JPS61254344A - Propylene polymer laminated biaxial oriented 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 biaxially stretched propylene electrolyte layered film having gas barrier properties and improved moldability and impact strength.

[Conventional technology]

Saponified ethylene-vinyl acetate copolymer (hereinafter referred to as [saponified 1
．． VAj) is widely used in the field of packaging films for foods, medicines, etc. due to its good gas barrier properties, moldability, transparency, and low water absorption (better than polyvinyl alcohol).

Since saponified EVA has high moisture permeability, it is used in multi-layered products, such as coextrusion molded products and extrusion laminate products, with polyolefin having excellent moisture resistance.

In polypropylene biaxially stretched film, saponification E
A gas barrier film is produced by co-extrusion molding with VA via an e-adhesive resin, but in this production process, recycling the recycled mixture that comes out from the so-called edges of the film makes it difficult for the film to be produced. This is unavoidable for cost reduction.

However, even if the layers and edges of a multilayer structure of polypropylene and saponified EVA are simply kneaded and molded,
Since the compatibility between the two is extremely poor, a homogeneous mixture cannot be obtained and delamination occurs, resulting in only a product with extremely poor mechanical strength and transparency. Therefore, for example, when the assembled acid product obtained in this way is recycled as one layer in coextrusion molding, it has the transparency, moldability, mechanical strength, and moisture permeation resistance required for packaging materials. It is not possible to obtain a product that has both of the above, and it has the disadvantage of reducing the value of the part.

[Problem that the invention seeks to solve]

The present inventor conducted extensive research in order to provide a propylene polymer laminated biaxially stretched film that does not have the above-mentioned drawbacks and satisfies the desired performance as a packaging material.

[Means for solving problems]

As a result, it was discovered that the above problems could be solved by laminating a layer made of the following composition on a layer of crystalline propylene polymer, and the present invention was accomplished.

That is, the present invention provides a laminated biaxially stretched film consisting of a crystalline propylene polymer layer and another layer, in which at least one of the other layers is partially or completely modified with an unsaturated carboxylic acid or an anhydride thereof. 65 to 99.1 parts by weight of a modified polyolefin having an unsaturated carboxylic acid or its anhydride content of 0.2 to 5% by weight, an ethylene content of 25 to 75 mol, and a degree of saponification of 96%.
The above saponified ethylene-vinyl acetate copolymer 35-0.
1 part by weight and the saponified ethylene-vinyl acetate copolymer 1
The present invention is a propylene polymer laminated biaxially oriented film characterized by a layer of a composition comprising 0.5 to 200 parts by weight of a plasticizer per 00 parts by weight.

The crystalline propylene polymer used in the present invention includes a homopolymer of propylene, a copolymer of a majority of the weight of propylene with other α-olefins such as ethylene and butene-1, and mixtures thereof. Mixtures with other thermoplastic resins by weight can also be used.

The modified polyolefin used in the present invention is partially or entirely modified with an unsaturated carboxylic acid or its anhydride, and the content of the unsaturated carboxylic acid or its anhydride is 0.002 to 5 F
% modified polyolefin.

Here, polyolefin refers to α-olefins having 2 to 12 carbon atoms, such as ethylene, propylene, butene-1, hexene-1,4-methylpentene-1, etc. alone or mutually copolymers, and these α-olefins and vinyl With unsaturated monomers other than α-olefins such as esters (vinyl acetate, etc.), unsaturated organic acids or derivatives other than their anhydrides (esters, amides, imides, salts, etc. of ethyl acrylate and methyl methacrylate, etc.) A copolymer of is suitable. Copolymers of α-olefins and unsaturated monomers other than α-olefins include all types of copolymers: graft, block, and random, but the α-olefin content The majority of the weight, preferably 70% by weight or more, is used.

The above polyolefin may be a mixture of two or more polyolefins.

