JP3450211B2 - Thermocompression laminated body and method for producing the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermocompression laminated body which does not use an adhesive or a solvent in a laminating process and a method for producing the same.

[0002]

2. Description of the Related Art Increased strength, protection of printing, improvement of beauty,
It is well known that a plastic film is laminated with another plastic film or the like and used for packaging or the like for the purpose of improving the heat-sealing property and the gas barrier property. As a laminating method, a dry laminating method in which a base film is printed if necessary, an adhesive is then applied, and then a film having other characteristics is laminated is disclosed in JP-A-56-7711.
6, JP-A-56-109726, JP-A-5
A thermocompression laminating method that does not use an organic solvent in the laminating process is proposed in Japanese Patent Laid-Open No. 7-47624. Compared with the dry laminating method, the thermocompression laminating method is
Since it does not use organic solvents, it is highly environmentally friendly.
Since the drying step can be omitted during the lamination, the number of steps can be reduced, and so on.

[0003]

However, in the thermocompression bonding method proposed by each of the above-mentioned publications, even if a good quality laminate can be obtained under a certain condition, it takes a long time to perform maintenance for that purpose. Or, the allowance for obtaining a good laminate is narrow, and the quality of the laminate may vary greatly in some cases. Specifically, in the conventional thermocompression-bonding laminating method, since literally heat and pressure are applied for laminating, the obtained laminated body is deformed to cause a curl phenomenon, or causes a pattern deviation when printing is performed. , Etc. could not be solved easily. Further speaking, a method of laminating at low temperature is conceivable in order to solve the problem, but in the laminating method disclosed in each of the above publications, a film is attached to one surface of a roll nip device used as a thermocompression bonding device. However, it is extremely difficult to provide a laminate of substantially low temperature and good quality due to problems such as poor sliding between the film and the guide rolls or nip rolls of the thermocompression bonding apparatus.

In view of such circumstances, as a result of earnest studies, the present inventors have provided a method of thermocompression-bonding a plastic film or a plastic film laminate easily at a substantially low temperature, and at the same time, provide the method. The purpose is to easily improve the quality of the laminate obtained by curling, pattern distortion, slippage, etc., or to expand the allowance of the conditions for obtaining a good laminate and easily obtain a thermocompression-bonded laminate. Then, the present invention has been completed.

[0005]

As means for solving the above-mentioned problems, one of the present inventions is a plastic film (A).
Or its laminated body (A ′), and the other has a tensile fracture strength of 6
Thermocompression bonding, which is a plastic film (B) or a laminate (B ') consisting of at least two layers of kg / mm ² or less, and at least one of which has a laminating surface with a Vicat softening point of 100 ° C or less. It is a laminated body.

Further, the plastic film (B) or the laminate (B ') thereof is characterized in that the melting point of the laminated surface is lower than the melting point of the non-laminated surface by 20 ° C or more. Further, the glossiness of the non-laminated surface of the plastic film (A) or the laminate (A ') constituting the laminate is 100% or more.

Further, when the thermocompression-bonded laminate is obtained, it is characterized by including a step of laminating by a roll nip device in which the surface temperature of the heating roll is 40 to 100 ° C.

[0008]

The plastic films (A) and (B) according to the present invention are not particularly limited, and examples of the plastic film (A) include polyolefins such as polyethylene, polypropylene, polybutene and polymethylpentene, Various copolymers containing those monomer units as main components, such as 6 nylon, 6,66 nylon, 6,1
Polyamide such as 2 nylon, 12 nylon, aromatic nylon resin, amorphous nylon and the like, polyethylene terephthalate, polybutylene terephthalate and the like,
A plastic film of generally 100 μm or less including polyacrylonitrile, polycarbonate, polystyrene, polyvinyl chloride, polyvinylidene chloride and the like can be exemplified. Examples of the laminate (A ′) include those obtained by laminating the plastic film (A) exemplified above and a non-woven fabric, paper, synthetic paper, walliff, metal composite material or the like.

