JPS5933308B2 - Packaging material with good adhesion - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a packaging material with good adhesion, especially a packaging material with excellent packaging properties for obtaining a package in which a single item or an aggregate of articles packaged once housed in a box or the like is tightly packaged. The purpose of the present invention is to provide a packaging material having the following properties.

Furthermore, the present invention provides adhesive packaging that has excellent low-temperature thermal adhesion properties, sliding properties in a wide temperature range, hot plate releasability, etc., which are required when packaging articles using an automatic packaging machine, and has excellent transparency. Concerning packaging materials for obtaining bodies. In recent years, sophisticated demands have been placed on the exteriors of foods, tobacco, industrial goods, daily necessities, etc.

For example, in food packaging, in addition to the characteristics of the exterior material such as moisture resistance, aroma retention, insect repellency, and oxygen barrier properties, sealed packaging also prevents tearing, improves the exterior, insufficient sealing of thermally bonded parts during packaging, insufficient adhesive strength, etc. Problems caused by poor airtightness from folded parts of packaging materials due to chicks are becoming more and more important. Furthermore, the odor of packaging materials is also a hygiene problem, and efforts are being made in the industry to reduce residual solvents. On the other hand, as automatic packaging machines have become increasingly faster and more efficient, the following characteristics are required for use in automatic packaging machines. In other words, in addition to low-temperature thermal adhesion properties, there are also important factors such as sliding properties between the packaging material phase and the metal guide of the automatic packaging machine, separability and sliding properties between the packaging material and the hot plate, and sliding properties between the packaging material and the automatic packaging machine. These include the ability to prevent damage caused by movement, and the ability to automatically feed packaging material thorns to automatic packaging machines. However, this alone cannot be said to be a complete close-tight packaging, and a gap is created between the packaged item and the packaging film. For this reason, some external force may catch on the sagging portion of the film and cause it to tear, making it one step more effective in enhancing the appearance. Packaging materials with heat-sealing properties include a coating film manufactured by dissolving a low-melting point substance in an organic solvent and coating it on a base film, and a coating film produced by laminating a low-melting point polymer on a base film and applying it to the heat-sealing surface. A laminated film in which the laminated surface of a low-melting point polymer is facing upward, or a single film in which a low molecular weight thermoplastic resin or the like is mixed with polypropylene or the like has been proposed.

However, the film obtained by the coating method has a weak sealing strength at high temperatures and is not only unsuitable for the sealed package of the present invention, but also tends to cause the heat-sealed portion to separate or move (slip) due to the shrinkage stress during the heat-shrinking treatment. This not only impairs tight packaging but also prevents a perfect package. This means that the cohesive force of the sealing polymer is weak due to the use of a relatively low molecular weight polymer that can be dissolved in a solvent.
Another disadvantage is that it is difficult to completely eliminate residual solvent on the coating surface. A film obtained by mixing a low melting point polymer with polypropylene or the like has poor low-temperature sealing properties and may have poor transparency. Furthermore, since the film is flexible, its stiffness and rigidity are low, and automatic feeding becomes unstable, making it difficult to continuously wrap the film using an automatic packaging machine. Furthermore, although films mixed with low-molecular-weight thermoplastic resins exhibit sealing strength even at low temperatures, they have the disadvantage that their strength decreases as they are heated, making it difficult to obtain packaging with excellent sealing. . This is because the film is at a high temperature immediately after heat sealing, so the sealing strength in this state is weak, making it difficult to seal tightly and to package tightly. Attempts have also been made to laminate a low melting point polymer onto a base film, but as with the case of mixing low melting point polymers, in many cases when sequential biaxial stretching is performed, the opening is fuses to the wall. For this reason, cold stretching is practically necessary, and a transparent film cannot be obtained under such conditions. For example, Tokuko Sho 41-4338
As seen in the publication, stretching in a low-temperature, high-stress field produces a large number of boards inside the film, resulting in a film with pearl-like luster. Another method is to stretch the base film with heated rolls, laminate a low melting point polymer on one or both sides, and then stretch it again with a tenter. However, in neither case has a material phase that can be used for complete tight packaging, which is the first objective of the present invention, been found. The packaging material system of the present invention with good adhesion has the feature that it can be produced by a sequential biaxial stretching method with high productivity and high thickness accuracy. In response to these demands, we have arrived at the present invention as a result of intensive research in order to provide a sealed package on the market.

