JPS60184840A - 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 matte laminate film, and particularly to a laminate film that has high adhesive strength with metal vapor deposited layers and paper.
be.

[Prior art]

Conventional laminated films include ethylene, propylene,
Films laminated with block copolymers (for example,
7-. 32954) and a film in which a blend of polypropylene and high-density polyethylene or low-density polyethylene is laminated is known.

However, such conventional laminated films either have insufficient matte properties or require a thick matte layer to obtain sufficient matte properties, resulting in a decrease in total light transmittance. There was a drawback. Also, the top of the melting peak is 1
The temperature is lower than 20° C., and it also has the disadvantage that its matte properties disappear when pressed or heated during lamination processing with paper such as print laminate.

On the other hand, cigarette wrappers that require gas barrier properties, and gift boxes for Western alcoholic beverages that are matte and give a luxurious feel, have traditionally had drawbacks such as the soaring price of aluminum foil and the tendency to wrinkle when handled. For this reason, the use of laminated paper, which is a combination of metal-deposited film and paper, has been considered.

However, such laminated paper does not have sufficient adhesive strength between the film and the metal-deposited layer or the printed layer, so the bond strength is 19! It had drawbacks such as being easily damaged and peeling off due to rubbing.

[Purpose of the invention]

An object of the present invention is to provide a laminated film that has excellent matting properties, light transmittance, and resistance to matting due to heat and pressure processing (referring to the property that matting properties do not disappear).

Another object of the present invention is to provide a laminated film that has excellent adhesion to a metal vapor-deposited layer or paper when metal vapor deposition is performed or when bonded to paper such as print laminate.

[Structure of the invention]

In order to achieve the above object, the laminated film of the present invention has the following configuration, namely, a biaxially oriented polypropylene film (
On at least one side of A), the ethylene component is 10 to 50% by weight, and the other side is mainly composed of propylene, with 120 to 165% by weight.
The olefin polymer film (B) having three or more peaks of melting peaks between 0°C and 3°C is laminated, and the surface roughness Ra of the olefin polymer film (B) layer is set to 0°2 to 1.5μ. It is characterized by having a gloss level of more than 20 and less than 70.

The biaxially oriented polypropylene (hereinafter abbreviated as OPP) film (A) in the present invention is a biaxially oriented film that has been stretched by a well-known stretching method such as simultaneous biaxially or sequentially biaxially, and is 50% by weight of the film. The above is a film made of polypropylene.

The polypropylene is preferably a commonly used polypropylene homopolymer, and in some cases less than 50% by weight of other olefins such as ethylene,
Homopolymers and copolymers of α-olefins represented by butene-1 can be used.

The thickness of the OPP film is not particularly limited, but is preferably 3 to 120 microns.

Additives of the types known to be normally added to OPP films (thermal stabilizers, antioxidants, nucleating agents, antistatic agents, lubricants, fillers, weathering agents, etc.) are added to the OPP film according to the characteristics of the present invention. It may be added as long as it does not impair it.

The polymer film (B) in the present invention is a polymer whose ethylene component is 10 to 50% by weight, preferably 15 to 40% by weight, and the other main components are propylene, and the main component is propylene.
A polymer having three or more melting peaks in the range of 0 to 165°C is used. Specifically, ethylene propylene block copolymer (hereinafter referred to as EPB) having the above characteristics is used.
(abbreviated as G). Alternatively, it refers to a film made of a blend of EPBG and polyethylene, polypropylene, other α-olefins, ethylene propylene random copolymer (hereinafter abbreviated as EPRC), etc. In addition, when blending polypropylene, it is preferable that the amount of blending be less than 50% by weight based on the polymer film (B) so as not to reduce the adhesive strength.

In addition, the polymer fill 4 (B) has a melting peak of 1
3 or more points in the range of 20 to 165°C, preferably 120 to
3 points or more and 8 points or less in the range of 165°C, more preferably at least 1 point or more in each of the following three ranges: 120°C or more and less than 130°C, 130°C or more and less than 150°C, and 150°C or more and 165°C or less, Moreover, the surface on the side opposite to the side laminated to the OPP film (A) has a surface roughness Ra of 0.2 to 1.5 μm, preferably 0.2 to 1.5 μm.
Must be 0μ.

