JP4766220B2 - Polyamide-based laminated film used as a packaging bag - Google Patents

Description

【００３９】
【発明の効果】
本発明の包装用袋として用いられるポリアミド系積層フィルムは、包装用フィルムとして必要なフィルム品質である、滑り性、透明性及び耐屈曲疲労性に優れ、各種の包装材料として用いたときに印刷やラミネートなどを行う加工工程における加工適性が良好であって、加工不良を低減させ、包装袋としたときに輸送時の耐破袋性に優れ、包装用途に適している。[0001]
BACKGROUND OF THE INVENTION
The present invention is a polyamide-based laminated film, particularly excellent in slipperiness and transparency, and has good processability in the process of printing and laminating when used as various packaging materials, and was used as a packaging bag. The present invention relates to a polyamide-based laminated film that is used as a packaging bag having excellent resistance to tearing during transportation.
[0002]
[Prior art]
Conventionally, unstretched films or stretched films made of polyamide resin, represented by nylon 6 and nylon 66, are superior in strength and gas barrier properties compared to films made of other general polymers. In particular, it is widely used as various packaging materials because it has an effect of preventing the contents from being altered when used as a packaging material for hydrated packaging. However, the unstretched film or stretched film made of the above-mentioned conventional polyamide-based resin has poor slipperiness in a high-humidity atmosphere, and troubles such as printing failure and lamination failure due to generation of wrinkles in processing processes such as printing and lamination. In many cases, the operability during film processing cannot be improved.
[0003]
In addition, a packaging bag that wraps food using a film made of a conventional polyamide-based resin has a bag breakage due to vibration or impact during transportation compared to a bag that uses a film made of a polyester-based resin or an olefin-based resin. Although it is excellent, bag breakage may occur depending on the shape of the bag, the contents, the transportation state, and the like.
[0004]
[Problems to be solved by the invention]
The present invention solves the problems of the conventional films made of polyamide resin, is excellent in slipping, transparency and bending fatigue resistance, which is a film quality required as a packaging film, as various packaging materials Used as a packaging bag that has good processability in processing processes such as printing and laminating when used, reduces processing defects, and has excellent resistance to bag breakage during transportation when used as a packaging bag. An object is to provide a polyamide-based laminated film.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, the polyamide-based laminated film used as the packaging bag of the present invention is a polyamide-based resin containing inorganic particles (P1) having an average particle diameter of 0.5 to 3.0 μm on at least one surface. a surface layer is laminated consisting of and an average particle diameter of 3.0 to 5.0 .mu.m in the adjacent layer adjacent to the surface layer, and a feature in that it contains greater inorganic particles than the thickness of the surface layer (P2) To do.
[0006]
In this case, in the polyamide-based laminated film, the thickness of the surface layer can be 40 to 140% with respect to the average particle diameter of the inorganic particles (P1).
[0007]
In this case, the polyamide-based laminated film can have a static friction coefficient of 0.35 or less at 23 ° C. and 65% RH between the surface layers.
[0008]
Furthermore, in this case, the static friction coefficient of the polyamide-based laminated film at 23 ° C. and 80% RH between the surface layers can be 0.50 or less.
[0009]
The polyamide-based laminated film used as a packaging bag of the present invention having the above-described structure is excellent in slipping, transparency and bending fatigue resistance, which is a necessary film quality as a packaging film, and is used as various packaging materials. It has good processability in processing processes such as printing and laminating when it is present, reduces processing defects, and has excellent resistance to bag breakage during transportation when used as a packaging bag, making it suitable for packaging applications.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the polyamide-based laminated film used as the packaging bag of the present invention will be described in detail.
[0011]
The polyamide-based laminated film used as a packaging bag in the present invention is a laminate in which an adjacent layer and a surface layer are laminated in the configuration of adjacent layer / surface layer or surface layer / adjacent layer / surface layer. The polyamide resin forming the layer is the same or different polyamide resin and mainly has an amide unit. In addition to a homopolymer, a copolymer obtained by copolymerizing various copolymerizable monomers in a small amount is used. It can be used, and it may be a mixture of two or more polyamide resins, or a polyester resin, a polyolefin resin, or the like may be mixed within a range that does not impair the characteristics.
