April 02, 2024

In order to achieve "dryness", "waterproof and sweat-resistant" and "long-lasting makeup", film-forming agents play an indispensable role here.

1. What is a film former?

Film-forming agents are generally high molecular polymers.

According to the source and nature, it can be divided into silicone film-forming agents, acrylic resin film-forming agents, silicone acrylates, polyethylene copolymers, protein film-forming agents, copolymers of various hydrocarbons, etc.

In cosmetics, based on the different properties and characteristics of film-forming polymers, the products can be given moisturizing, sunscreen, waterproof and anti-sweat, and styling effects.

1) Film-forming agents in sunscreen

Assists in increasing SPF value, reducing the amount of physical sunscreen added; improving skin feel; waterproof and anti-sweat; wear-resistant; anti-migration

2) Film-forming agents in makeup

Quick-drying and styling of liquid foundation, mascara, eyeliner, etc.; helps disperse toner; improves gloss; waterproof and sweat-resistant; wear-resistant; anti-migration

3) Film-forming agents in cream masks

Moisturizing: After film formation, moisture loss can be prevented

Physical cleaning: After the peel-off mask is formed, when it is peeled off, it is helpful to adsorb and remove the gray layer and "dead skin" on the surface of the skin to achieve physical cleaning and exfoliation.

"Magical" silicone resin film-forming agent

Different polymers have different properties and characteristics.

Among them, silicone resin has good film-forming properties and lubricity. The film formed can provide a full texture, comfortable and smooth skin feel, is breathable and does not cause acne, so it is very popular among cosmetics manufacturers.

The summer foundation that firmly dominates the list, as the "mother of oily skin", is waterproof and sweat-resistant, and has long-lasting makeup. Launched a 24-hour base makeup campaign. This is due to the addition of a large amount of silicone film-forming agents in the formula, which makes the makeup long-lasting and comfortable and breathable.

What exactly is a silicone resin film-forming agent?

From a structural point of view, silicone resin film-forming agent is a polymer with a three-dimensional network structure composed of silicon atoms and oxygen atoms as basic elements.

To understand the structure clearly, you must first understand the concept of "structural unit".

There are four basic structural units of silicone resin film-forming agents (for convenience of description, the silicone chemistry community uses M, D, T, Q as abbreviations):

These structural units are the monomers that build silicone resin film-forming agents.

(It’s important to remember these structural units! They are the key to identifying the type of silicone resin)

According to different basic structures, silicone resin can be divided into two categories: [T-type silicone resin and MQ-type silicone resin].

Among them, T-type silicone resin has [polymethylsilsesquioxane] as its basic structure, while MQ-type silicone resin has [trimethylsiloxysilicate] as its basic structure.

Although the "structural units" seem simple and regular, the silicone resins they constitute are very complex and diverse, and their performance characteristics are also different accordingly. They are both called "trimethylsiloxysilicate" but they are so different.

Taking MQ resin as an example, we can know from the name that MQ resin is composed of two monomers, M and Q.

The INCI name of MQ resin is [trimethylsiloxysilicate]. The performance of this polymer is determined by its exact structure.

The ratio of M to Q groups is extremely important, which determines the structure of MQ resin and its application.

If the structure of MQ resin is abbreviated as MnQ, you can imagine that the simplest composition is the following M4Q structure (red is the M unit, blue is the Q unit):

Its molecular structure looks like this:

When the ratio of M to Q gradually decreases from 4:1, complex three-dimensional structure products can be obtained.

Note: MQ resin structure with M/Q<4

(Red is M unit, blue is Q unit)

The lower the M/Q, the closer the obtained product is to the crystal structure. For ease of use, these products are generally dissolved in solvents before use.

When M/Q is close to 4, it is easy to form a low-viscosity liquid resin, which is beneficial to improving the surface and giving better spreadability, dispersion and conditioning.

When M/Q is close to 1, it is easy to form a solid resin that can form a film, which is conducive to the spreading of toner/physical sunscreen agent and has waterproof, oil, and migration resistance properties.

Obviously, MQ resin has many "brothers and sisters" with the same father and mother (all composed of M and Q units) (different M/Q ratios, molecular weights, arrangements, etc.). Therefore, there are many different models under the same INCI name, with different use effects.

In addition, MQ resin has many "relatives" (different R groups are introduced on the M unit).

It is generally believed that MQ resin is a compact spheroid with a double-layer structure.

The core of the ball is a Q layer with higher density connected by Si-O-Si chains, and the shell is an M layer with lower density (R3SiO1/2). The R groups of MQ resin are all methyl groups.

The R on the spherical shell (M layer) is mainly methyl. When different R groups are introduced, many different types will be formed:

When all R are methyl groups, it is called methyl MQ resin, or MQ resin for short (the example given above);

When all R are phenyl, it is called phenyl MQ resin;

When part of R is phenyl (the rest is still methyl), it is called methylphenyl MQ resin;

There are also fluorine-containing MQ resin, vinyl MQ resin, etc.