As the plastic film (B), for example, polypropylene, high-density polyethylene, medium-density polyethylene, low-density polyethylene, linear low-density polyethylene, polyethylene such as ultra-low-density polyethylene, polyolefin such as polybutene, polymethylpentene, etc. , Copolymers containing these monomer units as main components, for example, ethylene vinyl acetate copolymer, ethylene acrylic acid copolymer, ethylene methyl acrylate copolymer, ethylene ethyl acrylate copolymer, ethylene methacrylic acid copolymer Polymers, saponified products of ethylene-vinyl acetate copolymer, partially saponified products, ionomers, etc., or modified products thereof with maleic anhydride, 6 nylon, 6,66 nylon, 6,1
Polyamide such as 2 nylon, 12 nylon, aromatic nylon resin, amorphous nylon and the like, polyethylene terephthalate, polybutylene terephthalate and the like,
It is composed of at least two layers containing polyacrylonitrile, polycarbonate, polystyrene, polyvinyl chloride, polyvinylidene chloride and the like.

As the laminate (B '), the plastic film (B) exemplified above, a non-woven fabric, paper,
An example is a laminate of synthetic paper, wallif, and metal composite material.

The plastic film (B) or the laminate (B ') thereof has a tensile breaking strength of 6 kg / mm ² or less in at least one of the longitudinal direction and the direction perpendicular thereto.
Preferably 5 kg / mm ² or less, more preferably 4 kg
/ Mm ² or less. Tensile breaking strength is 6kg / m
If it exceeds m ² , the film becomes too hard, and it is difficult to obtain the adhesion strength or the adhesive strength during thermocompression lamination.
In addition, it tends to be difficult to obtain the desired transparency and glossiness.

Further, of the plastic film (A) or its laminate (A ') and the plastic film (B) or its laminate (B'), the material forming the surface to be laminated has a Vicat softening point of 100 °. It is desirable to have a resin of C or less, and either one of the laminated surfaces of the plastic films (A), (B) or their laminates (A ′) and (B ′), preferably both laminated surfaces. It is desirable to have a resin having a Vicat softening point of 100 ° C. or less. Further, it is preferable to have a Vicat softening point of 80 ° C. or less,
More preferably, it has a Vicat softening point of 60 ° C. or less. Vicat softening point is 100 ° C
When it exceeds, the laminated surface becomes hard, and it is difficult to obtain sufficient adhesion strength or adhesive strength after thermocompression lamination, and it is difficult to obtain good transparency and gloss. Peel strength is 50g /
It is 15 mm or more, preferably 100 g / 15 mm or more, more preferably 180 g / 15 mm or more.

As a material having a Vicat softening point of 100 ° C. or less for forming a laminated surface, for example, a vinyl acetate content is about 3 to 50 wt%, preferably 15 to 48 wt.
%, More preferably 19 to 47 wt% ethylene vinyl acetate copolymer, acrylic acid content of about 2 to 25 wt%, preferably 5 to 20 wt% ethylene acrylic acid copolymer, and methyl acrylate content of 3 to 40 wt%
Degree, preferably 15-35 wt% ethylene methyl acrylate copolymer, methacrylic acid content 2-30 wt%
Ethylene methacrylic acid copolymer of about 8 to 15 wt%, ethyl acrylate content of about 3 to 40 wt%, preferably 15 to 35 wt% of ethylene ethyl acrylate copolymer, butene of butene content of 40 wt% or more Examples thereof include (co) polymers, ionomers having a methacrylic acid content of about 2 to 30 wt%, preferably 3 to 15 wt%, and modified products thereof.

By specifying the plastic film (A), the laminated body (A '), the plastic film (B) and the laminated body (B') as described above, it becomes possible to laminate at a low temperature, so that the curling phenomenon occurs. It is possible to easily obtain a high-quality laminated body in which a pattern does not occur when printing is performed.

