A device for producing LCP thin film liquid crystal materials specifically for 5G communication, involving a shared blown film production equipment for liquid crystal polymer films and TRX adhesive films. The blown film on blown method is used to solve the problem of directional instability caused by the stretching method on the market. The present utility invention belongs to the preparation of new material polymer composite films, which have the characteristics of high mechanical strength, uniform longitudinal and transverse tensile strength, and good bending resistance. It can be widely used in high-frequency and high-speed copper-clad laminates, solar cell backboards, wireless charging insulation sheets, 5G mobile phone antennas, camera soft boards, laptop transmission lines, smart watch antennas and other fields; The TPX film produced synchronously has the characteristics of good peel strength, good flexibility, and high tensile strength. It can be used as a barrier film for copper-clad laminates, breaking the equipment blockade that has been monopolized by Europe, America, South Korea, and Japan. Due to LCP material, it has been broken through by domestic polymer material enterprises and has been mass-produced and put into production, replacing materials from the United States and Japan.
LCP material is a high-performance functional engineering plastic, Liquid Crystal Polymer (LCP), which was developed in the United States in the 1970s. Its structure is composed of rigid molecular chains and can exhibit both liquid fluidity and crystal physical anisotropy under certain physical conditions. Liquid crystal polymer has high strength, high modulus, outstanding heat resistance, extremely small coefficient of linear expansion, excellent flame resistance, electrical insulation, chemical corrosion resistance, weather aging resistance and microwave permeability, as well as excellent molding and processing properties. At the same time, liquid crystal polymer has a small dielectric property at high frequencies
Constant and dielectric loss, especially suitable for antenna substrates in 5G millimeter waves. LCP film has the characteristics of low dielectric constant, low dielectric loss, low water absorption, and stable performance, making it an ideal 5G high-frequency and high-speed FCCL substrate.
The application of LCP from resin material to the final mobile phone antenna module requires the following steps: LCP resin film flex.
FCCL - Flexible Circuit Board FPC - Antenna Module. LCP resin is processed to obtain LCP film, which is then copper-clad by FCCL manufacturers to obtain FCCL. Soft board companies then process FCCL into FPC. The blown film method in existing technology still has the following shortcomings when preparing LCP film from LCP resin:
The blown film method in the existing technology is used to prepare LCP film due to the compressed air injected into the tube blank during the implementation of the tube blank.
When further expanding, it is difficult to limit the shape of the expanded tube blank, which can easily cause wrinkles and sticking of the formed LCP film.
In the case of uneven attachment, due to the obvious rigid molecular chain structure of LCP, it still has a crystal structure in the molten state and has obvious formability in the direction of force, resulting in significant directional differences in the longitudinal and transverse directions. The processing difficulty of the film is extremely high. The present utility invention uses an upward blowing method for bi-directional stretching and expansion to solve the above process drawbacks. It adopts a three-layer co extrusion composite process, with an outer layer of TRX, a middle layer of LCP, and an inner layer of TRX. After winding, the inner and outer layers of TRX film are peeled off, and finally LCP material is obtained.
