Patent Analysis of Perfluoropolyether and Its Derivatives!

Perfluoropolyether is a polymer or oligomer that is a colorless, odorless, and transparent oily liquid at room temperature. Its molecular structure only contains three elements: C, F, and O. It has many excellent properties, such as chemical inertness, thermal oxidation stability, compatibility, flame resistance, and radiation resistance, and is an important organic fluorine chemical.

The related products prepared from perfluoropolyether are widely used in fields such as aerospace, electronics, machinery, textiles, and heat transfer. Through the analysis of perfluoropolyether patents and the application of perfluoropolyether surfactants, the development history of perfluoropolyether was summarized, and the application of downstream perfluoropolyether surfactants was briefly explained.

The data sources used in this patent analysis are the Winter World Patent Index Database (DWPI), the World Patent Abstracts Database (SIP0ABS), and the China Patent Abstracts Database (CNABS). The search is conducted using keywords combined with classification numbers. Based on patent application data related to perfluoropolyether and its derivatives, statistical analysis is conducted from application trends, key applicants, and other aspects, Provide certain technical or information support for domestic fluorine chemical research enterprises or units.

1. Analysis of global patent application status

1.1 Patent Application Trends

Figure 1 shows the global trend of patent applications for perfluoropolyether.

From Figure 1, it can be seen that there were relatively few patent applications for perfluoropolyether from 1960 to 1980, and the research on perfluoropolyether has been in the early development stage; From 1980 to 2011, the number of patent applications for perfluoropolyether gradually increased, entering a period of technological accumulation and application development; Thanks to the rapid development of materials science, electronic information technology, optoelectronic science, and biotechnology, the number of patent applications for perfluoropolyether has rapidly increased since 2012, reaching 351 in 2018. However, the number of applications has gradually decreased. However, due to the lag in patent application disclosure, there will be more patent disclosures in the future. Therefore, after 2021, it does not represent the actual trend. Overall, it can be seen that the technology in this field is still in a prosperous period, and there is significant development space for perfluoropolyether and its related technologies, products, and applications worldwide.

1.2 Analysis of Technology Source Countries

Figure 2 shows the global ranking of key applicants for perfluoropolyether patents.

From Figure 2, it can be seen that the top 10 applicants for patent applications are Shin Yue Chemical (Japan), Solvay (Italy), Sony (Japan), 3M Company (USA), Daikin Corporation (Japan), Komo (USA), Hitachi Corporation (Japan), Asako AGC (Japan), Showa Corporation (Japan), and Panasonic Electric Appliances (Japan). The above applicants have a large number of patent applications, involving well-known fluorine chemical enterprises. They attach great importance to patent reserves, covering various aspects of upstream and downstream industrial products, technology, and applications. According to the analysis of key applicants for perfluoropolyether patents, they mainly come from countries with highly developed fluorine chemical industries such as Japan, the United States, and Italy, but their main patents have been laid out in China.

As the main source countries of technology, Japan, the United States, and the European Union account for over 50% of the total application volume, and they are also increasingly valuing the Chinese market. At the same time, domestic fluorine chemical enterprises such as Zhonghao Chenguang, PetroChina, Hunan Nonferrous Metals, Zhonghua Lantian, Zhejiang Juhua, Tianjin Changlu, and Longyan Sikang have also conducted relevant patent layouts. However, due to the low level of technological development, short time for industrial development and market application development, the number of patent applications is relatively at a disadvantage. In addition to traditional domestic fluorine chemical enterprises, some downstream application fields have also conducted related series and patent layouts for perfluoropolyether and its derivatives, such as OPPO Guangdong Mobile Communication, BOE, Tianjin Rijin Technology, Guangzhou Yongnuo Medical, and China Electric Power Research Institute.

1.3 Patent Technology Analysis of Perfluoropolyether Main Chain

There are two main production methods for perfluoropolyether main chains, namely the anionic polymerization of perfluorinated or fluorinated epoxides and the photooxidation of perfluorinated olefins. According to different polymerization methods and monomers, perfluoropolyether with different molecular structures can be polymerized, mainly consisting of four types: K-type, Y-type, Z-type, and D-type. Among them, K-type and D-type are prepared through anionic polymerization, while Y-type and Z-type are formed through photocatalytic polymerization using perfluoroalkenes as raw materials.

