At present, IC cards have been widely used in various fields of society. In 2005 alone, the global circulation reached 3.86 billion. Mainly used in communications, banking, medical, transportation, supermarket shopping, school fees and online transactions. The Ic card entered China late, but under the strong promotion of the â€œGolden Card Projectâ€, it has developed very rapidly and has become the fastest-distributing country in the world. In 2005, China issued 67.95 million Ic cards, with total sales reaching 652.32 million yuan. The number of card issuance and sales increased by 19.1% and 29.3% respectively compared with 2004. Faced with such a huge market and circulation, the traditional production process of IC cards (dropping production line) has been unable to meet the needs of the times. This kind of production method is easy to cause the overflow of the glue and pollute the chip; and the amount of glue used in the bonding process is more or less, which makes the product quality unstable; in addition, the production efficiency of the drip production line is low, and the working environment of the worker is poor. In order to improve production efficiency and product quality, and to improve the working environment, we will make the selected adhesive into packaging tape, pre-bond the chip module and tape, then punch it, and finally stick it to the PVC card. This packaging tape is ideal for automated line production. At present, there are a few manufacturers in China that are developing such packaging tapes, but their performance is not well enough to meet the requirements of continuous production lines. Therefore, IC card manufacturers mainly rely on imported packaging tape from abroad for production. This increases the production cost of the Ic card, which adversely affects the efficiency of the enterprise and the improvement of competitiveness.
2 Experimental part
The packaging of the chip is an indispensable key process in the production process of the IC card. It plays a very important role in the overall quality and service life of the IC card. This puts high demands on the quality and process adaptability of the packaging tape itself. To this end, we have conducted research and development on the basis of understanding the packaging process.
2.1 Raw materials for testing
Thermoplastic polyurethane adhesive, CaCO, talc, dioctyl phthalate, coupling agent, thixotropic agent, mixed solvent
2.2 Test equipment
Oven, mixer, ball mill, coater, slitting machine, packaging machine
2.3 Test process
(1) Pretreatment of the filler, drying the CaCO, talc, and SiO at 100oC; (2) preparing the glue, dissolving a certain amount of the adhesive material in the mixed solvent, and sequentially adding the filler and the auxiliary agent. Stirring, ball mill dispersion; (3) coating test on adhesive at a certain temperature and speed and matching test of anti-adhesive paper and surface tension of glue; (4) slitting; (5) adapting IC card chip package Sex test. According to the test results, the formula and production process of the Ic card recording chip packaging tape are determined.
3 Results and discussion
3.1 The main performance of the adhesive on the process performance
It can be known from the IC card chip packaging process that in the production process of the IC card, the adhesive layer of the packaging tape is required to be easily peeled off from the tape base, and the adhesive layer and the chip are required to have a short pre-bonding time and good punching performance, and the key is When the chip is finally bonded to the PVC card, the adhesive layer is required to melt rapidly at the set temperature and solidify in 1-2 s, and have sufficient bonding strength. In the manufacturing process of the packaging tape, the first choice of the appropriate adhesive and tape base, then how to make the adhesive evenly distributed on the tape base and does not automatically detach, and the packaging tape can also meet the requirements of the Ic card continuous production line, which Specific requirements have been placed on the tape manufacturing process. To this end, we use thermoplastic adhesives as research objects. Depending on the base resin used, thermoplastic adhesives can be mainly classified into ethylene-vinyl acetate (EVA), polyamide (PA), polyester (PET), and polyurethane (PU).
By comparing the performance of several types of thermoplastic adhesives, we first selected polyurethane thermoplastic adhesives with good adhesion and processability as raw materials for this experiment. At the same time, considering the wide variety of polyurethane thermoplastic adhesives, according to their differences in composition, properties and use, TDI series thermoplastic adhesives were selected and their specific physical properties and processability were compared. The results are as follows:
Table 1 Comparison of properties of thermoplastic polyurethane adhesives
From the point of view of the production process of the IC card, the bonding of the PVC card and the adhesive layer needs to be completely cured in the time of 1-2 s, and it is required to achieve a certain bonding strength, so the curing speed of the adhesive should be considered when selecting the adhesive. And bond strength. It can be seen from Table 1 that under the premise of good bonding strength, when the glass transition temperature is low and the crystallization rate is fast, not only the curing speed is fast but also the bonding strength is good. When the glass transition temperature is high and the crystallization speed is slow, the curing speed is slow and the processability is also poor. In consideration of various performances such as process possibilities, the glass transition temperature is relatively low, and the crystallization rate is also fast. T-5201 H is used as a raw material for making adhesive tape.
3.2 Effect of release paper on process performance
The choice of release paper is also an important part of the entire process. Two anti-adhesive papers were used in this experiment, one with PE film and the Other without PE film. Each of the three different grams of paper was selected for trial application. The experimental results are shown in the following table:
Table 2 Comparison of anti-adhesive paper coating effects
Through the test coating, it was found that the glue on the release paper without the PE film was evenly distributed, and the glue layer did not peel off after drying. According to the analysis, when the liquid is in contact with the solid surface, the two molecules in the interface zone are attracted by the same kind of molecules on the same side of the interface, and the fork is attracted by the heterogeneous molecule on the other side. The joint force of the two attractive forces is called interface. tension. If the solid is of low surface energy, its attraction is lower than that of the liquid phase molecules, and the liquid molecules in the interfacial zone have a tension that shrinks toward the interior of the liquid, which is the non-wetting state; if the solid is a high surface energy solid, its attraction The force is higher than the attraction of the liquid phase molecules. Then, the liquid molecules in the interface region have a pressure that is adsorbed to the solid, and a wet state is formed, so that the liquid-solid interface is tightly bonded, which is not conducive to the peeling of the rubber layer for the purpose of the test. If the surface energy of the solid and liquid is chosen to be similar, the glue can be evenly distributed on the solid surface, and the interface bonding is not very tight, which is beneficial to the peeling of the glue layer. When the PE film is coated, the surface tension of the paper is reduced, the surface tension of the glue is greater than the surface tension of the paper, and the glue has a shrinkage phenomenon. When using a film-free release paper, the surface tension of the glue and the release paper is relatively close, and the glue can be evenly distributed on the surface of the release paper while also meeting the requirements for easy peeling. Through the test analysis, combined with the paper itself in terms of toughness, punching, non-hygroscopicity and economical life, 90g of anti-adhesive paper without PE film was finally selected.
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