[0012]
As the polyamide resin used in the present invention, for example, nylon 6 containing ε-caprolactam as a main raw material can be mentioned. Other polyamide resins include polyamide resins obtained by polycondensation of lactams having three or more members, ω-amino acids, dibasic acids and diamines. Specifically, as lactams, in addition to the above-described ε-caprolactam, enantolactam, capryllactam, lauryllactam, and ω-amino acids include 6-aminocaproic acid, 7-aminoheptanoic acid, and 9-aminononane. Examples of acids, 11-aminoundecanoic acid and dibasic acids include adipic acid, glutaric acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, hexadecadionic acid, eicosandioic acid, eicos Sadienedioic acid, 2,2,4-trimethyladipic acid, terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, xylylenedicarboxylic acid and diamines include ethylenediamine, trimethylenediamine, tetramethylenediamine, hexa Methylenediamine, pentamethyle Diamine, undecamethylenediamine, 2,2,4 (or 2,4,4) -trimethylhexamethylenediamine, cyclohexanediamine, bis- (4,4'-aminocyclohexyl) methane, metaxylylenediamine and the like. , A polymer obtained by polycondensation thereof or a copolymer thereof, such as nylon 6, 7, 11, 12, 6.6, 6.9, 6.11, 6.12, 6T, 6I, MXD6, 6 / 6.6, 6/12, 6 / 6T, 6 / 6I, 6 / MXD6, and the like.
[0013]
The inorganic particles P1 and inorganic particles P2 used in the present invention may be the same or different, and examples thereof include silica, calcium carbonate, barium sulfate, magnesium oxide, alumina, zeolite, and the like. It is also possible to use a material that has been subjected to a coating treatment of Moreover, the shape of these inorganic particles is spherical, cubic, cylindrical, conical, disc-shaped, indeterminate, etc., and can be used according to the purpose of use of the film.
[0014]
As a method of adding inorganic particles to the polyamide-based resin, it can be added at the time of polymerization or at the time of melt extrusion with an extruder to form a master batch, and this master batch is used by adding it to the polyamide-based resin during film production. It can be performed by a known method.
[0015]
The inorganic particles P1 used for the surface layer of the polyamide-based laminated film of the present invention have an average particle size of 0.5 to 3.0 μm, preferably 0.8 to 2.5 μm, It can be set according to transparency. If the average particle diameter of the inorganic particles P1 is smaller than 0.5 μm, sufficient slipping property cannot be obtained, and if it is larger than 3.0 μm, the transparency becomes poor or the problem of missing during printing occurs. It is not preferable.
[0016]
The inorganic particles P2 used in the adjacent layer adjacent to the surface layer of the polyamide-based laminated film of the present invention must have an average particle diameter larger than the thickness of the surface layer. The average particle size of the inorganic particles P2 used depends on the thickness of the surface layer, but is preferably 0.2 to 5.0 μm, and more preferably 0.5 to 3.0 μm. If the average particle diameter of the inorganic particles P2 is smaller than the thickness of the surface layer, the slipping property is not sufficient, and bag breakage may occur during transportation when used as a packaging bag.
[0017]
The content of the inorganic particles P1 and P2 is determined by the required transparency and slipperiness, but is preferably 0.10 to 2.00% by weight, more preferably 0.20 to 1 in the surface layer. 0.000% by weight. If the content of the inorganic particles P1 in the surface layer is less than 0.10% by weight, the effect of improving the slipping property is small, and if it exceeds 2.00% by weight, the transparency is poor or the pressure increase of the filter in the manufacturing process is increased. A problem occurs.
[0018]
In the polyamide-based laminated film of the present invention, the thickness of the surface layer is preferably 40 to 140%, more preferably 50 to 100%, with respect to the average particle diameter of the inorganic particles P1. If the thickness of the surface layer is less than 40% of the average particle diameter of the inorganic particles A, the film may be damaged or the printing may be lost due to the falling off of the inorganic particles during film formation, printing or laminating. This is not preferable because Further, if the thickness of the surface layer is larger than 140% with respect to the average particle diameter of the inorganic particles A, the transparency may be deteriorated, which is not preferable.
[0019]
In addition, the polyamide-based laminated film of the present invention preferably has a static friction coefficient between the surface layers at 23 ° C. and 65% RH of 0.35 or less, and more preferably 0.30 or less. If the coefficient of static friction between the surface layers at 23 ° C. and 65% RH is greater than 0.35, the processing suitability for printing, laminating, etc. may be poor, and bag breakage may occur during transportation when used as a packaging bag. This is not preferable. Moreover, the lower limit of the static friction coefficient is not particularly set, but if it is smaller than 0.10, it is not preferable because winding deviation may occur when wound into a roll shape.
