JP2004034418A - White laminated polyester film for lamination - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the peeling of a laminated surface under conditions of high temperatures and high humidity. <P>SOLUTION: In a white laminated polyester film, a while polyester resin layer (A layer) comprising a composition containing a polyester resin and a white pigment is laminated on at least one side of a polyester resin layer (B layer). The thickness of the white laminated polyester film is 50-500 μm, and its curl value is 2 mm or below. <P>COPYRIGHT: (C)2004,JPO

Description

【００４６】
【発明の効果】
表１から明らかなように、本発明で必要とされる要件を満たす実施例１〜実施例３のフィルムは、貼り合わせ加工に使用するのに十分な、接着の耐久性を持つ白色積層ポリエステル系フィルムが得られる。これに対し、本発明で必要とされる要件を満たさない比較例１〜比較例３のフィルムは貼り合わせ加工に使用するのに十分な、接着の耐久性を持つ白色積層ポリエステル系フィルムが得られない。
【００４７】
【図面の簡単な説明】
【図１】図１は、本発明の白色積層ポリエステル系フィルムを用いた非接触ＩＣカードの一例を模式的に示す断面図である。
【符号の説明】
Ｃ　非接触ＩＣカード
１　カード構成基材１
２　カード構成基材２
３　樹脂シート
４　アンテナ
５　ＩＣチップ[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a white laminated polyester film for lamination made of a polyester resin. More specifically, the present invention relates to a white laminated polyester film having sufficient humidity stability, heat stability, and stability over time when used as a substrate for an information recording material or the like.
[0002]
[Prior art]
White laminated polyester film is used as a base material for information recording materials such as an IC card such as a magnetic card and a non-contact IC card, and a rewritable card, for example, when used for laminating, during storage, or under use conditions. However, there is a problem that the white laminated polyester film is peeled off from a card produced by laminating the white laminated polyester film. In particular, under high temperature and high humidity, peeling of the white laminated polyester film becomes more remarkable. Some bonded products are also expected to be used inside a closed car under the sunshine, in a tropical area, or in a desert area. In such a situation, the white laminated polyester film may peel off. In many cases, measures against peeling are an important issue.
[0003]
As a countermeasure for this, intensive studies have been made on the selection of an adhesive and an easy bonding process, but it has not always been enough as a countermeasure against peeling.
[0004]
[Problems to be solved by the invention]
SUMMARY OF THE INVENTION An object of the present invention is to provide a white laminated polyester film which solves the above-mentioned drawbacks and improves peeling of a bonded surface of a white laminated polyester film under high temperature and high humidity.
[0005]
[Means for Solving the Problems]
That is, the present invention is a white laminated polyester film in which a white polyester resin layer (A layer) composed of a composition containing a polyester resin and a white pigment is laminated on at least one surface of the polyester resin layer (B layer). A white laminated polyester film having a thickness of 50 to 500 μm and a curl value of 2 mm or less.
[0006]
BEST MODE FOR CARRYING OUT THE INVENTION
The polyester resin in the present invention is a polycondensation of an aromatic dicarboxylic acid such as terephthalic acid, isophthalic acid, or naphthalenedicarboxylic acid or an alkyl ester thereof with a glycol such as ethylene glycol, diethylene glycol, 1,4-butanediol, or neopentyl glycol. Or by polycondensation of a diglycol ester of an aromatic dicarboxylic acid.
[0007]
Examples of the polyester resin include polyethylene terephthalate, polyethylene butylene terephthalate, and polyethylene-2,6-naphthalate. These polyester resins may be homopolymers or copolymers of a third component, but in the present invention, ethylene terephthalate units, butylene terephthalate units or ethylene-2,6-naphthalate units It is preferable to use a polyester resin containing 70 mol% or more, more preferably 80 mol% or more, and still more preferably 90 mol% or more.
[0008]
In the present invention, it is necessary to use a white pigment for the polyester resin layer (layer A).