Examples of unsaturated organic acids or anhydrides thereof for modification include acrylic acid, methacrylic acid, cinnamic acid, maleic acid, fumaric acid, itaconic acid, vinyl benzoate, maleic anhydride, and itaconic anhydride. . Among them, acrylic acid,
Maleic anhydride, especially maleic anhydride, is preferred.

As a method for graft-modifying the above-mentioned polyolefin with an unsaturated carboxylic acid or its anhydride, known methods such as introducing a polyolefin in a solution state using peroxide or the like or using a peroxide or the like in a molten state can be used. I can do it.

The produced modified polyolefin is at least partially modified with an unsaturated carboxylic acid or its anhydride. For example, a modified polyolefin into which a large amount of an unsaturated carboxylic acid or its anhydride has been grafted is replaced with an unmodified polyolefin. As a result of dilution or melting of multilayer structures,
The maleic anhydride-containing it is 0.002 to 5% by weight, preferably 0.004 to 1% by weight, and is easily obtained and has excellent economic efficiency. The content of this modifier is 0
．． If the weight is less than 002, the effect of improving the appearance of the molded product (surface unevenness, transparency, etc.) cannot be recognized, while if it exceeds 5, the mechanical strength will deteriorate and it will be economically disadvantageous, so it is not preferred do not have.

In addition, the saponified EVAilt used in the present invention contains 1125 to 75 mol of ethylene, preferably 26 to 45 mol of ethylene,
And the degree of saponification is 96% or more, preferably 98% or more. If the ethylene content is less than 5 moles, the moisture resistance will be insufficient and the oxygen permeability will be highly dependent on humidity, while if it exceeds 75 moles, the oxygen permeability will be high, which is not preferred. Moreover, those having a degree of saponification of less than 96 degrees are not preferred because they have extremely poor moisture resistance and the dependence of oxygen permeability on humidity becomes large. In addition, saponified EVA (D/L/Door o-L/
- (MFR) u, in the range of 0.1 to 20P/10 minutes.

Furthermore, the plasticizer used in the present invention is generally saponified EVA.
Compounds known as plasticizers, specifically polyhydric alcohols such as glycerin, ethylene glycol, polyethylene glycol, propylene glycol, polypropylene gelicol, and pentaerythritol: polyethylene glycol glyceryl ether Polyhydric alcohol ethers such as triethyl phosphate, trioctyl phosphate, etc.; ethanolamine and its salts such as ethanolacetamide, ethanolformamide, triethanolamine, triethanolamine acetate; succinic acid mono(β , γ-dihydroxypropyl) monocellosolve ester, glycolic acid (β,
Examples include carboxylic acid esters such as γ-dihydroxypropyl) ester. Among them, particularly preferred ratios include glycerin, triethanolamine, polyethylene glycol, polyethylene glycol glyceryl ether, and the like.

The mixing ratio of these components is modified polyolefin 65~
99.9 parts by weight, preferably 70-99 parts by weight, saponified EVA 35-0.1 parts by weight, preferably 30-1 parts by weight
Parts by weight and plasticizer are the saponified E V A 100 i
90.5 to 200 parts by weight per 1U part, preferably 1-
100 parts by weight, particularly preferably 1 to 50 parts by weight.

If the modified polyolefin is less than the above range, moldability and impact strength cannot be improved, while if it exceeds the above range, the mechanical strength will drop significantly and the economy will be disadvantageous, which is not preferable. Please note that when the saponified EVA is less than the above range, the problems that the present invention aims to solve will not occur.
It is not necessary to depend on the present invention, and on the other hand, if it exceeds the above range, moldability and impact strength will not be sufficiently improved, which is not preferable. Furthermore, if the plasticizer content is less than the above range, the moldability and impact strength will not be sufficiently improved, while if it is in excess of the above range, bleed-out or a decrease in mechanical strength will occur, which is not preferable.

In addition to these components, the composition of the present invention may contain additional resin components, rubber components, various stabilizers, nucleating agents, colorants, lubricants, fillers, etc., to the extent that the effects of the present invention are not impaired. Ingredients can be mixed. .

