JPS59136250A - Evaporated 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 This invention relates to improvements in vapor deposited films, and more particularly to biaxially oriented polypropylene films deposited with metals such as aluminum.

BACKGROUND ART Conventionally, films prepared by subjecting a biaxially stretched polypropylene film to surface treatment and vapor-depositing metals such as aluminum have been widely used for general packaging purposes. However, the vapor deposited film obtained by the conventional method, which is a method using only the surface treatment of the nails, does not have sufficient vapor deposition adhesive strength, and the vapor deposited film is easily damaged and peeled off due to abrasion. Also, the strength of the vapor deposition bond is not sufficient.

The deposited film may also be stripped off due to blocking under high temperature and high humidity conditions (especially in the summer).

For vapor-deposited films that have particularly excellent gloss and reflectivity,
This phenomenon was even more noticeable.

In view of these circumstances, the object of the present invention is to provide a vapor-deposited film with strong adhesion and sufficient resistance to wear and friction during the manufacturing process or after the product is manufactured.

It is an object of the present invention to provide a vapor-deposited film having excellent gloss and reflectivity.

In order to achieve the above object, the present invention has a secondary structure, that is, a polypropylene biaxially stretched film (A) and a polypropylene film (A) laminated on at least one side thereof. The ethylene component is 2 to 15 wt%, the other main component is propylene, and the birefringence is 7 x 10'' or less.

A polymer film (B) whose surface layer has an atomic composition ratio (number of nitrogen atoms/number of carbon atoms) of 0.005 to 0.010.

A vapor deposited layer (
C), and the surface gloss of this vapor deposited layer (C) is 30.
The gist is a vapor-deposited film with a value of 0 or more.

Polypropylene biaxial stretching (hereinafter [0P
The film (A) (abbreviated as PJ) is a biaxially stretched film stretched by a well-known stretching method such as simultaneous, biaxial, or sequential biaxial stretching, and is a polypropylene film.

A commonly used polypropylene homopolymer.

A blend of α-olefin homopolymers and copolymers represented by ethylene and butene-1 in an amount not exceeding 50 wt % based on polypropylene is used. The thickness of the OPP film is not particularly limited, but preferably 5 to 150 microns.

The ethylene component in this invention is 2 to 15 wt%.

Others are polymer films whose main component is polypropylene (B
),! : is ethylene propylene random copolymer (
Hereinafter, ethylene propylene block copolymer (hereinafter referred to as ``EPBCj''), a blend thereof, and ethylene.

It refers to a film made of a blend with polypropylene, and the preferred ethylene content is 3 to 10 wt%. BPRC is preferred as the copolymer.

It may also be a terpolymer of α-olefin such as butene-1, ethylene, and propylene. Further, when blending polypropylene, it is preferably 10 wt% or less.

In the case of a blend of gpRc, BPBC, and polyethylene, the ethylene component is the ethylene component of EPRC.

Refers to the total ethylene component including the ethylene component of EPBC and polyethylene. If the ethylene content is less than 7% 2W, it is difficult to obtain the adhesive strength of the deposited film according to the present invention.
If the ethylene component exceeds 15 wt %, it is difficult to maintain the surface gloss of the vapor-deposited surface according to the present invention, and the composite cannot be uniformly composited.

So-called lamination failure has occurred. Also.

Blending polypropylene reduces the adhesive strength of the deposited film.

The ethylene component is normally determined by the calibration M method using an infrared absorption spectrum based on the absorbance ratio of 1170 cm-1 caused by polypropylene and 715-725 cm or 730-735 cm-1 caused by copolymerized ethylene. The ethylene component referred to in this invention can be determined by the presence or absence of absorption in the infrared absorption spectrum from 730 to 765 cm''.

It can also be determined by the presence or absence of absorption between 715 and 725 cm-'.
, this absorption band cannot be used.

The thickness of the layer having this composition is not particularly limited.

The thickness is preferably 20% or less of the thickness of the polypropylene film layer (A).

The birefringence of the layer made of the above-mentioned specific ethylene component of this invention is as follows: 7. Ox 10-3 or less, preferably.

Must be no larger than 5x10'. The measurement was carried out using an Atsube refractometer in the longitudinal stretching direction (hereinafter abbreviated as ny) and the transverse stretching direction (hereinafter abbreviated as n).

nX-ny was defined as birefringence. Methyl salicylate was used as a film mounting solution during measurements.

If the birefringence exceeds 7 x 10-3, a satisfactory adhesive strength of the deposited film cannot be obtained. Birefringence is a factor that represents the degree of orientation of a polymer, and as the degree of orientation increases, the adhesive strength of the deposited film decreases. As factors that determine the degree of orientation, not only the stretching ratio but also the film temperature during stretching and raw material characteristics are important. That is, by raising the film temperature during stretching as high as possible, above the melting point of the laminated polymer (B) (generally 110 to 140°C for ethylene propylene copolymer and ethylene), the laminated polymer film (B)
) the degree of orientation is markedly reduced. Therefore, in order to obtain the degree of orientation of the present invention, it is necessary to stretch at a temperature close to the melting point of the base polypropylene resin (A) (about 161°C for crystalline polypropylene), that is, at a film temperature of 155 to 160°C.

