JPH09193308A - Self-adhesive laminated film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a self-adhesive laminated film with excellent cutting properties, transparency, heat resistance, gas barrier properties, interlaminar adhesiveness, non-thermal shrinkage, environmental adaptability and food safety and being suitable for a packaging film. SOLUTION: This laminated film wherein an inner layer and an outer layer formed of a resin compsn. contg. 3-40 pts.wt. polybutene or polyisobutylene to 100 pts.wt. polyolefin resin are provided on both sides of a layer consisting of an ethylene-vinyl alcohol copolymer resin through an adhesive layer formed of an acid-modified polyolefin resin, is co-extrusion-molded and is drawn respectively by a draw ratio of 2-6-fold in the longitudinal direction and in the transverse direction of the original film. In addition, the whole thickness of the film is at most 40μm and the thickness of the ethylene-vinyl alcohol copolymer resin layer is 10-90 % of the thickness of the whole film.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adhesive laminated film which is suitable for food packaging. For more information,
The present invention relates to a pressure-sensitive adhesive laminated film suitable for a packaging film excellent in cuttability, transparency, heat resistance, gas barrier property, interlayer adhesion, non-heat shrinkage, environmental suitability and food safety.

[0002]

2. Description of the Related Art Heretofore, as a wrapping film used for packaging foods, a film containing polyvinylidene chloride, polyethylene or polyvinyl chloride as a main raw material has been known. However, the polyvinylidene chloride film has the disadvantage that it shrinks significantly when heated, and the polyethylene film melts when it comes into contact with oil (such as meat or tempura) and becomes hot. Further, the polyvinyl chloride film has a problem that it causes a whitening phenomenon when it comes into contact with boiling hot water.

On the other hand, an ethylene-vinyl alcohol copolymer resin is known as a resin used for a packaging film. Although this resin has excellent transparency and barrier properties, it is difficult to maintain the original physical properties of a single-layer film because of its high hygroscopicity. In addition, such a wrapping film has the following problems in cuttability (easiness of cutting). That is, the wrapping film is usually stored in a case such as a paper tube, and it is cut into an appropriate length by applying it to a cutting blade called a "saw blade" attached to the case. is there.

As this "blade" used for cutting a film, a simple blade is used which is generally made by punching a 0.2 mm thick iron plate into a saw shape. 350-70 for the case that supports
A paper box made of coated cardboard of about 0 g / m ² is used, and its rigidity is extremely low. This kind of film is required to be easily cut according to the intention of the user even with such a simple cutting mechanism, but in reality, the case and the "saw blade" are not always deformed. Instead, the film may be deformed or cutting may occur at a position outside the "saw blade". More specifically, when a conventional polyvinylidene chloride-based film is cut, if a crack is formed in a part of the film, the crack spreads,
There is a tendency to cut diagonally without being cut along the "saw blade". In addition, the conventional polyethylene-based film requires a considerable tensile force at the time of cutting, so that not only the case may be bent but the film may be deformed.

The inventors of the present invention first took up a film for lapping using an ethylene-vinyl alcohol copolymer resin, which was obtained by laminating a polyolefin resin on both sides of an ethylene-vinyl alcohol copolymer resin by a coextrusion method. It has been proposed that a pressure-sensitive adhesive laminated film having excellent heat resistance can be obtained without impairing the original properties (barrier property and transparency) of the ethylene-vinyl alcohol copolymer resin by stretching in the direction (JP-A-6- (See Japanese Patent No. 155677).

However, although the proposed method stretches the film in the machine direction (the take-up direction), and although the cut property is improved as compared with the unstretched film, it is not sufficiently satisfactory and further improvement is desired. It was rare.

[0007]

DISCLOSURE OF INVENTION Problems to be Solved by the Invention As a result of intensive studies by the present inventors, the problems of conventional wrapping films, in particular, the cuttability of a film using an ethylene-vinyl alcohol copolymer resin are further improved, The above-mentioned problems are solved by laminating a polyolefin resin on both sides of an ethylene-vinyl alcohol copolymer resin by a co-extrusion method and then biaxially stretching the original film in the longitudinal direction and the transverse direction at a specific ratio. It was found that an adhesive laminated film excellent in heat resistance, non-heat shrinkability, environmental suitability and cuttability can be obtained without impairing the original properties of ethylene-vinyl alcohol copolymer resin, and completed the present invention. It was

[0008]

In order to solve the above-mentioned problems, the invention according to claim 1 of the present invention comprises an acid-modified polyolefin resin formed on both sides of a layer comprising an ethylene-vinyl alcohol copolymer resin. After coextrusion molding a laminated film provided with inner and outer layers formed from a resin composition containing 3 to 40 parts by weight of polybutene or polyisobutylene with respect to 100 parts by weight of a polyolefin resin through an adhesive layer A film stretched at a draw ratio of 2 to 6 times in the machine direction and the transverse direction of the original film, and the total thickness of the film is 40 μm or less, and
The adhesive laminated film is characterized in that the thickness of the ethylene-vinyl alcohol copolymer resin layer is 10 to 90% of the total thickness of the film.

