KR101258728B1 - Packaging material - Google Patents

Abstract

[PROBLEMS] The present invention is a polypropylene-based film having excellent packaging suitability for rice balls, sandwiches, and the like, having good transparency and appearance, and having extremely low generation of odors from the film, particularly in the extrusion direction of the resin during film production. The tearing direction of the present invention provides a packaging material having excellent tearing property, which has a high linearity even under a heating environment, and further has a low tearing strength.

[Solution] A non-stretched film comprising at least two layers of a base layer and a surface layer, wherein the packaging material made of a polypropylene film characterized by satisfying the following (1) to (3).

(1) The base layer contains 99 to 99.97% by mass of propylene homopolymer having a melting point of 162 ° C or higher and 0.03 to 1% by mass of phosphate ester metal salt as an organic crystal nucleating agent, and has a thickness of 10 µm or more.

(2) The surface layer is made of a propylene-? Olefin copolymer having a melting point of 155 ° C. or less, and has a thickness of 1 μm or more.

(3) The thickness of the base layer is 50 to 98% of the total thickness of the packaging material.

Tear strength, tear aromaticity, polypropylene, unstretched, copolymerized, nucleating agent

Description

Packing material {PACKAGING MATERIAL}

The present invention relates to a packaging material consisting of a polypropylene film. More specifically, the present invention relates to a packaging material made of a polypropylene film having excellent packaging suitability such as rice balls and sandwiches, good transparency and appearance, and extremely low generation of odors from the film. In particular, the tearing direction of the resin in the extrusion direction (hereinafter referred to as the “longitudinal direction”) during film production has a high linearity even under a heating environment, and also has excellent tearing strength with low tearing strength. The present invention relates to a packaging material having characteristics.

Conventionally, various packaging materials using films made of thermoplastic resins have been proposed. These packaging materials are used in the packaging of food, clothing, industrial parts, and the like, and are used in a wide range of fields as sealed bags by heat sealing (heat sealing) or the like for preserving the contents and protecting them from dust and dust.

When using a packaged product, it is necessary to open the packaging bag, which is usually torn by hand. In this case, it can tear without applying a large force, and if a tearing direction is linear, a packaging bag can be torn without damaging the shape etc. of contents, and can be opened easily.

In order to facilitate opening, it is common to provide a cutting part (notch) for opening. In addition, the film needs to be torn in the same direction as the cutout portion, and the film has a linear tearing direction, and a film having a small tearing strength at that time is required.

As a conventional olefinic film having a tearing direction (tear direction), a stretched film has been proposed by applying stretching in the longitudinal direction (see Patent Document 1).

Moreover, in order to improve tearing direction by unstretched or uniaxial stretching of low magnification, it was proposed to use the film as a film forming the composition which consists of a polypropylene resin and a sorbitol derivative (refer patent document 2).

Furthermore, by blending a heat-sealing film (see Patent Literature 3), a polypropylene resin, polyethylene, and polybutene-1 having a vulnerable property formed by molding a resin mixture of a propylene polymer and a styrene polymer, There exists the casting film (refer patent document 4, 5) of the characteristic which is easy to be made.

However, the stretched film is required for the stretched film, and roll contamination is liable to occur because the roll temperature during stretching is high. When high magnification stretching is performed, thickness nonuniformity and stretching nonuniformity of the film are likely to occur at the time of manufacture, and there is a problem that transparency is lowered.

Moreover, when using the film which formed the composition which consists of a polypropylene resin and a sorbitol derivative, tear direction becomes favorable, but odor arises from the film formed and usage is restrict | limited to food use. In addition, the sorbitol derivative spreads (bleeds) to the surface of the film as time passes after film formation, resulting in a decrease in transparency and causing roll contamination during secondary processing such as slits and printing.

Furthermore, in the case of a film formed by molding a resin mixture of a propylene polymer and a styrene polymer, since the propylene polymer and the styrene polymer do not melt with each other, transparency is poor. In addition, the impact resistance is not sufficient because the strength of the styrene polymer is weak.

In addition, in the case of a cast film having an easy tear property formed by blending a polypropylene resin, polyethylene, and polybutene-1, the tear property of the film is poor, particularly when a rice ball or the like packed in a convenience store or the like is eaten after heating in a microwave oven.

As a result of the above problems, the film has good tearing property in the longitudinal direction, low tearing strength, excellent tearing property, excellent tearing direction under heating environment, and no odor, transparency and appearance. It was difficult to obtain.

[Patent Document 1] Japanese Patent No. 3556460

[Patent Document 2] Japanese Patent Application Laid-Open No. 1-299831

[Patent Document 3] Japanese Patent Application Laid-Open No. 64-56740

[Patent Document 4] Japanese Patent Application Laid-Open No. 2006-117956

[Patent Document 5] Japanese Patent No. 3813263

The present invention has been made to solve the above problems, and is made of a polypropylene film having excellent packaging suitability, particularly having excellent tearing characteristics even in a heating environment, having good transparency and appearance, and extremely low occurrence of odor. It is an object to provide a packaging material.

