JPH06155677A - Self-adhesive laminated film - Google Patents

Abstract

PURPOSE:To obtain the title film excellent in cutting properties, heat resistance, heat non-shrinkability, environmental aptitude and food safety by providing a self-adhesive layer composed of a resin compsn. of a polyolefin resin and a polybutene resin to both surfaces of an ethylene/vinyl alcohol copolymer resin layer through an acid modified polyolefin resin adhesive layer by co- extrusion molding and stretching the obtained laminate in a taking-up direction. CONSTITUTION:A self-adhesive laminated film has five-layered constitution and constituted of, for example, five-layered constitution of outer layer/adhesive layer/center layer/adhesive layer/inner layer. Adhesive layers formed from an acid modified polyolefin resin are provided to both surfaces of an ethylene/ vinyl alcohol copolymer layer. Self-adhesive layers formed from a resin compsn. containing 3-40 pts.wt. of polybutene or polyisobutylene with respect to 100 pts.wt. of the polyolefin resin are provided to the adhesive layers to form a laminated film. This laminated film can be stretched in stretching magnification of 2-6 times in a film taking-up direction after co-extrusion molding. The total thickness of the film is set to 40mum or less and the thickness of the ethylene/ vinyl alcohol resin layer is set to 10-90% with respect to the total thickness.

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 and the like. More specifically, the present invention relates to a pressure-sensitive adhesive laminated film suitable for a packaging film having excellent cuttability, transparency, heat resistance, gas barrier property, interlayer adhesiveness, non-heat shrinkage property, 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.

[0003]

However, the polyvinylidene chloride-based film has a disadvantage that it shrinks greatly when heated, and the polyethylene-based film is in contact with oily substances (for example, meat and tempura) and has high heat. In the case of the above, there is a drawback that the film is melted, and the polyvinyl chloride film has a problem that a whitening phenomenon occurs 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.

[0006]

Means for Solving the Problems The present inventor has conducted extensive studies to provide an adhesive laminated film capable of obtaining a packaging film in which the above-mentioned problems of the conventional wrapping film have been solved. -A vinyl alcohol copolymer resin (hereinafter sometimes referred to as EVOH) on both sides of which a polyolefin resin is laminated by a co-extrusion method is stretched in the film-drawing direction to solve the above-mentioned problems, and ethylene. -It is possible to obtain an adhesive laminated film excellent in cuttability, heat resistance, non-heat shrinkage, environmental suitability and food safety without impairing the original properties (barrier property and transparency) of vinyl alcohol copolymer resin. And found the present invention.

That is, the gist of the present invention is that polybutene or polybutene is added to 100 parts by weight of a polyolefin resin through adhesive layers formed of an acid-modified polyolefin resin on both sides of a layer made of an ethylene-vinyl alcohol copolymer resin. Obtained by co-extrusion molding a laminated film provided with an adhesive layer formed from a resin composition containing 3 to 40 parts by weight of polyisobutylene, and then stretching the film in a drawing direction at a draw ratio of 2 to 6 times. A pressure-sensitive adhesive laminated film,
The adhesive laminated film is characterized in that the total thickness of the film is 40 μm or less, and the thickness of the ethylene-vinyl alcohol copolymer resin layer is 10 to 90% of the total thickness of the film.

The present invention will be described in detail below. 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")
Say. ) 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. Further
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 ³Are 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 blending 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 stickiness and heat resistance is lowered, 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 polybutene or polyisobutylene as component (B) 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. Of 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 fatty acid may be saturated or unsaturated, and is 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 and triglycerin monooleate.

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 "(D) component") 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, these mixed glycerides may be used in combination of two or more kinds. 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 is easily fed out when it is used.

The amount of the glyceride of the present invention to be blended is 0.1 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, and 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 with 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.) etc. 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 that for 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 elastomer, and is preferably 2% by weight or more, preferably 5 to 50% by weight, particularly preferably 1% by weight.
Adhesion can be improved by containing 0 to 25% by weight of the acid-modified polyolefin elastomer.

Examples of raw materials 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. 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.

In addition, the above acid-modified polyolefin resin is added with E
Mixing a VOH resin is desirable because it improves the adhesiveness. The physical properties of the EVOH resin are preferably the same as those described above. The EVOH resin is contained in the resulting resin composition in an amount of 2 to 40% by weight, preferably 10 to 2%.
Mix so as to be 5% 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. EVOH for acid-modified polyolefin resin
When the resins are mixed, a general method may be used for mixing them, and there is no particular limitation, but in order to improve transparency, the specific energy for the resin is 0.3 kw · hr / kg or more, preferably 0.4 It is desirable to melt-mix under the condition of ~ 2.0 kw · hr / kg. For example, an acid-modified polyolefin resin and an EVOH resin are mixed under the above conditions under the conditions of 190-90.
Melt and mix at 350 ° C. with a screw extruder, a Banbury mixer, a mixing roll, or the like.