The above-mentioned composition in the present invention is obtained by melt-kneading the above-mentioned components in a general-purpose kneading machine. It is manufactured by blending the ingredients and melt-kneading them.

The propylene polymer laminated biaxially stretched film is produced by a general-purpose biaxial stretching method, a coextrusion method, and an in-line lamination method. The general-purpose biaxial stretching method is a sequential or simultaneous biaxial stretching method, and both the T-die method and the inflation method are possible. Specifically, for example, a molten film extruded from a T-die is solidified with a cooling roll, then stretched 3 to 8 times in the longitudinal direction with a roll at a stretching temperature of 120-150°C, and then further stretched with a tenter at a stretching temperature of 160°C. This is a method of stretching 6 to 12 times in the transverse direction at ~190°C. Furthermore, it is of course also possible to heat set the stretched film.

As described above, the lamination method may be a co-extrusion method using a raw material or an in-line lamination method.

Furthermore, in-line coextrusion lamination methods can also be used.

The laminated example in the present invention may have a structure such as a polypropylene layer/the above composite acid layer/adhesive resin layer/saponified EVA layer/adhesive resin layer, or the composition layer itself also has adhesive properties. Therefore, a configuration such as a polypropylene layer/the above composition layer/saponified EV AW composition layer is also possible.

〔Example〕

The present invention will be explained in more detail below with reference to Examples.

Examples 1 to 3, Comparative Examples 1 to 4 Polypropylene (manufactured by Mitsubishi Yuka, Mitsubishi Noblen FL6C
K, MFR2-3), polypropylene (same as above) in the blending ratio shown in Table 1, modified polypropylene (maleic anhydride content 0.2% by weight),
A composition consisting of saponified EVA (Kuraray Co., Ltd. $11EVAL-E; ethylene content: 43 molt, degree of saponification: 99%) and a plasticizer was made into a T-die with two resins and three layers so that the composition formed an intermediate layer. It was coextruded according to the method. The resin temperature at that time was 230°C. After the melt-extruded raw sheet was cooled and solidified, it was stretched 5 times in the machine direction by a roll method at a stretching temperature of 130°C. This longitudinally stretched film was subjected to in-line coextrusion lamination to obtain a 6-layer laminated film. This laminated film was stretched 9 times in the transverse direction using a tenter at a stretching temperature of 170° C., then heat set and wound up. A cross-sectional view of the layer structure of this biaxially stretched film is shown in FIG. In the figure, 1 is a polypropylene layer (6μ), 2 is a composition layer (6μ), 3 is a modified polypropylene layer (1μ), and 4 is a saponified EVA layer (5μ).

Furthermore, Table 1 shows the evaluation results of the moldability and impact strength of this film.

In the evaluation, formability is evaluated as excellent when the number of film breaks during 24 hours of continuous film forming is 0, and 1 to 3.
It is considered good if it occurs 4 times, and it is considered bad if it occurs 4 times or more. Moreover, impact strength was measured based on ASTM-D1709-75.

〔Effect of the invention〕

The propylene polymer laminated biaxially stretched film of the present invention has the transparency, moldability, mechanical strength, moisture permeability, etc. required for packaging materials as described above, and is extremely useful.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing the layer structure of a laminated film produced in an example.

Claims (1)

[Claims] In a horizontally biaxially stretched film comprising a crystalline propylene polymer layer and another layer, at least one of the other layers is
Part or all of the unsaturated carboxylic acid or its anhydride is modified, and the content of the unsaturated carboxylic acid or its anhydride is 0.
002-5% by weight of modified polyolefins 65-99.
9 parts by weight, ethylene content 25-75 mol%, saponification degree 9
6% or more saponified ethylene-vinyl acetate copolymer 35~
0.1 part by weight of a plasticizer per 100 parts by weight of the saponified ethylene-vinyl acetate copolymer. Stretched film.