JP2010189573A - Polyester film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyester film capable of expecting application to a solar battery, electronic equipment, further an article related to a life ornament such as a building material, a UV photosensitive marker in an electronic part and optical sensor technology without contaminating the inside of a system at use and given with sufficient discrimination function. <P>SOLUTION: The polyester film is a polyester film having a coating layer on at least one surface, and is characterized in that it contains 1.0-10 wt.% of an organic photochromic compound in the coating layer. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a polyester film having a coating layer colored on at least one surface by irradiation with ultraviolet rays (hereinafter sometimes simply referred to as UV).

  In recent years, functional polyester films have been used in a variety of fields ranging from solar cells, electronic equipment, and other home decorations such as building materials. In addition, a functional polyester film may be used as a mark for decoration or cutting in the production line. In these applications, low-cost, environmentally friendly and highly functional polyester films are desired.

  As an existing polyester film, a polyester film that has been printed by a mainstream inkjet method is known as a building material application for household goods decoration. The problems with the inkjet method are that a large amount of various polymers and pigments are used, so the burden on the environment is large, the size of maintenance such as contamination, capital investment costs, running costs, and production lines When used as a mark, there are technical difficulties such as a need for a drying process, contamination of the process with ink, and changes in film thickness.

  For example, if a polyester film having UV-sensitive coloring performance is used instead of the conventional ink jet method, as a mark in the production line described above, ink is not used, the film thickness is not changed, and coloring is performed during UV irradiation. Can be judged visually, and further, where there is no need for coloring other than in the process, since there is no strong UV light source, it remains transparent, so it can be expected as a new coloring method with high utility value.

  Further examples include not only the possibility of use as a UV photosensitive marker or photosensor technology in electronic parts, but also the possibility of application to beautiful household goods using UV photosensitive coloring technology.

  There are several problems with UV-sensitive colored organic photochromic compound-containing polyesters. For example, an organic photochromic compound may be decomposed by melting of the film or heat (about 300 ° C.) applied during film formation. In addition, the organic photochromic compound may have low dispersibility with respect to inclusion in various methods in the polyester, and in that case, the expected coloring function may not be exhibited. On the other hand, when the organic photochromic compound is blended in a large amount in the polyester with emphasis on the function, the problem of the appearance of the film and the problem of the cost during production occur.

JP 2007-146014 A

  The present invention has been made in view of the above circumstances, and the problem to be solved thereof is that the system does not contaminate the system when it is used, and solar cells and electronic devices, and further related to daily ornaments such as building materials, An object of the present invention is to provide a polyester film having a good identification function, which can be expected to be applied to UV photosensitive markers and optical sensor technology in electronic parts.

  As a result of intensive studies in view of the above circumstances, the present inventor has found that the above problems can be easily solved by a film having a specific configuration, and has completed the present invention.

  That is, the gist of the present invention resides in a polyester film having a coating layer on at least one surface and containing 1.0 to 10% by weight of an organic photochromic compound in the coating layer.

Hereinafter, the present invention will be described in more detail.
The polyester film of the present invention may have a single layer structure or a multilayer structure, and may have a multilayer of 4 layers or more unless the gist of the present invention is exceeded other than the two-layer or three-layer structure. There is no particular limitation.

  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, 1, 4- cyclohexane dimethanol, neopentyl glycol, is mentioned.

  In the polyester film of the present invention, it is preferable to blend particles mainly for the purpose of imparting easy slipping and preventing the occurrence of 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 of the particles include magnesium, kaolin, aluminum oxide, and titanium oxide. Further, heat-resistant organic particles as described in JP-B-59-5216, JP-A-59-217755 and the like may be used. Examples of other heat-resistant organic particles include thermosetting urea resins, thermosetting phenol resins, thermosetting epoxy resins, benzoguanamine resins, and the like. Furthermore, precipitated particles obtained by precipitating and finely dispersing a part of a metal compound such as a catalyst during the polyester production process may 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 0.01-3 micrometers normally, Preferably it is the range of 0.1-2 micrometers. If the average particle size is less than 0.01 μm, the slipperiness may not be sufficiently imparted, or the particles may be aggregated to make the dispersibility insufficient, thereby reducing the transparency of the film. On the other hand, if it exceeds 3 μm, the surface roughness of the film becomes too rough, which may cause problems such as poor film appearance.