[0020]
Furthermore, in the polyamide-based laminated film of the present invention, the static friction coefficient between the surface layers at 23 ° C. and 80% RH is preferably 0.50 or less, and more preferably 0.45 or less. If the coefficient of static friction between the surface layers at 23 ° C. and 80% RH is greater than 0.50, the slipperiness under high humidity will be poor, and the change in temperature and humidity will cause poor workability such as printing and lamination. Since a broken bag may occur at the time of transportation when used as a packaging bag, it is not preferable.
[0021]
Although there is no restriction | limiting in particular about the method of manufacturing the resin composition which comprises the polyamide-type laminated | multilayer film in this invention, The well-known various additives generally used can be contained as needed. For example, lubricants such as fatty acid amides and fatty acid bisamides, antioxidants such as hindered phenols, phosphate esters, and phosphites, and weathering stabilizers such as triazines, and any antistatic agent, A colorant or the like can be used.
[0022]
The polyamide resin film of the present invention can be formed by a known film forming method. Although it does not specifically limit as a film forming method, T die method, an inflation method, etc. are applied. In order to obtain the polyamide-based laminated film of the present invention, this is preferably biaxially stretched, and the stretch ratio is more preferably 10 times or more in terms of area ratio.
[0023]
As the stretching method, the T-die method sequential biaxial stretching is preferable, excellent in slipperiness and transparency, and has good processability in the process of printing and laminating when used as various packaging materials. It is preferable to include a step of carrying out the longitudinal stretching at a high temperature and a high magnification in order to achieve excellent bag resistance at the time of transportation when used. Furthermore, the difference between the film temperature at the end of the transverse stretching and the heat setting temperature is preferably 50 ° C. or less.
[0024]
【Example】
EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited to the following examples. In addition, the measurement of the characteristic value in this specification was performed by the following method.
[0025]
(1) Average particle diameter The average particle diameter (diameter) was measured using centrifugal sedimentation type particle size distribution analyzer SA-CP4 manufactured by Shimadzu Corporation.
[0026]
(2) Sliding property In accordance with JIS-K-7125, the static friction coefficient between the surface layers of the film was adjusted for 24 hours in a constant temperature and humidity chamber of 23 ° C., 65% RH and 23 ° C., 80% RH, and immediately thereafter. , Measured at 23 ° C. and 65% RH. The coefficient of static friction was 65% RH and 80% RH depending on the humidity used for conditioning.
[0027]
(3) Haze Haze was measured according to JIS-K-7105 using a Nippon Denshoku haze meter.
[0028]
(4) Workability Using a gravure printer, the film running speed is 100 m / min in a 24 ° C., 70% environment, and the film is rolled back 1000 m under the lower running tension, and the workability is evaluated as follows. did.
○: Wrinkles or scratches are not generated on the roll, and the processability is good. Δ: Wrinkles are occasionally generated at the end of the roll, and it is necessary to adjust the processing conditions or weak scratches are generated. ×: End and center of the roll Wrinkles occur in the part, and even if the processing conditions are adjusted, it will not disappear or a severe scratch will occur.
(5) Bag-breaking resistance The package which covered the film which made the bag in the paper box of weight 300g, height 30mm, length 200mm, and width 80mm was put into the cardboard box in 2 rows and 3 steps. The cardboard box had a height of 900 mm, a length of 200 mm, and a width of 160 mm according to the internal method, and was a box without play in a paper box covered with a film. This cardboard box was vibrated for 20 hours in an environment of 5 ° C. × 70% RH with a vibration tester having an amplitude of 50 mm and a vibration speed of 170 times / min. The number of holes generated in the film made on the paper box was counted.
○: Average number of holes is less than 2.0 Δ: Average number of holes is 2.0 or more and less than 4.0 ×: Average number of holes is 4.0 or more
Example 1
An unstretched sheet having the following configuration was obtained using a two-type three-layer coextrusion T-die facility. The layer configuration of the unstretched sheet was a surface layer / adjacent layer / surface layer configuration, the total thickness of the unstretched sheet was 257 μm, and the thickness ratio of each surface layer to the total thickness was 6.7%.
1) Composition for forming an adjacent layer: nylon 6 (relative viscosity = 2.8) is 96.80% by weight, polymetaxylylene adipamide (relative viscosity = 2.1) is 3.00% by weight, silica ( A polymer composition comprising 0.2% by weight of an average particle size of 3.0 μm.
2) Composition for forming the surface layer: 96.15% by weight of nylon 6 (relative viscosity = 2.8), 3.00% by weight of polymetaxylylene adipamide (relative viscosity = 2.1), ethylene bis A polymer composition comprising 0.15% by weight of stearic acid amide and 0.70% by weight of silica (average particle size 1.8 μm).
