Unicharm has been granted a patent for a method of producing recycled pulp fibers for articles using used sanitary products. The method involves supplying a mixed solution of superabsorbent polymers and pulp fibers to a treatment tank, introducing ozone-containing gas to bleach the pulp fibers, and discharging the resulting recycled pulp fibers. The recycled pulp fibers have a 0-10 ?YI (whiteness) compared to a standard white plate. GlobalData’s report on Unicharm gives a 360-degree view of the company including its patenting strategy. Buy the report here.

Smarter leaders trust GlobalData


Premium Insights Unicharm Corp - Company Profile

Buy the Report

Premium Insights

The gold standard of business intelligence.

Find out more

According to GlobalData’s company profile on Unicharm, incontinence monitoring sensors was a key innovation area identified from patents. Unicharm's grant share as of September 2023 was 53%. Grant share is based on the ratio of number of grants to total number of patents.

Method for producing recycled pulp fibers with uniform whiteness

Source: United States Patent and Trademark Office (USPTO). Credit: Unicharm Corp

A recently granted patent (Publication Number: US11771604B2) describes a method for manufacturing recycled pulp fibers from pulp fibers of used hygiene products. The method involves several steps, including preparing a treatment tank with various ports, supplying a liquid mixture containing super absorbent polymers and pulp fibers to the treatment tank, supplying ozone-containing gas to the treatment liquid to decompose the super absorbent polymers, forming the recycled pulp fibers by bleaching the pulp fibers, and discharging the treatment liquid containing the recycled pulp fibers.

The recycled pulp fibers produced using this method have specific characteristics. They have a ?YI (brightness difference) of 0 to 10 compared to a standard white board, indicating their similarity in color. The recycled pulp fibers also have a water contact angle of 20° or less, indicating their ability to absorb water. Additionally, the recycled pulp fibers have a lignin content ratio of 0.1 mass % or less, indicating a low presence of lignin, a natural polymer in wood. The beating degree reduction speed of the recycled pulp fibers is 300 mL/h or more, indicating their suitability for further processing.

The method also addresses the issue of coloring agents in the pulp fibers. If the hygiene products used in the process contain pulp fibers with coloring agents, a colored pulp fibers removal step is included before the liquid mixture supply step. This step involves swelling the hygiene products with water, disassembling them, and separating the absorbent core. This ensures that the recycled pulp fibers do not include coloring agents.

Other aspects of the method include the use of microbubbles or nanobubbles for supplying the ozone-containing gas, continuous supply and discharge of the liquid mixture and treatment liquid, acidic treatment liquid, inactivation of super absorbent polymers with acid, and an ash content ratio of 0.65 mass % or less in the recycled pulp fibers.

The patent also describes variations of the method for manufacturing pulp fibers for saccharification, which involves using different ozone concentrations in the treatment liquid, different flow rates of the ozone-containing gas, and different CT values (product of ozone concentration and in-tank treatment time).

Overall, this patented method provides a detailed and specific process for manufacturing recycled pulp fibers from used hygiene products, ensuring the quality and characteristics of the resulting fibers.

To know more about GlobalData’s detailed insights on Unicharm, buy the report here.

Premium Insights


The gold standard of business intelligence.

Blending expert knowledge with cutting-edge technology, GlobalData’s unrivalled proprietary data will enable you to decode what’s happening in your market. You can make better informed decisions and gain a future-proof advantage over your competitors.


GlobalData, the leading provider of industry intelligence, provided the underlying data, research, and analysis used to produce this article.

GlobalData Patent Analytics tracks bibliographic data, legal events data, point in time patent ownerships, and backward and forward citations from global patenting offices. Textual analysis and official patent classifications are used to group patents into key thematic areas and link them to specific companies across the world’s largest industries.