  Further, the content of particles in the polyester layer is usually in the range of 0.001 to 5% by weight, preferably 0.005 to 3% by weight. When the particle content is less than 0.001% by weight, the slipperiness of the film may be insufficient. On the other hand, when the content exceeds 5% by weight, the transparency of the film may be insufficient. is there.

  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.

  Also, a method of blending a slurry of particles dispersed in ethylene glycol or water with a vented kneading extruder and a polyester raw material, or a blending of dried particles and a polyester raw material using a kneading extruder. It is done by methods.

  In addition to the above-mentioned particles, conventionally known antioxidants, antistatic agents, thermal stabilizers, lubricants, dyes, pigments, and the like can be added to the polyester film in the present invention as necessary.

  Although the thickness of the polyester film in this invention will not be specifically limited if it can be formed into a film as a film, Usually, 10-350 micrometers, Preferably it is the range of 50-250 micrometers.

  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 of using the polyester raw material described above and cooling and solidifying a molten sheet extruded from a die 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 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 unidirectional stretching is performed in two or more stages may 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.

  For the production of the polyester film of the present invention, a simultaneous biaxial stretching method can also be employed. 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.

  Examples of organic photochromic compounds that can be used in the present invention include organic photochromic substances such as naphthopyran compounds, spirooxazine compounds, 1,4-2H-oxazine, and benzopyran compounds. Among these, spirooxazine compounds And benzopyran compounds are preferred.

  Specific examples of the organic photochromic compound include 1,3,3-trimethylspiro [indoline-2,3 ′-(3H) -naphtho- (2,1-b) (1,4) -oxazine], 6′- Indolino-1,3,3-trimethylspiro [indoline-2,3 ′-(3H) -naphtho- (2,1-b) (1,4) -oxazine], 5-chloro-1,3,3- Trimethylspiro [indoline-2,3 ′-(3H) -naphtho- (2,1-b) (1,4) -oxazine], 6′-piperidino-1,3,3-trimethylspiro [indoline-2, 3 ′-(3H) -naphtho- (2,1-b) (1,4) -oxazine], 1-benzyl-3,3-dimethylspiro [indoline-2,3 ′-(3H) -naphtho- ( 2,1-b) (1,4) -oxazine], 1,3,5,6- Tramethyl-3-ethylspiro [indoline-2,3 ′-(3H) -naphtho- (2,1-b) (1,4) -oxazine], 1,3,3,5,6-pentamethylspiro [indoline] -2,3 '-(3H) -naphtho- (2,1-b) (1,4) -oxazine], 1,3,5,6-tetramethyl-3-ethylspiro [indoline-2,3'- (3H) -pyrido- (3,2-f) (1,4) -benzoxazine], 1,3 ′, 3′-trimethylspiro (2H-1-benzopyran-2,2′-indoline), spiro [ 2H-chromene-2,2′-tricyclo [3.3.1.13.7] decane], 5,7-dimethyl-spiro [2H-chromene-2,2′-tricyclo [3.3.1.13]. .7] decane], and the like.

  Organic photochromic compounds can be used alone, but they have high boiling point solvents, plasticizers, synthetic resins, hindered amine compounds, hinders for the purpose of improving the discoloring function and improving light resistance. It is preferable to use an auxiliary such as a dophenol compound. These compounds are known as materials used in combination with organic photochromic compounds. Examples of aromatic dicarboxylic acids include terephthalic acid and 2,6-naphthalenedicarboxylic acid. Examples of aliphatic glycols include ethylene glycol, Examples include 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, 1, 4- cyclohexane dimethanol, neopentyl glycol, is mentioned.

  Next, the formation method of the coating layer containing the organic photomic compound in this invention is demonstrated. As for the coating layer, it may be provided by in-line coating, which treats the film surface during the stretching process of the polyester film, or may be applied off-system on the film once manufactured, and may employ both offline coating. You may use together. In-line coating is preferably used in that it can be applied at the same time as film formation, and thus can be manufactured at low cost, and the thickness of the coating layer can be changed by the draw ratio.