As the white pigment used in the present invention, titanium oxide, barium sulfate, zinc oxide, zinc sulfide, calcium carbonate and the like can be used. Further, as these white pigments, white pigments which have been subjected to various organic and inorganic surface treatments for the purpose of improving dispersibility in polyester resin and the like can be used. Among these, titanium oxide is particularly preferable for use as a base material for information recording materials because it has a high refractive index and can exhibit high concealing properties with a small amount. These white pigments may be added alone to the polyester resin, or two or more of them may be mixed and added. The content of the white pigment is preferably 5 to 90% (corresponding to 4.8 to 47% by weight based on the weight of the film) based on the entire resin composition constituting the film. If the content is less than 5%, it is difficult to improve the quality such as high refractive index and high concealing property due to the inclusion of the white pigment, and if the content exceeds 90%, the stretchability of the film and the like deteriorate.
[0009]
In the present invention, particles other than the white pigment are preferably contained in the polyester resin within a range not to impair the effects of the present invention, in order to improve handling properties such as slipperiness and winding property and concealability. Examples of such particles include silica, kaolinite, talc, zeolite, alumina, carbon black and the like, and among them, zeolite is preferable. These particles are used alone or in combination of two or more.
[0010]
Further, the white laminated polyester film of the present invention is a white laminated polyester film having a thickness of 50 μm to 500 μm, and the curl value needs to be 2 mm or less. If the curl value is larger than 2 mm, the force for peeling on the bonding surface becomes large, and peeling occurs with the lapse of storage or use time.
[0011]
Further, the white laminated polyester film of the present invention preferably has an apparent density of 1.3 or more. When the ratio is less than 1.3, the feeling of waist is weakened, which is unfavorable for an information recording material used in the present invention.
[0012]
Further, the laminated white polyester-based film of the present invention may have another layer such as a coating layer on one side or both sides as long as the action of the present invention is not impaired. Providing the coating layer can improve the wettability and adhesiveness of the ink and the coating agent. As the compound constituting the coating layer, a polyester-based resin is preferable.In addition, polyurethane resin, polyester urethane resin, acrylic resin, etc., have good wettability and adhesiveness of ordinary polyester film inks and coating agents. It is possible to use compounds and the like used for improvement.
[0013]
Examples of the method for providing the coating layer include methods commonly used such as a gravure coating method, a kiss coating method, a dip method, a spray coating method, a curtain coating method, an air knife coating method, a blade coating method, a reverse roll coating method, and an in-line coating method. Can be applied. As the step of applying, any method such as a method of applying before stretching the film, a method of applying after longitudinal stretching, and a method of applying to the surface of the film after the orientation treatment is possible.
[0014]
The method for producing the white laminated polyester film of the present invention is arbitrary, and is not particularly limited. For example, it can be produced as follows.
[0015]
As a method of laminating the layer A composed of the layer containing the polyester-based resin and the composition containing the white pigment on the layer B composed of the polyester-based resin layer, after supplying the resin of the layer A and the resin of the layer B to separate extruders, A method of simultaneous lamination by a co-extrusion method of laminating in a molten state and extruding from the same die, and a method of laminating a separately formed film can be mentioned. Extrusion is preferred. The lamination may have a three-layer structure such as an A / B / A type.
[0016]
The layer A laminated on the layer B may contain the same or different particles as those contained in the layer B, but the particles contained in the layer B and the layer A laminated on the layer B are different. Is preferred. In particular, when a fluorescent whitening agent or an ultraviolet absorber is contained in the film, or when particles for improving slipperiness or blocking resistance are contained, it is more effective to include them in a layer close to the surface. Therefore, it is preferable to include these in the A layer laminated on the B layer. When particles are contained in the layer A laminated on the layer B, the layer B may not contain particles. The configuration, thickness ratio, lamination method, and the like of each layer are appropriately set within a range that does not impair the operation of the present invention.
[0017]
The unstretched film thus obtained is further stretched between rolls having different speeds (roll stretching), stretched by gripping and expanding with clips (tenter stretching), or stretched by air pressure ( Biaxial orientation treatment is performed by, for example, inflation stretching.