Hereinafter, the present invention will be described in detail. The pressure-sensitive adhesive laminated film of the present invention has a layer structure of at least 5 layers, and examples thereof include those having 5 layers of outer layer / adhesive layer / center layer / adhesive layer / inner layer. The outer layer and the inner layer of the film have at least 3 parts by weight of polybutene or polyisobutylene per 100 parts by weight of the polyolefin resin.
It is formed from a resin composition containing 40 parts by weight.

Polyolefin resin (hereinafter "(A) component")
That. ) As high pressure low density polyethylene, linear
Examples thereof include low density polyethylene and polypropylene.
Among them, polypropylene resin is heat resistant, transparent and non-heat
It is preferable in terms of shrinkability. Polypropylene resin seeds
There is no particular limitation on the type, not to mention propylene homopolymers.
It may be a copolymer of ethylene and the like and propylene.
As propylene homopolymer, isotactic poly
Propylene, syndiotactic polypropylene, Ata
You can use tactic polypropylene, but eye
Sotactic polypropylene is particularly preferred. In addition
The copolymer of ropylene and other components such as ethylene is a random copolymer.
It may be either a polymer or a block copolymer. An example
Random with propylene and 1-5 wt% ethylene
Or 1 to 10% by weight with a block copolymer or propylene
C_FourRandom or block copolymerization with the above α-olefins
An example is coalescence. In addition, this polypropylene resin
Physical properties may be selected according to various uses, conditions, etc.
Usually, melt flow rate (MFR) 0.5 to 30 g /
10 minutes, preferably 2 to 15 g / 10 minutes, density 0.89
~ 0.91 g / cm ^ThreeAre preferred. Melt flow
Rate conforms to JIS K6758, 230 ° C,
It is measured with a 2.16 kg load.

When polyethylene is used, either a homopolymer or a copolymer may be used. As the copolymer, ethylene and 1 to 10% by weight of propylene or a C ₄ or more α is used.
Random or block copolymers with olefins are used. Among these, especially MFR (JIS K675
8, 190 ° C.) is 0.5 to 30 g / 10 minutes, preferably 1.5 to 15 g / 10 minutes from the viewpoint of moldability.

Polybutene or polyisobutylene (hereinafter referred to as "component (B)") acts as a thickener and imparts excellent tackiness to the film. The compounding amount of this polybutene or polyisobutylene is 3 to 40 parts by weight, preferably 10 to 25 parts by weight with respect to 100 parts by weight of the polyolefin resin as the component (A). If the compounding amount is less than 3 parts by weight, sufficient tackiness is not exhibited, and conversely, if it exceeds 40 parts by weight, a large amount of bleeding causes tackiness and heat resistance is deteriorated, which is not preferable. In addition,
The physical properties of the polybutene or polyisobutylene used here can be appropriately determined depending on the blending amount, the type of other components, the intended use of the composition, etc., but is not particularly limited, but usually the number average molecular weight of 200 to Those in the range of 5,000, preferably 400 to 4,000 are preferable.

In the present invention, it is preferable to use a polyglycerin fatty acid ester (hereinafter referred to as "component (C)") in combination with the component (B), polybutene or polyisobutylene, because the tackiness of the film is increased. This polyglycerin fatty acid ester means that at least one of the hydroxyl groups of the condensation polymer of glycerin has 8 to 2 carbon atoms.
2 is a compound esterified with a fatty acid such as a higher fatty acid. Here, the degree of polymerization of the glycerin condensation polymer is usually 2 to
It is a condensation polymer of 10, preferably 2 to 6. Among the hydroxyl groups of the glycerin condensation polymer, the number of esterified hydroxyl groups is 1 or more, preferably 1 or more and 70% or less of the number of hydroxyl groups, more preferably 1 or more and 60% of the number of hydroxyl groups. It is the following. Higher fatty acid has 8 to 22 carbon atoms
The above fatty acid may be saturated or unsaturated and is usually preferably a fatty acid having 10 to 18 carbon atoms. Examples of the polyglycerin fatty acid ester include diglycerin monolaurate, diglycerin monopalmitate, diglycerin monooleate, diglycerin monostearate, diglycerin dioleate, triglycerin monooleate and the like.

