JP5284862B2 - Film and manufacturing method thereof - Google Patents

Description

The present invention relates to a film having excellent hand cutting properties and straight line cutting properties and a method for producing the same.

As a method of imparting properties (hand-cutting properties) that allow the film to be cut by hand without using scissors or a cutter, a method of blending an additive such as a filler into the material constituting the film (for example, a patent) Document 1) and methods for making holes and scratches on films (for example, Patent Documents 2 and 3) are known. In addition, as a method of imparting a property (straight cut property) that allows the film to be cut in a straight line, a method of stretching the film and aligning its molecular orientation in one direction (for example, Patent Document 4), or a material of the film There is known a method (for example, Patent Document 5) in which different materials are blended when blended to form a sea-island structure, and this is used as a film and then stretched to give anisotropy.

JP 2002-52843 A Japanese Patent No. 2716352 Japanese Patent No. 2805343 Japanese Patent No. 2936688 JP 2007-100000 A

This invention makes it a subject to provide the film excellent in hand cutting property and linear cut property, and its manufacturing method.

That is, the present invention relates to a JIS for unevenness in the MD direction , characterized in that an uneven shape shaping plate attached to an ultrasonic transmitter of an ultrasonic vibration facility is pressed against the surface of the film to give the surface of the film unevenness. This is a method for producing a film in which the average value of the local peak-to-peak distance defined by B 0601 is 8 μm or less.

In the present invention, the “average value of the local peak interval” is used as a parameter indicating the degree of roughness of the film surface. The average value of the local summit interval is measured by a method based on JIS B 0601. In other words, from the roughness curve, the reference length l is extracted in the direction of the average line, the length of the average line corresponding to the interval between adjacent local peaks is obtained, and the average value of the numerous local peak intervals is expressed. is there. Here, the local summit means the top of the convex portion in the roughness curve, and indicates the point where the slope of the tangent of the roughness curve reverses from positive to negative. In the actual analysis, the point where the differential value of the roughness curve reverses from positive to negative is the local peak. The average value of the local summit interval is usually expressed in millimeters (mm), but in the present invention, it is expressed in micrometers (μm). In the present invention, the “difference in the average value of local peak intervals” means the absolute value of the difference between the average value of the local peak intervals in the MD direction and the average value of the local peak intervals in the TD direction. .

ADVANTAGE OF THE INVENTION According to this invention, the film excellent in hand cutting property and linear cut property, and its manufacturing method are obtained.

The schematic diagram showing the state which looked at the one aspect | mode of the uneven | corrugated shaped board from the horizontal direction. The schematic diagram showing the state which looked at the uneven | corrugated shaped board in FIG. 1 from the front. The schematic diagram showing the state which looked at the other aspect of the uneven | corrugated shaped board from the horizontal direction. The schematic diagram showing the state which looked at the uneven | corrugated shaped board in FIG. 3 from the front. The schematic diagram showing the jig used for evaluation of hand cutting property in an Example.

Hereinafter, preferred embodiments for carrying out the present invention will be described. In addition, embodiment described below shows an example of typical embodiment of this invention, and, thereby, the range of this invention is not interpreted narrowly.

The film has an average value of the local peak-to-peak distance defined by JIS B 0601 of irregularities in the MD direction of 8 μm or less. In addition, when the film which concerns on this invention is contained in the intermediate | middle layer of a laminated body, the surface of a film shall mean the surface before lamination | stacking.

The average value of the local peak-to-peak distance of the film is preferably 8 μm or less, more preferably 7 μm or less, and further preferably 6 μm or less in the MD direction (the flow direction of the resin when the film is produced). By setting the average value of the local peak-to-peak distance within this numerical range, the stress concentration field increases in the case of hand cutting, so that excellent film hand cutting performance in the MD direction can be obtained. On the other hand, if the average value of the local summit spacing exceeds 8 μm, the stress concentration field is reduced during hand cutting, so the hand cutting property is deteriorated.

Furthermore, the average value of the local summit spacing in the MD direction is preferably 2 μm or more, and the difference between the average value of the local summit spacing in the MD direction and the average value of the local summit spacing in the TD direction (direction orthogonal to the MD direction on the film plane) is 2 μm or more. Is preferably 10 μm or more, more preferably 20 μm or more. By making the average value of the local peak interval in two orthogonal directions within this numerical range, stress is concentrated in the direction where the average value of the local peak interval is small, so that anisotropy can be imparted to the hand cutting property. An excellent linear cut property of the film in the direction can be obtained.