That is, in the present invention, a film substantially formed from a copolymer of propylene and an α-olefin having 4 to 10 carbon atoms in which the copolymerization ratio of propylene is 70 to 95% by weight is mainly composed of a polypropylene copolymer. It is adhered as a surface layer on one or both sides of the base film as a component, and the thickness of the laminated film is 5 to 200μ, and the thickness of each surface layer is 0.
．． 2 to 10 microns, the total thickness of the surface layer accounts for 0.5 to 50% of the total thickness of the packaging material, and the adhesive laminated packaging material has a satisfactory shrinkage property. The polypropylene polymer forming the base film layer is a propylene-based polymer having a melting point of 140°C or higher, preferably 150°C or higher, and has an isotactic index of 85 (weight), for example.
% or more of isotactic polypropylene, an ethylene/propylene copolymer with an ethylene content of 7% (by weight) or less, a copolymer of propylene with a propylene content of 90% (by weight) or more and an α-olefin having 4 to 6 carbon atoms. The main component is a polymer, or a mixture of these polymers.

The polypropylene polymer preferably has an intrinsic viscosity (135° C. tetralin solution) of 1.6 to 3.0 d1/9. If the intrinsic viscosity is less than 1.6 d1/9, it is difficult to obtain a transparent packaging material, and if it exceeds 3.0 dj/J, the extrudability decreases, making it particularly difficult to obtain a packaging material for the exterior of a package suitable for the present invention. This results in a packaging material that has a poor appearance and reduces the internal product value. In the present invention, a low molecular weight thermoplastic resin may be blended into the base film, but the low molecular weight thermoplastic resin used here forms a mixture with good miscibility with the polypropylene polymer mixed together, and softens the base film. point (measured by ASTM-D36-26) is 70°C ~
150°C, is thermally stable above 150°C, and preferably has a melt viscosity of about 20,000 centipoise or less at 200°C.

8. Miscibility means that no layer separation occurs when polypropylene and the above-mentioned low molecular weight thermoplastic resin are mixed. Also, "thermally stable" means that there is no permanent change in the properties of the resin even after heating for one hour at a given temperature in the presence of air. Additionally, the melt viscosity was measured using a Bruckfield viscometer heated to the indicated elevated temperature according to ASTM test method Dl 824-66. Low molecular weight thermoplastic resins include natural and synthetic waxes, hydrocarbon resins, rosin, dammar,
These include phenolic resins, chlorinated aliphatic hydrocarbon waxes, and chlorinated polynuclear aromatic hydrocarbons. Natural waxes include wood wax, beeswax, spermaceti wax, etc., and synthetic waxes include those made by thermal cracking of high molecular weight polymers, or those made by known polymerization methods starting from monomers such as ethylene and propylene. means a synthetic wax etc. made of a low molecular weight polymer. "Hydrocarbon resin" means a hydrocarbon polymer derived from coke oven gas, coal tar fractions, cracked and deep-cracked petroleum raw materials, essentially pure hydrocarbon stock or turpentine; Typical hydrocarbon resins include, for example, coumaron-indene resin,
There are petroleum resins, styrene resins, cyclopentazine resins, terpene resins, etc.

These resins are described in Kirk Osma's Encyclopedia of Chemical Technology, 2nd edition, Volume 11, 2.
42-255 (1966). 8 "Coumaron-indene resin" refers to hydrocarbon resins recovered from coke oven gas or obtained by polymerization of resin formations present in coal tar distillates, phenol-modified coumaron-indene resins or derivatives thereof. good,
These resins are described in the above literature, 2nd edition, Vol. 11, 243-247.
It is written on the page.

``Petroleum oil 1'' refers to a hydrocarbon resin obtained by catalytic polymerization of deeply decomposed petroleum base phases, and these petroleum base phases generally include styrene, methylstyrene, vinyltoluene, indene, methylindene, butadiene, Contains a mixture of resin formers such as isoprene, piperylene, and pentylene.

This resin is described in the above-mentioned document, 2nd edition, volume 11, pages 248-250. The term ``8-styrene polymer'' refers to a low molecular weight homopolymer of styrene, or a copolymer containing styrene and, for example, α-methylstyrene, vinyltoluene, butadiene, or the like.

