JPH0659720B2 - Matte moisture-proof film - Google Patents

Description

Description: TECHNICAL FIELD OF THE INVENTION The present invention relates to a matte moisture-proof film having a matte metallized surface and having excellent moistureproofness.

[Prior art]

It is conventionally known to deposit a metal on the surface of a film in order to enhance the decorating property.

For example, JP-A-59-192563 discloses forming a metal vapor deposition layer on a film containing an ethylene-propylene block copolymer or an ethylene-propylene random copolymer as a main component.

However, in the film obtained by the present invention, although the moisture-proof property is improved by the metal vapor deposition layer, there is a drawback that the moisture-proof property is not sufficient.

[Object of the Invention]

INDUSTRIAL APPLICABILITY The present invention has a matte matte metal-deposited surface and is excellent in moisture resistance, that is, the water vapor transmission rate P is 1 (g / m ^2).
It is an object of the present invention to provide a matte moisture-proof film having the following moisture resistance, which is excellent in handleability such as abrasion resistance and blocking resistance.

[Structure of Invention]

The present invention which achieves the above object is one of resins selected from petroleum resins substantially free of polar groups and terpene resins substantially free of polar groups per 100 parts by weight of polypropylene.
The main component is an ethylene-propylene block copolymer containing 20 to 40% by weight of an ethylene component having a surface roughness Rmax of 0.15 to 20 on at least one side of a film (I) in which 5 to 100 parts by weight of at least one species are mixed. The film (II) layer is laminated, and a metal vapor deposition layer is further formed on the film (II) layer, and the glass transition temperature of the film (I) is 10 to 50 ° C. It is characterized by.

In the present invention, the polypropylene used for the film (I) is not particularly limited, but the isotactic index (II) is 93% or more, and the intrinsic viscosity [η] measured in tetralin is 0.8 to 4 (Dl / g), especially 1.0 ~
The range of 2.2 (dl / g) is preferable.

A second component other than propylene, such as ethylene, butene,
Although hexene, maleic anhydride, etc. may be randomly, block- or graft-copolymerized, a homopolymer is preferable for the purpose of the present invention.

The polypropylene may contain known additives such as a crystal nucleating agent, an antioxidant, a heat stabilizer, a slip agent, an antistatic agent, an antiblocking agent, a filler, a viscosity modifier, and an anticoloring agent. good.

The petroleum resin containing no polar group are mixed in such a polypropylene substantially, a hydroxyl group (-OH), carboxyl group (-COOH), a halogen group (-X), sulfone group _(-SO 3 Y, Y is H , Na, 1/2 Mg, etc.) and petroleum resins having no polar group consisting of these modified compounds, that is, mainly cyclopentadiene-based hydrocarbons or higher olefin-based hydrocarbons directly derived from petroleum-based unsaturated hydrocarbons. Although the resins used as raw materials, hydrogenated resins obtained by adding hydrogen to these resins and having a hydrogenation rate of 80% or more, preferably 95% or more are particularly preferable in the case of the film of the present invention.

Further, the glass transition temperature Tg of this petroleum resin is 50 ° C or higher,
It is preferably 76 ° C. or higher for the film of the present invention.

As this typical resin, for example, a high Tg fully hydrogenated alicyclic petroleum resin such as polydicyclopentadiene having a hydrogenation rate of 95% or more at a Tg of 76 ° C. or more is particularly suitable.

As the terpene resin which does not substantially contain a polar group, a hydroxyl group, an aldehyde group (-CHO), a ketone group (> C =
O), carboxyl group, halogen group, sulfone group, etc.
And a terpene resin substantially composed of a modified product thereof having no polar group, that is, a hydrocarbon having a composition of (C ₅ H ₈ ) _n and a modified compound derived therefrom.

n is a natural number of about 2 to 20.

The terpene resin may be referred to as a terpenoid as another name.