[0018]
As for the conditions for stretching and orienting the unstretched film, it is necessary to have physical properties required for the white laminated polyester film of the present invention. In the present invention, the unstretched film is preferably stretched and oriented by a sequential biaxial stretching method in which the unstretched sheet is stretched in the longitudinal direction and then in the width direction. The sequential biaxial stretching method is performed, for example, as follows.
[0019]
In the first-stage longitudinal stretching step, the film is heated and stretched between two or many rolls having different peripheral speeds (MD magnification). As a heating means at this time, in order to set the temperature of both sides of the unstretched film to different temperatures, by using heating means capable of independently heating, the curl value required for the present invention is set to 2 mm or less. I do. In a conventional unstretched film having a thickness of 50 μm or more used for lamination, the orientation of the front and back sides of the biaxially stretched film is slightly different due to the characteristics of the machine base, and curling has occurred. However, according to the present invention, it is possible to independently control the heating temperature of the front and back sides during longitudinal stretching and to control the orientation state after biaxial stretching by longitudinal stretching performed at different temperatures. Can be minimized. Uniaxially stretched film after stretching is cooled by a cooling roll, a uniaxially stretched film was introduced into a tenter, stretched in 2.5 to 5 times the melting point T _m -10 ° C. below the temperature of the polyester in the width direction.
[0020]
The biaxially stretched film thus obtained is subjected to a heat setting treatment, and if necessary, a 1 to 10% relaxation treatment in the width direction and / or the longitudinal direction. Heat treatment is preferably performed in the range of the melting point T _m -50 ℃ ~T _m polyester in a tenter.
[0021]
The white laminated polyester film of the present invention is used for lamination as a base material for an information recording material such as an IC card such as a magnetic card and a non-contact IC card, and a rewritable card. FIG. 1 schematically shows a cross-sectional view of an example of a non-contact IC card using the white laminated polyester film of the present invention. As shown in FIG. 1, the non-contact IC card (C) includes a card constituent base 1 (1a, 1b), a card constituent base 2 (2), a resin sheet (3), and the resin sheet (3). It comprises an IC chip (4) and an antenna (5) formed thereon. The white laminated polyester film of the present invention is used as a card-forming base material 1 (1a, 1b). As described above, the card-forming base material 1 may be, for example, two layers of A layer / B layer or A layer. It is composed of three layers: layer / layer B / layer A.
[0022]
Next, examples and comparative examples of the present invention will be described. First, measurement and evaluation methods used in Examples and Comparative Examples of the present invention will be described below.
(1) Optical density (OD)
The measurement was performed using a transmission densitometer (Ihac-T5) manufactured by Ihara Electronics Industry Co., Ltd. However, the film thickness was converted to 100 μm.
[0023]
(2) 60 degree gloss (gloss)
The glossiness (gloss) at 60 degrees was measured using a gloss meter (VGS-1001DP) manufactured by Nippon Denshoku Industries.
[0024]
(3) Color b value The color difference was measured using a color difference meter (Z-1001DP) manufactured by Nippon Denshoku. The whiteness of the film was evaluated using the b value (b ₀ ). A larger value indicates a stronger yellow tint.
[0025]
(4) Curl value The film was cut into 100 mm lengthwise and 50 mm widthwise, adjusted for one day under the following four types of environmental conditions, and allowed to stand on a horizontal glass plate with the convex portion of the film facing down. The largest vertical distance between the glass plate and the lower end of the four corners of the raised film was measured using a ruler with a minimum scale of 0.5 mm in units of 0.5 mm, and the average of the measured values at the four points was defined as the curl value. did. Three samples were prepared and repeatedly measured, and the average value was defined as a curl value. (A) -40 ° C, humidity 20%, (b) -40 ° C, humidity 90%, (c) 90 ° C, humidity 20%, (d) 90 ° C, humidity 90%, under four levels of environmental conditions. And left still.