Note that the temperature difference between the peaks of the melting peaks is preferably 5° C. or more.

If the ethylene component in the polymer film (B) is less than 10% by weight, strong adhesive strength at the above-mentioned specific roughness cannot be obtained and printability is also poor.

If the ethylene component exceeds 50% by weight, the retention of the above-mentioned specific phase will be reduced, and a uniform composite will not be formed during composite by coextrusion, resulting in so-called lamination failure.

If the surface roughness Ra is outside the range of 0°2 to 1.5 μm or the number of melting peak vertices is less than 3, sufficient matting properties cannot be obtained.

Note that if there are three or more melting peaks between 120 and 165°C and no peaks below 120°C, the unevenness on the film surface will not be easily crushed by heating or pressure during metal deposition or lamination. , is preferable because the matte property is stabilized.

Therefore, when blending polyethylene, high density polyethylene is preferred. Also, among the peaks of three or more melting peaks, the peak of the maximum peak is 130'C or higher J: 15
If it is below 0°C, it will have fine irregularities and will have particularly excellent matte properties.

The rough surface of such a polymer film (B) contains an ethylene component,
Molding is carried out by using polymers in which the number of apexes of melting peaks is within the above-mentioned specific range, but if necessary, well-known methods such as embossing and methods for developing spherulites may be used in combination. Here, the surface roughness Ra refers to the center line average roughness (cutoff value 0.25nun), and is based on J15-B-0601. Also,
If the number of melting peak vertices is 3 or more, the polymer can be made by polymerizing EPBC or by blending polyethylene with EPBC so that the required number of melting peak vertices are formed in a specific temperature range.
4.

Further, the surface gloss of the polymer layer when formed into a laminated film is greater than 20 and less than 70, preferably less than 50. When the surface glossiness is less than 20, the gloss on the surface of the deposited layer disappears so much that it becomes lead-colored or whitish and loses its sense of luxury.

Moreover, if the surface glossiness exceeds 70, the diffused reflection will be low and the matting properties will be poor.

Here, the thickness of the polymer film (B) is not particularly limited, but is preferably 0.5 to 10 μm.

The polymer film (B) contains additives known to be commonly added (thermal stabilizers, antioxidants, nucleating agents, antistatic agents, lubricants, fillers, weathering agents, etc.). may be added within a range that does not impair the characteristics of the present invention. Moreover, it is preferable that the polymer film (B) is biaxially stretched.

In the polymer film (B), polyethylene and EPB
When a blend of C is used, the ethylene component refers to the total ethylene component including the ethylene components of polyethylene and EPBG.

The ethylene content of the polymer film (B) can usually be determined by using an infrared absorption spectrum at 1170 cm-' or 720 cm-' (1) absorbance a ratio and V) analytical line method. 720 cm-' for EPRC
Since the absorption of When the ethylene content is small, a complete absorption spectrum may not be exhibited and absorption may occur in the form of scraps, but even in this case it can be considered that there is absorption.

In addition, the lamination method of the laminated film is for each film (A),
(B) can also be bonded using an adhesive, but each film (A>
A co-extrusion method in which the individual die pieces are combined immediately before extrusion, a method in which they are individually melt-extruded and then stacked and bonded together before being cooled and solidified, or Advantageous methods include melt extrusion of the polymer film (B) and adhesion.

In addition, the surface of the laminated film of the present invention is preferably activated by surface treatment such as corona discharge treatment, oxygen treatment, flame treatment, etc. At that time, it is preferable to activate it in nitrogen gas or nitrogen and carbon dioxide mixed gas. Corona discharge treatment is preferred.

The laminated film of the present invention is often used as it is, or after being vapor-deposited on the surface of the polymer film (B) layer, it is bonded to paper.

For lamination of the vapor-deposited film and paper, adhesives normally used for bonding aluminum foil and paper, such as vinyl acetate, acrylic, urethane, wax, rubber, and latex, can be used. The lamination method is wet,
Either the dry method or the heat-melt method is acceptable, but the wet method, which uses a water-based emulsion type binder, is the cheapest. The above adhesive is OPP surface, that is, film (A)
Although its adhesive strength to the layer is weak, in the present invention, the film (B) is made of a specific ethylene component, so even if the laminated surface (bonding surface) of the film is a vapor-deposited surface, it can be bonded to a non-vapor-deposited surface. sufficient bonding strength can be obtained.