Typical compounds include pinene, dipentene, carene, myrcene, ocimene, limonene, terpinolene, terpinene, savirene, tricyclene, bisabolen, zingiperene, santalen, camphorene, millen, totalene, etc., and hydrogen in the case of the film of the present invention. Is added, and the hydrogenation rate thereof is preferably 80% or more, preferably 90% or more, and hydrogenated β-pinene and hydrogenated dipentene are particularly preferable.

In the present invention, it is important to use the hydrogenated resin as described above, and the bromine number is 10 or less, preferably 5 or less, more preferably 1 or less.

The film (I) in the present invention is the above polypropylene.
5 to 100 parts by weight, preferably 10 to 29 parts by weight of 100 parts by weight of one or more resins selected from petroleum resins substantially free of polar groups and terpene resins substantially free of polar groups. Film and the glass transition temperature T
g is 10 to 50 ° C, preferably 20 to 40 ° C.

When the mixing amount of the above-mentioned resin which does not substantially contain a polar group exceeds 100 parts by weight, preferably 29 parts by weight, not only the mechanical, thermal and chemical properties of the film of the present invention are deteriorated, but also the above-mentioned resin is A film (I) bleeding out on the surface of the film (I) containing an ethylene-propylene copolymer as a main component (I
I) Worse the adhesion of the layers.

Further, the film (I) has an increased oil permeability of vegetable oils, mineral oils, etc., and oil seeps out on the surface of the film to further reduce the interlayer adhesive force in the film of the present invention.

When the amount of the above resin mixed is 5 parts by weight, preferably less than 10 parts by weight, the glass transition temperature T of the film (I) is
Excellent moisture resistance cannot be obtained regardless of g.

As described above, the effect of the present invention becomes remarkable especially when the amount of resin mixed is as small as 10 to 29 parts by weight.

Further, the glass transition temperature Tg is less than 10 ° C, preferably 20
When the temperature is lower than 0 ° C, the excellent moistureproof property, which is the object of the present invention, is not achieved. On the other hand, when the Tg value exceeds 50 ° C, preferably 40 ° C, the mechanical properties of the film of the present invention are remarkably poor. It becomes a vine. In the present invention, the molecular chains in the film (I) may or may not be oriented, but the amount of resin added may be reduced to increase Tg, and further, mechanical properties and optical properties It is preferable that the molecular chains are oriented from the viewpoint of low thermal properties.

In particular, the film is biaxial and balanced on the inner surface of the film, that is, the absolute value of birefringence is 0.025 or less, preferably
It is 0.015 or less.

In addition, the value obtained by subtracting the refractive index in the thickness direction from the half of the sum of the refractive index in the vertical direction and the refractive index in the horizontal direction, which is a measure of film surface orientation, is in the range of 0.006 to 0.012. It is preferable in terms of cleavage and oil resistance.

Further, the crystallinity of the film (I) is 50% or more, preferably
60% or more is desirable, the substrate film thickness is 0.5
.About.1000 .mu.m, preferably 4-250 .mu.m, more preferably 8-60 .mu.m.

The film (I) in the present invention is a mixture of polypropylene with at least one kind of petroleum resin substantially free of polar groups or terpene resin substantially free of polar groups as described above. When another resin is added to the resin, its amount is preferably less than 30 parts, preferably less than 20 parts.

Other resins include polyolefin other than polypropylene, petroleum resin containing a polar group, terpene resin containing a polar group, and the like.

In the present invention, the film (II) mainly composed of an ethylene-propylene block copolymer laminated on at least one side of the film (I) has a surface roughness Rmax of 0.15 to 20.
The ethylene-propylene block copolymer may be used alone, or other polymer may be added in an amount of 5 to 35% by weight.

When the ethylene-propylene copolymer is a block copolymer, the moisture-proof property, the adhesive property with the metal vapor-deposition layer, and the matte property which are the objects of the present invention can be advantageously improved for the first time.

Such other polymers include ethylene-propylene random copolymers, polyethylene, polypropylene, blends of polyethylene and polypropylene, ethylene-
Examples thereof include blends of propylene random copolymer with polyethylene and / or polypropylene.

The ethylene-propylene block copolymer constituting the film (II) layer contains 20 to 40% by weight of an ethylene component.

