JP3806996B2 - LAMINATED FILM, ITS MANUFACTURING METHOD, AND ITS MANUFACTURING DEVICE - Google Patents

Description

【００５３】
＜比較結果＞
表１から判るように、本発明によれば、外観上の問題の全くない綺麗なラミネートフィルムができるとともに、ラミネート強度、ヒートシール強度も問題なかった。これに対して、比較例の積層フィルムには、気泡の発生が目立ち、外観不良が確認され、それに起因するラミネート強度低下が認められた。
【００５４】
【表１】

【００５５】
【発明の効果】
以上説明しように、本発明によれば、一方のフィルムにコーティングした無溶剤型接着剤層を、塗布ユニットから圧着ロール間に設けられた加熱手段により加熱して該接着剤層を平滑化処理することにより、接着剤近傍に混入したエアーにより発生する気泡を除去して他方のフィルムとラミネートしており、高速塗工で顕在化してくる接着剤塗工時の接着剤層内部およびフィルムと接着剤層との界面へのエアーの混入に起因する気泡を除去し、外観不良やラミネート強度低下を改善できる効果がある。
【図面の簡単な説明】
【図１】本発明の積層フィルムの一例を示す側断面図。
【図２】本発明の積層フィルムの製造方法、及びその製造装置を説明する概要全体側面図。
【符号の説明】
Ａ…一方のフィルム Ｂ…無溶剤型接着剤層 Ｃ…他方のフィルム
Ｄ…積層フィルム ｂ1 …フィルムＡ側の平滑面 ｂ2 …フィルムＢ側の平滑面
１…巻出部 ２…インフィードロール ３…接着剤塗布ユニット ４…接着剤
５…加熱ユニット ６…巻出部 ７…圧着ロールユニット
８…電子線若しくは紫外線照射ユニット ９…アウトフィードロール
１０…巻取部[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a laminated film laminated and laminated using a solventless adhesive that is cured by electron beam or ultraviolet irradiation, a method for producing the laminated film, and an apparatus for producing the laminated film.
[0002]
[Prior art]
Conventionally, laminated films used as flexible packaging films for foods, pharmaceuticals and the like include laminated films laminated with a solventless adhesive, and a method for producing the laminated film is also widely known. .
[0003]
The production of this laminated film consists of a plurality of rolls that contain no solvent at all and are heated to a temperature of about 80 to 100 ° C. and a viscosity of about 800 to 1300 cps at room temperature. The film is transferred to a base film by a coating unit, and immediately after that, the film is laminated with another film and passed through a pair of pressure-bonding rolls. Curing of the adhesive is completed in ~ 3 days.
[0004]
Such solvent-free adhesives are mainly polyurethane-based adhesives, and water vapor in the air is involved in the curing of the adhesive, and carbon dioxide is generated with the curing.
[0005]
Laminating methods for laminating and bonding using such solvent-free adhesives do not require an oven for drying the solvent or apply adhesives, compared to dry laminating methods using known solvent-soluble adhesives. There are merits such as a small amount, and there are many merits such as there is no concern about the flame without the residual solvent of the finished laminate product, and there is no pollution problem concerning the discharged solvent.
[0006]
Further, regarding the laminate processability, it is possible to achieve high productivity such that processing can be performed twice to three times faster than the known dry laminating method.
[0007]
Recently, an attempt has been made to use, for a solventless laminate, an adhesive that is cured by irradiation with an electron beam or ultraviolet rays from a polyurethane adhesive.
[0008]
In general, laminating with a solvent-free adhesive was completed at the time of laminating by laminating air when laminating the film at a relatively high speed, when applying the adhesive with a coating unit or when laminating with a pressure roll. There were problems such as the appearance of the film being whitened and appearance defects such as rainbow patterns.
[0009]
[Problems to be solved by the invention]
In order to solve these problems, optimization of processing conditions such as lowering the viscosity of the adhesive and improving the adhesive itself, such as improving the leveling, and optimizing the pressure and temperature of the pressure roll By trying to eliminate the appearance defect. In particular, when the adhesive is instantaneously cured, such as an electron beam or an ultraviolet curing type, the above-mentioned appearance problem becomes a very large problem.
