JPS5949963A - 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 The present invention relates to a vapor-deposited film, more specifically a biaxially oriented polypropylene (hereinafter referred to as r) on which a metal such as aluminum is vapor-deposited.
(abbreviated as OPPJ) film.

BACKGROUND ART Conventionally, films obtained by subjecting OPP films to surface treatment and depositing metals such as aluminum (hereinafter referred to as "vapor deposition") have been widely used for general packaging purposes. However, in the conventional method, that is, the method using only surface treatment, the vapor deposition film obtained does not have sufficient vapor deposition transfer strength, and the vapor deposited film is easily damaged and peeled off due to abrasion. Furthermore, if the vapor deposition adhesive strength is not sufficient, the vapor deposited film may be peeled off due to blocking under high temperature and high humidity conditions (especially in summer).

In view of these circumstances, an object of the present invention is to provide an OPP deposited film that has strong adhesion and is sufficiently resistant to abrasion and friction during the manufacturing process or after it is made into a product. .

In order to achieve the above object, this invention has the following composition: an OPP film (A) laminated on at least one side of this film (A), with an ethylene component of 5 to 50% and propylene as the main component. , surface roughness Ra value is 0.2
Polymer 5-member film (B) with a diameter of ~1.5μ and an atomic composition ratio (number of nitrogen atoms/number of carbon atoms) of 0.005 to 0.10
and a vapor deposited film (C) deposited on the surface of this polymer film (B).

The OPP film (Δ) in this invention is a biaxially stretched film that has been stretched by a well-known stretching method such as simultaneous biaxial or sequential biaxial stretching, and is a polypropylene homopolymer that is used as polypropylene for tπ, and For this purpose, a blend of α-olefin homopolymers or copolymers represented by ethylene and butene-1 in an amount not exceeding 50% based on polypropylene is used.

The thickness of the OPP film is not particularly limited, but 1
0 to 150μ is preferred.

In this invention, the polymer film (B) having an ethylene component of 5 to 50% and the other main component being polypropylene is an ethylene propylene block copolymer (hereinafter referred to as rEPBc).
abbreviated as J), polyethylene, polypropylene, E
Refers to a film consisting of a blend of two or three PBCs, preferably low density polyethylene and EPBC.
It is a film made of a blend of A particularly preferred blending ratio of the ethylene component is 20 to 40%. In the case of a blend containing polyethylene and EP)3C, the ethylene component refers to the total ethylene component, which is the sum of the ethylene component in EPBC and polyethylene. If the ethylene content is less than 5%, it is difficult to obtain the specific surface roughness and adhesion strength of the deposited film referred to in this invention, and if the ethylene content exceeds 50%,
It is difficult to maintain the surface roughness referred to in this invention, and the composite cannot be uniformly composited, resulting in so-called lamination failure.

The ethylene component can normally be determined by the calibration curve method using an infrared absorption spectrum based on the absorbance ratio at 1j70 cm and 720 cm. The ethylene component referred to in this invention has an infrared absorption spectrum of 720 cm.
It can be determined by the presence or absence of absorption at -'. However, random copolymers cannot absorb 720 cm-'. Low ethylene content.

If this is not the case, the absorption at 720 cm-' may not be a complete single absorption but may be in the form of a circumferential absorption, but even in this case it is considered that there is an absorption. Note that the thickness of the layer made of this composition is not particularly limited, but is preferably 0.5 to 25 μm.

The surface roughness l? of the layer made of the above-mentioned specific ethylene component of this invention? a is 0.2 to 1.5 μ, preferably Ra09
It is preferably in the range of 3 to 1.0μ. The surface roughness can be achieved within such a range by keeping the ethylene component within the above range, but it may also be possible by further using a method of developing embossed 9-spherulites. Here, the surface roughness 11a refers to the center line average roughness (cutoff value 0.25M), and is based on JIS, -BO
601.

The ratio of the number of nitrogen atoms N to the number of carbon atoms C, that is, N/C, on the film surface (layer within 100 depth from the current-carrying surface) of the layer made of the specific ethylene component of this invention is 0. .005-0.10, preferably 0°02-0.0
Must be 5. If it is smaller than this range, the adhesion strength of the vapor-deposited film will be poor, and if it exceeds this range, the slippage of the film will be very poor, the workability in the winding process etc. will be poor, and the film may wrinkle. , film blocking may occur.