In the material forming the laminate surface, a lubricant, a lubricant, etc. are taken into consideration in consideration of workability and workability before lamination.
An antiblocking agent, an antistatic agent, an antioxidant, a deodorant, etc. may be contained. As the lubricant, fatty acid, fatty acid metal salt, silicone oil, waxes, stearic acid amide, oleic acid amide, palmitic acid amide,
Fatty acid amides such as erucic acid amide and behenic acid amide, ethylene bis fatty acid amides, their derivatives,
Examples thereof include modified products thereof. The dynamic friction coefficient of the laminated surface is 0.05 to 2.0, preferably 0.1 to 2.0.
It is desirable to be in the range of 1.5, more preferably 0.15 to 1.0. If the coefficient of kinetic friction is less than 0.05, there is a tendency for slippage and slippage when the film is wound long,
If it exceeds 2.0, the slipperiness is so poor that wrinkles may occur when the film is wound in a long length, it may be difficult for the film to pass through when it is applied to a thermocompression laminating apparatus, or scratches may easily occur.

As the antiblocking agent, inorganic particles such as silica, talc, feldspar, calcium carbonate, titanium oxide, magnesium hydroxide, aluminum hydroxide, calcium hydroxide, aluminosilicate, clay, kaolin and glass, or polymethacryl. Examples thereof include methyl acid copolymers, organic particles such as urea resins, and fatty acid coated products thereof. As the antistatic agent, fatty acid esters such as glycerin fatty acid ester and sorbitan fatty acid ester, condensation products of fatty acid and diethanolamine, N, N bisaliphatic amine, or derivatives thereof, alkyl sulfonates Etc. can be illustrated.

Aging treatment may be carried out after the thermocompression-bonding lamination in order to promote migration of the above-mentioned various additives to the surface of the thermocompression-bonding laminate and to further impart dimensional stability of the thermocompression-bonding laminate. The aging conditions may be appropriately selected depending on the film material, the type of additives and the like. Aging is preferably carried out at 25 to 45 ° C for 5 to 24 hours.

Plastic film (B) in the case of thermocompression lamination for the purpose of imparting heat sealability
As a uniaxially stretched film rather than a biaxially stretched film,
More preferably, it is a non-stretched film. In addition, when the laminate is used as a package and sufficient heat sealing strength is required, an adhesive layer may be provided between the layer forming the laminated surface and the layer forming the non-laminated surface depending on the material. Good. When used as a package, it has a sufficient heat seal strength of 500.
g / 15 mm or more, preferably 1000 g / 15 mm or more, more preferably 2000 g / 15 mm or more.

If necessary, the surfaces of the plastic films (A) and (B) and the laminates (A ') and (B') to be laminated may be in air, nitrogen, helium, argon, etc. Surface treatment such as corona discharge treatment in active gas, plasma treatment, flame treatment, acid treatment, and sandblast treatment may be performed. Particularly, when the plastic film (A) or the laminate (A ') thereof is printed, the plastic film (A), (B) or the laminate (A'), (B ') thereof is laminated. The surface is
By the above surface treatment and the like, the wetting index is 35 to 75 dyn.
It is desirable that it is e / cm, preferably 40 to 70 dyne / cm. If it is less than 35 dyne / cm, it tends to be difficult to obtain the adhesive strength at the time of thermocompression bonding with the printed portion of the plastic film (A), especially on the laminated surface of the plastic film (B), and 75 dyn
If it exceeds e / cm, the film becomes more sticky,
Workability before lamination tends to be poor.

On the laminated surface of the plastic film (A) or the laminate (A ') thereof, for example, toluene, IP
Printing may be performed using ink using an organic solvent such as A (isopropanol) or ethyl acetate as a solvent, or ink using water or a mixture of alcohol and water as a solvent. According to the present invention, a pattern deviation does not occur, which is more preferable.

The melting point (hereinafter referred to as mp1) of the material forming the laminated surface of the plastic film (B) or the laminate (B ') thereof is higher than the melting point of the material forming the layer on the non-laminated surface (hereinafter referred to as mp2). It is desirable that the structure be lower than 20 ° C. The melting point of each layer refers to the melting peak temperature measured by a differential scanning calorimeter (DSC) according to JIS K 7121, which is heated at 10 ° C./min. When a plurality of melting peak temperatures are obtained, The minimum value for mp1 and the maximum value for mp2 are the melting points of the layers. The difference between the melting points is preferably 20 ° C. or higher, more preferably 30 ° C. or higher, further preferably 40 ° C. or higher, most preferably 60 ° C. or higher. If it is less than 20 ° C, stickiness and deterioration of slipperiness are likely to occur after thermocompression bonding, and it tends to be very difficult to handle as a laminate. Further, as the layer on the non-laminated surface, a layer on the surface opposite to the laminated surface (the surface to be laminated) can be exemplified.