[0026]
(5) Peeling evaluation after lamination The laminated film was left to stand at 70 ° C. in an environment of 90% humidity and visually evaluated as follows.
○ No peeling for 68 hours or more. Peeling occurred in 24 hours to 68 hours. Peeling occurred in 24 hours or less.
【Example】
(Example 1)
(Production of film raw materials)
As a raw material, a mixture of 50% by weight of a polyethylene terephthalate resin having an intrinsic viscosity of 0.62 obtained by a conventional method and 50% by weight of anatase type titanium dioxide particles (TA-300 manufactured by Fuji Titanium Co., Ltd.) having an average particle size of 0.3 μm is mixed. Was supplied to a vented twin-screw extruder to perform preliminary kneading. The molten resin was continuously supplied to a vent-type single-screw kneader, kneaded and extruded, and the obtained strand was cooled and cut to prepare a titanium dioxide-containing master pellet (J).
[0028]
Next, a mixture of 99.3% by weight of a polyethylene terephthalate resin having an intrinsic viscosity of 0.62 and 0.7% by weight of zeolite particles having an average particle size of 0.8 μm was supplied to a vent-type twin-screw extruder and premixed. . This molten resin was continuously supplied to a vent-type single-screw kneader, kneaded and extruded, and the obtained strand was cooled and cut to prepare a zeolite-containing master pellet (K).
[0029]
Next, a mixture of 90% by weight of a polyethylene terephthalate resin having an intrinsic viscosity of 0.62% and 10% by weight of a benzoxazole-based fluorescent whitening agent (OB-1 manufactured by Eastman Chemical Company) was supplied to a vented twin-screw extruder. After the preliminary kneading, the molten resin was continuously supplied to a vent-type single-screw kneader and kneaded to prepare a fluorescent brightener-containing master pellet (L).
[0030]
70% by weight of a polyethylene terephthalate resin having an intrinsic viscosity of 0.62, which was vacuum-dried at 140 ° C. for 8 hours, and 30% by weight of the above titanium dioxide-containing master pellet (J) were pellet-mixed to obtain a film raw material (I). . Further, dried under the same conditions, 68.5% by weight of the zeolite-containing master pellet (K), 30% by weight of the titanium dioxide-containing master pellet (J), and 1.5% by weight of the fluorescent brightener-containing pellet (L) Was mixed with pellets to obtain a film raw material (II).
[0031]
(Preparation of coating liquid)
(Preparation of copolymerized polyester resin)
In a stainless steel autoclave equipped with a stirrer, thermometer and partial reflux condenser, 747 parts by weight of terephthalic acid, 664 parts by weight of isophthalic acid, 202 parts by weight of sebacic acid, 58 parts by weight of fumaric acid, 744 parts by weight of ethylene glycol And 720 parts by weight of neopentyl glycol, and the esterification reaction was carried out from 160 ° C. to 220 ° C. over 3 hours. Next, 0.7 parts by weight of tetra-n-butyl titanate was added, and the temperature was raised from 200 ° C. to 220 ° C. over 1 hour to carry out an esterification reaction. Next, the temperature was raised to 255 ° C., and the pressure in the reaction system was gradually reduced. Thereafter, the reaction was carried out under a reduced pressure of 0.22 mmHg for 1 hour and 30 minutes to obtain a copolymerized polyester resin. The weight average molecular weight of the obtained copolyester resin was 20,000, and the color was light yellow and transparent.