Taking the anionic polymerization method of hexafluoroepoxypropane as an example, using hexafluoroepoxypropane as the raw material and fluorine ions as the catalyst in an aprotic solvent, K-type perfluoroepoxypropane oligomers containing acyl fluorine end groups can be obtained. In photooxidative polymerization, perfluoropolyether with different structures is obtained by using tetrafluoroethylene or a mixture of tetrafluoroethylene and hexafluoropropene as raw materials, and being illuminated with oxygen at low temperatures. Y-type and Z-type perfluoropolyether only have different raw materials, resulting in different product structures. In addition to the acyl fluoride end group, there are also peroxide groups on the main chain.

The crude product is heated or illuminated to eliminate unstable peroxide groups, and then the end groups are stabilized with fluorine gas. The relative molecular weight distribution of perfluoropolyether obtained by the two methods is wide, and the perfluoropolyether oil obtained after the end group acyl fluoride is capped as the base oil. After compounding with certain additives, it can meet the requirements of high-temperature and high-load applications in the mechanical and automotive industries. The high stability and good wear resistance of perfluoropolyether oil make it a lubricant for long service cycles and harsh operating conditions.

In terms of application, perfluoropolyether has a wide liquid temperature range, low evaporation, high static viscosity, very low vapor pressure, low flow temperature, and good high-pressure lubrication performance, making it widely used in the aerospace industry; In semiconductor industries such as oxygen production, highly corrosive working conditions, and plasma etching, perfluoropolyether is used as lubricating oil or compressor oil for vacuum mechanical pumps; In the mechanical industry, perfluoropolyether is often used as a lubricant for plastic bearings, metal bearings, conveyor belts, papermaking, and textile machinery; In the nuclear industry, perfluoropolyether is used as a concentrated ultra centrifugal bearing lubricant for uranium hexafluoride; Perfluoropolyether can also be used for lubrication of magnetic media such as hard drives and magnetic tapes; Perfluoropolyether is also a good heat transfer medium.

2. Analysis of Patent Application Status for Fluoropolyether Derivatives

After 2010, the research hotspot of perfluoropolyether has shifted to downstream derivatives of perfluoropolyether and their applications. This is because perfluoropolyether has better chain flexibility compared to polytetrafluoroethylene and does not produce polymer crystalline forms like polytetrafluoroethylene. However, it retains excellent properties such as high-temperature stability, radiation resistance, and chemical corrosion resistance of the carbon fluorine chain segment, and this chain segment has good hydrophobicity and oil repellency, which has wide and important applications in many fields. The relevant application patents of downstream derivatives of perfluoropolyether are presented below.

2.1 Perfluoropolyether surfactants

Perfluoropolyether surfactants have excellent properties that other non fluorinated surfactants do not possess, and can reduce the surface tension of aqueous solutions to very low levels at very low concentrations. Perfluoropolyether surfactants can significantly reduce the surface tension of solutions at extremely low concentrations, exhibit high thermodynamic and chemical stability, and excellent compatibility. Based on its excellent performance, fluorocarbon surfactants are widely used in the polymerization of fluoropolymers, coating dispersion, oil displacement W, fire extinguishing, PCR gene detection, textile, leather, and papermaking fields.

Patent CN201710505403.5 discloses a perfluoropolyether surfactant for extinguishing hydrocarbon organic substances. One end of the perfluoropolyether surfactant is a hydrophilic amine substance. The foam formed in extinguishing can be well spread on the oil surface to form a water film, which can isolate the air, reduce the temperature of the oil surface, and thus play a role in rapid extinguishing.

The addition of fluorine-containing surfactant in the extinguishing agent greatly reduces the surface tension of water. The water spreads rapidly, and the foam also spreads rapidly, which is equivalent to a two layer diaphragm. It can be used to extinguish fires caused by various non solution flammable and combustible liquids, including oil, and greatly improve the efficiency and capacity of fire water. In addition, patents for perfluoropolyether based surfactants such as perfluoropolyether sulfonate, perfluoropolyether quaternary ammonium salt, perfluoropolyether alcohol hydroxyl, and perfluoropolyether polyethylene glycol have also been disclosed.