"Cyclopentadiene resin" refers to cyclopentadiene homopolymers and copolymers derived from coal tar fractions or separated petroleum gas.

These resins are produced by holding cyclopentadiene-containing bases at elevated temperatures for considerable periods of time. Depending on the temperature maintained, either dimers, trimers or high polymers are obtained. These resins are described in the above literature, 2nd edition, Volume 11, 25.
It is described on pages 0-251. The term "terpene resin" refers to polymers of terpenes, which are hydrocarbons of the general formula C, OH, 6, present in most essential oils and plant oleoresins, and phenol-modified terpene resins.

Suitable terpenes include, for example, α-pinene, β-pinene, dibenzene, limonene, myrcene, bornylene, gamphene and similar terpenes. This resin is described in the above-mentioned document, 2nd edition, volume 11, pages 252-254. "Rosin" refers to resinous substances naturally occurring in pine tree oleoresins and rosin esters, modified rosins such as fractionated, hydrogenated, dehydrogenated or the like.

These substances are described in the above-mentioned literature, Vol. 17, pp. 475-505. Danmaru refers to a colorless to yellow substance or its analogues that naturally exist in plants of the Futabaraceae, Orchidaceae, etc. This substance is published by Kyoritsu Shuppansha, Kagaku Daijiten 7, Vol. 5, page 776. (published in 1962).

6 Phenol resin 1 refers to a reaction product of phenols and aldehydes.

In addition to phenol itself, cresol, xylenol, P
-Ter,t-butylphenol, P-phenylphenol or the like are mentioned as phenolic components, with formaldehyde being the most common aldehyde,
Examples of aldehydes include acetaldehyde and furfuraldehyde. These resins are described in the above-mentioned Encyclopedia, Vol. 15, pp. 176-207. “Chlorinated aliphatic hydrocarbon wax refers to something like chlorinated paraffin wax, which is usually called 6-chlorinated wax, and a typical wax contains about 30 to 70% chlorine by weight.
contains.

“Chlorinated polynuclear aromatic hydrocarbon 1” refers to a chlorinated hydrocarbon having two or more aromatic rings, such as two or more chlorinated biphenyl, terphenyl, etc., or a mixture thereof.

Typical ones contain about 30-70% chlorine by weight. The base film layer of the present invention may further contain other polymers in an amount that does not deteriorate its properties, and the packaging material has improved automatic packaging properties by containing an antistatic agent, a lubricant, an antilocking agent, etc. You can get thorns.

In order to obtain a sealed package, the film is attracted by static electricity in the packaging material supply section of an automatic packaging machine, wrapped around the blade of a cutter, or pulled by electrostatic attraction to a guide plate, which causes the film to become stuck to the packaging material. It must be avoided that the supply does not reach the packaged item in a constant and direct manner.

Regarding this point, the present inventors discovered the following new fact. That is, the phenomenon of static electricity generated by automatic packaging machines can be significantly improved by incorporating an antistatic agent into the base film layer of the film. In particular, there is an acceleration phenomenon when a low molecular weight thermoplastic resin is mixed, and by acceleration, a more remarkable effect is exhibited and the film supplyability is improved. In the present invention, the copolymerization ratio of propylene is 70 to 70 as a surface layer on at least one side of the base film layer.
95% by weight of propylene and α with 4 to 10 carbon atoms
- A film substantially formed from a copolymer with an olefin is adhered.

The polymer constituting the surface layer has a propylene copolymerization ratio of 7.
Propylene with 0-95% polymerization and 4-10 carbon atoms
The α-olefins include ethylene, propylene, benzene, hexane, 4-methylbenzene-1, octene,
Examples include decene, but are not limited to these. Suitably, the melting index of this copolymer is between 0.5 and 159/10%. In such a copolymer, if the propylene content is less than 70% by weight, the transparency will be poor and the coefficient of friction at high temperatures will be high, resulting in scratches and wrinkles on the film or sheet due to poor rubbing during heat sealing. Sealed packages are difficult to obtain using packaging machines. Also,
When the sequential biaxial stretching is carried out, adhesion and fusion to the heated stretching rolls tend to occur, making it impossible to commercially obtain a packaging material consisting of a film or sheet that is smooth, scratch-free, and has an excellent appearance. Furthermore, if the propylene content is 95% (by weight) or more, the heat sealability will deteriorate, making it particularly difficult to heat seal at low temperatures and at high speeds, and the heat sealing temperature must be increased, causing the film in the heat sealing part to deteriorate. Beautiful packaging cannot be obtained due to heat damage. The above copolymer 100
In the present invention, it is preferable to mix 0.01 to 0.15 parts by weight of silicone oil with respect to parts by weight.

