Surface Sizing Composition for Pore-Sealed Printable Paper

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Solution Overview

Problem

Existing surface sizing agents for paper products, particularly those based on polyvinyl alcohol and acrylic acid, fail to effectively seal pores, leading to issues with ink adhesion, durability, and paper strength, while also compromising printability.

Innovation Solution

A surface sizing agent comprising polyvinyl alcohol, acrylic acid-based polymer or copolymer, a crosslinking agent, and a solvent, which forms an interpenetrating polymer network to seal pores and capillaries, enhancing paper strength and printability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If polyvinyl alcohol-based sizing agents are used to seal pores, then pore sealing is improved, but fiber accessibility to printing ink deteriorates

Engineering Contradiction:
Improvepore sealingVSAvoidfiber accessibility to printing ink
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent changes the chemical parameters of the sizing agent by using acrylic acid-based polymers with specific functional groups instead of polyvinyl alcohol, and controls the degree of polymerization and crosslinking density to achieve optimal balance between pore sealing and ink penetration

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs composite sizing agents combining acrylic acid-based polymers with specific additives that provide both pore sealing functionality and ink penetration pathways, creating a multi-functional coating system

Inventive Principle:
Principle #40Composite materials

2Shape

If high proportion of acrylic acid-based monomers is used to form surface film, then surface film formation is improved, but pore closing capability deteriorates

Engineering Contradiction:
Improvesurface film formationVSAvoidpore closing capability
Core Design Contradiction:
ShapeVSReliability

Solution Approach 1:

The patent optimizes the monomer composition parameters by combining acrylic acid-based monomers with specific copolymer components, controlling the molecular weight distribution and crosslinking density to achieve simultaneous surface film formation and pore closing

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses composite polymer systems combining acrylic acid-based polymers with other polymer components that have complementary properties, where one component provides surface film formation while another provides pore closing capability

Inventive Principle:
Principle #40Composite materials

3Strength

If surface sizing is applied to improve strength properties, then tear resistance and wet abrasion resistance are improved, but printability deteriorates

Engineering Contradiction:
Improvetear resistance and wet abrasion resistanceVSAvoidprintability
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The patent creates local quality differentiation in the sizing coating by using polymers with specific functional groups that provide strength enhancement in certain regions while maintaining porosity and ink penetration pathways in other regions, achieving spatially differentiated functionality

Inventive Principle:
Principle #3Local quality

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 solution provides a paper product with sealed pores and capillaries, improved durability, and enhanced printability, ensuring stable ink adhesion and reduced ink spread, while maintaining high strength and resistance to wet creasing.

Implementation Method 1

a surface sizing agent comprising at least one polyvinyl alcohol, a dispersion comprising at least one acrylic acid-based polymer and/or at least one acrylic acid-based copolymer, at least one crosslinking agent for the acrylic acid-based polymer and/or acrylic acid-based copolymer

Methodology Applied
Scientific EffectCrosslinking: Chemical Bonding

Implementation Method 2

which forms an interpenetrating polymer network to seal pores and capillaries

Methodology Applied
Scientific EffectInterpenetrating polymer network formation: Composite Materials

Implementation Method 3

the surface of the paper product is sizing to reduce capillarity, i.e., to close the pores of the paper product

Methodology Applied
Scientific EffectCapillarity reduction: Capillary Action

Implementation Method 4

The at least one acrylic acid-based polymer and/or the at least one acrylic acid-based copolymer and/or their crosslinked structure promote the adhesion of applied printing inks

Methodology Applied
Scientific EffectAdhesion: Adhesive

Data Source

PatentEP3762542B1Surface sizing agent for a paper product, use thereof, paper product, and method for coating a paper product
Publication Date: 2025.12.17 GIESECKE & DEVRIENT CURRENCY TECHNOLOGY GMBH

AI summary

The invention relates to a surface sizing agent for a paper product containing: - at least one polyvinyl alcohol, - a dispersion comprising at least one polymer based on acrylic acid and/or at least one copolymer based on acrylic acid, - at least one cross-linking agent for the polymer based on acrylic acid and/or copolymer based on acrylic acid, and - at least one solvent.