JPH10119208A - Film having superior processing suitability and bag comprising the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obviate the necessity of powdering and provide superior process passing properties during bag production processes by laminating a polyolefin system non-stretched film containing mainly a polyolefin resin and having a specific value of blocking strength and a base film. SOLUTION: A film having processing suitability comprises a polyolefin non-stretched film containing mainly a polyolefin resin and a base film that are laminated to each other. It is necessary that the polyolefin non-stretched film has a blocking strength of 10g/70mm or less. When it exceeds 10g/70mm, the anti-blocking properties and opening properties are remarkably hindered, this needing a process such as powdering. The slip properties (tanθ) of a film obtained by laminating the polyolefin non-stretched film and the base film should be 0.8 or less. When it exceeds 0.8, not only are the winding properties of the laminated film deteriorated, but also the process passing properties through, for instance, dry laminating and bag producing processes are deteriorated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminated film of a sealant film and a base film such as a biaxially oriented nylon film, a biaxially oriented polyester film, a biaxially oriented polypropylene film and the like. It does not impair the winding property at the time, does not cause blocking over time when the laminated product is left, and furthermore, for example, in the processing step at the time of lamination or bag making, between the sealant film or between the sealant and the base material The present invention relates to a film having excellent workability which does not cause poor slippage or blocking. Further, the present invention relates to a bag comprising the film.

[0002]

2. Description of the Related Art Currently, a biaxially stretched nylon film having excellent pinhole resistance and cold resistance, a biaxially stretched polyester film having excellent heat resistance, waist, and transparency, and excellent moisture proofness are currently used as food packaging films. A biaxially stretched polypropylene film or the like is used. Although these base films have excellent properties as described above, they have relatively high melting points and are inferior in heat sealability because they are biaxially stretched. Therefore, in order to provide heat sealability, a high-pressure method low-density polyethylene, an ethylene / α-olefin copolymer, an ethylene / vinyl acetate copolymer, a polyolefin resin film such as polypropylene, etc. are laminated and used as a sealant material. ing. The sealant material is required to have various functions such as transparency, seal strength, oil resistance, low-temperature sealing property, hot tack property, slip property, blocking resistance, opening property, impact resistance, and suitability for lamination. Its performance varies greatly depending on the resin and additives used. In particular, slip properties, blocking resistance, suitability for lamination,
Opening properties are greatly affected by additives,
Additives that improve these properties include antiblocking agents and slip agents. Organic and inorganic fine particles are used as the anti-blocking agent, and amide compounds and the like are used as the slip agent.

[0003]

Heretofore, in order to improve the slip property and opening property of a film or a bag-made product, it has been attempted to increase the amount of an antiblocking agent or a slip agent to be added. However, for example, when a large amount of a slip agent is added, the slip agent excessively bleeds onto the surface of the sealant before lamination. Sometimes, there is a problem that the heat sealability between the sealant surfaces is hindered. On the other hand, by adding fine particles having a large average particle size as an anti-blocking agent in order to improve the opening property of the bag-made product, a certain effect can be imparted, but the scratch resistance and transparency of the sealant materials are adversely affected. There was a problem of giving. For this reason, measures have been taken to reduce the amount of the slip agent or the anti-blocking agent used and to shake the powder such as starch during dry lamination and bag making to avoid the above problem. However, this not only pollutes around the processing equipment,
Problems such as remarkable deterioration of the appearance of food packaging are caused. Improvements are awaited, but they are not yet in a satisfactory state.

[0004] The present invention is not only a film-formed product, but also a laminated film, a bag-made product, and the like, and the processing steps thereof, and further improves the slip property, blocking resistance, and opening property during long-term storage.
It is an object of the present invention to provide a film having excellent workability, which solves the problem caused by the conventional dusting, and a bag using the film.

[0005]

