Resin power? Shiseido files patent on metal-free makeup tools

Writing in its international patent​,​ Shiseido said the resin makeup tools offered an alternative to traditional metal products – problematic for consumers with metal allergies and skin sensitivity issues. Importantly, it said the designs, particularly the eyelash curler, maintained the traditional shapes, sizes and mechanisms consumers were accustomed to.

“The eyelash curler of the present embodiment has a configuration similar to a general metal eyelash curler, and is integrally formed of a resin,”​ Shiseido wrote in its patent.

Pure resin eyelash curlers, tweezers and beauty scissors​

Whilst part-resin, part-metal eyelash curlers had already been developed, Shiseido said the manufacturing and assembly process was complicated and tough to scale-up efficiently. The mixed metal-resin eyelash curlers also tended to be much larger than traditional metal formats and required different operating methods.

There therefore remained a need to develop metal-free alternative makeup tools, Shiseido said.

“The present invention aims to provide a resin makeup tool that can secure the strength and can be operated in the same manner as a metal [tool], without increasing the size of a general metal shape.”​

Shiseido’s patent covered eyelash curlers, tweezers, beauty scissors, razors and nail clippers – all made entirely of reinforced resin.

Matching metal strength with glass and carbon fibres ​

Following experiments among a small pool of test subjects to ascertain average clamp pressure needed with metal eyelash curlers, Shiseido worked on computer prediction models to understand the design and materials needed to support this action pressure when using resin instead.

The personal care major said that to enable the shape, size and design consumers were already familiar with, resin had to be mixed with glass or carbon fibre: fibre-reinforced resin.

“By adding glass fibre or carbon fibre, the rigidity can be strengthened against the deformation and breakage of the resin material itself,”​ it said. “…Therefore, it is possible to obtain a pressure close to that of metal between the eyelashes.”​

A range of resins could be used in the design, Shiseido said, “as long as the resin can be mixed with the fibre”.​

Resins including polyamide, polyphenylene sulphide or polyether ether ketone were all suitable options. Shiseido said the resin blend had to incorporate 30% or more mass resin and 65% or less glass fibre.

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WIPO International Patent No. WO/2020/059714​​
Published on: March 26, 2020. Filed on: September 17, 2019.
Title: “Makeup tool and eyelash curler”​
Inventor: Shiseido Company – S. Ogata, T. Fujioka and M. Nagoshi