[0010]
Therefore, the present invention provides a method and an apparatus for solving the above problems.
[0011]
[Means for Solving the Problems]
The first invention of the present invention is through one film A and a solventless adhesive layer B formed on the film A by using a solventless adhesive that is cured with an electron beam or ultraviolet rays. The film A and the film C are formed of the other laminated film C. The film A and the film C are made of the solvent-free adhesive layer B that has been smoothed by being softened by heat softening after being coated on the film A. The film A side smooth surface b1 is laminated and bonded through the film C side smooth surface b2 of the solventless adhesive layer B that has been smoothed by heat softening after being applied on the film A. It is the laminated film characterized by having.
[0012]
Further, the present invention is the laminated film of the first invention, wherein the one film A is a base film and the other film C is a heat-sealable film.
[0013]
Further, the present invention is the laminated film according to the first invention, wherein the area ratio of air bubbles present between the one film A and the other film C laminated and bonded is 25% or less.
[0014]
Next, in the second invention of the present invention, one film A is continuously unwound from the unwinding portion, and a solventless adhesive that is cured with an electron beam or ultraviolet light is applied to one side of the film A by a coating unit. A method for producing a laminated film in which a solventless adhesive layer B is formed by coating, and the other film C unwound from another unwinding portion is laminated and adhered to the coated surface of the adhesive layer B by a pressure roll unit. The adhesive layer B applied on the one film A is heated and softened by a heating unit provided between the coating unit and the pressure roll unit, and applied to the film A. Film A-side smooth surface b1 of the solvent-free adhesive layer B, which has been adapted and smoothed by heat softening, and the solvent-free adhesive, which has been adapted and smoothed by heat softening after coating on the film A. Agent After forming the film C side smooth surface b2 of B, and method for producing a laminated film, which comprises laminating the adhesive and film C side smooth surface b2 and the other film C of the solvent-free adhesive layer B is there.
[0015]
Moreover, this invention is a manufacturing method of the laminated | multilayer film of said 2nd invention, The said heating unit is a manufacturing method of the laminated | multilayer film which is any one of heating wire heating, infrared heating, and high frequency heating.
[0016]
Moreover, this invention is a manufacturing method of the laminated film of the said 2nd invention, The said one film A is a base film, The other film C is a manufacturing method of the laminated film which is a heat-sealable film.
[0017]
Next, a third invention of the present invention is a first paper feeding unit that continuously unwinds one film A, a coating unit that applies a solvent-free adhesive on the film A, and a film C on the other side. A second sheet feeding unit that continuously unwinds the film, a pressure roll unit that obtains a laminated film by laminating and pressing the one film A and the other film C through the adhesive, and the laminated film. In a laminating apparatus comprising at least a winding unit for winding up, the solventless adhesive applied on the one film A is heated and smoothed between the coating unit and the pressure roll unit , Film A-side smooth surface b1 of the solventless adhesive layer B smoothed and smoothed by heat softening, and the solventless adhesive layer smoothed and smoothed by heat softening A heating unit for forming the film C-side smooth surface b2 of the film A-side smooth surface b1 of the solvent-free adhesive layer B and the one film A, and the solvent-free adhesive layer. The film C-side smooth surface b2 of B and the other film C are laminated and bonded together by the pressure-bonding roll unit .
[0018]
Moreover, this invention is a manufacturing apparatus of the laminated | multilayer film of said 3rd invention, The said heating unit is a manufacturing apparatus of the laminated | multilayer film whose heating wire heating, infrared heating, or high frequency heating is any.
[0019]
[Action]
The laminated film according to the first aspect of the present invention is a laminated film in which one film A and the other film C are laminated and bonded together with a solventless adhesive layer B cured by electron beam or ultraviolet irradiation. The one film A and the solventless adhesive layer B are entrained in bubbles smoothed in a state in which the film A side is adapted to the surface by heating and softening the solventless adhesive layer B. The other film C and the solventless adhesive layer B are laminated and bonded with the smooth surface b1 having no adhesive as an adhesive interface, and the inclusion of bubbles smoothed by heating and softening the solventless adhesive layer B. The non-smooth surface b2 is laminated and bonded using the bonding interface.