That is, on the non-evaporated surface, the polymer film (B) is present and has very good adhesion to the paper, and does not peel off during this period. In addition, when applying adhesive to the vapor-deposited surface and pasting it with paper, conventional films did not have sufficient adhesion between the vapor-deposited layer and the film layer, resulting in peeling between them. It has the great advantage of eliminating drawbacks.

Therefore, since the laminated film of the present invention has the above-mentioned advantages, it can be used for print lamination to be attached to printed matter, for release sheets during plywood production, for drafting, for printing, for free albums, for labels, and for packaging. It is also used as a dielectric material for capacitors, for decorative or adhesive tape applications, and for impregnation with insulating oil.

It is also preferably used for vapor deposition as a film with a soft luster. The film deposited on the polymer film (B) layer has extremely strong adhesive strength and is particularly suitable for vapor deposition applications.

In addition, in the case of laminated paper laminated with paper, it is useful as gift boxes for Western liquors, labels, and packaging paper.

Next, an example of the method for manufacturing the laminated film and laminated paper of the present invention will be described.

Polypropylene (raw material for OPP film (A>)), a polymer having a predetermined melting peak and containing a specific ethylene component [raw material for film (B)], and the OPP film as a layer on one side or in the center. Specifically, the two-layer or three-layer structure is (A)/(B) two layers, (B)/(A)
/ (B) as three layers at the same time in a sheet form with 250 to 30
After melt extruding at 0°C, the sheet is cooled and solidified by contacting it with a cooling surface at 20 to 95°C in a short time, usually within 1 to 50 seconds, to below IOO'C, and then the sheet is extruded at 110 to 150°C.
After being stretched 3 to 7 times in the longitudinal direction while heating to A stretched laminated film is obtained.

Lamination of the polymer film (B) layer is not limited to the above-mentioned coextrusion, and may be performed before -axial stretching, or before or after biaxial stretching.

Further, depending on the case, a simultaneous biaxial stretching method may be employed. (B) In order to roughen the surface, after laminating, the stretching temperature in at least one of the stretching steps is set to 130 to 1
This can be achieved by setting the temperature to 65°C.

〔Effect of the invention〕

The present invention uses an olefinic polymer film (B) whose melting peak as measured by a differential scanning calorimeter (DSC) is 120 to 165 T as a layer to which a matte property is attached. Axial oriented polypropylene film (A)
By laminating the two layers, we were able to obtain the following excellent effects.

(a) By setting the melting peak to three or more points, surface scattering increases, resulting in an unprecedented film with low gloss and high total light transmittance.

(b) Furthermore, since the top of the melting peak was set at 120° C. or higher, it was possible to eliminate the drawback that the matte property disappears under normal heating and pressurizing conditions during print lamination processing, which is applied to printed matter, for example.

(c) The adhesive strength between the surface (B) and the deposited film is strong, and the abrasion resistance and abrasion resistance are excellent. Therefore, even if the vapor-deposited surface is exposed, it can be used satisfactorily.

(d) The bonding strength between the (E3) side of the film and paper or printed matter is extremely strong, and the film has excellent matte properties, so it is suitable for print lamination.

(e) Wet bonding using an inexpensive water-based emulsion type adhesive is possible for bonding with paper.

(f) The surface of the film (B) has excellent printability.

[Method of measuring characteristics, evaluation criteria]

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

(1) Vertex of melting peak Perkin-E 1mer differential scanning calorimeter M
Using the odelDSG-2 model, 5 samples were heated to 280°C at a heating rate of 20°C/min, held for 5 minutes, cooled at the same rate, and heated again, so-called second run. Take the melting curve. The apex of the melting peak refers to the inflection point or shoulder-like point of this curve.

(2) Vapor-deposited film adhesion strength A commercially available cellophane adhesive tape (manufactured by Chiban Co., Ltd.) is attached to the vapor-deposited surface and peeled off at an angle of 180°. Based on the adhesion area of the vapor-deposited metal, the 6 levels (index ) was evaluated.

