HOYU's graphene laminated fabric was awarded by ISPO Textrends 2020/21 with UC's graphene hydrophilic membrane

- Why we utilize UC’s graphene waterproof and breathable membrane - UniTran™: GM series?

With the great thermal conductivity and heat radiation ability of graphene, the graphene added waterproof and breathable membrane could have a strong heat dissipation function with heat conducting and radiative behavior. However, their unique sheet morphology and surface nature leads a strong agglomeration and poor dispersion in polymer matrix. This poor dispersion will not only result in a lower heat dissipation below the expectation, also weaken the strength of the polymer matrix, and moreover, the agglomerated graphene may reduce the moisture permeability of the membrane.

UC applied our own high concentrated graphene suspension as the core material into hydrophilic PU resin to develop graphene added waterproof and breathable membrane. With a proper dispersion, recipe design and rheology control, we finally find a way the control the dispersion and alignment of graphene in polymer matrix. At the same time, our unique dispersion process and surface modification will adjust the affinity between graphene and polymer matrix and leads a homogeneous dispersion on the particle size and layer thickness and higher stacking density of graphene, and finally enhance the heat dissipation of waterproof and breathable membrane.

- What is the advantages for graphene Waterproof and breathable membrane to modern apparel industry ?

Waterproof and breathable membrane is a vital part of the modern apparel industry, the major application are outdoor apparel (including mountaineering suit or winter jacket), protective suit, or military wears. In general, the function and specification of waterproof and breathable membrane will be defined by water vapor resistance and moisture permeability by certain certification of ASTM, ISO or JIS standards. The specification of waterproof and breathable membrane could be determined as highly water resistant with high breathability, highly water resistant with low breathability, or lower water resistant with high breathability. In the other hand, waterproof and breathable membrane also could be determined by their materials, forming process and their microstructure. Three common waterproof and breathable membrane in modern apparel industry are ePTFE membrane with microporous structure, PU hydrophobic membrane with microporous structure, and non-porous PU hydrophilic membrane. In recent, some new type of waterproof and breathable membrane applied by the bio/recycled materials or modified elastic polyester materials had been proposed due to the eco-friendly issues.

Adding graphene into waterproof and breathable membrane is an innovative application recently. In general, the mechanism for waterproof and breathable membrane is that the moisture, sweat or vapor could be penetrated through the membrane and prevent the water drop to get inside the membrane. But normally the wearer usually feel discomfort after a intense exercise when wearing the apparel with waterproof and breathable membrane. It is because the moisture will be accumulated at the interface between skin and membrane, and further cause the heat accumulation and also discomfort while wearing. Therefore, using a thermal conductive graphene to develop a whole new “graphene waterproof and breathable membrane” with water vapor resistance, moisture permeability and heat dissipation will be the possible solution for the above problem. The continuous stacked graphene inside the waterproof and breathable membrane would generate a heat conducting path for the heat transfer, and further improve the discomfort. In the meantime, the high stiffness and self-lubricity of graphene also could change the strength, stiffness and hand feeling of membrane.

HOYU utilized UC’s graphene waterproof and breathable membrane to develop the innovated lamination fabric. Using the thermal dissipation module followed by ASTM D1518 under the practical environment, we found this graphene lamination fabric could have more than 20% enhancement on the heat dissipation, and a obvious reduction of 0.27 on clo value would represent an temperature decrease of 1.5℃ after 30mins. It means the graphene would improve the heat conduction of the membrane and transfer the heat from the body to environment continuously and achieve the goal for the long-last cooling. At the same time, the unique touch also dramatically changes on the hand feeling of graphene lamination fabric and open more opportunity for outdoor apparel innovation.