Block Copolymer Tire Sealing Layer Adhesion and Rolling Resistance
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Solution Overview
Problem
Current waterproof layers in tires based on butyl rubber exhibit significant hysteretic losses, leading to increased rolling resistance, and struggle with adhesion to adjacent diene layers, necessitating improved adhesion and sealing properties.
Innovation Solution
A tire comprising a block copolymer with a thermoplastic block derived from styrenic monomers and an elastomeric block as a random copolymer of isobutylene and haloalkylstyrene monomers, used in a waterproof layer to enhance adhesion and sealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If sealing layers are made from butyl rubber to achieve good adhesion to diene layers, then adhesion is improved, but hysteresis losses increase leading to higher rolling resistance
Solution Approach 1:
The patent employs a composite elastomeric composition combining polybutadiene (providing low hysteresis and low rolling resistance) with a small amount of butyl rubber (providing adhesion to diene layers). This composite approach allows the sealing layer to simultaneously achieve low energy losses and reliable adhesion, resolving the contradiction between these two properties.
2Use of energy by moving object
If sealing layers are made from thermoplastic block elastomers to reduce rolling resistance, then hysteresis losses are reduced, but adhesion to adjacent diene layers deteriorates
Solution Approach 1:
The patent creates a composite elastomeric composition where polybutadiene (low hysteresis) is combined with butyl rubber (good adhesion). This composite allows the material to exhibit both low rolling resistance and strong adhesion to diene layers, overcoming the limitation of pure thermoplastic block elastomers.
Solution Approach 2:
The patent carefully controls the composition parameters, specifically limiting butyl rubber content to 1-20 phr (parts per hundred rubber) and polybutadiene to 80-99 phr. By optimizing these compositional parameters, the material achieves the right balance between adhesion and low hysteresis properties.
3Reliability
If sealing layers are made from butyl rubber to ensure good sealing properties, then airtightness is improved, but rolling resistance increases due to hysteresis losses
Solution Approach 1:
The patent uses a composite elastomeric composition where polybutadiene provides low hysteresis (reducing rolling resistance) while butyl rubber contributes to sealing performance. The synergistic combination allows the sealing layer to maintain effective sealing against inflation gases while minimizing energy losses.
Data Source
AI summary
The invention relates to a pneumatic tyre comprising a block copolymer comprising at least one thermoplastic block comprising units from at least one styrene monomer and at least one elastomer block in the form of a statistical copolymer comprising units from isobutylene and units from at least one halogenoalkyl styrene monomer. The invention also relates to the use of said block copolymer in a tight layer of a pneumatic tyre. The invention further relates to a pneumatic tyre provided with a tight layer based on an elastomer composition comprising an elastomer matrix comprising at least 50 pce of said block copolymer.