JP2018150428A - Polyester film for laminate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a film for print laminate which has good adhesion between a printed matter and a film, is excellent in workability, is excellent in appearance characteristics such as glossiness after laminate, and has scratch resistance applied thereto by having a hard coat layer on the other of adhesive resin layers, and to provide a print laminate body.SOLUTION: There are provided a polyester film for thermocompression bond print laminate which has a hard coat layer provided on one surface of a base material layer as an outermost surface layer, where a thickness of the hard coat layer is 0.5-2.0 μm, and a surface pencil hardness of the hard coat layer is 2B or harder; and a print laminate body in which the polyester film for print laminate is laminated on an adherend.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a polyester film and a print laminate for print laminate, which have excellent moldability, chemical resistance, deformation resistance, distortion resistance, and scratch resistance imparted with hard coat properties such as wear resistance and high surface hardness. The present invention relates to a laminate.

  A method of laminating printed materials with films for the purpose of protecting the surface of printed materials such as printed paper, imparting water and oil resistance, and imparting luster etc. has been put to practical use and is used for this purpose In general, a film is a print laminate film, and a print laminate obtained by laminating the print laminate film on a printed matter or the like is called a print laminate.

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

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

  In general, in order to increase 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 heat-adhesive resin layer is increased, and the appearance of the heat-adhesive resin layer surface is poor, such as deterioration of the slipperiness or workability due to blocking, and deterioration of gloss after lamination It becomes a problem. Therefore, it is difficult for the prior art to satisfactorily achieve all of the appearance characteristics such as adhesiveness, processability, and gloss after lamination of the film for print lamination.

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

  Laminate films coated with a hard coat layer are widely used for bonding for the purpose of protecting the surface of displays and resin moldings. However, when a hard coat film is bonded to printed matter such as printed paper, If the layer is thickened, there is a problem that haze increases and the appearance of the printed matter is impaired. In addition, if the thickness of the hard coat layer is thick, the processability is poor in the process of cutting after bonding to paper, and it is not preferable to provide a thick hard coat layer on a 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 is rubbed during roll handling, causing damage. For this reason, if the film is wound without using a release film, the front and back surfaces of the laminated film rub against each other and scratches may be caused on the soft side, resulting in hard coating on the soft polypropylene film. 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.

JP-A-10-330706 Japanese Patent Laid-Open No. 2003-200377 JP 2004-268429 A JP 2008-110509 A Japanese Utility Model Publication No. 63-33935 JP 2017-30363 A

  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 adhesion between the printed matter and the film is good, the workability is excellent, there is no curling after processing, and the gloss after lamination. An object of the present invention is to provide a print laminate film and a print laminate that are excellent in appearance characteristics such as property, and have a hard coat layer on the other side of the adhesive resin layer to provide scratch resistance.

As a result of intensive 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 the present invention has been completed.
That is, the gist of the present invention is a polyester film for print lamination provided so that the hard coat layer is the outermost layer on one surface of the polyester film layer, and the thickness of the hard coat layer is 0.5-2. A print laminate polyester film having a surface pencil hardness of 2 B or more of a hard coat layer and a print laminate in which the print laminate polyester film is laminated on an adherend.

  The polyester film for print lamination of the present invention and the print laminate are coated with a hard coat on the outermost layer, so the film has excellent scratch resistance, the gloss of the laminate is excellent, and does not curl after lamination, Since the display effect of the printed material can be enhanced and the adhesiveness between the film and the printing paper is excellent, it is extremely suitable for bonding a printed material with paper attached such as for book covers. Furthermore, since it has good adhesion to other plastics, metals, etc., it can also be used for interior materials, anticorrosive materials for metals, etc.

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

  Hereinafter, the polyester film for print lamination and the print laminate 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 so that the hard coat layer is the outermost layer on one side of the polyester film layer as a base material, and the thickness of the hard coat layer is It is a polyester film for print lamination having a surface pencil hardness of 2B or more of 0.5 to 2.0 μm and a hard coat layer.

  As a specific configuration example, for example, a hard coat layer | polyester film layer | adhesive resin layer, or for the purpose of preventing delamination between the polyester film layer and the adhesive resin layer as shown in FIG. A configuration in which a bonding layer is provided between both layers, such as a hard coat layer, a polyester film layer, a bonding layer, and an adhesive resin layer 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 multilayer structure in which a plurality of layers are stacked. Moreover, it is preferable that it is polyester as a component which comprises a base material layer.