Note that the ratio N/C between the number of nitrogen atoms and the number of carbon atoms refers to a value determined by the following method.

E'SCA spectrometer ES200 manufactured by Kokusai Denki ■
Using a mold, the film surface was measured under the following conditions.

Excited X-ray: Ajl! Kα radiation (1486,6e
V) X-ray output: 10kV 20mA temperature
Degree: 20°C Kinetic energy correction: The kinetic energy value of neutral carbon (,:: CH2) was adjusted to 1202, Oe V.

From the obtained spectrum, the area ratio of the C-S peak and the N-S peak was defined as the ratio (number of nitrogen atoms/number of carbon atoms), that is, the value of N/C.

The vapor deposition layer (C) is formed on the surface of the layer made of the specific ethylene component of the present invention whose surface roughness Ra and atomic composition ratio N/C are within the above ranges. When both surfaces of the film are within this range, the vapor deposition may be performed on both surfaces or only on one surface. It goes without saying that if only one side of the film is within this range, the vapor 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 also particularly limited to J', electric heating melt vapor deposition method, and ion beam vapor deposition method.

A sputtering method, an ion blating method, or the like can be used. The thickness of the deposited film is tπ100
A range of 5,000 to 5,000 people is preferably used.

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

A layer consisting of polypropylene and a specific ethylene component is simultaneously melted and extruded into a sheet, then 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 coextrusion, but -
It may be applied before axial stretching, or before or after biaxial stretching.

The original ethylene component is used after adjusting the surface roughness to a desired value due to its matting properties.

The film obtained in this way is placed in a nitrogen atmosphere, and the film temperature is 30 to 100°C, preferably 50 to 90°C.
300 of electrical energy applied to that particular surface while maintaining
0~60'00J/n (preferably 4000~・550
Corona discharge treatment is performed at 0 J/%. By such a method, it is possible to form a film with a surface having N/C in a specific range.

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 laminated film as described above, but if an inorganic filler is added to the polypropylene base layer of this film to create a film with internal voids, it will be even more excellent. You can increase the effect. In other words, by adding an inorganic filler and stretching, many voids are generated inside the film, resulting in a film with excellent flexibility.On the other hand, since the adhesive strength of the vapor-deposited film is high, it is difficult to roll the film. Even with the application ζ, the deposited film does not fall off, and the deposited film has a good texture and excellent flexibility.

The same result can be obtained even if the vapor deposition step is performed after rolling. The film forming method in this case is to add 5 to 60%, preferably 1%, of an inorganic filler (for example, diatomaceous earth, calcium carbonate, kaolin, calcium silicate, talc, etc.) to polypropylene.
The mixture is kneaded in an amount of 5 to 45% in advance, made into a stretched film in the same manner as above, and further made into a vapor-deposited film. However, since the flexibility varies depending on the stretching temperature and stretching ratio, a film with desired flexibility and texture can be obtained by combining the amounts added. If the filler concentration is below this range, the flexibility will be poor, and if it exceeds this range, uneven kneading will likely occur, resulting in uneven film and tearing during stretching.

An inorganic filler may be added to a layer consisting of a specific ethylene component in a similar manner, but the amount added is preferably 5 to 30% from the viewpoint of adhesive strength of the deposited film, and in this case the ethylene component is 2%.
Particularly preferred is 5-40%.

In this invention, a group jtAF consisting of polypropylene
(t) A layer consisting of a specific ethylene component, or both layers may contain an antioxidant, a heat stabilizer, an ultraviolet absorber, etc. as required. ? I agents, pigments, dyes, antistatic agents, etc. may be added to the extent that they are normally added, and to the extent that they do not meet the characteristics of this invention.