[0020]
Therefore, the film A and the solventless adhesive layer B and the solventless adhesive layer B and the film C are laminated and bonded by a uniform adhesive interface in which there are no bubbles or almost no bubbles, respectively. There is no fogging, the appearance of the laminated film is good, and there is no occurrence of peeling due to bubbles, and it is bonded with good adhesive strength.
[0021]
Next, in the method for producing a laminated film of the second invention of the present invention, an adhesive layer B made of a solventless adhesive coated on a film A such as a base film through a coating roll of a coating unit. However, the surface of the solventless adhesive layer B is heated by heating means such as infrared rays and high frequency in a heating unit while being laminated with pressure bonding while being superimposed on the other film C such as a base film. Then, it is softened and smoothed on one film A, and is leveled evenly before being laminated with the other film B.
[0022]
Therefore, when laminating one film A and the other film B in the pressure roll unit, the contact interface between the one film A and the adhesive layer B or the adhesive layer B and the other film C Mixing of air into the contact interface can be reduced, and poor appearance and further poor adhesion of the laminated film at the time of completion of lamination can be solved.
[0023]
In the second invention method, since a solvent-free adhesive that is cured by irradiation with electron beams or ultraviolet rays is used, a high-speed laminating process can be achieved.
[0024]
Next, the manufacturing apparatus of the laminated film of the third invention is such that the adhesive layer B made of a solventless adhesive applied on one film A such as a base film through the application roll of the application unit is a pressure roll. While being laminated with the other film C such as the base film, the adhesive layer B can be smoothed and uniformly leveled by heating means such as infrared rays and high frequency in the heating unit, and is held in the vicinity of the adhesive layer B during lamination. Even in the case of processes where the adhesive hardens instantaneously and the leveling of the adhesive cannot be expected over time, such as electron beam or UV curable type, the laminated film after lamination is completed. No poor appearance or poor adhesion occurs.
[0025]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the embodiment of the laminated film of the first invention will be described in detail according to the side sectional view shown in FIG. 1. One film A and the film A are applied and formed on the film A for irradiation with electron beams or ultraviolet rays. The cured solventless adhesive layer B was laminated and pressed on the adhesive layer B before the solventless adhesive layer B was cured, and adhered by irradiation with an electron beam or ultraviolet rays. A laminated film D composed of the other film C.
[0026]
The film A and the solventless adhesive layer B of the laminated film D are heated and softened (increase the flow value) by solventless adhesive layer B applied and formed on the film A, A smooth surface b1 is formed in a state in which the film A side laminated interface of the solventless adhesive layer B spreads on the film A and is adapted to the film A side, through the smooth surface b1. Laminated and bonded.
[0027]
Then, the other film C and the solventless adhesive layer B of the laminated film D are heated to soften the solventless adhesive layer B applied and formed on the film A (increase the flow value). As a result, the film C-side laminated interface of the solventless adhesive layer B spreads to flow to form a smooth surface b2, and is laminated and bonded via the smooth surface b2.
[0028]
Next, each embodiment of the manufacturing method of the laminated film of 2nd invention and the manufacturing apparatus of the laminated film of 3rd invention is demonstrated in detail according to the general | schematic side view of the manufacturing apparatus shown in FIG.
[0029]
One film A (base film) is unwound and fed from the unwinding section 1 by the infeed roll 2, and this film A is introduced between the coating roll 3 a and the pressure roll 3 b of the coating unit 3.
[0030]
In the coating unit 3, a solventless adhesive layer B that is cured by an electron beam or ultraviolet rays is coated on one side of the film A that is continuously conveyed and supplied by the coating roll 3 a to form a solventless adhesive layer B. . The solventless adhesive 4 is supplied to the application roll 3a by transferring the solventless adhesive 4 supplied between the supply rolls 3c and 3d rotating in contact with each other to one supply roll 3d. The coating roll 3a is rotated in contact with the roll 3d.