Of course, two or more kinds of these polyglycerin fatty acid esters may be used in combination. The amount of the polyglycerin fatty acid ester blended is 0.2 to 10 parts by weight with respect to 100 parts by weight of the polyolefin resin as the component (A),
It is preferably 1 to 6 parts by weight. If the blending amount is less than 0.2 parts by weight, the synergistic effect with the polybutene or polyisobutylene as the component (B) does not occur. On the contrary, if it exceeds 10 parts by weight, a large amount of bleeding causes stickiness and odor, and However, gel is often generated, which is not preferable.

Further, in the present invention, a glyceride having an acyl group having 2 to 6 carbon atoms and an acyl group having 8 to 22 carbon atoms (hereinafter referred to as "component (D)") may be used in combination. The glyceride as used in the present invention means that one of the three hydroxyl groups of glycerin is a lower fatty acid having 2 to 6 carbon atoms and the other one is esterified with a higher fatty acid having 8 to 22 carbon atoms. Is required, and the other one remains a hydroxyl group or is a diacetin compound or triacetin compound esterified with a lower fatty acid having 2 to 6 carbon atoms or a higher fatty acid having 8 to 22 carbon atoms (hereinafter referred to as "hybridized"). "Glyceride"). The acyl groups of the triacetin compound may of course all be different. The higher fatty acid may be saturated or unsaturated as long as it is a fatty acid having 8 to 22 carbon atoms, and is usually a fatty acid having 10 to 18 carbon atoms. The lower fatty acid may be any one having 2 to 6 carbon atoms.

Examples of the glyceride of the present invention include, for example, diacetyl monolauryl glycerin, diacetyl monopalmityl glycerin, diacetyl monooleyl glycerin, monoacetyl dilauryl glycerin, monoacetyl monopalmityl glycerin, monoacetyl dioleyl glycerin, monoacetyl. Monolauryl glycerin, monoacetyl monooleyl glycerin, dipropionyl monolauryl glycerin, dicaproyl monolauryl glycerin, dicaproyl monopalmityl glycerin, monoacetyl monocapryl glycerin, monoacetyl monobrassyl glycerin, monopropionyl monobrassyl glycerin , Monoacetyl monoerucyl glycerin and the like. Particularly, diacetyl monolauryl glycerin and diacetyl monooleyl glycerin are preferable.

Of course, two or more kinds of these mixed glycerides may be used in combination. The film formed from the olefin resin composition containing the glyceride of the present invention has good adhesiveness and can easily adhere to an object without pressure bonding. At the same time, the peeling property between the films is also improved, and the film can be easily fed out during use.

The blending amount of the glyceride of the present invention is 0. 100 parts by weight with respect to 100 parts by weight of the polyolefin resin which is the component (A).
It is 1 to 10 parts by weight, preferably 1.0 to 5.0 parts by weight. If the blending amount is less than 0.1 parts by weight, the effect of imparting tackiness is not sufficient, and conversely, if it exceeds 10 parts by weight, the resulting film becomes sticky or markedly slips, and the workability is deteriorated.

The adhesive layers (inner layer and outer layer) formed of the above-mentioned polyolefin resin composition are provided on the central layer formed of the ethylene-vinyl alcohol copolymer resin via the adhesive layer. As such an ethylene-vinyl alcohol copolymer resin, one having an MFR of 1 to 20 g / 10 min (230 ° C.) is usually used. From the viewpoint of moldability, it is preferably 1 to 10 g / 10 minutes, more preferably 2 to 7 g / 10 minutes. MFR is 1g / 1
If it is less than 0 minutes, the extrudability is poor, and conversely, if it exceeds 20 g / 10 minutes, the film forming stability is lowered. Further, the ethylene content in the ethylene-vinyl alcohol copolymer resin also greatly affects the performance, and is preferably 20 to 60 mol%, more preferably 25.
˜50 mol% is desirable.

If the content is less than 20 mol%, problems with water resistance and extrudability occur, whereas if it exceeds 50 mol%, barrier properties and transparency deteriorate. The acid-modified polyolefin resin constituting the adhesive layer of the present invention can be obtained by graft-reacting an acid such as unsaturated carboxylic acid or its derivative with the base polyolefin resin by an arbitrary method.