Due to the adjustability of the main chain synthesis of perfluoropolyether (CN111087604A), relevant enterprises have made patent layouts for single head and single tail surfactants, double head and single tail surfactants, double head and double tail surfactants ("head" refers to hydrophilic groups or chain segments, "tail" refers to hydrophobic groups or chain segments), as well as star and block type perfluoropolyether surfactants.

2.2 Perfluoropolyether fluorinated silane

Perfluoropolyether segments have extremely low surface energy, as well as hydrophobicity and hydrophobicity. However, its polarity is low, and its interaction with materials such as glass, ceramics, metals, and organic materials is low, resulting in poor material adhesion. Especially when applied to coatings, the excellent performance of the surface is often lost after repeated cleaning or wiping, making it difficult to directly apply. When fluorinated segments encounter silane, the properties of the two materials are organically unified. Especially for perfluoropolyether segments, their end groups are often functional groups with stronger processing plasticity, and they can form various stable chemical bonds with silane. Fluorinated silane forms a stable structure by cross-linking on the surface of the material, with excellent wear resistance, while retaining the hydrophobic, oil repellent, and anti fouling properties of perfluoropolyether, and also has good transparency.

Dow Corning and Daikin have disclosed a method for synthesizing perfluoropolyether silane and its application in material surface treatment. It uses reducing agents such as NaBH4 to first reduce perfluoropolyether with acyl fluorine as the end group to perfluoropolyether alcohol, then undergoes allylation reaction with allyl bromide to obtain allylated perfluoropolyether, and finally undergoes methylsilylation reaction with trichlorosilane to prepare perfluoropolyether type silane. The fluorinated silane forms a thin layer on the surface of materials such as glass, organic materials, and stone, which has good wear resistance on the one hand and excellent optical projection on the other hand.

In addition, 3M Company, Corning Company, Saint Gobain Glass Company of France, BOE, Dow Chemical, Bayer Chemical, Longyan Sikang New Materials and other companies have all carried out patent layouts for perfluoropolyether fluorinated silane, preparing fluorinated silane products with rich structures, diverse functions, and wide application fields.

2.3 Perfluoropolyether monomer

Perfluorinated polyether monomers are mainly divided into two categories: perfluorinated monomers and partially fluorinated monomers. The preparation of perfluorinated monomers refers to the decarboxylation of perfluorinated polyether to prepare perfluorinated polyether alkoxyvinyl ether. As a comonomer in fluorinated rubber and perfluorinated ion exchange membranes, it can disrupt polymer crystallization, effectively reduce the glass transition temperature of the material, and improve its flexibility. Some fluorinated monomers are mainly prepared by modifying the end groups of perfluoropolyether. Typical monomers include epoxy functionalized perfluoropolyether, perfluoropolyether methacrylate monomers, perfluoropolyether acrylate monomers, perfluoropolyether isocyanate monomers, etc.

Sichuan Chenguang Boda has disclosed a UV curable coating containing perfluoropolyether modification additives. It is introduced into the polymer using perfluoropolyether acrylate as a comonomer, effectively reducing the surface free energy of the material, endowing the coating with good hydrophobic and oil repellent properties, enhancing the oil stain resistance and solvent resistance of the coating, and having better environmental friendliness compared to polymers with perfluorooctanoxy groups. Some fluorinated monomers are mainly copolymerized with monomers containing hydrocarbons. The introduction of fluorinated monomers can also improve the transparency of the material and significantly improve its electrical insulation performance.

3. Conclusion

Perfluoropolyether was first used in the nuclear industry, and its excellent chemical stability, high and low temperature resistance, and excellent electrochemical performance have been widely used in civil fields such as aerospace, machinery, and electronics, with related technologies and applications tending to stabilize. Products such as surfactants, fluorinated silanes, and polymeric monomers based on perfluoropolyether main chains are being sought after by numerous applicants both domestically and internationally, driving the rapid development of fluoropolymers and bringing new performance experiences to the field of materials science.