JP5363830B2 - Luminescent 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 luminous 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 at least one kind of compound selected from a polycyclic aromatic hydrocarbon based compound and a porphyrin based compound in the coating layer. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

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

  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, running costs, and production lines When used as a mark, there are technical difficulties such as the 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 light-emitting 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 visually determined in the form of luminescence, and further, where there is no need for coloring except for the process, it remains transparent because there is no strong UV light source, so it can be expected as a novel coloring method with high utility value. Further examples include not only the possibility of use as a UV photosensitive marker and optical sensor technology in electronic parts, but also the possibility of application to beautiful household goods using the UV photosensitive coloring technology.

  Therefore, if a certain kind of light-emitting organic compound can be contained in the polyester film itself, it becomes a method for providing a new delineated polyester film in place of the ink jet method. However, there are several problems with polyesters containing UV-sensitive luminescent organic compounds. For example, a UV-sensitive organic light-emitting compound may be decomposed due to melting of the film or heat (about 300 ° C.) applied during film formation. In addition, UV-sensitive light-emitting organic compounds may have low dispersibility with respect to inclusion in various methods such as coating and kneading on polyester, and in that case, the expected coloring function may not be exhibited. . On the other hand, when emphasizing the function and blending a large amount of the UV-sensitive organic light-emitting compound with the polyester, problems of the appearance of the film and the cost of 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 is a polyester film having a coating layer provided on at least one surface by in- line coating. In the coating layer, 1.0 to 10% by weight of an anthracene compound, a copolyester, The present invention resides in a luminescent polyester film characterized by containing polyvinyl alcohol and particles .

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 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 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.

  In the present invention, the coating layer needs to contain at least one compound selected from polycyclic aromatic hydrocarbon compounds and porphyrin compounds. These compounds are UV-sensitive organic compounds, and specific examples include anthracene, 9,10-diphenylanthracene, dibenzoanthracene, 1,5-diphenylnaphthalene, 1,5-diaminonaphthalene, porphyrin, and these compounds. And derivatives and analogs thereof. Among these, anthracene compounds such as anthracene and 9,10-diphenylanthracene are preferable.

  Next, the formation method of the coating layer 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 essential that one side or both sides of the polyester film have a UV-sensitive luminescent organic compound-containing water / organic solvent mixed solution as a coating solution and apply in-line coating to form a coating layer. It is a requirement. 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 light emitting function by UV irradiation to a polyester film, and other applications include formation of a coating layer that can be expected to have marks and design performance on the film. .

  The structure of the coating solution composed of the UV-sensitive luminescent organic compound-containing water / organic solvent mixed solution contained in the coating layer in the present invention will be described. 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, when aiming at uniform dispersion of the coating solution or a uniform solution, it is desirable to perform ultrasonic treatment of the solution.

Moreover, when it rolls after forming into a polyester film in the coating layer in this invention, the front and back of a film stick, and what is called blocking becomes easy 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 luminous 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 light-sensitive emission 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, as long as decomposition of the UV light-sensitive organic compound does not occur, heat treatment and irradiation with active energy rays such as ultraviolet irradiation may be used in combination. The polyester film constituting the UV-sensitive organic compound-coated polyester film in the present invention may be subjected to surface treatment such as corona treatment or plasma treatment in advance.

  The content of the UV light-sensitive organic 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 light emission 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.

  In the present invention, light emission is classified into fluorescence upon UV irradiation. Specifically, an electron of an organic compound contained in the film absorbs the energy of the UV light and is excited to a first electronic excited state. Light emitted when returning to the ground state. That is, in the present invention, it is a color change at the time of UV irradiation in the appearance of the polyester film having this phenomenon. In the appearance of the polyester film, the polyester film that is transparent before UV irradiation is subjected to UV irradiation while only the UV irradiation portion is blue. It means to show luminescence.

  According to the polyester film of the present invention, it is possible to provide a UV-sensitive luminescent polyester film having high transparency even when the UV-sensitive luminescent organic compound is contained in an appropriate amount within the coating layer. 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 strong and cloudy

-Regarding transmittance measurement In accordance with JIS-K7105, the total light transmittance of the film was measured with an integrating sphere turbidimeter NDH-300A manufactured by Nippon Denshoku Industries Co., Ltd. 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) Luminous evaluation The luminous intensity during UV irradiation of the polyester film was visually evaluated according to the following criteria.
◎: Strong light emission ○: Light emission △: Light emission ×: No light emission

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 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 coating solution containing 45 parts by weight and 5 parts by weight of inert particles III and containing an anthracene compound, which is a luminescent organic compound, in a mixed solution of water and ethanol (mixing ratio is 4: 6) is applied. The film was stretched 4.0 times at 120 ° C. in the transverse direction, heat treated at 225 ° C., then relaxed 2% in the transverse direction, and the coating layer after drying contains 9.8% by weight of an anthracene compound. A polyester film 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 was 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), and the light emission performance was visually observed. As a result of evaluation, a remarkable change to a blue light emission state was observed.

-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:
The method is the same as that of Example 1 except that a polyester film is obtained using a coating solution with an anthracene content of 1.2 wt%. The obtained polyester film was a colorless and transparent film. The polyester film was irradiated with UV in the same manner as in Example 1, and the light emission performance was visually evaluated. As a result, a change to a blue light emission state was observed.

Comparative Example 1:
The method is the same as in Example 1 except that a polyester film is obtained using a coating solution in which the anthracene content is 20 wt%. The obtained polyester film was a white film lacking in transparency. The polyester film was subjected to UV irradiation in the same manner as in Example 1, and the light emission performance was visually evaluated. As a result, a marked change to a blue light emission state was observed.

Comparative Example 2:
The method is the same as in Example 1 except that a polyester film is obtained using a coating solution in which the amount of anthracene is 0.5 wt%. The obtained polyester film was a colorless and transparent film. The polyester film was irradiated with UV in the same manner as in Example 1, and the light emission performance was visually evaluated. As a result, almost no change to the blue light emission state was observed.

  The organic compound-coated UV light-sensitive transparent polyester film of the present invention can be used as a mark for a production line instead of an inkjet method or the like, and can be used as a UV light-sensitive marker or photosensor technology in electronic parts. In addition to this, it can be expected to be applied to beautiful daily necessities using UV-sensitive light-emitting technology.

Claims (1)

A polyester film having a coating layer provided on at least one surface by in- line coating , and containing 1.0 to 10% by weight of an anthracene compound, copolymer polyester, polyvinyl alcohol, and particles in the coating layer. luminescent polyester film, characterized in that.