JPS588645A - Polypropylene composite film printed - 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 object of the present invention is to provide a polypropylene composite film, particularly a film that has excellent printing ink adhesion, metal thin film adhesion, heat sealability, and transparency, and is rich in processability. . Recently, hygiene in food packaging, textile packaging, etc.
There are requests for improvements in odor, etc., and improvements in processing, such as faster printing, reduction of residual solvent, use of low-cost ink, and expansion of the operational range of bag-making processing conditions (easier processing). It's getting even higher. In response to this demand, an ink containing cellulose derivatives as a binder (product name:
However, currently commercially available polypropylene film printing inks use specialized inks, and storage and management of the ink, as well as anchor coating agents (
It has the disadvantage of having to have a variety of inks and adhesives during processing, such as changing (for later laminating with a low melting point film such as polyethylene), storage, etc. Furthermore, since the processed surface has no heat-sealability at all, it is generally coated or laminated with a heat-sealable material. In addition, recently, as an attempt to solve this situation, films with a low-temperature sealable polymer laminated on one side have become commercially available, but these still have to be selected from inks for polypropylene films. do not have. In order to provide printability, attempts have also been made to coat the film surface with a resin solution that promotes adhesion. However, this method is complicated, expensive and wasteful.

The present inventors have arrived at the present invention in order to solve these problems. That is, in the present invention, at least one side of a propylene polymer film layer (sometimes abbreviated as layer A) containing 80% by weight or more of propylene constituents has ethylene and/or 99 to 50% by weight of propylene and a carbon number of 4 or more. α−
A polypropylene composite film coated with a layer (sometimes abbreviated as layer B) containing an α-olefin copolymer containing 71 to 50% by weight of olefin and at least uniaxially stretched, - The surface of the layer containing the olefin copolymer is processed to have a surface wetting tension of more than 35 dynes/hundred, and at least a portion of the processed surface contains an ink containing a cellulose derivative as a binder. This is a printed polypropylene composite film characterized by having a printed layer formed thereon.

More specifically, in the present invention, the polymer forming layer A is polypropylene, a copolymer such as a propylene/ethylene copolymer, or a polymer other than polypropylene and polypropylene, preferably a polyolefin polymer (for example, polyethylene, ethylene/ethylene copolymer, etc.). It is a mixture of propylene copolymer, polybutene-1, poly-4-methylpentene-1, etc. In any case, layer A must be made of only polypropylene, or have a composition in which the propylene component accounts for 80% by weight or more of the total amount (hereinafter, ``H'' indicates weight% unless otherwise specified) as a copolymer component or a polymer mixture component. be.

On the other hand, layer B, which is a layer containing an α-olefin copolymer, is composed only of the α-olefin copolymer, or is a polymer mixture of the copolymer and another polymer. In the present invention, the α-olefin copolymer refers to a copolymer containing 99 to 50% by weight of ethylene or/and propylene and 1 to 50% by weight of an α-olefin having 4 or more carbon atoms. It is a copolymer of ethylene and/or an α-olefin having 4 or more carbon atoms such as propylene phthene-1 and hexene-1,4-methylpentene-1.

For example, ethylene-butene-1 copolymer, ethylene-hexene-1 copolymer, ethylene-4-methylpentene-1
Examples include copolymers, propylene-butene-1 copolymers, propylene-4-methylpentene-1 copolymers, and the like. In this copolymer, α-
The copolymerization ratio of olefin is 1 to 50% by weight, preferably 2 to 8% by weight, particularly preferably 2 to 3% by weight.
Weight%. When layer B is formed by mixing an α-olefin polymer and another polymer, the other polymer is preferably a polyolefin, such as polyethylene,
Polypropylene, Bo IJ 7” Ten-1, Poly-4-
Examples include homopolymers such as methylpentene-1 and copolymers with other copolymerizable monomers. The mixing ratio is 100 to 20 inches for the α-olefin copolymer and 0 to 80 inches for the other polymers. A preferred mixing ratio is 100 to 40% of the former.

