Sheet Forming Binder Segmentation for Whiteness and Strength
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Solution Overview
Problem
Existing dry papermaking processes face challenges in achieving high-strength sheets due to reduced resin content when using high-content white pigments, which can lead to weakened sheet strength.
Innovation Solution
A sheet forming binder comprising a first powder with a smaller volume average particle size and a second powder with a larger particle size, where the first powder contains a fluorescent brightening agent and titanium dioxide, and the second powder has a higher resin content, is used to create a mixture that is mixed with fibers and formed into a sheet by heating, optimizing the proportion and particle sizes to enhance whiteness and strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If high-content white pigment is used to achieve high whiteness, then whiteness is improved, but resin content is reduced and sheet strength deteriorates
Solution Approach 1:
The binder is segmented into two distinct powder components: first powder (fine particles, 5.0 μm or less) containing fluorescent brightening agent and titanium dioxide for whiteness, and second powder (coarse particles, 10.0 μm or more) containing resin for strength. This segmentation allows each component to specialize in one function, resolving the contradiction between whiteness and strength.
Solution Approach 2:
Different regions of the binder have different compositions optimized for specific functions: the first powder provides optical properties (whiteness) while the second powder provides mechanical properties (strength). This local quality differentiation allows simultaneous achievement of high whiteness and high sheet strength.
2Strength
If resin content is increased to improve sheet strength, then sheet strength is improved, but white pigment content is reduced and whiteness deteriorates
Solution Approach 1:
The binder is divided into two powder types with distinct size ranges and functional compositions. The second powder (coarse) is optimized for resin content and bonding strength, while the first powder (fine) is optimized for pigment content and whiteness. This segmentation enables independent optimization of both strength and whiteness without compromise.
Solution Approach 2:
The binder itself is a composite material consisting of two different powder components with complementary functions. This composite structure allows the system to simultaneously achieve properties that would be mutually exclusive in a homogeneous material, specifically high resin content for strength and high pigment content for whiteness.
3Device complexity
If single-powder binder is used to simplify composition, then device complexity is reduced, but ability to simultaneously achieve high whiteness and high strength deteriorates
Solution Approach 1:
Rather than using a single complex powder mixture, the binder is segmented into two simpler, well-defined powder components with distinct size ranges and compositions. This segmentation actually reduces complexity by creating clear functional divisions while achieving superior performance in both whiteness and strength.
Solution Approach 2:
The invention changes the particle size parameter as a key differentiator between the two powders. By establishing clear size boundaries (first powder ≤5.0 μm, second powder ≥10.0 μm), the system simplifies composition control while enabling distinct functional roles that simultaneously achieve high whiteness and high 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 proposed solution effectively increases the whiteness and strength of the resulting sheet by ensuring a sufficient resin content while maintaining high whiteness, outperforming comparative examples with inadequate resin or pigment proportions.
Implementation Method 1
the first powder may contain a fluorescent brightening agent
Implementation Method 2
the first powder may contain titanium dioxide as an inorganic pigment with a content of 30.0% by mass or more
Implementation Method 3
a sheet forming section configured to form the mixture deposited in the depositing section into a sheet by heating the mixture
Data Source
AI summary
A sheet forming binder includes a first powder and a second powder having a larger volume average particle size than the first powder. The proportion of the first powder is 10.0% by mass or more relative to the total mass of the first powder and the second powder.