Silicone oils that can be used in the present invention include polydimethylsiloxane, polymethylphenylsiloxane, olefin-modified silicone, polyether-modified silicone modified with polyethylene glycol or polypropylene glycol, olefin/polyether-modified silicone, epoxy-modified silicone, and amino-modified silicone. , is a silicone oil containing modified siloxaquine bonds such as alcohol-modified silicone. Among these silicone oils, olefin-modified silicone, polyether-modified silicone, olefin/polyether-modified silicone, etc. are particularly excellent. The silicone oil improves the coefficient of friction of the film when heated, reduces the sliding resistance that occurs during hot plate sealing in automatic packaging machines, and prevents wrinkles, resulting in a beautiful appearance and high sealing performance. The basis for obtaining a film that maintains the performance of adhesion to the packaged object without sagging can be created. In addition, it is possible to prevent a decrease in gloss due to sliding and obtain a beautiful seal. In the present invention when silicone oil is used in combination, the high temperature friction coefficient is set to 1.0 when performing sliding heat sealing.
It can be reduced to 4 or less. This is an important requirement to achieve the above purpose. The silicone oil preferably has a viscosity of 50 to 10,000 centistokes at room temperature, more preferably a low viscosity of 50 to 300 centistokes. In addition to the silicone oil, ethylene oxide adducts of star oil with a softening point of 70°C to 140°C, oxidized synthetic waxes, higher fatty acid alkyl esters, polyhydric alcohol alkylate ethylene oxide adducts, fatty acid amide, etc. are used in combination. By doing so, it is possible to further increase the effectiveness. It is desirable to use a mixture of these in an amount of 1 to 300 parts, particularly 50 to 300 parts, per 100 parts of silicone oil. By using this additive in combination with silicone oil, it is possible to prevent stick slip at temperatures between room temperature and 100°C or less, which tends to occur when silicone oil is used alone, and to prevent interference with various metal guide plates of automatic packaging machines. This makes it possible to prevent packaging defects from occurring.
Furthermore, it improves the cleanliness under high temperature and pressure, which is extremely important for obtaining the sealed package of the present invention. This specific value is a high temperature friction coefficient of 1.4 or less, preferably 1.0 or less. The silicone oil and the above-mentioned additives are not only good, but also tend to reduce the heat sealability of the film or sheet, and also tend to reduce the transparency. Therefore, simply adding it tends to reduce the low-temperature heat-sealing properties, resulting in heat-sealing at a slightly higher temperature. The mixing range of the present invention indicates a preferable mixing amount that satisfies this point. Generally, when heat sealing is performed at high speed and high temperature using an automatic packaging machine, the surface of the film or sheet is damaged and thermal shrinkage occurs, making it impossible to obtain a smooth sealing surface.

That is, biaxially stretched films such as polypropylene have high crystallinity and melting point, and cannot achieve uniform shrinkage like polyvinyl chloride and the like. In the case of biaxially stretched polypropylene film, the portion that comes into contact with the hot plate contracts, and depending on the contact conditions, a sealing surface that is extremely uneven can be obtained. This phenomenon causes a partial seal failure due to the occurrence of unevenness in the tightly sealed package which is the object of the present invention, and a highly airtight package cannot be expected. In order to obtain these close-fitting and sealed packages, it is of course possible to perform low-temperature heat sealing as described above.
It is necessary that the sealing strength of the heat-sealed part is strong even in the heated state, and that the coefficient of friction in the heated state is low. Specifically, the heat seal strength at 120°C is 409/(177!
The above is desirable. The heat-sealed package is then heat-shrinked using a heat-shrinker such as a heat-shrink tunnel.
If the heat-sealing strength decreases after heat shrinkage, the seal portion may come off or shift due to shrinkage stress, resulting in loss of adhesion and, of course, poor sealing performance. The heat-sealing strength retention rate of the heat-shrinkable packaging material phase of the present invention is 60% or more, preferably 80% or more. Further, it is desirable that the friction coefficient at high temperature is, for example, 1.4 or less at 120°C. Furthermore, in order to heat-shrink the article after packaging to obtain a completely adhesive package, the present invention must have not only the above-mentioned properties but also the following shrinkage properties. By having SF (SFm and SFC of 3.5% or more), it is possible to eliminate the gap that occurs between the packaged object and the packaging material during automatic packaging over a wide heat shrinkage temperature range. .