As mentioned above, the OPP vapor-deposited film of the present invention has a specific ethylene component 2 surface roughness and atomic composition ratio, that is, an ethylene component of 5 to 50% (preferably 20 to 40%).
, Rag, 2 to 1.5 μ (preferably 0.3 to 1
．． Since the OPP film has an N/C in the range of 0.005 to 0.10 (preferably 0.01 to 0.05), the adhesive strength of the deposited film is strong, and it has excellent wear resistance and friction resistance. It produces excellent effects and also has matte properties. Such vapor-deposited films are used for general packaging materials, paper, laminated IFA materials for metals, industrial materials such as insulation materials and wall materials, and even labels and stickers that require strong adhesion strength for vapor-deposited films. It can be used in a wide range of fields.

Note that the effects of this invention were evaluated based on the following criteria.

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

Table 1 (2) Blocking width 3 cm x length lQ cm sample film length 4 cm
After stacking 6 pieces over m length and leaving them in an atmosphere of 85% R11 at 40°C for 5 days under a load of 3 kg, the force required for shear peeling is measured using a tensile tester. 'The smaller the number, the less blocking it means.

(3) Glossiness JI: Based on S-Z ~ 8741 method 2 <GS (60°)
It means that the lower this value is, the better the matting effect is.

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

[Example 1. Comparative Example 1.2 Commercially available polypropylene pellets (Null l-Indef 21
2g/10min,'? Ikkuchitsu degree 97, 3%)
into one extruder, a copolymer of 30% ethylene component and 70% propylene component (melt index jg/10
) were respectively supplied to separate extruders and melt-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. Heat this sheet to 125℃
The film was stretched 4.5 times in the longitudinal direction while being heated to . moreover,
It was introduced into a stenter and stretched 9 times in the width direction at a stretching temperature of 160°C, and then stretched at 1.60°C while giving 5% relaxation in the width direction.
This was heat-treated and slowly cooled to form a film with a thickness of 35 μm (polypropylene base material W: 132 μm).

This film was placed in a nitrogen atmosphere and
One side of the film was subjected to corona discharge treatment with an electrical energy amount of 0 J/rd.

By changing the amount of electrical energy, it was possible to produce films with various N/C values as shown in Table 2. These films were placed in a vacuum deposition apparatus, and the aluminum deposited film was deposited on the corona discharge treated surface to a thickness of 600 Å.

C Comparative Example 3] Coextruded raw material contains 4% ethylene component and 96% propylene component
% copolymer (melt index 7 g/10 min), a vapor-deposited film was obtained in exactly the same manner as in Example 1.

[Example 2] Adding 28% calcium carbonate to polypropylene with 1rAKt group
A vapor deposited film was obtained in exactly the same manner as in Example 1 by adding %. The film thickness in this case was 55μ (polypropylene base material R52μ).

The properties of these deposited films are summarized in Table 2.
Table 2 Vapor deposited film film properties
7. . Kaa. II.

(%) Ra N/C thickness Adhesive strength Example 1 30 0.6B 0.04j O354,5~
! Comparative example 1 30 0.680. As shown in Table 2 of OOl-0353, in Example 1, the adhesive strength of the deposited film was strong and the film had a matte metallic luster.

When the atomic composition ratio N/C is less than the range of this invention (Comparative Example 1), the adhesive strength of the deposited film is low, and when it exceeds the range (Comparative Example 2), wrinkles occur during winding or rewinding. caused blocking. In addition, those with a small ethylene content of 4% (ratio - 3) had low surface roughness, did not increase the adhesive strength of the deposited film, had high gloss, and had poor matte properties.

In Example 2, an inorganic filler was added to the polypropylene of the base layer to create a film with excellent flexibility, so this vapor-deposited film had excellent matte properties and adhesive strength of the vapor-deposited film, and surprisingly, it was easy to process by rubbing. Even after applying this method, the deposited film did not come off and the film had a textured, leather-like appearance.

S Agent: Patent Attorney Takehiko Matsumoto

Claims (1)

[Claims] +l) Polypropylene biaxially stretched film (A> and
Laminated on at least one side of this film (A), the main component is 5 to 50% ethylene and the rest is propylene,
The surface roughness Ra value is 0.2 to 1.5μ, and the atomic composition ratio (number of nitrogen atoms/number of carbon atoms) is 0.00゛5 to 0.10.
polymer film (B), and this polymer film (B)
A vapor-deposited film consisting of a vapor-deposited layer (C) vapor-deposited on the surface of the vapor-deposited film.