Here, the ethylene component means that when a polymer other than the ethylene-propylene block copolymer is added,
It refers to the total ethylene component including the ethylene component in other polymers.

When the ethylene component is less than 20% by weight, the above-mentioned specific surface roughness cannot be obtained, and it is difficult to obtain sufficient adhesive strength with the metal vapor deposition layer.

Further, when the ethylene component exceeds 40% by weight, it becomes impossible to obtain the above specific surface roughness.

If the surface roughness Rmax of the film (II) layer containing an ethylene-propylene block copolymer as a main component is less than 0.15 μm, preferably less than 0.18 μm, not only the matting effect is deteriorated but also excellent moisture resistance is obtained. I can't get it.

On the other hand, if the surface roughness exceeds 20 μm, preferably 2 μm, not only a high-quality matte feeling cannot be obtained, but also excellent moisture resistance cannot be obtained.

The metal vapor deposition layer formed on the film (II) is not particularly limited as the metal, and may be Al, Zn, Al-Zn.
Alloys, Ni, Cr, Co, etc. are used, but Al and Zn are preferable.

The thickness of the vapor deposition layer is 100-2000Å, preferably 200-1000
Å, and this vapor deposition layer is formed by a well-known method such as an electrothermal heating fusion vapor deposition method, an ion beam vapor deposition method, a sputtering method, or an ion plating method.

Next, the method for producing the matte moisture-proof film of the present invention will be described.

A raw material (I) obtained by adding the above-mentioned specific petroleum resin and / or terpene resin to polypropylene and a raw material (II) containing an ethylene-propylene block copolymer as a main component are supplied to different extruders at different resin temperatures. After melting at a temperature not exceeding 240 ° C, preferably at a temperature of 180 to 220 ° C, the mixture is discharged from the two-layer composite spinneret (I) / (II) to obtain a two-layer laminated unstretched film.

At this time, if the resin temperature exceeds 240 ° C., preferably 220 ° C., not only the moisture-proof film aimed at by the present invention cannot be obtained, but also the resin is thermally decomposed or scattered.

The surface temperature of the cooling drum varies depending on the relationship with the subsequent steps, but it is preferably in the range of 60 to 120 ° C, preferably 95 to 110 ° C.

Subsequently, the cast film is uniaxially oriented, biaxially oriented, or multiaxially oriented, or heat-treated to form a specific surface roughness on the film (II) layer, and the glass transition of the film (I). Bring the temperature to a specific range.

In this case, any known method such as roll stretching, rolling, tenter stretching, disc stretching, belt stretching and a combination thereof can be used as a method for imparting orientation.

At this time, the Tg value of the film (I) and the film (I having an ethylene-propylene block copolymer as a main component)
It is necessary to orient the layer so that the surface roughness of the layer I falls within the above-mentioned specific range. For example, in the case of sequential biaxial stretching, the initial longitudinal stretching ratio is 6 to 10 times and the transverse stretching ratio is about 6 to 12 times. Is good.

Then, the obtained laminated film was filled in a vacuum vapor deposition apparatus, and aluminum or the like was vapor-deposited on the surface of a film (II) layer containing ethylene-propylene copolymer as a main component,
The moisture-proof film of the present invention can be obtained.

Almost no change in shrinkage was observed in the laminated film before and after vapor deposition.

In the present invention, the surface of the film (II) layer containing the ethylene-propylene block copolymer as a main component laminated prior to metal vapor deposition may be subjected to corona discharge treatment in air. In the case of the invention, particularly in the presence of carbon dioxide gas, nitrogen gas, etc., corona discharge or plasma treatment is carried out in an atmosphere substantially free of oxygen, and an imino-type and / or amino-containing compound is formed on the outermost surface layer, for example, 100 Å from the surface. It is also possible to introduce a type of nitrogen atom.

As a typical surface treatment method, for example, Japanese Patent Publication No. 57-3
As shown in No. 0,854, etc., in an atmosphere of a mixed gas of nitrogen and carbon dioxide (N ₂ / CO ₂ = 100/0 to 50/50 volume ratio), and the oxygen concentration is 0.1 vol% or less. Corona discharge treatment in the atmosphere of.