MEANS TO SOLVE THE PROBLEM As a result of earnestly researching in order to solve the said subject, as a result, by laminating | stacking the base layer which has a specific thickness containing a specific polypropylene resin and an organic nucleating agent, and the surface layer which has a specific thickness which consists of a specific propylene-alphaolefin copolymer, It was confirmed that a packaging material made of a polypropylene-based film having excellent packaging suitability, particularly having excellent tearing characteristics even under a heating environment, having good transparency and appearance, and extremely low generation of odors was obtained.

That is, this invention which solves the said subject includes the following matter as a summary.

[1] A packaging material comprising a polypropylene-based film, wherein the non-stretched film comprising at least two layers of a base layer and a surface layer satisfies the following (1) to (3).

(1) The base layer contains 99 to 99.97 mass% of propylene homopolymer having a melting point of 162 ° C. or higher and 0.03 to 1 mass% of phosphate ester metal salt as an organic crystal nucleating agent, and has a thickness of 10 μm or more.

(2) The surface layer is made of a propylene-? Olefin copolymer having a melting point of 155 ° C. or less, and has a thickness of 1 μm or more.

(3) The thickness of the base layer is 50 to 98% of the total thickness of the packaging material.

[2] The packaging material according to [1], wherein the organic crystal nucleating agent is an ester aluminum phosphate salt.

[3] [1] consisting of adding 0.1 to 4 parts by mass of an antifogging agent to 100 parts by mass of the resin constituting the base layer and the surface layer, and applying a corona discharge treatment to the surface of at least one layer. The packaging material as described in [2].

According to the present invention, a packaging material which is excellent in packing suitability, has excellent tearing characteristics, particularly in a heating environment, has good transparency and appearance, and has a low generation of odors, is obtained.

Moreover, the packaging material which consists of a polypropylene film by which the antifogging property was improved by containing an antifogging agent can be obtained.

Hereinafter, the present invention will be described in more detail, including the most preferred form.

The packaging material according to the present invention is a polypropylene-based film having excellent longitudinal tearing characteristics, and is composed of a base layer containing propylene homopolymer as a main component and a surface layer containing propylene-? Olefin copolymer as a main component.

The base layer comprises 99 to 99.97 mass% of propylene homopolymer having a melting point of 162 ° C. or more and 0.03 to 1 mass% of organic crystal nucleating agent, and has a thickness of 10 μm or more, and the surface layer is made of a propylene-α olefin copolymer having a melting point of 155 ° C. or less. Having a thickness of 1 μm or more is very important for achieving a predetermined effect.

In the packaging material according to the present invention, the propylene homopolymer used for the base layer has a melting point of 162 ° C. or higher, preferably 163 ° C. or higher, and a range of 163 to 170 ° C. particularly measured by a differential scanning calorimeter. desirable. When the polypropylene melting point used for the base layer is less than 162 ° C, the tearing direction (tearing direction) in the heating environment is lowered, and the tear strength at that time is increased.

In addition, the melt mass flow rate (MFR) at 230 ° C. of the propylene homopolymer is preferably in the range of 2 to 50 g / 10 minutes, preferably 4 to 40 g / 10 minutes in view of film forming properties. .

An organic crystal nucleating agent is mix | blended with the base layer which comprises the packaging material by this invention. As the inorganic crystal nucleating agent, the tearing property is not improved, and transparency is lowered.

Moreover, as said organic crystal nucleating agent, since the phosphate ester metal salt, especially the aluminum phosphate ester salt is excellent in tearing property, and generation | occurrence | production of odor is extremely small, it is used preferably in this invention.

On the other hand, sorbitol derivatives such as dibenzylidene sorbitol and dimethylbenzylidene sorbitol, rosin metal chlorides, benzoic acid metal salts, and the like are generally known as organic crystal nucleating agents. It is not preferable because it is easy. Tear property is degraded with rosin metal chloride and benzoic acid salt.

In the present invention, the amount of the organic crystal nucleating agent added is 0.03 to 1 mass% based on 99 to 99.97 mass% of the propylene homopolymer, and preferably 0.1 to 0.5 mass% of the organic crystal nucleating agent is added to 99.5 to 99.9 mass% of the propylene homopolymer. It is preferable, More preferably, the range of 0.12-0.4 mass% of organic crystal nucleating agents with respect to 99.6-99.88 mass% of propylene homopolymers is especially preferable. When the addition amount of the organic crystal nucleating agent is less than 0.03 mass%, the tearing property and the transparency are lowered. Moreover, when the addition amount of the organic crystal nucleating agent exceeds 1 mass%, the improvement of the tearing property reaches a limit and becomes economically disadvantageous. For the surface layer, the presence or absence of the addition of the organic crystal nucleating agent is not particularly limited.

In the present invention, the addition of the nucleating agent exhibits an effect of increasing the tensile modulus of elasticity of the film in addition to the effect of improving the tearing property of the packaging material made of the polypropylene-based film. That is, the tensile modulus of elasticity in the extrusion direction (longitudinal direction) when the film is produced by the addition of the organic crystal nucleating agent exhibits a value exceeding 1000 MPa. Accordingly, in the present invention, the pitch stability is excellent even when the printing layer is formed on a packaging material made of a polypropylene film.

