JPS61130043A - Laminated film - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a laminated film.

More specifically, the present invention relates to a laminated film in which polyethylene terephthalate film is laminated, which is suitable for dielectrics for capacitors, base paper for stencil printing, base films for typewriter ribbons, and the like.

[Prior art]

In recent years, as electrical equipment has become smaller and lighter, applications such as capacitors have become increasingly smaller, and the films used there are also required to be thinner. As such an ultra-thin film, for example, JP-A-58
-5226.58-132520.58-136417
．． 57-176125.52-37982, etc., is known in which different types of polymers are laminated and stretched to form a laminated film, and then one side is peeled off and used as an ultra-thin film.

[Problem that the invention seeks to solve]

Such conventional laminated films are easily torn and pinholes are easily formed when peeled off. Further, the obtained ultra-thin film had a problem in that the water vapor permeability was higher than that of a normal film of around 10 μm, and the dielectric breakdown voltage was extremely low.

An object of the present invention is to provide a laminated film having fewer of the above-mentioned drawbacks, that is, a layer of ultra-thin polyethylene terephthalate film having a low water vapor permeability and a high dielectric breakdown voltage, and also having good peelability. It is something.

[Means for Solving the Problems] In order to achieve the above object, the present invention has the following configuration, that is, at least one side of the propylene copolymer layer contains 0.05 to 1% by weight of higher fatty acid wax. Polyethylene terephthalate layers are laminated, and the polyethylene terephthalate layer has a thickness of 0.2 to 2.0 μm.
m, water vapor transmission rate is 4.0-6.00/m2・27! l
It is characterized by a laminated film of 11r10.1 mm.

The propylene copolymer (hereinafter abbreviated as PPC) layer in the present invention is a layer having a melting point of 100 to 150°C, and is not particularly limited as RPC, but contains 80 to 97 mol% of propylene and other than propylene. olefin 3
A polymer comprising a copolymer with ~20 mol % of QT is preferred. Specific examples include a propylene/ethylene copolymer, a propylene/butene copolymer, a propylene/ethylene/butene terpolymer, or a mixture thereof. As for the copolymerization mode, a random copolymer is preferable, but a block copolymer can also be used depending on the degree of blocking. Note that it may be a mixture of a propylene copolymer and other polyolefins (eg, polyethylene, polybutene, etc.).

Moreover, the intrinsic viscosity of RPC is 1.0 to 2. It is preferably in the range of Odα10. When it is within this range, it is preferable because the thickness unevenness of the film is reduced.

In addition, known additives such as non-particulate lubricants, inorganic fine particles, coloring pigments, waxes, etc. may be added to PPC.

The thickness of the PPC layer is preferably in the range of 5 to 30 μm.

Polyethylene terephthalate (hereinafter referred to as P
A layer (abbreviated as ET) is a layer containing 90 mol% or more of the molecular composition.
is a polymer layer consisting of ethylene terephthalate units, and the melting point of the polymer in this layer is preferably 250°C or higher, preferably 255°C or higher. Of course, as long as the ethylene terephthalate unit does not fall below 90 mol%,
Copolymerized units of known copolymerized molecular units, such as ethylene isophthalate, butylene terephthalate, ethylene adipate, ethylene sebacate, and polyethylene glycol, are also included in the PET referred to in the present invention.

The thickness of the PFT layer is 0.2 to 2. Ottm, preferably 0.2 to 1.5 μm. If the thickness is thinner than 0.2 μm, it is not preferable because there is a problem of tearing during film formation.

In addition, when the thickness is more than 2.0 μm, preferably 1.5 μm, the workability is good and the dielectric breakdown voltage can be maintained high even when used as a single film, so it is necessary to form a laminated film as in the present invention. do not have.