For example, a method of reacting a polyolefin and an unsaturated carboxylic acid in a molten state (for example, Japanese Patent Publication No.
3-27421), a method of reacting in a solution state (for example, Japanese Examined Patent Publication No. 44-15422), a method of reacting in a slurry state (for example, Japanese Examined Patent Publication No. 43-18144), a method of reacting in a gas phase state (for example, JP-A No. 50-77493
No.). Among these methods, the melt-kneading method using an extruder is preferable because it is simple in operation.

As the raw material of the acid-modified polyolefin resin, for example, polyethylene, polypropylene or the like is used. The resin is not particularly limited, and polyethylene and polypropylene homopolymers and copolymers are used. The range of preferable physical properties of those polymers is preferably the same as that of the polyolefin used for the inner and outer layers described above.

Moreover, it is preferable to use the same raw material as the inner and outer layers from the viewpoint of the adhesive force between the inner and outer layers and the adhesive layer and the formability.
Examples of unsaturated carboxylic acids used for modifying the polyolefin of the adhesive layer include acrylic acid, methacrylic acid,
Maleic acid, fumaric acid, itaconic acid, citraconic acid, and their acid anhydrides, esters, amides, imides, metal salts and the like, of which maleic anhydride is most preferable.

An organic peroxide is used to accelerate the reaction between the polyolefin and the unsaturated carboxylic acid.
Examples of the organic peroxide include benzoyl peroxide, lauroyl peroxide, azobisisobutyronitrile, dicumyl peroxide, α, α′-bis (t-butylperoxydiisopropyl) benzene,
2,5-dimethyl-2,5-di (t-butylperoxy) hexane, 2,5-dimethyl-2,5-di (t-butylperoxy) hexyne-3, di-t-butylperoxide, Cumene hydroperoxide, t-butyl hydroperoxide and the like can be mentioned. The amount of the organic peroxide added is not particularly limited, but is usually 0.005 to 5 parts by weight, preferably 0.01 to 1 part by weight, based on 100 parts by weight of the polyolefin.

The acid-modified polyolefin resin grafted with unsaturated carboxylic acids is the polyolefin shown above,
Unsaturated carboxylic acids and organic peroxides are thoroughly mixed with a tumbler, a Henschel mixer, etc., and melt-kneaded at a temperature not lower than the melting point of the polyolefin, generally not lower than the melting point and not higher than 280 ° C. to carry out a grafting reaction. The method of melt-kneading is not particularly limited, and for example, a screw extruder, a Banbury mixer, a mixing roll or the like can be used, but a screw extruder is preferably used because of the ease of operation. The temperature and time of melt-kneading vary depending on the decomposition temperature of the organic peroxide used, but generally 160
To 280 ° C. for 0.3 to 30 minutes, preferably 170
It is suitable to be at 1 to 10 minutes at 1 to 250 ° C.

The graft amount of unsaturated carboxylic acids in the acid-modified polyolefin resin is 0.01 to 3% by weight, preferably 0.03 to 1% by weight. When the graft amount of unsaturated carboxylic acids is 0.01% by weight or less, the adhesiveness is lowered,
If it is 3% by weight or more, the gelled product tends to increase, which is not preferable. In the present invention, the acid-modified polyolefin resin preferably contains an acid-modified polyolefin elastomer, and is 2% by weight or more, preferably 5 to 50% by weight, and particularly preferably 10 to 25% by weight. Adhesiveness can be improved by containing.

Examples of the raw material for such an acid-modified polyolefin elastomer include ethylene and α having 3 or more carbon atoms.
A copolymerized elastomer with an olefin is used. Among them, the density is less than 0.91 g / cm ³ , preferably 0.1.
85 ~ 0.90g / cm ³ , MFR 0.1 ~ 50g
/ 10 minutes (ASTM-D1238, 190 ° C.), preferably 1 to 20 g / 10 minutes.

Α having 3 or more carbon atoms to be copolymerized with ethylene
Examples of the olefin include propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene and the like, together with them, non-conjugated dienes such as 1,4-hexadiene, dicyclopentadiene and ethylidene norbornene. It can also be used. The ethylene-α-olefin copolymer elastomer is obtained by copolymerizing ethylene and α-olefin using a Ziegler type catalyst, especially a catalyst composed of a vanadium compound such as vanadium oxytrichloride and vanadium tetrachloride and an organic aluminum. It is desirable that the ethylene content of the elastomer is in the range of 40 to 90 mol% and the α-olefin content is in the range of 10 to 60 mol%. Examples of commercially available ethylene-α-olefin copolymer elastomers include CdF Chimie.
E. FIG. P. NORSOFLEX (FW1600, FW
1900, MW1920, SMW2440, LW222
0, LW2500, LW2550); Flex resin (DFDA1137, DFDA113 of Nippon Unicar Co., Ltd.)
8, DEFD1210, DEFD9042); Tuffmer (A4085, A4090, P018 of Mitsui Petrochemical Co., Ltd.
0, P0480), JSR-EP (E of Japan Synthetic Rubber Co., Ltd.
P02P, EP07P, EP57P) and the like.

