JP2004009566A - Film for heat-fused printed laminate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat-fused printed laminate which has strong adhesive force at a low temperature and under low pressure and excellent high speed lamination properties, is free from delamination between resin layers, does not need a solvent removing apparatus and a recovery apparatus or the like since no anchor coating agent is used, and is excellent in lamination processing properties and surface smoothness. <P>SOLUTION: An adhesive ethylenic resin layer (C layer) which contains an ethylene-acrylic acid copolymer and/or an ethylene-acrylate copolymer and has a main melting peak temperature of 80°C or below and a melt flow rate (MFR) at 190°C of 30-100 g/10 min is laminated on one side of a polypropylene film substrate (A layer). An MT value calculated from the formula: MT [MT=E<SB>MD</SB>/(E<SB>MD</SB>+E<SB>TD</SB>)] (wherein E<SB>MD</SB>is the Young's modulus in the longitudinal direction of the film<SB></SB>and E<SB>TD</SB>is the Young's modulus in the width direction of the film) is 0.4-0.7. <P>COPYRIGHT: (C)2004,JPO

Description

【０１１８】
【表２】

【０１１９】
【発明の効果】
本発明の熱融着プリントラミネート用フィルムは、次のような優れた効果を奏し、ブックカバー用などに極めて好適である。
（１）低温、低圧のラミネート条件及び印刷紙の種類にかかわらず、熱接着力が強く、高速ラミネート性に優れる。
（２）フィルムの長手方向のヤング率が高く、また、長手方向と幅方向のヤング率の差が小さいことから、ラミネート加工時のフィルムの寸法変化が小さくて皺などの発生が少なく、ラミネート加工性に優れる。
（３）ポリプロピレンフィルムの基材層と押出ラミネートする際および印刷物等と接着ラミネートする際に有機溶剤を使用しないことから、作業環境が良好でありしかも溶剤除去装置、回収装置等を必要としない。
（４）フィルムの長手方向と幅方向の熱収縮率の和が小さく、印刷紙にラミネートした後の反りが小さい。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a film for heat fusion print lamination.
[0002]
[Prior art]
For the purpose of protecting the surface of printed matter such as printed paper, or imparting water resistance and oil resistance, giving gloss, etc., and beautifying it, a product obtained by laminating a film on printed matter by thermocompression bonding is on the market. A film used for this purpose is generally called a film for print lamination, and a product obtained by laminating the film for print lamination on a printed material or the like is called a print laminate.
[0003]
As a method of obtaining a print laminate, an anchor coat agent is applied on a thermoplastic resin film layer, an adhesive resin layer made of an ethylene-vinyl acetate copolymer is laminated on the anchor coat surface, and then the adhesive A method is known in which, after oxidizing the surface of a resin layer, the oxidized surface and the printed surface of a printed material are heat-sealed (for example, Japanese Utility Model Application Laid-Open No. 63-19639).
[0004]
In addition to the above, a film for heat fusing print lamination in which a heat bonding layer made of an ethylene-methyl methacrylate copolymer is laminated on one surface of a biaxially stretched polypropylene film, and the wetting tension of the surface of the heat bonding layer is specified. (Japanese Unexamined Patent Publication (Kokai) No. 3-73341) An ethylene acrylic copolymer layer stretched in at least one axis direction is laminated on one surface of a biaxially stretched polypropylene film, and an unstretched unstretched film is formed on the ethylene acrylic copolymer layer. A laminated film for print lamination in which a linear ethylene-based adhesive resin layer is laminated (JP-A-1-320158) is known.
[0005]
In the method using an anchor coating agent, there is a process of applying and drying the adhesive, which not only requires a large-scale facility, but also worsens the work environment due to the scattering of the solvent generated when the adhesive is dried, disaster prevention and air purification. There is a problem that installation and operation costs of the equipment increase. In addition, there is a problem related to productivity such that the coating ability is limited and the processing speed cannot be increased.
[0006]
On the other hand, in the method of laminating the heat bonding layer, the interlayer adhesion between the biaxially stretched polypropylene film and the resin layer laminated thereon may not be sufficient.
[0007]
From the viewpoints described above, a print laminating film having good adhesion between the laminated polypropylene resin layer and the adhesive resin layer without using an anchor coating agent and maintaining the same glossiness as in the past (Japanese Patent Application Laid-Open No. No. 330706) has been developed.
[0008]
However, recently, the thickness of the printed paper is large, and the laminating speed is also increasing in order to increase the productivity. Sufficient adhesive strength could not be obtained due to the lack of melting, and the heat-sealed laminated film and the cover of the printed surface were sometimes peeled off easily. Further, in some cases, it is insufficient to protect the surface of a printed material such as a printed paper or to impart gloss and the like to beautify.
[0009]
Further, a conventional film for print lamination using a successively biaxially oriented polypropylene film as a base layer has a Young's modulus in the longitudinal direction of (E _MD ) Is the Young's modulus in the width direction (E _TD ), The film is stretched by the tension at the time of producing the laminate, wrinkles are easily formed, and the yield is poor.
[0010]
Further, the conventional film for print lamination using a successive biaxially stretched polypropylene film as a base layer has a large difference in heat shrinkage in the longitudinal direction (MD) and the width direction (TD), and is warped when a laminate is produced. However, there is a problem that the flatness is deteriorated.
[0011]
[Problems to be solved by the invention]
An object of the present invention is to solve the above-mentioned conventional problems. Specifically, the adhesive force at low temperature and low pressure is strong, the high-speed laminating property is excellent, and the resin layers laminated after lamination are separated. Because it does not use an anchor coat agent, it does not require a solvent removal device / recovery device, etc. and has excellent laminating processability and excellent flatness of the laminate for heat fusion print lamination. It does not provide films.
[0012]
[Means for Solving the Problems]
An object of the present invention is to provide a polypropylene film substrate layer (layer A) containing at least one selected from ethylene-acrylic acid copolymer and ethylene-acrylic ester copolymer on one surface of a polypropylene film base layer (layer A), wherein the main peak temperature of melting Is a film on which an ethylene-based adhesive resin layer (C layer) having a melting index (MFR) at 80 ° C. or lower and 190 ° C. of 30 to 100 g / 10 minutes is laminated, and the Young's modulus of the film in the longitudinal direction ( This is achieved by a film for heat-sealing print lamination, wherein the MT value calculated from the following formula (1) from EMD) and Young's modulus in the width direction (ETD) is in the range of 0.4 to 0.7. You.
MT = E _MD / (E _MD + E _TD (1)
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
In the present invention, a polypropylene film is used for the substrate layer (A layer). The isotactic index (hereinafter sometimes abbreviated as II) of the polypropylene used as the raw material is preferably in the range of 95 to 99.8%. If II is less than the above range, the Young's modulus of the film may decrease, and the heat shrinkage may increase. On the other hand, if II exceeds the above range, the film-forming properties may deteriorate. II is more preferably in the range of 96 to 99.5%.
[0014]
Further, the mesopentad fraction (hereinafter sometimes abbreviated as mmmm) of the polypropylene used for the layer A is preferably 90 to 99.5%. When mmmm is less than the above range, the Young's modulus when the film is formed is reduced, the heat shrinkage is increased, the thermal dimensional stability tends to be reduced, and the secondary workability such as printing, coating and laminating is inferior. There are cases. If mmmm exceeds the above range, the film forming property tends to decrease. mmmm is more preferably in the range of 94-99%.
[0015]
The melting index at 230 ° C. of the polypropylene used for the A layer (hereinafter sometimes abbreviated as MFR) is preferably in the range of 1 to 20 g / 10 minutes from the viewpoint of film forming property. If the MFR is less than the above range, the melt pressure may increase during filtration and the extrudability may become unstable, resulting in problems such as deterioration in film-forming properties. When the MFR exceeds the above range, there may be a problem that the thickness unevenness of the formed film becomes large. The MFR is more preferably in the range of 1 to 15 g / 10 minutes.
[0016]
The peak temperature of the crystal melting temperature of the polypropylene used for the layer A is preferably 160 ° C. or higher, more preferably 165 ° C. or higher, because the thermal dimensional stability becomes higher.
[0017]
The melt tension (MS) and the melt flow rate (MFR) measured at 230 ° C. of the polypropylene used for the A layer satisfy the following formula (2) and have a high MS and a high melt tension polypropylene (High Melt Strength-PP). HMS-PP).
log (MS)> -0.61 log (MFR) + 0.82 (2)
Here, MS uses a melt tension tester to heat polypropylene to 230 ° C., discharge molten polypropylene at an extrusion speed of 15 mm / min to form a strand, and pull the strand at a rate of 6.5 m / min. Was measured, and the value was defined as MS (unit: cN).
