Oxidized Lignocellulosic Pulp Ammonia Odor Control

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Solution Overview

Problem

Cellulose pulps used in personal care and medical care absorbent products face challenges with odor control, particularly ammonia odor from urine, which existing additives have not effectively addressed.

Innovation Solution

A process involving bleaching lignocellulosic kraft pulp with a transition metal catalyst and an oxidizing agent like hydrogen peroxide, hypochlorite, or chlorine dioxide, resulting in treated pulp with specific viscosity and functional group characteristics that enhance odor control and bacterial inhibition.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If existing additives are used to absorb odors, then odor absorption capacity is improved, but manufacturing complexity and cost increase

Engineering Contradiction:
Improveodor controlVSAvoidadditive complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent extracts and eliminates the need for separate odor-absorbing additives by directly modifying the cellulose pulp itself through oxidation treatment. The oxidation process creates aldehyde groups at C1 positions that provide inherent odor control capability, thereby taking out the requirement for additional additive components and simplifying the overall product formulation.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The oxidized cellulose pulp serves multiple functions simultaneously: it maintains the structural properties of cellulose while gaining odor control capability through the introduced aldehyde groups. This multi-functionality eliminates the need for separate odor-absorbing additives, as the cellulose itself becomes both structural and odor-control functional material.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Object-affected harmful factors

If oxidation treatment is applied to lignocellulosic material, then odor control properties are improved, but manufacturing precision and property control become more difficult

Engineering Contradiction:
Improveammonia odor controlVSAvoidproperty control
Core Design Contradiction:
Object-affected harmful factorsVSManufacturing precision

Solution Approach 1:

The patent applies parameter changes by controlling oxidation conditions (oxidizing agent type, concentration, temperature, time) to achieve specific aldehyde group concentrations at C1 positions. By adjusting these parameters, the invention optimizes the balance between odor control effectiveness and maintenance of cellulose structural properties, thereby improving manufacturing precision in oxidized pulp production.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The oxidation treatment is applied selectively to create aldehyde groups specifically at the C1 positions of cellulose chains, rather than random oxidation throughout the molecule. This local quality approach ensures that odor control functionality is concentrated where most effective, while minimizing unwanted side reactions that could compromise cellulose structural integrity and manufacturing consistency.

Inventive Principle:
Principle #3Local quality

3Productivity

If transition metal catalysts are used in oxidation process, then oxidation efficiency is improved, but potential metal contamination increases

Engineering Contradiction:
Improveoxidation efficiencyVSAvoidmetal contamination
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent uses transition metal catalysts as intermediaries to facilitate the oxidation reaction between cellulose and oxidizing agents. The metal catalysts accelerate the formation of aldehyde groups at C1 positions, improving oxidation efficiency. The catalysts are employed in controlled amounts and can be removed or deactivated after the reaction, allowing high productivity while minimizing residual metal contamination in the final product.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 treated pulp exhibits improved odor control by complexing with ammonia and inhibiting bacterial growth, maintaining paper mechanical properties, and showing enhanced wet strength and drainage.

Implementation Method 1

treating a lignocellulosic material, preferably in fibrous or particulate form and more preferably a hardwood, a softwood pulp or a combination thereof, in the presence of a transition metal catalyst with an oxidizing agent selected from a group consisting of hydrogen peroxide, hypochlorite, chlorine dioxide, hypochlorous acid and any combination thereof

Methodology Applied
Scientific EffectOxidation: Oxidation

Implementation Method 2

in the presence of a transition metal catalyst wherein the catalyst is a salt of Cu (Cu+ and Cu 2+), Fe (Fe 3+, Fe 2+) or Zn (Zn2+)

Methodology Applied
Scientific EffectCatalysis: Catalysis

Implementation Method 3

the materials control odor by complexing with odoriferous materials as for example ammonia from urine

Methodology Applied
Scientific EffectComplexation: Chemical Bonding

Implementation Method 4

or by inhibiting the growth of bacteria that convert urea into ammonia

Methodology Applied
Scientific EffectBacterial inhibition:

Data Source

PatentEP3862485B1Ligno cellulosic materials and the products made therefrom
Publication Date: 2024.02.28 INT PAPER CO

AI summary

A process comprising treating a lignocellulosic material preferably pulp in the presence of a transition metal catalyst with a oxidizing agent selected from a group consisting of hydrogen peroxide, hypochlorite, hypochlorous acid and any combination thereof to form a treated lignocellulosic material having a viscosity equal to or less than about 17 cp and having reducing functional groups selected from the group consisting of aldehyde and aldehyde type functional groups at the C6 and Cl positions but predominating at the Cl position.