The thickness of the base layer which consists of the above propylene homopolymer as a main component is 10 micrometers or more, Preferably it is 12 micrometers or more, The range of 12-80 micrometers is especially preferable. When the thickness of the base layer is less than 10 µm, the tear direction in the heating environment is lowered, and the tear strength at that time is increased.

The propylene-α-olefin copolymer used for the surface layer means a copolymer of propylene and α-olefin (including ethylene). As the α-olefin, ethylene and an α-olefin having 4 to 10 carbon atoms are preferable, and ethylene, butene, pentene-1, hexene-1, octene-1 and the like are preferably used. The content rate of the propylene unit in a propylene-alpha olefin copolymer is 99.7-85 mass%, Preferably it is 99-90 mass%. In addition, the copolymer composition of the said propylene-alpha olefin copolymer can be measured using the nuclear magnetic resonance apparatus mentioned later.

Among these, as the propylene-? Olefin copolymer, a propylene-ethylene copolymer and a propylene-ethylene-butene copolymer are preferable, and a propylene-? Olefin copolymer having a narrow compositional distribution is more preferable. Particularly preferred propylene-αolefin copolymers have a ratio (Mw / Mn) of 4.5 by weight permeation molecular weight (Mw) and number average molecular weight (Mn) measured by gel permeation chromatography (GPC) prepared by a metalocene catalyst. The following propylene-alpha olefin copolymer is mentioned. These propylene-α olefin copolymers may be used alone, or two or more kinds thereof may be used.

For the propylene-? Olefin copolymer, the melting point measured by the differential scanning calorimeter is preferably 155 ° C. or lower, more preferably 150 ° C. or lower. When melting | fusing point exceeds 155 degreeC, the heat sealing (heat sealing) characteristic at the time of packaging falls, and when it is less than 100 degreeC, the tearing property after heating in a microwave oven etc. falls. Therefore, the melting point of the propylene-? Olefin copolymer is preferably in the range of 100 to 150 ° C, more preferably in the range of 130 to 150 ° C. Melting | fusing point of the said propylene-alpha olefin copolymer can be adjusted by the well-known method of selecting suitably the kind and ratio of the monomer copolymerized at the manufacturing process.

In addition, the MFR at 230 ° C of the propylene-α olefin copolymer is preferably in the range of 2 to 50 g / 10 minutes, preferably 4 to 20 g / 10 minutes, in view of film forming properties. More preferably, the range of 6-15 g / 10min is preferable in order to stabilize the thick film at the time of film forming.

The thickness of the surface layer which consists of the above propylene- alpha olefin copolymer as a main component is 1 micrometer or more, Preferably it is 2 micrometers or more and the range of 2-10 micrometers is especially preferable. When the thickness of the surface layer is less than 1 µm, the heat sealing characteristic is lowered. Moreover, when it exceeds 10 micrometers, tearing property will fall.

The surface layer may be laminated on at least one surface of the base layer directly or via an adhesive layer, and another resin layer may be interposed between the surface layer and the base layer as long as it does not significantly affect the tearing characteristics.

In addition, the packaging material according to the present invention may be provided with an adhesive layer on the base layer surface opposite to the surface layer for the purpose of further improving the heat sealing characteristics. The adhesive layer can be formed, for example, by laminating a propylene-αolefin copolymer having a melting point of 100 ° C or higher, preferably 130 ° C or higher. When providing an adhesive layer, the thickness is 1 micrometer, and the range of 1-10 micrometers is especially preferable. When the thickness of the adhesive layer is less than 1 µm, there is a concern that a sufficient adhesive improvement effect cannot be obtained, and when the thickness of the adhesive layer exceeds 10 µm, the tearing property is lowered, which is not preferable. Although it does not specifically limit about the propylene-alphaolefin copolymer which comprises an adhesive layer, The propylene-alphaolefin copolymer used for the said surface layer can be used preferably.

The total thickness of the packaging material according to the present invention including the base layer, the surface layer and, if necessary, the adhesive layer is not particularly limited as long as it is a total thickness capable of securing the thickness of the base layer and the surface layer, but is generally 12 to 100 μm, preferably Is 18 to 60 µm. It is also essential that the thickness of the base layer is at least 50% and less than 98% of the total thickness of the packaging material. When the thickness of the base layer is less than 50% of the total thickness, the tearing property is lowered, and in particular, the tearing property after heating is lowered. In addition, when the thickness of the base layer exceeds 98% of the total thickness, the heat sealing characteristic is lowered.

Moreover, in the packaging material by this invention, an antifogging agent can be added to a base layer and / or a surface layer as needed. Antifoaming agents generally include known substances called antifogging agents, antistatic agents and surfactants. Examples of the antifogging agents include polyhydric alcohols such as glycerin, polyethylene glycol, pentaerythritol, sorbitol, and polypropylene glycol, and lauric acid and stearic acid. Esters with higher fatty acids such as oleic acid, ethylene oxide adducts of higher aliphatic amines, higher aliphatic alkanolamides, higher alcohol phosphate ester salts, and mixtures thereof. The addition amount of an antifogging agent is 0.1-4 weight part with respect to 100 weight part of said propylene polymers (propylene homopolymer in a base layer, and propylene-alphaolefin copolymer in a surface layer), Preferably it is 0.2-2 weight part. When the added amount of the antifogging agent is less than 0.1 part by weight, the expression effect of the antifogging agent is insignificant. On the other hand, when the antifogging agent is added above 4 parts by weight, the antifogging agent may spread to the surface (bleeding) and the film may be blocked, and the transparency tends to decrease. .