[0018]
The MFR is a value (unit: g / 10 minutes) measured at 230 ° C. under a load of 2.16 kg according to JIS K6758.
[0019]
Since the polypropylene used for the A layer contains HMS-PP satisfying the formula (2), the rigidity in the longitudinal direction, which has been difficult to achieve in conventional longitudinal-transverse sequential biaxial stretching, is high. An axially stretched polypropylene film can be manufactured. That is, this is because HMS-PP suppresses the rearrangement of the vertically oriented crystals in the horizontal direction during the horizontal stretching.
[0020]
The method for obtaining HMS-PP satisfying the above formula (2) is not particularly limited. For example, a method of blending a polypropylene containing a large amount of a high molecular weight component, a method of blending an oligomer or polymer having a branched structure, and a method of No. 121704 discloses a method for introducing a long-chain branched structure into a polypropylene molecule. Alternatively, as described in Japanese Patent No. 2869606, the melt tension and the intrinsic viscosity, the crystallization temperature and the melting point are different. A method of forming a linear crystalline polypropylene which satisfies a specific relationship and has a boiling xylene extraction residual ratio in a specific range is preferably used. In the present invention, it is particularly preferable to use HMS-PP in which a long chain branch is introduced into a polypropylene molecule to increase the melt tension. Specific examples include High Melt Tension PP (HMS-PP) manufactured by Basell and HMS-PP manufactured by Borealis.
[0021]
As an index value indicating the degree of long chain branching of polypropylene, there is a branching index G represented by the following formula (3).
G = [η] _LB / [Η] _Lin (3)
Where [η] _LB Is the intrinsic viscosity of polypropylene having long chain branches, [η] _Lin Is the intrinsic viscosity of a linear crystalline polypropylene having substantially the same weight average molecular weight as a polypropylene having a long chain branch. The intrinsic viscosity can be measured by a known method for a sample dissolved in tetralin. The measurement temperature is 135 ° C. Further, the weight average molecular weight is determined according to M.P. L. It can be measured by the method described by McConnell in American Laboratoy, May, 63-75 (1978), ie, low angle laser light scattering photometry.
[0022]
The branching index of the polypropylene having a long chain branch is preferably in the range of 0.3 to 0.9. If the branching index is less than the above range, the film forming property may be deteriorated. When the branching index exceeds the above range, the Young's modulus in the longitudinal direction when the film is formed may decrease. The branching index is more preferably in the range of 0.4 to 0.7.
[0023]
The MS of the HMS-PP used in the present invention is preferably in the range of 3 to 50 cN. If the MS is less than the above range, the Young's modulus in the longitudinal direction of the film may be insufficient. The larger the MS, the higher the Young's modulus in the longitudinal direction tends to be. However, if the MS exceeds the above range, the film-forming properties may deteriorate. MS is more preferably in the range of 5 to 40 cN, even more preferably 10 to 30 cN.
[0024]
The mixing amount of HMS-PP contained in the polypropylene film base layer of the layer A is not particularly limited, but is preferably 1 to 60% by weight, and is characterized in that the effect can be seen even when a small amount is added. If the mixing amount is less than the above range, the effect of improving the rigidity in the longitudinal direction may be small. If the mixing amount is more than the above range, the stretchability may be deteriorated, and the impact resistance and haze of the film may be deteriorated. The mixing amount of HMS-PP is more preferably 2 to 50% by weight, and still more preferably 3 to 40% by weight.
[0025]
As another preferable configuration of the present invention, the values of MS and MFR of the polypropylene used for the layer A satisfy the following formula (4).
log (MS)> -0.61 log (MFR) + 0.52 (4)
The polypropylene satisfying the formula (4) can be obtained by, for example, mixing HMS-PP and general-purpose polypropylene, or introducing a long-chain branched component into the main chain skeleton of general-purpose polypropylene by copolymerization, graft polymerization, or the like. .
[0026]
When the polypropylene used for the A layer satisfies the formula (4), the rigidity of the film is well-balanced, the handleability of the film is improved, and the thermal dimensional stability in the longitudinal direction and the width direction is improved.
[0027]
The polypropylene used for the layer A preferably satisfies the expression (4 ′), more preferably the expression (4 ″). These can be prepared, for example, by adjusting the amount of HMS-PP added, and the rigidity in the longitudinal direction can be further improved.
log (MS)> -0.61 log (MFR) + 0.56 (4 ')
log (MS)> -0.61 log (MFR) + 0.62 (4 ")
Here, it is desirable to measure the relationship of the above formula using a raw material chip before film formation. However, for the laminated film after film formation, the film is extracted with n-hexane by a method for determining polypropylene II, vacuum-dried at 130 ° C. for 2 hours as a sample, and MS is measured and determined. You can also.
[0028]
The polypropylene used for the A layer is blended with a scrap film or other resin produced when manufacturing the laminated film or other film of the present invention within a range that does not impair the characteristics of the present invention from the viewpoint of economy and the like. You can use it.
[0029]
In addition, a third component other than the above-mentioned polypropylene, for example, a copolymer obtained by randomly copolymerizing a small amount (3 mol% or less) of ethylene, butene, hexene or the like may be used. In the case of the present invention, homopolypropylene is particularly preferred.
[0030]
The addition of 1 to 20% by weight of at least one selected from a petroleum resin substantially free of a polar group and a terpene resin substantially free of a polar group to the polypropylene film used for the layer A can be obtained by adding 1 to 20% by weight of the film. Is preferable because the Young's modulus in the longitudinal and width directions can be increased. If the amount is less than 1% by weight, the effect of addition is not observed. If the amount exceeds 20% by weight, not only the heat resistance is deteriorated, but also the bleed-out of the petroleum resin and the terpene resin to the surface layer is increased, and the slipperiness of the film is reduced. It becomes a tendency.
[0031]
The petroleum resin substantially free of the polar group includes a hydroxyl group (-OH), a carboxyl group (-COOH), and a sulfonic acid group (-SO ₃ Y, Y is H, Na, etc.) and petroleum resins having no polar group, such as modified products thereof, that is, cyclopentadiene-based or higher olefin-based hydrocarbons obtained directly from petroleum unsaturated hydrocarbons. It is a resin used as a raw material. When these resins are added, the glass transition temperature measured by a differential calorimeter is preferably 50 ° C. or higher, more preferably 76 ° C. or higher, so as not to lower the heat resistance. Further, hydrogenated petroleum resin in which hydrogen is added to the petroleum resin and the hydrogenation (sometimes referred to as hydrogenation) ratio is 80% or more, preferably 95% or more is particularly preferable. Furthermore, the petroleum resin is amorphous (that is, when the petroleum resin is measured by a differential calorimeter, substantially no crystal melting is observed) from the viewpoint of compatibilizing with the polypropylene which is the main raw material of the layer A. And the number average molecular weight is preferably 1,000 or less.
[0032]
A terpene resin substantially free of a polar group includes a hydroxyl group (-OH), an aldehyde group (-CHO), a ketone group (-CO-), a carboxyl group (-COOH), a halogen group, a sulfonic acid group (-SO ₃ Y, Y is H, Na, etc.) and terpene resins having no polar group, such as modified products thereof, ie, (C ₅ H ₈ ) _n And a modified compound derived therefrom. Here, n is a natural number of about 2 to 20. Terpene resins are sometimes referred to as terpenoids. Representative compound names include pinene, dipentene, caren, myrcene, ocimene, limonene, terbinolene, terpion, sapinene, tricyclene, pisapolene, zingiperen, santalen, camphorene, millen, totalene, and the like. %, Preferably 90% or more, particularly preferably hydrogenated β-pinene and hydrogenated dipentene.
[0033]
Also, it is not possible to add a small amount of an antistatic agent, an organic lubricant, and inorganic particles or organic crosslinkable particles to the polypropylene film used in the A layer in order to impart slipperiness and improve workability and winding property. Permissible.
[0034]
The antistatic agent is not particularly limited, and examples thereof include an ethylene oxide adduct of a betaine derivative, a quaternary amine compound, an alkyldiethanolamine fatty acid ester, a glycerin fatty acid ester, a stearic acid glyceride, and the like, or a mixture thereof.
[0035]
The organic lubricant is not particularly limited, and examples thereof include amide compounds such as stearamide, erucamide, erucamide, and oleamide, and mixtures thereof.
