JPH04189138A - Laminated film of polyolefine resin - Google Patents

Abstract

PURPOSE:To improve a printing property and adhesion by laminating a surface resin film layer of random copolymer consisting of alpha-olefine and a non-conjugate diene group on a base material film layer consisting of polypropylene resin. CONSTITUTION:At least, on one surface of a base material film layer consisting of polyolefine resin, a surface resin film layer is laminated for obtaining a polyolefine resin laminated film, which is comprised of at least one kind of 3-12 carbon number of alpha-olefine, and at least one kind of random copolymer of a non-conjugate copolymer group denoted by a formula I (R<1> shows an alkyl group of 1-8 carbon number, R<2>, R<3>, R<4> and R<5> show hydrogen atoms or an alkyl group of 1-8 carbon number, and (n) shows the number of 2-10), or the random copolymer resin of the alpha-olefine, non-conjugate diene, and ethylene, wherein a non-conjugate diene group containing rate in the random copolymer resin is 0.1-15mol.%, and all ethylene containing rate is 0.1-4mol.%. Since the polyolefine resin laminated film is provided with a resin film containing a specific resin having a C=C combination of a side chain, a printing and coating property are given thereto.

Description

DETAILED DESCRIPTION OF THE INVENTION [Background of the Invention] <Industrial Field of Application> The present invention relates to a polyolefin resin laminated film that has excellent adhesion to general-purpose printing inks such as cellophane ink and water-based ink.

<Prior art> Films made of polyolefin resins such as polyethylene resins, polypropylene resins, and polybutene-1 resins have excellent moldability, transparency, chemical resistance, packaging properties, mechanical properties, etc. Therefore, it is widely used as a packaging material. Since such polyolefin resin films have the disadvantage of poor printing ink adhesion and adhesive adhesion, it is widely practiced to improve them by subjecting the film surface to corona discharge treatment. It is being said.

<Problems to be Solved by the Invention> However, simply subjecting the surface of such a polyolefin resin film to a corona discharge treatment does not achieve adhesive strength that fully satisfies market demands. In particular, when stronger adhesive strength is required or when using general-purpose printing inks such as cellophane ink or water-based ink, a thin film of polyethyleneimine, alkylene glycol monocarboxylic acid ester, etc. Attempts are being made to improve adhesion by forming the film on the surface of the resin film, but there are still practical issues with regard to printability and adhesion. As a result, the effect disappears or the duration of the effect is short, and the current situation is that the effect is not yet fully satisfied.

In particular, in the case of a two-wheel stretched polypropylene film, a layer consisting of a modified polypropylene film modified with an unsaturated carboxylic acid or its anhydride is laminated on the surface of the biaxially stretched polypropylene film, and this modified polypropylene layer is treated with a corona discharge treatment. It has been proposed to improve the adhesion by
8-17123, etc.), although this method has been put into practical use to some extent, it still has problems in terms of practical adhesion, as well as a decrease in transparency and the possibility that films may The current situation is whether this is causing problems such as blocking.

On the other hand, many methods have been introduced to improve adhesion by performing the corona discharge treatment in an inert gas atmosphere such as nitrogen scum, but these methods have not sufficiently solved the problem of poor adhesion. It's not something that exists.

[Summary of the invention]

Summary> In view of the above problems, the present inventors have conducted intensive research and have discovered that a resin film layer containing a random copolymer using a specific monomer is laminated on a polyolefin resin film. The present invention was completed based on the knowledge that a polyolefin resin laminated film having excellent adhesion to printing inks, particularly cellophane inks, water-based inks, and other general-purpose inks can be obtained.

That is, the polyolefin resin laminated film of the present invention has at least one α-olefin having 3 to 12 carbon atoms on at least one side of a base film layer made of a polyolefin resin, and at least one α-olefin having a general formula (wherein R is a carbon number 1-8 alkyl group, R2, R3, R4 and R5 are each independently a hydrogen atom or a C1-8 alkyl group, n is 2-10
A random copolymer resin of ethylene and at least one non-conjugated diene represented by 0.1~1
It is characterized by being laminated with surface resin film layers having an ethylene content of 5 mol% and an ethylene content of 0.1 to 4 mol%.

Effect〉 A surface resin film layer made of a random copolymer of an α-olefin having 3 to 12 carbon atoms, a non-conjugated diene with a specific structure, and ethylene is laminated on a base film layer made of a polyolefin resin. The polyolefin resin laminated film of the invention has a resin film layer on the surface containing a specific resin having a C-C bond in the side chain. By performing surface treatment, polar groups can be easily introduced onto the surface of the film, thereby providing excellent printability, paintability, etc. not found in conventional polyolefin resins. It is extremely useful industrially.

