JP6836067B2 - Polyester film for lamination - Google Patents

Description

The present invention is a polyester film for print lamination and a print having excellent moldability, chemical resistance, deformation resistance, strain resistance, and scratch resistance with hard coat resistance such as abrasion resistance and high surface hardness. It relates to a laminated body.

A method of laminating printed matter with a film has been put into practical use for the purpose of protecting the surface of printed matter such as printed paper, imparting water and oil resistance, and giving gloss and beautification, and is used for this purpose. A film obtained by laminating this print laminating film on a print laminating film, a printed matter, or the like is generally referred to as a print laminating body.

As a method for obtaining a print laminate, a so-called solvent paste, which is bonded to paper using an adhesive, a thermal print laminate, which is bonded using a heat-sensitive adhesive resin layer, and the like are known.

As such an adhesive resin layer, ethylene-vinyl acetate copolymer, ethylene-acrylic acid ester copolymer, ethylene-α-olefin copolymer, ethylene-methacryl acid ester and the like have been proposed (for example, Patent Documents). 1-4). However, when the laminating temperature at the time of manufacturing the printed laminate is low, problems such as insufficient adhesive strength with the printing paper and insufficient glossiness may occur. Further, when the printing paper contains a large amount of residual solvent or the like of ink, there is a problem that the adhesive strength becomes insufficient.

Generally, in order to improve the adhesiveness of the adhesive resin layer, it is necessary to increase the comonomer content of the heat-sensitive adhesive resin to lower the melting point, increase the fluidity of the heat-sensitive adhesive resin, and the like. However, in that case, the stickiness of the surface of the thermosetting resin layer becomes large, and the slipperiness of the surface of the thermosetting resin layer is deteriorated, the processability is poor due to blocking, and the glossiness after laminating is deteriorated. It becomes a problem. Therefore, it is difficult to satisfactorily achieve all of the appearance characteristics such as the adhesiveness, processability, and glossiness after laminating of the print laminating film by the prior art.

On the other hand, it is common practice to apply a coating agent for protecting the surface to a base material such as a steel plate, an inorganic building material, plastic, or paper. Patent Document 5 discloses a decorative sheet provided with a hard coat layer made of an ionizing radiation curable resin on a base paper provided with a pattern and a colored layer. Patent Document 6 describes a method of laminating a polypropylene film on the surface layer of a semi-rigid thermoplastic resin film having a printed pattern layer and further coating an ultraviolet curable resin as a hard coat layer to increase the surface hardness.

Laminated films coated with a hard coat layer are widely used for bonding for the purpose of protecting the surface of displays and resin molded products. However, when the hard coat film is bonded to printed matter such as printed paper, the hard coat is applied. There is a problem that when the layer is made thick, the haze becomes large and the appearance of the printed matter is spoiled. Further, if the thickness of the hard coat layer is thick, the processability is poor in the process of cutting after bonding with paper, and it is not preferable to provide a thick hard coat layer on printed matter such as printed paper.

Further, if the hardness difference between the hard coat layer and the other surface is too large, the surface may be rubbed and scratches may occur during roll handling. Therefore, if the film is wound between the films without using a release film, the front and back surfaces of the laminated films may rub against each other and the soft side surface may be scratched due to scratches. Therefore, the soft polypropylene film is hard coated. It is difficult to laminate the layers, and even if the hard coat layer can be laminated, the film is greatly curled during print lamination, and a fundamental solution is required.

Japanese Unexamined Patent Publication No. 10-330706 Japanese Unexamined Patent Publication No. 2003-20035 Japanese Unexamined Patent Publication No. 2004-268829 Japanese Unexamined Patent Publication No. 2008-110509 Jitsukai Sho 63-33935 JP-A-2017-30363

The present invention has been made in view of the above circumstances, and the problem to be solved by the present invention is that the adhesiveness between the printed matter and the film is good, the workability is excellent, there is no curl after processing, and the gloss after laminating. It is an object of the present invention to provide a print laminating film and a print laminating body which are excellent in appearance characteristics such as properties and have scratch resistance by having a hard coat layer on the other side of an adhesive resin layer.

As a result of diligent studies in view of the above problems, the present inventors have found that the above problems can be easily solved by adopting a specific configuration, and have completed the present invention.
That is, the gist of the present invention is a polyester film for print laminating in which a hard coat layer is provided on one surface of one surface of the polyester film layer so that the hard coat layer is the outermost layer, and the thickness of the hard coat layer is 0.5 to 2. It exists in a polyester film for print laminating having a hardness of 0 μm and a surface pencil hardness of a hard coat layer of 2B or more, and a print laminating body in which the polyester film for print laminating is laminated on an adherend.

