Continuous Fiber-Polymer Composite Production Process

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Solution Overview

Problem

Current processes for manufacturing composite materials from natural fibers and thermoplastic polymers face challenges such as inefficient energy use, high manual intervention, and difficulty in scaling up production, particularly in drying and handling materials with low bulk density, which affects the production of thermomechanical pulp (TMP) and chemi-thermomechanical pulp (CTMP) composites.

Innovation Solution

A continuous process involving the introduction of fibers from refiner pulp, TMP, or CTMP into a flash tube dryer, separation in a cyclone, compaction to increase bulk density, and mixing with thermoplastic polymers, followed by pelletization, which allows for efficient production without excessive energy use and manual intervention, enabling the production of composite products with improved mechanical properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If fibers are dried in a flash tube dryer, then the drying efficiency is improved, but the bulk density of the dried fibers decreases

Engineering Contradiction:
Improvedrying efficiencyVSAvoidbulk density
Core Design Contradiction:
Use of energy by moving objectVSVolume of moving object

Solution Approach 1:

The fibers are pre-treated in the refiner to optimize their physical properties before drying, which allows for more efficient drying while minimizing bulk density loss. The refiner prepares the fibers by controlling fiber length, lignin content, and surface properties, creating optimal conditions for subsequent flash drying.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The drying process parameters are optimized by controlling temperature, residence time, and air flow rate in the flash tube dryer. By adjusting these parameters, the process achieves high drying efficiency while minimizing the degradation of bulk density. The rapid drying time prevents excessive fiber bond formation that would reduce bulk density.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If a continuous process is implemented, then productivity is improved, but the complexity of the process increases

Engineering Contradiction:
Improveproduction efficiencyVSAvoidprocess complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

Multiple process functions are combined into integrated equipment units. The refiner-blowlow system is directly connected to the flash tube dryer, which is connected to the cyclone separator, creating a continuous integrated process line. This merging reduces the number of separate operations and manual interventions while maintaining high productivity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The process is designed as a continuous operation where fibers flow continuously from the refiner through the dryer and separator without interruption. This continuous action eliminates batch processing steps and manual loading/unloading operations, significantly improving productivity despite the complexity of maintaining continuous operation across multiple stages.

Inventive Principle:
Principle #20Continuity of useful action

3Ease of operation

If manual intervention is reduced, then ease of operation is improved, but the difficulty of controlling the process increases

Engineering Contradiction:
Improveautomation levelVSAvoidprocess control difficulty
Core Design Contradiction:
Ease of operationVSDifficulty of detecting and measuring

Solution Approach 1:

The process incorporates feedback control mechanisms where process parameters such as fiber moisture content, bulk density, and flow rate are continuously monitored and adjusted. Sensors detect variations in the fiber stream and provide feedback to control systems that automatically adjust dryer parameters, separator settings, and compactor operation to maintain optimal process conditions without manual intervention.

Inventive Principle:
Principle #23Feedback

4Strength

If fiber length is preserved, then strength properties are improved, but the handling difficulty increases due to low bulk density

Engineering Contradiction:
Improvetensile strengthVSAvoidhandling ease
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The handling process is segmented into distinct stages: gentle conveying from the refiner to the dryer, separate processing in the cyclone separator, and controlled compaction. Each stage is designed to minimize fiber damage and maintain fiber length while managing the low bulk density characteristic. The segmentation allows for optimized handling at each stage without compromising fiber integrity.

Inventive Principle:
Principle #1Segmentation

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

This process enables the production of composite materials with enhanced mechanical properties and scalability, reducing energy consumption and manual handling, while maintaining the strength and stiffness of TMP or CTMP fibers, and facilitating the use of renewable raw materials.

Implementation Method 1

introducing fibers from the blowline or from the housing of a refiner, into a flash tube dryer

Methodology Applied
Scientific EffectFlash drying: Evaporation

Implementation Method 2

separating the dried fibers obtained in step a) from humid air in a cyclone

Methodology Applied
Scientific EffectCyclone separation: Cyclone Separation

Data Source

PatentEP3377562B1Process for producing fiber-polymer-composites
Publication Date: 2023.01.11 STORA ENSO OYJ
  • EP3377562B1 patent drawingFigure 1
  • EP3377562B1 patent drawingFigure 2
  • EP3377562B1 patent drawingFigure 3

AI summary

The present invention relates to a process for the manufacturing of composite materials from natural fibers and thermoplastic polymers. Examples of fibers are wood fibers originating from pulping processes known as refiner pulp (RMP),thermomechanical pulp (TMP) or chemi-thermomechanical pulp (CTMP),but the process can also be applied to other kinds of natural fiber containing raw materials. In the process according to the present invention, fibers are introduced from the blowline or the housing of a refiner into a flash tube dryer, separated from humid air in a cyclone, introduced into a compounder and mixed with at least one thermoplastic polymer and the product is subsequently pelletized. The process according to the present invention is advantageously run as a continuous process.