This requirement may be satisfied in the heating section of the transverse stretching in sequential biaxial stretching, and in the heating section in simultaneous biaxial stretching.

Also, the raw material characteristics of the laminated polymer (B), especially melt intex, ethylene component ratio 1 polymerization method (random).

The laminated polymer (B block, blend)
) The degree of orientation varies greatly. That is, in order to lower the degree of orientation, the tart index and ethylene component ratio should be increased (preferably melt index 5 g/l, 0 minutes or more, ethylene component ratio 40% or more).

It is preferable to use a random copolymer. Therefore, it is necessary to select raw material properties and stretching conditions depending on the desired degree of orientation.

The ratio of the number of nitrogen atoms N to the number of carbon atoms C on the film surface (usually a layer within 1ooX depth from the surface) of the layer made of the specific ethylene component of this invention.

That is, N/Cid should be 0.005 to 0.10; preferably Ha002 to 0.05. If it is smaller than this range, the adhesive strength of the vapor-deposited film will be poor, and if it exceeds this range, the slippage of the film will be very poor, resulting in poor workability in the winding process, etc.

If film VC/wa occurs, film blocking may occur.

In addition, it refers to the value determined by the linear method of the ratio N/C of the number of nitrogen atoms to the number of carbon atoms.

The surface of the film was measured using an ESCA spectrometer model ES200 manufactured by Kokusai Electric Co., Ltd. under the following conditions.

Excited X-ray: A, l? KH2 line (1486,6eV
) X-ray dose crab 10kV 20mA Temperature = 20℃ Kinetic energy correction: The kinetic energy value of neutral carbon (≧cH2) was set to 1202. Adjusted to O eV.

From the obtained spectrum, the area ratio of the c1s peak to N1s peak was defined as the ratio (number of nitrogen atoms/number of carbon atoms), or the value of N/C.

The vapor-deposited layer (C) is applied on the surface portion in which the birefringence of the layer made of the specific ethylene component of this invention and the atomic composition ratio N/C are within the above range. When both surfaces of the film are within this range, the vapor deposition may be performed on one surface or only one surface. It goes without saying that if only one side of the film falls within this range, the film will be deposited on that surface. The metal to be vapor-deposited is not particularly limited, but aluminum and zinc are usually preferably used. The vapor deposition method is not particularly limited either.
Well-known methods such as electrothermal heating fusion vapor deposition, ion beam vapor deposition, sputtering, or ion blating can be used. The thickness of the deposited film is usually 100~
A range of 5000 A is preferably used.

The surface gloss of the vapor deposited layer (C) is expressed as GS (60) based on J-TS-Z-8741 method 2, and the higher the value, the better the gloss. do.

In order to make the surface gloss of the vapor deposited layer (C) 300 or more, the surface gloss of the layer (B) made of a specific ethylene component must be 90.
It is necessary to keep it above. At this time, the surface roughness Ra is 0
It is 15μ or less. Ra is the center line average roughness (cutoff value 0.25 mm), Jl:S-B 0
601. Such surface gloss can be achieved by keeping the ethylene component within the above range.

Next, the method for manufacturing the film of this invention will be explained.

After simultaneously melt extruding a layer consisting of polypropylene and a specific ethylene component into a sheet.

It is cooled and solidified, further heated, and stretched in the longitudinal and transverse directions. The layer consisting of a specific ethylene component is not limited to the above-mentioned coextrusion, but - before axial stretching.

Alternatively, it may be applied before or after biaxial stretching. This ethylene component is adjusted to have a desired surface gloss level.

The film obtained in this way is placed in a nitrogen atmosphere, and the film temperature is 60 to 100°C, preferably 50 to 90°C.
300 of electrical energy applied to that particular surface while maintaining
．． 0-6000 Jim2. Desirably 4000-55
Corona discharge treatment is performed at 00 J/m2. By such a method, the N/C can be made into a film with a specific range of surfaces. This treated film is set in a vacuum deposition apparatus, and aluminum or the like is deposited on the treated surface.

This invention is characterized by the above-described laminated film, but an inorganic filler may be added to the polypropylene base layer of this film to create a film with internal voids. Namely.

By adding an inorganic filler and stretching, many voids are generated inside the film, resulting in a film with excellent flexibility. Examples of inorganic fillers include 2.

These include diatom inhibitors, calcium carbonate, kaolin, carunium sulfate, and talc.

In this invention, 9% of the base material layer is made of polypropylene.
To the extent that antioxidants, heat stabilizers, ultraviolet absorbers, lubricants, pigments, antistatic agents, etc. are usually added to either or both layers of the layer consisting of a certain ethylene component, as necessary,
Further, they may be added within a range that does not impair the characteristics of the present invention.

