Overviewing common circuit board, PCB material selection will be a qualitative choice of products.

1. Consumption: regular
2. Industry: FR-4 tg-150
3. Premium medical equipments: FR-4 tg-170
4. Senior Aviation, oil: FR-4 TG- 250

The PCB cost sequence of the above plates is: S1141 < it180a < s1155 < s116. Of course, there are many types of FR-4 on the market. Among them, S1141 has the best performance in the FR-4 of ordinary TG; it180a has excellent performance in the FR-4 performance comparison of ordinary high Tg, which can replace s1170, s1000-2, FR406, pcl-370hr, n4000-6 and other plates.

In the production of epoxy resin copper clad laminate, FR-4 copper clad laminate has always maintained its dominant position. According to reports, the main reason is that this product has excellent comprehensive performance and flame retardancy, and has a better function price ratio, which is popular with users.

1) FR-4 resin glue

<1>In the epoxy resin copper clad laminate industry, FR-4 copper clad laminate has been produced for many years, and the formula of resin glue is basically the same.

<2> preparation method

·Dimethylformamide and glycol methyl ether are stirred and mixed to form a mixed solvent.

·Add dicyandiamide and stir to dissolve.

·Add epoxy resin and mix.

·Dimethylimidazole is pre dissolved in an appropriate amount of dimethylformamide, then added to the above materials, and then fully stirred.

·After 8 hours of storage (aging), meet technical requirements for sampling and testing

<3>technical requirements for resin glue

·Solid content 65% - 70%.

·Gel time (171 C) 200 ~ 250s.

2）Adhesive sheet

<1> manufacturing process

After uncoiling, the fiberglass cloth enters into the rubber groove through the guide roller. After impregnation, the resin content is controlled by the extruding roller, and then enters the oven. During the drying process, the volatile matters such as solvents are removed and the resin is in the semi curing state. After leaving the oven, cut according to the size requirements, and neatly stack on the storage rack. Adjust the gap of extrusion roller to control the resin content. Adjust the temperature, air volume and speed of oven in different temperature regions to control gel time and volatile matter content.

<2>detection method in the manufacturing process of the adhesive sheet, in order to ensure the quality, it is necessary to regularly detect the technical requirements. The test method is as follows: resin content

·At least 25 mm from the edge of the adhesive strip, cut 3 samples according to the width direction, left, middle and right. The sample size is 100mm × 100mm, and the diagonal is parallel to the longitude and latitude.

·Weigh one by one (W1), accurate to 0.001g.

·Place the sample in a 524-593 (muffle furnace, burn for more than 15 minutes, or burn until all carbides are removed.

·Transfer the sample to a desiccator and cool it to room temperature.

·2eigh one by one (W2), accurate to 0.001g.

·Calculation: resin content = [(W1-W2) / W1] × 100%

The melting point of the FR-4 process pressure plate needs to reach 203 ℃, which has the characteristics of high chemical resistance. The low loss factor is Df 0.0025, and maintains a stable and low dielectric constant (Dk 2.35), is a thermoplastic material. FR-4 is an epoxy glass fiber cloth substrate, which is a type of substrate that uses epoxy resin as an adhesive and electronic grade glass fiber cloth as a reinforcement material. Its bonding sheet and inner core thin copper clad laminate are important substrates for making multilayer printed circuit boards.