Biodegradable Sanitary Napkin Absorbent Core Design

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Solution Overview

Problem

Existing sanitary napkins face challenges in achieving sufficient absorption capacity using only biologically degradable materials without increasing thickness or causing unpleasant wetness, as replacing all synthetic ingredients with biodegradable ones reduces absorption capacity, and adding more absorbent layers is not aesthetically acceptable.

Innovation Solution

A sanitary napkin design featuring a biodegradable absorbent core made of non-woven natural plant fibers with a unique folded structure, integrated between a biodegradable liquid impermeable bottom layer and a liquid permeable top layer, which enhances absorption capacity and distribution while maintaining a slim profile and comfortable fit.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If all artificial ingredients are replaced with biologically degradable ingredients, then environmental compatibility is improved, but absorption capacity becomes insufficient

Engineering Contradiction:
Improveenvironmental compatibilityVSAvoidabsorption capacity
Core Design Contradiction:
Object-affected harmful factorsVSQuantity of substance

Solution Approach 1:

The absorbent core uses a composite structure combining natural plant fibers (cellulose, cotton, bamboo) with synthetic fibers (polyester, polyamide) in specific ratios. This composite approach allows the napkin to maintain sufficient absorption capacity while incorporating biodegradable materials, resolving the contradiction between environmental compatibility and absorption performance.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent optimizes parameters such as fiber diameter, fiber length, and material composition ratios to enhance absorption capacity. By carefully controlling these parameters, the napkin achieves adequate absorption using biodegradable materials, preventing the need to replace all synthetic ingredients while still improving environmental compatibility.

Inventive Principle:
Principle #35Parameter changes

2Quantity of substance

If more absorbent layers are added to increase absorption capacity, then absorption performance is improved, but thickness is enlarged causing unpleasant filing and poor discretion

Engineering Contradiction:
Improveabsorption capacityVSAvoidthickness
Core Design Contradiction:
Quantity of substanceVSLength of stationary object

Solution Approach 1:

The absorbent core features a non-uniform structure with a central area and two lateral longitudinal areas of different widths. This local variation in geometry concentrates absorption capacity in specific regions while maintaining overall thinness, allowing high absorption performance without increasing the napkin's thickness and causing discomfort.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

Instead of increasing thickness by adding more layers, the patent optimizes the three-dimensional arrangement and geometry of the absorbent core layers. The folded structure and overlapping areas create efficient absorption pathways within a thin profile, achieving high absorption capacity without compromising discretion or comfort.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Length of stationary object

If the napkin is made thinner to improve discretion and comfort, then aesthetic acceptability is improved, but absorption capacity becomes insufficient

Engineering Contradiction:
ImprovethicknessVSAvoidabsorption capacity
Core Design Contradiction:
Length of stationary objectVSQuantity of substance

Solution Approach 1:

The absorbent core is divided into multiple layers with different functions: a liquid impermeable bottom layer, a liquid permeable top layer, and an absorbent core with specific fiber composition. This segmentation allows each layer to be optimized for its specific function, achieving sufficient absorption capacity within a thin overall structure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The absorbent core utilizes porous non-woven fibers with optimized porosity to maximize absorption capacity within a thin structure. The porous structure allows rapid fluid penetration and distribution while maintaining a slim profile that is comfortable and discrete for the user.

Inventive Principle:
Principle #31Porous materials

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The napkin achieves sufficient absorption and distribution of menstrual fluid without the unpleasant feeling of a fully saturated pad, using biodegradable materials that maintain regular use frequency and economic viability.

Implementation Method 1

an absorbent core, which is placed over said bottom layer... Said intermediate layer is intended for distribution of the liquid, which is absorbed within the absorbent core

Methodology Applied
Scientific EffectCapillary action: Capillary Action

Implementation Method 2

a liquid permeable top layer, which is adapted for being placed onto skin or mucosa of the human body

Methodology Applied
Scientific EffectPermeation: Permeation

Data Source

PatentEP4057964B1Sanitary napkin
Publication Date: 2023.08.16 TOSAMA TOVARNA SANITETNEGA MATERIALA D O O
  • EP4057964B1 patent drawingFigure 1
  • EP4057964B1 patent drawingFigure 2~3

AI summary

The purpose of the invention is to conceive a sanitary napkin (1) suitable for absorbing of a pre-determined quantity of liquid substance, in particular of human secretions and in particular of menstrual fluid, which should be placeable onto the external surface of human body, namely between the skin or mucosa and each disposable underwear, and which should assure accurate and sufficient absorptiveness comparable to other state of the art napkins by simultaneously uniformly distributing and retaining of each absorbed fluid and avoiding unpleasant perception of contacting a totally wet pad, and which should consist of materials, which are biologically degradable within a reasonable time period, and preferably of natural plant raw materials. Sanitary napkin (1) comprises a liquid impermeable bottom layer (11), which consists of a biologically degradable material and is during the use faced away from the user and supposed for being in contact with the underwear of each user, a liquid permeable top layer (12), which consists of a biologically degradable material and is during the use faced towards the user and is adapted for being in contact with the skin or mucosa of each user, as well as an absorbent core (13), which is placed between both previously mentioned layers (11, 12) and is adapted for absorbing of a predetermined quantity of liquid, in particular of human excrements, in particular of menstrual liquid. Said absorbent core (13) is integrally conceived and consists of a longitudinal section of a band (130) consisting of non- woven biologically degradable natural plant fibers and having a pre-determined weight per length unit.