Since the polyester film for print lamination and the print laminate of the present invention are hard-coated on the outermost layer, the film has excellent scratch resistance, the laminate has excellent gloss, and does not curl after laminating. Since the display effect of printed matter can be enhanced and the adhesiveness between the film and printing paper is excellent, it is extremely suitable for laminating printed matter pasted on paper such as for book covers. Furthermore, since it has good adhesiveness to other plastics and metals, it can also be used as an interior material and a rust preventive material for metals.

It is a schematic sectional drawing which shows the polyester film for print laminating which concerns on one Embodiment of this invention.

Hereinafter, the polyester film for print lamination and the print laminate body of the present invention will be described.

The polyester film for print lamination of the present invention is a polyester film for print lamination provided on one side of a polyester film layer as a base material so that the hard coat layer is the outermost layer, and the thickness of the hard coat layer is thick. A polyester film for print lamination, which has a thickness of 0.5 to 2.0 μm and a surface pencil hardness of a hard coat layer of 2B or more.

Specific examples of the configuration include a hard coat layer | polyester film layer | adhesive resin layer, and for the purpose of preventing delamination between the polyester film layer and the adhesive resin layer, for example, as shown in FIG. , A configuration such as a hard coat layer | polyester film layer | bonding layer | adhesive resin layer in which a bonding layer is provided between both layers is also preferable. Hereinafter, each layer will be described in detail.

(Base material layer)
The base material layer in the present invention may have a single-layer structure or a multi-layer laminated structure in which a plurality of layers are laminated. Further, as a component constituting the base material layer, polyester is preferable.

The base material layer in the present invention is a layer made of a polyester resin, and may have a single-layer structure or a multi-layer structure, as long as it does not exceed the gist of the present invention other than the two-layer and three-layer structure. The number of layers may be four or more, and is not particularly limited.

The polyester used in the present invention may be a homopolyester or a copolymerized polyester. When it is made of homopolyester, it is preferably obtained by polycondensing an aromatic dicarboxylic acid and an aliphatic glycol. Examples of the aromatic dicarboxylic acid include terephthalic acid and 2,6-naphthalenedicarboxylic acid, and examples of the aliphatic glycol include ethylene glycol, diethylene glycol and 1,4-cyclohexanedimethanol. Examples of typical polyesters include polyethylene terephthalate and the like. On the other hand, examples of the dicarboxylic acid component of the copolymerized polyester include isophthalic acid, phthalic acid, terephthalic acid, 2,6-naphthalenedicarboxylic acid, adipic acid, sebacic acid, and oxycarboxylic acid (for example, p-oxybenzoic acid). One or more of them may be mentioned, and examples of the glycol component include one or more of ethylene glycol, diethylene glycol, propylene glycol, butanediol, 4-cyclohexanedimethanol, neopentyl glycol and the like.

The polyester polymerization catalyst is not particularly limited, and conventionally known compounds can be used. Examples thereof include titanium compounds, germanium compounds, antimony compounds, manganese compounds, aluminum compounds, magnesium compounds and calcium compounds. Among them, titanium compounds and germanium compounds are preferable because they have high catalytic activity, can be polymerized in a small amount, and the amount of metal remaining in the film is small, so that the brightness of the film is high. Further, since the germanium compound is expensive, it is more preferable to use a titanium compound.

The polyester film of the present invention may contain an ultraviolet absorber in order to improve the weather resistance of the film and prevent deterioration of the liquid crystal and the like. The ultraviolet absorber is a compound that absorbs ultraviolet rays and is not particularly limited as long as it can withstand the heat applied in the manufacturing process of the polyester film.

Examples of the ultraviolet absorber include an organic ultraviolet absorber and an inorganic ultraviolet absorber, but an organic ultraviolet absorber is preferable from the viewpoint of transparency. The organic ultraviolet absorber is not particularly limited, and examples thereof include cyclic iminoesters, benzotriazoles, and benzophenones. From the viewpoint of durability, cyclic iminoester type and benzotriazole type are more preferable. It is also possible to use two or more types of ultraviolet absorbers in combination.

Particles can also be blended into the polyester layer of the film of the present invention for the main purpose of imparting slipperiness and preventing scratches in each step. The type of particles to be blended is not particularly limited as long as it is a particle capable of imparting slipperiness, and specific examples thereof include silica, calcium carbonate, magnesium carbonate, barium carbonate, calcium sulfate, calcium phosphate, and phosphoric acid. Examples thereof include inorganic particles such as magnesium, kaolin, aluminum oxide and titanium oxide, and organic particles such as acrylic resin, styrene resin, urea resin, phenol resin, epoxy resin and benzoguanamine resin. Further, during the polyester manufacturing process, precipitated particles in which a part of a metal compound such as a catalyst is precipitated and finely dispersed can also be used.