Alternatively, a method in which various gases are placed in a plasma state to chemically change the film surface, for example, JP-A-59-98,140,
There is a method of forming a surface activated layer by chemical treatment.

By such surface treatment, not only the adhesive strength between the film (II) and the vapor-deposited metal layer can be increased, but also the moisture resistance can be improved.

Further, according to the present invention, a thin polypropylene layer having a thickness of 0.2 to 3 μm is interposed between a film (II) layer and a film (I) layer containing an ethylene-propylene block copolymer as a main component. If added, it helps to further improve the matte effect and moisture resistance of the metal surface.

〔The invention's effect〕

As described above, according to the present invention, a film (I) having an ethylene-propylene block copolymer as a main component is laminated on at least one surface of a film (I) in which polypropylene is mixed with a specific resin, Moreover, the surface roughness Rmam of this layer is set to 0.15 to 20 μm, and in the laminated film in which the metal is vapor-deposited on the film (II) layer, the glass transition temperature Tg of the film (I) is 10 to 50 ° C. Tg (0 ° C.), which is extremely high, the following effects can be obtained.

(1) Excellent moisture resistance is obtained by the film (I) layer and the vapor-deposited metal layer, and the water vapor permeability is 1.0 or less, preferably 0.5 (g / m ² days / 20 μm) or less. .

(2) Since the film (II) layer containing an ethylene-propylene block copolymer as a main component has a surface roughness of Rmax = 0.15-20, an excellent matting effect can be obtained for a metal vapor deposition layer.

Therefore, the film of the present invention is rich in drawability and imparts a matte high-class image.

(3) In the present invention, the metal layer is vapor-deposited on the film (II) layer containing ethylene-propylene copolymer having a specific surface roughness as a main component, so that the vapor-deposited metal layer is formed relatively uniformly. Therefore, blocking of metal vapor deposition surfaces can be prevented without adding a slip agent.

(4) Further, the metal vapor-deposited surface is hard to peel off, and a metal vapor-deposited surface having excellent abrasion resistance is obtained.

(5) Metallized surface, especially in the case of Al, for example 40 ℃, 60RH%
It also has excellent water resistance below, and can be made to last long without losing the deposited layer.

The definitions of the terms used in the present invention and the measuring method will be described.

(1) Water vapor transmission rate According to JIS Z-0208, measured at 40 ° C and 90% RH g / m ² days
/ Expressed in film thickness units.

(2) Intrinsic viscosity [η] Measured in tetralin according to ASTM D 1601,
Expressed in dl / g.

(3) For isotactic index (II), a sample film is cut into a size of about 1 cm square, put in a Soxhlet extractor and extracted with boiling methyl alcohol for 6 hours.

The extracted sample is vacuum dried at 60 ° C. for 6 hours.

A sample weighing W (mg) is taken from this, which is again placed in a Soxhlet extractor and extracted with boiling n-heptane for 6 hours. Next, this sample is taken out, thoroughly washed with acetone, vacuum dried at 60 ° C. for 6 hours, and then weighed.

If the weight is W '(mg), the isotactic index is calculated by the following equation.

Isotactic index (%) = 100 × W '/ W (4) Glass transition temperature (Tg) 10 mg of sample was used as a scanning calorimeter DSC-II type (Perkin Elm
er) and start a temperature rise rate of 40 ° C / min from -20 ° C under a nitrogen stream to write a thermograph, and calculate the temperature at which the endothermic peak deviates from the baseline and the returning temperature. The temperature obtained by taking the average value is defined as Tg.

Of course, even if the sample is a composite film, it may be measured by this method.

(5) Surface roughness Rmax Expressed as the maximum roughness Rmax obtained at a cutoff of 0.25 mm according to JIS B0601-1976.

(6) Bromine number Measured according to JIS K -2543 -1979.

It means the number of g of bromine added to unsaturated components in 100 g of sample oil.