The roll nip device according to the present invention is not particularly limited, and a known method may be used, but a method of nipping a heated metal roll and a rubber roll is simple and preferable. The nip pressure is a linear pressure of 5 to 300 kg /
cm, preferably 10 to 150 kg / cm, more preferably 15 to 100 kg / cm. If it is less than 5 kg / cm, good adhesiveness and adhesive strength may not be obtained in some cases, and if it exceeds 300 kg / cm, the rubber roll tends to be severely worn and becomes unpractical. Further, in order to further increase the laminating speed, preheating of the film by contact with another roll in front of the roll nip device, preheating by taking a long contact time of the film with the metal roll of the roll nip device, infrared heating, etc. Preheating by non-contact heating may be applied. The laminating speed is usually about 10 to 200 m / min, but is not particularly limited thereto.

Regarding the heating method, a method of heating from the side of the plastic film (A) or the laminate (A ') thereof,
A method of heating from the side of the plastic film (B) or its laminate (B ') or a method of heating from both sides is conceivable, but from the gist of the present invention, the plastic film (B) or its laminate (B'). A method of heating from the side is more preferable.

The heating roll for substantially thermocompression bonding according to the present invention literally means that the laminate is not thermocompression bonded before passing through the roll nip device, and the laminate is thermocompression bonded after passing through the roll nip device. Alternatively, the surface temperature of the roll is preferably 40 to 100 ° C, more preferably 45 to 90 ° C, further preferably 50 to 80 ° C, most preferably 55 to 75 ° C. It is C. If it exceeds 100 ° C, problems such as deterioration of lubricity due to thermal deformation of the film tend to occur, and if it is less than 40 ° C, sufficient adhesive strength tends not to be obtained. In order to produce a laminate of good quality, the laminating speed, thermocompression roll nip pressure, film tension before and after laminating may be appropriately selected depending on the roll temperature.

Among the non-laminated surfaces of the plastic film (A) or the laminate (A ') forming the laminate according to the present invention, the glossiness of the non-printed portion is such that the appearance and the appearance of the laminate are beautiful. 10 to create a feeling
It is preferably 0% or more. More preferably 120
% Or more, more preferably 140% or more. Lamination speed, laminating temperature, and nip roll pressure may be appropriately selected to obtain a gloss value of a certain value or more, but according to the present invention, since the laminating surface has a low softening point,
It can be said that, as compared with the conventional thermocompression-bonding laminating method, a glossy feeling is easily expressed, and thus a laminate having a high glossiness is easily obtained.

[0026]

EXAMPLES The present invention will be specifically described below with reference to Examples and Comparative Examples.

The measurement of each physical property value and the evaluation of the pattern deviation and the transparency of the plain portion are as follows.

The tensile fracture strength of the plastic film (B) or its laminate (B ') is measured in accordance with JIS K-7127, and the smaller one of the longitudinal direction of the film and the direction orthogonal thereto is tensile fracture. It was strength.

The Vicat softening point is determined according to JIS K 7206 based on the materials constituting the laminated surfaces of the plastic film (A), the laminate (A '), the plastic film (B) and the laminate (B'). The test load was measured by the A method.

The melting point (mp) of the material constituting the laminating surface of the plastic film (B) and its laminate (B ')
1) and the melting point of the material that constitutes the non-laminated surface (mp2)
Is as follows. That is, the melting point is in accordance with JIS K 7121, the temperature is raised at 10 ° C / min, and the differential scanning calorimeter (DS) is used.
It refers to the melting peak temperature measured in C), and when a plurality of melting peak temperatures are obtained, the minimum value for mp1 and the maximum value for mp2 were taken as the melting point of the layer.