(3) Glossiness J l5-Z-8741 Method 2 < GS (60'
), and the lower this value is, the better the matting effect is, and the higher this value is, the better the glossiness is.

Table 1 (4) Bonding strength Adhesive “Lifebond AV-650TL” on the film surface
(Manufactured by Nichibei Kako Co., Ltd., apply 8g of water-based emulsion tie whose main component is vinyl acetate-acrylic copolymer, paste white cardboard (350p/m2),
After drying at 00"O for 30 seconds to obtain a laminate, the film portion of the film laminate is peeled off and the state of peeling is observed. If the laminate strength is strong, the entire paper layer will be destroyed.

(5) Printability The film surface was printed with polypropylene ink "PP5T" (manufactured by Toyo Ink Co., Ltd.), and the printing ink adhesion strength was determined using the same evaluation method as in the above (2) Vapor-deposited film adhesion strength.

(6) Disappearance resistance 1 kg/ci between aluminum plates heated to 115℃
The glossiness of the surface of the specific polymer layer of the film heat-pressed for 0.5 seconds was measured and expressed as the difference from the glossiness before hot-pressing. The larger the difference in glossiness, the worse the erasure resistance.

〔Example〕

Hereinafter, one embodiment of the present invention will be described based on Examples.

(Example 1) Ml (melt index) at 230°C = 2g/l 0
Polypropylene extruder (1), ethylene component 22
EPBC was polymerized with a propylene component of 78% by weight and the apex of the DSC melting peak was at three points of 123°C, 147°C, and 157°C, and was fed to Extrusion II (II) using a three-layer die. The polypropylene was melt-coextruded at 270° C. so that EPBC was laminated on both sides, and wound around a cooling drum at 30° C. to obtain an unstretched sheet of about 340 μm (base polypropylene: about 240 μm). This sheet is 1
It was stretched 4.5 times in the longitudinal direction while heating at 20°C, and then introduced into a tenter at 170°C and stretched 9 times in the transverse direction to give a relaxation rate of 7%. ) was obtained.

Both sides of the film were then subjected to corona discharge treatment with an electrical energy amount of 15 W·min/m 2 . These films were set in a vacuum evaporation device, and the aluminum evaporation film was 60%
It was deposited on one side to a thickness of 0 angstroms.

As a comparative example, the polymer fed to the extruder (II) was changed as follows, and the other conditions were exactly the same as in Example 1.

(Comparative Example 1) EPBC with DSC melting peaks at two points, 128°C and 160°C, and an ethylene component of 22% by weight and a propylene component of 78% by weight.

(Comparative Example 2) EPBC containing 5% by weight of ethylene (melt index 3(]/10 minutes, peak of DSC melting peak at 125°C)
, 143°C, 160°C) (Comparative Example 3) A raw material obtained by blending the EPBG of Comparative Example 1 with 15% of low density polyethylene.

These results are summarized in Table 2. As is clear from Table 2, the laminated film of the polymer layer having the melting peak characteristics shown in Example 1 had a low degree of gloss due to the diffused reflection on the surface, resulting in a film with excellent matte properties.

In addition, since the top of the melting peak is on the high temperature side, it has excellent extinction resistance and maintains matte properties, and is found to be excellent in lamination applications (print laminates) where heat and pressure are applied.

Further, when the film was made into a vapor-deposited film, it had a matte metallic luster and the adhesion strength of the vapor-deposited film was strong.

Furthermore, it has excellent printability and strong lamination strength with paper, making it the ideal film for film-laminated paper. DS
C with two melting peaks has poor matting properties (
Comparative Example 1), those containing less than 10% by weight of ethylene had weak vapor deposited film adhesion strength and bonding strength, and poor printability (Comparative Example 2). The top of the melting peak of DSG is 1
Those at temperatures below 20°C were particularly poor in extinction resistance (Comparative Example 3).

Claims (1)

[Claims] (1) At least one side of the biaxially oriented polypropylene film (A> has an ethylene component of 10 to 50% by weight, the other main component is propylene, and has three or more melting peak vertices between 120 and 165°C) The olefin polymer film (B) is laminated, and the olefin polymer film (B) layer has a surface roughness Ra of 0.2 to 1.5 μ and a surface gloss of more than 20 and 70 or less. A laminated film featuring: