KR102501654B1 - Hydrophilic polyester film and manufacturing method thereof - Google Patents

Abstract

The present invention relates to a hydrophilic polyester film having excellent durability capable of maintaining hydrophilicity for a long time under various conditions of use and a method for manufacturing the same, which enables strong chemical bonding between the polyester film and the hydrophilic material even when manufactured in an in-line process. To this end, a polyester film and a hydrophilic layer on at least one surface thereof, but the hydrophilic layer provides a hydrophilic polyester film having a water contact angle of 30 degrees or less.

Description

Hydrophilic polyester film and its manufacturing method {HYDROPHILIC POLYESTER FILM AND MANUFACTURING METHOD THEREOF}

The present invention relates to a durable hydrophilic polyester film that maintains hydrophilicity for a long time under various conditions of use by enabling strong chemical bonding between the polyester film and a hydrophilic material when the hydrophilic film is manufactured in an in-line process.

In general, medical diagnostic strips or face shields, face shields, eyewear such as goggles or glasses, car window shields or windows, glass windows of buildings, polymer films used in greenhouses, bathroom mirrors, food packaging materials that require transparency, etc. Anti-fogging treatment is required.

In this regard, Korean Patent Publication No. 10-2019-0006182 and Korean Patent Registration No. 10-0989411 apply a hydrophilic polymer material having an ionic group or polymerize under ultraviolet and heat conditions by using a combination of monomers having a hydrophilic functional group. Methods that exhibit hydrophilic properties by reacting are mainly used.

However, the above-described method is relatively advantageous in terms of hydrophilic function and durability because it is manufactured through a separate coating process using an already manufactured film as a substrate, especially when using a film, but it is not preferable because of problems such as cost increase.

In order to solve this economic problem, it is required to perform the coating process in-line. In this regard, Korean Patent Publication Nos. 10-2020-0031040 and 10-2019-0030619 and US Patent Registration US 7,700,187 have several constraints for in-line manufacturing of a layer having hydrophilic properties. Due to limitations, it is difficult to secure sufficient binding force with the polymer film. After the water film is formed, the hydrophilic film layer is peeled off in the process of drying or removing it, making it difficult to use it several times for a long period of time. There is a problem that can dissolve together and cause denaturation of the sample.

Therefore, there is an urgent need to develop a durable hydrophilic polyester film that maintains hydrophilicity for a long time under various conditions of use by enabling strong chemical bonding between the polyester film and the hydrophilic material when producing the hydrophilic film in an in-line process.

Korean Patent Publication No. 10-2019-0006182 Korean Patent Registration No. 10-0989411 Korean Patent Publication No. 10-2020-0031040 Korean Patent Publication No. 10-2019-0030619 US registered patent US7,700,187

The present invention has been made to solve the above-mentioned problems, and the problem to be solved by the present invention is to enable strong chemical bonding between the polyester film and the hydrophilic material when manufacturing the hydrophilic film in an in-line process, even under various conditions of use. It is intended to provide a durable hydrophilic polyester film that maintains hydrophilicity for a long time and a manufacturing method thereof.

The above and other objects and advantages of the present invention will become apparent from the following description of preferred embodiments.

The above object includes a polyester film and a hydrophilic layer on at least one surface thereof, wherein the hydrophilic layer has a water contact angle of 30 degrees or less,

The hydrophilic layer satisfies Equation 1 below,

(Equation 1)

0.50< I _{1340 cm-1} /I _{1409 cm-1} <1.30

Here, I is the height of the absorbance peak at each wave number in the FTIR spectrum measured by the ATR method, and is achieved by the hydrophilic polyester film.

Here, the hydrophilic layer is coated with a hydrophilic coating solution comprising at least one organic hydrophilic material selected from epoxy polyol and polyethylene oxide, at least one inorganic hydrophilic material selected from silica, alumina and titanium oxide, an organic siloxane compound, a polyamine-based crosslinking agent, and a surfactant. may have been

Preferably, the organosiloxane compound may be a siloxane compound having a reactive group of at least one of an epoxy group, an amino group, and an ethylene group.

Preferably, the organosiloxane compound is 3-glycidoxypropylaminotrimethoxysilane, 3-glycidoxypropylaminotriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-(meth)acryloyltrimethoxysilane or 3-(meth)acryloyltriethoxysilane.

Preferably, it may include 0.5 to 5 parts by weight of an organic hydrophilic material, 0.5 to 10 parts by weight of an inorganic hydrophilic material, 0.5 to 5 parts by weight of an organosiloxane compound, and 0.15 to 1.0 parts by weight of a surfactant per 100 parts by weight of the hydrophilic coating solution. .

Preferably, the polyvalent amine-based crosslinking agent may include 10 to 30 parts by weight per 100 parts by weight of the organic hydrophilic material.

Preferably, the surfactant may be an ionic surfactant or a nonionic surfactant.

Preferably, the thickness of the hydrophilic layer may be 10 nm to 200 nm.

Preferably, it may have a chemical bond of at least one of a silicon ether bond, an amide bond, and an ether bond between the hydrophilic layer and the polyester film.

Preferably, the hydrophilic layer may have a change in water contact angle of less than 5 degrees after wiping the water film layer formed on the surface 5 times or more when exposed to a hot water bath at 80 ° C. for 1 minute.

Preferably, the hydrophilic layer may have a change in water contact angle of less than 5 degrees after being placed in an oven at 47° C. and allowed to stand for 30 days.

In addition, the above object, the first step of producing a polyester sheet from a polyethylene terephthalate chip from which moisture is removed, and a polyester film uniaxially stretched by stretching the polyester sheet 3 to 5 times in the machine direction (MD) The second step of manufacturing, the third step of applying a hydrophilic coating solution on the uniaxially stretched polyester film, and the uniaxially stretched polyester film coated with the hydrophilic coating solution are stretched 3 to 5 times in the transverse direction (TD) A fourth step of preparing a biaxially stretched polyester film, a fifth step of heat-treating the biaxially stretched polyester film at 230 to 250 ° C, and heat-setting the heat-treated polyester film at 200 to 220 ° C. It is achieved by a method for producing a hydrophilic polyester film comprising 6 steps.

In addition, the above object is a first step of manufacturing a polyester sheet from a polyethylene terephthalate chip from which moisture has been removed, a second step of applying a hydrophilic coating solution on the polyester sheet, and a polyester sheet coated with a hydrophilic coating solution. The third step of preparing a uniaxially stretched polyester film by stretching 3 to 5 times in the machine direction (MD), and the uniaxially stretched polyester film coated with a hydrophilic coating solution is stretched 3 to 5 times in the transverse direction (TD) A fourth step of preparing a biaxially stretched polyester film by stretching, a fifth step of heat-treating the biaxially stretched polyester film at 230 to 250 ° C, and heat-setting the heat-treated polyester film at 200 to 220 ° C. It is achieved by a method for producing a hydrophilic polyester film comprising the sixth step.

Preferably, the hydrophilic coating solution may be a mixture of a surfactant, an organosiloxane, an organic hydrophilic material, an inorganic hydrophilic material, and a polyvalent amine-based crosslinking agent in order.

Preferably, the hydrophilic coating solution is hydrolyzed at pH 2 to 5 by adding a surfactant and organosiloxane, and then the pH is adjusted to 8 to 10 by additionally mixing organic hydrophilic substances, inorganic hydrophilic substances, and a digamine-based crosslinking agent. can

Preferably, the organic hydrophilic material may be at least one of epoxy polyol and polyethylene oxide.

Preferably, the inorganic hydrophilic material may be at least one of silica, alumina and titanium oxide.

According to the hydrophilic polyester film according to the present invention, even when manufactured in an in-line process, a strong chemical bond between the polyester film and the hydrophilic material is possible, and as a result, it has excellent durability capable of maintaining hydrophilicity for a long time under various conditions of use. It works.

However, the effects of the present invention are not limited to the effects mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the description below.

1 is an ATR-FTIR spectrum of a hydrophilic polyester film according to Example 1 and Comparative Example 1 of the present invention.

With reference to the accompanying drawings, embodiments of the present invention will be described in detail so that those skilled in the art can easily carry out the present invention. However, the present invention may be embodied in many different forms and is not limited to the embodiments described herein.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. In case of conflict, the present specification, including definitions, will control. Also, although methods and materials similar or equivalent to those described herein may be used in the practice or testing of the present invention, suitable methods and materials are described herein.

Hereinafter, the present invention will be described in detail.

A hydrophilic polyester film according to one aspect of the present invention includes a polyester film and a hydrophilic layer on at least one surface thereof, but the hydrophilic layer has a water contact angle of 30 degrees or less. At this time, the hydrophilic layer has a water contact angle of 30 degrees or less, more preferably 20 degrees or less. When the water contact angle is higher than 30 degrees, sufficient hydrophilicity is not exhibited at the time of application to various products.

The present invention has tried to solve the problem of lack of durability due to lack of binding force when manufacturing a hydrophilic polyester film in an in-line process, and as a result, it was confirmed that it can be solved by selective chemical bonding between the polyester film and a hydrophilic material, thereby completing the invention. It became. That is, it was confirmed that the hydrophilic polyester film according to an embodiment of the present invention is expressed when the condition of Equation 1 below is satisfied by a specific bond between the polyester film and the hydrophilic material constituting the hydrophilic layer, and the present invention has completed

In one embodiment, the hydrophilic layer preferably satisfies Equation 1 below.

(Equation 1)

0.50< I _{1340 cm-1} /I _{1409 cm-1} <1.30

Here, I is the height of the absorbance peak at each wave number in the FTIR spectrum measured by the ATR method.

Therefore, Equation 1 represents the ratio of absorbance peaks at wave numbers 1340cm ^-1 and 1409cm ^-1 in the FTIR-ATR analysis spectrum.

More specifically, the polyester film is manufactured through simultaneous or timed biaxial stretching, and in this process, the polymer chains in the film undergo crystallization to a certain extent, exhibiting properties such as excellent transparency and strength. Such a polyester film is a stable ester Since it is made up of bonds, it shows excellent chemical resistance, but this means that it is difficult to form bonds with other materials. In general, the polyester film has a characteristic peak in the ATR-FTIR spectrum as shown in Figure 1, and in particular, the absorbance peak due to the out-of-plane mode of the benzene ring is seen at 1409 cm ^-1 , and the absorbance peak is the crystallinity of the film. The absorbance peak, which is independent of and directly changes depending on the crystallinity of the film, comes from or near 1340 cm ^-1 , and since the crystallinity increases, the absorbance peak at or near 1340 cm ^-1 is an indicator of the crystallinity of the film. can be used as In addition, in order for the polyester film to undergo chemical bonding, the polymer chain must first be decomposed and reacted with another material or a simultaneous substitution reaction must be performed. At this time, when the polymer chain is broken or substituted with another material, the crystallinity of the film decreases, and thus the absorbance at 1340 cm ^-1 decreases.

According to the present invention, a certain amount or more of chemical bonding proceeds between the polyester film and the hydrophilic layer including the hydrophilic material, so that the (height) ratio of the absorbance peaks at 1340 cm ^-1 and 1409 cm ^-1 in the ATR-FTIR spectrum is greater than 0.5 and less than 1.3. When in the range, it is possible to implement a hydrophilic polyester film having sufficient durability. At this time, when the absorbance peak ratio is 0.5 or less, the polymer chain of the polyester film is decomposed too much to lose excellent properties inherent in the film, and when it is 1.3 or more, sufficient chemical bonding does not proceed, resulting in unsatisfactory durability.

In one embodiment, the hydrophilic layer includes at least one organic hydrophilic material selected from epoxy polyol and polyethylene oxide, at least one inorganic hydrophilic material selected from silica, alumina, and titanium oxide, an organic siloxane compound, a polyamine-based crosslinking agent, and a surfactant. It may be coated with a coating liquid.

In general, there are many limitations in implementing a hydrophilic coating composition in an in-line process compared to an offline process. For example, in the case of an in-line process, since coating is performed simultaneously in the process of manufacturing a polyester film, there are many limitations in selecting a hydrophilic material or solvent, and it is difficult to create a sufficiently strong bond between the polyester film and the hydrophilic material. There are existing products with in-line coating applied, but since they are mainly laminated through weak chemical bonds such as hydrogen bonding or Van der Waals bonding between the coating layer and the polyester film, the conditions in which the hydrophilic film is used, such as high temperature and high humidity, A water film is formed on the surface of a film, such as fogging that occurs in a liquid or in cold weather, and in the process of removing it, the coating layer is washed together. This is because of the lack of chemical bonds.

Accordingly, the present inventors have developed a hydrophilic polyester film capable of forming sufficiently strong chemical bonds even in an in-line process, and durability is improved by coating a coating solution containing the components of the above-described hydrophilic coating solution and having the pH adjusted in an in-line process. A hydrophilic polyester film was completed.

In one embodiment, in the hydrophilic coating solution, at least one reactive organic hydrophilic material such as epoxy polyol and polyethylene oxide and at least one reactive inorganic hydrophilic material such as silica, alumina, and titanium oxide may be used alone or in combination. . It is preferable to include 0.5 to 5 parts by weight of an organic hydrophilic material and 0.5 to 10 parts by weight of an inorganic hydrophilic material per 100 parts by weight of the entire hydrophilic coating solution. At this time, when the amount is less than the preferred range, it is difficult to obtain the desired hydrophilic properties, and when the amount is used more than the range, the preparation of the coating solution is unstable and is not preferable in terms of economy.

In one embodiment, the organic siloxane compound in the hydrophilic coating solution is preferably a siloxane compound having at least one reactive group among an epoxy group, an amino group, and an ethylene group. Organosiloxane is a material that induces strong chemical bonding by acting as a bridge between a polyester film and a hydrophilic material, specifically, 3-glycidoxypropylaminotrimethoxysilane, 3-glycidoxypropylaminotriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-(meth)acryloyltrimethoxysilane, 3-(meth)acryloyltriethoxysilane and the like can be used. It is preferable to include 0.5 to 5 parts by weight of the organic siloxane compound per 100 parts by weight of the total hydrophilic coating solution. At this time, when used in less than 0.5 parts by weight, sufficient chemical bonding is not generated, and if it exceeds 5 parts by weight, it is not preferable for the hydrophilic film required in the present invention due to the hydrophobic nature of organosiloxane.

In one embodiment, a polyamine-based crosslinking agent containing two or more amine groups in the hydrophilic coating solution is added for excellent durability. In particular, when using epoxy polyol as a hydrophilic material, it is preferable to use 10 to 30 parts by weight per 100 parts by weight of epoxy polyol. At this time, if it is less than 10 parts by weight, it is difficult to obtain sufficient durability, and if it exceeds 30 parts by weight, it is not preferable to implement hydrophilic properties.

In one embodiment, the surfactant in the hydrophilic coating solution is a material added to improve stability and wetting properties of the coating solution. As such a surfactant, an ionic surfactant or a nonionic surfactant may be used, and it is preferable to use 0.15 to 1.0 parts by weight per 100 parts by weight of the hydrophilic coating solution.

In one embodiment, the hydrophilic coating solution is preferably a mixture of a surfactant, an organic siloxane, an organic hydrophilic material, an inorganic hydrophilic material, and a polyvalent amine-based crosslinking agent in order. In addition, the hydrophilic coating solution is preferably adjusted to a pH of 8 to 10 by adding a surfactant and an organosiloxane to hydrolyze at pH 2 to 5, and then mixing an organic hydrophilic material, an inorganic hydrophilic material, and a digamine-based crosslinking agent. In this way, even if the pH is not adjusted step by step, a chemical bond is formed to some extent, but it is not enough to secure sufficient durability, so it is preferable to adjust the pH step by step.

In one embodiment, it is characterized in that a strong chemical bond is formed between the hydrophilic layer and the polyester film, and specifically, it may have at least one chemical bond among a silicone ether bond, an amide bond, and an ether bond. The presence or absence of such a chemical bond can be confirmed by XPS (X-ray Photoelectron Spectroscopy) analysis.

In one embodiment, the thickness of the hydrophilic layer is preferably 10 nm to 200 nm. This is because when the thickness of the hydrophilic layer is less than 10 nm, there is a disadvantage in not exhibiting sufficient hydrophilicity, and when it exceeds 200 nm, it is difficult to manufacture in-line due to the thickness and economically disadvantageous.

In one embodiment, the hydrophilic layer may have a change in water contact angle within 5 degrees after wiping the water film layer generated on the surface 5 times or more when exposed to a hot water bath at 80 ° C for 1 minute. This makes it possible to provide a hydrophilic polyester film with excellent durability.

