Inner Surface Sol-Gel Barrier for Cosmetic Containers
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Solution Overview
Problem
Existing methods for manufacturing glass containers for pharmaceutical and cosmetic products face challenges such as high manufacturing costs, fragility, and contamination risks due to ion migration from non-neutral glass, while internal coatings struggle with durability and hydrolytic resistance, especially when exposed to alcoholic solvents and essences.
Innovation Solution
A method involving a sol-gel process using a solution of alkoxysilanes, surfactants, pigments, and citric acid is applied to the internal face of containers, forming a durable, opaque, and translucent barrier layer that is impermeable to chemical species and radiation, allowing for aesthetic marking without compromising mechanical or thermal resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If an outer covering is applied to the bottle, then aesthetic requirements are met, but the covering becomes fragile and liable to be damaged or torn off
Solution Approach 1:
Instead of applying the aesthetic coating to the outer surface of the bottle, the invention inverts the approach by applying the sol-gel coating to the inner surface of the bottle. This internal coating is then protected from external shocks and scratches, resolving the fragility issue while maintaining aesthetic appearance and allowing functionalization with colorants and UV filters.
2Shape
If internal marking is performed by coloring, then aesthetic requirements are met and protection from external damage is provided, but additional potentially harmful elements are introduced directly into the bottle
Solution Approach 1:
The invention changes the chemical parameters of the coating system by using sol-gel chemistry with controlled hydrolysis and condensation reactions. By adjusting pH, water content, and catalyst concentration, the process creates a neutral or slightly basic final coating that does not release harmful elements, unlike traditional acid-based coatings. The coating can be functionalized with colorants and UV filters without compromising neutrality.
Solution Approach 2:
The invention creates a composite material system combining the sol-gel derived glassy matrix with incorporated colorants and UV filters. This composite approach allows aesthetic functionalization while the glassy matrix provides barrier properties and chemical inertness, preventing release of harmful elements into the contained product.
3Ease of manufacture
If conventional sol-gel methods are used with acids such as acetic acid or hydrochloric acid, then coating formation is achieved, but residual acidity remains which can modify the olfactory perception of perfumes
Solution Approach 1:
The invention fundamentally changes the pH parameter throughout the coating process. By using excess water and controlled hydrolysis, the system evolves from initially acidic conditions through a neutral phase to a slightly basic final state. This parameter evolution ensures that the final coating has neutral or slightly basic pH, eliminating residual acidity that would affect perfume olfactory perception while maintaining effective coating formation.
4Ease of manufacture
If conventional sol-gel methods are used, then coating is formed, but the coating is too porous and does not provide sufficient hydrolytic resistance or barrier function
Solution Approach 1:
The invention optimizes several parameters simultaneously: using excess water to drive complete hydrolysis, controlling pH to favor condensation reactions, and adjusting precursor concentration and ratios. These parameter changes promote formation of a dense, cross-linked glassy matrix with minimal porosity, providing sufficient hydrolytic resistance and barrier function to prevent interaction between the contained product and the bottle, while still allowing easy manufacturing through simple coating and drying processes.
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 significantly enhances hydrolytic resistance, reduces ion release, and maintains aesthetic quality over time, ensuring a neutral and impermeable barrier that meets the requirements for long-term storage of perfumes and cosmetics without additional treatments.
Implementation Method 1
forming a solution containing at least one solvent, water, at least one complexing molecular precursor from the family of alkoxysilanes, at least one surfactant, at least one pigment and/or dye and citric acid as catalyst, applies the solution thus complexed in a uniform manner to at least part of the internal face of the container, the solution being in the process of hydrolysis and condensation
Implementation Method 2
the solution being in the process of hydrolysis and condensation, and the solution thus applied is dried at a determined drying temperature to form on said internal face said opaque, translucent barrier layer
Implementation Method 3
the solution thus applied is dried at a determined drying temperature to form on said internal face said opaque, translucent barrier layer
Data Source
Figure 1
Figure 2~3
Figure 4A~4B
AI summary
The invention relates to a method for producing a neutral barrier layer for coating the inner surface of a receptacle for holding products that are biocompatible for humans and/or animals, and to the receptacle obtained by said method. According to the invention, a solution is formed that contains at least one solvent, water, at least one complexing molecular alkoxysilane precursor, at least one surfactant, at least one pigment and/or coloring agent, and a catalytic acid, the complexed solution, which is undergoing hydrolysis and condensation, is homogeneously applied to at least one portion of the inner surface of the receptacle, the applied solution is dried at a specific drying temperature such that a layer is formed which is opaque, translucid and/or forms a particular pattern, and the receptacle is conveyed away, stored and filled with the product.