When the acid-modified polyolefin resin and the EVOH resin are melt-mixed under such conditions, the EVOH resin has a micro size and is uniformly dispersed in the acid-modified polyolefin resin, and the transparency is remarkably improved. Here, the specific energy refers to (1 k
It means the energy given to the resin of g) from the kneading equipment for the effect of kneading, and when the value is large, the kneading effect is high.

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, acid-modified polyolefin resin and E
VOH is melt-mixed at 200 to 350 ° 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 layered structure of 5 layers of 3 types by specific coextrusion molding of the above-mentioned adhesive polyolefin resin, EVOH resin and modified resin, for example, [polypropylene resin / modified resin / EVOH resin / modified. resin/
Polypropylene resin] is formed by co-extrusion molding a multilayer film and then uniaxially stretching the film in the take-up direction (longitudinal direction).

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 above coextrusion molding is then uniaxially stretched in the film-drawing direction (longitudinal direction) 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.
The stretching treatment is carried out by heating the unstretched film as it is or slitting it into a predetermined width and stretching the film in the take-up direction, that is, the longitudinal direction by changing the peripheral speed of a stretching roll. The preheating temperature in the stretching treatment is usually [melting point of polyolefin resin −20 ° C.] or less, preferably in the range of 40 to 120 ° C.

The heat setting temperature after stretching is preferably higher than the preheating temperature, and is preferably as high as possible in order to prevent wrinkles of the film and improve lateral strength. Melting point −20 ° C.] or less, preferably in the range of 80 to 150 ° C. When the preheating and heat setting temperatures are higher than [melting point of polyolefin resin-20 ° C], the film melts and adheres to the stretching roll, and when the preheating temperature is less than 40 ° C, E
The VOH resin is not desirable because it is difficult to stretch due to insufficient preheating and film breakage occurs.

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 the total thickness of the film. It is in the range of 90%. 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.

When the thickness of the central layer is less than 10% of the total thickness, the original transparency of the EVOH resin cannot be maintained, and the physical properties of the uniaxially stretched polyolefin film become dominant, so the stretching direction It is easy to tear. 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 8 of the total thickness.
It is preferably 0% or less. The adhesive laminated film of the present invention is used for various packaging applications such as food packaging.

[0038]

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 weight of 10 g 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 The film was wound on a core tube, housed in a case for wrapping film, and a cutting test was carried out with this blade, and evaluation was made according to a four-step level (good, normal, somewhat poor, and poor). As a standard for evaluation, the cut level of a commercially available wrap film was evaluated as normal. (6) Adhesive Strength The adhesive strength between the adhesive layer (modified resin) and the central layer (EVOH), 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 the 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 . The conditions are shown in Table 1.

[0040]

[Table 1]

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 /
3 types consisting of outer layer (polypropylene) / adhesive layer (modified resin) / center layer (EVOH resin) / adhesive layer (modified resin) / inner layer (polypropylene)
Layer film (thickness 30 μm, layer ratio 1: 1: 1: 1: 1)
Was molded. Then, the film was stretched 3.5 times in the machine direction by roll stretching at a preheating temperature of 60 ° C. and a heat setting temperature of 110 ° C. The moisture permeability, transparency, heat resistant temperature, heat shrinkage rate and cuttability of the obtained film were evaluated by the above methods. Table 2 shows the composition of the raw materials used. The results are shown in Table 6.

[0042]

[Table 2]

Polypropylene: Propylene-ethylene random copolymer, manufactured by Mitsubishi Kasei Co., Ltd., Mitsubishi Polypro 65
00J, MFR; 9 g / 10 minutes (230 ° C.), density (ρ); 0.9 g / cm ³ Polybutene: average molecular weight 550 Modified polypropylene: Mitsubishi Polypro 6500J 100
Parts by weight, 1 part by weight of maleic anhydride and 0.15 parts by weight of 2,5-dimethyl-2,5-di (t-butylperoxy) hexyne-3, and melt-kneaded at 210 ° C. in a 50 mmφ extruder. Then, pelletization was performed to obtain a modified polypropylene. The amount of maleic anhydride grafted on the modified polypropylene was 0.35% by weight. EVOH resin (ethylene-vinyl alcohol copolymer): manufactured by Nippon Synthetic Chemical Industry Co., Ltd., trade name; Soarnol, ET3803, ethylene content; 38 mol%, M
FR: 4.0 g / 10 minutes (230 ° C)

Example 2 The layer ratio of the multilayer film in Example 1 was 3: 1: 2 :.
It carried out similarly except having set it to 1: 3. The results are shown in Table 6.