The average value of the local summit interval can be calculated from the roughness curve of the film surface by a method based on JIS B 0601. The roughness curve can be measured by a conventionally known method. For example, the roughness curve is measured by observing the film with an ultradeep shape measuring microscope using laser light. In this ultra-deep shape measurement microscope, a film sample can be directly observed by using laser light, and a roughness curve can be analyzed by measuring a three-dimensional shape from a surface shape with severe irregularities.

In the present invention, the term “film” means a thin object having an extremely small thickness compared to the surface, and the film according to the present invention includes so-called “sheet” and “web”. . Films and sheets are usually distinguished by thickness, and a thin one is called a film and a thick one is called a sheet. The web is particularly flexible and has a length that is extremely long compared to the width. Further, the film may be not only a single layer but also a laminate in which a plurality of types of films are laminated. The laminate is a laminate of film, sheet, paper, aluminum or other metal foil, etc., laminated by wet lamination, dry lamination, solventless lamination, extrusion lamination, thermal lamination or the like.

The material of the film is not particularly limited. For example, low density polyethylene, medium density polyethylene, high density polyethylene, linear low density polyethylene, ethylene-α-olefin copolymer, polypropylene (homopolymer, random) At least one polyolefin resin selected from propylene-α-olefin copolymer, ethylene-vinyl acetate copolymer, and the like; polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate Polyester resins such as: polyamide resins, polyvinyl chloride resins, vinylidene chloride resins, polystyrene resins, methacrylic resins, polyvinyl alcohol resins, polyvinylidene chloride or copolymers thereof, polyvinylidene fluoride resins and polyvinylidene fluoride There is a mixture of resin and PMMA resin, cellophane and the like. Among these, a polyolefin resin is preferable, and a polyethylene resin is particularly preferably used. These resins may be used alone or in combination of two or more.

The film before imparting irregularities to the surface can be obtained, for example, by molding a resin extruded from a T-die into a sheet shape. In addition to this, various molding methods such as a calendering method, a casting method, an inflation method, a solution casting method, and a method of applying and molding after dissolving in a solvent can be used. The film obtained by such a method has irregularities on its surface. The average value of the local peak-to-peak distance in any one direction of the unevenness varies depending on the material forming the film and the manufacturing method thereof, but is generally 10 to 50 μm.

The storage elastic modulus of the film is preferably in the range of 1 × 10 ⁸ to 10 ¹⁰ Pa, preferably 1.5 × 10 ^{8 to} 7.5 × 10 ⁹ Pa, more preferably 2 × 10 ^{8 to} 5 × 10 ⁹ Pa. . A film having a storage elastic modulus in this range has good formability without sticking to a concavo-convex shaped plate when imparting concavo-convex to the surface thereof.

Here, the storage elastic modulus of the film is a measure of energy that reflects the characteristics of the film as elasticity and stores the applied stress to be completely recovered.

In order to give unevenness to the surface of the film, for example, an uneven shape shaping plate having an ultrasonic transmitter of ultrasonic vibration equipment attached thereto may be pressed against the surface of the film. It is preferable to adjust the ultrasonic vibration to a range of 10 to 100 kHz because the unevenness of the film can be shaped efficiently.
As the concavo-convex shaped plate, for example, a single blade as shown in FIGS. 1 and 2 or a multiple blade as shown in FIGS. 3 and 4 can be used. Moreover, the uneven | corrugated shaped board can also make the front-end | tip into a saw blade shape.

A triangular shape is effective for the cross-sectional shape of the blade of the irregular shaped plate. Also, the sharper the angle, the more effective. The angle of the blade of the irregular shaped plate is not particularly limited, but a range of 10 to 60 ° is preferable, and a range of 10 to 45 ° is particularly preferable.

The average value of the local peak-to-peak spacing of the unevenness can be arbitrarily adjusted by adjusting the timing of pressing the uneven shaping plate against the film (frequency of the ultrasonic transmitter) and the line speed of the film. Further, the deeper the unevenness, the better the concentration of stress.

The area occupied by the region where irregularities are shaped on the film surface can be in the range of 1 to 100%, preferably 5 to 100% of the film surface area. Here, 1% of the film surface area is a state in which an uneven pattern is formed in an area of 1% on the film. Moreover, 100% is a state in which a concavo-convex pattern is formed on the entire film.