[0036]
The content of the antistatic agent and the lubricant in the film of the present invention is preferably from 0.3 to 2.0% by weight, and more preferably from 0.5 to 1.0% by weight in terms of antistatic properties and slipperiness. It is more effective to add these to the outermost layer, and it is more preferable to add them to the A layer or the D layer described below.
[0037]
The inorganic particles that can be added to the polypropylene film used for the layer A are inorganic particles of a metal compound. Examples include particles of zeolite, calcium carbonate, magnesium carbonate, alumina, silica, aluminum silicate, kaolin, kaolinite, talc, clay, diatomaceous earth, montmorillonite, titanium oxide, and the like, or a mixture thereof. The organic crosslinkable particles are particles obtained by crosslinking a polymer compound using a crosslinking agent. For example, crosslinked particles of a polymethoxysilane compound, crosslinked particles of a polystyrene compound, crosslinked particles of an acrylic compound, crosslinked particles of a polyurethane compound, crosslinked particles of a polyester compound, crosslinked particles of a fluorine compound, or a mixture thereof Can be mentioned.
[0038]
The average particle diameter of the inorganic particles and the organic crosslinkable particles is preferably in the range of 0.5 to 6 μm. If the average particle size is less than 0.5 μm, the slip property tends to decrease, and if the average particle size exceeds 6 μm, the particles may fall off or the film surface may be easily scratched when the films are rubbed. The total amount of the inorganic particles and / or the crosslinked organic particles is preferably in the range of 0.02% to 0.5% by weight, more preferably in the range of 0.05% to 0.2% by weight. It is preferable in terms of anti-blocking properties, slip properties, transparency and print lamination properties.
[0039]
Further, the polypropylene film used for the layer A is preferably biaxially stretched in view of strength, rigidity, transparency, etc., and particularly preferably biaxially stretched sequentially.
[0040]
In the present invention, the thickness of the layer A which is the base material layer is preferably 5 to 50 μm, more preferably 7 to 30 μm. If the thickness is less than 5 μm, the waist may be weak and wrinkles may be easily formed during print lamination, or the gloss may be poor. On the other hand, if the thickness is more than 50 μm, the laminating property may be poor or the economic efficiency may be poor.
[0041]
Next, the ethylene-based adhesive resin layer (C layer) used in the present invention will be described. It is necessary that the main peak temperature of melting of the C layer is 80 ° C. or lower and the melting index (MFR) at 190 ° C. is 30 to 100 g / 10 minutes.
[0042]
When the main peak temperature of melting of the ethylene-based adhesive resin layer exceeds 80 ° C., sufficient adhesive strength with printing paper cannot be obtained unless the laminating temperature is increased, or the film is peeled off from the printing paper after lamination, It is not preferable because it causes a problem of peeling when bending at the time of bookbinding. The main peak temperature of the melting is preferably 70 ° C or lower, more preferably 60 ° C or lower.
[0043]
When the melt index (MFR) at 190 ° C. of the ethylene-based adhesive resin layer is less than 30 g / 10 minutes, the flowability of the ethylene-based adhesive resin is poor, and when the pressure at the time of lamination is low, the adhesive layer on the printing paper is low. It is not preferable because the bite of the resin deteriorates and the glossiness of the laminated product decreases. On the other hand, if the melting index (MFR) exceeds 100 g / 10 minutes, the extrusion laminating property is deteriorated to cause uneven thickness, and the flatness of the laminate is undesirably deteriorated.
[0044]
Further, the heat of fusion of the ethylene-based adhesive resin layer is preferably 50 J / g or less. When the heat of fusion exceeds 50 J / g, there is a problem that when laminated with a thick printing paper or when the laminating speed is increased, the heat of the laminate is insufficient and the adhesive resin is not sufficiently melted, so that the slipping property is reduced. May happen. The heat of fusion is preferably 40 J / g or less, more preferably 30 J / g or less.
[0045]
It is preferable that the ratio of the main peak temperature of melting of the ethylene-based adhesive resin layer of 80 ° C. or less is 50% or more of the total heat of fusion of the ethylene-based adhesive resin layer. If it is less than 50%, the adhesive strength and bending characteristics may be insufficient, and the print laminating property may be poor.
[0046]
The ethylene-based adhesive resin layer (C layer) is provided with an ethylene-acrylic acid copolymer and an ethylene-acrylate ester in order to impart adhesiveness to the base material layer (A layer) and improve lamination properties. It is necessary to contain at least one selected from copolymers. As these copolymers, those produced by a high-pressure method are preferred because they have excellent extrudability during production of a resin layer. The C layer may be composed of only one or more copolymers selected from these, or may contain another ethylene-based resin.
[0047]
The sum of the contents of acrylic acid and acrylic acid ester in the C layer is preferably 5 to 50% by weight, more preferably 10 to 40% by weight, and further preferably 20 to 35% by weight. When the sum of the contents of acrylic acid and acrylic acid ester is higher than 50% by weight, the self-adhesiveness is increased, and the laminated film is wound into a long length. And the laminability is reduced. On the other hand, if the sum of the contents of acrylic acid and acrylic acid ester is lower than 5% by weight, the adhesive strength at low temperatures is reduced, the bending properties are insufficient, and the print laminating properties may be poor.
[0048]
Examples of the ethylene / acrylic acid copolymer and ethylene / acrylate copolymer used in the C layer include, for example, ethylene / acrylic acid copolymer, ethylene / ethyl acrylate copolymer, and ethylene / butyl acrylate copolymer. Examples thereof include an ethylene / acrylic acid alkyl ester copolymer such as a coalescence and an ethylene / glycidyl acrylate copolymer.
[0049]
The thickness of the ethylene-based adhesive resin layer (C layer) is preferably from 5 to 30 μm, more preferably from 7 to 25 μm. If the thickness is less than 5 μm, the heat laminating property and the rubbing property may be poor. On the other hand, if the thickness is more than 30 μm, the transparency may be impaired, or the economy may be poor. The thickness of the ethylene-based adhesive resin layer is preferably 30% or more of the total film thickness. If the ratio of the thickness of the ethylene-based adhesive resin layer is less than 30%, the glossiness of the laminated product tends to be low.
[0050]
Other ethylene resins can be added to the C layer. Here, other ethylene-based resins include ethylene-based copolymers such as low-density polyethylene and ethylene-vinyl acetate copolymer produced by a high-pressure method, and copolymers of ethylene and α-olefins having 3 to 12 carbon atoms. Polymers may be used, and a plurality of these may be combined. These melting points are preferably at least 60 ° C, more preferably in the range of 70 ° C to 110 ° C. If the melting point is higher than 110 ° C., the adhesive property during thermal lamination may be poor or the rubbing property may be poor. If the melting point is lower than 60 ° C., blocking may increase and handling properties may deteriorate.
[0051]
The MFR of the low-density polyethylene or ethylene-based copolymer added to the ethylene-based adhesive resin layer (C layer) is preferably from 5 to 500 g / 10 minutes, and more preferably from 20 to 300 g / 10 minutes. If the MFR is outside the above range, the melt viscosity is too high or too low, so that the film formability and the fluidity during lamination may be poor.
[0052]
As the ethylene / α-olefin copolymer to be added to the C layer, those produced by high-pressure ionic polymerization, gas-phase polymerization, or solution polymerization in the presence of a single-site catalyst are preferable, and more preferably, extrudability is excellent. Having a long chain branch. Examples of the ethylene / α-olefin copolymer having a long chain branch include “Affinity” manufactured by Dow Chemical Company and “Engage” manufactured by DuPont Dow Elastomer Co., Ltd.
[0053]
Further, the C layer may contain, as components other than the above, for example, a petroleum resin, a terpene resin, a functional group-containing resin, and the like. However, these components are preferably 30% by weight or less. If these components are more than 30% by weight, the print laminating properties may deteriorate. These petroleum resins, terpene resins, and functional group-containing resins preferably have a low melting point, a low heat of fusion, and a low melt viscosity.
[0054]
In order to strengthen the adhesive force between the ethylene-based adhesive resin layer (C layer) and the printing surface of the printing paper, the surface of the ethylene-based adhesive resin layer should be subjected to an oxidation treatment such as a corona discharge treatment or an ozone treatment. Preferably, the surface treatment is performed so that the surface has a wet tension of 34 to 55 mN / m. If it is less than 34 mN / m, the adhesive strength may be insufficient. If it is higher than 55 mN / m, the cost of the oxidation treatment is too high, which is not only economically unsuitable, but also deteriorates by oxidation to lower the adhesive strength. There are cases. Here, the surface for controlling the wetting tension of the C layer is a surface exposed after the C layer is laminated.