The glossiness of the non-laminated surface of the plastic film (A) or its laminate (A ′) is the opposite of the laminated surface of the plastic film (A) or its laminate (A ′) forming the laminate. The glossiness of the unprinted part of the surface is measured.
According to S Z 8741, the incident angle and the light receiving angle were measured at 45 degrees.

The thermocompression bonding strength of the plain part is 20
It was measured by peeling in the direction of 180 degrees at 0 mm / min.

The dynamic friction coefficient of the non-laminated surface of the film (B) after lamination was measured according to ASTM D-1894.

The heat-sealing strength between the laminated films (B) was 130 ° C., 2 kg / cm ² , and the test piece heat-sealed at 1 second was 1 at a tensile speed of 200 mm / min.
Measured by peeling in the direction of 80 degrees

The evaluation of the pattern deviation and the transparency of the plain portion is done visually.

Example 1 Propylene homopolymer (MF
R 3), melting point 138 ° C, Vicat softening point 12
A propylene-ethylene copolymer (MFR 8) having an ethylene content of 3.8 wt% at 3 ° C was layered and coextruded from a T-die at 230 ° C, and then roll-stretched at a temperature of 120 ° C by a factor of 5 in the longitudinal direction. At 150 ° C, tenter stretching was carried out in the direction perpendicular to that, and the propylene homopolymer layer was 20 μm.
m, propylene-ethylene copolymer layer 2 μm, total thickness 22
A biaxially oriented polypropylene film A-1 having a thickness of μm was obtained. On the other hand, an ethylene vinyl acetate copolymer having a vinyl acetate content of 32 wt%, a melting point of 66 ° C and a Vicat softening point of 35 ° C (M
FR 30), melting point 138 ° C, Vicat softening point 1
A propylene-ethylene copolymer (MFR 8) having an ethylene content of 3.8 wt% at 23 ° C. was used by using two extruders.
Laminate coextrusion was performed from a T die at 80 ° C. to obtain a film B-1 having an ethylene vinyl acetate copolymer layer of 4 μm, a propylene ethylene copolymer layer of 36 μm and a total thickness of 40 μm.
In order to improve workability, 0.3 wt% of silica as a blocking inhibitor and 0.3% of erucic acid amide as a lubricant were added to Film B-1 before extrusion. Film A-1, propylene ethylene copolymer surface and film B
The ethylene vinyl acetate copolymer surface of No. 1 was used as a laminate surface, and the film was placed so that the film B-1 was in contact with the heating metal roll. The surface temperature of the heating metal roll was 70 ° C., the laminating speed was 120 m / min, and the thermocompression roll nip pressure ( Linear pressure) 40
Lamination was performed at kg / cm to obtain a laminated body 1.

(Example 2) 70% water and ethyl alcohol 3 on the propylene-ethylene copolymer surface of A-1 of Example 1
An ink using a mixture with 0% as a solvent was printed and dried so that the printed area was about 40% of the total area to obtain a film A-2. Further, a film B-2 was obtained in the same manner as in Example 1 except that the surface of the ethylene-vinyl acetate copolymer of B-1 of Example 1 was subjected to corona discharge treatment in air at 30 W · min / m ² .
Then, a laminate 2 was obtained in the same manner as in Example 1.

Example 3 The surface of the ethylene-vinyl acetate copolymer of B-1 of Example 1 was coated with a nitrogen concentration of 9 at 30 W · min / m ^2.
Example 2 except that corona discharge treatment was performed under 8 vol%
A film B-3 was obtained in the same manner as in, and then a laminate 3 was obtained in the same manner as in Example 2.

(Example 4) A biaxially stretched polyethylene terephthalate film (Emblet PET manufactured by Unitika Ltd.) having a thickness of 12 μm was used as A-4 in place of the biaxially stretched polypropylene film of Example 3, and the same as in Example 3. Instead of the ethylene vinyl acetate copolymer, an ethylene methyl acrylate copolymer (MFR 20) having a methyl acrylate content of 20 wt%, a melting point of 80 ° C., and a Vicat softening point of 59 ° C. was used, and B-3 of Example 3 was used. Instead of the propylene-ethylene copolymer, the melting point is 106 ° C and the Vicat softening point is 8
A film B-4 was obtained in the same manner as in Example 3 except that low density polyethylene (MFR 8) at 2 ° C was used, and then a laminate 4 was obtained in the same manner as in Example 3.