[0032]
(Preparation of self-crosslinkable polyester graft copolymer)
In a reactor equipped with a stirrer, a thermometer, a reflux device and a fixed-rate dropping device, 75 parts by weight of the above-mentioned copolymerized polyester resin, 56 parts by weight of methyl ethyl ketone and 19 parts by weight of isopropyl alcohol were put, and heated and stirred at 65 ° C. Was dissolved. After the resin was completely dissolved, 15 parts by weight of maleic anhydride was added to the polyester solution. Next, a solution prepared by dissolving 10 parts by weight of styrene and 1.5 parts by weight of azobisdimethylvaleronitrile in 12 parts by weight of methyl ethyl ketone was dropped into the polyester solution at 0.1 ml / min, and stirring was further continued for 2 hours. After sampling for analysis from the reaction solution, 5 parts by weight of methanol was added. Next, 300 parts by weight of water and 15 parts by weight of triethylamine were added to the reaction solution, followed by stirring for 1 hour. Thereafter, the reactor internal temperature was raised to 100 ° C., and methyl ethyl ketone, isopropyl alcohol, and excess triethylamine were distilled off to obtain a water-dispersed graft polymer resin (a self-crosslinkable polyester-based graft copolymer). The water-dispersed graft polymer resin was pale yellow and transparent, and had a glass transition temperature of 40 ° C.
[0033]
The self-crosslinkable polyester-based graft copolymer obtained above and ammonium polystyrenesulfonate having a molecular weight of 70,000 (manufactured by NSC Japan) were mixed at a solid content weight ratio of 70/30, and all resin solids were mixed. The concentration was adjusted to 5% by weight, and the solvent was adjusted to a water / isopropyl alcohol = 60/40 weight ratio to obtain an aqueous coating solution.
[0034]
(Preparation of unstretched film)
The above-mentioned film raw materials were supplied to different extruders, and a B layer composed of the raw material (I) and an A layer composed of the raw material (II) were laminated in the order of A layer / B layer / A layer using a feed block. . This was co-extruded from a T-die onto a cooling roll adjusted to 15 ° C. The discharge rate of each extruder was adjusted so that the thickness ratio of each layer was 1: 8: 1, and an unstretched film having a thickness of 1300 μm was prepared.
[0035]
(Preparation of biaxially stretched film)
After heating the unstretched film obtained above with six preheating rolls heated to 75 ° C., between two pairs of nip rolls having different peripheral speeds (low speed roll = 10 m / min, high speed roll = 31 m / min) And stretched longitudinally 3.1 times. At this time, as an auxiliary heating device for the film, an infrared heater (IR rated output: 74 W / cm) having a gold reflective film in the middle of the nip roll was installed at a position 1 cm from the film surface opposite to both surfaces of the film. When cooling the film later, the film surface on the side of the cooling roll was heated at an output of 35% of the rating, and the film surface on the side opposite to the cooling roll was heated at an output of 40% of the rating, and then cooled with the cooling roll. Both sides of the uniaxially stretched film thus obtained were subjected to corona discharge treatment, and the aqueous coating solution obtained above was applied to the treated surface by a reverse roll coating method. Apply a shear rate of 1,000 (1 / second) or more between roll gaps, apply the film to a uniaxially stretched film within 2 seconds, and then dry at 65 ° C, air speed 15 m / second, 2 seconds, 130 ° C, air speed 20 m / second. After drying for 3 seconds to remove water, the uniaxially stretched film was guided to a tenter, stretched 3.8 times in width (horizontal) in a heating section at 140 ° C., fixed in width, heat-treated at 230 ° C., and further heated at 200 ° C. By relaxing at 3.5 ° C. in the width direction by 3.5%, a biaxially stretched white laminated polyester film having a thickness of about 125 μm was obtained.
[0036]
(Example 2)
In Example 1, the preheating roll was changed from 300 mm in diameter to 15 mm, and the number of rolls was further reduced to 10 so that the temperature difference between the front and back was reduced to 1 ° C. or less. A white laminated polyester film was obtained in exactly the same manner as in Example 1, except that
[0037]
(Comparative Example 1)
A white laminated polyester film was obtained in the same manner as in Example 1 except that the output of the infrared heater was changed to 40% on both sides.
[0038]
(Comparative Example 2)
A white laminated polyester film was obtained in the same manner as in Example 1 except that the output of the infrared heater was 35% on both sides.