Further, by satisfying 1St-Sml≧1.5%, it is possible to avoid wrinkles remaining at the corners of the package when the article is packaged and then heat-treated to form a shrink-tight package.

The state of occurrence of wrinkles is shown in FIG. Also, 1St-Sml
Figure 2 shows the value of and the state of wrinkles. Ichiriki, (SFt-S
If t) and (SFm-Sm) are not each 1.15% or more, relatively large wrinkles will remain in the form of folds when the article is packaged and then heat-shrinked.

If wrinkles or folds remain, it will not only give a poor appearance but also cause damage due to snagging during transportation or handling. The heating method of the heat shrinker (heat shrink oven) includes infrared heating, electric heating, flame heating, hot air heating, and hot water heating.

In the manufacturing method of the packaging material system of the present invention, layers A and B can be bonded together using an adhesive, but layers A and B are extruded from separate extruders and a composite flow is produced in a molten state. A co-extrusion method of extrusion molding, a method of separately melt-extruding and laminating before cooling and solidifying, or a method of gluing one film or sheet in a melt-extruded state to a partially drawn or stretched film or sheet that has been cooled and solidified. Alternatively, a composite film or sheet can be obtained by a method of continuously stretching the film or the like.

These methods may be used to form either a flat film or an annular film, but effective sealant ribs can be provided by biaxially stretching and retaining heat shrinkability. A feature of the packaging material ribs of the present invention is that they can be manufactured by a sequential biaxial stretching method in which heated rolls are used during longitudinal stretching, and of course simultaneous stretching is even easier. Sequential biaxial stretching can obtain a strong composite layer bonding force between layers to obtain a packaging material size with good heat sealing strength, and the close contact packaging of the present invention can be used because it is possible to economically produce a laminate. The significance of the material is extremely high. Suitable conditions for stretching will be described below.

3 in each of the longitudinal and transverse directions for biaxial stretching.
, stretched 5 to 10 times.

The stretching temperature is usually 100 to 160°C in the case of roll stretching, and 140 to 165°C in the case of tenter stretching. In the present invention, when sequential biaxial stretching is performed, the stretching is performed 3.5 to 10 times, preferably 3.8 to 75 times, in the machine direction, and 4 to 12 times, preferably 6 to 9 times, in the transverse direction. In the case of biaxial stretching, it is carried out at 140 to 165°C. Sequential 2
In the case of axial stretching, the first stage is 100°C to 160°C, preferably 110°C to 130°C, and the second stage is 140°C to 160°C.
5°C, preferably 145°C to 160°C. Although it is not necessary to carry out heat treatment after stretching, it may be carried out within a range that does not cause loss of the heat shrinkage characteristics due to changes in the film over time, reduction in the winding tightness of the product roll, etc. -Generally from 50℃
It is 3 to 60 seconds at 135°C. The resulting stretched film may be subjected to metal vapor deposition over the entire surface or a portion thereof, if desired.

For example, letters, decorations, etc. can be deposited or left undeposited, and non-deposited parts such as a window can be left. Further, there are cases where a metal vapor deposition layer is not formed on a portion that is to be heat-sealed later. When forming a metal vapor deposited layer on a portion to be heat sealed, it is desirable that the metal vapor deposited layer be an inner layer (on the article side). The metal to be vapor-deposited is usually aluminum, but gold,
Metals such as silver, nickel, and cobalt are also used.