[0031]
Thereafter, the solventless adhesive layer B on the film A is heated and softened by a heating unit 5 having heating means 5a such as a heating wire heating device, an infrared heating device, and a high-frequency heating device, and the flow is increased.
[0032]
The solventless adhesive layer B softened on the film A has a smoothed (flattened) layer surface, and the contact interface between the softened adhesive layer B and the film A is in contact with the film A. Smoothes (flattenses) in accordance with the contact surface.
[0033]
Subsequently, the one film A is introduced between the other film C (heat-sealable film) supplied from another unwinding section 6 and the pressure-bonding rolls 7 a and 7 b facing each other in the pressure-bonding roll unit 7. The solventless adhesive layer B is cured by passing the electron beam or ultraviolet ray irradiation unit 8 disposed immediately after the nip, and is applied to the outfeed roll 9 by a pair of opposing pressure rolls 9a and 9b. The laminated film D is manufactured by being introduced and discharged and continuously wound up by the winding unit 10.
[0034]
The above-mentioned solvent-free adhesive that is cured by electron beam or ultraviolet irradiation used in the present invention is a one-component curable solvent-free moisture-curable or two-component curable isocyanate-based material. It is also possible to add a part to an adhesive material that is cured by a line or ultraviolet rays. Regarding the curing of the adhesive layer B at that time, in addition to curing by irradiation with an electron beam or ultraviolet rays in the irradiation unit 8, the laminated film D after being continuously wound up by the winding unit 10 is usually from room temperature to room temperature. Curing for 1 to 5 days in an atmosphere of 60 ° C. promotes a reliable curing reaction of the adhesive.
[0035]
As a solventless adhesive that cures by electron beam irradiation, an oligomer having 1 to several functional groups such as acryloyl group, allyl group, and vinyl group called photopolymerizable oligomer is a resin main component, and irradiation with ionizing radiation Is polymerized by polymerization. In addition, from the height of the curing reaction, acrylic and methacrylic are mainly used, for example, polyester acrylate, polyester methacrylate, epoxy acrylate, epoxy methacrylate, urethane acrylate, urethane methacrylate, polyether acrylate, polyether methacrylate, etc. Various material designs such as oligomers with molecular weights of several hundred to several thousand are possible. Moreover, it does not matter if the resin constituting the adhesive is modified or a photopolymerizable monomer, oligomer, or various additives are added to adjust the viscosity.
[0036]
The electron beam irradiation method used in the present invention may be any method such as an electron curtain method, a scanning method, or a combination method thereof, and is not particularly limited. Moreover, as irradiation conditions, an adhesive agent can be hardened with the dose of 15KGy-50KGy with the acceleration voltage of 50KV-300KV.
[0037]
In addition, as a solventless adhesive that is cured by ultraviolet irradiation, known radical photopolymerization initiators such as benzoin alkyl ether and benzophenone that generate free radicals by absorbing ultraviolet rays in the above electron beam curable adhesive composition Is added.
[0038]
As for ultraviolet irradiation, a known lamp for taking out ultraviolet rays by enclosing mercury, zinc, lead, and deuterium that easily releases a large amount of ultraviolet rays in a transparent container and causing discharge therein can be used.
[0039]
As a coating method and a coating means on one film A (for example, a base film) in the coating unit 3, generally known gravure coating, roll coating, kiss touch coating, die coating, flexo, offset, etc. are all used. Can be used.
[0040]
One film A and / or the other film according to the present invention is uniaxially or biaxially stretched polypropylene, polyester, polyamide, or the like, or aluminum, tin, magnesium, silicon, etc. on one side of these substrates The metal or metal oxide can be exemplified by a thin film formed by a known dry process method (evaporation method such as vacuum vapor deposition), and a single layer film or a laminated film such as paper or aluminum foil can be used as these films. The thickness is suitably about 9 μm to 500 μm, but is not particularly limited.