As mentioned above, the OPP-based vapor deposited film of the present invention has a specific ethylene component, birefringence, and atomic composition ratio, that is, an ethylene component of 2 to 15 wt% (preferably 3 to 10 wt%). ), birefringence 7.0x10-3 or more T(
(preferably 5.0x10-' or less).

1, +7cJ:fSO,005~0. IO (preferably 0.01-0.05), and the surface gloss of the vapor deposited layer is 300 or more.
The adhesive strength of the deposited film is strong, resulting in excellent wear resistance and friction resistance.

Furthermore, it has excellent gloss and reflectivity.

Such vapor-deposited films are used for general wrapping materials, paper, laminated materials for metals, industrial materials such as insulation materials and wall materials, and fields that require simple vapor-deposited film adhesive strength such as labels and stickers. It can be widely used for

Note that the effects of this invention were evaluated based on the first-order criteria.

(1) Vapor-deposited film adhesion strength A commercially available cellophane adhesive tape (manufactured by Chihan Co., Ltd.) was attached to the vapor-deposited surface and peeled off at 180°C. Based on the adhesion area of the vapor-deposited metal, it was evaluated using the 6 levels (index) shown in the table below. .

Table 1 Next, the present invention will be described in detail based on examples.

Example 1. Comparative Example 1 Commercially available polypropylene pellets (melt index 2 g/l 0 min, isotactic degree 97.3%) were put into one extruder and ethylene component 5 wt% (7) IICP
RC (Melt Intex 65 g/10 minutes) was supplied to separate extruders and melted and coextruded into a sheet at 270°C, which was then wound around a cooling drum with a surface temperature of 45°C to cool and solidify. While heating this sheet to 125℃,
It was stretched 45 times in the longitudinal direction. moreover.

It was guided into a stenter and stretched 9 times in the width direction at a stretching temperature of 160°C, then heat treated at 160°C while giving a 5 factor relaxation in the width direction, and then slowly cooled to a thickness of 20μ (polypropylene base layer 18μ). I made a film of. Place this film in a nitrogen atmosphere.

One side of the film was corona discharge treated with an amount of electrical energy of 1000-6000 J/m2.

By changing the amount of electrical energy, films with different N/C values as shown in Table 2 could be produced. These films were placed into a vacuum deposition apparatus, and a full 9nium MM film having a thickness of 600 angstroms was deposited on the corona discharge treated surface.

Comparative Example 2 Coextrusion raw material is ethylene component 20wt% (7) EPBC
A vapor-deposited film was obtained in exactly the same manner as in Example 1, except that the melt index was 7, 5 g/l, 0 minutes.

Comparative Example 6 A vapor-deposited film was obtained in exactly the same manner as in Example 1, except that the coextrusion raw material was EPRC containing 1 g of ethylene (Melt Intex: 8.0 g, 710 minutes).

Comparative Example 4 EPBC with 8 wt% ethylene component as a coextrusion raw material (
melt index 2.5 g/io min) and commercially available polypropylene (melt index 2 g/l 0 min).

A vapor-deposited film was obtained in exactly the same manner as in Example 1, except that a 1:1 blend with an isotactic degree of 97.3% was used and the transverse stretching temperature was 150°C.

The properties of these deposited films are summarized in Table 2.

As shown in Table 2, the adhesive strength of the deposited film in Example 1 was strong, and the film had excellent metallic luster and reflectivity. When the atomic composition ratio N/C is less than the range of the present invention (Comparative Example 1), the adhesive strength of the deposited film is low;
) had a large surface roughness and was matte.

In addition, those with an ethylene component of less than 2 wt% of the present invention (Comparative Example 3) and those with birefringence exceeding 7.0x10"-3 (Comparative Example 4) both have low adhesion strength of the deposited film. I could only get it.

Patent Applicant Toshi Co., Ltd. Procedural Amendments Director of the Patent Office Kazuo Wakasugi 1, Indication of the case Patent Application No. 9964 of 1982, 2 Name of the invention Vapor-deposited film 3, Person making the amendment Relationship with the case Patent applicant address: 2-2-4 Nihonbashi Muromachi, Chuo-ku, Tokyo Date of amendment order Voluntary 5 No number of inventions increased by amendment 6 1 Detailed description of the invention in the specification subject to amendment 1 ) "Component ratio 40%" on page 7, line 1 of the specification is corrected to "component ratio 4.0%."

(2) Same page 7 line 9 ro, 02~0.05J ro, 01~0.05''
and correct it.

Claims (1)

[Claims] A biaxially stretched polypropylene film (A) and an ethylene component 2 laminated on at least one side of the film (A).
~i 5 wt% and the rest is propylene as the main component. Birefringence is 7 x i O”-3 or less, and the atomic composition ratio of the surface layer (number of nitrogen atoms/number of carbon atoms) is 0.0
It consists of a polymer film (B) of 0.05 to 0.10 and a vapor deposited layer (C) deposited on the surface of the polymer film (B), and the surface gloss of the vapor deposited layer (C) is 6.00. A vapor deposited film characterized by the above.