This is because if the proportion of the α-olefin copolymer is less than 20%, the adhesiveness of the printing ink and the adhesiveness of the metal thin film will decrease. Regarding the characteristics of the B layer containing the α-olefin copolymer of the present invention, in particular, the ethylene-α-olefin copolymer has excellent adhesion to printing inks containing cellulose derivatives or to metal thin films. show.

However, it has a rather negative tendency when it comes to transparency.

On the other hand, it has been experimentally confirmed that when layer B contains a globylene-α-olefin copolymer, the adhesiveness is inferior to the former, but the transparency is extremely good.

The composite film consisting of layer A and layer B of the present invention can be obtained by coextrusion, melt extrusion lamination, heating stretching with a roll stretching machine and adhering simultaneously, or longitudinally stretching one and then composite adhering the other. Furthermore, methods such as longitudinal stretching, adhesion, and subsequent stretching in a direction perpendicular to the above-mentioned direction can be employed. Of course, these combinations may be used as appropriate, or applied means other than those described above may be used. When biaxially stretching, there is no particular restriction, and in order to carry out sequential biaxial stretching, the unprocessed film is usually first stretched vertically in the longitudinal direction of the film using a roll stretching machine, and then stretched perpendicularly to the longitudinal direction of the film using a tenter. Although a method of transverse stretching is used, transverse stretching and subsequent stretching may be performed in the reverse order. In the case of simultaneous biaxial stretching, either the tenter method or the inflation method can be used. In either method, the unstretched film of the present invention can be stretched using the stretching ratio, stretching temperature, and stretching speed that are possible for ordinary polypropylene films. In any case, at least uniaxial stretching is necessary to achieve the object of the present invention. Is the entire two layers uniaxially stretched?
Or when layer B is uniaxially stretched and layer A is biaxially stretched,
Furthermore, there are cases where the A layer is biaxially stretched and the B layer is not stretched, but the preferred film of the present invention is one in which at least both layers are at least uniaxially stretched. Specifically, biaxial stretching is abbreviated as (BO), and uniaxial stretching is abbreviated as (UO), resulting in UO-A layer/UO-B layer, BO-
A layer/UO-B layer, BO-A layer/BO-B layer 1. UO
-A layer/BO-B layer etc. are preferred examples. Comprehensively considering mechanical properties, transparency, gloss, and mechanical suitability, the most preferable is the BO-A layer/U O-B layer or the BO-A layer/
This is the BO-B layer. Of course, an unoriented layer obtained by relaxing the orientation of the stretched layer by heat treatment is treated as an oriented film. The film thus obtained was subjected to surface activation treatment by a conventional method, and the surface wetting tension was 35 d.
Those exceeding yne/cy* are preferred.

The structure of the film of the present invention is as described above, but preferably three or more layers are better than two layers. This is because, in the case of two layers, when heated υ and tension are applied, there may be a problem of bending. The thickness of the B layer forming the surface layer is 0.1 to 1 for normal use after the stretching is completed.
0 micron, preferably 0.4 micron to 5 micron is chosen. If it exceeds 10 microns, the transparency will be poor, which is not preferable for applications requiring transparency. However, if transparency is not required at all, this limitation is not necessary. On the other hand, a thickness of 0.1 micron or more is necessary from the viewpoint of adhesion.

As mentioned at the outset, the film used in the present invention is characterized by its adhesion to ink for cellulose derivative films (for example, Cellophane (trade name)).

On the B side of the polypropylene composite film layer consisting of at least two layers detailed above, (B) / (A) /
In the combination film of 03), one B layer surface or both B layer surfaces
The gist of the present invention is to print on the layer surface, and furthermore, in the case of the antistatic formulation of (5)/(A), to print on the B layer surface. Of course, even if an antistatic agent is added to layer B, the effects of the present invention can be observed, but the originally excellent adhesiveness may tend to be impaired. Of course, three or more layers can also be applied in accordance with the above purpose.

B layer surface (if both surfaces, at least a part of it can be printed using an ink containing the following cellulose derivative as a binder).