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

  The polyester used in the present invention may be a homopolyester or a copolyester. In the case of a homopolyester, those obtained by polycondensation of an aromatic dicarboxylic acid and an aliphatic glycol are preferred. 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. Typical polyester includes polyethylene terephthalate and the like. On the other hand, the dicarboxylic acid component of the copolyester includes isophthalic acid, phthalic acid, terephthalic acid, 2,6-naphthalenedicarboxylic acid, adipic acid, sebacic acid, oxycarboxylic acid (for example, p-oxybenzoic acid, etc.), etc. 1 type or 2 types or more are mentioned, As a glycol component, 1 type or 2 types or more, such as ethylene glycol, diethylene glycol, propylene glycol, butanediol, 4-cyclohexane dimethanol, neopentyl glycol, is mentioned.

  There is no restriction | limiting in particular as a polymerization catalyst of polyester, A conventionally well-known compound can be used, For example, a titanium compound, a germanium compound, an antimony compound, a manganese compound, an aluminum compound, a magnesium compound, a calcium compound etc. are mentioned. Among these, 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 increased. Furthermore, since a 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 for improving the weather resistance of the film and preventing the deterioration of the liquid crystal. The ultraviolet absorber is not particularly limited as long as it is a compound that absorbs ultraviolet rays and can withstand the heat applied in the production process of the polyester film.

  As the ultraviolet absorber, there are an organic ultraviolet absorber and an inorganic ultraviolet absorber, and an organic ultraviolet absorber is preferable from the viewpoint of transparency. Although it does not specifically limit as an organic type ultraviolet absorber, For example, a cyclic imino ester type, a benzotriazole type, a benzophenone type etc. are mentioned. From the viewpoint of durability, a cyclic imino ester type and a benzotriazole type are more preferable. It is also possible to use two or more ultraviolet absorbers in combination.

  In the polyester layer of the film of the present invention, particles can be blended mainly for the purpose of imparting slipperiness and preventing scratches in each step. The kind of the particle to be blended is not particularly limited as long as it is a particle capable of imparting slipperiness. Specific examples thereof include silica, calcium carbonate, magnesium carbonate, barium carbonate, calcium sulfate, calcium phosphate, and phosphoric acid. Examples 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. Furthermore, precipitated particles obtained by precipitating and finely dispersing a part of a metal compound such as a catalyst during the polyester production process can also be used.

  On the other hand, the shape of the particles to be used is not particularly limited, and any of a spherical shape, a block shape, a rod shape, a flat shape, and the like may be used. Moreover, there is no restriction | limiting in particular also about the hardness, specific gravity, a color, etc. These series of particles may be used in combination of two or more as required.

  Moreover, the average particle diameter of the particle | grains to be used is 5 micrometers or less normally, Preferably it is the range of 0.01-3 micrometers. If it exceeds 5 μm, the surface roughness of the film becomes too rough, which may cause problems in subsequent processes.

Furthermore, the particle content in the polyester layer is usually 5% by weight or less, preferably in the range of 0.0003 to 3% by weight. When there are no or few particles, the transparency of the film becomes high and the film becomes a good film, but the slipperiness may be insufficient. There are cases where improvement is required. Further, when the particle content exceeds 5% by weight, the transparency of the film may be insufficient.
The method for adding 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 for producing the polyester constituting each layer, but it is preferably added after completion of esterification or transesterification.

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

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

  Next, although the manufacture example of the polyester film in this invention is demonstrated concretely, it is not limited to the following manufacture examples at all.

  That is, a method is preferred in which pellets obtained by drying the polyester raw material described above are extruded as a molten sheet from a die using an extruder and cooled and solidified with a cooling roll to obtain an unstretched sheet. 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 an electrostatic application adhesion method and / or a liquid application adhesion method is preferably employed. 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 a 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. Next, the film is stretched in the direction perpendicular to the first stretching direction. In that 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. Subsequently, heat treatment is performed at a temperature of 180 to 270 ° C. under tension or under relaxation within 30% to obtain a biaxially oriented film. In the above-described stretching, a method in which stretching in one direction is performed in two or more stages can be employed. In that case, it is preferable to carry out so that the draw ratios in the two directions finally fall within the above ranges.