On the other hand, the shape of the particles to be used is not particularly limited, and any of spherical, lumpy, rod-shaped, flat-shaped and the like may be used. Further, the hardness, specific gravity, color and the like are not particularly limited. Two or more kinds of these series of particles may be used in combination, if necessary.

The average particle size of the particles used is usually 5 μm or less, preferably 0.01 to 3 μm. If it exceeds 5 μm, the surface roughness of the film may become too rough and problems may occur in the subsequent process.

Further, the particle content in the polyester layer is usually 5% by weight or less, preferably 0.0003 to 3% by weight. If there are no or few particles, the transparency of the film will be high and the film will be good, but the slipperiness may be insufficient. Therefore, by putting particles in the coating layer, the slipperiness can be improved. It may be necessary to take measures such as improving it. Further, when the particle content exceeds 5% by weight, the transparency of the film may be insufficient.
The method of adding the particles to the polyester layer is not particularly limited, and a conventionally known method can be adopted. For example, it can be added at any stage in the production of the polyester constituting each layer, but it is preferably added after the esterification or transesterification reaction is completed.

In addition to the above-mentioned particles and ultraviolet absorbers, conventionally known antioxidants, antistatic agents, heat stabilizers, lubricants, dyes, pigments and the like are added to the polyester film of the present invention, if necessary. be able to.

The thickness of the polyester film in the present invention is not particularly limited as long as it can be formed as a film, but it is usually 10 to 25 μm, preferably 10 to 25 μm, in consideration of the glossiness, durability, and processability of the laminated body. It is in the range of 10 to 15 μm.

Next, a production example of the polyester film in the present invention will be specifically described, but the production example is not limited to the following production example.

That is, a method of extruding the above-mentioned dried pellets of the polyester raw material from a die as a molten sheet using an extruder and cooling and solidifying with a cooling roll to obtain an unstretched sheet is preferable. In this case, in order to improve the flatness of the sheet, it is preferable to improve the adhesion between the sheet and the rotary cooling drum, and the electrostatic application adhesion method and / or the liquid coating adhesion method is preferably adopted. Next, the obtained unstretched sheet is stretched in the biaxial direction. In that case, first, the unstretched sheet is stretched in one direction by a roll or tenter type stretching machine. The stretching temperature is usually 70 to 120 ° C., preferably 80 to 110 ° C., and the stretching ratio is usually 2.5 to 7 times, preferably 3.0 to 6 times. Then, it is stretched in a direction orthogonal to the stretching direction of the first stage, in which case the stretching temperature is usually 70 to 170 ° C. and the stretching ratio is usually 3.0 to 7 times, preferably 3.5 to 6 times. is there. Then, the heat treatment is subsequently performed at a temperature of 180 to 270 ° C. under tension or relaxation within 30% to obtain a biaxially oriented film. In the above stretching, a method of stretching in one direction in two or more steps can also be adopted. In that case, it is preferable to finally set the stretching ratios in the two directions within the above ranges.

Further, in the present invention, a simultaneous biaxial stretching method can be adopted for producing a polyester film constituting a laminated polyester film. The simultaneous biaxial stretching method is a method of simultaneously stretching and orienting the unstretched sheet in the mechanical direction and the width direction while the temperature is controlled at 70 to 120 ° C., preferably 80 to 110 ° C., and the stretching ratio is Is 4 to 50 times, preferably 7 to 35 times, and more preferably 10 to 25 times in area magnification. Then, the heat treatment is subsequently performed at a temperature of 170 to 250 ° C. under tension or relaxation within 30% to obtain a stretch-oriented film. As for the simultaneous biaxial stretching apparatus that employs the above-mentioned stretching method, conventionally known stretching methods such as a screw method, a pantograph method, and a linear drive method can be adopted.

The polyester film in the present invention may be provided with a coating layer on at least one surface, and its formation will be described.

Regarding the coating layer, an in-line coating may be provided by treating the film surface during the film forming process of the polyester film, or an offline coating may be adopted in which the film is once produced and coated outside the system. More preferably, it is formed by in-line coating.

The in-line coating is a method of coating in the process of manufacturing a polyester film, and specifically, a method of coating at an arbitrary stage from melting and extruding polyester to stretching, heat fixing, and winding. Usually, it is coated on any of an unstretched sheet obtained by melting and quenching, a stretched uniaxially stretched film, a biaxially stretched film before heat fixing, and a film after heat fixing and before winding. Although not limited to the following, for example, in sequential biaxial stretching, a method of coating a uniaxially stretched film stretched in the longitudinal direction (longitudinal direction) and then stretching in the lateral direction is particularly excellent. According to this method, film formation and coating layer formation can be performed at the same time, which is advantageous in terms of manufacturing cost. Since stretching is performed after coating, the thickness of the coating layer can be changed by the stretching ratio, and thin film coating can be performed more easily as compared with the offline coating film. Further, by providing the coating layer on the film before stretching, the coating layer can be stretched together with the base film, whereby the coating layer can be firmly adhered to the base film.

