Microcapsule Aqueous Ink Composition for Greasy Paper Writing
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Solution Overview
Problem
Aqueous ink compositions for writing instruments using microcapsule pigments are prone to repel on paper surfaces with hand grease, leading to uneven line density and poor writing performance.
Innovation Solution
An aqueous ink composition containing colored resin particles encapsulating a pigment, with a preferred content ratio of pigment to resin particles, and optionally including synergists, is used to enhance adhesion and uniformity on greasy surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If microcapsule pigments with general dyes or pigments are used, then particle diameter adjustment is easy, but the ink is repelled on paper faces with hand grease causing uneven line density
Solution Approach 1:
The patent changes the chemical composition parameters of the microcapsule wall by incorporating specific polymers (polyvinyl alcohol, carboxymethyl cellulose, or starch derivatives) with particular molecular weights and ratios. This modifies the surface properties and adhesion characteristics of the pigment particles, enabling them to adhere properly to greasy paper surfaces while maintaining ease of particle diameter adjustment through conventional microencapsulation techniques.
Solution Approach 2:
The patent creates a composite microcapsule wall structure combining multiple components: polymer matrices (polyvinyl alcohol, carboxymethyl cellulose), crosslinking agents (polyisocyanate), and pigment cores. This composite structure integrates the advantages of each component - the polymer provides adhesion and surface control, the crosslinking agent enhances structural integrity, and the pigment core provides coloration, collectively solving the adhesion problem on greasy surfaces.
2Reliability
If conventional microcapsule pigments are used, then pigment encapsulation is achieved, but writing capability is poor due to repulsion on greasy surfaces
Solution Approach 1:
The patent optimizes parameters including the molecular weight of polyvinyl alcohol (50,000-1,000,000), the ratio of crosslinking agent to polymer (0.1-10 times), and the pigment loading concentration (0.1-10 mass%). These parameter adjustments modify the microcapsule wall properties to enhance adhesion to greasy surfaces while maintaining proper encapsulation, thereby improving writing capability without compromising pigment encapsulation integrity.
Solution Approach 2:
The patent introduces polyvinyl alcohol and carboxymethyl cellulose as intermediary substances that form a bridging layer between the pigment particles and the paper surface. These intermediaries with specific hydrophilic properties facilitate adhesion to greasy surfaces while maintaining the encapsulation function, thus mediating between the conflicting requirements of encapsulation and writing performance.
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 ink composition provides uniform line density and excellent writing capability on paper with hand grease, preventing repulsion and maintaining ink stability.
Implementation Method 1
the aqueous ink composition for writing instruments of the present disclosure contains at least a pigment (a) and colored resin particles (A) encapsulating the pigment (a)... which is not repelled when the aqueous ink composition for writing instruments is used to write on a paper face attached with hand grease
Data Source
AI summary
An aqueous ink composition for writing instruments may contain colored resin particles encapsulating a pigment, wherein the ink is not repelled when the aqueous ink composition for writing instruments is used to write on a paper face attached with hand fingers or the like, and achieves a uniform density in a drawn line and excellent writing capability. An embodiment of the aqueous ink composition for writing instruments is an aqueous ink composition for writing instruments containing at least a pigment (a) and colored resin particles (A) encapsulating the pigment (a).