  In the present invention, the simultaneous biaxial stretching method can be adopted for the production of the polyester film constituting the laminated polyester film. The simultaneous biaxial stretching method is a method in which the above-mentioned unstretched sheet is usually stretched and oriented in the machine direction and the width direction at a temperature controlled normally at 70 to 120 ° C., preferably 80 to 110 ° C. Is 4 to 50 times, preferably 7 to 35 times, and more preferably 10 to 25 times in terms of area magnification. Subsequently, heat treatment is performed at a temperature of 170 to 250 ° C. under tension or under relaxation within 30% to obtain a stretched oriented film. With respect to the simultaneous biaxial stretching apparatus that employs the above-described stretching method, a conventionally known stretching method such as a screw method, a pantograph method, or a linear driving method can be employed.

  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, it may be provided by in-line coating which treats the film surface during the process of forming a polyester film, or offline coating which is applied outside the system on a once produced film may be adopted. More preferably, it is formed by in-line coating.

  In-line coating is a method of coating within the process of manufacturing a polyester film, and specifically, a method of coating at any stage from melt extrusion of the polyester to heat setting after stretching and winding up. 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 setting, and a film after heat setting and before winding. Although not limited to the following, for example, in sequential biaxial stretching, a method of stretching in the transverse direction after coating a uniaxially stretched film stretched in the longitudinal direction (longitudinal direction) is particularly excellent. According to this method, film formation and coating layer formation can be performed at the same time. In order to perform stretching after coating, the thickness of the coating layer can be changed depending on the stretching ratio, and thin film coating can be performed more easily than an off-line 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.

  Furthermore, in the production of a biaxially stretched polyester film, the film can be restrained in the longitudinal and lateral directions by stretching while gripping the film end with a clip, etc. High temperature can be applied while maintaining the properties. Therefore, since the heat treatment performed after coating can be performed at a high temperature that 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, it can be set as a firm coating layer, and performances such as adhesion to various functional layers that can be formed on the coating layer and wet heat resistance can be improved.

  The heat shrinkage rate in the MD direction (film flow direction) of the polyester film at 150 ° C. for 30 minutes is 1.5% or less, and the heat shrinkage rate in the TD direction (direction perpendicular to the film flow direction) is 0.5% or less. And the problem of flatness such as curling when the laminate is formed is preferable.

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

(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 to be the outermost layer in the polyester film for print lamination of the present invention. As a component of the hard coat layer, for example, an acrylic resin, a urethane resin, a melamine resin, an organic silicate compound, a silicone resin, or a metal oxide can be used. In particular, silicone resins and acrylic resins are preferable in terms of hardness and durability, and acrylic resins are more preferable in terms of curability, flexibility, and productivity. Moreover, it is also preferable that a hard-coat layer contains active energy ray hardening resin, and especially an active energy ray hardening-type acrylic resin is preferable. A thermosetting acrylic resin can also be used, but there are cases where the processing temperature during thermosetting is high and the temperature at which thermal shrinkage of polyester occurs.

  In the hard coat layer, various additives can be further blended as necessary within the range in which the effects of the present invention are not impaired. For example, stabilizers such as antioxidants, light stabilizers, ultraviolet absorbers, surfactants, leveling agents and antistatic agents, antiblocking agents for controlling processability, and the like can be used.

  The process for providing a hard coat layer can be broadly divided into two types: off-line coating and in-line coating.

  In the off-line 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 a substrate layer after film formation. On the other hand, in-line coating is performed by applying the hard coat layer coating material as described above in the film forming process of the base material layer.

  Various coating methods such as reverse coating method, gravure coating method, rod coating method, bar coating method, die coating method or spray coating method can be used as the coating means for the hard coat layer coating material.

  Examples of the active energy rays include electromagnetic waves that polymerize acrylic vinyl groups such as ultraviolet rays, electron beams, and radiation (α rays, β rays, γ rays, etc.). In practice, ultraviolet rays are simple and preferable. . As the ultraviolet ray 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.

  Although the thickness of a hard-coat layer should just be determined according to a use, it is 0.5-2.0 micrometers. When the thickness of the hard coat layer is less than 0.5 μm, it is too thin even if it is sufficiently cured, so that the surface hardness is not sufficient and it tends to be damaged, and it is easily affected by uneven thickness of the substrate. Coating cannot be performed uniformly, and workability is deteriorated.