The equipment structure is as follows:
S0- Three extruders are placed in a T-shape below the bottom of the frame, which is a frame tower structure with (columns, platforms, handrails, guardrails, stairs). The extruders are composed of (barrel screws, weighing hoppers, reducers, drive motors, screen changers, heaters, cooling fans);
S1 mold adopts a central spiral+stacking+IBC internal circulation structure, consisting of a heater, splitter, and internal circulation device. The internal air outlet eliminates the hot air inside the film bubble, and the internal air inlet injects external cooling air, thereby improving the cooling and shaping speed of the film bubble, increasing extrusion yield and film bubble transparency, glossiness, and mechanical strength. As LCP material requires a temperature of about 350 degrees to plasticize, conventional blown film cooling method cannot be used. IBC internal circulation method is adopted to help improve material orientation and processing performance. The mold uses special material forging and tempering, with good rigidity and no deformation;
S2- The air ring adopts automatic adjustment, and the heating method adjusts the thickness deviation of the film. It is equipped with heating rods, air duct diversion slots, and air chambers;
S3- The stable foam rack has electric lifting and electric telescopic diameter function, equipped with T-shaped screw, nut, guide roller, sprocket, chain, and drive motor;
The S4 thickness gauge adopts non-contact 360 degree center scanning measurement. Due to the adhesive properties of TRX material at high temperatures, using a contact type will cause measurement errors in the sensor. It is equipped with a conductive ring, wireless WLAN, rotating disk, and scanning bracket;
S5 herringbone board has electric opening and closing function, and the surface of the guide roller is sprayed with PTFE to reduce film adhesion and friction;
S6- The upper traction rotating part adopts a horizontal structure, equipped with a rotating gear plate, traction device, fan-shaped straight tooth mechanism, air flotation cooling roller, air pump, drive motor, flattening rod, and support platform;
S7- The longitudinal stretching part of the heat treatment is equipped with a steel rod, a driving motor, a support platform, and rotating interfaces at both ends of the steel rod, which are connected to the circulating heating of thermal oil;
The S7 edge correction machine has the function of automatically tracking and identifying material edge errors, consisting of (ultrasonic sensor, servo cylinder, guide wheel, bracket, guide roller, flattening rod);
S8 traction device, equipped with a slitting knife, tension sensor, rubber stick, steel stick, drive motor, and reducer;
S9- Dual station center friction winding part, AB winding is independently placed, with fully automatic mechanical arm lifting, threading, unloading, and cutting functions;
S10- Electrical control cabinet for thickness gauge and auxiliary control cabinet for unit, placed on the ground for easy movement and maintenance;
S11- Unit heating control cabinet, air cooler circulation device, placed on the side rack platform to save floor space;
The process flow is as follows:
1. Put different grades of LCP, TRX resin raw materials, functional masterbatch and additives into three extruder hoppers, with TRX placed in the inner and outer layers and LCP placed in the middle layer. After passing through a weighing vector device, they are accurately fed into the heating material cylinder screw according to the set proportion. The screw is driven by a driving motor to rotate, and the solid raw materials are heated and plasticized into a solution, which enters the composite mold to form a circular film embryo.
2. Multiple air inlet holes are distributed at the bottom of the mold, and two blowers are used to inject and remove compressed air, which enters the interior of the film blank for 3-10 times horizontal inflation. When more air is added, the diameter of the film blank increases, and vice versa. The diameter of the film blank increases, the width of the film becomes wider, and vice versa. The width of the film bubble is controlled by the cold and hot exchange cycle of two external blowers. Three ultrasonic ranging sensor signals are collected, and after PLC module system calculation, the frequency converter is automatically controlled to ultimately control the fan speed and synchronously closed-loop control the air circulation flow inside the film bubble.
3. The membrane embryo vertically enters the air ring, stabilizes the bubble holder, uses a thickness gauge, cools and shapes it, measures the thickness, and enters the herringbone board to flatten it into a sheet-like substrate. The thickness gauge measures the circumferential thickness deviation of the membrane bubble and feeds it back to the control system. After calculation by the CPU and acquisition card, the power of the heating rod inside the air ring is controlled to effectively automatically control the uniformity of the membrane bubble thickness.
4. The sheet substrate enters the first traction and passes through a horizontal rotating mechanism, intersecting in both forward and reverse directions, changing the lateral fixed position of the film bubble, improving the surface of the film bubble, and preventing bursting and bagging phenomena.
5. After the sheet is pulled out from the first track, it enters the longitudinal stretching section, where S-shaped multi sticks are inserted and stretched 3-10 times longitudinally. Finally, it enters the winding and pulling section for edge breaking and separation, forming a single-layer substrate, and then enters the winding and coiling cylindrical substrate.
6. Thickness gauge - installed above the stable bubble holder, rotating along the circumference of the rotating frame, for thin film scanning measurement. The measurement method is divided into non-contact capacitive measurement.
7. When the film bubble enters the winding part, it can be cut online according to the specifications and size requirements of the film. The winding machine is equipped with a mechanical arm for automatic cutting and material replacement, and has a (center+friction+gap) control mode function.
8. This device has the advantages of humanization, high degree of automation, convenient operation, and high cost-effectiveness.
Editor:Sichuan Jinzhongde Science and Technology Research Institute