Cellulose derivatives include nitrified cotton and trocellulose)
is preferred, but other examples include cellulose ethers such as methylcellulose, ethylcellulose, and hydroxyethylcellulose, and cellulose esters such as cellulose propionate. In addition to these cellulose derivatives, there are polyamide resins made of condensates of polymerized fatty acids and polyamines, rubber derivatives such as cyclized rubbers and chlorinated rubbers, ester rubbers such as rosin and glycerin esters, and amine resins such as urea and melamine resins. However, the present invention is not limited thereto. For example, when nitrified cotton is contained as a binder, the degree of nitrification is usually 9 to 12.5q6, and the degree of polymerization is 20 to 10 seconds, as determined by the Vercules method, which exhibits the characteristics of nitrocellulose. Inorganic or organic pigments and dyes are further used in the mixture containing the above-mentioned cellulose derivatives, such as titanium white, yellow lead, copper powder, phthalocyanine blue, etc., which are appropriately used depending on the color. These mixtures are diluted with alcohols, esters, ketones, and various organic solvents such as ethyl acetate, benzene, toluene, and xylene to adjust the viscosity before use. Further, volatile fest etc. can also be used as a coloring agent. Such printing ink is overprinted once or several times over a part or the entire surface of the B layer. These printing ink layers adhere extremely well to the film and can be easily peeled off by rubbing, scratching, adhesive tape, etc. Therefore, even if other polymers or film-like materials are laminated, the interface between the ink and the film is practically sufficient. It has strength. Practical strength means, for example, weight for packaging materials,
45 f/15, although it varies depending on shape, properties, etc.
This means 100 f/15 m or more, preferably 100 f/15 m or more. The film used in the present invention exhibits extremely good adhesion to printing inks containing sicellose derivatives by corona discharge treatment, which is not the case with conventional polypropylene films.

Further, the present invention will not be adversely affected even if antistatic agents, lubricants, anti-blocking agents, dyes, pigments, weathering agents, ultraviolet inhibitors, various stabilizers, etc. are mixed into the film of the present invention. However, the effect of the present invention can be significantly exhibited by not including an antistatic agent in the B layer. In addition to being used as a packaging material, this film can also be used as a metal mounting tape and as an adhesive. The method for measuring characteristic values in the present invention is as follows.

(1) Transparency Measured according to JIS-6714 method.

(2) Adhesiveness of ink (adhesion between layer B and printing ink layer) (a) Tape release Using a commercially available adhesive tape (product name: cellophane tape), attach it to the printing ink layer surface without creating air bubbles, and quickly peel it off. The peeling condition at the time of peeling was classified and evaluated as follows.

◎No peeling at all. Good.

○ hardly peels off. Good (peeling area approximately 10% or less) △10% or more to 50 pieces peeled off. Ya\Bad.

*50- or more peels off almost completely.

Bad.

(b) Rub The film was placed between two fingers with the ink side facing inside, and rubbed 5 to 6 times to check the degree of peeling.

Evaluation is same as above.

(c) Scratching Place the printing ink layer on top of cardboard with a thickness of IX, scratch it with your fingernail, and check the extent to which the printing ink layer has fallen off. The evaluation is as follows.

◎Does not fall off at all. Good.

○ hardly falls off. Good.

△It falls off a little. Slightly poor.

×Easily falls off.

(3) Heat-sealability After the film was heat-sealed for 150°" h/ads l s6c and left in an ambient atmosphere at 20°C and 165% RH for 24 hours, it was heated with 200 U/1 TIIn in the longitudinal direction using Tensilon manufactured by Toyo Seiki Co., Ltd. The heat seal strength was defined as the force required to peel off the film at a speed.

The peeling angle is 180 degrees.

Example 1 Intrinsic viscosity 2. The fA layer is made of tactical polypropylene (isotactic index 92%) with Odt/f (viscosity by 135°C tetralin solution), and this layer is configured as the center layer, and propylene-butene-1 copolymer is coated on both sides. The combined product (butene-1 copolymerization ratio: 20% by weight) was laminated as layer B. #A layer polymer and B layer polymer are introduced into a die from separate melt extruders in a molten state,
This is spread into a flat plate inside the die and combined into a flat plate B/
A three-layer A/B integrated unoriented film was molded.

