Capped Oligomer Nail Coatings for Scratch Resistance and Removability

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Solution Overview

Problem

Existing nail coatings based on uncapped oligomers require careful formulation and stabilization to prevent side reactions and UV-light induced cross-linking, and are difficult to remove without damaging the nail surface.

Innovation Solution

Compositions containing capped oligomers, such as Bis-Ethylhexanol Poly(1,4-Butanediol)-13/IPDI Copolymer or Bis-Ethylhexanol Poly(Caprolactone Neopentyl Glycol)/IPDI Copolymer, which provide improved adhesion, durability, and scratch resistance without the need for UV-light induced cross-linking, and can be formulated into multiple layers for enhanced performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If uncapped oligomers are used in photo-reactive coatings, then scratch resistance and adhesion are improved, but side reactions and pre-polymerization occur requiring careful formulation and stabilization

Engineering Contradiction:
Improvescratch resistanceVSAvoidformulation stability
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The oligomers are pre-modified with cap groups during synthesis to block reactive sites before the final product is formulated. This preliminary capping action prevents side reactions and pre-polymerization during storage and handling, while allowing controlled crosslinking only when desired through subsequent deprotection or curing processes.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

Cap groups serve as intermediary protective elements that temporarily block reactive oligomer ends. These cap groups can be removed or activated under controlled conditions to enable crosslinking, thus mediating between the need for stability during formulation and the need for reactivity for crosslinking.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Duration of action of stationary object

If uncapped oligomers with UV photoinitiators are used, then durable crosslinked coating is formed, but removal becomes difficult and may damage nail surface

Engineering Contradiction:
Improvecoating durabilityVSAvoidremoval ease
Core Design Contradiction:
Duration of action of stationary objectVSEase of manufacture

Solution Approach 1:

The cap groups are introduced in advance to control the crosslinking process. By designing the cap groups to be removable under specific conditions (such as chemical treatment or controlled hydrolysis), the coating can be made durable during use but also designed for controlled removal without requiring harsh mechanical scraping or prolonged solvent exposure that damages nails.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The chemical structure of the oligomers is designed with adjustable parameters including the type of cap groups, the density of crosslinkable sites, and the strength of crosslinks. By tuning these parameters, the coating can achieve optimal balance between durability during wear and ease of removal when needed, avoiding extreme hardness that causes cracking and difficulty in removal.

Inventive Principle:
Principle #35Parameter changes

3Strength

If higher oligomer content is used to improve adhesion and durability, then coating performance improves, but flexibility decreases and cracking may occur

Engineering Contradiction:
ImproveadhesionVSAvoidflexibility
Core Design Contradiction:
StrengthVSStability of the object's composition

Solution Approach 1:

The oligomer molecular weight, functional group density, and cap group type are adjusted as compositional parameters to achieve optimal balance. By controlling these parameters, the formulation achieves sufficient crosslinking for adhesion and durability while maintaining adequate flexibility to prevent cracking under normal wear conditions.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The coating formulation combines capped oligomers with other compatible polymers, plasticizers, or modifiers to create a composite system. This composite approach allows the oligomer crosslinks to provide adhesion and durability while the other components maintain flexibility and reduce brittleness, preventing cracking.

Inventive Principle:
Principle #40Composite materials

Data Source

PatentEP3402461B1Nail composition with capped oligomers
Publication Date: 2021.12.01 REVLON CONSUMER PRODUCTS LLC
  • EP3402461B1 patent drawingFigure 1

AI summary

The present disclosure relates generally to a composition comprising at least one capped oligomer, at least one solvent, at least one film former, and at least one monomer or polymer, said composition having a 2 hour sward hardness < 10 and > 1 when applied to a glass plate.