[0055]
Next, the B layer used in the present invention will be described. The B layer is formed between the A layer and the C layer. The B layer is a resin layer containing at least one selected from an ethylene-propylene copolymer and an ethylene-propylene-butene terpolymer.
[0056]
Examples of the resin used for the layer B include a random copolymer such as an ethylene / propylene random copolymer, an ethylene / propylene / butene terpolymer, or an ethylene / propylene block copolymer or an olefin-based thermoplastic elastomer. Alternatively, a mixture containing at least one of these copolymers may, for example, be mentioned.
[0057]
Since the layer B contains both an ethylene component and a propylene component, it is possible to enhance the interlayer adhesion between the layer B and the polypropylene film base layer (layer A) and the ethylene-based adhesive resin layer (layer C). Thus, it is possible to obtain a heat-sealing print laminating film in which the laminated polypropylene base layer (layer A) and ethylene-based adhesive resin layer (layer C) do not peel off after print lamination.
[0058]
In addition, since the layer B is laminated, it is not necessary to apply an anchor coat agent in bonding the layer A and the layer C. Therefore, a solvent removing device and a collecting device for this are not required, and both processability and workability can be improved. .
[0059]
The ethylene / propylene random copolymer used in the B layer has an ethylene content of 1 to 10 mol%, and the ethylene / propylene / butene terpolymer has a sum of ethylene and butene content of 3 to 30 mol. % Is preferably used.
[0060]
The olefin-based thermoplastic elastomer used for the layer B preferably has at least one melting point of 85 ° C to 160 ° C, more preferably 100 ° C to 150 ° C. Examples of such an olefin-based thermoplastic elastomer include "Cataroy" manufactured by Sun Allomer and "Newcon" manufactured by Chisso. As a polymerization catalyst such as a copolymer or a thermoplastic elastomer, any of a so-called Ziegler-Natta catalyst or a single-site catalyst is suitably used.
[0061]
In order to increase the interfacial adhesive strength between the layer B and the layer C, an ethylene resin may be blended in the layer B. Ethylene resins include high-pressure low-density polyethylene, linear low-density polyethylene, high-density polyethylene, ultra-low-density polyethylene, ethylene-vinyl acetate copolymer, ethylene-acrylate copolymer, ethylene-methacrylate copolymer. A resin having an ethylene content of 50% or more, such as a polymer, can be added. In particular, an ethylene resin having a main peak of a melting point of 60 ° C to 110 ° C is preferable. In addition to low-density polyethylene and an ethylene copolymer obtained by a high-pressure method, Ziegler-Natta An ethylene / α-olefin copolymer using a catalyst or a single-site catalyst is preferably used.
[0062]
The thickness of the layer B is preferably from 0.5 to 15 μm, more preferably from 1 to 10 μm. If the thickness is less than 0.5 μm, the adhesive force between the layer B and the layer A or between the layer B and the layer C is not sufficient, and the layer may peel off at the interface. On the other hand, if the thickness is more than 15 μm, the transparency may be impaired, or the economy may be poor.
[0063]
Further, in order to enhance the adhesive strength between the A layer and the C layer, a resin layer (B layer) containing at least one selected from the above-mentioned ethylene-propylene copolymer and ethylene-propylene-butene terpolymer is added to B1. As a layer, using a resin layer (B2 layer) containing an ethylene-based resin and at least one selected from ethylene-propylene copolymer, propylene-butene copolymer and ethylene-propylene-butene terpolymer, A configuration in which layers A, B1, B2, and C are stacked in this order may be employed. / Represents lamination.
[0064]
The propylene content in the B2 layer is preferably from 10 to 95 mol%, more preferably from 20 to 90 mol%. When the propylene content is less than 10 mol%, the interfacial adhesive strength between the B1 layer and the B2 layer is weak, and the film may be peeled off here. On the other hand, if the propylene content exceeds 95 mol%, the interfacial adhesive strength between the B2 layer and the C layer is weak, and the film may be peeled off here.
[0065]
Examples of the ethylene resin contained in the B2 layer include high-pressure low-density polyethylene, linear low-density polyethylene, high-density polyethylene, ultra-low-density polyethylene, ethylene-vinyl acetate copolymer, ethylene-alkyl acrylate copolymer And a resin having an ethylene content of 50% or more such as an ethylene / methacrylic acid alkyl ester copolymer, and particularly preferably a resin having a main peak temperature of a melting point of 60 ° C to 100 ° C. Is also good.
[0066]
The MFR of the B1 layer and the B2 layer at 230 ° C. is preferably from 1 to 150 g / 10 minutes, and more preferably from 5 to 50 g / 10 minutes. If the MFR is outside the above range, the melt viscosity is too high or too low, so that the co-extrusion with the A layer or the C layer may be poor.
[0067]
The thickness of the B1 layer is preferably 0.5 to 10 μm, more preferably 1 to 3 μm. If the thickness is less than 0.5 μm, the adhesive strength between the B2 layer and the A layer is not sufficient, and the layer may peel off at the interface. On the other hand, if the thickness is more than 10 μm, the transparency may be impaired, or the economy may be poor.
[0068]
Further, the thickness of the B2 layer is preferably 0.5 to 10 μm, and more preferably 1 to 3 μm. If the thickness is less than 0.5 μm, the adhesive strength between the B1 layer and the C layer is not sufficient, and the layer may peel off at the interface. On the other hand, if the thickness is more than 10 μm, the transparency may be impaired, or the economy may be poor.
[0069]
If necessary, a layer D is laminated on another side of the layer A which is a film base layer, and a layer D / A / B / C or a layer D / A / B1 / B2 / It can have a C layer configuration.
[0070]
By laminating a layer composed of polypropylene or an ethylene / propylene copolymer as the D layer, the gloss of the film of the present invention can be improved.
[0071]
An antistatic agent, a lubricant, an antiblocking agent, and the like may be added to the D layer.
[0072]
Further, as the D layer, a mat-like film can be obtained by laminating an ethylene / propylene block copolymer resin having an ethylene content of 10% by weight or more.
[0073]
The thickness of the D layer is not particularly limited, but is preferably 0.5 to 5 μm. If the thickness is less than 0.5 μm, the thickness uniformity may be impaired. When the thickness is more than 5 μm, when an antistatic agent or a lubricant is added to the A layer, the bleeding property on the surface of the D layer is reduced, and the effect is hardly exhibited.
[0074]
The antistatic agent used in the D layer is not particularly limited. For example, an ethylene oxide adduct of a betaine derivative, a quaternary amine compound, an alkyldiethanolamine fatty acid ester, a glycerin fatty acid ester, a glyceride stearate, or a mixture thereof is used. Can be mentioned.
[0075]
The lubricant used for the D layer is not particularly limited, and examples thereof include amide compounds such as stearamide, erucamide, erucamide, and oleamide, and mixtures thereof.
[0076]
An anti-blocking agent can be added to the D layer. Inorganic and organic crosslinkable particles can be used as the antiblocking agent. The inorganic particles are inorganic particles of a metal compound. Examples include particles of zeolite, calcium carbonate, magnesium carbonate, alumina, silica, aluminum silicate, kaolin, kaolinite, talc, clay, diatomaceous earth, montmorillonite, titanium oxide, and the like, or a mixture thereof. The organic cross-linkable particles are particles obtained by cross-linking a polymer compound using a cross-linking agent, for example, cross-linked particles of a polymethoxysilane compound, cross-linked particles of a polystyrene compound, cross-linked particles of an acrylic compound, polyurethane-based particles. Cross-linked particles of a compound, cross-linked particles of a polyester-based compound, cross-linked particles of a fluorine-based compound, or a mixture thereof. The average particle diameter of the inorganic particles and the organic crosslinkable particles is preferably in the range of 0.5 to 6 μm. If the average particle size is less than 0.5 μm, the slipperiness may decrease. If the average particle size exceeds 6 μm, the particles may fall off, or the film surface may be damaged when the films are rubbed. The total amount of the inorganic particles and the organic crosslinkable particles is preferably in the range of 0.02% to 0.5% by weight, more preferably 0.05% to 0.2% by weight. Is preferred in terms of anti-blocking properties, slip properties, transparency and print lamination properties.
