1. LCP: Excellent performance and wide application, the supply is concentrated in Japan and the United States
1.1 Definition and classification of LCP
The special molecular structure of LCP material determines its excellent macroscopic properties. LCP (Liquid Crystal Polymer, liquid crystal polymer / polymer) is a fully aromatic liquid crystal polyester polymer material composed of a rigid polymer chain structure. Due to the particularity of the molecular structure, it has good vibration absorption characteristics, low dielectric properties, self-reinforcing effect, good chemical resistance and heat resistance, low melt viscosity, small linear expansion rate, small molding shrinkage rate, Excellent performance such as extinguishing and not easy to produce flash.
According to the conditions for forming liquid crystal, LCP can be divided into lyotropic liquid crystal (LLCP) and thermotropic liquid crystal (TLCP). Among them, LLCP can be dissolved in the solution and arranged in a certain order at a certain concentration, showing some crystal properties. According to this characteristic, LLCP is generally used as fibers and coatings; while TLCP enters the liquid crystal state when it is thermally melted, with excellent In addition to being used as high-performance fibers, it can also form various products through processing methods such as injection molding and extrusion, which has a wider application range than LLCP. Therefore, TLCP has been used in electronic information and aerospace in just a few decades. , Automotive, machinery, chemical and medical fields have been important applications, known as "super engineering materials." Based on this, we mainly discuss TLCP in this article.
Generally, according to different heat resistance, we divide LCP into I, II and III types, which correspond to high, medium and low heat resistance, respectively. Type II is the preferred film matrix resin for antenna materials. 1) Type I LCP is mainly polymerized by monomers such as p-hydroxybenzoic acid, biphenyldiol / hydroquinone, terephthalic acid / isophthalic acid, etc. Due to its more rigid structure benzene ring, Therefore, it has good heat resistance and is widely used in connectors and other electrical and electronic fields. The representative products are mainly Sumitomo Chemical's SumikaSuper and Solvay's Xydar. 2) Type II LCP is mainly polymerized by p-hydroxybenzoic acid and 6-hydroxy-2-naphthoic acid as monomers. Its heat resistance lower than Type I brings better processing performance. It is to prepare LCP film ( The best matrix resin for antenna), the technology is mainly mastered by Polyplastics and Celanese (Ticona). 3) Type III LCP Because the molecular structure contains PET, the addition of its flexible ester group further reduces the heat resistance of the material. The representative products are mainly Rodrun of Japan Unicka and Novaccurate of Toray of Japan.
1.2 Development history of LCP materials
After the integration of the global LCP material industry, the US and Japanese companies are the main ones. In recent years, Chinese companies have gradually entered the field of resin production. LCP as a product on the plastic stage can be traced back to the earliest Carborundum company in the United States to sell the polyparaben produced on the market under the trade name Ekono1. Later, with historical changes and the gradual integration of companies in the industry, currently the most well-known LCP resin material manufacturers globally include Celanese (Ticona), Polyplastics Japan, Sumitomo Japan, Toray Japan and other companies, among which Celanese acquired DuPont`s LCP business in 2011 and is currently the world`s largest. In recent years, Chinese companies have also gradually cut into LCP resin production. Representative companies include GZJF Technology, SZWT, SHPL and NBJJ.
1.3 The supply of LCP resin is mainly concentrated in the United States and Japan, and the demand in traditional fields has maintained rapid growth
From the specific data, global LCP resin production is mainly concentrated in the United States and Japan, of which Celanese, Polyplastics and Sumitomo of Japan are the major global suppliers, and the production capacity of the three accounts for 63%. After Celanese acquired DuPont's original LCP business, the global production capacity reached 22,000 tons, accounting for nearly 30%; while Celanese, Polyplastics, and Sumitomo accounted for 63% of the production capacity, and the industry concentration was high. At present, the representative enterprises in China with large-scale mass production capacity are GZJF Technology, SZWT, SHPL and NBJJ, TWCC, etc.