The above objects are attained by the following inventions. A film having excellent processability, comprising a polyolefin-based resin and a base film (B) laminated with a polyolefin-based unstretched film (A) having a blocking strength of 10 g / 70 mm or less and a base film (B). The film having excellent workability according to claim 1, wherein the laminated film has a slip property (tan θ) of 0.8 or less. 3. A film having excellent workability according to claim 1, wherein said lamination is performed by a lamination method. A bag comprising the film having excellent processability according to any one of claims 1 to 3.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The polyolefin resin constituting the unstretched polyolefin film of the present invention includes, for example, polyethylene, polypropylene, polybutene-1, and the like.
Homopolymers such as poly-4-methylpentene-1, ethylene-propylene copolymer, ethylene-butene-1 copolymer, ethylene-4-methylpentene-1 copolymer, ethylene-hexene-1 copolymer, Ethylene-octene-
1 copolymer, ethylene-decene-1 copolymer-propylene-4-methylpentene-1 copolymer, propylene-butene-1 copolymer, decene-1-methylpentene-
Copolymers such as 1 copolymer and ethylene-propylene-butene-1 copolymer; and further, linear low-density polyethylene, high-pressure low-density polyethylene, and high-density polyethylene. These polyolefin resins may be used alone or in combination of two or more. As the linear low-density polyethylene, ethylene and at least one kind of an α-olefin having 3 to 10 carbon atoms of preferably 0.2 to 20 mol%, more preferably 1 to 10 mol% Or those copolymerized in the gas phase can be mentioned. As the α-olefin, propylene, butene-1, pentene-1, hexene-1,
Heptene-1, octene-1, nonene-1, decene-
1,4-methylpentene-1,4-methylhexene-
1,4,4-dimethylpentene-1 and the like can be used. Among such linear low-density polyethylenes, those having a density in the range of 0.900 to 0.960 g / cm ³ are particularly preferable. In addition, these polyolefin-based resins may optionally contain various additives commonly used in polyolefin compositions, such as anti-blocking agents, heat stabilizers, antioxidants, ultraviolet absorbers, and antistatic agents. It can be used within a range that does not impair the effects of the invention. It is preferable to use spherical fine particles as the anti-blocking agent. The use of spherical fine particles makes it easier to balance the transparency, slipperiness and blocking resistance of the film. The method for producing the polyolefin resin is not particularly limited, and may be either a gas phase method or a liquid phase method. The catalyst is not limited, and may be a Ziegler-Natta catalyst, a vanadium oxytrichloride, a vanadium tetrachloride, an organic aluminum, a metallocene catalyst, or a mixture thereof.
As the polyolefin resin, it is preferable to use a resin that has been deodorized by, for example, decompression treatment. Also JISK7
It is preferable to use a melt flow rate (MI) measured at 230 ° C. in accordance with No. 210 of 1 to 15 g / 10 min. The polyolefin-based unstretched film of the present invention can be obtained by molding the above-mentioned polyolefin-based resin by a co-extrusion method. For example, an inflation molding method using a circular die, a T die molding method using a T die, and the like are employed. When performing T-die molding, the draft rate should be 1 to 8
0, it is preferable to select the resin temperature from the range of 190 to 300 ° C. The thickness of the polyolefin-based unstretched film of the present invention is usually in the range of 5 to 150 µm, more preferably in the range of 20 to 120 µm.

The non-stretched polyolefin film of the present invention must have a blocking strength of 10 g / 70 mm or less. The blocking strength is a measure that can efficiently evaluate the blocking and the opening property of a film-formed product, a laminated film, a bag-made product, and the like. The smaller the value is, the better the blocking resistance and the opening property are. When the blocking strength exceeds 10 g / 70 mm, the blocking resistance and the opening property are significantly impaired, so that a step such as dusting is required. In consideration of the handling properties and process passability of the film-formed product, the laminated film, and the bag-formed product, the preferable range of the blocking strength is 5 g / 70 mm or less.

In the present invention, the blocking strength (g / 7)
0mm) means that 8cm / 12cm film sealant faces are superimposed on each other, and after 50 ° C for 30 minutes,
A 5 cm × 5 cm portion is pressed at 50 ° C. × 15 minutes by applying a load of 40 kg with a hot press, and is pressed at 23 ° C. × 65%
Under the conditions of RH, according to ASTM D-1893,
It is a peel strength measured by a tensile tester.

The polyolefin-based unstretched film of the present invention may be a single-layer film or a laminated film of the polyolefin-based resin containing an anti-blocking agent and a slipping agent.
In particular, a laminated film comprising a polyolefin-based unstretched film, wherein at least one outer layer contains an antiblocking agent and a slip agent, each layer from the layer to the other outer layer has a density gradient, and the other outer layer Is composed of the highest density polyolefin resin, and the high density is 0.9%.
It can be obtained by forming a laminated film having a thickness of 00 to 0.945 g / cm ³ .

The polyolefin-based unstretched film of the present invention contains an antiblocking agent and a slipping agent. When the film is laminated with a substrate, the antiblocking agent in the laminate surface layer of the polyolefin-based unstretched film is used. And a slip agent tend to hinder the adhesion to the substrate. Also, the slip agent tends to shift to the lower density side. For this reason, the polyolefin-based unstretched film is a laminated film having a density gradient between each layer, and at least one outer layer (sealant surface layer) contains an antiblocking agent and a slip agent, and the other outer layer (laminate surface layer). ) Is preferably made of the highest density polyolefin resin.

