FI61919C - SAETT ATT VACUUMMETALLISERA PLASTFOLIER PAO ENA SIDAN SAMT ANVAENDNING AV DESSA FOLIER - Google Patents

Description

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Patents and registers are filed under the term of filing. - 30.06.82

Patent · och ragistarstyraitan Aiwttkan utltgd och utl. »Krlfun publkerad (32) (33) (31) PyrdKty« Tuoikaua —Bogird pHorltat 09.03.77

Federal Republic of Germany-Förbundsrepubliken Tyskland (DE) P 2710132.2 (71) Hoechst Aktiengesellschaft, Postfach 80 03 20, 6230 Frankfurt / Main 80,

Federal Republic of Germany, Förbundsrepubliken Niemcy (DE) (72) Gunther Crass, Taunusstein, Dieter Gebhardt, Wiesbaden, Federal Republic of Germany, Förbundsrepubliken Niemcy (DE) (7 * 0 Oy Kolster Ab, (5 * 0 Type tyhjömetalloida the other side of the plastic films, and these films use - Sätt att vakuummetallisera plastfolier pa ena sidan samt användning av dessa folier

The present invention relates to a method for vacuum metallizing plastic films and to the use of films made according to the invention.

Vacuum metallization of substrates, e.g., plastic films, is generally prior art.

Thus, it is known to metallize, for example, plastic films with equipment similar to single-sided or double-sided. An overview of the methods for such equipment can be found, for example, in "Veredeln von Kunststoff-0berflächen", Carl Hauset Verlag, Munich, Vienna, 1974, paragraph 5, page 107.

However, as mentioned therein, difficulties occur in commercially available general equipment, especially when it is necessary to metallize films with a thickness of 10-5 [mu] m or less, as is currently used, for example, in the manufacture of capacitors. Thus, the tension of such films in rewinding and unwinding should be kept low to avoid tearing. In this case, however, the driving speed is 2,61919. Since the films necessarily have irregularities in thickness in the direction transverse to the direction of travel of the film due to the method of making the flat films, i.e. it has thick and thin points, oblique stretches and / or folds are created, which give unevenness to the metallization. However, such films cannot be used for high-end applications, e.g. in the manufacture of capacitors.

Thus, the task arose to develop a way in which said difficulties in metallizing thin plastic films can be prevented.

The invention is a method tyhjömetalloida other side of the polypropylene or polyester films which are biaxially stretched and having a thickness of 10 microns and less, to provide a 10-1000 Å layer of metal.

The method according to the invention is characterized in that at least two coated plastic films are passed through the metallization device and metallized therein in a manner known per se.

In the method according to the invention, higher track tensions can be used without said tears. This guarantees a faster driving style.

A significant additional advantage is that there are no longer any oblique pleats or stretches that lead to defective metallization. Also, no stretching or stretching occurs during winding, as would otherwise be the case with thin films, especially hard rolls, possibly due to the thick and thin spots present in the individual film layers.

An additional technical and economic improvement can be seen in the increase in production volume when the equipment is used with double-sided metallization, as, for example, the preparation times of the equipment are reduced.

A considerable advantage is also seen in the fact that the overlapping films, when used as capacitor films, are preferably no longer separated after metallization but are introduced in an overlapping form into the manufacture of the capacitor. In this way, no contamination can occur on the inner sides, e.g. from their electrostatic attraction, etc., which reduces the output in the manufacture of capacitors.

When it is desired to separate the overlapping films, there is also the advantage of dust-free inner sides when the separation and further processing into capacitors takes place in dust-free spaces.

The films to be metallized on the outside are preferably run in two superimposed film paths.

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However, for many special applications, e.g. special capacitor windings, it has proved expedient to involve additional film paths through the equipment, without, however, metallizing the inner layers.

Although overlapping plastic films have, in principle, varying strengths, or can be formed from different polymers, in practice it has proved particularly expedient to place two plastic films made of the same strength and Selmo materials together.

More preferably, the strengths of the individual plastic films are about 10 μm and below.