Further, in the production of a biaxially stretched polyester film, the film can be restrained in the vertical and horizontal directions by stretching while gripping the end of the film with a clip or the like, and in the heat fixing step, a flat surface without wrinkles or the like. High temperature can be applied while maintaining the sex. Therefore, since the heat treatment applied after coating can be set to a high temperature which cannot be achieved by other methods, the film-forming property of the coating layer can be improved, and the coating layer and the base film can be more firmly adhered to each other. Furthermore, a strong coating layer can be formed, and performance such as adhesion to various functional layers that can be formed on the coating layer and moisture heat resistance can be improved.

The heat shrinkage of the polyester film in the MD direction (film flow direction) in the treatment at 150 ° C. for 30 minutes is 1.5% or less, and the heat shrinkage in the TD direction (direction perpendicular to the film flow direction) is 0.5% or less. This is preferable because the problem of flatness such as curl when the laminated body is formed can be alleviated.

The surface of the polyester film in the present invention may be pretreated by corona treatment in advance for the purpose of improving the adhesion to each layer when forming the hard coat layer or the adhesive resin layer.

(Hard coat layer)
In the present invention, a hard coat layer is provided on one side of the base material layer. This hard coat layer is provided so as to be the outermost layer in the polyester film for print lamination of the present invention. The constituent components of the hard coat layer can be, for example, an acrylic resin_, a urethane resin, a melamine resin, an organic silicate compound, a silicone resin, a metal oxide, or the like. In particular, a silicone resin and an acrylic resin are preferable in terms of hardness and durability, and an acrylic resin is preferable in terms of curability, flexibility and productivity. Further, it is preferable that the hard coat layer contains an active energy ray-curable resin, and in particular, an active energy ray-curable acrylic resin is preferable. Although a thermosetting acrylic resin can also be used, the processing temperature at the time of thermosetting may be high and close to the temperature at which heat shrinkage of polyester occurs.

Various additives can be further added to the hard coat layer, if necessary, as long as the effects of the present invention are not impaired. For example, antioxidants, light stabilizers, stabilizers such as ultraviolet absorbers, surfactants, leveling agents and antistatic agents, antiblocking agents for controlling processability, and the like can be used.

The process of providing the hard coat layer can be roughly divided into two types, offline coating and in-line coating, when the process is performed by coating.

In the offline coating, a coating material for a coating layer containing a thermosetting resin or an active energy ray-curable resin as a main component is applied to the base material layer after film formation. On the other hand, in the in-line coating, the coating material for the hard coat layer as described above is applied in the film forming process of the base material layer.

As the coating means for the hard coat layer, various coating methods, for example, a reverse coating method, a gravure coating method, a rod coating method, a bar coating method, a die coating method, a spray coating method and the like can be used.

Examples of the active energy ray include electromagnetic waves that polymerize acrylic vinyl groups such as ultraviolet rays, electron beams, and radiation (α rays, β rays, γ rays, etc.), and practically, ultraviolet rays are convenient and preferable. .. As the ultraviolet source, an ultraviolet fluorescent lamp, a low-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a xenon lamp, a carbon arc lamp, or the like can be used.

The thickness of the hard coat layer may be determined according to the application, but is 0.5 to 2.0 μm. When the thickness of the hard coat layer is less than 0.5 μm, even if it is sufficiently cured, it is too thin and the surface hardness is not sufficient and it tends to be easily scratched. In addition, it is easily affected by the uneven thickness of the base material. The coating cannot be made uniform, and the workability deteriorates.

Further, when the hard coat layer is thickened, the haze becomes large, the brittleness deteriorates and cracks and peeling are likely to occur, and at the same time, the curl of the hard coat film due to curing shrinkage becomes large. is there.

Further, from the viewpoint of transparency, the film of the present invention preferably has a haze of 3.0% or less after being laminated with the polyester film. If it exceeds 3.0%, the printed appearance may be deteriorated when it is attached to a printed matter or the like.

Further, the hard coat layer needs to have a pencil hardness of 2B or more. If it is less than 2B, scratches are likely to remain and the purpose of surface protection cannot be achieved. That is, in the present invention, it can be said that the pencil hardness of the hard coat layer is preferably 2B or more.

(Adhesive resin layer)
The polyester film for print lamination of the present invention preferably has an adhesive resin layer provided on the outermost surface opposite to the surface on which the hard coat layer is formed. The constituent component of the adhesive resin layer is preferably a metallocene-catalyzed polyethylene or ethylene-vinyl acetate copolymer.

