Polymer Dispersion for Pitch Detackification in Papermaking

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Solution Overview

Problem

Natural pitch contaminants in cellulosic pulp suspensions tend to agglomerate and deposit on machinery, causing defects and production losses in papermaking due to their sticky nature, with existing solutions like talc being sensitive to shear and having poor retention properties.

Innovation Solution

An aqueous polymer dispersion comprising a hydrophobic homopolymer or copolymer of specific monomers, such as acrylic acid and styrene, is used to passivate and detackify pitch particles, combined with a styrene copolymer and optional cationic fixatives to reduce tackiness and prevent deposition.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If talc is used to control pitch deposits, then pitch attachment is reduced, but the system becomes highly sensitive to shear and talc causes felt clogging

Engineering Contradiction:

Improvepitch depositVSAvoidshear sensitivity

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The invention changes the chemical parameters by using cationic polymers with specific molecular weights and charge densities to interact with pitch particles, replacing the physical approach of talc. This chemical parameter change allows effective pitch control without the mechanical sensitivity and clogging issues of talc.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The cationic polymer acts as an intermediary substance that mediates between the hydrophobic pitch particles and the aqueous pulp suspension. The polymer's amphiphilic nature allows it to bridge the hydrophobic-hydrophilic interface, effectively controlling pitch without the drawbacks of talc.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If strongly cationic fixatives are used to fix anionic pitch contaminants, then pitch agglomeration is prevented, but the range of effective particle sizes is limited

Engineering Contradiction:

Improvepitch agglomerationVSAvoidparticle size range

Core Design Contradiction:

Object-affected harmful factorsVSAdaptability or versatility

Solution Approach 1:

The invention uses composite cationic polymers that combine multiple functional groups and structural characteristics within a single molecule. This composite structure allows the polymer to effectively interact with pitch particles across a broad size range while maintaining strong fixing capability.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The cationic polymer is designed to perform multiple functions simultaneously: it acts as a fixative for small pitch particles, a dispersant for medium-sized particles, and a flocculant for larger particles. This multi-functionality expands the effective particle size range compared to traditional fixatives.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Object-affected harmful factors

If machine wires and felts are coated with sizing agents or defoamers to enhance hydrophobizing, then pitch attachment is promoted, but wire clogging and dewatering performance reduction occur

Engineering Contradiction:

Improvepitch attachmentVSAvoiddewatering performance

Core Design Contradiction:

Object-affected harmful factorsVSProductivity

Solution Approach 1:

The invention converts the harmful hydrophobicity of pitch into a beneficial effect by using cationic polymers that exploit the hydrophobic-hydrophilic interface. The polymer's structure allows it to bind pitch particles while remaining compatible with the aqueous environment, thereby controlling pitch without compromising dewatering performance.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 polymer dispersion effectively reduces the tackiness of pitch particles, making them less likely to deposit on machinery, thereby preventing sheet defects and improving dewatering performance without the drawbacks of talc, such as shear sensitivity and foam stabilization issues.

Implementation Method 1

an aqueous polymer dispersion comprising a component A and a component B for passivating and detackifying the natural pitch particles

Methodology Applied

Scientific EffectAdsorption: Adsorption

Implementation Method 2

Fixing of the strongly anionic contaminants by means of strongly cationic fixatives (formation of what are called polyelectrolyte complexes)

Methodology Applied

Scientific EffectElectrostatic interaction: Electrostatics

Data Source

PatentEP2639350B1Method for reducing negative effects of natural pitch contaminants in both pulping and papermaking operations

Publication Date: 2017.02.22 ARCHROMA IP GMBH

AI summary

The instant invention relates to a method for inhibiting pitch deposition on pulping and papermaking equipment or machinery comprising adding to a pulp slurry containing pitch an effective amount of polymer dispersion comprising a component A and a component B, wherein component A being a homopolymer and/or copolymer of acrylic acid and/or its alkyl esters, or methacrylic acid and/or its alkyl esters, styrene and/or methylstyrene, vinyl acetate, itaconic acid, glycidyl methacrylate, 2-hydroxyalkyl (meth)acrylate, methacrylamide, N-hydroxyethyl(meth)acrylamide, dimethacrylate monomers, 1,3-butylene glycol dimethacrylate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, propylene glycol dimethacrylate, dipropylene glycol dimethacrylate, 4-methyl-1,4-pentanediol dimethacrylate, divinylbenzene and/or trivinylbenzene, and component B being an aqueous solution of a styrene copolymer with acrylic acid, maleimide and/or maleic anhydride.