The acid modification of these elastomers can be carried out in the same manner as the acid modification of the above-mentioned polyolefin resin.
In the present invention, the acid modification treatment may be simultaneously performed while kneading the unmodified polyolefin resin and the elastomer. In the present invention, the acid-modified polyolefin resin may further be mixed with up to 2000 parts by weight of an unmodified polyolefin resin with respect to 100 parts by weight of the resin. At this time, it is preferable to mix the unsaturated carboxylic acids in the mixture so that the graft amount of the unsaturated carboxylic acids falls within the above range. Examples of the unmodified polyolefin resin include polypropylene and polyethylene, which are raw materials of the acid-modified polyolefin resin described above.

Further, it is desirable to mix the ethylene-vinyl alcohol copolymer resin with the above acid-modified polyolefin resin because the adhesiveness is improved. The physical properties of the ethylene-vinyl alcohol copolymer resin are preferably the same as those described above. The ethylene-vinyl alcohol copolymer resin is 2 to 40% by weight in the obtained resin composition,
Preferably, they are mixed so as to be 10 to 25% by weight.
If it is out of these ranges, the effect of improving the adhesiveness and the transparency is lowered.

Furthermore, in the resin composition of the present invention, a heat stabilizer, a weather stabilizer, a lubricant, an antistatic agent, a nucleating agent, a filler, a pigment, a dye, a flame retardant and an antiblocking agent, which are usually used. Additives such as 0.0005 to 30% by weight may be contained. When the ethylene-vinyl alcohol copolymer resin is mixed with the acid-modified polyolefin resin, a general method may be used for mixing them, but there is no particular limitation, but in order to improve transparency, the specific energy relative to the resin is 0.3.
kw · hr / kg or more, preferably 0.4 to 2.0 k
It is desirable to perform melt mixing under the condition of w · hr / kg.
For example, an acid-modified polyolefin resin and an ethylene-vinyl alcohol copolymer resin are mixed under the above conditions under the conditions of 190 to 3
Melt and mix at 50 ° C. with a screw extruder, a Banbury mixer, a mixing roll, or the like.

When the acid-modified polyolefin resin and the ethylene-vinyl alcohol copolymer resin are melt-mixed under such a condition, the ethylene-vinyl alcohol copolymer resin is dispersed in the acid-modified polyolefin resin in a micro size and uniformly, so that the transparency is improved. Is significantly improved. Here, the specific energy refers to (1 k
The energy given to the resin of g) from the kneading equipment for the effect of kneading, and the higher the value, the higher the kneading effect.

For example, in the case of an extruder, it is approximately represented by the power consumption of the screw driving motor required to extrude 1 kg of resin. In the case of a roll-type kneader such as a Banbury mixer, it can be approximately represented by the power consumption of a roll driving motor required for treating 1 kg of resin. Specifically, attach an ammeter, voltmeter, etc. to the motor of the extruder, obtain the power consumption of the motor from this, and multiply it by the power factor of the motor (usually about 0.85) to obtain 1 kg.
The kneading force (kw · hr / kg) applied to the resin of (1) is obtained.

In practice, an acid-modified polyolefin resin and an ethylene-vinyl alcohol copolymer resin are mixed in an amount of 200 to 3
Melt and mix at 50 ° C. with a screw extruder, a Banbury mixer, a mixing roll, or the like. The pressure-sensitive adhesive laminated film of the present invention has a layer structure of 5 layers of 3 types by specific coextrusion molding of the above-mentioned adhesive polyolefin resin, ethylene-vinyl alcohol copolymer resin and acid-modified polyolefin resin, for example, [polypropylene resin / Acid-modified polyolefin resin / ethylene-vinyl alcohol copolymer resin / acid-modified polyolefin resin / polypropylene-based resin] is co-extruded, and then the film is biaxially stretched in the machine direction and the transverse direction to form the film. To be done.