Concavo-convex shaping is not limited to a film-like shape, and can also be performed on a part of back-sticking such as pillow packaging.

A film having irregularities and a laminate using the film can be formed into a pressure-sensitive adhesive tape by laminating a pressure-sensitive adhesive layer or a hot melt adhesive layer on at least one surface thereof. As the pressure-sensitive adhesive, those generally used can be appropriately used. For example, a rubber-based pressure-sensitive adhesive, an acrylic pressure-sensitive adhesive, a silicone-based pressure-sensitive adhesive, a urethane-based pressure-sensitive adhesive, and the like can be used. Moreover, in order to make these adhesives have desirable performance, a tackifier, an anti-aging agent and a curing agent can be blended.

The means for applying the pressure-sensitive adhesive is not particularly limited, and for example, a gravure roll coater, reverse roll coater, kiss roll coater, dip roll coater, bar coater, knife coater, and spray coater can be used. The thickness of the adhesive layer after drying is preferably in the range of 10 to 80 μm, more preferably 15 to 65 μm. If it is less than 10 micrometers, the adhesive force of the adhesive tape obtained may become low. On the other hand, if the thickness exceeds 80 μm, the pressure-sensitive adhesive is thickly applied more than necessary, and the cost is wasted.

EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, it is not limited to this.

Example 1
An uneven shaped plate having 10 blades installed at intervals of 5 μm is attached to an ultrasonic vibrator of an ultrasonic vibration welder (AGM manufactured by rinco), vibrated at 35 kHz, and polyethylene manufactured by Tamapoly at a line speed of 100 m / min. A film (trade name: LC-2, thickness 50 μm, storage elastic modulus: 3.3 × 10 ⁸ ) was passed through. At this time, adjustment was made so that the tip of the uneven shaping plate was in contact with the film with a pressure of 6 MPa, and unevenness was formed on the surface of the film. The average value of the local peak-to-peak distance in the MD direction of the obtained film was 5.3 μm, and the average value of the local peak-to-peak distance in the TD direction was 25.5 μm.
In addition, the storage elastic modulus of the film was measured by a method according to JISK-7244 (tensile mode, frequency 1 Hz, distance between chucks 5 mm, measurement temperature 40 ° C.) using DMS6100 manufactured by Seiko Instruments Inc.
In addition, the average value of the local summit interval was measured under the following conditions using an ultra-deep shape measurement microscope VK-8510: VK shape analysis application software: version 1.06 manufactured by Keyence Corporation, and a measured value of n = 3 or more. The average value was shown.
(A) Magnification: 1000x (20x50x lens)
(B) Microscope observation conditions (gain: 645, offset: 1569, pitch: 0.01 μm)
(C) Observation scale: 550 μm × 550 μm

(Example 2)
The concavo-convex shaped plate was changed to one provided with 6 blades at intervals of 8 μm, and the concavo-convex shape was formed on the film in the same manner as in Example 1. The average value of the local peak-to-peak distance in the MD direction of the obtained film was 7.9 μm, and the average value of the local peak-to-peak distance in the TD direction was 27.8 μm.

(Example 3)
A biaxially stretched polypropylene film (trade name: Pyrene-OT P4748, thickness 40 μm, storage elastic modulus: 8.8 × 10 ⁸ ) manufactured by Toyobo Co., Ltd. was used as the film before uneven forming, and the same as in Example 1. To obtain a film. The average value of the local peak-to-peak distance in the MD direction of the obtained film was 5.1 μm, and the average value of the local peak-to-peak distance in the TD direction was 27.6 μm.

Example 4
A biaxially stretched polypropylene film (trade name: Pyrene-OT P4748, thickness 40 μm, storage elastic modulus: 8.8 × 10 ⁸ ) manufactured by Toyobo Co., Ltd. was used as the film before uneven forming, and the same as in Example 2. To obtain a film. The average value of the local peak-to-peak distance in the MD direction of the obtained film was 7.7 μm, and the average value of the local peak-to-peak distance in the TD direction was 29.8 μm.

(Example 5)
A nylon film (trade name: emblem ON, thickness 25 μm, storage elastic modulus: 4.2 × 10 ⁹ ) manufactured by Unitika Co., Ltd. was used as the film before uneven forming, and a film was obtained in the same manner as in Example 1. The average value of the local peak-to-peak distance in the MD direction of the obtained film was 5.3 μm, and the average value of the local peak-to-peak distance in the TD direction was 29.6 μm.

