Ink Composition for Sandpaper Printing

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Solution Overview

Problem

Existing printing methods for nail care products like nail grinding pads result in oil-based ink films that reduce grinding efficiency and water-based inks that bleed and mix colors, compromising the sandpaper's effectiveness and appearance.

Innovation Solution

A printing method using an ink composition of 60-80% polypropylene glycol and its derivatives, 2-10% solvent dye or pigment, 1-4% ethanol, and 0.1-1% surfactant, applied via an inkjet plotter printer, which absorbs into the sandpaper without forming a film and prevents color bleeding by using immiscible polymers for aqueous phase separation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If oil based ink is used to print designs on the sandpaper face, then designs and artwork can be applied, but the grinding efficiency of the sandpaper surface decreases

Engineering Contradiction:
Improveprinting capabilityVSAvoidgrinding efficiency
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent changes the chemical composition parameters of the ink by using water-based inks instead of oil-based inks, and specifically formulates the ink with polymers having controlled molecular weights (200-2000 daltons) and specific chemical structures (polypropylene glycol, polyethylene glycol, carboxymethyl cellulose, starch). This parameter change allows the ink to be absorbed into the sandpaper pores without forming a surface film, thus maintaining grinding efficiency while enabling printing.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent utilizes the porous structure of sandpaper by formulating ink compositions that are specifically designed to be absorbed into the pores of the sandpaper surface. The ink vehicles (water, alcohols, glycols) and polymer additives work together to enable deep penetration into the porous structure, ensuring the ink resides within the pores rather than on the surface, thereby preserving the abrasive properties.

Inventive Principle:
Principle #31Porous materials

2Reliability

If water based inks are used to print designs on the sandpaper face, then grinding efficiency is maintained, but colors bleed into neighboring colors

Engineering Contradiction:
Improvegrinding efficiencyVSAvoidcolor separation
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent employs composite ink formulations that combine water-based vehicles with specific polymer additives (polypropylene glycol, polyethylene glycol, carboxymethyl cellulose, or starch) having controlled molecular weights. This composite approach creates an ink system where the polymers provide structure and binding properties that prevent color bleeding, while the water-based formulation maintains grinding efficiency. The composite nature of the ink allows simultaneous achievement of both goals.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent addresses color bleeding by changing the physical-chemical parameters of the water-based ink through the addition of polymers with specific molecular weight ranges (200-2000 daltons). These polymer additives modify the rheological properties, drying characteristics, and binding strength of the ink, enabling sharp color boundaries without compromising the water-based nature of the ink that maintains grinding efficiency.

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If ink forms a film on the sandpaper surface, then printing quality improves, but the roughness of the sandpaper surface is lost

Engineering Contradiction:
Improveprinting qualityVSAvoidsurface roughness
Core Design Contradiction:
Manufacturing precisionVSShape

Solution Approach 1:

The patent fundamentally addresses the film formation issue by designing ink compositions specifically optimized for porous substrate absorption. The ink vehicles (water, alcohols, glycols) and polymer additives work synergistically to enable rapid penetration into the sandpaper pores, ensuring the ink is absorbed into the bulk material rather than forming a surface film. This approach maintains the three-dimensional roughness of the sandpaper surface while achieving high-quality printing through the porous structure.

Inventive Principle:
Principle #31Porous materials

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 method maintains the sandpaper's grinding efficiency, prevents color bleeding, and produces high-quality, durable prints without affecting the filing characteristics, allowing for both opaque and translucent designs on nail grinding pads.

Implementation Method 1

ink is absorbed into the grinding face without forming a film on the grinding face

Methodology Applied
Scientific EffectCapillary action: Capillary Action

Implementation Method 2

printing and drying the inks at the same time by heating the heat rays in the plotter area located directly under the side to be sprayed

Methodology Applied
Scientific EffectEvaporation: Evaporation

Data Source

PatentUS9102181B2Method for printing designs on sandpaper
Publication Date: 2015.08.11 BODI CORP

AI summary

A method of printing on the sandpaper face of a nail grinding pad comprises printing, with an inkjet plotter printer onto a sandpaper surface, an ink composition including: 60% to 80% by weight of a polymer selected from the group consisting of: polypropylene glycol and its derivatives whose minimum molecular weight is around 200; polysaccharide and its derivatives; polyvinyl alcohol and its derivatives whose average molecular weight is around 10,000 to 200,000; polysucrose and its derivatives whose average molecular weight is around 40,000 to 400,000; and epoxy glycerol propoxylated glycerol and their derivatives whose average molecular weight is 500 to 10,000; and 2% to 10% by weight of a solvent dye or a pigment; 1% to 5% by weight percent of ethanol; and 0.1% to 1.0% by weight percent of surfactants.