The plastic films which can be used in particular in the manufacture of capacitors are preferably those made of polystyrene, polycarbonate, in particular polypropylene or polyester. These films are preferably oriented, in particular biaxially oriented.

In the preferred process, plastic films made in accordance with German patent application P 24 31 385.7-16 (DT-OS 24 31 385) are metallized. This procedure has the additional advantage that the films on top of each other in at least two layers were already stretched in this form and were no longer separated before being fed to the metallization plant. This avoids the risk of fouling of the inner sides after stretching.

For metallization, all suitable, single-sided or double-sided metallization equipment can be used, in which case the one-sided metallization equipment is turned or rewound so that the second outer side can also be metallized.

The present invention is further illustrated by the following examples.

Example 1

In the metallization plant of the trade name HERAEUS, Type A 500 B 2, a biaxially stretched polypropylene film with a thickness of 8 μm was metallized on one side with aluminum with a thickness of 50 A.

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The width of the film was 350 mm. The metallization was carried out under a vacuum of 2.7 '10 mbar, whereby the current consumption to the four evaporators was 23 A. The guide roll was cooled to + 10 ° C. The track tension could be set, to avoid tears, to only 11.2 N, which corresponded to a tension of 4 N / mm, resulting in a driving speed of only 180 m / min. The metallization was uneven during the running of the track due to the formation of the film pleats.

Example 2

Worked under the same conditions as in Example 1, 2 however, the track tension was set at 14 N corresponding to a tension of 5 N / mm. There were a total of 16 ruptures per 100,000 m total run length, which required the equipment to be restarted each time, resulting in significant energy and time losses.

Example 3

Worked under the same conditions as in Example 1, however, a biaxially stretched polyester film with a thickness of 8 μm was metallized. The track tension was 22.4 N corresponding to a tension of 8 N / mm, running speed 180 m / min. The film was unevenly metallized due to creasing.

Example 4

Work was carried out analogously to Example 3, but with the track tension adjusted to 28 N corresponding to a tension of 2 10 N / mm. With a total length of 100,000 m, 21 cracks were observed, which required significant re-installation times.

Example 5

The conditions of Example 1 were repeated, however, two biaxially stretched 8 μm polypropylene films were superimposed on a straight edge and passed through a rewinding apparatus, with both outer sides metallized with 50 Å aluminum. The track tension could be increased to 16.8 N, corresponding to a tension of 3 N / mm ^, and the running speed to 250 m / min without tears. By preventing creasing, both surfaces were metallized evenly and flawlessly.

Example 6

Working under the conditions of Example 5, however, a two-layer film prepared according to DE patent DT-OS 2 431 385 2 was used. At a track tension of 16.8 N, which corresponded to a tension of 3 N / mm and a running speed of 250 m / min, no tears were also observed, as well as the metallization was smooth and flawless. In addition, test measurements with a dust measuring device, as described in CA Patent 990,097, resulted in much less dust particles on the inner sides of the bilayer films than on the other films.

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Example 7

Working under the conditions of Example 3, however, two biaxially stretched 8yum polyethylene terephthalate films were run in a straight edge superimposed through a rewinding apparatus, the exteriors being metallized with 50 Å aluminum. The track tension could be increased to 2 33.6 N, corresponding to a track tension of 6 N / mm, and the running speed to 250 m / min without tears. Vene formation was then avoided so that both surfaces were evenly and flawlessly metallized.

Example 8

Example 7 was repeated, however, a two-layer film prepared according to DE patent application 2,431,385 was used. With respect to dust freedom, the results were as good as in Example 6.

Example 9

According to Examples 5-8, the metallized films were used after cutting into narrow strips, both separated and in overlapping form, for the manufacture of capacitors of the most diverse structures. It turned out that significantly less interference or waste was generated, especially when using inseparable films.

As the examples clearly show, the invention provides both methodological and economic advantages over the prior art.

The figure shows a section (non-scale representation) of the two-layer film 1a, Ib with the outer metal layers 2a and 2b.