As the coextrusion molding, a T-die molding method or a water-cooled inflation molding method is adopted. That is, by rapidly cooling the melt-extruded resin by the above-mentioned molding method, a film having more excellent transparency can be obtained as compared with the air-cooled inflation molding method which is usually used. The unstretched multilayer film obtained by the coextrusion molding is then biaxially stretched in both the longitudinal and transverse directions of the film at a stretching ratio of 2 to 6 times, preferably 2.5 to 4 times. If the stretching ratio is less than 2 times, the cuttability of the film is insufficient, and if it is more than 6 times, the stretching property is lowered, and the film may be broken or the film may be unevenly stretched, which is not desirable. In the longitudinal stretching process in the case of sequential biaxial stretching, the unstretched film is heated as it is or slit into a predetermined width and heated, for example, by changing the peripheral speed of a stretching roll to stretch the film in the drawing direction, that is, the longitudinal direction. It is performed by the method. As the preheating temperature in the stretching treatment,
Usually, the melting point of the polyolefin resin is not higher than -20 ° C, preferably 40 to 120 ° C.

On the other hand, the transverse stretching treatment is generally carried out in a facility called a tenter stretching machine. The preheating temperature is usually [melting point of polyolefin resin −10 ° C.] or lower,
Desirably, the temperature is in the range of 70 to 140 ° C. The heat setting temperature after stretching is higher than the preheating temperature, and is preferably as high as possible in order to prevent wrinkles and non-heat shrinkage of the film, and is usually 10 ° C. higher than the melting point of the polyolefin resin. A slightly lower temperature is used, and specifically, it is preferably carried out in the range of 80 to 150 ° C.

When the preheating and heat setting temperatures are higher than the suitable temperature, the film melts and adheres to the longitudinal stretching rolls, and when the preheating temperature is lower than the suitable temperature, the ethylene-vinyl alcohol copolymer resin is insufficiently preheated. Because of this, stretching becomes difficult and film breakage occurs, which is not desirable. In addition to the sequential biaxial stretching method described above, the simultaneous biaxial stretching method can be applied, and there are a tenter system and a tubular system, but the preheating temperature and the heat setting temperature are the same. By carrying out this stretching step, the cuttability of the film is greatly improved, and the film can be cut to a desired length with a light force using a saw blade.

The thickness of the pressure-sensitive adhesive laminated film of the present invention is 40 μm or less, preferably 2 to 30 μm, more preferably 5 to 20 μm, and the thickness of the central layer is 10 to 90% of the total thickness of the film. Is the range.
When the thickness of the film is larger than 40 μm, the tear strength at the time of cutting the film becomes too large, which is unsuitable for use as a wrap film.

If the thickness of the central layer is less than 10% of the total thickness, the original transparency and barrier properties of the ethylene-vinyl alcohol copolymer resin cannot be maintained. The thickness of the central layer is preferably 15% or more of the total thickness. On the other hand, when it is more than 90%, the thickness of the polyolefin layer becomes thin, and it becomes difficult to uniformly cover the central layer by coextrusion molding. The thickness of the central layer is preferably 80% or less of the total thickness. The adhesive laminated film of the present invention is used for various packaging applications such as food packaging.

[0040]

EXAMPLES Hereinafter, specific embodiments of the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples as long as the gist thereof is not exceeded.
The measurements in the examples were carried out by the following methods. (1) Moisture Permeability According to JIS Z0208, it was measured under the conditions of 40 ° C. and 90% RH. (2) Transparency Measured using a transparency measuring device manufactured by Murakami Color Research Laboratory. Three kinds of measured values, MAX value, MIN value, and AVE value, are obtained, but the MAX value corresponding to the visual feeling is displayed. (3) Heat-resistant temperature A strip-shaped film having a width of 30 mm and a length of 14 cm, a piece of paper is placed 25 mm above and below the sample piece, and a 10 g weight is lowered. The maximum atmospheric temperature that could not be cut in one hour was measured in steps of 10 ° C.

(4) Heat Shrinkage A film having a diameter of 10 mm was made into a sample by a punching jig,
This is dipped in an aluminum pan containing silicone oil, and this aluminum pan is placed on a hot plate at 140 ° C. Although the temperature of the hot plate once drops because the aluminum pan draws heat, the sample is taken out 45 seconds after the temperature reaches 140 ° C. and the change in size is measured. (5) Cutability US TESTING MACHINES INC. The easiness of tearing of the film was evaluated using a PPT tear tester (trade name) manufactured by the company. In this test, a weight with a constant load equipped with a needle was dropped from a certain height on a film sample, and the easiness of tearing was quantified by the length of the film torn. The tear length is measured by setting the sample so that the tear enters the lateral direction of the film. The larger the split length, the lighter the blade can cut. It can be said that the sample has a good cutting property. Measurement conditions: load 30g, drop height 5
0 cm.