Example 3 The same procedure as in Example 1 was carried out except that the water-cooled inflation molding was used as the raw material molding. The results are shown in Table 6. In addition, the original fabric forming condition is a die diameter of 75 mm.
φ, die temperature 250 ° C., blow-up ratio 1.8, take-up speed 10 m / min, folding width 210 mm, thickness 3
A 0 μm film was molded.

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. The same procedure as in Example 1 was carried out except that this recycled material was used for the adhesive layer. The results are shown in Table 6. This shows that the performance is excellent even if the loss is collected and recycled.

Example 5 Same as Example 1 except that the raw materials used for the inner and outer layers and the adhesive layer were the raw materials shown in Table 3. The results are shown in Table 6.

[0048]

[Table 3]

Linear low density polyethylene: Mitsubishi Kasei Co., Ltd.
Made, Mitsubishi Polyech, UF340, MFR; 2.0g / 1
0 minutes (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) hexyne-3 was used in an amount of 19 mm in a 50 mmφ extruder using
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 The procedure of Example 1 was repeated, except that the modified resin shown in Table 4 was used as the raw material for the adhesive layer. The results are shown in Table 6.

[0051]

[Table 4] Modified Polypropylene: Mitsubishi Polypro, 6500J 80
Parts by weight, trade name; Tuffmer A4085 (manufactured by Mitsui Petrochemical Industry Co., Ltd.), MFR 3.6 g / 10 minutes (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 Same as Example 1 except that the modified resin shown in Table 5 was used as the raw material for the adhesive layer. The results are shown in Table 6.

[0053]

[Table 5]

Modified polypropylene: Mitsubishi Polypro 650
100 parts by weight of 0J, 1 part by weight of maleic anhydride, 2,
0.15 parts by weight of 5-dimethyl-2,5-di (t-butylperoxy) hexyne-3 was melt-kneaded at 210 ° C. in a 50 mmφ extruder and pelletized to obtain a modified polypropylene. . The amount of maleic anhydride grafted on the modified polypropylene was 0.35% by weight.

Example 8 Instead of the composition shown in Table 2 used as the inner and outer layers in Example 1, polypropylene / polybutene = 100 /
A film was formed in the same manner except that 20 (parts by weight) of the composition was used. However, the same polypropylene and polybutene as those used in Example 1 were used. The results are shown in Table 6
Shown in.

Comparative Examples 1 to 4 The same procedure as in Example 1 was carried out except that the film thickness, the film layer ratio and the draw ratio shown in Table 6 were used. The results are shown in Table 6.

Comparative Example 5 A multilayer film was crushed in Example 4 to obtain a recycled raw material. A laminated film was produced in the same manner as in Example 4 except that the recycled material was used as an adhesive layer and the specific energy during coextrusion was 0.2 kw · hr / kg. The results are shown in Table 6.

[0058]

[Table 6]

[0059]

The pressure-sensitive adhesive laminated film of the present invention is excellent in cuttability, transparency, interlayer adhesion, heat resistance, barrier property, non-heat shrinkability and food safety. Further, in the present invention, the use of EVOH resin is excellent in productivity as shown below.

Trim loss caused by the need to slit and remove thick portions on both ends of the film through the process of longitudinal uniaxial stretching, and loss of defective products caused by deviating from specifications such as thickness. Whether or not it can be collected and recycled has a great impact on productivity, and it also has a large impact on costs.
That is, it has been said that it is very difficult to carry out the recycling of a multilayer transparent film, especially because the decrease in transparency is a problem. However, according to the present invention, a trim loss consisting of a mixture of a polyolefin, an EVOH resin and an acid-modified polyolefin can be recovered and utilized, and a film having excellent performance such as transparency can be obtained.

Originally, it is necessary to separately set up a recovery layer using a recycled material, but by using a recycled material between the inner and outer layers and the central layer according to the present invention, the adhesive layer also serves as a recovery layer. Become. This has the effect of simplifying the layer structure and reducing the number of extruders required for coextrusion molding.
Further, although plastic films are generally incinerated as a waste treatment after use, the films of the present invention generate harmful gases such as NO _x and hydrogen chloride, which are now problems as gases generated during combustion. Because it does not, it has excellent environmental resistance.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location B29L 9:00 4F

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.
Adhesiveness obtained by co-extrusion molding a laminated film provided with an adhesive layer formed from a resin composition containing 40 parts by weight to 40 parts by weight, and then stretching the film at a draw ratio of 2 to 6 in the film taking direction. A laminated film having an overall thickness of 40 μm or less, and an ethylene-vinyl alcohol copolymer resin layer having a thickness of 10 to 10% of 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