To vapor-deposit metal onto a film, the metal is vacuum-deposited using a conventional method. However, prior to vapor-deposition, the film may be subjected to surface activation treatments such as flame treatment, chemical treatment, corona treatment, or ionizing radiation treatment. Coating with an anchor agent to improve the adhesion between the metal and the vapor-deposited metal is preferable in order to improve adhesion, prevent discoloration of printing ink, and improve heat resistance. It is also possible to print with a printing ink prior to vapor deposition.
As the printing ink, either face type or dyed type ink can be used arbitrarily. The thickness of the metal to be deposited will of course vary depending on the purpose, but a thickness of 1008 to 2000 λ is appropriate for suppressing moisture permeability. Examples of anchor agents used in the anchor coating treatment prior to the metal vapor deposition process include thermosetting types such as polyisocyanate, urethane, and melamine, polyethyleneimine, titanium, acrylic ester, ethylene vinyl acetate, and chloride. Various types such as vinylidene type, chlorinated polyolefin type, and linear copolymerized polyester type can be used alone or in combination. It is optional to further provide a conventional resin protective layer on the outer surface of the metal deposited layer.
In order to obtain a close-fitting, sealed package, when the packaged items are immediately tightly sealed and sealed using the packaging material bar of the present invention, or when the packaged items are contracted in advance into a box by a predetermined amount and then the box is In some cases, a large number of such materials may be hermetically packaged using the laminated packaging material layer of the present invention.

In either case, it is sufficient that the adhesive is thermally melted and bonded in close contact with the packaged item. The thickness range of the laminated packaging material phase of the present invention is determined depending on the specific use when forming it as a close-fitting packaging, but is in the range of 5 to 200 microns.

A commonly used range is 15-60μ. Among the packaging material phases of the present invention, the thickness of the surface layer is 0.0% of the total thickness of the packaging material.
It ranges from 2 to 50%. After an article is hermetically packaged using the packaging material of the present invention using an automatic packaging machine, it is passed through a heat shrinker.

Conditions such as temperature and time can be appropriately selected within a range that does not damage the packaged items. In the case of a close-contact package, the thickness of each surface layer is within the range of the above thickness ratio. 2~
10μ, especially O. The thickness is preferably about 2 to 3 μm. Before describing embodiments of the present invention, a measurement method will be described.

1) Haze: Measured using a "Haze Tester" manufactured by Toyo Seiki Co., Ltd. according to JIS-K-6714.

2) Automatic feeding ability: The packaging material was automatically fed and evaluated using a W-37 model packaging machine manufactured by Tokyo Automatic Machinery Co., Ltd.

○ No problem △ Occasionally unable to supply

ONo problem△Conspicuous wrinkles×Many wrinkles, no commercial value 4) Heat sealing strength: After heat sealing with a tilted heat sealer manufactured by Toyo Seiki Co., Ltd. under a pressure of 1k9/~ x 1.0 seconds, its strength was evaluated. Peel strength was measured at a speed of 200 mm/min.

5) Adhesive packaging property: After packaging with the automatic packaging machine used in 2) above, it is passed through a heating oven and heated. Appearance of packaged product after shrinking.

◎ It was completely adhered, there were no wrinkles, and it was possible to wrap it under tension.

○ Although it is in close contact, there are some wrinkles.

I was able to wrap it under tension. △ There are parts that are in close contact with each other and parts that are not in close contact with each other, and wrinkles are present.

X There are many wrinkles.

6) Free thermal shrinkage rate SF: film width 15, length 30
0m77! The test piece was cut into pieces, marked with a length of 200 mm between the gauge marks, and heat-shrinked at 120°C with the test piece in a free state.
It was calculated using the following formula from the lengths LF and LF'' before and after contraction.

7) Heat shrinkage rate under restraint S: 110mm x 70m77! Fix the film to a pair of parallel sides of a rectangular frame, leave the other pair of parallel sides unfixed, and heat-shrink it at 120°C.
It was calculated using the following formula from the lengths L and L'' before and after contraction.

Example 1 Isotactic polypropylene 1 with an intrinsic viscosity of 1.8 dl/9 (using a tetralin solution at 135°C) as the base layer 1
00 parts by weight, the alkylamine ethylene oxide adduct was added to 0.00 parts by weight. 8 parts by weight of glycerin fatty acid ester. The composition was a mixture of 3 parts (by weight).