The blending method of the said antifogging agent is not specifically limited, What is necessary is just to employ | adopt a conventionally well-known method, For example, when manufacturing the said propylene polymer, the method of mix | blending an antifog simultaneously and the master batch of another antifog additive ( master batch), and a method of blending the required amount during film formation.

Moreover, as a raw material resin of the packaging material by this invention, you may mix | blend well-known additives, such as an anti blocking agent, antioxidant, a light stabilizer, a lubricating agent, a coloring agent, and an antibacterial agent, as needed.

In the packaging material according to the present invention, other films such as polypropylene, polyethylene, polystyrene, polyamide, polyethylene terephthalate and the like may be laminated and used by a known method such as dry lamination or extrusion lamination. In this case, it is preferable to add a corona discharge treatment to the surface to be laminated in advance.

The packaging material according to the present invention is formed into a film by the non-stretching method. Exemplary methods include extrusion molding using a T die and inflation molding using a cyclic die. In the above molding method, for example, a co-extrusion method according to a T die by a feed block method or a multimanifold method is preferably used.

The extrusion molding method using the T dies will be described in detail. The resin composition constituting the packaging material made of a polypropylene film is extruded with each extruder according to the T dies method, and a roll or a temperature adjustable roll is adjustable. The method of cooling and winding up using a water tank, or the method of cooling and winding up the said melt by an air cooling method or a water cooling method, etc. are mentioned.

The packaging material obtained is a low stretched or substantially unstretched film of a degree which is slightly stretched by tension or the like during winding.

The packaging material according to the present invention can be printed by applying a surface treatment depending on the application. Although the method of surface treatment is not specifically limited, In general, you may perform corona discharge treatment, a flame treatment, etc. in order to improve adhesiveness with a printing ink. In addition, the shaving surface to which surface treatment is applied is not specifically limited, Any one surface or both surfaces may be sufficient.

Since the packaging material by this invention surface-treated in this way is excellent in print pitch stability, a high precision printing film is obtained. The surface on which the printed layer is formed is not particularly limited, so the base layer or the surface layer may be used.

Hereinafter, although an Example and a comparative example are given and this invention is demonstrated, this invention is not limited to these Examples. In addition, the raw material resin of the packaging material used in the following example and the comparative example is shown in Table 1, and the crystal nucleating agent used is shown in Table 2.

[Table 1]

Suzy Grade name Ethylene
content
(mass%) Butene
content
(mass%) MFR
(g / 10 min) Melting point
(℃) crystallization
Temperature
(℃) Resin A Propylene
Homopolymer FLX80G7
(Sumitomo Chemical Co., Ltd. product)
-
- 7.5 165 116.7 Resin B Propylene
Homopolymer PC600A
(San Aroma Co., Ltd. product)
-
- 7.0 164 114.0 Resin C Propylene
Homopolymer FLX80G1
(Sumitomo Chemical Co., Ltd. product)
-
- 9.0 161 113.4 Resin D Propylene
Homopolymer FB3EBT
(Product made in Nippon Polypro)
-
- 9.0 157 109.3 Resin E Propylene
Random Copolymer (propylene-ethylene copolymer) FW3GT
(Product made in Nippon Polypro) 3.4
- 7.0 146 107.0 Resin F Propylene
Random Copolymer (propylene-ethylene-butene copolymer) FW4BT
(Product made in Nippon Polypro) 3.2 1.5 7.0 137 104.0 Resin G Propylene
Random Copolymer (propylene-ethylene copolymer) WFW4
(Product made in Nippon Polypro) 4.2
- 7.5 135 98.0 Resin H Propylene
Homopolymer Erestor star-320 (* 1)
(Kao Co., Ltd. product)
-
- 35.0 160 115.0 Resin I Propylene
Random Copolymer (propylene-ethylene copolymer) Rickemaster-PAR-380 (* 2)
(理 硏 vitamin Co., Ltd. product) 4.6
- 15.0 137 95.0

* 1: Masterbatch containing 80 mass% of polypropylene and 20 mass% of antifogging agents (glycerol fatty acid ester, stearic acid diethanolamine, stearyl alcohol)

* 2: masterbatch containing 90 mass% of polypropylene and 10 mass% of antifogging agents (glycerin fatty acid ester, higher fatty acid N, N bis (2-hydroxyethyl) fatty amine)

[Table 2]

Kinds Grade name Remarks Nuclear agent I Phosphate Aluminum Salt Product made in ADEKA Corporation
Adecastab NA21 - Nuclear agent Ⅱ Sorbitol derivatives Clearmaster -PP-RM H200 (* 1) made by Daishin Seiko Kogyo Co., Ltd. 10 mass%
MB Nucleus III Polybutene-1 BL4000 made by Mitsui Chemicals -

* 1: MB base resin: polypropylene homopolymer

10 mass% MB means a masterbatch containing 10 mass% of nucleating agents.