(7) Refractive index The refractive index N is determined by using an Abbe refractometer, Na-D ray as a light source, and methyl salicylate as a mint liquid to change the direction of the polarizing plate of the eyepiece lens to obtain the total refractive index in a specific direction. It is measured by the reflection method.

(8) Al was deposited on the adhesive film to a thickness of 600 Å with a bell jar type high vacuum vapor deposition device at a vacuum degree of approximately 1 × 10 ^-5 mmHg, and then the cellophane adhesive tape (made by Nichiban) was deposited on this vapor deposition surface. Adhere "cellophane tape"), rapidly peel off the cellophane tape, and evaluate the peeled state of the Al vapor deposition film.

○: Peeling area of Al vapor deposition film is 90% or more △: 〃 50 to less than 90% ×: 〃 less than 50% (9) Matting property ○, 50 when surface gloss (ASTM D2457) is 30% or less
% Or more is x, and the middle is Δ.

(10) Blocking property The measuring films are stacked on top of each other, a load of 2 kg is placed on a 3 cm square, and after standing at 40 ° C. and 65 RH% for 24 hours, the measuring film surface has a peeling force of 0. A sample with a weight of 400 g or more is marked with X, and an intermediate product is marked with Δ.

〔Example〕

 Next, examples of the present invention will be described.

Example As polypropylene, Mitsui Toatsu Co., Ltd., Mitsui "Noprene" JS1429 (measured intrinsic viscosity in tetralin [η]
= 2.25dl / g, isotactic index II = 98%)
As a specific hydrogenated petroleum resin, Esso Chemical Co., Ltd.
"ESCOLETS" 5320 containing nonpolar polydicyclopentadiene as a main component was used.

25 parts by weight of "ESCOLETS" 5320 was uniformly blended with 100 parts by weight of this polypropylene resin to obtain a raw material (I).

On the other hand, ethylene component 30% by weight, propylene component 70% by weight
Raw material of ethylene-propylene block copolymer (II)
And feed them to different extruders, melt at 220 ℃,
Melt coextrusion into two layers consisting of (I) / (II) at 85 ° C
A two-layer laminated unstretched film was obtained by casting on a casting drum kept at.

This film was immediately introduced into a hot-air oven-heated longitudinal stretching roll maintained at 135 ° C, and stretched 7 times in the longitudinal direction, and then transversely without a tenter heated at 158 ° C.
The film was stretched 10 times and heat-treated at 161 ° C. for 10 seconds while allowing 5% relax in the transverse direction to obtain a two-layer laminated film.

The surface of the film (II) of this film was subjected to corona discharge treatment in an atmosphere of air / carbon dioxide gas = 90/10 volume ratio, the thickness of the film (I) was 20 μm, and the thickness of the film (II) was 2 μm. A laminated film having a surface roughness Rmax of 0.6 μm was obtained.

The Tg of the film (I) was 32 ° C.

Then, Al was vapor-deposited on the film (II) layer to a thickness of 600 Å, and the moisture-proof film thus obtained was evaluated for properties such as water vapor transmission rate and Al layer adhesiveness.

The results are shown in the table below.

[Comparative example]

Instead of the film (II) layer used in the example, an Al vapor-deposited film was prepared in the same manner as in the example except that a film (II) layer made of an ethylene-propylene random copolymer containing 4% by weight of an ethylene component was used. Got

The characteristics of this film are also shown in the table below.

As is clear from this table, the moisture-proof film of the present invention,
Not only moisture-proof but also excellent in Al layer adhesion, blocking and matting.

Claims (1)

[Claims] 1. 100 parts by weight of polypropylene contains 5 to 100 of at least one resin selected from petroleum resins substantially free of polar groups and terpene resins substantially free of polar groups.
On at least one side of the film (I) mixed by weight,
The surface roughness Rmax is 0.15 ~ 20μm ethylene component 20
In the laminated film, a film (II) layer containing an ethylene-propylene block copolymer as a main component containing 40 to 40% by weight is laminated, and a metal vapor deposition layer is further formed on the film (II) layer. A matte moisture-proof film, wherein the glass transition temperature of the film (I) is 10 to 50 ° C.