The film was then stretched 4 times in the machine direction at 135° C., and then 8.0 times in the cross direction. After biaxial stretching, it was heat treated at 150°C for 10 seconds. The resulting biaxially stretched film had a total thickness of about 22 microns, with the B layer being 2 microns and the A layer being 18 microns, and was further subjected to a corona discharge treatment so that the surface wetting tension was 50 dynes/F. This film was printed with the following printing inks. An ink containing nitrified cotton as a main binder and having a viscosity of H seconds and a degree of nitrification of 11.0% was applied to the corona discharge treated surface of layer B by the Vercules method.

(Printing ink) A) Binder Nitrocellulose 70% Polyamide resin 30% Solvent Methanol 2% Ethanol 43% Neopentyl alcohol 24% Inglobil alcohol Isopropyl 2thiacetate 15% Normal propyl acetate 14% Solvent ←) A 25% solution of binder (A) was prepared, and 5% (by weight) of titanium white was mixed therewith.

Comparative Example 1 Using the tactical polypropylene of Example 1, it was similarly biaxially stretched and treated to have the same surface wetting tension. The thickness is 22 microns.

This was printed with the above ink.

Comparative Example 2 A film formed only from an ethylene propylene copolymer with an ethylene content of 3% by weight, biaxially stretched, and subjected to corona discharge treatment to a surface wetting tension of 50 dynes/crn, but with poor printability, poor transparency, and weak stiffness. Therefore, it was not possible to obtain a film with good processability as in the present invention.

Comparative Example 3 Low density polyethylene (density 0.92
(1/crI), and the film was similarly formed and evaluated.

Example 1 Comparative Example 1 Comparative Example 2 Comparative Example 3 Average thickness 22.0μ22.0μ22.0μ22.0
μ Transparency 92cm 95% 85
% 8o ink adhesiveness (tape) ○ ×
×× (kneading) ○ ××× (scratching) ○ △ △ △ Heat sealability 380i5. 0 215 39
5 Patent Applicant Toyobo Co., Ltd. 17- Procedural Amendment January 29, 1981 Commissioner of the Patent Office Shima 1) Haruki Tono (IL)
Display of the case Patent application No. 1980 Kisara No. Application filed on January 25, 1988 2 Polypropylene composite film with the name of the invention printed 8, Amendment +
Relationship to the case of the person who filed the patent application: 2-2-8-4 Dojimahama, Kita-ku, Osaka City The subject of the amendment is corrected to ``Penten''.

(2) On page 17, line 5 of the same text, correct the word ``open j'' to ``use''. Written amendment to the above procedure c
Method) 1 Indication of the case Patent Application No. 10386a of 1988 Name of the invention Printed polypropylene composite film & Person making the amendment Relationship to the case Patent applicant No. 2-2-8 Dojimahama, Kita-ku, Osaka 1- Akira Details & Contents of Amendment (1) The first page of the specification is corrected as shown in the attached sheet.

2-2. Claims At least one side of a propylene-based polymer film layer containing 80% by weight or more of propylene constituents contains ethylene or/and 99-50% by weight of propylene and 1-50% by weight of α-olefin having 4 or more carbon atoms. % and is at least uniaxially stretched, the surface of the layer containing the α-olefin copolymer has a surface wetting tension of is applied to a value exceeding 35 dynes/an, and at least a portion of the processed surface is coated with a printed layer of ink containing a cellulose derivative as a binder. printed polypropylene composite film.

3. Detailed description of the invention

Claims (1)

[Claims] At least one side of a propylene-based polymer film layer containing 80% by weight or more of a propylene constituent component is ethylene or/and an α-olefin containing 99 to 50% by weight of propylene and 1 to 50% by weight of an α-olefin having 4 or more carbon atoms. A polypropylene composite film coated with a layer containing an α-olefin copolymer and uniaxially stretched at least a little, and the surface of the layer containing the α-olefin copolymer has a surface wetting tension of 35 dynes/crn. What is claimed is: 1. A printed polypropylene composite film which has been processed to a higher value, and at least a portion of the processed surface is provided with a printed layer formed of an ink containing a cellulose derivative as a binder.