Patterned Microsphere Coating for Retroreflectivity Control

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional microsphere-coated articles and transfer carriers face challenges in achieving improvements in haze, clarity, and cost reduction while maintaining surface durability and wear resistance, particularly in applications requiring thermoformability and stain resistance.

Innovation Solution

A microsphere-coated article with a monolayer of randomly distributed microspheres arranged in a predetermined pattern, combined with a bead bonding layer, where the microspheres are partially embedded in the layer to form a patterned surface that reduces retroreflectivity and enhances durability and optical clarity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a continuous monolayer of microspheres is applied to achieve surface durability and wear resistance, then surface protection is improved, but retroreflectivity increases and optical clarity deteriorates

Engineering Contradiction:

Improvesurface durabilityVSAvoidretroreflectivity

Core Design Contradiction:

ReliabilityVSIllumination intensity

Solution Approach 1:

The continuous monolayer of microspheres is segmented into discrete randomly distributed microspheres spaced apart from each other, creating gaps that reduce retroreflectivity while maintaining surface durability through the remaining microsphere coverage

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the surface have different microsphere densities - areas requiring higher protection have denser microsphere coverage while areas requiring better optical clarity have sparser coverage, optimizing both durability and visual properties locally

Inventive Principle:

Principle #3Local quality

2Reliability

If a continuous monolayer of microspheres is applied to ensure wear resistance, then surface protection is improved, but material cost increases

Engineering Contradiction:

Improvewear resistanceVSAvoidmicrosphere coverage

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The continuous microsphere layer is segmented into discrete randomly distributed microspheres, reducing the total quantity of microspheres required while maintaining protective function through strategic placement and the bead bonding layer

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Instead of applying a complete continuous monolayer, partial coverage with randomly distributed microspheres is used, providing sufficient protection through the bead bonding layer while reducing material consumption and cost

Inventive Principle:

Principle #16Partial or excessive action

3Reliability

If a continuous monolayer of microspheres is applied to achieve uniform protection, then surface durability is improved, but optical clarity and visibility deteriorate

Engineering Contradiction:

Improvesurface protectionVSAvoidoptical clarity

Core Design Contradiction:

ReliabilityVSIllumination intensity

Solution Approach 1:

The uniform continuous monolayer is segmented into discrete randomly distributed microspheres with spacing between them, allowing light to pass through gaps and improving optical clarity while maintaining protection through the distributed microsphere network and bead bonding layer

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The surface transitions from uniform microsphere coverage to variable local density, with randomly distributed microspheres providing protection where needed while allowing optical clarity in other areas, optimizing both properties through spatial variation

Inventive Principle:

Principle #3Local quality

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 solution provides a durable, abrasion-resistant, and optically clear surface with reduced microsphere coverage, enabling cost savings and improved visibility, while maintaining the protective properties of continuous microsphere coatings.

Implementation Method 1

a monolayer of randomly distributed microspheres arranged in a predetermined pattern

Methodology Applied

Scientific EffectRandom distribution:

Implementation Method 2

a bead bonding layer disposed on the microsphere layer, wherein the plurality of microspheres are partially embedded in a first major surface of the bead bonding layer

Methodology Applied

Scientific EffectAdhesion: Adhesive

Implementation Method 3

the article has a retroreflectivity (Ra) of less than 5.0 candelas/lux/square meter

Methodology Applied

Scientific EffectRetroreflectivity reduction:

Data Source

PatentUS11413846B2Article featuring a predetermined pattern of randomly distributed microspheres and methods of making the same

Publication Date: 2022.08.16 3M INNOVATIVE PROPERTIES CO

AI summary

Described herein is an article having a microsphere layer comprising a monolayer of microspheres, the monolayer of microspheres comprising a first area substantially free of microspheres and a second area comprising a plurality of randomly-distributed microspheres, wherein the monolayer of microspheres comprises a predetermined pattern, the predetermined pattern comprises at least one of (i) a plurality of the first areas, (ii) a plurality of the second areas, and (iii) combinations thereof; and (b) a bead bonding layer disposed on the microsphere layer, wherein the plurality of microspheres are partially embedded in a first major surface of the bead bonding layer, wherein the article has a retroreflectivity (Ra) of less than 5.0 candelas/lux/square meter. Also disclosed herein are transfer carriers and methods of making the articles and transfer carriers.