Further, the PET layer of the present invention needs to contain higher fatty acid wax. The higher fatty acid wax contained is a fatty acid ester compound whose main components are a higher fatty acid having 17 to 33 carbon atoms and a polyhydric alcohol having 17 to 33 carbon atoms, and specific examples include:
Shellac wax, cotton wax, Higashiguchi wax, Montan wax, wool wax, carnauba wax, candelilla wax, cotton wax, synthetic wax, etc., and some or all of the fatty acid esters of these waxes are replaced with other alcohol components, or sodium It is a modified product of metal salts of alkali metals such as potassium, or alkaline earth metals such as calcium, magnesium, barium, etc., and has a hydrocarbon compound content of 50% by weight or less and is solid at room temperature. Particularly desirable among these are carnauba wax, montan wax, synthetic waxes, and modified products thereof. Here, the main component refers to a fatty acid ester compound containing a total amount of 50% by weight or more of a higher fatty acid having 17 to 33 carbon atoms and a polyhydric alcohol having 17 to 33 carbon atoms.

Here, the number of carbon atoms in higher fatty acids and polyhydric alcohols is 17.
If it is less than 100%, the higher fatty acid wax will bleed out to the film surface severely, causing trouble in the film forming process, and the adhesion in vapor deposition or alkali coating will be significantly poor. If the number of carbon atoms exceeds 33, the PET layer is likely to have holes, causing film tearing. The content of the higher fatty acid wax is PE
It needs to be 0.05 to 1% by weight with respect to the T layer,
Preferably, it is 0.11 to 0.8%. The above content is 0
．． If the amount is less than 0.05% by weight, pinholes will increase, resulting in poor dielectric breakdown voltage and water vapor transmission rate. Content is 1
If it exceeds % by weight, the thickness unevenness of the PET layer becomes severe and film tearing occurs.

Furthermore, the P[ET layer of the present invention has a water vapor transmission rate of 4.0.
~6.00/vn2・24hr10.1 mm. A water vapor transmission rate of less than 4.0 is also preferred, but is difficult to achieve with PET. Water vapor transmission rate is 6.
If it exceeds 0, the number of pinholes will increase and the dielectric breakdown voltage will decrease.

Preferably, fine particles are added to the PET layer, and the particles preferably have a number average projection diameter of 1.5 to 4 μm, more preferably 1.8 to 2.8 μm. As the fine particles, inorganic fine particles such as dry silica, wet silica, zeolite, calcium carbonate, calcium phosphate, kaolin, kaolinite, clay, talc, titanium oxide, alumina, zirconia, aluminum hydroxide, etc. are preferable, and the amount added is It is 0.01 to 1.0% by weight. It is preferable to add fine particles in this manner because the effect of the higher fatty acid wax can be synergistically enhanced.

The laminated film of the present invention is a lamination of the above-mentioned PFT layer and PPC layer, and the laminated structure is not particularly limited.
Two layers of /RPC, three layers of PET/PPC/PET, or five layers of PET/PPC/PET/PPC/PET are preferred.

The ratio A/B of the thickness A of the PE7 layer 1H and the thickness B of one PPC layer (if there are multiple layers, the thickest layer) is 0.0
1 to 0.2 is preferred. If it deviates from this range, it tends to become difficult to form a film. Further, the laminated film is preferably stretched in the two-wheel direction to impart molecular orientation.

Next, a specific example of the method for manufacturing the laminated film of the present invention will be explained. However, it is not limited to this example.

PET chips containing a specific amount of higher fatty acid wax and RPC chips are each fed to separate extruders.
A non-stretched laminated sheet is made using the coextrusion method.

Stretched 3.0 to 4.0 times in the longitudinal direction at 80 to 100°C, then stretched 5 times in the width direction at 90 to 120°C, 4.0 to 5°,
Thereafter, the laminated film of the present invention can be obtained by heat treatment at 180 to 220°C.

In addition, well-known methods can be applied to all of the above-mentioned coextrusion method, stretching method, heat treatment method, etc.