The melt flow rate (MFR) of the above-mentioned ethylene-vinyl acetate copolymer (value measured according to JIS-K7210 (1999)) is 10 to 30 g / 10 minutes under the conditions of 190 ° C. and a load of 2.16 kg. Is preferable. If it is less than 10 g / 10 minutes, the adhesive strength tends to be low, and if it exceeds 30 g / 10 minutes, the workability may be impaired, and the hardness of the surface may be lowered, so that it may be easily scratched.

The vinyl acetate content of the ethylene-vinyl acetate copolymer used in the adhesive resin layer is preferably 20 to 30% by mass. Particularly preferably, it is 20 to 27% by mass. If it is less than 20% by mass, the solubility in a solvent tends to be low, and if it exceeds 30% by mass, the blocking strength tends to be high. The blocking strength is preferably less than 15 g / 50 mm, more preferably less than 10 g / 50 mm. When the blocking strength is 15 g / 50 mm or more, the blocking becomes large and the workability may be impaired. At the same time, if the vinyl acetate content exceeds 30% by weight, the hardness may decrease and the vinyl acetate may be easily damaged.

The adhesive strength can be improved by controlling the MFR and vinyl acetate contents of the adhesive resin, and the value of the adhesive strength is preferably 300 g / 15 mm or more, more preferably 400 g / 15 mm or more. If it is less than 300 g / 15 mm, sufficient adhesion cannot be obtained when it is bonded to paper or the like, and peeling may occur.

Various methods can be used as the method for forming the adhesive resin layer, and extrusion laminating is preferable. However, for example, a coating method such as a roll coating method, a gravure coating method, or a comma coating method, or, for example, a gravure printing method or screen printing. Good for printing methods such as.

If the thickness of the adhesive resin layer is too thin, the adhesive strength will be reduced, and the glossiness will be insufficient, resulting in poor appearance. Further, if it is too thick, problems such as blocking will occur. Therefore, the preferable thickness is 10 to 15 μm, and more preferably 11 to 13 μm.

Further, if the melting point of the adhesive resin layer is too low, problems such as blocking occur, and if it is too high, the adhesive force is insufficient. Therefore, the melting point is preferably 70 to 100 ° C, more preferably 75 to 90 ° C.

The surface roughness of the adhesive resin layer is preferably roughened in order to improve slipperiness and workability, and the ten-point average surface roughness (SRz) is 100 nm or more. It is preferably, more preferably 200 to 800 nm.

Further, the surface of the adhesive resin layer is preferably improved in wet tension by corona discharge treatment, frame treatment, ozone oxidation treatment, etc., and the wet tension is 36 mN / m or more, more preferably 38 mN / m or more. More preferably, it is 40 to 48 mN / m.

(Joint layer)
In the polyester film for print lamination of the present invention, it is also preferable to provide a bonding layer between these layers, if necessary, for the purpose of enhancing the adhesion between the polyester film layer and the adhesive resin layer.

The type of resin used for the bonding layer is not particularly limited, but a resin having a melting point lower than that of the polyester film layer is preferable in order to improve adhesion.

(Production method)
Hereinafter, the method for producing the polyester film for print lamination of the present invention will be described by taking the case where the base material layer has a two-layer structure as an example, but the present invention is not necessarily limited to this.

First, the polyester film is prepared as described in detail above.

The hard coat layer (layer A) is coated with a coating liquid containing an ultraviolet curable resin on the polyester film by using a gravure coating method. It is preferable to adopt the gravure coating method for thinly coating the low-viscosity coating liquid. Next, the resin is cured by irradiating it with ultraviolet rays with a UV lamp.

Next, the adhesive resin layer and the resin for the bonding layer are prepared respectively, supplied to the extruder, the two molten polymers are merged in the polymer tube or the mouthpiece, and melt-extruded in the form of a sheet from the T-die. The bonding layer is bonded and cooled on the casting drum so that the bonding layer is in contact with the surface opposite to the surface on which the hard coat layer is provided. Next, after trimming the edge portions at both ends, the surface of the adhesive resin layer is subjected to corona discharge treatment, ozone treatment, frame treatment, or the like, and then wound into a roll.

Through such a step, a polyester film for print lamination in which a hard coat layer, a polyester film layer, a bonding layer, and an adhesive resin layer are laminated in this order can be obtained.

The polyester film for print laminating thus obtained can be obtained by thermocompression bonding between a metal roll heated to 90 to 140 ° C. and a rubber roll together with printing paper as an adherend. it can. The laminating pressure at this time is preferably 5 to 100 kg / cm. As an adherend, in addition to printing paper, it is extremely suitable for book covers, paper CD cases, and the like. Further, since it has good adhesiveness to other plastics and metals, it can be suitably used as an interior material, a rust preventive material for metals, and the like.