In recent years, the demand for LCP has been growing rapidly, and its applications are mainly concentrated in the electrical and electronic fields. In terms of total volume, according to the Foresight Industry Research Institute, the global LCP demand in 2018 was 70,000 tons, + 7.7% year-on-year, of which the 2014-2018 annual compound growth rate of demand was 9.8%, showing a rapid growth trend. From the structural point of view, LCP is widely used, but most of it is concentrated in the field of electronics and electronics. Its application in this field is mainly used as a connector on computers and communication equipment. This is because LCP can meet the connector's high temperature welding and oil resistance. Stability and other excellent performance in extreme environments such as heat resistance and radiation resistance
The traditional application areas of LCP are more extensive. Among them, LCP as engineering plastics can be used as connectors in electronic devices such as mobile phones and computers, car headlight housings, high-temperature baking trays and cake molds; as fibers can be used in spacecraft airbags, tire reinforcements, Cut gloves and optical fibers; made of alloys can be used for corrosion-resistant chemical pumps, automobile brake pads and high-end audio pickups.
2. LCP is expected to become the core film material for 5G antennas, with a long-term market space of up to 23.3 billion yuan
2.1 The 5G era puts forward higher requirements for the circuit board substrate in the antenna module
3GPP defines the frequency range of 5G, which is divided into Sub-6G and millimeter wave. According to the definition of 3GPP, 5G NR includes two large spectrum ranges, namely FR1 (corresponding to 450MHz to 6000MHz, commonly referred to as Sub-6G) and FR2 (24250MHz to 52600MHz). Classified by frequency band, FR1 belongs to centimeter wave, while FR2 belongs to millimeter wave. (Wavelength = speed of light / frequency, ie the higher the frequency, the shorter the wavelength).
Most countries and regions except the US give priority to the development of the Sub-6G frequency band, and then gradually transition to millimeter wave. According to the situation of various countries, China, Europe and other places mainly develop Sub-6G first, and then gradually transition to millimeter wave; while the United States directly chose the millimeter wave route because of the military spectrum is Sub-6G, but it is worth noting that Recently, the US Federal Communications Commission (FCC) decided to spend 9.7 billion US dollars to accelerate the repurchase of 3.7GHz-4.2GHz spectrum and use it for 5G network construction. This news may mean that the United States may re-plan 5G layout, and the center of gravity is expected to be transferred in the early stage To Sub-6G.
Due to the characteristics of 5G high speed and high frequency, in order to ensure reliability and reduce signal loss during transmission, 5G communication has higher requirements on the dielectric constant and dielectric loss factor of antenna materials. At present, the flexible circuit board (FPC) substrate used in mobile phone antennas in the 4G era is mainly polyimide (PI), which is a comprehensive consideration of PI its excellent mechanical strength, bending performance, continuous stability, heat resistance, insulation Features and other advantages. However, due to the high water absorption rate of the PI substrate, the dielectric constant (Dk) and dielectric loss factor (Df) are also large, especially for products with operating frequencies exceeding 10 GHz, so it is difficult to meet the requirements for antenna materials in the 5G era. .
There are currently two mainstream solutions: Modified PI (MPI) or LCP, where MPI has certain comprehensive advantages in Sub-6G, but with the advancement of 5G commercialization, the millimeter wave stage will still be dominated by LCP. In terms of transmission reliability, LCP> MPI> PI; in terms of moisture resistance, LCP> MPI> PI; but in terms of cost, the current LCP film is subject to product yield and film supply monopoly, with the highest cost and the lowest economy, while PI film is mature The application product has the lowest cost, but it cannot be used for antenna transmission in the 5G era. The modified MPI can resist the LCP in the Sub-6G stage, but the loss in the millimeter wave band is further widened than the LCP, so the LCP will still be the main antenna film in the millimeter wave stage.
2.2 Low dielectric loss and extremely low water absorption rate give LCP materials excellent signal transmission performance
Compared with PI, LCP can greatly reduce high-frequency transmission loss. According to Sumitomo Electric industrial data, compared with PI materials, the transmission loss is smaller at the frequency of 5GHz, and as the frequency is gradually increased, the loss reduction is further expanded.
