Scrap CD recycling in the recycling of polycarbonate III

Third, the possibility of reuse of recycled polycarbonate

The reuse of recycled polycarbonate for the production of CD-ROMs has traditionally been the result of pirated CDs. Therefore, I have been opposed to the reuse of recovered polycarbonate for the production of CD-ROMs and also against the production of food-grade products (such as drinking cans and national laws). The use of recycled materials in food-grade products is prohibited, and the use of non-food-use mechanical and electrical parts as well as daily necessities, etc., is premised on the premise that product standards must be met.

Such as pirated CDs, VCDs, CD-Rs, etc., some of them are broken and must be processed with polycarbonate recovered without chemical reaction processes that strictly control the reaction process; some CD-R substrates may even contain aluminum. Crumbs.

However, the rapid increase in the market price of polycarbonate in 2004 and the rapid decline in the price of optical disc processing have caused the cost of polycarbonate in almost every optical disc to almost double, and almost none of the optical disc replication factories can withstand the increase in raw materials. Because the price of polycarbonate raw material for each CD is almost above 0.60 yuan, the factory has no profit. Whether recycled polycarbonate can be used is on the agenda.

So, can the recycled polycarbonate be used for the reproduction of optical discs? We need to compare the quality index of recycled polycarbonate with the new disc quality polycarbonate quality index.

According to a company's CD-level polycarbonate new material index and its recycled polycarbonate index are as follows:

The above reclaimed material is the polycarbonate crushed material that was recovered for the first time in the new material and recovered from the entire mechanical grinding plate. Because it is the same brand of polycarbonate, although the conditions and standards for domestic testing are different, the following preliminary results can be obtained: (1) The fluidity is improved due to the decrease of the molecular weight; (2) the yield strength is reduced by about 3%; (3) the light transmittance and the heat distortion temperature change little; (4) the notched impact strength is decreased (but actually Not obvious in use).

In order to save the cost of polycarbonate raw materials under the premise of guaranteeing the quality of optical discs, some well-known optical disk copy factories in Taiwan have used the recycled polycarbonate raw materials for the blank information base of DVDR optical discs, since this 0.6 mm film base only provides The size, strength, adhesion, and printing surface make it possible to meet the overall performance requirements of DVDR discs. As long as the quality of recycled polycarbonate is well understood, the quality of DVDR discs can be guaranteed.

By the same token, quality-recovered polycarbonate raw materials can also be used for the informationless film bases of DVD5 and DVD9 discs.

As to whether or not the recycled polycarbonate can be used for the production of CD-ROMs, the production of the raw materials used in the granulation process, the formula of the granulation process, the cleanliness of the granulation environment, and other factors are quite different. Basically, CDs with information carry a greater quality risk, and publishers must recognize and assume the corresponding risks. Once quality problems arise, CD replication factories and publishers also face the problem of corporate reputation.

Four, granulation process is to grasp the quality of recycled polycarbonate

Polycarbonate recycling discarded discs, granulation process is to grasp the final quality of recycling.

First, what kind of raw materials are used for granulation, and those companies that do better use most of the optical disc injection ports, and a small part of the discs to recover the polycarbonate of the optical disc, so that the performance indicators of the produced pellets are close to the quality of the recycled materials in the above table. If chemical reaction methods are used to treat polycarbonates that recycle discs, it is difficult to achieve the above quality.

Second, what formula to use. The addition of antioxidants is essential to prevent oxidation reduction of polycarbonate during hot processing, otherwise it will reduce the molecular weight and reduce the strength and discoloration; there are also brighteners added to improve the appearance quality.

Third, the granulated raw materials must all be thoroughly cleaned to prevent acid-base residues and prevent non-polycarbonate impurities from mixing. At the same time, high-mesh filters must be used to filter out mechanical impurities.

At the same time, high-mesh filters must be used to filter out mechanical impurities. The environment must be very clean to prevent the intrusion of foreign substances. (to be continued)