Further, the polyolefin-based unstretched film of the present invention preferably contains no antiblocking agent and / or slip agent in at least the other outer layer (laminated surface layer). The other outer layer is a layer that is bonded to the base material through an adhesive such as a polyether-based or polyester-based adhesive, and is an important layer that ultimately affects the strength and the like of the laminated film. When an antiblocking agent and / or a slip agent enters the layer, it not only tends to inhibit the adhesion to the substrate, but also causes a reduction in the laminate strength between the sealing material and the substrate. or,
The haze of the film tends to increase and the transparency tends to deteriorate.

The laminated film is preferably composed of 2 to 7 layers, more preferably 3 layers, from the viewpoint of slipperiness, blocking resistance, breaking elongation, Young's modulus, impact strength and heat sealing strength. .

The anti-blocking agent used in the present invention is not particularly limited, but inorganic and / or organic fine particles are preferred. Specifically, examples of the organic fine particles include, for example, polymethyl methacrylate, polystyrene, polyamide, and the like, which are made of a polymer that does not substantially deform and obtained by emulsion polymerization, suspension polymerization, or the like. Examples of the inorganic fine particles include silica, zeolite, diatomaceous earth, talc, kaolinite, and amorphous aluminosilicate. Organic film-based polymethyl methacrylate is preferred from the viewpoint of transparency of the film, and inorganic particle-based silica, zeolite and diatomaceous earth are preferred from the viewpoint of cost. The average particle size of the anti-blocking agent is not particularly limited, but may be 2 to 15 in consideration of appearance, transparency and blocking properties.
It is preferably about μm, more preferably 5 to 10 μm.

The amount of the antiblocking agent used in the present invention is not particularly limited, and it can be used freely within a range that does not impair the physical properties, appearance, transparency, etc. of the film. 0.01 to 3 parts by weight, preferably 0.05 to 2 parts by weight. When the polyolefin-based unstretched film of the present invention is laminated, preferred amounts of the antiblocking agent to be blended in each layer are as follows. In one outer layer, 0.00.0 parts by weight based on 100 parts by weight of the polyolefin resin.
1 to 3 parts by weight is preferable, and 0.05 to 2 parts by weight is more preferable. In the other outer layer, it is preferable that no anti-blocking agent is blended. In the intermediate layer, the amount is preferably 0.01 to 2 parts by weight, more preferably 0.05 to 1 part by weight, based on 100 parts by weight of the polyolefin resin.

The method of blending the anti-blocking agent into the polyethylene-based unstretched film of the present invention can be a master batch method or a pellet blending method immediately before film formation, and is not particularly limited.

As the slip agent used in the present invention, known ones can be used, and there is no particular limitation. Examples of the slip agent having a high bleeding speed include liquid paraffin and hydrocarbon waxes such as polyethylene wax. Slip agents, metal soap-based slip agents such as calcium stearate and magnesium stearate, and amide-based slip agents such as oleamide, erucamide, and behenic acid amide are included. Further, as the slip agent having a relatively low bleed rate, for example, ethylene bisoleic acid amide, hexamethylene bis oleic acid amide, ethylene bis erucamide, etc., these slip agents having a relatively low bleed rate can be used alone. However, it is preferable to use the amide slip agent in combination. As the slip agent, oleic acid amide, or a combination system of erucic acid amide and ethylenebisoleic acid amide is more preferable, from the viewpoint of handling properties and slipping properties.

The amount of the slip agent used in the present invention is not particularly limited, and the slip agent can be used freely as long as the slip property of the film immediately after film formation and the heat sealing property as a sealant material are not impaired. It is usually 0.01 to 0.5 part by weight, preferably 0.02 to 0.35 part by weight based on part by weight. When the polyolefin-based unstretched film of the present invention is laminated, preferred amounts of the slip agent blended in each layer are as follows. In one outer layer, the amount is preferably 0.01 to 0.05 part by weight, more preferably 0.02 to 0.35 part by weight, based on 100 parts by weight of the polyolefin resin. It is preferable not to mix a slip agent in the other outer layer. In the intermediate layer, the polyolefin resin 10
0.01 to 0.05 part by weight, preferably 0.02 to 0.3 part by weight, based on 0 part by weight.

The method of blending the slip agent into the polyolefin-based unstretched film of the present invention can be a master batch method or a pellet blending method immediately before film formation, and is not particularly limited.