About the measurement of resin, film properties, etc. in an Example and a comparative example, it carried out by the following method.

(1) copolymerization composition

It measured on the following conditions using the nuclear magnetic resonance spectrometer (JNM-GSX-270 ( ¹³ C-nuclear resonance frequency 67.8 MHz) by Nippon Denko Co., Ltd.).

Measurement mode: ¹ H-complete decoupling

Pulse width: 90 degrees pulse / pulse repetition time: 3 seconds

Total recovery (accumulation): 10000

Solvent: Mixed solvent of orthodichlorobenzene / heavy benzene (76/24% by volume)

Sample concentration: 120mg / 2.5ml solvent

Measurement temperature: 120 ℃

Copolymer composition was measured according to M. Kakugo, Y. Naito, K. Mizunama, T. Miyatake, [Macromolecules, 15, 1150 (1982)].

(2) Melt mass flow rate (MFR)

MFR was measured at 230 degreeC based on JISK7210.

(3) Tearing direction (straight tearing straight line)

The test piece of 300 mm of longitudinal directions x 210 mm of horizontal directions is cut out from a film. Two cutting lines 15 mm in length are formed at the center of the short side (lateral direction) of the test piece so as to be 10 mm apart. Hold the center (between cutting lines) by hand, pull the film in the longitudinal direction of the film at a speed of about 150 mm / sec. The width of the torn rectangular portion at 150 mm from the cutting line position was measured and evaluated as follows. The linear cutoff of tearing is best when the width is 10 mm. In addition, the measurement temperature was left to stand in a thermostatic bath at 23 degreeC and 120 degreeC for 10 minutes, and was left to stand at room temperature for 2 minutes.

○: when the width of the torn rectangular portion is 10 to 15 mm

(Triangle | delta): When the width | variety of the torn square part exceeds 15 mm and is less than 20 mm

X: When the width of the torn rectangular portion is less than 10 mm or exceeds 20 mm

(4) tear strength

It measured at the temperature of 23 degreeC and 70 degreeC based on JISK7128-1.

(5) transparency (haze)

It measured based on JISK7105.

(6) Melting point and crystallization temperature measured by differential scanning calorimeter

After weighing about 5 to 6 mg of sample, it was sealed in an aluminum container, and heated up to 230 ° C. in a nitrogen stream supplied at 20 ml / min by a differential scanning measurement meter (DSC6200R manufactured by Seiko Electronics Co., Ltd.) After holding for minutes, it was then cooled to 20 ° C. at a temperature reduction rate of 10 ° C./min. Next, the peak temperature showing the maximum endotherm in the endothermic curve obtained when the temperature was raised to 230 ° C at a temperature increase rate of 10 ° C / min was taken as the melting point. In addition, the crystallization temperature melt | dissolved once after melt | dissolving resin based on JISK7121, and measured the temperature at which crystallization starts.

(7) tensile modulus

A sample having a width of 10 mm and a length of 100 mm was cut from the film in the direction in which the film flows during film forming, and both ends of the sample were fixed to a chuck of a tensile tester (autograph: manufactured by Ishimatsu Co., Ltd.). In this case, it adjusts so that the chuck spacing of the longitudinal direction of a sample may be 20 mm. Tensile tests were performed at a tensile rate of 20 mm / min to create a tensile stress-strain curve.

Tensile modulus was calculated by the following formula using the first straight line of the tensile stress-strain curve.

Em = △ δ / △ ε

Em: Tensile Modulus

Δδ: stress difference due to the average cross-sectional area of the sample material between two straight lines

Δε: difference in deformation between two identical points

(8) dimensional change rate

After cutting 100 mm in width and 100 mm in length from the film in the direction of film flow during film forming processing, placing a 10 N weight and placing it in an oven heated in an atmosphere of 100 ° C. for 10 minutes, and leaving it in a 23 ° C. atmosphere for 2 minutes. The rate of dimensional change was measured.

(9) Odor occurs

Ten test pieces (300mm × 210mm) of the film formed were sealed in a glass bottle of volume 300ml, left in a thermostat at 120 ° C. for 1 hour, and left at room temperature for 30 minutes, and the sensory test was carried out through 10 people for the odor in the bottle. It was carried out to determine the presence of odor.

(Circle): When ten people judge that there is no odor

(Triangle | delta): When 1-4 people judge that there is a bad smell

X: When 5-10 people judge that there is a bad smell

(10) anti-fog evaluation

The film is cut into 100 mm x 100 mm, 50 ml of tap water is placed in a 100 ml beaker, covered with a beaker so that the anti-fogging surface becomes an inner surface, and left in a refrigerator at 5 ° C. After 30 minutes and after 24 hours, water droplets adhere to the film. The state was visually observed and evaluated as follows.

○: not cloudy at all

△: slightly blurred

×: blurred (contents not visible)

(11) heat sealing properties

The maximum strength of the film when the corona treated surface and the corona untreated surface are overlapped with each other and heat-sealed under the following conditions is obtained by using a tensile tester (autograph: manufactured by Ishimatsu Co., Ltd.) at 180 mm at a width of 15 mm and a tensile speed of 300 mm / min. Tensile tests were carried out and evaluated in the following two steps.