  The in-line coating is not limited to the following, but for example, in the sequential biaxial stretching, the coating treatment can be performed particularly before the lateral stretching after the longitudinal stretching is finished. When a coating layer is provided on a polyester film by in-line coating, coating can be performed simultaneously with film formation, and the coating layer can be processed at a high temperature, and a film suitable as a polyester film can be produced.

  In the present invention, it is an essential requirement to use an organic photomic compound-containing water / organic solvent mixed solution as a coating solution on one side or both sides of a polyester film, and apply them in-line to form a coating layer. To do. In addition, this coating is not limited by the coating, and if the liquid stability is sufficient when mixed with a coating solution having various functions such as adhesion, it is used with those liquids to provide further performance. Can be provided.

  The coating layer in the present invention is provided for imparting a coloring function by UV irradiation to a polyester film, and other applications include formation of a coating layer that can be expected to have a mark and design performance on the film. .

The structure of the coating liquid which consists of the organic photomic compound containing water / organic solvent mixed solution contained in the coating layer in this invention is demonstrated. Examples of the organic solvent having a certain degree of compatibility with water include alcohols, ketones, and esters. Further, it is desirable to use a small amount of a solvent rich in anthracene such as toluene as a mixed solvent with a solvent of alcohols, ketones or esters. Examples of alcohols include solvents having an alkyl chain typified by ethanol, propanol, isopropanol and the like, alcohols having an aryl group as a substituent, and the like. Examples of ketones include acetone and methyl ethyl ketone. Examples of the esters include ethyl acetate.
Furthermore, it is desirable to perform ultrasonic treatment of the solution if the uniform dispersion of the coating solution or a uniform solution is aimed.

In addition, when the coated layer in the present invention is made into a polyester film and then rolled into a roll, the front and back of the film stick, and so-called blocking is likely to occur. In order to prevent blocking, it is preferable to contain particles. The content of the particles is preferably in the range of 3 to 25%, more preferably in the range of 5 to 15%, and in the range of 5 to 10% in terms of the weight ratio of the entire coating layer. Further preferred. If it is less than 3%, the effect of preventing blocking may be insufficient. On the other hand, when it exceeds 25%, although the blocking prevention effect is high, there is a concern that the transparency of the coating layer is lowered and the coating film strength is lowered due to the loss of the continuity of the coating layer. By using the particles in the above range, it has anti-blocking performance.

  As the particles, for example, inorganic particles such as silica, alumina, and metal oxide, or organic particles such as crosslinked polymer particles can be used. In particular, silica particles are preferred from the viewpoint of dispersibility in the coating layer and transparency of the resulting coating film.

  If the particle size is too small, the effect of preventing blocking is difficult to obtain, and if it is too large, dropping off from the coating film tends to occur. The average particle size is preferably about 1/2 to 10 times the thickness of the coating layer. Furthermore, if the particle size is too large, the transparency of the coating layer may be inferior, so the average particle size is preferably 300 nm or less, and more preferably 150 nm or less. The average particle diameter of the particles described here can be obtained by measuring the 50% average diameter of the number average of the particle dispersion with Microtrac UPA (Nikkiso Co., Ltd.).

  When providing a coating layer by in-line coating, the above-mentioned series of compounds is used as a water / organic solvent mixed solution, and a coating solution adjusted with a solid content concentration of about 0.1 to 50% by weight as a guide is applied onto a polyester film. It is preferable to produce a polyester film having coloring performance in the manner described above. Moreover, in the range which does not impair the main point of this invention, a small amount of organic solvents may be contained in the coating liquid for the purpose of improving dispersibility in water, improving film-forming properties, and the like. Only one type of organic solvent may be used, or two or more types may be used as appropriate.

The film thickness of the coating layer provided on the polyester film of the present invention is usually 0.002~1.0g / ^{m 2,} more preferably 0.005 to 0.5 / ^{m 2,} more preferably 0.01 to 0. The range is ² g / m ² . If the film thickness is less than 0.002 g / m ^2, sufficient UV photosensitive coloring performance may not be obtained, and if it exceeds 1.0 g / m ² , the appearance, transparency, and film blocking properties deteriorate. there's a possibility that.