  In addition, when the hard coat layer is thickened, haze is increased, and brittleness is deteriorated and cracking and peeling are likely to occur, and at the same time, the problem of increased curling of the hard coat film due to curing shrinkage may occur. is there.

  Moreover, it is preferable that the haze after laminating the film of this invention with a polyester film is 3.0% or less from a transparency viewpoint. If it exceeds 3.0%, the printed appearance may be deteriorated when it is bonded to a printed material.

  Moreover, the hard coat layer needs to have a pencil hardness of 2B or more. If it is less than 2B, scratches tend 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)
In the polyester film for print lamination of the present invention, an adhesive resin layer is preferably 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 polyethylene or ethylene-vinyl acetate copolymer based on a metallocene catalyst.

  The melt flow rate (MFR) (value measured according to JIS-K7210 (1999)) of the above-described ethylene-vinyl acetate copolymer is 10 to 30 g / 10 min under conditions of 190 ° C. and a load of 2.16 kg. It is preferable that 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 surface hardness may be reduced, and scratches may be easily obtained.

  Further, the content of vinyl acetate in the ethylene-vinyl acetate copolymer used for the adhesive resin layer is preferably 20 to 30% by mass. Most preferably, it is 20-27 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, blocking may increase and workability may be impaired. At the same time, if the vinyl acetate content exceeds 30% by weight, the hardness may be reduced and the film may be easily damaged.

  The adhesive strength can be improved by controlling the MFR and vinyl acetate content of the adhesive resin, and the adhesive strength value 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 at the time of bonding to paper or the like, and peeling may occur.

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

  If the thickness of the adhesive resin layer is too thin, the adhesive strength is reduced and the glossiness is insufficient and the appearance may be poor. Moreover, since problems, such as blocking, will arise when too thick, preferable thickness is 10-15 micrometers, More preferably, it is 11-13 micrometers.

  Moreover, since the adhesive resin layer causes problems such as blocking if the melting point is too low, and the adhesive force is insufficient if it is too high, the preferable melting point is 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 the slipperiness and improve the workability, and the ten-point average surface roughness (SRz) is 100 nm or more. Preferably, it is 200 to 800 nm.

  Further, the surface of the adhesive resin layer is preferably improved in wet tension by corona discharge treatment, flame 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 40-48 mN / m.

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

  Although the kind of resin used for a joining layer is not specifically limited, In order to improve adhesiveness, resin whose melting | fusing point is lower than a polyester film layer is preferable.

(Production method)
Although the case where a base material layer is a 2 layer structure is described as an example about the manufacturing method of the polyester film for print laminations of this invention below, it is not necessarily limited to this.

  First, a polyester film is prepared as detailed above.

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

  Next, an adhesive resin layer and a resin for the bonding layer are respectively prepared and supplied to the extruder, and the two molten polymers are merged in the polymer tube or the base, and melt-extruded into a sheet form from the T-die. Bonding and cooling are performed 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 both edge portions, the surface of the adhesive resin layer is subjected to corona discharge treatment, ozone treatment, flame treatment, or the like, and then wound into a roll.

  Through these steps, 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 lamination thus obtained can be obtained, for example, by thermocompression bonding with a printing paper as an adherend between a metal roll and a rubber roll heated to 90 to 140 ° C. it can. In this case, the laminating pressure is preferably 5 to 100 kg / cm. As an adherend, in addition to printing paper, it is extremely suitable for book cover, paper CD cases, and the like. In addition, since it has good adhesion to other plastics, metals, etc., it can also be suitably used for interior materials, antirust materials 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:
Using a scanning differential calorimeter (DSC), the peak temperature (° C.) of the endothermic curve accompanying the melting of the crystals obtained when a 10 mg sample was heated at a rate of 10 ° C./min under a nitrogen atmosphere. 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, if two melting peaks are observed, assuming that 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 carried out by laminating a film for printing lamination on a 50 μm biaxially stretched polyester film having a haze of 1.0% with a metal mirror surface roll heated to 100 ° C. at a linear pressure of 60 kg / cm and a speed of 30 m / min. Got. Based on JIS K 7105 (1981), this laminate was measured using a haze meter manufactured by Suga Test Instruments Co., Ltd. so that the average value of 5 points of data was measured as haze. From the viewpoint of transparency, a haze of 3.0% or less is preferable.