When the polyolefin-based unstretched film of the present invention is laminated, the thickness ratio of each layer is preferably 0.2 to 5 with respect to the thickness 1 of the other outer layer, and 0.2 to 5; 5 to 3 are more preferred. In addition, the total thickness of the intermediate layer is preferably 1 to 25, more preferably 2 to 20, with respect to the thickness 1 of the other outer layer. In particular, when the laminated film has a three-layer structure, the thickness ratio of the other outer layer / intermediate layer / one outer layer = 1/2/1 to 1/1, in consideration of film forming properties, film physical properties and film functional aspects. About 20/1 is preferable.

The polyolefin-based unstretched film of the present invention may optionally contain an antistatic agent, a weathering agent, an antioxidant,
Known additives such as a heat stabilizer and a colorant may be blended.

Examples of the base film used in the present invention include a polyolefin-based unstretched film and a biaxially stretched plastic film, but are not particularly limited, but a biaxially stretched plastic film is preferable.
From the viewpoints of Young's modulus, impact strength, heat sealing strength and the like, biaxially stretched nylon film, polyester film, polypropylene film and the like are more preferable. Further, biaxially stretched nylon films, polyester films and polypropylene films coated with polyvinylidene chloride or the like, biaxially stretched nylon films having a vapor deposition layer, polyester films and the like can also be mentioned. Depending on the purpose, a metal foil, paper, cellophane, or the like may be laminated on the biaxially stretched film. The thickness of the base film varies depending on the purpose, but is usually 5 to 30 μm, preferably 1 to 30 μm.
0 to 25 μm.

The film obtained by laminating the non-stretched polyolefin film of the present invention and the base film has a slip property (tan θ) of 0.8 or less. The slip property indicates the surface friction characteristics of not only a film-formed product but also a laminated film and a bag-formed product. The smaller the value, the better the slip property. When the slip property (tan θ) exceeds 0.8, not only does the winding property of the laminated film become impaired, but also the processability in, for example, the dry laminating and bag-making processes tends to be deteriorated. Become. Therefore, in consideration of the winding characteristics of the laminated product and the process passability during processing, a more preferable slip property (tan θ) is 0.4.
It is as follows.

In the present invention, the slip property is measured by using a friction angle measuring device manufactured by Toyo Seiki Co., Ltd., and measuring the slip angle θ of the film sealant surfaces at an inclination rising speed of 3.3 ° / sec ( Friction area 62cm ² , load 1kg)
It is represented by tan θ.

The lamination method used in the present invention is a lamination method in which lamination is performed by heat or an adhesive. More specifically, examples include wet lamination, dry lamination, solvent-free lamination, hot lamination, and extrusion lamination. The type is selected depending on the purpose, application and the like, but dry lamination and extrusion lamination are more preferable.

The bag of the present invention has a blocking strength of 10 g /
It comprises a laminated film comprising the above-mentioned polyolefin-based unstretched film having a size of 70 mm or less and a base film. By using a laminated film having excellent blocking resistance and slip property (tan θ), not only is the process passing property at the time of bag making good, but also because there is no need to shake starch or the like, there is no contamination around the device. Also, it did not affect the appearance of the bag-made product at all. Further, even if the bag-made product using the laminated film of the present invention is left in a state of high temperature and high humidity (50 ° C.-80% RH) and low temperature and low humidity (10 ° C.-20% RH), the opening property is changed. It was not possible to maintain the same favorable state immediately after bag making.

The bag making method may be performed by a method known per se, for example, a bag making method with a simple manual sealer, an automatic bag making method with a three-side seal or a fusing seal bag making machine, and the like.

[0027]

Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. The method of measuring characteristic values in the examples and comparative examples will be described.

(1) Density The density was measured according to the method specified in JIS-K6760.

(2) Haze Measured according to JIS-K7105. The smaller the value, the better the transparency.

(3) Slip property Using a friction angle measuring device manufactured by Toyo Seiki Co., Ltd., the slip angle θ was measured for the sealant surfaces of the film at an inclination rising speed of 3.3 ° / sec (the friction area was 62 cm ² , Load 1kg)
And expressed as tan θ. The smaller the value, the better the slip property.

(4) Blocking ability 5 cm of the sealant face of the 8 cm × 12 cm film
After superimposing for 30 minutes at 50 ° C. and applying a load of 40 kg by hot pressing,
C. for 15 minutes at 23.degree. C. and 65% RH.
m). The smaller the value, the better the blocking resistance.

