Many brand customers may not realize that the mirror-like glass surface actually hides the challenge of ink adhesion.To solve the above problems and ensure that the brand logo and exquisite patterns can be presented on the skin care glass bottles in a durable and vivid manner, we must pre-treat the glass surface. The following are several methods commonly used in the industry:

1.Why is it difficult for ink to adhere to glass bottles of skin care products?

Glass is primarily composed of silicon dioxide (SiO₂), which has a unique structure: silicon atoms (Si) are primarily located within the glass, while oxygen atoms (O) are more exposed on the surface. This structure results in an extremely high surface energy, making the glass highly reactive and easily interacting with surrounding materials.

This structure has a high surface energy and is easily interacted with other substances. For example, when exposed to air, it combines with hydrogen in the air to form hydrophilic groups. These hydrophilic groups, OH (hydroxyl), float on the glass surface, making it difficult for ink to adhere. Alkali ions on the glass surface form Na-O bonds. These bonds are easily broken by air and water, making it difficult for ink to adhere.

2.Four surface treatment processes for skin care glass bottles

Fat sensitive treatment

Various siloxane coupling agents are coated on the glass surface to form lipid-sensitive groups, thereby increasing the affinity of the glass to ink.

Fat removal treatment

Before any treatment, ensuring the glass surface is absolutely clean is the first step. Grease and dust contaminated during production and transportation are the biggest enemies of ink. We usually use organic solvents such as acetone and methyl ethyl ketone for precision cleaning, or use efficient vapor degreasing process to completely remove all contaminants.

Strong acid treatment

In order to solve the problem of easy migration of alkali ions on the glass surface.By using strong acid solutions such as hydrofluoric acid and sulfuric acid to corrode the surface of the glass bottles of skin care products, the weak boundary layer and free alkali ions on the surface can be effectively removed, forming a microscopically rougher and more stable surface structure, thereby fundamentally improving the mechanical interlocking force and chemical bonding force of the ink.

Physical polishing

Light sandblasting with very fine abrasives or hydro-sanding with hydro-sandpaper can create countless tiny bumps and depressions on the glass surface at a microscopic level.Light sandblasting with fine powder abrasive or hydro-grinding with water-abrasive paper can remove surface attachments and improve ink affinity.