(Example 6)
A nylon film (trade name: emblem ON, thickness 25 μm, storage elastic modulus: 4.2 × 10 ⁹ ) manufactured by Unitika Co., Ltd. was used as the film before uneven forming, and a film was obtained in the same manner as in Example 2. The average value of the local peak-to-peak distance in the MD direction of the obtained film was 7.6 μm, and the average value of the local peak-to-peak distance in the TD direction was 31.8 μm.

(Example 7)
As a film before uneven forming, a PET film (trade name: Emblet PC, thickness 12 μm, storage modulus: 2.8 × 10 ⁹ ) manufactured by Unitika Co., Ltd. was used, and a film was obtained in the same manner as in Example 1. . The average value of the local peak-to-peak distance in the MD direction of the obtained film was 5.2 μm, and the average value of the local peak-to-peak distance in the TSD direction was 35.1 μm.

(Example 8)
As a film before uneven forming, a PET film (trade name: Emblet PC, thickness 12 μm, storage elastic modulus: 2.8 × 10 ⁹ ) manufactured by Unitika Co., Ltd. was used, and a film was obtained in the same manner as in Example 2. . The average value of the local peak-to-peak distance in the MD direction of the obtained film was 7.5 μm, and the average value of the local peak-to-peak distance in the TD direction was 37.3 μm.

(Comparative Examples 1-4)
A film was obtained in the same manner as in Example 1 except for the film, storage elastic modulus, line speed, frequency, and number of irregularities shown in Table 3.

Comparative Example 5
In Example 1, the film was processed by operating an ultrasonic vibrator at 5 kHz. Unevenness was not formed on the film surface, and the resulting film was not easily cut.

Comparative Example 6
In Example 1, the film was processed by operating an ultrasonic vibrator at 100 kHz. Due to the heat generated by friction between the film and the concavo-convex shaped plate, the formed concavo-convex shape did not become sharp, and the resulting film was poorly cut.

Evaluation of hand-cutting is performed in an evaluation test chamber set at a temperature of 23 ± 2 ° C. and a humidity of 50 ± 5% RH, with a hardness of HDA70 measured by the durometer hardness test method in JISK7215 on the jig of FIG. A test was performed using a rubber-equipped one. The film is cut into 100 mm squares, gripped by 20 mm in the cutting direction and the interval of the jig being 15 mm, and teared at a speed of 500 mm / min with a tensile tester (manufactured by Shimadzu Corporation, model name: Autograph AGS-500A). The strength at break was measured, and the average value of the measured values of n = 3 or more was shown.
Excellent: Tensile rupture strength is less than 50 MPa Good: Tensile rupture strength is 50 MPa or more and less than 60 MPa Possible: Tensile rupture strength is 60 MPa or more and less than 70 MPa Defective: Tensile rupture strength is 70 MPa or more

The evaluation of the straight-line cutability is made by visually determining the tearing state when the film to be tested is torn in an evaluation test chamber set at a temperature of 23 ± 2 ° C. and a humidity of 50 ± 5% RH. Evaluation was based on the evaluation criteria.
Good: Possible to cut almost straight with respect to the tearing direction: Defective cutting with deviation from the tearing direction: Broken with almost no linearity

The web by the processing method of the present invention can be suitably used for food packaging, heavy bags such as asphalt and tea bags, and adhesive tape substrates.

S Test film D Jig

Claims (5)

It is specified in JIS B 0601 for unevenness in the MD direction, which is characterized in that an uneven shape shaping plate attached to an ultrasonic transmitter of an ultrasonic vibration equipment is pressed against the surface of the film to give unevenness to the surface of the film. The manufacturing method of the film whose average value of the local peak summit distance is 8 micrometers or less. The average value of the local peak-to-peak distance of the unevenness in the MD direction, wherein the uneven shaping plate attached to the ultrasonic transmitter of the ultrasonic vibration equipment is pressed against the surface of the film to give the surface of the film unevenness The method for producing a film according to claim 1, wherein the difference between the average values of the local peak-to-peak intervals of the unevenness in the TD direction is 2 μm or more.
A laminate using the film according to claim 1. An adhesive tape obtained by laminating an adhesive layer on at least one surface of the film according to claim 1. The adhesive tape obtained by laminating | stacking an adhesive layer on the at least one surface of the laminated body of Claim 3.

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