The extremely low water absorption rate of LCP material is destined to become the core film material for 5G antenna transmission. Compared with PI, in addition to LCP having a lower dielectric loss factor Df, another important indicator is that its water absorption rate is extremely low, that is, it will hardly absorb moisture, so the loss-frequency curve of its substrate migrates before and after moisture absorption. Not obvious. On the contrary, the loss-frequency curve of the PI substrate is more obvious before and after moisture absorption, and the transmission loss is larger.
2.3 Modified PI (ie MPI) has the ability to compete with LCP in the Sub-6G band
From the performance point of view, MPI does not lose LCP during the Sub-6G stage, and the supply can be transferred from the original PI manufacturer. Modified PI (that is, MPI) stands for Modified PI, which is prepared by introducing fluorine atoms, siloxane and other methods. The dielectric constant and dielectric loss factor of MPI are better than PI and close to LCP, and the water absorption rate is much better than PI, but it is still not as good as LCP. According to Taiwan ’s Taimide data, in the Sub-6G frequency band, the transmission loss difference between MPI material and LCP material is not obvious. The performance of MPI in the 6-15GHz frequency band is only slightly lower than that of LCP, which can meet the 5G era antenna transmission. Requirements, but in the higher frequency bands above 15GHz, the gap between MPI materials and LCP materials is gradually obvious and widening. It should be noted that the loss curve of Taimide's MPI product LKA-025 in the 25-30GHz band is almost the same as that of LCP, but the extremely low water absorption rate of LCP is still destined to MPI cannot replace LCP as the circuit board base for antennas in the millimeter wave stage material.
2.4 The global LCP film market space for 5G antennas can reach 23.3 billion yuan in the future
In practical applications, Apple ’s newly released iPhone X at the end of 2017 applied LCP material to the antenna for the first time, aiming to improve the antenna ’s high-frequency and high-speed performance while reducing space occupation. According to industry disassembly reports such as electronic enthusiasts, the iPhone X uses two sets of LCP antennas, which are the upper antenna and the lower antenna. In addition, the upper and lower antennas still use one set of PI antennas. There are two sets of LCP and PI antennas in the entire mobile phone. In 2018, the iPhone XS / XS Max / XR have 3/3/2 groups of LCP antennas, but in the new series of 2019, because the series still does not support 5G and is subject to factors such as cost and suppliers, it has reduced The number of LCP antennas is replaced by MPI antennas. Apple's move made the market believe that in the Sub-6G frequency band, MPI is a substitute for LCP before transitioning to the 5G millimeter wave band due to the large number of suppliers, availability and better economy. However, in the long run, as the commercialization of 5G gradually matures and enters the millimeter wave band, the production cost and yield bottleneck of the stacked LCP materials will be further reduced, and LCP will eventually be the final destination of 5G antenna materials.
Measurement of LCP film usage for stand-alone antenna: Taking iPhone X as an example, according to Iparts Expert data, the size of the lower antenna is 9cm * 7cm, and the size of the upper antenna is 6cm * 4cm. The total area of LCP film consumables is 174cm2. The single-layer LCP film thickness of 25 μm and the LCP material density of 1.61 g / cm3 (take a model of Polyplastics) from the double-layer board structure can be used to calculate the volume of the antenna LCP film used for a single machine is 0.435 cm3 and the mass is 0.70 g.
Price of LCP film for antenna: LCP film for antenna is currently exclusively supplied by Murata on the market but mainly for self-use. We believe that its price does not have much reference for the future situation after heavy volume (resin manufacturers break the barriers to film production , Improve the process to improve the yield, etc.). According to our industry research, the current LCP film is distributed at a price of 300-1600 yuan / square meter according to grade, and the price we selected for space calculation is 300 yuan / square meter, mainly based on the increase in future production capacity and yield bottlenecks to drive penetration and suppliers The assumption that an increase in the number leads to a gradual price drop.
The market space for LCP films for antennas is expected to reach 23.3 billion: According to Counterpoint data, the total global smartphone shipments in 2019 will be 1.486 billion units. We can use this as a base to calculate and calculate that when the LCP antenna penetration rate reaches 100%, if the 6 antennas of each mobile phone are LCP antennas, the market space for LCP films for long-term antennas can reach 23.3 billion yuan; in addition, the measured films The long-term space for high-grade resin is 940 million yuan.