Example 5 Example 4 was repeated except that the biaxially stretched polyethylene terephthalate film of Example 4 was replaced with a biaxially stretched 6-nylon film having a thickness of 15 μ (Emblem ON manufactured by Unitika Ltd.) as A-5. As well as
A laminate 5 was obtained in the same manner as in Example 4.

Example 6 Instead of the ethylene-vinyl acetate copolymer of Example 1, the melting point was 48 ° C. and the Vicat softening point was 3.
An ethylene vinyl acetate copolymer (MFR 6) having a vinyl acetate content of 46 wt% at 5 ° C or less is used, a laminating temperature is 55 ° C, a laminating speed is 40 m / min, and a thermocompression roll nip pressure (linear pressure) is 15 kg / cm. A film B-6 was obtained in the same manner as in Example 1 except for the above, and then a laminate 6 was obtained in the same manner as in Example 1.

(Comparative Example 1) The propylene ethylene copolymer monolayer of Example 1 was used in place of the two-layer laminate of the ethylene vinyl acetate copolymer and propylene ethylene copolymer of Example 1. Was performed in the same manner as in Example 1 to obtain a laminate 1 '.

Comparative Example 2 The ethylene vinyl acetate copolymer single layer of Example 1 was used in place of the two-layer laminate of the ethylene vinyl acetate copolymer and propylene ethylene copolymer of Example 1. A laminate 2'was obtained in the same manner as in Example 1 except for the above.

(Comparative Example 3) A propylene homopolymer (MFR 3) having a melting point of 166 ° C was used in place of the two-layer laminate of the ethylene-vinyl acetate copolymer and the propylene-ethylene copolymer of Example 1. After coextrusion with the ethylene-vinyl acetate copolymer of Example 1, the film was stretched in the same manner as in Example 1 to give a propylene homopolymer layer of 36 μm, an ethylene-vinyl acetate copolymer layer of 4 μm, and a total thickness of 40 μm. A laminate 3'was prepared in the same manner as in Example 1 except that B-3 'was prepared and the surface of the ethylene-vinyl acetate copolymer of B-3' was used as the laminate surface.

The physical properties and evaluation of each of the obtained laminates are as shown in the table below.

[0046]

EFFECTS OF THE INVENTION According to the present invention, it is possible to easily improve the beauty of a thermocompression-bonded laminate or to improve workability in a step after lamination, and to obtain a good laminate in a thermocompression-bonding laminating method. Since the allowance of the condition can be expanded, it becomes possible to perform thermocompression lamination without applying an adhesive in the laminating process even with a relatively simple conventional dry laminating machine or the like, and by the further spread of thermocompression lamination, It is considered to be very useful for solving various environmental problems.

─────────────────────────────────────────────────── --Continued from the front page (56) References JP-A-6-155579 (JP, A) JP-A-56-109726 (JP, A) JP-A-56-77116 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) B32B 1/00-35/00 B29C 63/00-65/82

Claims (4)

(57) [Claims] 1. A thermocompression-bonded laminate, one of which is a plastic film (A) or a laminate thereof (A '), and the other is a plastic film (B) having a tensile breaking strength of 6 kg / mm ² or less. ) Or a laminate (B ′) thereof, and at least one of them has a laminating surface having a Vicat softening point of 100 ° C. or less. 2. The thermocompression-bonded laminate according to claim 1, wherein the plastic film (B) or the laminate (B ′) thereof has a constitution in which the melting point of the laminating surface is lower than the melting point of the non-laminating surface by 20 ° C. or more. body. 3. The thermocompression-bonded laminate according to claim 1, wherein the non-laminated surface of the plastic film (A) or the laminate (A ′) has a glossiness of 100% or more. 4. The surface temperature of the heating roll is 40 to 100 ° C.
The method for producing a thermocompression-bonded laminate according to any one of claims 1 to 3, comprising a step of laminating with a roll nip device.