  In the present invention, as a method for providing the coating layer, a conventionally known coating method such as reverse gravure coating, direct gravure coating, roll coating, die coating, bar coating, curtain coating or the like can be used. Regarding the coating method, there is a description example in “Coating method” published by Yasuharu Harasaki in 1979.

  In the present invention, the drying and curing conditions for forming the coating layer on the polyester film are not particularly limited. For example, when the coating layer is provided by off-line coating, it is usually 3 to 40 at 80 to 200 ° C. The heat treatment may be performed for 2 seconds, preferably 100 to 180 ° C. for 3 to 40 seconds.

  On the other hand, when the coating layer is provided by in-line coating, heat treatment is usually performed at 70 to 280 ° C. for 3 to 200 seconds as a guide.

  Regardless of offline coating or in-line coating, heat treatment and irradiation with active energy rays such as ultraviolet irradiation may be used in combination as required as long as decomposition of the UV-sensitive colored organic photomic compound does not occur. In the present invention, the polyester film constituting the photochromic compound-coated polyester film having color change performance may be subjected to surface treatment such as corona treatment or plasma treatment in advance.

  The content of the organic photomic compound in the coating layer is in the range of 1.0 to 10% by weight. When the content is less than 1.0% by weight, the colorability of the film is inferior. On the other hand, when it contains exceeding 10 weight%, a malfunction arises with the degraded material in a film.

Coloring in the present invention is a color change in the film appearance. Specifically, it can be expressed by the contrast ratio in the luminance measurement. Specifically, the relative luminance obtained from the ratio of the UV irradiated part to the unirradiated part is about 102 to 105, preferably 105 or more. Further, coloring can also be expressed by ΔE obtained from L * a * b * color difference evaluation, and the ΔE value is preferably about 5.0 to 20.0, more preferably 20.0 or more. is there.

  According to the polyester film of the present invention, it is possible to provide a photochromic compound-coated polyester film having high transparency and color change performance even when an organic photomic compound is contained in the coating layer within an appropriate amount range. In addition, the polyester film of the present invention can be used as a mark for a production line instead of a method such as inkjet, and can be used as a UV photosensitive marker or photosensor technology in electronic parts. Its industrial value is high because it can be expected to be applied to beautiful household goods using light-emitting technology.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to a following example, unless the summary is exceeded. The measurement method and evaluation method used in the present invention are as follows.

(1) Transmittance measurement of a polyester film As a reference | standard of transparency, evaluation of transparency by visual observation and transmittance | permeability measurement are mentioned. Judgment is based on the following criteria.
-Regarding visual observation ○: Almost transparent △: Transparent, but slightly colored yellow ×: Yellow is strongly cloudy-Regarding transmittance measurement Integrating sphere manufactured by Nippon Denshoku Industries Co., Ltd. according to JIS-K7105 The total light transmittance of the film was measured with a turbidimeter NDH-300A. The transmittance decrease in the range of 0.5 to 1% with respect to the transmittance of a general polyester film is ◎, the transmittance decrease in the range of 1-2% is ○, and the range of 2 to 4% The decrease in transmittance was evaluated as Δ, and the decrease in transmittance exceeding 4% was evaluated as x.

(2) Contrast evaluation of coloring strength after UV irradiation of polyester film Using a luminance meter, the contrast ratio between the non-colored portion of the film before UV irradiation and the colored portion after UV irradiation was evaluated. Specifically, a sample is placed on a flat illuminator manufactured by Dentsu Sangyo Co., Ltd .: HF-SL-A48LCF, and further, using Konica Minolta Sensing Co., Ltd .: CS-200, the measurement viewing angle is 1 °, and the distance between the sample and the luminance meter is measured. The luminance value (cd / m ² ) was measured at 500 mm. The relative luminance (%) was obtained from the following formula.

Relative luminance = (measured value of UV non-irradiated part) ÷ (measured value of UV irradiated part) × 100
The relative luminance was evaluated according to the following criteria from the obtained relative luminance value.