[0077]
A small amount of a nucleating agent other than those described above, a heat stabilizer, an antioxidant, a petroleum resin, etc. may be added to all or some of the layers A, B, and C of the film of the present invention, if necessary. You may. For example, as a nucleating agent, a sorbitol-based nucleating agent, an organic phosphate metal salt-based nucleating agent, and the like are 0.5% by weight or less, and as a heat stabilizer, 2,6-di-tert-butyl-4 is used. 0.5% by weight or less of methylphenol (BHT) and the like, and tetrakis- (methylene- (3,5-di-tert-butyl-4-hydroxy-4-hydrocinnamate)) as an antioxidant Butane (“Irganox” 1010) or the like may be added at 0.5% by weight or less.
[0078]
Next, a method of laminating each layer will be described. The method of laminating each layer is not particularly limited. For example, a three-layer co-extrusion of A layer / B layer / C layer by a T-die method or the like, followed by biaxial stretching, or a co-extruded film of A layer / B layer A method of laminating the C layer after uniaxial stretching and then laterally stretching, and a method of extruding and laminating the C layer from a biaxially stretched two-layer laminated film of the A layer / B layer from a laminating machine (extrusion laminating method) and the like. There is.
[0079]
Among them, in the lamination method of the ethylene-based adhesive resin layer (C layer), the melting point may increase due to crystallization due to stretching, or the adhesive resin adheres to a heating roll or a tenter clip in the stretching step. In some cases, the extrusion lamination method is preferred. At this time, it is preferable that the surface of the C layer is made uneven by a sand blasting roll or an embossing roll in terms of slipperiness and blocking resistance.
[0080]
When the C layer is formed by the extrusion lamination method, if the thermocompression-bonded print laminate film is composed of the A layer / B layer / C layer, the B layer may be co-extruded with the A layer or may be co-extruded with the C layer. May be laminated. In addition, in the case of the configuration of A layer / B1 layer / B2 layer / C layer, it is preferable that the B1 layer and the A layer are coextruded and laminated, and the B2 layer is coextruded and laminated with the C layer. When the D layer is laminated, it is preferably formed by co-extrusion with the A layer.
[0081]
The film for heat-sealing print lamination of the present invention has a Young's modulus (E _MD ) And the Young's modulus in the width direction (E _TD ) Needs to be in the range of 0.4 to 0.7.
MT = Y _MD / (Y _MD + Y _TD (1)
This is because a laminated film having an MT value in this range has a small difference in rigidity between the longitudinal direction and the width direction, and has a small twist and curl after lamination with printing paper, and becomes a laminated body having good shape retention. If the MT value is less than 0.4, the tensile strength at the time of lamination is reduced due to poor rigidity in the longitudinal direction, and the film is stretched to cause wrinkles and the yield is reduced. On the other hand, if the MT value exceeds 0.7, the rigidity in the width direction is inferior, so that the rigidity of the entire film becomes insufficient and the flatness is deteriorated, which is not preferable.
[0082]
The method for setting the MT value in the range of 0.4 to 0.7 is not particularly limited. For example, as the composition of the base material layer (A layer), II is 95 to 99.8% and mmmm is 90 to 99. To 5% isotactic polypropylene, high melt tension polypropylene (HMS-PP) having a long chain branch and petroleum resin substantially free of polar groups and / or terpene resin substantially free of polar groups are added. Then, it is achieved by performing biaxial stretching. At this time, the film is preferably stretched 5 times or more, preferably 7 times or more in the longitudinal direction (the longitudinal direction of the film). As the biaxial stretching method, there are a sequential biaxial stretching method, a simultaneous biaxial stretching method, and a Tubler stretching method, but the sequential biaxial stretching method is preferable in terms of production cost.
[0083]
The Young's modulus of the film of the present invention in both the longitudinal direction and the width direction is preferably 1 GPa or more. If it is less than 1 GPa, the tensile strength at the time of laminating may decrease, wrinkles may be formed, and the laminating properties may deteriorate. The Young's modulus is more preferably 1.5 GPa or more, and still more preferably 2 GPa or more.
[0084]
The sum of the heat shrinkage at 120 ° C. in the longitudinal direction (MD) and the width direction (TD) of the film of the present invention is preferably 3% or less. If the sum of the heat shrinkage at 120 ° C. in the longitudinal direction (MD) and the width direction (TD) exceeds 3%, the laminate may be warped and its use may be limited. For example, warpage may be noticeable when used for a book cover or the like. The method for producing a laminated film having such a heat shrinkage is not particularly limited. For example, when biaxially stretching using the same resin composition of the substrate layer (layer A) as in the method for obtaining the MT value, the transverse stretching temperature To 130 ° C. or higher and then a heat setting step at a temperature equal to or higher than the vertical and horizontal stretching temperatures.
[0085]
Hereinafter, a preferred method for producing the film for thermocompression bonding and printing according to the present invention will be described, but the present invention is not necessarily limited thereto.
[0086]
An extruder heated to 240 ° C. to 280 ° C. for the polypropylene forming the A layer and an extruder heated to 220 ° C. to 280 ° C. for the composition containing the ethylene / propylene copolymer compound for forming the B1 layer. And the molten polymer is laminated in a die, discharged from a gap, wound around a casting drum maintained at 30 to 70 ° C., and cooled and solidified to obtain an unstretched sheet. The sheet is introduced into an oven heated to 120 ° C. to 150 ° C., preheated, stretched 5 to 10 times in the longitudinal direction, cooled, and then made into a uniaxially stretched film, and then guided to a tenter heated to 160 ° C. to 190 ° C. The film is stretched 7 to 10 times in the width direction, and further heat-treated at 150 to 170 ° C. while relaxing by several percent. Next, after the edges are cut and removed, the surfaces of the layer A and the layer B1 are subjected to corona discharge treatment as necessary and wound up to obtain a biaxially oriented polypropylene film.
[0087]
Next, the polypropylene biaxially stretched film is passed between a casting drum kept at 5 ° C. to 50 ° C. and a silicon rubber-based nip roll, and ethylene-propylene-butene terpolymer for forming B2 layer and polyethylene are mixed. The composition is contained in an extruder C heated to 200 ° C. to 260 ° C., and the ethylene-based adhesive resin raw material forming the C layer is supplied to an extruder D heated to 200 ° C. to 260 ° C. to form a molten polymer. Are laminated in a die, discharged from the gap, and extrusion-laminated so that the B2 layer is laminated on the B1 layer. At this time, the surface of the layer C is in contact with the casting drum surface, and the surface of the polypropylene-based biaxially stretched film is in contact with the nip roll side. In addition, it is preferable that the surface of the casting drum at this time is sandblasted to form irregularities on the surface of the C layer to impart slipperiness and blocking resistance.
[0088]
Next, the term definition and the measurement method used in the present invention will be described below.
(1) Melting temperature, heat of fusion
5 mg of the surface resin was sealed in an aluminum pan and charged in a thermal analyzer RDC220 manufactured by Seiko Instruments Inc., and the temperature was increased at a rate of 10 ° C./min. The temperature at the highest endothermic peak accompanying the crystal melting was melted. And the melting area at that time is determined as the heat of fusion ΔHu (J / g). The heat of fusion was calculated from the area of the endothermic peak from the start to the end of the peak using the built-in program of the company's thermal analysis system SSC5200. If a mixture of two or more resins has a plurality of endothermic peaks, the point with the largest peak is taken as the main peak temperature, and the sum of the heats of crystal fusion determined from the areas of the endothermic peaks from the start to the end of each peak is calculated. The heat of fusion was used. The surface layer resin of the laminated film is measured by shaving off the surface layer with a razor.
[0089]
(2) Isotactic index (II)
The isotactic index (II) is determined from the boiling n-heptane extraction residue. The sample is extracted with boiling n-heptane for a certain period of time, and the isotactic index is calculated by obtaining the weight (%) of the unextracted portion. Specifically, the cylindrical filter paper is dried at 110 ± 5 ° C. for 2 hours, and left in a constant temperature and humidity room for 2 hours or more. Weigh precisely using tweezers. This is set on the top of the extractor containing about 80 cc of heptane, and the extractor and the cooler are assembled. This is heated in an oil bath or an electric heater and extracted for 12 hours. Heating is adjusted so that the number of drops from the cooler is at least 130 drops per minute. The cylindrical filter paper containing the extraction residue is taken out, placed in a vacuum dryer, and dried at 80 ° C. and a vacuum of 100 mmHg or less for 5 hours. After drying, it is allowed to stand in a constant temperature and constant humidity for 2 hours, weighed accurately, and calculated by the following formula. Here, Po is the sample weight (g) before extraction, and P is the sample weight (g) after extraction.