[0031]
The obtained unstretched sheet was heated in the longitudinal direction to 105 ° C. with a polytetrafluoroethylene roll and stretched 2.5 times, then heated to 95 ° C. with a ceramic roll and stretched 1.5 times, and further a ceramic roll. At 80 ° C. and stretched 1.2 times. Subsequently, the film was preheated to 110 ° C. in a tenter, and stretched 3.8 times in the transverse direction while further raising the film temperature to 215 ° C. Thereafter, heat setting was performed at 220 ° C. to obtain a biaxially stretched film having a thickness of 15 μm. Table 1 shows the results of evaluating the physical properties of the obtained biaxially stretched film.
[0032]
(Example 2)
In Example 1, a biaxially stretched film was obtained in the same manner as in Example 1 except that the thickness ratio of each surface layer to the total thickness was changed to 13.3%. Table 1 shows the results of evaluating the physical properties of the obtained biaxially stretched film.
[0033]
(Example 3)
In Example 1, a biaxially stretched film was obtained in the same manner as in Example 1, except that the thickness ratio of each surface layer to the total thickness was changed to 18.7%. Table 1 shows the results of evaluating the physical properties of the obtained biaxially stretched film.
[0034]
Example 4
In Example 1, a biaxially stretched film was obtained in the same manner as in Example 1, except that the thickness ratio of each surface layer to the total thickness was changed to 5.0%. Table 1 shows the results of evaluating the physical properties of the obtained biaxially stretched film.
[0035]
(Comparative Example 1)
A biaxially stretched film was obtained in the same manner as in Example 1, except that the thickness ratio of each surface to the total thickness in Example 1 was changed to 23.3%. Table 1 shows the results of evaluating the physical properties of the obtained biaxially stretched film.
[0036]
(Comparative Example 2)
An unstretched sheet having the following configuration was obtained using a two-type three-layer coextrusion T-die facility. The layer configuration of the unstretched sheet was a surface layer / adjacent layer / surface layer configuration, the total thickness of the unstretched sheet was 257 μm, and the thickness ratio of each surface layer to the total thickness was 6.7%.
1) Composition for forming an adjacent layer: Nylon 6 (relative viscosity = 2.8) is 97.00% by weight, polymetaxylylene adipamide (relative viscosity = 2.1) is 3.00% by weight Combined composition.
2) Composition for forming the surface layer: 96.15% by weight of nylon 6 (relative viscosity = 2.8), 3.00% by weight of polymetaxylylene adipamide (relative viscosity = 2.1), ethylene bis A polymer composition comprising 0.15% by weight of stearitic acid amide and 0.70% by weight of silica (average particle size 1.8 μm).
[0037]
The obtained unstretched sheet was heated in a longitudinal direction to a ceramic roll 50 ° C. and stretched 3.2 times. Subsequently, it was preheated to 160 ° C. in a tenter and stretched 4.0 times in the transverse direction. Then, the heat setting process was implemented at 220 degreeC, and the 20-micrometer-thick biaxially stretched film was obtained. Table 1 shows the results of evaluating the physical properties of the obtained biaxially stretched film.
[0038]
[Table 1]

[0039]
【The invention's effect】
The polyamide-based laminated film used as the packaging bag of the present invention is excellent in slipperiness, transparency, and bending fatigue resistance, which is a film quality required as a packaging film, and can be printed when used as various packaging materials. It has good processability in the processing step for laminating and the like, reduces processing defects, has excellent resistance to bag breakage during transportation, and is suitable for packaging applications.

Claims (4)

A surface layer made of a polyamide-based resin containing inorganic particles (P1) having an average particle diameter of 0.5 to 3.0 μm is laminated on at least one surface, and the average particle diameter is 3 in an adjacent layer adjacent to the surface layer. in .0～ 5.0 .mu.m, and a polyamide-based multilayer film used as a packaging bag, characterized in that it contains the inorganic particles (P2) greater than the thickness of the surface layer.   The polyamide-based laminated film used as a packaging bag according to claim 1, wherein the thickness of the surface layer is 40 to 140% with respect to the average particle diameter of the inorganic particles (P1).   The polyamide-based laminated film used as a packaging bag according to claim 1 or 2, wherein the static friction coefficient between the surface layers at 23 ° C and 65% RH is 0.35 or less.   4. The polyamide-based laminated film used as a packaging bag according to claim 1, wherein a static friction coefficient between surface layers at 23 [deg.] C. and 80% RH is 0.50 or less.