[0041]
In the present invention, for example, a base film can be used for one film A, and a heat sealable film having a lower melting point than the base film can be used for the other film C.
[0042]
When used as a packaging material, the heat-sealable film is used for heat melting and bonding. For example, low density, medium density, high density polyethylene, ethylene-vinyl acetate copolymer, unstretched Polypropylene, ethylene-methacrylic acid copolymer, ethylene-acrylic acid copolymer, or those cross-linked with zinc or sodium ions, etc., and further, metal or metal oxide on one side as above A thin film having a thickness of about 10 μm to 100 μm is suitable.
[0043]
Next, the bonding in the present invention will be described. The solventless adhesive is coated on one surface of one film A (base film) by the coating roll 3a of the coating unit 3. The viscosity of this adhesive is as follows. In order to improve the wettability to the film A by lowering the thickness, it is appropriate that the roll 3a is heated to about 50 to 100 ° C.
[0044]
Also, in order to flatten the surface of the adhesive coated on the one film A (base film), a metal roll in which a radiant infrared heater or hot water is circulated is pressed against the adhesive layer B. Or a method of spraying hot air, or by irradiating the adhesive layer B with radio waves (RF), the flattening of the adhesive layer B can be promoted. The optimum conditions can be set as appropriate, but the surface temperature of the adhesive layer B is preferably about 35 to 80 ° C.
[0045]
【Example】
Specific examples of the present invention are shown below.
[0046]
<Example 1>
Using the apparatus shown in FIG. 2, as one film A (base film), a biaxially stretched polypropylene film having a thickness of 20 μm is unwound and supplied from one unwinding section 1, and is made of a polyester acrylate. An electron beam curable adhesive 4 was applied by a roll coating method with a coating roll 3a so as to have a processing speed of 120 m / min and a coating amount of 1.8 g / m ² to form an adhesive layer B.
Next, preheating was performed on the surface of the adhesive layer B with a 500 W infrared heater in the heating unit 5, and the surface temperature of the adhesive layer B was adjusted to 60 ° C.
Subsequently, an unstretched polypropylene film 30 μm unwound and fed from another unwinding part 6 is nipped on the adhesive layer B surface of the one film A with a pressure roll part 7 under a condition of 10 kg / cm ² . The laminated film D of the present invention was produced by continuously winding the adhesive layer B while irradiating an electron beam of 175 kV-20 kGy under a nitrogen atmosphere while curing the adhesive layer B.
[0047]
<Example 2>
In the apparatus of FIG. 2, the laminated film D of the present invention was carried out in the same manner as in Example 1 except that dry hot air was used instead of the infrared heater and the surface temperature of the solventless adhesive layer B was 50 ° C. Was made.
[0048]
<Example 3>
A laminated film D of the present invention was produced in the same manner as in Example 1 except that the processing speed was 200 m / min.
[0049]
<Example 4>
A laminated film D of the present invention was produced in the same manner as in Example 1 except that the processing speed was 350 m / min.
[0050]
<Comparative Example 1>
A laminated film of a comparative example was produced in the same manner as in Example 1 except that the solventless adhesive layer B was not heated with an infrared heater.
[0051]
<Comparison test>
The laminated film samples of the present invention obtained in Examples 1 to 4 and the laminated film obtained in Comparative Example 1 were tested for laminate strength and heat seal strength, and the obtained laminated film. The appearance of was evaluated. The results are shown in Table 1.
[0052]

[0053]
<Comparison result>
As can be seen from Table 1, according to the present invention, a beautiful laminate film having no problem in appearance can be obtained, and there is no problem in the laminate strength and heat seal strength. On the other hand, in the laminated film of the comparative example, the generation of bubbles was conspicuous, the appearance defect was confirmed, and a decrease in the laminate strength due to it was recognized.