Isotactic index (II) (%) = (P / Po) × 100
(3) Mesopentad fraction (mmmm)
The sample was dissolved in o-dichlorobenzene / benzene-D6, and the resonance frequency was 67.93 MHz using a JEOL JNM-GX270 apparatus. ¹³ C-NMR was measured. For the assignment of the obtained spectra and the calculation of the pentad fraction, see T.W. Based on the method performed by Hayashi et al. [Polymer, 29, 138 to 143 (1988)], the peak derived from the methyl group was assigned with the mmmm peak at 21.855 ppm, and the peaks were assigned. The ratio to the total peak area was expressed as a percentage. Detailed measurement conditions are as follows.
Measurement solvent: o-dichlorobenzene (90 wt%) / benzene-D ₆ (10Wt%)
Sample concentration: 15 to 20 wt%
Measurement temperature: 120-130 ° C
Resonance frequency: 67.93 MHz
Pulse width: 10 μsec (45 ° pulse)
Pulse repetition time: 7.091 sec
Data points: 32K
Number of integration: 8168
Measurement mode: noise decoupling.
[0090]
(4) Melt tension (MS)
Using a melt tension tester manufactured by Toyo Seiki, polypropylene is heated to 230 ° C. (polyethylene is 190 ° C.), and molten polypropylene is discharged at an extrusion speed of 15 mm / min to form strands. The strands are heated at a rate of 6.5 m / min. The tension at the time of withdrawal was measured and defined as a melt tension (MS). The MS of the polypropylene film layer of the laminated film of the present invention is measured using a raw material chip before film formation. However, if that is not possible, measure the MS of a single layer of the polypropylene film of the laminated film, scrape off the laminated resin layer on the surface, or process the film by the method determined in II above, and hold the sample. It can be MS of the polypropylene film layer.
[0091]
(5) Melting index (MFR: melt flow rate)
As a measure of flow characteristics (MFR) of polypropylene, an ethylene / propylene random copolymer, an ethylene / propylene / butene random copolymer, etc., it is measured according to JIS K 7210 condition 14 (230 ° C., 21.18 N). In addition, as a scale (MFR) of the flow characteristics of the ethylene-based adhesive resin, it is measured according to JIS K 7210 condition 4 (190 ° C., 21.18 N).
[0092]
(6) Measurement of ethylene, butylene, ethyl acrylate, methyl acrylate and vinyl acetate contents
The FT-IR-ATR spectrum of the resin whose content was known in advance was measured to prepare a calibration curve for each content, and the ATR spectrum of the film surface or cross section was taken to determine the content.
Analyzer: spectrometer = FTS-55A (manufactured by Bio Rad Digilab)
Attachment = Attachment for single reflection ATR
Measurement conditions: light source = special ceramic, detector = MCT, resolution = 4 cm ^-1 ,
Number of integration = 128 times, IRE = Ge, incident angle = 50 °
(7) Wetting tension
It is measured based on a measurement method prescribed in JIS K 6768 using a mixed solution of formamide and ethylene glycol monoethyl ether.
[0093]
(8) Lami adhesion
In order to measure the interfacial laminating adhesive force between the A layer / B1 layer / B2 layer / C layer of the heat-sealing print laminating film, the C layer surfaces are superposed at 120 ° C. 1 kg. After heat sealing under the conditions of 2 sec, a minute amount of ethyl acetate was permeated into each interface to forcibly and partially peel off, and the peeling port was taken out to measure the interfacial adhesive force. Specifically, the force required for peeling the film at 180 ° at a speed of 200 mm / min using Tensilon manufactured by Toyo Baldwin in a measurement atmosphere of 25 ° C. was evaluated, and evaluated by the following four steps, and ◎ and ○ Was passed in practice.
：: 6.5 N / cm or more
：: 3.3 N / cm or more and less than 6.5 N / cm
Δ: 1.6 N / cm or more and less than 3.3 N / cm
X: Less than 1.6 N / cm.
[0094]
(9) Young's modulus of film
In accordance with the method specified in JIS-Z1702, measurement was performed at a measurement temperature of 23 ° C. using an Instron type tensile tester in each of the longitudinal direction and the width direction.
[0095]
(10) Heat shrinkage
In each of the longitudinal direction and the width direction of the film, five samples each having a width of 10 mm and a length of 300 mm were cut out, marked at positions 50 mm from both ends, and a test length of 200 mm (l). ₀ ). Next, the sample was suspended in an oven kept at 120 ° C. with a load of 3 g, taken out after heating for 15 minutes, and measured after cooling. ₁ ) And obtained by the following formula, and the average value of five samples was obtained.
Heat shrinkage S (%) = (l ₀ −l ₁ / L ₀ ) × 100
(11) Print lamination characteristics
The ethylene-based adhesive resin layer (C layer) of the film for print lamination is overlaid on the printing paper surface printed for the book cover, and the linear pressure is 150 N / cm, 30 m / min by a mirror roll (300 mmφ) heated to 90 ° C. For heat-sealing at a speed of
(11-1) Thermal adhesion
At this time, the adhesive strength between the layer C of the film and the printing paper surface (the force required to peel the film 180 ° at a speed of 200 mm / min using a Toyo Baldwin Tensilon in a measurement atmosphere of 25 ° C.) was as follows. Evaluation was made in four steps (at this time, the value of the laminating adhesive strength between the layers of the film was lower than the laminating adhesive strength between the C layer and the printing paper surface, and the value of the laminating adhesive strength was evaluated). did.
：: 3.3 N / cm or more
○: 1.6 N / cm or more and less than 3.3 N / cm
Δ: 0.65 N / cm or more and less than 1.6 N / cm
×: less than 0.65 N / cm
(11-2) Laminating processability
When laminating with 100 sheets of printing paper under the above laminating conditions, film wrinkles of the laminate and displacement of the film from the printing paper were observed and evaluated in the following three grades.
：: There is no wrinkle or displacement of the film in the laminate.
Δ: Wrinkles or misalignment of the film on the laminate was less than 2 sheets.
×: Two or more films were wrinkled or displaced on the laminate.
(11-3) Warpage of laminate
After laminating the laminating film on a 200 μm-thick printing paper under the above conditions, the laminated film was placed on a glass plate, the lifting of the edge of the laminate from the glass plate was measured with a ruler, and evaluated in the following three steps. △ was regarded as practically acceptable.
：: Uplift is 5 mm or less.
Δ: The lift is 5 to 10 mm.
X: Lifting is 11 mm or more.
(11-4) Glossiness
The glossiness of the film surface of the laminated body of the above 11-1 was determined as a glossiness at an entrance angle of 20 ° using a digital variable-angle glossmeter UGV-5D manufactured by Suga Test Instruments Co., Ltd. based on JIS Z8741 method. I asked.
[0096]
【Example】
Hereinafter, examples of the present invention will be described. However, the present invention is not limited to this.
[0097]
Example 1
As the polypropylene constituting the base material layer (A layer), 92% by weight of isotactic polypropylene (PP) having a mesopentad fraction (mmmm) of 92.5%, an isotactic index (II) of 96%, and an MFR of 3.0 g / 10 min. %, The melt tension (MS) is 27 cN and the melt flow rate (MFR) is 3.7 g / 10 min. HMS-PP) 5% by weight, as a petroleum resin substantially free of polar groups, a resin composition obtained by adding and mixing 3% by weight of polydicyclopentadiene having a Tg of 75 ° C., a bromine number of 3 cg / g and a hydrogenation rate of 99%, 0.35 parts by weight of alkyldiethanolamine as an antistatic agent, 0.1 parts by weight of diglycerin ester, and a polymer having an average particle size of 2 μm as crosslinked organic particles. 0.15 parts by weight of a crosslinked particle of a crylic acid-based polymer (crosslinked PMMA) is added, supplied to a twin screw extruder, extruded at 260 ° C. in a gut shape, cooled through a 25 ° C. water bath, and cooled with a tip cutter. After cutting to a length of 3 mm, chips dried at 100 ° C. for 2 hours were supplied to a single screw extruder and melted at 260 ° C.
[0098]
As a resin constituting the layer B, an ethylene / propylene random copolymer (EPC) having an MFR of 7 g / 10 min and an ethylene content of 3.5 mol% was melted by an extruder heated to 260 ° C. The layer melt was co-extruded with a two-layer lamination die, discharged from a gap between the die, wound around a casting drum maintained at 30 ° C., and cooled and solidified to obtain an unstretched sheet. Next, the sheet was introduced into an oven heated to 140 ° C., pre-heated, stretched at 135 ° C. eight times in the longitudinal direction, and cooled to obtain a uniaxially stretched film. Next, after being guided to a tenter heated to 190 ° C. and preheated, it was stretched eight times in the width direction at a temperature of 160 ° C., and further heat-treated at 160 ° C. while allowing 8% relaxation. Next, after cooling on a cooling roll and removing the end by cutting, both sides of the A layer and the B layer are in air at 20 W · min / m. ² And wound up to obtain a biaxially stretched polypropylene film (thickness configuration: layer A / layer B = 14/1 μm).