On the other hand, as the surface layer 2, the propylene content is 81 (weight) (:
! )) to 100 parts by weight of propylene/butene-1 copolymer with glycerin fatty acid ester O. 3 parts by weight, calcium carbonate O. A composition containing 8 parts by weight was used. These compositions were melt-extruded using two extruders to obtain 2/1/2 three-layer unstretched films. The unstretched film had a thickness of 950μ and was stretched 4 times in the machine direction at 135°C, subsequently stretched 9.5 times in the cross direction at 155°C, and then stretched at 85°C.
After being subjected to tension heat treatment (5 seconds) at ℃, the film was passed through a temperature-controlled oven at 85℃ while giving a relaxation rate of 4%, and then cooled by forcibly blowing air at 40℃ to obtain a biaxially stretched film. Ta. This film was corona discharge treated to a surface tension of 43 dynes/CTIL (1), and the corona-treated surface was coated with an isocyanate adhesive, and aluminum was further vapor-deposited (however, the areas scheduled for heat sealing were not vapor-deposited with metal). (H) and were prepared and packaged into drug cases using an overlap machine. After packaging, the heated air shown in Table 1 was blown from above and below and passed through an oven for the time shown in Table 1 to shrink the outer film and obtain a tight package. Example 2 Base layer 1 was made of 90% by weight of isotactic polypropylene with an inherent viscosity of 2.0 dl/9 (using a tetralin solution at 135°C) and a petroleum resin (manufactured by Arakawa Forestry Co., Ltd., Alcon P-
115) 100 parts by weight of a mixed composition consisting of 10% by weight, 1 part by weight of alkylamine ethylene oxide adduct.
．． O parts by weight, glycerin stearate ester.
The composition was a mixture of 5 parts by weight.

On the other hand, the surface layer 2 is made of propylene-hexene-1 polymer (
Hexene-L content: 15% by weight) and 100 parts by weight of glycerin fatty acid ester O. 4 parts by weight, 0.5 parts by weight of hydroxystearamide (Diaamide KH, manufactured by Nippon Kasei),
A composition containing 0.1 part by weight of polyethylene wax (molecular weight 2000) was used.

Melt extrusion 2 of the compositions of the first and second layers from two extruders
A three-layer unstretched film of /1/2 was obtained.

The unstretched film has a thickness of 1000μ and is heated at 130°C.
Stretched 5 times in the machine direction, then stretched 160 times in the transverse direction
It was stretched 8.0 times at 100°C, then passed through a temperature-controlled oven for 8 seconds while giving a relaxation rate of 4% at 100°C, and cooled by forcibly blowing air at 20°C. An axially stretched film was obtained. This film has a surface tension of 40 dynes/
After corona discharge treatment was applied to CTfL and printing was performed on the surface (printing ink: NPA manufactured by Toyo Ink Co., Ltd. was used), a medicine case was packaged using an overlap machine. After packaging, heated air at 120° C. was blown from above and below and passed through an oven for 10 seconds to shrink the outer film to obtain a tight package. Comparative Example 1 Stretched in the same manner as in Example 2, then at 155°C
The sample was subjected to 5% mild heat fixation, and then treated in the same manner as in Example 2, and packaged in the same manner.

Comparative Example 2 A composite biaxially stretched film was prepared in the same manner as in Comparative Example 1, except that a propylene/ethylene copolymer (M2.59/10 min) with an ethylene content of 3.4% by weight was used as the surface layer.

The obtained film was tightly wrapped using an automatic packaging machine in the same manner as in Example 2, and passed through a shrink oven under the same conditions. Comparative example 3 Isotactic polypropylene (intrinsic viscosity 2.0d
1/9) The same content as the additive formulation of the base layer of Example 2 was mixed into a composition of 60% by weight and 140% by weight of polybutene, and the mixture was melt-extruded to form a 1000μ thick end-stretched film. The resulting film was stretched 5.0 times in the machine direction at 110°C, then 8.0 times in the transverse direction at 145°C, and heat-set under the same conditions as Comparative Example 1 to form a biaxially stretched film with a thickness of 25μ. Obtained.

