YOKOHAMA's Technology
Development of significantly lighter weight automotive AC hoses using proprietary rubber-resin polymer alloy technologyResponding to the needs of next-generation environment-friendly vehicles
MB
The automotive industry is undergoing a once-in-a-hundred years dynamic transformation. One of the most impactful changes is the transformation of vehicles’ powertrain. With next-generation environment-friendly vehicles, such as electric vehicles (EVs), coming into greater use around the world as countries aim to achieve carbon neutrality by 2050, reducing vehicle weight has become an important factor for extending driving range and improving fuel efficiency. Accordingly, the need for lighter automotive parts also is increasing.
In addition to being a major tire maker, Yokohama Rubber supplies automakers with various automotive parts. Our Hose & Couplings business, which is based on our strong polymer materials technology, supplies air-conditioning (AC) hoses to many automakers. To meet automakers’ increasing demand for lighter-weight parts, the business is now making hoses that use resin material as well as conventional rubber.
Use of resin as a hose material has achieved a 50% weight reduction compared to conventional hoses
Conventional automotive AC hoses have two layers of thick rubber to ensure gas barrier properties needed to prevent refrigerant gas permeation . This thick rubber increases the weight of the hose.
Responding to the need for lighter hoses, Yokohama Rubber has applied its proprietary material technology to the development of a rubber-resin polymer alloy that achieves a structure with an optimal arrangement of rubber and resin. Polymer alloys are blends of different polymers that result in a material with new properties. Yokohama Rubber’s rubber-resin polymer alloy has a sea-island structure in which “rubber islands” are dispersed in a “sea of resin.”
Hoses using this sea-island structure achieve the high gas barrier properties of resin while maintaining the flexibility and heat resistance of rubber. In addition, the use of a rubber-resin polymer alloy has reduced hose thickness and achieved a significant weight reduction of 50% compared to conventional hoses. The manufacturing process for this new rubber-resin polymer alloy eliminates the need for vulcanization, which requires a large amount of heat, thus reducing CO2 emissions during manufacturing.
Aiming to achieve pipe resinification
Having developed lighter hoses using its rubber-resin polymer alloy, Yokohama Rubber is now using its resin technologies to reduce the weight of hosing pipes , which to date have been made of metal. We have succeeded in establishing manufacturing methods for all pipes used in automotive AC systems, including high-pressure, low-pressure, and liquid pipes . The new methods have fewer processes and lower quality risks than previously used methods. We also are promoting the recycling of used raw materials.
Yokohama Rubber is positioning its rubber-resin polymer alloy hoses and resin piping as one of the new products that will drive the growth of its Hose & Couplings business. We plan to expand their application to battery-cooling hoses, for which we expect strong demand from EV makers similar to their demand for lighter AC hoses.