[0039]
(Comparative Example 3)
A white laminated polyester film was obtained in the same manner as in Example 1 except that the temperature of the preheating roll was 93 ° C. and infrared heating was not performed.
[0040]
The white laminated polyester films of Examples 1 to 3 and Comparative Examples 1 to 3 obtained by the above methods were subjected to a laminating process according to the following formulation, and peeling evaluation and white laminated polyester of the laminated product were performed. The system film was evaluated. Table 1 shows the results.
[0041]
(Film lamination processing)
(Preparation of adhesive)
100 parts by weight of a copolymerized polyester resin containing 70 mol% of terephthalic acid as an acid component (glass transition temperature: 10 ° C.), 2 parts by weight of a trifunctional isocyanate compound composed of an addition reaction product of trimethylolpropane and toluylene diisocyanate, and toluene, A polymer adhesive composition solution comprising 234 parts by weight of a mixed solvent of methyl ethyl ketone was prepared.
[0042]
(Lamination)
The applied amount of the polymer adhesive composition solution was measured to the white laminated polyester film (X) by a die coating method so that the supply thickness of the polymer adhesive composition solution was 120 μm. Drying was performed. In addition, the film surface to which the polymer adhesive composition solution was supplied was measured and applied to the surface in contact with the cooling roll immediately after extrusion during the formation of the white laminated polyester film (X).
[0043]
Subsequently, the same white laminated polyester film (Y) separately prepared was attached to the surface immediately after the drying of the polymer adhesive composition solution, guided between two rolls, and heated and pressed to perform attachment. . In this case, the dry thickness of the intermediate layer composed of the nonwoven fabric sheet and the polymer adhesive composition was 50 μm, and the total thickness of the obtained composite sheet was 300 μm. In addition, the surface of the white laminated polyester film (Y) adhered to the polymer adhesive composition was the surface that was in contact with the cooling roll immediately after extrusion during the formation of the white laminated polyester film (Y).
[0044]
The resulting composite sheet was guided to a calendering device having a pair of rolls capable of heating and pressing. The paired rolls used were both a metal / metal combination whose surfaces were chrome-plated. The roll surface temperature was 150 ° C., and the pressure was 250 kg / cm. The obtained composite sheet was left standing at room temperature of 40 ° C. for 24 hours to perform an aging treatment, and then subjected to the above-mentioned peeling evaluation after cutting into a 100 mm × 100 mm size using an NT cutter.
[0045]
[Table 1]

[0046]
【The invention's effect】
As is clear from Table 1, the films of Examples 1 to 3 satisfying the requirements required in the present invention are white laminated polyester systems having sufficient adhesive durability and sufficient for use in laminating. A film is obtained. On the other hand, the films of Comparative Examples 1 to 3 which do not satisfy the requirements required in the present invention can provide a white laminated polyester film having sufficient adhesion durability to be used for laminating. Absent.
[0047]
[Brief description of the drawings]
FIG. 1 is a cross-sectional view schematically showing an example of a non-contact IC card using a white laminated polyester film of the present invention.
[Explanation of symbols]
C Non-contact IC card 1 Card constituent substrate 1
2 Card component base material 2
3 Resin sheet 4 Antenna 5 IC chip

Claims (5)

A white laminated polyester film in which a white polyester resin layer (A layer) composed of a composition containing a polyester resin and a white pigment is laminated on at least one surface of the polyester resin layer (B layer), A white laminated polyester film for lamination, wherein the thickness of the system film is 50 to 500 μm and the curl value is 2 mm or less. The white laminated polyester film for lamination according to claim 1, wherein the white pigment is titanium oxide. The white laminated polyester film for lamination according to claim 1 or 2, wherein the A layer and / or the B layer contains two or more kinds of particles. The white laminated polyester film for lamination according to any one of claims 1 to 3, wherein the particles contain 100 to 10,000 ppm of a fluorescent whitening agent. The white laminated polyester film for lamination according to any one of claims 1 to 4, wherein the white laminated polyester film is used as a base material of a non-contact IC card.

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