[Detailed description of the invention]

[I] Layer structure of laminated film The polyolefin resin laminated film of the present invention basically has a surface resin film layer containing the following random copolymer on at least one side of a base film layer made of the following polyolefin resin. It is made by laminating layers.

(]) Base film layer The polyolefin resin used as the base film layer of the polyolefin resin laminated film of the present invention includes ethylene resin (including resins from low density to high density), propylene resin, and butene resin. 1-based resins, 4-methylpentene-1-based resins, etc. Among these, it is particularly preferable to use ethylene-based resins and propylene-based resins. Specific examples of these resins include ethylene homopolymer (including low density to high density), ethylene/propylene random copolymer, ethylene/butene-1 random copolymer, ethylene/hexene-1 random copolymer. , ethylene/4-methylpentene-1 random copolymer, propylene homopolymer, propylene/ethylene random copolymer, propylene/butene-1 random copolymer, propylene/hexene-1 random copolymer, propylene/ Examples include a 4-methylpentene-1 random copolymer, and it is particularly preferred to use a polymer or copolymer.

(2) Surface resin film layer The resin used for the surface resin film layer laminated on the base film layer of the polyolefin resin laminated film of the present invention includes at least one α-olefin having 3 to 12 carbon atoms; , the general formula (wherein R1 is an alkyl group having 1 to 8 carbon atoms, preferably 1 to 4 carbon atoms, R2, R3, R4 and R5 are each independently a hydrogen atom or a hydrogen atom having 1 to 8 carbon atoms, preferably 1 to 4 carbon atoms) (n is a number of 2 to 10, preferably 2 to 5, respectively) and ethylene; polymerization,
It contains a random copolymer resin in which the content of non-conjugated diamines is 0.1 to 15 mol% and the ethylene content is 0.1 to 4 mol%.

(a) Constituent Components The random copolymer forming the surface resin film layer is obtained mainly by copolymerizing the following monomers.

α-olefin having 3 to 12 carbon atoms α-olefin having 3 to 12 carbon atoms constituting the above random copolymer
As the olefin, propylene, butene-1, pentene-1, hexene-1, octene-1,3-methylbutene-1,3-methylpentene-1,4-methylpentene-1,3,3-dimethylbutene-1 ,4,4-dimethylpentene-], ]3-methylhexene-14-methylhexene-1,4,4-dimethylhexene-1,5-methylhexene-1, allylcyclopentane, allylcyclohexane, styrene, allylbenzene, 3 -cyclohexylbutene-1, vinylcyclopropane, vinylcyclopentane, vinylcyclohexane, 2-vinylbicyclo[2,2,1)hbutane, and the like. Preferred among these α-olefins are propylene, butene-1, ]3-methylbutene-14-methylpentene-1, styrene, and the like, with propylene being particularly preferred. Two or more of these α-olefins may be used, and in that case, the amount should be at least 70% by weight, preferably 80% by weight, based on the total of either one of the main α-olefins or α-olefins.
It is desirable that the amount is at least 90% by weight, particularly preferably at least 90% by weight.

The non-conjugated diene also has the general formula (1) constituting the random copolymer.
) Examples of non-conjugated dienes are 1,
5-heptadiene, 5-methyl-1,5-hebutadiene, 6-methyl-1,5-heptadiene, 1,5-octadiene, 5-methyl-1,5-octadiene, 6-methyl-1,5-octadiene 1,5-dienes such as;
1,6-octadiene, 6-methyl-1,6-octadiene, 7-methyl-1,6-octadiene, 7-ethyl-1,6-octadiene, 1,6-nonadiene, 7-methyl-1,6- 1,6-dienes such as nonadiene, 4-methyl-1,6-nonadiene; 1,7-nonadiene,
Examples include 1,7-dienes such as 8-methyl-1,7-nonadiene; various non-conjugated dienes such as 1,11-dodecadiene and 1,13-tetradecadiene.

Among these, 6-methyl-1,5-hebutadiene,
6-methyl-1,5-octadiene, 6-methyl-1,
6-octadiene, 7-methyl-1゜6-octadiene, 7-ethyl-1,6-octadiene, 8-methyl-1
Branched nonconjugated dienes such as ,7-nonadiene are preferable from the viewpoint of copolymer production technology, and in particular, branched nonconjugated dienes such as 7-methyl-1,6
-Octadiene is preferred. Of course, these non-conjugated dienes can also be used in a mixture of two or more types.