The raw materials used in Examples and Comparative Examples are shown below. (1) Polyethylene resin R1: MI = 2, density = 0.935 g / cm ³ R2: MI = 2, density = 0.920 g / cm ³ R3: MI = 2, density = 0.910 g / cm ³ R4: MI = 2, density = 0.908 g / cm ³ (2) Polypropylene resin R5: MI = 2, density = 0.900 g / cm ³ R6: MI = 2, density = 0.910 g / cm ³ (3) Ethylene Vinyl acetate copolymer resin R7: MI = 2, density = 0.922 g / cm ³ (4) Antiblocking agent (ABA) ABA1: average particle size 10 μm, organic fine particles ABA2: average particle size 2 μm, organic fine particles ABA3 : Average particle size 6 μm, inorganic fine particles (5) Slip agent (SA) EA: erucamide EBA: ethylenebisoleic amide

Examples 1-3 A polyolefin-based unstretched film shown in Tables 1 and 2 and a biaxially-stretched nylon film (15 μm) were dry-laminated (adhesive: ether-based, without powder shaking) to obtain a laminated film. Obtained. Table 3 shows the slip property (tan θ) and processability of the laminated film.

Examples 4 to 6 Using the polyolefin-based unstretched films of Examples 1 to 3 and a biaxially stretched nylon film (15 μm), a powder shaking step was added at the time of dry lamination. Lamination was performed to obtain a laminated film. Table 4 shows the slip property (tan θ) and processability of the laminated film.

Examples 7 to 9 The non-stretched polyolefin films of Examples 1 to 3 and the biaxially stretched polyester film (12 μm) were extruded and laminated (using low-density polyethylene without powder shaking) to obtain a laminated film. Table 5 shows the slip property (tan θ) and processability of the laminated film. The process passability described in Tables 3 to 5 is as follows. Process passability ○: Good slip property (between film and roll), no slippage, no wrinkle ×: Poor slip property (between film and roll), slippage, wrinkled

As is clear from the results of Tables 3 and 5, according to the present invention, the processability during lamination was good, and the appearance of the obtained laminated film was not problematic. Film is slippery (tan
θ) Displacement or wrinkling due to failure occurred, and the process passability during lamination was quite poor. When the film was wound, the laminate film had irregularities on the surface and air bubbles, so that the appearance was poor. On the other hand, from the results in Table 4, it can be seen from the results shown in Table 4 that when the dusting is performed during the laminating step, the slipping property is improved, so that the passability of the process is improved. It became clear that the powder adhered to the surface of the laminate film, the transparency was lowered, and the appearance was deteriorated. From the above, according to the present invention, the laminating process can be performed without any dusting, so that its usefulness is very large.

Examples 10 to 12 Using the laminated films obtained in Examples 1 to 3, bags were formed on a weaving machine (size: 150 mm × 210 mm, speed: 21 m / min, seal width: 10 mm, seal temperature: 1).
50 ° C.), and the results of evaluating the suitability for bag making are shown in Table 6.

Examples 13 to 15 Using the laminated films obtained in Examples 4 to 6, bag making was performed in the same manner as in Example 10, and the suitability for bag making was evaluated.
Table 7 shows the results.

As is clear from the results in Table 6, according to the present invention, since the lamination film has a good slip property (tan θ) (Examples 1 to 3), the suitability for bag making is good and there is no problem in appearance. Comparative examples 16 to 2 can be made.
In the case of No. 0, the slip property (tan θ) of the laminated film was poor (Comparative Examples 1 to 5).
In addition, wrinkles were formed on the bag surface, and the appearance was poor.
On the other hand, the results shown in Table 7 revealed the following.
There is no particular problem in suitability for bag making because the film was shaken during lamination.However, powder adheres to all parts of the bag making process and contaminates the periphery of the device. From the viewpoint described above, a problem occurs particularly when filling foods and the like.

[0040]

[Table 1]

[0041]

[Table 2]

[0042]

[Table 3]

[0043]

[Table 4]

[0044]

[Table 5]

[0045]

[Table 6]

[0046]

[Table 7]

[0047]

According to the present invention, excellent processability in laminating and bag making processes is achieved, dusting, which has been a problem in the past, is completely unnecessary, and the problem of contamination in the working process can be solved.
It is possible to provide a laminated film and a bag comprising the same, which significantly improve the appearance. The laminate film of the present invention can be widely developed as a food packaging film or the like.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Tsutomu Isaka 2-2-2, Dojimahama, Kita-ku, Osaka Toyobo Co., Ltd.

Claims (4)

[Claims] 1. A film having excellent workability in which a polyolefin-based unstretched film (A) mainly comprising a polyolefin-based resin and having a blocking strength of 10 g / 70 mm or less and a base film (B) are laminated. 2. The slip property (ta) of the laminated film.
2. The film having excellent workability according to claim 1, wherein (nθ) is 0.8 or less. 3. A film having excellent workability according to claim 1, wherein said lamination is performed by a lamination method. 4. A bag comprising the film having excellent processability according to claim 1.