The thus obtained laminated film is printed, laminated, coated, or vapor-deposited on the PET surface, and then coated with PP.
The C layer is peeled off and used. This peeling method is not particularly limited, but if the laminated film is nipped between 111 nip rolls and the PET film is peeled along the surface of one of the rolls, continuous peeling is easy. Note that the above printing etc. may be performed after peeling.

-〇1 The laminated film of the present invention can be used for many purposes such as a dielectric for capacitors, base paper for stencil printing, and base film for typewriters.

[Effect]

In the laminated film of the present invention, since the PET layer contains a specific amount of higher fatty acid wax, the peeling between the PET layer and the PPC layer is significantly improved, pinholes are reduced, and the PET layer has a specific amount of higher fatty acid wax.
It is thought that even if particles are added to the ET layer, the affinity with the particles improves and voids disappear. Thereby,
It is thought that the dielectric breakdown voltage and water vapor transmission rate were improved.

[Method of measuring physical properties]

The method of measuring physical properties used in the present invention is as follows.

(1) Thickness of the film A film is pasted on a glass support without wrinkles, and measured with a stylus surface roughness meter to measure the boundary between the areas where there is no film and the area where the film is present. The difference in level was measured and defined as the fill thickness = 10-.

(2) Wax content: Films with varying amounts of wax added were made, and 1''-NMR spectra were measured at a resonance frequency of 400 MHz to create a calibration curve. The wax content of the PFT layer was determined from a relative comparison with the film to be measured.

(3) Number average protrusion diameter Aluminum vapor deposition on PFT film (thickness 0° 1 μm)
L. The number of surface projections on the film and the individual area of the projections were quantitatively measured using an optical microscope (32×8 magnification) and an analyzer (50 fields of view).

The area of each protrusion was converted into an equivalent circle diameter, and the average value of each equivalent circle diameter was determined to be the number average protrusion diameter.

(4) Water vapor permeability A sample cup was prepared according to the method of JIS 20208, and the water vapor permeability (0/Tn'・24hr10.1mm>) was determined.

(5) Number of pinholes Ultra-thin PET film with aluminum vapor-deposited on one side,
Spread it out on a copper plate, making sure there are no wrinkles. At this time, the PET film is sandwiched between copper and aluminum with the vapor deposition side facing the "-" side. and,
During this time, a DC voltage of 100 V per 0.5 μm film thickness was applied for 5 seconds using copper and aluminum as electrodes. Then, a current flows between the electrodes in the pinhole portion, and the vapor-deposited surface partially disappears, so by this method, the number of pinholes per unit area of the film can be determined.

Here, the number of pinholes is expressed as (number/100o()).

(6) Dielectric breakdown strength A DC voltage was applied to a 10 cm square film, and the voltage at which dielectric breakdown occurred was measured. The value obtained by dividing the dielectric breakdown voltage by the thickness of the film (V/l1m) was expressed as the dielectric breakdown strength. Incidentally, the pressure increase rate was set to 50 .mu./SeC.

〔Example〕

Hereinafter, one embodiment of the present invention will be described based on Examples. Of course, this example does not restrict the content of the present invention.

Example 1 Hara F with two types of manure! 1 (pellet) was prepared.

PET: Intrinsic viscosity 0.6267110. Melting point: 259°C.

Carnauba wax 0.5% by weight (the content in the film was adjusted to this value) and dry silica 0.5%
% by weight.

PPC: Intrinsic viscosity 1.656ff/b °C. A propylene/ethylene random copolymer with an ethylene content of 6% by weight.

These two types of raw materials are supplied to separate extruders, and the
Melt extrusion at ℃, the respective melts were merged in a T-shaped nozzle to form a three-layer structure of PFT/PPC/PET, and this was wound around a cooling drum at 25℃ to cool and solidify.
It was made into a three-layer laminated sheet.

The thickness of the PET layers on both sides was 8 μm each, and the thickness of the PPC layer at the center was 230 μm.