The measurement method and evaluation method used in the examples of the present invention will be described below.

(1) Melting point:
At the peak temperature (° C) of the endothermic curve associated with melting of crystals obtained when a 10 mg sample is heated at a rate of 10 ° C / min under a nitrogen atmosphere using a scanning differential calorimeter (DSC). Defined. However, when there are several melting peaks, the weighted average value based on the melting energy calculated from each peak is regarded as the melting point. For example, when two melting peaks are observed, if the first peak temperature is T1 (° C.), the melting energy is U1 (calJ / g), the second peak temperature is T2, and the melting energy is U2, the melting point T is , T = (T1 × U1 + T2 × U2) / (U1 + U2).

(2) Haze:
The measurement was performed by thermocompression bonding a print laminating film on a 50 μm biaxially stretched polyester film with a haze of 1.0% at a linear pressure of 60 kg / cm and a speed of 30 m / min with a metal mirror surface heated to 100 ° C. Got Based on JIS K 7105 (1981), the average value of the data of 5 points measured by using a haze meter manufactured by Suga Test Instruments Co., Ltd. so that light enters from the hard coat layer surface was defined as haze. From the viewpoint of transparency, the haze is preferably 3.0% or less.

(3) Vinyl acetate content:
A calibration curve of each content was prepared by measurement by the FT-IR method, and the ATR spectrum of the film surface or cross section was taken to determine the content.

(4) Wetting tension:
The measurement was carried out based on the measurement method specified in JIS K 6768 (1999) using a mixed solution of formamide and ethylene glycol monoethyl ether. The specific measurement method is as follows. Immerse the mixed solution in a cotton swab so that no droplets drip, and move it in a certain direction to apply it to the sample. The end point is determined from the shape of the applied liquid film after 2 seconds, and is expressed by the surface tension (mN / m) of the liquid.

(5) Heat shrinkage rate:
The heat shrinkage rate is determined by cutting the film into strips (width 10 mm x measurement length 100 mm) in each of the longitudinal and width directions according to JIS Z-1712 (1999), and in a hot air oven at 150 ° C. for 30 minutes. Read the dimensional change rate when left unattended, and stop at 100%.

(6) Pencil hardness:
It was measured according to JIS K 5600-5-4 (1999), and a case having a hardness of 2B or more was regarded as acceptable. The measurement was performed twice, and when the results of the two measurements differed by one unit or more, the sample to be measured was changed and the test was repeated until the results of the two measurements were the same.

(7) Steel wool wear test (scratch resistance):
The surface of the hard coat layer was ^{reciprocated 10 times with a load of 250 g / cm 2} using steel wool # 0000, and the scratch resistance was visually confirmed.

◯: No scratches.
Δ: There are no linear scratches, but the surface is thinly scraped and the color changes.
×: There are innumerable linear scratches.

(8) Lami adhesive strength (adhesive strength):
The print laminating film and the printing paper were thermocompression-bonded with a metal mirror roll heated to 100 ° C. at a linear pressure of 60 kg / cm and a speed of 30 m / min to obtain a print laminate. The obtained laminated paper was thermocompression-bonded and then aged in an atmosphere at a temperature of 25 ° C. and 50% RH for 1 day.

Then, the film and the printing paper were peeled off at a speed of 300 mm / min with a tensile tester. The results were expressed in g / 15 mm and ranked as follows.

◯: 400 g / 15 mm or more Δ: 300 g / 15 mm or more and less than 400 g / 15 mm ×: 300 g / 15 mm or less.

(9) Blocking resistance test (blocking strength):
Six of the prepared film samples were stacked ^{and placed on a weight of 1,670 g x area 128 cm 2} (= about 13 g / cm ² ) for close contact, and left at room temperature 40 ° C. and relative humidity 90% for 3 days. , The adhesion strength between the hard coat layer // adhesive resin was measured by a Vangard peeling tester, and ranked as follows.

(10) Ten-point average roughness (SRz):
Measured by JIS B-0601 (1982) using a "non-contact three-dimensional fine shape measuring instrument (ET-30HK)" and a "three-dimensional roughness analyzer (MODEL SPA-11)" manufactured by Kosaka Laboratory Co., Ltd. .. The number of measurements was 3, and the average value was used. The detailed conditions are as follows.

Measurement surface treatment: Aluminum was vacuum-deposited on the measurement surface to obtain a non-contact method.
Measurement length: 1 mm
Magnification: 200x Magnification: 20,000x Cutoff: 0.25mm
Width direction feed rate: 0.1 mm / sec Length direction feed pitch: 10 μm
Number of feeds in the length direction: 20 times.

