Coatings World - MAY 2017

Thomas W. Schmidt and Xing-Sheng Jiang, Huafeng, Huangshi Ind. Dev. Zone, Putian, China; Li Chuan Lillian Tseng, Graduate Institute of Management, National Taiwan University of Science and Technology, Taipei, Taiwan

Abstract

A new and selective additive 3D coating technology was developed and implemented for mass production. Besides attractive visual design opportunities, a strong focus is on the touch experience of final products. Haptic perceptions can be controlled by application of selective multi‐layer 3D textures, by the shape and thickness of these 3D textures, and by the coating formulation itself. The coating formulation can be fine‐tuned to achieve soft‐touch nubuck‐like effects, as well as smooth, slippery, sticky effects or rough sandpaper-like effects. In combination with attractive colors such as metallics, color shifting or thermochromic colors and finishes with controlled matte or glossy surfaces, a huge freedom of design is allowed.

Today, haptic coatings are applied on textile substrates for the sporting goods industry. The haptic coatings are very robust and only use safe and environmentally friendly chemistry. They fulfill all mechanical requirements for application on sneakers and sports apparel. In addition, full compliance to the strict-est restricted substances list (RSL) and manufacturing restricted substances list (MRSL) can be achieved.

With the selective additive coating ap-
proach, highest material efficiency can be
achieved. This revolutionary approach
to sneaker manufacturing improves the
sustainability and the environmental
footprint of the supply chain for sports
footwear and garments. Cutting waste
does not exist and material is only ap-
plied where it is needed. Huafeng, as a
T2 supplier, moved into a new business
model of component manufacturing with
haptic coatings. Component manufactur-
ing allows a lean manufacturing chain,
full accountability on quality and more
flexibility in the supply chain.

Introduction

The traditional manufacturing of athletic footwear is a multi‐step labor intensive process. The upper materials of a sneaker are usually composed of many different materials. The purchase of all these separate materials from different suppliers has to be coordinated carefully to meet delivery deadlines and quality expectations. In many cases minimum quantity orders, logistics, and shipment issues complicate the situation. For a TIER‐1 shoe factory, this can be a troublesome and hard to control process. In addition, the various materials have to be attached to each other. Traditionally, this is done by stitching operations, and in some cases by hot melt lamination processes. In any case, this creates a lot of manual labor and cost. Most materials are delivered as rolls and need to be cut to size before attachment. This creates cutting loss and cutting waste that is difficult to recycle.

Haptic, the new selective additive 3D
coating technology, addresses all these
above mentioned disadvantages of tradi-
tional footwear manufacturing and offers
solutions for better design, more sustain-
ability and less labor cost.1 Haptic was
introduced to the market in early 2015
and since then has shown rapid growth
and success.

Haptic Technology and
Advantages

Chemistry and Application Technology Haptic is usually applied on textile substrates based on synthetic fibers. For athletic footwear, polyester or polyester/ nylon sandwich mesh is usually the best substrate material. Haptic chemistry is based on high‐solids water-based polyurethane dispersions (PUDs).2 Curing at room temperature is achieved by mixing isocyanate hardeners into the formulation shortly before application with a pot life of 2 ‐ 4 h. The basic idea of haptic coatings is to apply a very thick 3D coating in specific areas of the substrate while other areas stay uncoated and provide full textile functionality such as breathability and flexibility. High coating thickness can be achieved by high‐solid formulations (up to 75% solids), high-viscosity thixotropic base coats, and a multi‐layer application similar to digital 3D printing technologies that have created huge attention in the market recently. However, haptic today is not applied by digital means but by screen printing technology. Both manual and automatic screen printing can be used. Special automatic screen printing machines were developed to ensure high precision printing