Toray Industries, Inc.
Tokyo, Japan, September 29, 2022 – Toray Industries, Inc., announced today that it has created a spunbond nonwoven fabric that is persistently hydrophilic (see glossary note 1) and is gentle on the skin. This fabric is suitable for disposable diapers, masks, feminine hygiene products, and other sanitary applications. The company plans to start full-scale production when the production technology is well established.
Spunbond nonwoven fabrics for sanitary applications are normally made of polypropylene, which is softer than polyester. Since polypropylene is hydrophobic (glossary note 2), polypropylene spunbond nonwoven fabrics must be coated with hydrophilic agents for the application of diapers, masks, and feminine hygiene products. However, the coated hydrophilic agents are easily runoff from the fabrics on contact with water. Consequently, the fabrics lose hydrophilicity.
|Toray has been working on this problem through research into hydrophilizing polymer itself rather than surface treatment of the fabrics. The company has been focusing on polyester and developed special domain structures (glossary note 3) by copolymerizing polyester with a well-defined molar mass hydrophilic component. The domain structures enable to significantly improve the hydrophilicity of the polyester and result in a new spunbond nonwoven fabric that is persistently hydrophilic.
This polyester spunbond nonwoven fabric is as soft as polypropylene nonwoven fabrics, which has excellent flexibility. Persistent hydrophilicity of the fabric promotes liquid permeation without liquid remaining or spreading out on the surface. In addition, the fabric shows no cytotoxicity (glossary note 4), which is an indicator of the skin irritation. Hence, the fabric is skin-friendly and suitable for the applications such as diapers, masks, and feminine hygiene products, which have direct contact with the skin.
New spunbond fabric roll
The polyester can be polymerized using bio-based or recycled materials. Toray will push ahead with efforts to reduce environmental impact and achieve a sustainable economy. Toray will continue to provide innovative technologies and advanced materials to transform societies in keeping with its commitment to innovating ideas, technologies, and products that deliver new value.
Evaluation of hydrophilicity
1. Hydrophilic is the property of having a high affinity for water.
2. Hydrophobic is the property of repelling water.
3. The domain structure is a phase-separated structure in which there are regions clearly distinguished from other parts.
4. Cytotoxicity is the property of adversely affecting cells, such as killing or damaging.