(11) Hard coat layer thickness measurement:
A cross section of a film coated with a hard coat layer on a base material layer is cut out into ultrathin sections, which are _{stained by RuO 4} staining, OsO ₄ staining, or double staining of both. TEM (transmission electron microscope) The cross-sectional structure was visually observed in the following conditions, and the thickness of the hard coat layer was measured from the cross-sectional photograph. Any 10 points were measured, and the average value was taken as the hard coat layer thickness.
-Measuring device: Transmission electron microscope (H-7100FA type manufactured by Hitachi, Ltd.)
・ Measurement conditions: Acceleration voltage 100kV
-Sample preparation: frozen ultra-thin section method-Magnification: 300,000 times.

(12) Workability evaluation:
Workability was evaluated in consideration of blocking strength and adhesive strength. When the blocking strength is high, the transportability is deteriorated and the workability is deteriorated, and when the adhesive strength is lowered, peeling occurs at the time of thermocompression bonding lamination.

◯: Processing was possible without any problem.
Δ: Some parts had high blocking strength or low adhesive strength, but processing was possible.
X: A processing defect occurred.

(13) Appearance evaluation:
The appearance was evaluated in consideration of haze after coating the hard coat layer on the base material layer and scratch resistance on the adhesive resin layer side. As for the scratch resistance to the adhesive resin layer side, after winding a film in which a hard coat layer is laminated on one side of the base material layer and an adhesive resin layer is laminated on the other side in a roll shape, scratches and curls on the adhesive resin layer side are visually observed. I confirmed it. If there is a scratch on the adhesive resin layer side, a thin streak mark may remain even after thermocompression bonding lamination, and if no mark can be visually confirmed when thermocompression bonding lamination is performed, there is no problem in use. The presence or absence of curl was also evaluated.

○: No problem.
Δ: There are some problems, but there is no problem in use.
×: There is a problem in use.

Next, the present invention will be described in more detail by way of examples, but the present invention is not limited to the following examples.

Example 1:
Acrylic resin Aikatron PL1L manufactured by Aika Kogyo Co., Ltd. is coated on one side of a polyester film E-5200 (film thickness 12 μm) manufactured by Toyobo Co., Ltd. using a gravure coating method, and is cured by irradiating ultraviolet rays with a UV lamp. I let you.

Next, polyethylene imine was anchor-coated on the opposite surface of the hard coat layer, and as a raw material for the adhesive resin layer, ethylene-vinyl acetate copolymer resin 1 (vinyl acetate copolymer amount = 25% by mass, MFR = 15 g / 10). Minutes) are melt-extruded with an extruder and cooled on a casting drum kept at 25 ° C so that the previously obtained biaxially stretched polyester film layer and the adhesive resin layer are in contact with each other while being suppressed by a nip roll having a nip pressure of 0.2 MPa. , The hard coat layer, the polyester film layer, the bonding layer and the adhesive resin layer were integrated in this order to form a laminated film.

The obtained laminated film was further cut at an edge portion and then subjected to a corona discharge treatment on the ethylene-vinyl acetate copolymer resin side and wound into a roll to obtain a print laminating film.

The thickness composition ratio of the laminated film thus obtained is hard coat layer / polyester film layer / bonding layer / adhesive resin layer = 1 μm / 12 μm / 3.5 μm / 11.5 μm, and has workability, lami adhesive strength, and lamination. The appearance was good. The measurement results are as shown in Table 1.

Example 2:
In Example 1, a film was formed in the same manner except that the adhesive resin layer was an ethylene-vinyl acetate copolymer resin having a vinyl acetate copolymer ratio of 23% by mass and an MFR of 25 g / 10 minutes. As a result, the workability, the lami adhesive strength, and the laminated appearance were all good. The measurement results are as shown in Table 1.

Example 3:
In Example 1, a film was formed in the same manner except that the adhesive resin layer was an ethylene-vinyl acetate copolymer resin having a vinyl acetate copolymer ratio of 25% by mass and an MFR of 25 g / 10 minutes. As a result, the workability, the lami adhesive strength, and the laminated appearance were all good. The measurement results are as shown in Table 1.

Example 4:
In Example 1, a film was formed in the same manner except that the adhesive resin layer was an ethylene-vinyl acetate copolymer resin having a vinyl acetate copolymer ratio of 28% by mass and an MFR of 25 g / 10 minutes. As a result, the blocking strength was increased by 11.0 g / 50 mm. The measurement results are as shown in Table 1.

Example 5:
In Example 1, a film was formed in the same manner except that the thickness of the hard coat layer was 1.5 μm. The pencil hardness of the hard coat layer was B. The measurement results are as shown in Table 1.

Example 6:
In Example 1, a film was formed in the same manner except that the thickness of the hard coat layer was 0.5 μm. The measurement results are as shown in Table 1.