(6) Adhesive Strength The adhesive strength between the adhesive layer (acid-modified polyolefin resin) and the central layer (ethylene-vinyl alcohol copolymer resin), which is a problem in the film of the present invention, was evaluated. (7) Adhesive strength Lightly stack two films and put 25
Linear pressure 0.3kg / c with roll of mmφ and width of 150mm
The force required for shearing and peeling two films within 5 minutes and for peeling in the direction of 180 ° C. was measured with an Instron type tensile tester by pressurizing 3 times with m ² . Table 1 shows the conditions.

[0043]

[Table 1]

(8) Oxygen permeation amount According to JIS K7126, it was measured under the conditions of 20 ° C. and 65% RH.

Example 1 Using a 450 mm wide three-kind five-layer coextrusion T-die molding machine, Table 2
The resin shown in 3 is simultaneously extruded from three extruders at a die temperature of 280 ° C., a chill roll temperature of 25 ° C., and a take-up speed of 10 m /
The film was formed under the conditions of minutes, and the three types of five-layer film (thickness 30 μm, layer ratio 1: 1: 1: 1, consisting of outer layer / adhesive layer / center layer / adhesive layer / inner layer, consisting of the raw material composition of layers shown in Table 2 was used. 1) was molded. Then, the film is roll-stretched at a preheating temperature of 6
At 0 ° C, the film was stretched 3.5 times in the machine direction, then stretched 3.5 times in the transverse direction at a preheating temperature of 100 ° C by tenter stretching, and finally heat set at a heat setting temperature of 130 ° C. The moisture permeability, transparency, heat resistant temperature, heat shrinkage rate and cuttability of the obtained film were evaluated by the above methods. Table 6 shows the results.

[0046]

[Table 2]

In Table 2, polypropylene: propylene-ethylene random copolymer, manufactured by Mitsubishi Chemical Co., Ltd., Mitsubishi Polypro MG3, MFR;
9g / 10 minutes (230 ° C), density (ρ); 0.9g / c
m ³ polybutene: Nippon Petrochemical Co., Ltd., Nisseki Polybutene H
V-35, average molecular weight 750 Modified polypropylene: 100 parts by weight of Mitsubishi Polypro MG3, 1 part by weight of maleic anhydride, 2,5-dimethyl-
0.15 parts by weight of 2,5-di (t-butylperoxy) hexyne-3 was melt-kneaded at 210 ° C. in a 50 mmφ extruder to pelletize a modified polypropylene. The amount of maleic anhydride grafted on the modified polypropylene was 0.35% by weight.

EVOH (ethylene-vinyl alcohol copolymer resin): manufactured by Nippon Synthetic Chemical Industry Co., Ltd., trade name: Soarnol, ET3803, ethylene content: 38 mol
%, MFR; 4.0 g / 10 minutes (230 ° C.) Diglycerin monooleate: Riken Vitamin Co., Ltd., Rikemal O-71-DE Diacetylmonolauryl glycerin: Riken Vitamin Co., Ltd., Poem G-002

Example 2 In Example 1, the layer ratio of the multilayer film was 3: 1 :.
A film was obtained in the same manner except that the ratio was 2: 1: 3. Table 6 shows the results. Example 3 In Example 1, the raw fabric molding was water-cooled inflation molding with a cooling water temperature of 30 ° C. and the stretching method was tubular 2.
Axial stretching method, preheating temperature of 110 ° C, heat setting temperature of 13
A film was obtained in the same manner except that the temperature was 0 ° C. Table 6 shows the results.

Example 4 The multilayer film obtained in Example 1 was pulverized and then pelletized with a single-screw extruder at a specific energy of 0.5 kw · hr / kg to obtain a recycled raw material. A film was obtained in the same manner as in Example 1 except that this recycled material was used for the adhesive layer. Table 6 shows the results. This shows that the performance is excellent even if the loss is collected and recycled.

Example 5 A film was obtained in the same manner as in Example 1 except that the inner and outer layers and the adhesive layer had the raw material compositions shown in Table 3.
Table 6 shows the results.

[0052]

[Table 3]

In Table 3, linear low density polyethylene: manufactured by Mitsubishi Chemical Corporation, Mitsubishi Polyethylene, UF340, MFR; 2.0 g / 10 min (190
C), ρ; 0.922 g / cm ³ modified low density polyethylene: Mitsubishi Polyethylene, 100 parts by weight of UF340, 1 part by weight of maleic anhydride, 2,5-dimethyl-2,5-di (t-butylperoxy). ) 0.15 parts by weight of hexyne-3 was used for 19 mm in a 50 mmφ extruder.
The mixture was melt-kneaded at 0 ° C. and pelletized to obtain a modified low density polyethylene. The modified low-density polyethylene had a maleic anhydride graft amount of 0.35% by weight.