⊙ Heat sealing condition: Upper sealing: Temperature 160 ℃ (Lower sealing temperature: Room temperature), Pressure 0.1MPa, Time 1 second

○: adhesive strength 3.0N / 15mm or more

×: adhesive strength less than 3.0N / 15mm

Example 1

As a raw material resin for film, 99.8 mass% of resin A (propylene homopolymer (FLX80G7 by Sumitomo Chemical Co., Ltd.) of melting point 165 degreeC) shown in Table 1 was blended by 0.2 mass% of nucleating agent I shown in Table 2, and extruded at 250 degreeC with a 65 mm diameter extruder. The resulting resin was pelletized to prepare a base layer. Resin E (the propylene-ethylene random copolymer (FW3GT by Nippon Polypro Co., Ltd.) whose ethylene content is 3.4 mass% and melting point 146 degreeC) shown in Table 1 was used as resin for 1st surface layer. Next, the first surface resin was supplied to the extruder A (50 mmφ extruder) and the substrate resin was extruded to the extruder B (75 mmφ extruder), melted at 250 ° C., and then melted at 250 ° C. using a co-extrusion method using a feed block. Extruded by a phosphorus T die, and adjusted so that the first surface layer was 5 µm and the substrate layer was 20 µm while cooling and solidifying on a cooling roll at 40 ° C to form a film having a total thickness of 25 µm, and the surface tension was 40 mN / After the corona discharge treatment was applied so as to be m, the resultant was wound by a winding machine to obtain a non-oriented film. The obtained film was excellent in tear direction, tear strength was small, and heat sealing property was favorable.

Examples 2 to 3

The first surface layer was adjusted to 2 μm and the base layer was 23 μm, so that the total surface thickness was 25 μm (Example 2), the first surface layer was adjusted to 10 μm, and the base layer was 15 μm. Except having changed into, it formed into the film similarly to Example 1, and obtained the unstretched film. The obtained film was excellent in tear direction, had small tear strength, and had good heat sealing characteristics.

Example 4

Resin F (the ethylene content is 3.2 mass%, the butene content is 1.5 mass%, and the propylene-ethylene-butene copolymer whose melting point is 137 degreeC) which showed the resin for 1st surface layer of Example 1 (FW4BT by Nippon Polypro Co., Ltd.) Except having used for), it formed into a film similarly to Example 1, and obtained the unstretched film. The obtained film was excellent in tear direction, had small tear strength, and had good heat sealing characteristics.

Example 5

The resin for the first surface layer of Example 1 was used as resin G shown in Table 1 (propylene content of propylene-ethylene random copolymer (WFW4 metalocene catalyst system made by Nippon Polypro) having a ethylene content of 4.2% by mass and a melting point of 135 ° C). Except for all, film formation was carried out similarly to Example 1, and the unstretched film was obtained. The obtained film was excellent in tear direction, had small tear strength, and had good heat sealing characteristics.

Example 6

0.2 mass% of nucleating agent I shown in Table 2 was blended with 99.8 mass% of resin B (propylene homopolymer (PC600A by San Aroma) of melting point 164 degreeC) shown in Table 1, and the base resin of Example 1 was used as a 65 mm diameter extruder. Except having used the thing extruded and pelletized at 250 degreeC, it formed into the film similarly to Example 1, and obtained the unstretched film. The obtained film was excellent in tear direction, had small tear strength, and had good heat sealing characteristics.

Example 7

Except having made the thickness of the base layer of Example 1 into 30 micrometers, and made the 1st surface layer thickness into 10 micrometers, and totaling it to 40 micrometers in all, it formed into a film similarly to Example 1, and obtained the unstretched film. The obtained film was excellent in tear direction, had small tear strength, and had good heat sealing characteristics.

Example 8

Resin obtained by blending 0.2 mass% of nucleating agent I shown in Table 2 with 99.8 mass% of resin A shown in Table 1, and extruding at 250 degreeC with the 65 mm diameter extruder was used for the base material. Resin E shown in Table 1 was used as resin for the 1st surface layer and the 2nd surface layer. After supplying the resin for the first surface to the extruder A (50 mmφ extruder), the resin for the base layer to the extruder B (75 mmφ extruder), and the resin for the second surface layer to the extruder C (50 mmφ extruder), heat-melting to 250 ° C. Extruded by a T die of 1.2 mm die lip using a co-extrusion method, and adjusted so that the first surface layer is 5 µm, the base layer is 15 µm, and the second surface layer is 5 µm while cooling and solidifying on a cooling roll at 40 ° C. It was made into a film of 25 micrometers in total, and the corona discharge treatment was applied to the surface surface of a 2nd surface layer so that surface tension might be 42 mN / m, and it wound up by the winding machine, and obtained the unstretched film. The obtained film was excellent in tear direction, tear strength was small, and heat sealing property was favorable.

Example 9

As a resin for the 1st surface layer and the 2nd surface layer of Example 8, except having used resin G shown in Table 1, it formed into a film similarly to Example 8, and obtained the unstretched film. The obtained film was excellent in tear direction, had small tear strength, and had good heat sealing characteristics.