A: More than 105 (strong coloring)
○: 102 to 105 (colored)
Δ: 101-102 (lightly colored)
X: Less than 101 (almost not colored)

(3) L * a * b * Color Difference Evaluation of Coloring Strength after UV Irradiation of Polyester Film About the obtained polyester film after UV irradiation, using a color difference meter, uncolored portions of the film before UV irradiation and UV irradiation The L * a * b * color difference of the later colored portion was evaluated. Specifically, according to JIS Z 8729, the L * a * b * color difference values of the UV irradiated portion and the non-irradiated portion were measured using a color difference meter CR-410 (sample diameter 50 mm) manufactured by Konica Minolta. At this time, the light source was C / D65, the back surface was white, and measurement was performed by a reflection method. The measurement was performed three times, and an average value was adopted. ΔL * (irradiated portion L * value−non-irradiated portion L * value), Δa * (irradiated portion a * value−non-irradiated portion a * value), Δb * (irradiated portion b * value−non-irradiated portion) (Part b * value) was calculated, and ΔE value was calculated and evaluated.
The ΔE value was determined from the following formula.

ΔE = {(ΔL *) ² + (Δa *) ² + (Δb *) ² } ^1/2
Evaluation was performed based on the following criteria from the obtained ΔE value.

A: More than 20.0 (strong coloring)
○: 10.0 to 20.0 (colored)
Δ: 5 to 10.0 (light coloring)
X: Less than 5 (almost not colored)

(4) Visual Evaluation of Coloring Strength of Polyester Film after UV Irradiation In the polyester film having irreversible color change (coloring) performance by UV, the present invention aims at industrial production in the future and changes visually. Since the first condition is that it can be seen, the obtained polyester film after UV irradiation was visually evaluated for strength. Judgment is based on the following criteria.
◎: Strong coloring ○: Colored △: Light color ×: Not colored

The polyester used in the examples and comparative examples was prepared as follows.
<Method for producing polyester (A)>
Using 100 parts by weight of dimethyl terephthalate and 60 parts by weight of ethylene glycol as starting materials, adding tetrabutoxy titanate as a catalyst to the reactor, setting the reaction start temperature to 150 ° C., and gradually increasing the reaction temperature as methanol is distilled off. It was 230 degreeC after 3 hours. After 4 hours, the transesterification reaction was substantially completed, and then a polycondensation reaction was performed for 4 hours.
That is, the temperature was gradually raised from 230 ° C. to 280 ° C. On the other hand, the pressure was gradually reduced from normal pressure, and finally 0.3 mmHg. After the start of the reaction, the reaction was stopped at a time corresponding to an intrinsic viscosity of 0.63 due to a change in stirring power of the reaction vessel, and the polymer was discharged under nitrogen pressure to obtain a polyester (A) having an intrinsic viscosity of 0.63.

<Method for producing polyester (B)>
Starting from 100 parts by weight of dimethyl terephthalate and 60 parts by weight of ethylene glycol, magnesium acetate / tetrahydrate is added as a catalyst to the reactor, the reaction start temperature is set to 150 ° C., and the reaction temperature is gradually increased as methanol is distilled off. Was raised to 230 ° C. after 3 hours. After 4 hours, the transesterification reaction was substantially terminated. This reaction mixture was transferred to a polycondensation tank, orthophosphoric acid was added, and germanium dioxide was added to carry out a polycondensation reaction for 4 hours. That is, the temperature was gradually raised from 230 ° C. to 280 ° C. On the other hand, the pressure was gradually reduced from normal pressure, and finally 0.3 mmHg. After the start of the reaction, the reaction was stopped at a time corresponding to an intrinsic viscosity of 0.65 due to a change in stirring power in the reaction vessel, and the polymer was discharged under nitrogen pressure to obtain a polyester (B) having an intrinsic viscosity of 0.65.

<Method for producing polyester (C)>
In the production method of polyester (A), 0.2 parts of silica particles having an average particle diameter of 2.0 μm dispersed in ethylene glycol were added, and the polycondensation reaction was stopped at a time corresponding to an intrinsic viscosity of 0.66. A polyester (C) having an intrinsic viscosity of 0.66 was obtained using a method similar to the method for producing polyester (A).