[0099]
Next, as the ethylene-based adhesive resin layer (C layer), the main peak temperature of melting was 60 ° C., the heat of fusion was 25 J / g, the melting index (MFR) was 35 g / 10 min, and the ethyl acrylate (EA) content was 30 weight. % Ethylene ethyl acrylate (EEA) was fed to an extruder heated to 220 ° C. The biaxially stretched polypropylene film was passed between a casting drum maintained at 20 ° C. and a silicon rubber nip roll, and the melted EEA was extrusion-laminated on the layer B. At this time, the surface of the casting drum was sandblasted to form irregularities on the surface of the layer C, and the surface was further subjected to 15 W · min / m in air. ² Was performed, and the wetting tension on the surface of the C layer was set to 38 mN / m. The layer thickness of the layer C was 12 μm, and a film for heat fusion print lamination having a total thickness of 27 μm was obtained.
[0100]
Table 1 shows the compositions of the layers A, B, and C of the obtained film for heat-sealing print lamination, and Table 2 shows the thickness configuration and characteristics of the film. The Young's modulus in the machine direction (MD) was 1.4 GPa, the Young's modulus in the width direction (TD) was 1.8 GPa, and the MT value was 0.44.
[0101]
Next, the printed printing paper surface and the layer C of the obtained heat-sealing print laminating film are overlapped, and a mirror pressure roll (300 mmφ) heated to 90 ° C. and a silicon rubber roll are used to apply a linear pressure of 15 N / cm and 30 m / m. Heat-press bonding was performed at a speed of 1 minute to obtain a print laminate, and the print lamination characteristics were evaluated. Table 2 shows the evaluation results. As shown in Table 2, the lamination adhesiveness and print lamination characteristics of the laminate were all good.
[0102]
Example 2
As the polypropylene film of the base material layer (layer A), the mesopentad fraction (mmmm) is 98%, the isotactic index (II) is 98.5%, and the MFR is 3.0 g / 10 min. A high melt tension polypropylene (HMS-PP) having a melt tension (MS) of 35 cN and a melt flow rate (MFR) of 4 g / 10 minutes having a long chain branch satisfying the relational expression between MS and MFR of the formula (5) % By weight and 10% by weight of a polyterpene resin (Tg 65 ° C., bromine value 1 cg / g, hydrogenation rate 99%) substantially free of polar groups, and mixed with 0.1% by weight of an alkyldiethanolamine as an antistatic agent. 4 parts by weight, 0.2 parts by weight of diglycerin ester, crosslinked particles of a polymethacrylic acid polymer having an average particle size of 2 μm as crosslinked organic particles ( Bridge PMMA) was added in an amount of 0.25 parts by weight, fed to a twin-screw extruder, extruded in a gut shape at 260 ° C., cooled through a 25 ° C. water bath, cut into 3 mm lengths with a chip cutter, and then cut at 100 ° C. The chips were dried for 2 hours and supplied to a single screw extruder and melted at 260 ° C.
[0103]
The resin constituting the B1 layer was heated to 260 ° C. using an ethylene-propylene-butene terpolymer (EPBC) having an MFR of 6 g / 10 min, an ethylene content of 3 mol% and a butene content of 12 mol%. It is melted by an extruder, and the above-mentioned melt for layer A is co-extruded with a two-layer lamination die, discharged from a gap between the die, wound on a casting drum kept at 50 ° C., and cooled and solidified. To obtain an unstretched sheet. Next, the sheet was introduced into an oven heated to 135 ° C., pre-heated, stretched at 135 ° C. nine times in the longitudinal direction, and cooled to obtain a uniaxially stretched film. Next, it was led to a tenter heated to 190 ° C., stretched 9 times in the width direction, and further heat-treated at 160 ° C. while allowing 5% relaxation. Next, after cooling on a cooling roll and removing the end by cutting, both sides of the A layer and the B1 layer are in air at 20 W · min / m. ² And wound up to obtain a polypropylene biaxially stretched film (thickness configuration: A layer / B1 layer = 13/2 μm).
[0104]
Next, an ethylene / propylene random copolymer resin (EPC) having an MFR of 40 g / 10 min and an ethylene content of 4.7 mol% was used as the resin constituting B2, and the main peak of melting was used as the resin constituting the C layer. Using ethylene ethyl acrylate (EEA) having a temperature of 65 ° C., a heat of fusion of 30 J / g, an MFR of 50 g / 10 min, and an ethyl acrylate (EA) content of 25% by weight, each was fed to a separate extruder heated to 200 ° C. The mixture was extruded and laminated on one side of the biaxially stretched polypropylene film so that the B2 layer was in contact with the B1 layer. The thickness of the B2 layer was 1 μm, the thickness of the C layer was 11 μm, and a film having a total thickness of 27 μm was obtained. Furthermore, 25 W · min / m ² Was subjected to a corona discharge treatment to obtain a heat-sealing print laminating film having a wetting tension of 40 (mN / m).
[0105]
Table 1 shows the compositions of the layers A, B1, B2, and C of the obtained film for heat-sealing print lamination, and Table 2 shows the thickness configuration and characteristics of the film. The Young's modulus in the machine direction (MD) was 1.5 GPa, the Young's modulus in the width direction (TD) was 1.8 GPa, and the MT value was 0.45. Next, a laminate was obtained in the same manner as in Example 1, and the print lamination characteristics were evaluated. Table 2 shows the evaluation results of the laminate. As shown in Table 2, the lamination adhesiveness and print lamination characteristics of the laminate were all good.
[0106]
Example 3
The composition of the material constituting the C layer was the same as that of the EEA resin used for the C layer in Example 1, 80% by weight, the main peak temperature of melting was 100 ° C., the heat of fusion was 70 J / g, the MFR was 7 g / 10 min, and the density was 0.91 g / cm. ³ In the same manner as in Example 2 except that a low-density polyethylene (LDPE) mixture of 20% by weight was used, a film for heat fusion print lamination and a print laminate were obtained. Table 1 shows the compositions of the A layer, the B1 layer, the B2 layer, and the C layer. Table 2 shows the thickness configuration and characteristics of the film. Table 2 shows the evaluation results of the laminate. As shown in Table 2, the lamination adhesiveness and print lamination characteristics of the laminate were all good.
[0107]
Example 4
As a resin composition constituting the C layer, a main peak temperature of melting is 58 ° C., heat of fusion is 25 J / g, MFR is 70 g / 10 min, and ethyl acrylate (EA) content is 25% by weight. And a mixture of 20% by weight of an ethylene / vinyl acetate copolymer (EVA) having a main peak temperature of melting of 70 ° C., a heat of fusion of 20 J / g, an MFR of 50 g / 10 minutes, and a vinyl acetate (VA) content of 28% by weight. A film for heat fusion print lamination and a print laminate were obtained in the same manner as in Example 2 except that a product extruded at 240 ° C. was used. Table 1 shows the compositions of the A layer, the B1 layer, the B2 layer, and the C layer. Table 2 shows the thickness configuration and characteristics of the film. Table 2 shows the evaluation results of the laminate. As shown in Table 2, the lamination adhesiveness and print lamination characteristics of the laminate were all good.
[0108]
Examples 5 and 6
EEA used in Example 2 was used as the resin composition for forming the C layer, and the same procedure as in Example 2 was performed except that the layer thickness of the C layer was 6 μm in Example 5, and the layer thickness was 25 μm in Example 6. Thus, a film for heat fusion print lamination and a print laminate were obtained. Table 1 shows the compositions of the A layer, the B1 layer, the B2 layer, and the C layer. Table 2 shows the thickness configuration and characteristics of the film. Table 2 shows the evaluation results of the laminate. As shown in Table 2, the lamination adhesiveness and print lamination characteristics of the laminate were all good.
