natural rubber and polybutadiene rubber, achieving both airtightness and fatigue resistance simultaneously.
2Reliability
If voluminous fillers with little or no activity are added to increase airtightness, then air permeability is reduced, but crack and fatigue properties are impaired
Solution Approach 1:
The patent combines active fillers (carbon black with specific surface area and DBP number ranges, silane-modified polysiloxane) with voluminous fillers (delaminated talc and/or kaolinite). The active fillers provide reinforcement and improve crack resistance, while the voluminous fillers contribute to airtightness. This composite filler system resolves the contradiction between airtightness and fatigue resistance.
3Reliability
If the rubber composition of inner components is optimized for one property, then that property is improved, but other properties deteriorate
Solution Approach 1:
The patent carefully controls the proportion of halobutyl rubber (0-30 phr) and the specific surface area of carbon black (10-100 m²/g) to balance airtightness and heat build-up. By adjusting these parameters within optimal ranges and using a multi-component rubber system, the patent achieves good airtightness while preventing excessive heat generation that would occur with high halobutyl rubber content alone.
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
This approach enhances airtightness, fatigue resistance, and crack resistance while maintaining suitable adhesion, leading to improved driving performance and reduced manufacturing complexity and costs.
Implementation Method 1
The airtightness can be further increased by metering in voluminous fillers with little or no activity and/or fillers with a layered or platelet structure
Implementation Method 2
The rubbers used for the inner liner are usually chlorobutyl rubber or bromobutyl rubber, occasionally in a blend with natural rubber. These types of rubber have low gas permeability.
Implementation Method 3
40 to 100 phr of at least one carbon black having an STSA surface according to ASTM-D 6556 from 10 to 100 m 2 /g and a DBP number according to ASTM-D 2414 from 50 to 160 mL/100 g
Data Source
AI summary
The invention relates to a rubber mixture, in particular for pneumatic vehicle tires, seatbelts, belts and hoses, and a pneumatic vehicle tire, wherein at least two inner components of the pneumatic vehicle tire are made of such a rubber mixture which is identical with regard to quality and quantity. The rubber mixture has the following composition: 10 to 60 phr of at least one natural or synthetic polyisoprene, 20 to 60 phr of at least one polybutadiene rubber, 0 to 60 phr of at least one styrene butadiene rubber, 0 to 30 phr of at least one halobutyl rubber, 40 to 100 phr of at least one carbon black with an STSA surface as defined according to ASTM-D 6556 of from 10 to 100 m2/g and a DBP number defined according to ASTM-D 2414 of from 50 to 160 mL/100g, 5 to 80 phr of at least one delaminated talcum and/or kaolinite, and - other additives.