(3) Vinyl acetate content:
A calibration curve for each content was created by measurement using the FT-IR method, and the content was determined by taking an ATR spectrum of the film surface or cross section.

(4) Wetting tension:
It measured based on the measuring method prescribed | regulated to JISK6768 (1999) by the liquid mixture of formamide and ethylene glycol monoethyl ether. A specific measurement method is as follows. The mixed solution is immersed in a cotton swab so that the liquid droplets are not dripped, and applied to the sample by moving in a certain direction. The end point is obtained from the shape of the applied liquid film after 2 seconds, and is represented by the surface tension (mN / m) of the liquid.

(5) Thermal contraction rate:
In accordance with JIS Z-1712 (1999), the heat shrinkage rate is obtained by cutting a film into a strip shape (width 10 mm × measured length 100 mm) in the longitudinal direction and the width direction, and in a hot air oven at 150 ° C. for 30 minutes. Read the rate of dimensional change when left unattended and stop at 100 minutes.

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

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

○: No scratch.
Δ: There are no linear scratches, but the surface is thinned and the color changes.
X: There are innumerable linear scratches.

(8) Lami adhesive strength (adhesive strength):
The film for printing laminate and the printing paper were laminated by thermocompression bonding at a linear pressure of 60 kg / cm and a speed of 30 m / min with a metal mirror roll heated to 100 ° C. to obtain a printed laminate. The obtained laminated paper was subjected to thermocompression laminating 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 at a speed of 300 mm / min with a tensile tester. 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 X: less than 300 g / 15 mm

(9) Blocking resistance test (blocking strength):
6 pieces of the film samples that were created were piled up, and 1,670 g × area 128 cm ² (= about 13 g / cm ² ) were placed on top of each other for adhesion, and left for 3 days at a room temperature of 40 ° C. and a relative humidity of 90%. The adhesion strength between the hard coat layer // adhesive resin was measured with a Vangard peel tester and ranked as follows.

(10) Ten-point average roughness (SRz):
Measured according to JIS B-0601 (1982) using a “non-contact three-dimensional fine shape measuring instrument (ET-30HK)” and “three-dimensional roughness analyzer (MODEL SPA-11)” manufactured by Kosaka Laboratory 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: 1mm
Horizontal magnification: 200 times Vertical magnification: 20,000 times Cut off: 0.25 mm
Width direction feed speed: 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:
Cut out section of the film was coated with a hard coat layer on the substrate layer to the ultra-thin sections, RuO ₄ staining, OsO ₄ staining, or staining with double staining of both the ultramicrotomy, TEM (transmission electron microscope) The cross-sectional structure was observed under the following conditions, and the thickness of the hard coat layer was measured from the cross-sectional photograph. The measurement was performed at 10 arbitrary points, and the average value was taken as the hard coat layer thickness.
Measurement device: Transmission electron microscope (H-7100FA type, manufactured by Hitachi, Ltd.)
・ Measurement conditions: Acceleration voltage 100kV
-Sample preparation: frozen ultrathin section method-Magnification: 300,000 times.

(12) Processability evaluation:
Workability was evaluated in view 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 when the thermocompression bonding is performed.

○: Processing was possible without problems.
(Triangle | delta): Although it had a part with high blocking strength or low adhesive strength, it was able to process.
X: Processing defect occurred.

(13) Appearance evaluation:
The appearance was evaluated in view of the haze after coating the hard coat layer on the base material layer and the scratch resistance to the adhesive resin layer side. The adhesive resin layer side can be scratched by winding a film with a hard coat layer on one side of the base material layer and an adhesive resin layer on the other side in a roll shape, and then visually checking the scratches and curls on the adhesive resin layer side. Confirmed. When there was a flaw on the adhesive resin layer side, traces remained thinly after thermocompression lamination, and there was no problem in use if no traces could be visually confirmed during thermocompression lamination. The presence or absence of curling was also evaluated.

○: No problem.
Δ: Some problems, but no problem in use.
X: There is a problem in use.

  EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited to a following example.

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 UV rays are irradiated with a UV lamp to cure. I let you.