[0054]
[Table 1]

[0055]
【The invention's effect】
As described above, according to the present invention, the solvent-free adhesive layer coated on one film is heated by the heating means provided between the coating unit and the pressure-bonding roll to smooth the adhesive layer. By removing the bubbles generated by the air mixed in the vicinity of the adhesive and laminating with the other film, the adhesive layer inside and the film and the adhesive at the time of the adhesive application that manifests in high-speed coating There is an effect that air bubbles due to air mixing into the interface with the layer can be removed, and appearance defects and laminate strength reduction can be improved.
[Brief description of the drawings]
FIG. 1 is a side sectional view showing an example of a laminated film of the present invention.
FIG. 2 is a schematic overall side view for explaining a laminated film production method and production apparatus of the present invention.
[Explanation of symbols]
A ... One film B ... Solventless adhesive layer C ... Other film D ... Laminated film b1 ... Smooth surface on film A side b2 ... Smooth surface on film B side 1 ... Unwinding part 2 ... Infeed roll 3 ... Adhesive application unit 4 ... Adhesive 5 ... Heating unit 6 ... Unwinding part 7 ... Crimp roll unit 8 ... Electron beam or ultraviolet irradiation unit 9 ... Outfeed roll 10 ... Winding part

Claims (8)

One film A and the other film C laminated and bonded via a solvent-free adhesive layer B formed on the film A by using a solvent-free adhesive that is cured with an electron beam or ultraviolet rays The film A and the film C are formed by the film A-side smooth surface b1 of the solventless adhesive layer B, which is smoothed by being softened by heating and softening after being applied on the film A, and A laminated film characterized by being laminated and bonded through the film C-side smooth surface b2 of the solventless adhesive layer B, which has been smoothed by being softened by heating and softening after being applied on the film A.   The laminated film according to claim 1, wherein the one film A is a base film, and the other film C is a heat-sealable film.   The laminated film according to claim 1 or 2, wherein an area ratio occupied by air bubbles existing between the one film A and the other film C which are laminated and bonded is 25% or less. One film A is continuously unwound from the unwinding portion, and a solventless adhesive that cures with an electron beam or ultraviolet rays is applied to one side of the film A by a coating unit to form a solventless adhesive layer B In the method for producing a laminated film in which the other film C unwound from another unwinding portion is laminated and bonded to the application surface of the adhesive layer B by a pressure-bonding roll unit, between the coating unit and the pressure-rolling unit. The solvent-free adhesive layer B applied on the one film A is heated and softened by a heating unit provided on the film A , and the solvent-free solution is smoothed by the heat softening after coating on the film A. Film A-side smooth surface b1 of the mold adhesive layer B, and the film C-side smooth surface b2 of the solventless adhesive layer B that has been smoothed by heat softening after being applied onto the film A. After forming the method for producing a laminated film, which comprises laminating the adhesive and film C side smooth surface b2 and the other film C of the solvent-free adhesive layer B.   The method for producing a laminated film according to claim 4, wherein the heating unit is one of heating wire heating, infrared heating, and high-frequency heating.   The method for producing a laminated film according to claim 4 or 5, wherein the one film A is a base film, and the other film C is a heat-sealable film. A first paper feed unit that continuously unwinds one film A, an application unit that applies a solventless adhesive onto the film A, and a second paper feed unit that continuously unwinds the other film C. A laminate comprising at least a pressure-bonding roll unit that obtains a laminated film by superposing and pressing the one film A and the other film C through the adhesive, and a winding unit that continuously winds the laminated film In the apparatus, the non-solvent adhesive applied on the one film A is smoothed by heating between the coating unit and the pressure roll unit, and the non- coated smoothed by the heat softening. The film A side smooth surface b1 of the solvent-type adhesive layer B, and the film C side smooth surface b2 of the solvent-free adhesive layer B smoothed by heat softening. A heating unit to be formed is provided, and the formed film A side smooth surface b1 and one film A of the solventless adhesive layer B and the film C side smooth surface b2 of the solventless adhesive layer B are formed. An apparatus for producing a laminated film, wherein the other film C is laminated and bonded by the pressure-bonding roll unit.   The apparatus for producing a laminated film according to claim 7, wherein the heating unit is any one of heating wire heating, infrared heating, and high-frequency heating.

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