Oil repellent: the hero behind the oil repellency of materials

In many scenarios of daily life and industrial production, the oil resistance of materials is crucial. Whether it is to prevent kitchen utensils from being attached with oil stains or to prevent packaging materials from being penetrated by grease, oil repellents play an indispensable role.

1. Working principle of oil repellent

Oil repellent can change the properties of the material surface, reduce the affinity between the material surface and oil, and thus achieve oil repellency. Its core mechanism of action is mainly based on the following two aspects:

1) Reduce surface energy: 

From a molecular level, oil droplets tend to spread and adhere to the surface of materials with higher surface energy. Oil repellent molecules have a special structure, which can be arranged in a directional manner on the surface of the material, with low surface energy groups facing outward, reducing the free energy of the material surface. When the surface energy of the material is lower than the surface tension of the oil, the oil droplets will remain spherical on the surface of the material, making it difficult to spread and adhere, just like water droplets rolling on lotus leaves without wetting the lotus leaves, greatly reducing the contact area between the oil and the material, and achieving oil repellency.

2) Forming a barrier layer:

 Some oil repellents will form a continuous and dense microscopic barrier layer on the surface of the material. This barrier layer is like a shield, blocking oil molecules from penetrating into the material. Some polymer oil repellents, through cross-linking or chemical reactions with the surface of the material, are tightly bound to the surface of the material, effectively preventing the invasion of oil substances.

2. Application of oil-resistant agents in different fields

1) Packaging industry

Food packaging: Food packaging materials need to have good oil-resistant properties to prevent oily foods, such as fried foods, meat, etc. from penetrating oil, keep the packaging appearance clean, and avoid oil leakage from contaminating other items. Oil-resistant agents are widely used in paper food packaging, such as disposable lunch boxes, food packaging bags, etc. It not only ensures that the packaging material is not penetrated when it comes into contact with oil, but also ensures the quality and safety of food, and meets the hygienic standards for food packaging.

Industrial product packaging: For the packaging of some oil-containing parts or oily products, oil-resistant packaging materials are also required. Oil-resistant agents enable packaging materials to resist the erosion of industrial oils such as lubricating oil and hydraulic oil, protect products from oil contamination during transportation and storage, and also maintain the integrity of packaging materials to prevent packaging damage caused by oil penetration.

2) Textile industry

Functional clothing: Outdoor clothing, work clothes, etc. often need to have oil-resistant functions. For example, chef clothes, auto repair work clothes, etc., are very easy to come into contact with oil in the working environment. By treating the fabric with a finishing agent containing an oil-repellent agent, an oil-repellent layer can be formed on the fabric surface. When oil stains splash onto clothing, they will not immediately penetrate and adhere, but will form oil beads that roll off, making it easier to clean, keeping the clothing clean and tidy, and extending its service life.

Home textile products: Home textile products such as sofa covers and tablecloths also use oil-repellent agents. This can effectively prevent stains such as edible oil and cosmetic oil, reduce the frequency of cleaning, maintain the beauty of home textile products, and enhance the user experience.

3) Construction and decoration industry

Wall materials: The walls of places such as kitchens and restaurants are easily contaminated with oil stains. Adding an oil-repellent agent to the wall paint can form an oil-repellent surface on the wall. When oil stains contact the wall, it is not easy to adhere and is easy to clean. You only need to wipe it gently with a damp cloth to remove the oil stains, keep the wall clean, and avoid problems such as discoloration and damage to the wall caused by long-term accumulation of oil stains.

Floor materials: In the floor laying materials of some industrial plants and restaurant kitchens, oil-repellent agents can enhance the oil-repellent performance of the floor. Prevent the ground from being polluted and eroded by lubricants, cooking oils, etc., maintain the ground's anti-slip properties and aesthetics, and reduce the risk of slipping accidents caused by oil pollution.

3. Types and characteristics of oil repellents

1) Organic fluorine oil repellents: 

This is a type of oil repellent with excellent performance, which has extremely low surface energy and can give materials excellent oil repellency. Organic fluorine oil repellents not only have good resistance to common animal and plant oils, but also have good oil repellency to some difficult-to-handle silicone oils. It has high chemical stability and strong weather resistance, and can maintain oil repellency for a long time under different environmental conditions. However, due to the particularity of the fluorine element, some organic fluorine oil repellents have poor degradation in the environment and may have certain environmental risks. In recent years, their use has been restricted by some environmental regulations.

2) Silicone oil repellents: 

Silicone oil repellents have good thermal stability and chemical stability. It can form a flexible and durable oil repellent film on the surface of the material, and has good resistance to a variety of oils. At the same time, silicone oil repellents have good compatibility with many materials and will not affect the physical properties of the material itself, such as flexibility and transparency. It is widely used in textile, leather and other industries, and can maintain the original feel and appearance of the material while improving the oil repellency.

3) Polymer oil repellents: Polymer oil repellents are usually composed of high molecular weight polymers, which form a dense oil repellent structure on the surface of the material through intermolecular interactions. This type of oil repellent can be molecularly designed and synthesized according to different needs, and has good customization. They are widely used in packaging materials, plastic products and other fields, and can effectively improve the oil resistance of materials. They are relatively low in cost and have advantages in some cost-sensitive application scenarios.

With its unique mechanism of action, oil repellents play a key role in many fields and bring many conveniences to our lives and industrial production. With the continuous advancement of science and technology and the increasing requirements for environmental protection, the research and development of more efficient and environmentally friendly oil repellents will become the future development direction to meet the higher demands of various industries for the oil resistance of materials.