The biaxially stretched film was automatically packaged in the same manner as in Example 2 and passed through a heat shrink oven. In the packaging material of the present invention, the base value was low, the packaged items looked beautiful, there were few wrinkles in the heat-sealed portion of the package, and the package was packaged extremely tightly after passing through the shrink oven. The extent of this can be judged from the length of the residual slack. In Comparative Example 2, since automatic feeding was not possible, packaging was performed intermittently and then shrink-wrapped. However, tight packaging was difficult. Next, Table 2 shows the changes in the packaging material after close-contact packaging.

In addition, in Comparative Examples 1 to 3, the shrinkage conditions were set to 150° C. for 0.5 minutes since tight packaging did not occur even at 1300° C. for 0.5 minutes. Example 3 After printing in Example 2, the film was coated with an isocyanate adhesive and a linear copolymerized polyester adhesive.
After coating with an anchoring agent mixed in a 5/5 ratio (by weight), metal vapor deposition was performed (a window was formed so that the inside could be partially seen, and no metal vapor deposition was applied to the heat-sealed portions).

A power case was overwrapped with this film, and then hot air at a temperature of 200° C. was blown at a speed of 5 m/sec for 4 seconds. The obtained package was an excellent adhesive package, the ink layer and the metal vapor deposited layer had good gloss and no color. Example 4 In the film () of Example 1, coated l
An acrylic acid adhesive (A) and a highly branched ethylene vinyl acetate copolymer adhesive (B) an isocyanate adhesive were mixed in the following proportions. and gloss were examined.

The results are as follows, all of which are better than those without any coaching. An unstretched film with a thickness of 100.0μ was obtained using the same composition and method as Example 5, Comparative Example 4, and Example 1, and the unstretched film was sequentially processed in the longitudinal and transverse directions at the temperature and magnification shown in the table below. A film was obtained by stretching heat treatment, followed by relaxation and cooling in the same manner, and was packaged into a drug case using the same overlap machine.

The results are shown below. Adhesive packaging properties are determined by wrapping the package at 120°C
This is the data after passing through the oven for 1 minute. A, B,
F, G, K, L, and M are comparative examples.

Example 6, Comparative Example 5 Using the same composition and method as in Example 1, the thickness of the surface layer was made lignified (the overall thickness was the same), and a packaging test was conducted in the same manner as film formation and stretching.

The results are shown below. Example 7 In Example 1, a propylene-butene-hexene copolymer (78:17:5) was used as the polymer constituting the surface layer, and the tension heat treatment temperature and time of the film were as follows.

Claims (1)

[Scope of Claims] 1. A film substantially formed from a copolymer of propylene and an α-olefin having 4 to 10 carbon atoms in which the copolymerization ratio of propylene is 70 to 95% by weight is a polypropylene polymer. It is adhered as a surface layer to one or both sides of a base film mainly composed of
~200μ, and the individual thickness of the surface layer is 0.2-10
μ, and the total thickness of the surface layer is 0 of the total thickness of the packaging material.
．． 5 to 50%, and the shrinkage property is SFm≧3.5
% Formula 1 SFt≧3.5% Formula 2 1St-Sm1≧1.5% Formula 3 SFt-St≧1.15% Formula 4 SFm-Sm≧1.15% Formula 5 SF: Free thermal shrinkage rate at 120°C S: Heat shrinkage rate under restraint at 120°C m: An auxiliary symbol indicating the longitudinal direction t: An adhesive laminated packaging material that satisfies the auxiliary symbol indicating the lateral direction. 2. A metal-deposited adhesive laminated packaging material, wherein a metal vapor-deposited layer is formed on a portion of the surface layer of the adhesive laminated packaging material according to claim 1. 3. A composition in which the surface layer of the adhesive laminated packaging material according to claim 1 or 2 contains 0.01 to 0.15 parts by weight of silicone oil based on 100 parts by weight of the polymer constituting it. Adhesive laminated packaging material made of materials. 4. The base film of the adhesive laminated packaging material according to claim 1, 2, or 3 comprises 80 to 98% by weight of a polypropylene polymer and 20 to 98% by weight of a low molecular weight thermoplastic resin.
An adhesive laminated packaging material which is a film containing 2% by weight. 5 Claims 1, 2, 3, or 4
The adhesive laminated packaging material according to item 1, wherein the base film of the adhesive laminated packaging material is a film containing an antistatic agent in its constituent polymer.