Water-Dispersible Paper With Segmented Softwood Pulp Layers
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Solution Overview
Problem
Existing water-dispersible papers face challenges in achieving excellent dispersibility in water while maintaining printability and having a lower environmental impact, often at a higher cost.
Innovation Solution
A water-dispersible paper is developed with a base paper containing a bulky layer of 10% or higher softwood pulp with a lumen to fiber diameter ratio of 0.60 or lower and a dense layer with 30% or higher softwood pulp, along with a water-soluble polymer impregnated into the paper, enhancing dispersibility and printability while reducing environmental burdens.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional water-dispersible papers use refined and unrefined pulp mixtures, then dispersibility in water is achieved, but printability and surface quality deteriorate
Solution Approach 1:
The paper is divided into distinct layers: a bulky layer containing water-dispersible pulp fibers for rapid water dispersibility, and a dense layer providing a smooth printing surface. This segmentation allows each layer to perform its specific function independently, resolving the contradiction between dispersibility and printability
Solution Approach 2:
Different regions of the paper have different properties: the bulky layer has high porosity and water solubility for dispersibility, while the dense layer has low porosity and high smoothness for printability. This local differentiation of quality allows the paper to exhibit both excellent dispersibility and printability simultaneously
2Object-affected harmful factors
If water-dispersible papers use high biomaterial content, then environmental burden is reduced, but production cost increases
Solution Approach 1:
The invention optimizes the composition parameters by using 5-50 wt% water-dispersible pulp in the bulky layer and 30-70 wt% softwood pulp in the dense layer, achieving the right balance between environmental friendliness and production cost. This parameter optimization allows high biomaterial content while maintaining cost-effectiveness
3Ease of operation
If water-dispersible papers use softwood pulp with specific lumen to fiber diameter ratio, then dispersibility is improved, but structural integrity may worsen
Solution Approach 1:
The paper uses a composite structure combining softwood pulp with specific lumen to fiber diameter ratios (0.40≤1/D<0.65) in the bulky layer with other pulp types, creating a composite material that maintains both dispersibility and structural integrity. The composite approach allows the softwood pulp to provide dispersibility while other components contribute to strength
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 paper exhibits excellent dispersibility in water, improved printability, and lower environmental impact due to its high biomaterial composition and specific pulp ratios, with a cost-effective production process.
Implementation Method 1
a water-soluble polymer impregnated into this base paper
Data Source
Figure 1
AI summary
An object is to provide a water-dispersible paper that exhibits excellent dispersibility in water. As a solution, a water-dispersible paper is provided, which has: a base paper that has a bulky layer containing 10% by weight or higher of a softwood pulp with a lumen width (l) to fiber diameter (D) ratio (l/D) of 0.60 or lower on average; and a water-soluble polymer impregnated into the base paper.