This sheet was heated to 90°C, stretched 3.4 times in the longitudinal direction, and immediately cooled to 30°C.

Next, it was heated again to 100°C, stretched 4°6 times in the width direction, and while maintaining the tension, was heat treated at a temperature of 200°C for 6 seconds, slowly cooled, cooled to room temperature, and rolled up. . The obtained film was a laminated film in which the thickness of the PET layers on both sides was 0.5 μm, and the thickness of the PPC layer at the center was 15 μm.

When the PET layer was peeled off, the peelability was good.

The number of pinholes in this ultra-thin PET film is 1.
As few as 0 pieces/100ty#, the number average protrusion diameter is 2.0μ
It was m. In addition, the water vapor transmission rate is 5゜0g/1T1
2.24hr 10.1mm, dielectric breakdown strength is 32
The voltage was 0V/μ, which was good.

Comparative Example 1 Carnauba wax added to the PET raw material of Example 1 was added to 1.
A film was formed in the same manner using 5% by weight and 0.5% by weight of dry silica. The stretchability was poor, and when the film was stretched horizontally, holes and tears occurred frequently, making it impossible to obtain a satisfactory sample.

Comparative Example 2 The amount of carnauba powder added to the PET base of Example 1 was 0.
01% and dry silica was changed to 0.5% to form a film in the same manner. In the obtained film, the thickness of the PET layers on both sides was 0.5 μm, and the thickness of the PPC layer at the center was 15 μm. When the PET layer is peeled off and the number of pinholes is measured, it is 5.
The number was 0/100d, which was higher than in the example. The number average projection diameter was 2.5 μm. The water vapor permeability of this ultra-thin PET film is 6.5Q/Tl12・24hr10.1
1TITl, and the dielectric breakdown voltage was poor at 270V/μm.

Comparative Example 3 A film was formed in the same manner as in Example 1, except that the carnauba wax in the original PET format was omitted and only 0.5% of dry silica was added.

In the obtained film, the thickness of the PET layers on both sides was 0.
The thickness of the PPC layer at 5 μm 1 center was 15 μm. P
When the ET layer was peeled off and the number of pinholes was measured, it was 66/1.
00d, which was higher than in the example. The number average projection diameter is 2.
It was 6 μm. The water vapor permeability of this ultra-thin PET film is 6.20/i2・24hr10.1mm,
The dielectric breakdown voltage is 250V/μm, which is quite bad.

〔Effect of the invention〕

In the present invention, the laminated film contains an appropriate amount of higher fatty acid wax in the PET layer, so that the peelability between the PET layer and the PPC layer is improved and pinholes are reduced. As a result, water vapor permeability and dielectric breakdown strength were improved.

Patent Applicant Toshi Co., Ltd. Company Procedural Amendment 60.5.2 Date of Showa Date Manabu Shiga, Commissioner of the Patent Office1, Indication of the case 1982 Patent Application No. 2515592, Name of the invention Laminated film3, Relationship with the case of the person making the amendment: Patent applicant 4, date of amendment order issued 5, number of inventions not increased by the amendment 6, "Detailed description of the invention" column 7 of the specification to be amended, content of the amendment (1) "Film" on page 10, line 17 of the specification: [For films thicker than 2 μl, the measurement was performed using a dial gauge. ``For films of 21 tm or less,'' it is corrected.

(2) Same page 11, line 12 Correct "individual area" to "individual area".

(3) Same page 11, line 15 Complement "water vapor transmission rate" with "water vapor transmission rate".

(4) Same page 12, line 19 1. ``To the present invention'' shall be amended to ``of the present invention''.

Claims (1)

[Claims] A polyethylene terephthalate layer containing 0.05 to 1% by weight of higher fatty acid wax is laminated on at least one side of the propylene copolymer layer, and the polyethylene terephthalate layer has a thickness of 0.2 to 2.5% by weight. 0μm
, water vapor transmission rate is 400-6.0g/m^2・24hr
/0.1mm laminated film.