Example 10

Example 1 except that the first surface layer resin of Example 1 blended 0.2 mass% of the nucleating agent I shown in Table 2 with 99.8 mass% of the resin E shown in Table 1, and extruded and pelletized at 250 degreeC with the 65 mm diameter extruder. Both were formed similarly and the unstretched film was obtained. The obtained film was excellent in tear direction, had small tear strength, and had good heat sealing characteristics.

Example 11

97 mass% of resin A shown in Table 1, and 3 mass% of resin H (antifogant masterbatch (Erosomer Star-320 by Kao Corporation) using propylene homopolymer as a base resin) were blended. The resin obtained by blending 0.2 mass% of nucleating agent I shown in Table 2 with 99.8 mass% of the said blends, extruding at 250 degreeC with the 65 mm diameter extruder, and pelletizing was used for the base material. 95 mass% of Resin E shown in Table 1, and 5 mass% of Resin I (Anti-foamer masterbatch (Rikemaster PAR-380 by Ribita vitamin company) using a propylene-ethylene random copolymer as a base resin) are blended for a 1st surface layer. Except having used as a film, it formed into the film similarly to Example 1, and obtained the unstretched film. The obtained film was excellent in tear orientation, was small in tear strength, had good heat sealing properties, and had good antifogging properties.

Comparative Example 1

Except not adding a nucleating agent to the base layer of Example 1, it formed into the film similarly to Example 1, and obtained the unstretched film. The obtained film was inferior in tear direction and was large in tear strength.

Comparative Example 2

Except having made the compounding quantity of the nucleating agent I added to the base layer of Example 1 into 0.025 mass%, it formed into the film similarly to Example 1, and obtained the unstretched film. The obtained film was inferior in tear direction and was large in tear strength.

Comparative Example 3

All of the films were formed in the same manner as in Example 1 except that the first surface layer was adjusted to 20 µm and the substrate layer was set to 5 µm. The obtained film was inferior in tear direction and was large in tear strength.

Comparative Example 4

All of the films were formed in the same manner as in Example 1 except that the first surface layer was adjusted to be 0.5 µm and the base layer was 24.5 µm, and the total thickness was changed to 25 µm. The obtained film was excellent in tear direction and had small tear strength, but was inferior in heat sealing characteristics.

Comparative Example 5

99.8 mass% of resin C (propylene homopolymer (FLX80G1 manufactured by Sumitomo Chemical Co., Ltd.) having a melting point of 161 ° C.) shown in Table 1 was blended with 0.2 mass% of nucleating agent I shown in Table 2 and extruded at 250 ° C. with a 65 mmφ extruder, and pelletized. Except having used obtained resin for the base layer, it carried out similarly to Example 1, and formed into a film and obtained the unstretched film. The obtained film was inferior in tear direction.

Comparative Example 6

99.8 mass% of resin D ((propylene homopolymer (FB3EBT manufactured by Nippon Polypro)) having a melting point of 157 ° C. was blended with 0.2 mass% of nucleating agent I shown in Table 2 and extruded at 250 ° C. with a 65 mmφ extruder to pellets. The film was formed in the same manner as in Example 1 except that the obtained resin was used for the base layer, thereby obtaining a non-stretched film.

Comparative Example 7

Except having used the nucleating agent added to the base layer of Example 1 as nucleating agent II (sorbitol derivative) shown in Table 2, it carried out similarly to Example 1, and obtained the unstretched film. Odor was generated in the obtained film. The tear direction was also slightly inferior.

Comparative Example 8

Except having blended 5 mass% of nucleating agent III shown in Table 2 with 95 mass% of resin A shown in Table 1 as base resin, it formed into a film similarly to Example 1, and obtained the unstretched film. The obtained film was inferior in tear direction and was large in tear strength.

The laminated constitution of the packaging material obtained by the above Example and the comparative example was put together in Table 3, and was shown. In addition, the results of these Examples and Comparative Examples are summarized in Table 4.

[Table 3]

Extruder A (Surface 1) Extruder B (base) Extruder C (Surface 2) gun
thickness
(Μm)
Of substrate thickness to total thickness
ratio
(%) use
Suzy Nucleating agent Antifog
Addition amount
(mass%)

thickness
(Μm) use
Suzy
Nucleating agent Fence
My
adding
Amount
(quality
Volume%)


thickness
(Μm)

