Co-vulcanizing Colored Labels on Tire Sidewalls
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Solution Overview
Problem
The application of adhesive labels on vulcanized tires faces challenges such as poor adhesion due to cyclical deformation and temperature changes, leading to scratches and aesthetic issues, and requires complex production steps that decrease productivity and increase costs.
Innovation Solution
Applying labels made of colored cross-linkable elastomeric material on the vulcanization mold during the vulcanization process, ensuring co-vulcanization with the tire and precise positioning to maintain shape and resist abrasion, using a support film and bi-adhesive film for secure attachment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If adhesive labels are applied on vulcanized tyres, then decorative elements can be added to the sidewall, but adhesion is poor due to cyclical deformation and temperature changes leading to scratches and detachment
Solution Approach 1:
The label is applied to the green tyre (uncured) before vulcanization, allowing the label and tyre to be bonded simultaneously during the vulcanization process. This preliminary action ensures the label becomes an integral part of the tyre structure, preventing later detachment due to deformation and temperature changes.
Solution Approach 2:
The labeling process is merged with the vulcanization process by applying the label to the green tyre and performing both operations together in a single step. The label and tyre are co-vulcanized, creating a unified structure where the label cannot detach independently.
2Reliability
If labels are applied on green tyres before vulcanization, then adhesion is improved, but the label positioning precision and shape maintenance deteriorate
Solution Approach 1:
The vulcanization process parameters (temperature, pressure, time) are controlled to ensure the label maintains its shape and position while bonding to the tyre. The gradual heating and controlled curing allow the label to set in the correct position without distortion.
Solution Approach 2:
A support film is used as an intermediary carrier for the label during application and vulcanization. This support film helps maintain label positioning precision and shape, then is removed after vulcanization to reveal the properly positioned label on the tyre.
3Manufacturing precision
If labels are applied after vulcanization, then positioning is easier, but additional production steps are required decreasing productivity and increasing costs
Solution Approach 1:
The labeling operation is combined with the vulcanization operation into a single integrated process step. By applying the label to the green tyre and vulcanizing together, no separate post-vulcanization labeling step is needed, maintaining productivity while achieving precise positioning through the support film method.
4Ease of manufacture
If complex post-vulcanization labeling steps are added, then label application is possible, but production costs and complexity increase
Solution Approach 1:
The label is prepared with adhesive and support film in advance, allowing it to be applied to the green tyre before vulcanization. This preliminary preparation enables labeling to be integrated into the existing vulcanization process without adding complex post-vulcanization equipment or steps.
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 solution ensures labels are accurately positioned and securely attached to the tire without aesthetic defects or detachment, eliminating post-vulcanization complications and enhancing production efficiency.
Implementation Method 1
both faces of said bi-adhesive film, wherein said layer of colored cross-linkable elastomeric material is arranged on one face of said bi-adhesive film
Implementation Method 2
co-vulcanization of the green tyre and of the layer of polymeric material
Data Source
Figure 1
Figure 2~2a
Figure 3
AI summary
In the production of tyres for vehicle wheels in which at least one colored label (200) is provided on at least one of the sidewalls of the tyre, a green tyre is arranged inside a vulcanization mold comprising a first half-shell (50), a second half-shell opposite to the first half-shell (50) and a crown of circumferential sectors configured to air-tightly couple with the first half-shell (50) and with the second half-shell when the vulcanization mold is closed. Each label (200) comprises a layer of colored cross-linkable elastomeric material. Each label (200) is arranged in a predetermined position on a first support surface (50a) defined in at least one of the aforementioned first and second half-shell. The green tyre is arranged inside the vulcanization mold so that one of the sidewalls of the green tyre rests on such a support surface (50a). The mold is then closed and the co-vulcanization of the green tyre and of the label(s) (200) inside the vulcanization mold starts, holding in position the labels (200) on the first support surface (50a) during at least one initial part of the vulcanization.