JPH0254756A - Vacuum vapor deposition method for plastic film - Google Patents

Abstract

PURPOSE:To practically prevent the occurrence of heat affection in film and to improve the external appearance of a vapor-deposited film by cooling a film just before being brought into contact with a cooling can in coiling-type vacuum vapor deposition. CONSTITUTION:A roll for cooling, etc., are provided between a coiling and decoiling device and a cooling can in a coiling-type vacuum vapor deposition apparatus, by which a film just before being brought into contact with the cooling can is cooled down to <=0 deg.C. At this time, it is preferably to use, as the above film, a plastic film in which elongation in a longitudinal direction at the time of subjecting the film to temp. raise to 25-50 deg.C at a rate of 10 deg.C/min while applying a tension of 3kg per square meter of cross-sectional area in a longitudinal direction is regulated to <=0.15%, e.g., a polyphenylene sulfide film. By this method, the occurrence of heat affection at the time of metallic vacuum vapor deposition is practically prevented, and dimensional accuracy at the time of cutting the metallized film can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for vacuum deposition of plastic films.

[Prior Art] It is widely known that aluminum or the like is vacuum-deposited on a plastic film such as a polyester film or a polypropylene film to form a metallized film, and that the metallized film is used for applications such as capacitors. Further, Japanese Patent Laid-Open No. 60-255978 and other publications disclose that a polyphenylene sulfide film is vacuum-deposited with aluminum or the like to form a metallized film, and that the metallized film is used for applications such as capacitors. It is also widely known to use a winding type vacuum deposition machine to produce metallized films.

[Problems to be Solved by the Invention] Conventionally, however, when metal evaporation is performed on plastic films using a winding type vacuum evaporation machine, wrinkles tend to occur in the film on the cooling can of the evaporation machine, especially for thin films of 5μ or less. A phenomenon in which the wrinkles are fixed by the latent heat of the evaporated metal, leaving wrinkles on the metallized film and causing poor flatness (hereinafter referred to as "
The disadvantage was that it was easy to suffer from heat loss (sometimes referred to as heat loss). If you try to cut this metallized film that has suffered heat loss to make tape for capacitors, etc., the dimensional accuracy will deteriorate, and for example, the width of the margin part (non-evaporated part) will fluctuate, resulting in a defective capacitor. There are negative effects such as causing

The purpose of the present invention is to eliminate the above-mentioned drawbacks that occur during vacuum evaporation of conventional plastic films, and to provide a method for evaporating plastic films that is less susceptible to "heat loss" when metal evaporation is performed using a winding type vacuum evaporation machine. It's about doing.

[Means for Solving the Problems] In order to achieve the above objects, the present invention provides (1) a method for vacuum-depositing metal on at least one side of a plastic film using a winding-type vacuum deposition machine; This is a method for vacuum vapor deposition of a plastic film, characterized in that the temperature of the film immediately before being deposited is 0° C. or less.

In the present invention, the plastic film refers to a thin film made of any synthetic polymer and having a thickness of 5 μm or less. For example, polyester film, polypropylene film, polyphenylene sulfide film, etc. can be used, but polyphenylene sulfide is more effective.

In the present invention, polyphenylene sulfide film (
(Hereinafter, it may be abbreviated as PPS film) is a biaxially oriented film of a resin composition containing poly-p-phenylene sulfide as a main component. The thickness of the film is 0
．． Although the range is from 4 to 25 μm, a range from 0.4 to 10 μm is most effective. The average surface roughness Ra of the film is
In terms of workability during winding and adhesion during hot pressing after winding, the range is preferably from 0.03 to 0.10.

Further, it is preferable to use a crystallized film having a crystallinity of 25% to 45% as measured by X-ray diffraction. Furthermore, the orientation degree OF obtained for the crystal peak at 20 = 20 to 21°C by wide-angle X-ray diffraction is 0.07 to 0 in the End direction and Edge direction.
．． 5. It is preferable that the biaxially oriented film has an orientation in the range of 0.6 to 1.0 in the lrough direction.

Here, the resin composition containing poly-p-phenylene sulfide as a main component (hereinafter sometimes abbreviated as PPS-based composition) refers to a composition containing 70% by weight or more of poly-p-phenylene sulfide.

BoI, '-p-phenylene sulfide content direction is 70
If the amount is less than % by weight, the crystallinity, thermal transition temperature, etc. of the composition will be low, and the characteristics of the film made of the composition, such as heat resistance, dimensional stability, and mechanical properties, will be impaired. The remaining less than 30% by weight of the composition is a polymer other than poly-p-phenylene sulfide, an inorganic or organic filler, a lubricant,
It may also contain additives such as colorants and ultraviolet absorbers.

The melt viscosity of the resin composition is in the range of 5.00 to 12,000 poise (more preferably 700 to 10,000 poise) at a temperature of 300''C and a shear rate of 2001/sec in terms of film formability. It is preferable.

The melt viscosity of the resin composition is equal to the melt viscosity of the polyphenylene sulfide film finally obtained.

