Crystal International Group Limited has been spearheading advancements in textile technology. The Group has collaborated with the Hong Kong Productivity Council (“HKPC”) – a leading international research institute that brings nearly 20 years of extensive expertise in nanomaterial development and industrial application – on a groundbreaking project, which also secured funding from the Innovation and Technology Commission, to advance the field of thermal clothing by applying innovative graphene electrothermal technology – reduced graphene oxide (“r-GO”). Leveraging HKPC’s comprehensive innovative solutions, the project optimises the r-GO composite coating, tuning electrical conductivity for maximum heat output. A precision smart-screen-printing system then integrates the additive seamlessly into garments, boosting electrothermal efficiency while cutting production costs. The result is a new generation of thermal clothing that elevates Hong Kong industry competitiveness at home and abroad—delivering higher productivity, lower resource consumption, and sharper market differentiation.
Commencing in 2021, the project has progressed through two significant phases of development and implementation. During the first phase, the knits division of Crystal International participated as the Industry Co-Applicant, sponsoring essential funding and providing technical contribution for the research and development of multifunctional fabrics with graphene coating for smart wearable applications, in partnership with HKPC and The Hong Kong Research Institute of Textiles and Apparel (“HKRITA”). Integrated with power devices and voltage supply, the cutting-edge technology r-GO, as an electrothermal material, enables the functional properties of thermal clothing. With the technology authorisation from HKPC, Crystal International successfully obtained the utility model patent in China upon completing the development.
In 2023, the project transitioned into the Public Sector Trial Scheme led by HKPC as the second phase, focusing on applying this groundbreaking technology to finished garment production. This phase involved fabricating prototypes and electrothermal clothing samples, as well as conducting wearer trials in public elderly care homes including Tung Wah Group of Hospitals’ Wong Cho Tong Day Care Centre for the Elderly, which demonstrated the practical application of electrothermal clothing for enhancing comfort and warmth for elderly residents. The thermal clothing has passed laboratory tests on rubbing and washing durability, electrical safety, and skin irritation. The innovative r-GO fabric boosts heating efficiency compared to traditional electrothermal fabric.
The field trials engaged 100 elderly users, who provided insights through user feedback surveys on warmth, heating uniformity, ease of usage, and durability. The garments reached a heating rate of 30°C within 2 minutes, demonstrating rapid thermal response for user comfort. With superior functional and electrothermal performances of the vests, the users expressed high level of overall satisfaction, scoring 8.3 out of 9 in average.
“We are thrilled to be at the forefront of this project that not only showcases our excellence to innovation but also addresses the needs of flexible electrothermal fabric in the industry. By leveraging advanced technology in textiles, we aim to improve the quality of life for the groups who are in need while promoting sustainable fashion practices,” said Danny Cheng, General Manager – Technical Service and Support at Crystal International.
In addition to clothing, the flexible r-GO composite fabric is applicable on other usages such as heating shoes insoles and heat therapy bandages, benefiting broader communities. The Group is trying to explore commercialisation opportunities for the innovative r-GO clothing. In response to the emerging technologies in textiles, Crystal International strives to gear up with industry stakeholders to pioneer fashion innovation.
