High-Solid Cellulosic Nanomaterial Screen Printing for Even Films

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Solution Overview

Problem

Existing film and coating manufacturing techniques for cellulosic nanomaterials face challenges with high viscosity and require dilute suspensions, leading to complications in dewatering and drying, and result in non-homogeneous films or coatings.

Innovation Solution

A screen printing process using a high solid content and high viscosity suspension, facilitated by a screen printing press, allows for the production of films and coatings with improved homogeneity and even surfaces, utilizing methods like post-healing and post-leveling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If dilute suspensions of cellulosic nanomaterial are used, then the viscosity is low and easy to process, but the dewatering and drying requires considerable energy input and is complicated

Engineering Contradiction:
Improveenergy input for dewatering and dryingVSAvoidsolid content of suspension
Core Design Contradiction:
Use of energy by moving objectVSQuantity of substance

Solution Approach 1:

The patent changes the fundamental parameter of suspension concentration from dilute to high solid content (≥2 wt-% dry content). By using high solid content suspensions with viscosity between 150-200,000 mPas, the process eliminates the need for energy-intensive dewatering and drying operations while maintaining processability through the screen printing technique.

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If highly dilute suspensions are used to avoid nozzle clogging, then the suspension can be applied easily, but the dewatering or drying of the film is complicated and requires considerable energy input

Engineering Contradiction:
Improveease of suspension applicationVSAvoidenergy input for drying
Core Design Contradiction:
Ease of manufactureVSUse of energy by stationary object

Solution Approach 1:

The patent adopts screen printing as an alternative manufacturing technique that copies the successful application method of dilute suspensions while using high solid content material. The screen printing process allows high solid content suspensions to be applied easily without nozzle clogging issues, eliminating the need for energy-intensive drying operations.

Inventive Principle:
Principle #26Copying

3Manufacturing precision

If conventional film manufacturing techniques are used, then the process is established, but the films are non-homogeneous and have uneven surfaces

Engineering Contradiction:
Improvehomogeneity of film surfaceVSAvoidprocess complexity
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent employs post-healing and post-leveling processes that allow the high solid content suspension to self-adjust and level itself during the screen printing process. This self-service mechanism ensures homogeneous film formation with even surfaces without requiring complex additional processing steps.

Inventive Principle:
Principle #25Self-service

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 process enables the production of films and coatings with high cellulosic nanomaterial content, achieving a more homogeneous and even surface, while reducing energy consumption and avoiding nozzle clogging.

Implementation Method 1

using the suspension of step a) to print a coating or film using a screen printing press

Methodology Applied
Scientific EffectScreen printing:

Implementation Method 2

a Brookfield viscosity of from 150 mPas to 200000 mPas

Methodology Applied
Scientific EffectViscosity:

Implementation Method 3

optionally dewatering and/or drying the coating or film prepared in step b)

Methodology Applied
Scientific EffectEvaporation: Evaporation

Data Source

PatentUS12371582B2Process for production of film or coating comprising cellulosic nanomaterial
Publication Date: 2025.07.29 STORA ENSO OYJ

AI summary

The present invention is directed to a process for manufacturing a film or coating comprising high amounts of cellulosic nanomaterial. According to the present invention, a screen printing press, such as a rotary screen press, is used to create a film or coating comprising cellulosic nanomaterial. One benefit of the present process is that the suspension used in the printing process has a high dry content and high viscosity, thereby facilitating the process for manufacturing a film or coating comprising high amounts of cellulosic nanomaterial.