In the present invention, poly-p-phenylene sulfide (hereinafter sometimes abbreviated as PPS) refers to a polymer in which 70 mol% or more (preferably 85 mol% or more) of repeating units are structural units represented by the structural formula +S+. It means merging.

If the content of such components is less than 70 mol%, the crystallinity, thermal transition temperature, etc. of the polymer will be low, impairing the heat resistance, dimensional stability, mechanical properties, etc., which are the characteristics of a film made of a resin composition containing PPS as a main component.

Less than 30 mol% of repeating units, preferably 15 mol%
If the amount is less than 1, there is no problem even if a unit containing a copolymerizable sulfide bond is included.

Further, it is preferable that inorganic fine particles be contained in the film of the present invention for the purpose of adjusting the surface roughness.

In the present invention, while applying a tension of 3 Ky per 1 square millimeter of cross-sectional area in the longitudinal direction of the film,
It is preferable to use a plastic film whose longitudinal elongation is 0.15% or less when the temperature is raised to 0°C at a rate of 10°C/min in order to further reduce the occurrence of "heat loss." The magnitude of such elongation is more preferably 0.12% or less. Further, it is preferable that the elongation when the temperature is raised to 70° C. under the same conditions is 0.4% or less. Generally speaking, it is more preferable if the elongation when heated to 80°C under the same conditions is 0°4% or less.

There is no particular limitation on the method for controlling the elongation of the plastic film within the above range. For example, in the case of polyphenylene sulfide film, a resin composition containing poly-p-phenylene sulfide as a main component is supplied to an extruder or the like and melted using a well-known method described in JP-A-55111235, etc., and then passed through a T-die. The sheet is extruded onto a cooling drum to form a non-oriented sheet, and the sheet is biaxially stretched longitudinally and transversely simultaneously or sequentially at a temperature of 95 to 115 °C, and further heat-treated at a temperature of 200 °C or higher and below the melting point, Examples include a method of obtaining an intermediate and then heat-treating the intermediate at 30 to 120°C (preferably 30 to 70°C) for 5 seconds to 10 days. The time for the heat treatment can be appropriately selected depending on the temperature. In general, it takes a long time at low temperatures and a short time at high temperatures. The heat treatment can be carried out continuously with the production of the intermediate on a film production line, or can be carried out once the film has been wound up. In the case of a single barley, it can be carried out continuously while unrolling the film, or it can be carried out in a roll form in a hot air oven.

Further, the heat treatment can be performed in two or more stages at different temperatures. This method of heat treating an intermediate can also be applied to other plastic films such as polyester films.

A metal is vacuum-deposited on at least one side of the film using a continuous winding type evaporator. At this time, the temperature of the film immediately before it comes into contact with the cooling can must be kept below O'C. If the temperature is too high, heat loss is likely to occur.

In a vapor deposition machine equipped with two cooling cans for continuously vapor-depositing both sides of a film, it is necessary to satisfy the above temperature conditions for each cooling can.

There is no particular method for keeping the temperature of the film just before it comes into contact with the cooling can below 0°C, but at least one cooling roll should be provided between the unwinding machine and the cooling can in the winding type vacuum evaporation unit. , a method of cooling the film while it is running is preferred. In a deposition machine equipped with two cooling cans for successively depositing both sides of a film, it is preferable to provide a cooling roll in front of each cooling can. Alternatively, a method may be used in which the film is sufficiently cooled before being set on the unwinding machine.

It is preferable that the temperature of the refrigerant circulating in the cooling can be -15° C. or lower in order to further reduce heat loss.

The type of metal to be vacuum-deposited is not limited, but examples include aluminum, zinc, tin, copper, gold, and silver. Further, the method of heating the metal to be vacuum-deposited is not particularly limited, such as resistance heating method or electron beam heating method.

[Measurement method and evaluation method of properties] (1) Elongation 55o (or 5701s8Q> In the present invention, from 25°C to 50' while applying a tension of 3 Ky per 1 square millimeter of cross-sectional area in the longitudinal direction of the film
10℃ to C (or 70'C or 80'C)
To measure the elongation in the longitudinal direction when the temperature is raised at a rate of /min, cut out a test piece with a length of 1100 # and a width of 10 m in the longitudinal direction of the film, and apply 3KH per square millimeter of cross-sectional area of the test piece. Attach a load equivalent to 2 to the lower end and raise the temperature to 2.
Suspended in a hot air oven maintained at 5℃ for approximately 1000m.
Two optical position detectors (licensors) read the interval Lo between marked lines placed near both ends of the film at intervals of .
Raise the temperature of the hot air oven at a rate of 10℃/min to 50℃.
℃ (or 70℃ or 80℃), read the distance between the gauge lines again, and calculate 100X (L-Lo
)/Lo (unit: %) to calculate elongation of 55o (or 370 or 58o).

(2) Degree of "heat loss" during vapor deposition Aluminum was vapor-deposited on a film sample with a width of 500 m using a continuous winding type single-sided vapor deposition machine manufactured by Nippon Shinku Giken ■. At this time, the temperature of the refrigerant circulating inside the cooling can is -30℃, and
The vapor deposition was carried out in a stripe pattern in which m-wide vapor-deposited areas and 1-m-wide non-evaporated areas were alternately repeated.