Example 1:
A mixed raw material obtained by mixing polyesters (A), (B), and (C) at a ratio of 85%, 5%, and 10%, respectively, is used as a raw material of the outermost layer (surface layer), and polyesters (A) and (B) are each 95 %, 5% mixed raw materials were used as intermediate layer raw materials, each was supplied to two extruders, melted at 290 ° C, and then on a cooling roll set at 40 ° C. It was coextruded with a layer structure of a layer (surface layer / intermediate layer / surface layer) and cooled and solidified to obtain an unstretched sheet. Next, the film was stretched 3.4 times in the machine direction at a film temperature of 85 ° C. using the difference in peripheral speed of the roll, and 50 parts by weight of the following resin I having an easy adhesion function was added to one side of the machined film. A spirooxazine compound which is an organic photochromic compound, 1,3,3-trimethylspiro in a mixed solution of water and ethanol (mixing ratio is 4: 6) containing 45 parts by weight and 5 parts by weight of inert particles III A coating solution containing [indoline-2,3 ′-(3H) -naphtho- (2,1-b) (1,4) -oxazine] was applied, led to a tenter, and 4.20 ° C. in the lateral direction. Stretched 0 times, heat treated at 225 ° C., relaxed 2% in the transverse direction, and 1,3,3-trimethylspiro [indoline-2,3 ′-(3H) -naphtho in the coating layer after drying -(2,1-b) (1,4) -oxazine] to 9 A polyester film containing 0.8% by weight and having a thickness of 100 μm (surface layer: 5 μm, intermediate layer: 90 μm) was obtained. The obtained polyester film was a colorless and transparent film. The polyester film is irradiated with UV light (181 mW / cm ² , 10 m / min, d = 100 mm) using a high-pressure mercury lamp (Ushio Electric Co., Ltd .: UVC-402 / 1HN: 302 / 1MN: JC01) to achieve color change performance. As a result of evaluation, the change to the yellow colored state was satisfactory.

-Contents of coating agent Binder resin I: Copolyester water-soluble resin II containing terephthalic acid, isophthalic acid, 5-sodium sulfoisophthalic acid as dicarboxylic acid components, and ethylene glycol and diethylene glycol as diol components II: Saponification Polyvinyl alcohol inert particles III having a degree of polymerization of 88 mol% and a degree of polymerization of 1700: silica sol having an average particle diameter of 0.05 μm

Example 2:
A coating solution in which the blending amount of 1,3,3-trimethylspiro [indoline-2,3 ′-(3H) -naphtho- (2,1-b) (1,4) -oxazine] is 1.2 wt% This is the same method as in Example 1 except that a polyester film is obtained. The obtained polyester film was a colorless and transparent film. The polyester film was subjected to UV irradiation in the same manner as in Example 1 to evaluate the color change (coloring) performance. As a result, the change to the yellow colored state was satisfactory. It was in a light yellow colored state (strength), and the transparency was also good.

Comparative Example 1:
Using a coating solution in which the amount of 1,3,3-trimethylspiro [indoline-2,3 ′-(3H) -naphtho- (2,1-b) (1,4) -oxazine] is 20 wt% The method is the same as in Example 1 except that a polyester film is obtained. The obtained polyester film was a yellow film that lost transparency. The polyester film was subjected to UV irradiation in the same manner as in Example 1 to evaluate the color change (coloring) performance. As a result, the change to a yellow colored state was significant.

Comparative Example 2:
A coating solution in which the blending amount of 1,3,3-trimethylspiro [indoline-2,3 ′-(3H) -naphtho- (2,1-b) (1,4) -oxazine] is 0.5 wt% This is the same method as in Example 1 except that a polyester film is obtained. The obtained polyester film was a transparent film. The polyester film was irradiated with UV in the same manner as in Example 1, and the color change (coloring) performance was evaluated. As a result, no change to a yellow colored state could be confirmed.

  The polyester film of the present invention can be used as a measure of ultraviolet intensity measurement in various applications such as building materials for outdoor use, and can be used as a UV photosensitive marker or optical sensor technology in electronic parts. Expected to be applied to beautiful household goods using photosensitive coloring technology.

Claims (1)

A polyester film having a coating layer on at least one surface, wherein the coating layer contains an organic photochromic compound in an amount of 1.0 to 10% by weight.