[0109]
Example 7
In order to form the D layer on one side of the base material layer (A layer) of Example 2, as the material for the D layer, an ethylene / propylene random copolymer having an MFR of 6 g / 10 min and an ethylene content of 1% (EPC) to which 0.2% by weight of crosslinked particles of a polymethacrylic acid-based polymer (crosslinked PMMA) having an average particle size of 2 μm was added and fed to another extruder and melted at 270 ° C. A heat-sealing print laminating film was obtained in the same manner as in Example 2, except that three layers of D layer / A layer / B1 layer were coextruded in the die using a three-layer lamination die. Table 1 shows the respective compositions of the D layer, the A layer, the B1 layer, the B2 layer, and the C layer. Table 2 shows the thickness configuration and characteristics of the film. Table 2 shows the evaluation results of the laminate. As shown in Table 2, the lamination adhesiveness and print lamination characteristics of the laminate were all good.
[0110]
Example 8
A film for heat fusion print lamination and a print laminate were obtained in the same manner as in Example 2 except that the longitudinal stretching ratio was changed to 11 times. Table 1 shows the compositions of the A layer, B1 layer, B2 layer, and C layer, and Table 2 shows the thickness configuration and characteristics of the film. The Young's modulus in the machine direction (MD) was 2.3 GPa, the Young's modulus in the width direction (TD) was 1.5 GPa, and the MT value was 0.60. Table 2 shows the evaluation results of the laminate. As shown in Table 2, the lamination adhesiveness and print lamination characteristics of the laminate were all good.
[0111]
Comparative Example 1
Example 1 was the same as Example 1 except that the high melt tension polypropylene (HMS-PP) was removed from the resin composition of the polypropylene film of the base material layer (layer A) and the longitudinal stretching ratio was 4.7 times. In the same manner, sequential biaxial stretching was performed. The film composition is shown in Table 1, the thickness composition and characteristics of the film are shown in Table 2, and the evaluation results of the laminate are shown in Table 2. The Young's modulus in the machine direction (MD) was 0.8 GPa, the Young's modulus in the width direction (TD) was 2.0 GPa, and the MT value was 0.29. Since the MT value is low, the film is stretched by the tension during lamination, wrinkles are formed at the end of the laminate, and the sum of the heat shrinkage at 120 ° C. in the longitudinal direction (MD) and the width direction (TD). Was 4.5%, and the laminate was warped.
[0112]
Comparative Example 2
As a polypropylene constituting the base material layer (A layer), isotactic polypropylene (PP) having a mesopentad fraction (mmmm) of 90%, an isotactic index (II) of 94%, and an MFR of 3.2 g / 10 min. Sequential biaxial stretching was performed in the same manner as in Example 1 except that the longitudinal stretching ratio was 5 times and the horizontal stretching ratio was 10 times. The film composition is shown in Table 1, the thickness composition and characteristics of the film are shown in Table 2, and the evaluation results of the laminate are shown in Table 2. The Young's modulus in the machine direction (MD) was 0.7 GPa, the Young's modulus in the width direction (TD) was 2.2 GPa, and the MT value was 0.24. Due to the low MT value, the film is stretched by the tension during lamination, wrinkles are formed at the end of the laminate, and the sum of the heat shrinkage at 120 ° C. in the longitudinal direction (MD) and the width direction (TD). Was 5.2%, and the laminate was warped.
[0113]
Comparative Example 3
Same as Example 2 except that as a resin composition constituting the C layer, an ethylene / vinyl acetate copolymer (EVA) having a main melting temperature of 95 ° C., a heat of fusion of 85 J / g, and an MFR of 17 g / 10 min was used. To obtain a film for heat fusion print lamination. The composition of each layer is shown in Table 1, the thickness composition and characteristics of the film are shown in Table 2, and the evaluation results of the laminate are shown in Table 2. As shown in Table 2, the C layer of the film deviated from all the properties required in the present invention, was inferior in heat adhesion in print lamination properties, and lacked practicality for print lamination. .
[0114]
Comparative Example 4
As the resin composition constituting the C layer, the main peak temperature of melting is 90 ° C., the heat of fusion is 55 J / g, the MFR is 30 g / 10 min, and the density is 0.90 g / cm. ³ Except that low-density polyethylene (LDPE) was used, the same procedure as in Example 2 was carried out to obtain a heat-sealing print laminate film and a print laminate. Table 1 shows the compositions of the A layer, the B1 layer, the B2 layer, and the C layer. Table 2 shows the thickness configuration and characteristics of the film. Table 2 shows the evaluation results of the laminate. As shown in Table 2, the layer C of the film had a high main peak temperature of melting, was inferior in thermal adhesion in print lamination properties, and lacked practicality for print lamination.
[0115]
Comparative Example 5
As the resin composition constituting the C layer, an ethylene / vinyl acetate copolymer (EVA) having a main peak temperature of melting of 75 ° C., a heat of fusion of 50 J / g, an MFR of 25 g / 10 min, and a vinyl acetate (VA) content of 15% by weight. Was carried out in the same manner as in Example 2 except for using, to obtain a film for thermocompression printing and lamination. Table 1 shows the compositions of the layers A, B1, B2, and C. As shown in Table 2, the C layer of the film had a small MFR, was inferior in thermal adhesive force in print lamination properties, and was not practical for print lamination.
[0116]
Comparative Example 6
In Example 2, the C layer was laminated on the surface layer of the A layer without laminating the B1 layer and the B2 layer. As the material for the C layer, an ethylene / methyl acrylic acid copolymer (EMA) having a main peak temperature of melting of 92 ° C., a heat of fusion of 35 J / g, an MFR of 35 g / 10 minutes, and a methyl acrylate (MA) content of 15% is used. did. Other than that, it carried out similarly to Example 2 and obtained the film for heat fusion print lamination. Table 1 shows the compositions of the layers A and C. Table 2 shows the properties of the film and the evaluation results of the laminate. The C layer has a low heat of fusion and a low MFR, but has a low adhesive strength due to a high main peak temperature of melting, and a low adhesive strength between the base material layer (A layer) and the adhesive resin layer (C layer). When the thermal adhesiveness of the laminate was evaluated, interface peeling occurred between the layer A and the layer C, resulting in poor print lamination properties and lacked practicality.
[0117]
[Table 1]

[0118]
[Table 2]

[0119]
【The invention's effect】
The film for heat-sealing print lamination of the present invention has the following excellent effects and is extremely suitable for book covers and the like.
(1) Regardless of low-temperature, low-pressure laminating conditions and types of printing paper, thermal adhesive strength is strong and high-speed laminating properties are excellent.
(2) Since the Young's modulus in the longitudinal direction of the film is high and the difference between the Young's modulus in the longitudinal direction and the Young's modulus in the width direction is small, the dimensional change of the film during laminating is small, and wrinkles and the like are less likely to occur. Excellent in nature.
(3) Since an organic solvent is not used when extruding and laminating with a substrate layer of a polypropylene film and when laminating and bonding with a printed material or the like, the working environment is favorable, and a solvent removing device and a collecting device are not required.
(4) The sum of the heat shrinkage in the longitudinal direction and the width direction of the film is small, and the warpage after lamination on printing paper is small.

Claims (5)

One side of the polypropylene film substrate layer (layer A) contains at least one selected from ethylene / acrylic acid copolymer and ethylene / acrylic ester copolymer, and has a main peak melting temperature of 80 ° C or lower and 190 ° C. the melt index (MFR) is an ethylene-based adhesive resin layer (C layer) are laminated film is 30 to 100 g / 10 min, the longitudinal Young's modulus of the film _{(E MD)} and transverse direction An MT value calculated from the Young's modulus (E _TD ) by the following equation (1) is in the range of 0.4 to 0.7.
MT = E _MD / (E _MD + E _TD ) (1) The resin layer (B layer) containing at least one selected from the group consisting of an ethylene-propylene copolymer and an ethylene-propylene-butene terpolymer is formed between the layer A and the layer C. 4. The film for heat-sealing print lamination according to item 1. The B layer comprises a resin layer (B1 layer) containing at least one selected from ethylene / propylene copolymer and ethylene / propylene / butene terpolymer, and ethylene / propylene copolymer and propylene / butene copolymer. It comprises a resin layer (B2 layer) containing at least one selected from a polymer and an ethylene / propylene / butene terpolymer and an ethylene resin, and is laminated in the order of A layer / B1 layer / B2 layer / C layer. The film for heat-sealing print lamination according to claim 2, wherein The film for heat-sealing print lamination according to any one of claims 1 to 3, wherein the wetting tension of the surface of the C layer is in the range of 34 to 55 mN / m. The film for heat-sealing print lamination according to any one of claims 1 to 4, wherein the sum of the heat shrinkage rates at 120 ° C in the longitudinal direction (MD) and the width direction (TD) is 3% or less.