Example 7:
In Example 1, a film was formed in the same manner except that the thickness of the hard coat layer (A layer) was 2.0 μm. The pencil hardness became HB. The measurement results are as shown in Table 1.

Example 8:
In Example 1, a film was formed in the same manner except that the adhesive resin layer was an ethylene-vinyl acetate copolymer resin having a vinyl acetate copolymer ratio of 20% by mass and an MFR of 60 g / 10 minutes. As a result, the Lami adhesive strength was as low as 394 g / 15 mm. In addition, the adhesive resin layer laminated on the opposite surface to the hard coat layer was slightly scratched. The measurement results are as shown in Table 1.

Example 9:
In Example 1, a film was formed in the same manner except that the adhesive resin layer was an ethylene-vinyl acetate copolymer resin having a vinyl acetate copolymer ratio of 20% by mass and an MFR of 8 g / 10 minutes. As a result, the Lami adhesive strength was as low as 340 g / 15 mm. The measurement results are as shown in Table 1.

Example 10:
In Example 1, a film was formed in the same manner except that the C layer was an ethylene-vinyl acetate copolymer resin having a vinyl acetate copolymerization rate of 30% by mass and an MFR of 15 g / 10 minutes. As a result, the blocking strength was increased by 11.0 g / 50 mm. In addition, the adhesive resin layer laminated on the opposite surface to the hard coat layer was slightly scratched. The measurement results are as shown in Table 1.

Comparative Example 1:
In Example 1, a film was formed in the same manner except that the hard coat layer (A layer) was not applied. As a result, the pencil hardness was as low as less than 4B. In addition, scratches were found in the steel wool wear test. The measurement results are as shown in Table 1.

Comparative Example 2:
In Example 1, a film was formed in the same manner except that the thickness of the hard coat layer (layer A) was set to 5 μm. As a result, the haze was 3.5%, and when the roll was formed, the adhesive resin surface was scratched and the appearance was deteriorated. In addition, cracks were generated in the hard coat layer, and the workability was deteriorated. The measurement results are as shown in Table 1.

Comparative Example 3:
In Example 1, a film was formed in the same manner except that the thickness of the hard coat layer (layer A) was set to 0.3 μm. As a result, the pencil hardness was 3B, and scratches were found in the steel wool wear test. In addition, uneven coating of the hard coat occurred, and the workability deteriorated. The measurement results are as shown in Table 1.

Comparative Example 4:
As raw materials for the polypropylene resin layer (B1 layer) constituting the base material layer, polypropylene resin 1 (MFR = 2.0 g / 10 minutes, isotactic index (II) = 96% described in Table 2) and low melting point As a raw material for the polypropylene-based resin layer (B2 layer), copolymerized polypropylene-based resin 2 (MFR = 10 g / 10 minutes, ethylene copolymerization amount = 3.5% by mass, butene copolymerization amount = 4.0% by mass, melting point = 133 ° C. (shown in Table 2) were melt-extruded by an extruder, laminated and extruded into a sheet in a T-shaped base, and cooled and solidified on a casting drum set at 30 ° C. Then, the sheet was preheated with a preheating roll group heated to 140 ° C., then stretched 4.5 times in the longitudinal direction at 135 ° C. to obtain a uniaxially stretched film, and then the film was gripped by a clip and heated to 160 ° C. The film was introduced into an oven, stretched 10 times in the lateral direction, and then heat-fixed at 155 ° C. with a relaxation of 5% in the lateral direction to obtain a biaxially stretched film. Then, the surface to be provided with the hard coat layer was subjected to corona discharge treatment to obtain a base material layer made of biaxially stretched polypropylene film. Using the obtained base material layer, a hard coat layer and an adhesive resin layer were provided in the same manner as in Example 1, and laminated on printing paper, but they curled significantly and could not be used.

The polyester film for print lamination and the print laminate body of the present invention are not only extremely suitable for book cover applications, but also can be suitably used for interior materials, rust preventive materials for metals, and the like.

1: Hard coat layer (A layer)
2: Polyester resin layer (B layer)
3: Bonding layer (D layer)
4: Adhesive resin layer (C layer)

Claims (3)

A polyester film for thermocompression bonding print lamination provided on one surface of the polyester film layer so that the hard coat layer is the outermost layer. The thickness of the hard coat layer is 0.5 to 2.0 μm, and the hard coat is applied. A polyester film for print laminating with a layer surface pencil hardness of 2B or higher. The polyester film for print lamination according to claim 1, wherein an adhesive resin layer is provided on the other surface of the polyester film so as to be the outermost layer. A print laminate in which the polyester film for print laminate according to claim 1 or 2 is laminated on an adherend.

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