The metallized film after vapor deposition was observed, and the degree of "heat loss" was determined based on the following criteria.

○: No wrinkles running in the vertical direction of the metallized film were observed.

△: Wrinkles running in the longitudinal direction of the metallized film are observed, but no waviness is observed as a whole, and the wrinkles disappear while tension is applied.

×: In addition to more than ten wrinkles running in the longitudinal direction of the metallized film, undulations were observed throughout the film, and the wrinkles remained even when tension was applied.

[Effects of the Invention] The vacuum evaporation method of the present invention has the above-mentioned configuration, thereby eliminating "heat loss" during evaporation, which was a drawback when metals were conventionally vacuum evaporated onto plastic films using a winding type vacuum evaporation machine. ”
As a result, when cutting 1q metallized film to make tape for capacitors, dimensional accuracy is improved and the defective rate of capacitors is reduced. Further, even when the obtained metal film is coated for the purpose of manufacturing a so-called lacquer coating type multilayer capacitor, it also has the effect that dimensional deviation from the coating pattern is less likely to occur. Furthermore, in applications where appearance is an issue, such as packaging, it can be expected that the appearance of the vapor-deposited film will be improved.

[Example] Next, examples of the present invention will be given and explained in detail.

Example 1 (1) Production of PP5-BO used in the present invention 32.6 KI of sodium sulfide (250 mol,
(contains 40 wt% of water of crystallization), sodium hydroxide 1009
, sodium benzoate 36°1 Kg (250 mol),
After charging 79°2KFl of mole), and NMP2
0. ONg was added and reacted at 265°C for 4 hours. The reaction product was washed with water and dried to obtain poly-p-phenylene sulfide 21.1Ny (yield 78%) consisting of 100 mol% p-phenylene sulfide and having a melt viscosity of 3100 poise.
) was obtained.

In this composition, fine silica powder Q with an average particle size of 0.7 μm is added.
,'l*t%, Calcium stearate 00Q5vt%
and heated to 310℃ using a 40m diameter extruder.
95% cut hole diameter 10 μm using metal fiber
After filtering with a filter, the length is 400m, and the interval is 1.5m.
extruded through a T-die with a straight lip of
It was cast on a metal drum kept at 5°C and cooled to solidify, yielding 1 q of unstretched film with a thickness of about 20 μm.

This film is stretched by a longitudinal stretching device consisting of a group of rolls.
The film was stretched 3.6 times at a film temperature of 100'C and a stretching speed of 30,000%/min.
, stretched 3.5 times at a stretching speed of 1000%/min, and then heat treated under tension at 270'C for 10 seconds in a subsequent heat treatment chamber in the same tenter to obtain a 2 μm thick intermediate (intermediate -
1) was obtained.

The intermediate was wound into a roll, and the roll was heat-treated in an oven at 50°C for 72 hours to obtain 1q of polyphenylene sulfide film (film-1). The "elongation" S5o of the film according to the present invention was 0.11%.

On this film-1, aluminum was vapor-deposited onto a film sample having a width of 500 m using a continuous winding single-sided vapor deposition machine manufactured by Nippon Shinku Giken ■. At this time, a refrigerant at -30°C was passed through the two rolls immediately before the cooling can, and the temperature of the film immediately before contacting the cooling can was set to -10°C (condition 1). The temperature of the refrigerant circulating in the cooling can was set to -30'C, and the refrigerant was deposited in stripes in which 9 m wide deposited areas and 1 m wide undeposited areas were alternately repeated. In addition, by appropriately changing the temperature of the refrigerant passed through the two rolls immediately before the cooling can, vapor deposition was carried out in the same manner under three other conditions (conditions 2 to 4) in which the film temperature immediately before contacting the cooling can was different.

The results are shown in Table-1. When deposited under the temperature conditions of the present invention,
It can be seen that "heat loss" during vapor deposition is less likely to occur.

Example 2 1q of the intermediate 1 in Example 1 was wound up into a roll, and heat treated in the same manner as in Example 1, changing the heat treatment temperature and time appropriately, to form a film in the longitudinal direction of the present invention. Four types of films (Film-2 to Film-5) was obtained. Aluminum was vacuum-deposited on these films under Condition 1 in the same manner as in Example 1. The evaluation is shown in Table-2.

Claims (4)

[Claims] (1) A method of vacuum-depositing metal on at least one side of a plastic film using a winding type vacuum deposition machine, wherein the temperature of the film immediately before contacting the cooling can is set to 0°C or less. vacuum evaporation method. (2) The plastic according to claim (1), characterized in that at least one cooling roll is provided between the unwinding machine and the cooling can in the winding type vacuum deposition machine to cool the running film. Vacuum deposition method for film. (3) 10°C from 25°C to 50°C while applying a tension of 3 kg per square millimeter of cross-sectional area in the longitudinal direction of the film.
The elongation in the longitudinal direction is 0.15 when the temperature is raised at a rate of /min.
% or less. (4) Claims (1) to (3) characterized in that the plastic film is a polyphenylene sulfide film.
) The method for vacuum deposition of a plastic film according to any one of the above.