  Subsequently, polyethyleneimine was anchor-coated on the opposite surface of the hard coat layer, and ethylene-vinyl acetate copolymer resin 1 (vinyl acetate copolymerization amount = 25% by mass, MFR = 15 g / 10) was used as a raw material for the adhesive resin layer. ) Is melt-extruded with an extruder and cooled while being suppressed with a nip roll having a nip pressure of 0.2 MPa on a casting drum maintained at 25 ° C. so that the biaxially stretched polyester film layer obtained above and the adhesive resin layer are in contact A laminated film in which a hard coat layer, a polyester film layer, a bonding layer, and an adhesive resin layer were integrated in this order.

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

  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 the workability, laminating adhesive strength, laminate Appearance was good. The measurement results are as described 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 copolymerization ratio of 23% by mass and MFR = 25 g / 10 min. As a result, the processability, the laminar adhesive force, and the laminate appearance were all good. The measurement results are as described 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 copolymerization ratio of 25% by mass and MFR = 25 g / 10 min. As a result, the processability, the laminar adhesive force, and the laminate 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 copolymerization rate of 28% by mass and MFR = 25 g / 10 min. As a result, the blocking strength was increased by 11.0 g / 50 mm. The measurement results are as described 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 described 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 changed to 0.5 μm. The measurement results are as described in Table 1.

Example 7:
In Example 1, it formed into a film similarly except having made the thickness of the hard-coat layer (A layer) into 2.0 micrometers. The pencil hardness was HB. The measurement results are as described 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 copolymerization ratio of 20% by mass and MFR = 60 g / 10 min. As a result, the lamination adhesive force was as low as 394 g / 15 mm. Further, the adhesive resin layer laminated on the surface opposite to the hard coat layer was slightly damaged. The measurement results are as described 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 copolymerization ratio of 20% by mass and MFR = 8 g / 10 min. As a result, the laminate adhesive strength was as low as 340 g / 15 mm. The measurement results are as described in Table 1.

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

Comparative Example 1:
In Example 1, it formed into a film similarly except not having apply | coated the hard-coat layer (A layer). As a result, the pencil hardness was as low as less than 4B. Further, scratches were observed in the steel wool abrasion test. The measurement results are as described in Table 1.

Comparative Example 2:
In Example 1, it formed into a film similarly except having made the thickness of the hard-coat layer (A layer) into 5 micrometers. As a result, the haze was 3.5%, and when it was formed into a roll, the adhesive resin surface was damaged and the appearance deteriorated. In addition, cracks occurred in the hard coat layer, and workability deteriorated. The measurement results are as described in Table 1.

Comparative Example 3:
In Example 1, it formed into a film similarly except having made the thickness of the hard-coat layer (A layer) into 0.3 micrometer. As a result, the pencil hardness was 3B, and the steel wool abrasion test showed scratches. Hard coat coating unevenness occurred and processability deteriorated. The measurement results are as described in Table 1.

Comparative Example 4:
Polypropylene resin 1 (MFR = 2.0 g / 10 min, isotactic index (II) = 96% described in Table 2) as a raw material for the polypropylene resin layer (B1 layer) constituting the base material layer, and a low melting point As a raw material for polypropylene resin layer (B2 layer), copolymer polypropylene resin 2 (MFR = 10 g / 10 min, ethylene copolymerization amount = 3.5 mass%, butene copolymerization amount = 4.0 mass%, melting point = 133 ° C., described in Table 2) were each melt-extruded by an extruder, laminated and sheet-shaped in a T-type die, and cooled and solidified on a casting drum set at 30 ° C. Next, the sheet was preheated by a preheating roll group heated to 140 ° C., and then stretched in the longitudinal direction at 135 ° C. in the longitudinal direction to obtain a uniaxially stretched film. Subsequently, the film was held by a clip and heated to 160 ° C. The film was led into an oven, stretched 10 times in the lateral direction, and then heat-set at 155 ° C. while relaxing 5% in the lateral direction to obtain a biaxially stretched film. Thereafter, the surface on which the hard coat layer was provided was subjected to corona discharge treatment to obtain a base material layer made of a 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. However, it was greatly curled and could not be used.

  The polyester film for print lamination and the print laminate of the present invention are not only very suitable for book cover applications, but can also be suitably used for interior materials, anticorrosive 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 laminate provided on one surface of a polyester film layer so that the hard coat layer is the outermost layer, the hard coat layer having a thickness of 0.5 to 2.0 μm, The polyester film for print lamination whose surface pencil hardness of a layer is 2B or more.   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 an 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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