Example 6 A film was obtained in the same manner as in Example 1 except that the adhesive layer had the raw material composition shown in Table 4. Table 6 shows the results.

[0055]

[Table 4]

In Table 4, modified polypropylene: Mitsubishi Polypro MG3 80 parts by weight, trade name; Tuffmer A4085 (manufactured by Mitsui Petrochemical Industry Co., Ltd.), MFR 3.6 g / 10 min (190 ° C.),
ρ; 20 parts by weight of 0.88 g / cm ³ , 1 part by weight of maleic anhydride, and 0.15 parts by weight of 2,5-dimethyl-2,5-di (t-butylperoxy) hexyne-3 50
Melt-kneading was carried out at 210 ° C. with an mmφ extruder to pelletize the modified polypropylene. The amount of maleic anhydride grafted on the modified polypropylene was 0.35% by weight.

Example 7 A film was obtained in the same manner as in Example 1 except that the adhesive layer had the raw material composition shown in Table 5. Table 6 shows the results.

[0058]

[Table 5]

Example 8 A film was obtained in the same manner as in Example 1, except that the composition of only polypropylene / polybutene = 100/20 (parts by weight) was used as the inner and outer layers. Table 6 shows the results. Example 9 The multilayer film obtained in Example 1 was pulverized and then pelletized with a single-screw extruder under conditions of a specific energy of 0.2 kw · hr / kg to obtain a recycled raw material.

A film was obtained in the same manner as in Example 1 except that this recycled material was used for the adhesive layer. Table 6 shows the results. Comparative Examples 1 to 4 Films were obtained in the same manner as in Example 1 except that the film thickness, film layer ratio and draw ratio shown in Table 6 were used. Table 6 shows the results.

Comparative Example 5 In Example 1, stretching was carried out only in the longitudinal stretching (preheating temperature 60
A film was obtained by the same method except that the temperature was set at 0 ° C and the heat setting temperature was 110 ° C. Table 6 shows the results.

[0062]

[Table 6]

[0063]

EFFECT OF THE INVENTION The adhesive laminated film of the present invention has the following special advantageous effects and has an extremely great industrial utility value. (1) The adhesive laminated film of the present invention is excellent in cuttability, transparency, interlayer adhesion, heat resistance, barrier property, non-heat shrinkability and food safety.

(2) In the pressure-sensitive adhesive laminated film of the present invention, nonstandard products, defective products, etc., which are generated when the pressure-sensitive adhesive laminated film of the present invention is produced, can be used as recycled products, Economical in productivity and cost. (3) The pressure-sensitive adhesive laminated film of the present invention does not generate harmful gases such as NO _X and hydrogen chloride, which are nowadays a problem, when the plastic film is incinerated for disposal after use. So it is also environmentally superior.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shinji Kawasaki 3-10-10 Shiodotsu, Kurashiki-shi, Okayama Mitsubishi Chemical Corporation Mizushima Development Laboratory

Claims (4)

[Claims] 1. Polybutene or polyisobutylene is added to 100 parts by weight of a polyolefin resin through an adhesive layer formed of an acid-modified polyolefin resin on both sides of a layer made of an ethylene-vinyl alcohol copolymer resin.
After co-extrusion molding a laminated film provided with inner and outer layers formed of a resin composition containing 40 to 40 parts by weight, the film is stretched in the machine direction and the transverse direction at a draw ratio of 2 to 6 times, respectively. The entire thickness of the film is 40 μm or less, and the thickness of the ethylene-vinyl alcohol copolymer resin layer is 10 to 10 times the total thickness of the film.
90% of the pressure-sensitive adhesive laminated film. 2. The pressure-sensitive adhesive laminated film according to claim 1, wherein the adhesive layer contains an ethylene-vinyl alcohol copolymer resin. 3. The pressure-sensitive adhesive laminated film according to claim 1, wherein the adhesive layer contains an acid-modified polyolefin elastomer. 4. The adhesive layer is formed by melt-kneading an acid-modified polyolefin resin, an ethylene-vinyl alcohol copolymer resin and / or an acid-modified polyolefin elastomer under conditions of a specific energy of 0.3 kw · hr / kg or more. The adhesive laminated film according to claim 1, wherein the adhesive laminated film is