. Ethylene In the polyolefin resin laminated film of the present invention, the ethylene unit in the random copolymer is essential for improving printability, but this also depends on the use of the random copolymer. It is introduced for the purpose of imparting other physical properties required for coalescence, such as transparency and flexibility, adjusting the melting point, or improving these physical properties.

Therefore, the content of ethylene units in the random copolymer is appropriately determined depending on the use of the random copolymer and other circumstances.

(b) Copolymerization The random copolymer resin used in the laminated film of the present invention is obtained by using a Ziegler-Natsuta catalyst for α-olefin polymerization, particularly a catalyst for producing crystalline polymers of α-olefins, as the monomer. It can be produced by random copolymerization of the above α-olefin, non-conjugated dienes and ethylene using the same method and apparatus as those used for producing α-olefin polymers.

(c) Composition Such a random copolymer has a content of non-conjugated diene units in the copolymer of 0. The content of ethylene units is 1 to 15 mol%, preferably 0.2 to 12 mol%, particularly preferably 0.5 to 6 mol%, and the content of ethylene units is 0.1 to 4 mol%, preferably 0.2 to 3.5 mol%. Mol%, particularly preferably from 0.5 to
It is 2 mol%. If the content of non-conjugated dienes is less than 0.1 mol%, the effect of carbon-carbon double bonds cannot be fully enjoyed because the content of unsaturated groups in the random copolymer resin is small. On the other hand, if it exceeds 15 mol%, the productivity of resin production will deteriorate, the generated random copolymer will become sticky, and the crystallinity will be too low to maintain the resin shape. There are drawbacks such as.

Furthermore, if the content of ethylene units is less than the above range, the ink adhesion will decrease, and if it exceeds the above range, the crystallinity of the random copolymer will decrease too much, and the random copolymer will no longer retain its properties as a resin. The problem arises.

(d) Physical properties The random copolymer has a degree of crystallinity (
For example, G. Natt for propylene polymer resins.
a et al., Rend, Accad, Naz, Linc
ei, 22(8).

II (+957) method) or 20
% or more, and in the case of a propylene-based random copolymer resin, it is particularly desirable that it be 25% or more.

Furthermore, the random copolymer has a melt index of 0
, 01 to 200 g/10 minutes, and particularly preferably 0.1 to 100 g/10 minutes in the present invention.

Further, the random copolymer has a melting point of 100 to 330°C, preferably 11°C at the peak melting temperature determined by DSC.
The temperature is preferably from 0 to 300°C, and in the case of a propylene random copolymer, it is preferably from 120 to 160°C. If the melting point is less than 100°C, the resin will not have sufficient heat resistance and will become a rubber-like substance.

Furthermore, the random copolymer used has properties as a resin, and such properties as a resin are usually confirmed by the flexural modulus according to J Is-720B, and the flexural modulus is 1. 000~30,000kg/
cd, preferably 1.000 to 25,000 kg/cd
In particular, in the case of a propylene random copolymer, it is common to preferably use one having a value of 1.500 to 10,000) cg/c4. The bending elastic modulus is 1,000 kg
If it is less than /c-, it will be difficult to exhibit the heat resistance of the resin, so it is unsuitable.

(e) Compounding material The surface resin film layer in the laminated film of the present invention is
It may consist only of the random copolymer, or it may consist of a mixture of the random copolymer and a polyolefin resin obtained by polymerizing at least one type of a-olefin having 3 to 12 carbon atoms. In this case, the content of non-conjugated dienes in the mixture is preferably 0.1 to 15 mol%, particularly 0.5 to 6 mol%. The polyolefin resin used in the mixture may be essentially the same as the above-mentioned polyolefin resin used in the base film layer, or in particular, ethylene resin, propylene resin, and butene-1 resin. Resins are preferred.

The surface resin film layer laminated on the base film layer can contain various auxiliary materials that are normally blended, such as antioxidants, anti-blocking agents, slip agents, antistatic agents, fillers, pigments, etc. .

[■] Production of laminated film The polyolefin resin laminated film of the present invention is prepared by adding the random copolymer to a base film layer consisting of a stretched or non-stretched single layer or laminated with other materials by a known method. It can be manufactured by laminating the composed surface resin film layers.