use
Suzy
thickness
(Μm) Kinds Addition amount
(mass%) Kinds adding
Amount
(quality
Amount Example 1 Resin E - - - 5 Resin A Nuclear agent I 0.2 - 20 - - 25 80 Example 2 Resin E - - - 2 Resin A Nuclear agent I 0.2 - 23 - - 25 92 Example 3 Resin E - - - 10 Resin A Nuclear agent I 0.2 - 15 - - 25 60 Example 4 Resin F - - - 5 Resin A Nuclear agent I 0.2 - 20 - - 25 80 Example 5 Resin G - - - 5 Resin A Nuclear agent I 0.2 - 20 - - 25 80 Example 6 Resin E - - - 5 Resin B Nuclear agent I 0.2 - 20 - - 25 80 Example 7 Resin E - - - 10 Resin A Nuclear agent I 0.2 - 30
- - 40 75 Example 8 Resin E - - - 5 Resin A Nuclear agent I 0.2 - 15 Resin E 5 25 60 Example 9 Resin G - - - 5 Resin A Nuclear agent I 0.2 - 15 Resin G 5 25 60 Example 10 Resin E Nuclear agent I 0.2 - 5 Resin A Nuclear agent I 0.2 - 20 - - 25 80 Example 11 Resin E / Resin I
(*One) - - 0.5 5 Resin A / Resin H
(*2) Nuclear agent I 0.2 0.588 20 - - 25 80 Comparative Example 1 Resin E - - - 5 Resin A none none - 20 - - 25 80 Comparative Example 2 Resin E - - - 5 Resin A Nuclear agent I 0.025 - 20 - - 25 80 Comparative Example 3 Resin E - - - 20 Resin A Nuclear agent I 0.2 - 5 - - 25 20 Comparative Example 4 Resin E - - - 0.5 Resin A Nuclear agent I 0.2 - 24.5 - - 25 98 Comparative Example 5 Resin E - - - 5 Resin C Nuclear agent I 0.2 - 20 - - 25 80 Comparative Example 6 Resin E - - - 5 Resin D Nuclear agent I 0.2 - 20 - - 25 80 Comparative Example 7 Resin E - - - 5 Resin A Nuclear agent Ⅱ 0.2 - 20 - - 25 80 Comparative Example 8 Resin E - - - 5 Resin A Nucleus III 5 - 20 - - 25 80

(* 1): Resin E / Resin I = 95 mass% / 5 mass%

(* 2): Resin A / resin H = 97 mass% / 3 mass%

[Table 4]

Hey
(%)

Seal
Elastic modulus
(%)
size
Rate of change
(%)
Tear direction
(mm) Tear strength (N)
Trousers
Tear method stink
Heat sealing properties


Anti-fogging 23 ℃ 120 DEG C 23 ℃ 70 ℃ practice
Example 1 1.8 1300 8.8 12 ○ 13 ○ 0.2 0.4 ○ ○ - practice
Example 2 1.8
1400 6.5 12 ○ 13 ○ 0.2 0.4 ○ ○ - practice
Example 3 1.8 1100 9.7 12 ○ 13 ○ 0.2 0.4 ○ ○ - practice
Example 4 1.7 1200 9.2 14 ○ 14 ○ 0.4 0.6 ○ ○ - practice
Example 5 1.6 1200 9.4 14 ○ 15 ○ 0.5 0.7 ○ ○ - practice
Example 6 1.8 1350 8.4 13 ○ 13 ○ 0.2 0.4 ○ ○ - practice
Example 7 2.4 1250 3.3 12 ○ 13 ○ 0.4 0.6 ○ ○ - practice
Example 8 2.0 1100 9.5 13 ○ 14 ○ 0.2 0.4 ○ ○ - practice
Example 9 1.8 1100 9.5 13 ○ 14 ○ 0.3 0.5 ○ ○ - practice
Example 10 1.5 1360 8.1 11 ○ 12 ○ 0.2 0.3 ○ ○ - practice
Example 11 2.0 1280 9.0 13 ○ 14 ○ 0.3 0.4 ○ ○ ○ compare
Example 1 2.3 850 30.2 23 × 29 × 0.7 1.5 ○ ○ - compare
Example 2 2.1 1020 12.1 22 × 27 × 0.6 1.3 ○ ○ - compare
Example 3 2.0 800 35.0 21 × 26 × 0.6 1.2 ○ ○ - compare
Example 4 1.8 1420 6.5 12 ○ 12 ○ 0.3 0.4 ○ × - compare
Example 5 1.7 1080 10.1 17 △ 21 × 0.3 0.6 ○ ○ - compare
Example 6 2.0 1000 12.4 18 △ 23 × 0.3 0.7 ○ ○ - compare
Example 7 1.3 1320 9.1 15 ○ 17 △ 0.4 0.6 △ ○ - compare
Example 8 2.6 1050 13.8 19 △ 26 × 0.5 1.2 ○ ○ -

Claims (3)

In a non-oriented film comprising at least two layers of a base layer and a surface layer, A packaging material made of a polypropylene-based film, which satisfies the following (1) to (3). (1) The base layer contains 99 to 99.97 mass% of propylene homopolymer having a melting point of 162 ° C. or higher and 0.03 to 1 mass% of phosphate ester metal salt as an organic crystal nucleating agent, and has a thickness of 10 μm or more. (2) The surface layer is made of a propylene-? Olefin copolymer having a melting point of 155 ° C. or less, and has a thickness of 1 μm or more. (3) The thickness of the base layer is 50 to 98% of the total thickness of the packaging material. The method of claim 1, The organic crystal nucleating agent is a packaging material of phosphate ester aluminum salt. The method according to claim 1 or 2, 0.1-4 mass parts of antifogging agents are added with respect to 100 mass parts of resin which comprises the said base layer and surface layer, The packaging material formed by applying a corona discharge treatment to the surface of at least one layer.