The base film layer may be an unstretched film formed by a T-die method, an inflation method, or the like, or a stretched film formed by a sequential biaxial stretching method, a simultaneous biaxial stretching method, or a -axial stretching method. Film can also be used. The random copolymer of the present invention is applied to one or both sides of the base film layer produced by these methods by a method represented by an extrusion lamination method, a dry lamination method, and a coextrusion lamination method (in-die and outside-die lamination methods). The laminated film of the present invention can be obtained by laminating the surface resin film layer composed of a polymer and performing a stretching operation as necessary. These forming methods can be used depending on the application and required performance of the laminated film, but either method can significantly improve the printability of the film.

[m) Characteristics of the laminated film The polyolefin resin laminated film of the present invention thus obtained has a resin film layer on the surface containing a specific resin having a C-C bond in a side chain. Based on the reactivity of this C-C bond, polar groups can be easily introduced onto the surface of the film by applying various surface treatments, which is not found in conventional polyolefin resins. It is possible to impart excellent printability, paintability, etc.

Examples of such surface treatment methods include corona discharge treatment, ultraviolet irradiation treatment, surface graft treatment, surface halogen cationic compound treatment, oxidizing agent treatment, and ozone treatment. Among these, corona discharge treatment is the preferred method because it is the easiest in terms of manufacturing technology.

[Experiment example]

EXAMPLES In order to explain the present invention in more detail, Examples and Comparative Examples will be shown below to specifically explain the present invention. .

Example 1 Production of laminated film In a polypropylene sequential biaxially stretched film forming apparatus equipped with a three-layer coextrusion die, a polypropylene homopolymer (Mitsubishi Yukagen, Mitsubishi Polypro FL6
S), and propylene (95.8 mol%), 7-methyl-1,6-octashiene (2.9 mol%) and ethylene (1.3 mol%) as resins for the surface resin film layer.
A random copolymer consisting of the following was supplied, and immediately after melt extrusion, it was cooled and solidified using a cooling roll, and then stretched 5 times vertically and then 10 times horizontally.

In the resulting three-layer laminated film, the base film layer had a thickness of 23 μm, and the surface resin film layer had a thickness of 1 μm.

Corona discharge treatment This laminated film was then subjected to a corona discharge treatment at a throughput of 00 W·min/bo.

Printing A commercially available cellophane ink (Cellocolor CC5T62 manufactured by Toyo Ink Manufacturing Co., Ltd.) was applied to this corona discharge treated film.
) was applied and dried.

Printability evaluation In order to evaluate the adhesion state of the ink on this printed laminated film, a commercially available cellophane tape was pasted on the printed side of the laminated film to avoid air bubbles, and then it was rapidly peeled off. The peeling area ratio (9o) of the ink at the time was measured.

The results are shown in Table 1.

Example 2-B Propylene as α-olefin and 7-methyl- as non-conjugated diene as resin for surface resin film layer
Example 1 except that the content of 1,6-octashiene, ethylene, and MFR were changed as shown in Table 1.
A laminated film was produced in the same manner as above, and after being subjected to a corona discharge treatment, it was printed and the printability was evaluated.

The results are shown in Table 1.

Comparative Examples 1 and 2 As resin for the surface resin film layer, propylene and 7-
Methyl-1,6-octashiene, Mat2, was produced in the same manner as in Example 1 except that a binary random copolymer of propylene and ethylene was used, and then printed after corona discharge treatment. , the printability was evaluated.

The results are shown in Table 1.

Comparative Example 3 A laminated film was prepared in the same manner as in Example 1, using the polypropylene homopolymer used as the resin for the base film layer as the resin for the surface resin film layer (i.e., a single layer consisting only of the base film layer). was molded, further subjected to corona discharge treatment, and then printed to evaluate printability.

The results are shown in Table 1.

Table 1

Claims (1)

[Scope of Claims] 1. At least one α-olefin having 3 to 12 carbon atoms and general formula (1), ▲ mathematical formula, chemical formula, table, etc. on at least one side of the base film layer made of polyolefin resin. ▼...(1) (In the formula, R^1 is an alkyl group having 1 to 8 carbon atoms, R^2, R
^3, R^4 and R^5 each independently represent a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, and n is a number of 2 to 10. A random copolymer resin of a seed and ethylene, wherein the content of the non-conjugated diene in the random copolymer resin is 0.1 to 1.
5 mol%, and a polyolefin resin laminate film comprising surface resin film layers having an ethylene content of 0.1 to 4 mol%.