In one embodiment, the hydrophilic layer may have a change in water contact angle within 5 degrees after being placed in an oven at 47° C. and left standing for 30 days. This makes it possible to provide a hydrophilic polyester film having excellent durability at high temperatures.

A method for producing a hydrophilic polyester film according to another aspect and another aspect of the present invention is characterized in that the above-described hydrophilic coating liquid is prepared by in-line coating, and the order of coating is uniaxially stretching the polyester film in the longitudinal direction and then the hydrophilic coating liquid It may be biaxially stretched by coating and then stretched in the transverse direction, or biaxially stretched in the longitudinal and transverse directions after coating a hydrophilic coating solution on an unoriented polyester sheet.

More specifically, the method for producing a hydrophilic polyester film according to another aspect of the present invention includes the first step of preparing a polyester sheet from a polyethylene terephthalate chip from which moisture is removed, and the polyester sheet in a machine direction (MD) in three The second step of preparing a uniaxially stretched polyester film by stretching ~5 times, the third step of applying the above-described hydrophilic coating solution on the uniaxially stretched polyester film, and the uniaxially stretched polyester film coated with the hydrophilic coating solution. A fourth step of preparing a biaxially stretched polyester film by stretching the polyester film 3 to 5 times in the transverse direction (TD), and a fifth step of heat-treating the biaxially stretched polyester film at 230 to 250 ° C. , a sixth step of heat-setting the heat-treated polyester film at 200 to 220 ° C.

In addition, a method for producing a hydrophilic polyester film according to another aspect of the present invention includes the first step of preparing a polyester sheet from a polyethylene terephthalate chip from which moisture is removed, and applying the above-described hydrophilic coating solution on the polyester sheet. The second step, the third step of preparing a uniaxially stretched polyester film by stretching the polyester sheet coated with the hydrophilic coating liquid 3 to 5 times in the machine direction (MD), and the uniaxially stretched polyester sheet coated with the hydrophilic coating liquid A fourth step of preparing a biaxially stretched polyester film by stretching the polyester film 3 to 5 times in the transverse direction (TD), and a fifth step of heat-treating the biaxially stretched polyester film at 230 to 250 ° C. , a sixth step of heat-setting the heat-treated polyester film at 200 to 220 ° C.

The hydrophilic polyester film according to the present invention described above can be variously applied to medical, architectural, and household goods, and specifically, medical diagnostic strips or face shields, face protectors, eyewear such as goggles or glasses, car window shields or windows , glass windows of buildings, polymer films used in greenhouses, mirrors in bathrooms, food packaging materials requiring transparency, etc., but can be used in fields requiring anti-fog treatment, but their uses are not limited.

Hereinafter, the configuration of the present invention and its effects will be described in more detail through Examples and Comparative Examples. However, these examples are for explaining the present invention in more detail, and the scope of the present invention is not limited to these examples.

[Example]

[Example 1]

Preparation of hydrophilic layer coating solution

While stirring 94.05 parts by weight of water, 0.1 parts by weight of surfactant (Dynol 607 manufactured by Evonik) and 1.5 parts by weight of organosiloxane (KBM-503 manufactured by Shin-Etsu) were added, the pH was adjusted to 3 using an aqueous nitric acid solution, and the mixture was stirred for about 1 hour. . To the solution, 1.2 parts by weight of epoxy polyol (EPICLON CR5L manufactured by Dainippon Ink), 3.0 parts by weight of silica (SF30 manufactured by Ace Nanochem), and 0.15 parts by weight of a polyamine-based crosslinking agent (EPOMIN SP-012 manufactured by Nippon Catalyst) were sequentially added. The pH of the solution was adjusted to 10 using aqueous ammonia and stirred for 30 minutes to prepare a hydrophilic layer coating solution.

Manufacture of hydrophilic polyester film

Polyethylene terephthalate chips from which moisture was removed were put into an extruder, melt-extruded, and rapidly cooled and solidified with a casting drum having a surface temperature of 20° C. to prepare a polyethylene terephthalate sheet having a thickness of 8000 μm. After stretching the prepared polyethylene terephthalate sheet 3 to 5 times in the machine direction (MD) at 80 ° C., it was cooled to room temperature to prepare a uniaxially stretched polyester film. Thereafter, the prepared hydrophilic coating solution is coated on one side of the polyester film uniaxially stretched by the gravure coating method using a gravure coater, and the temperature is raised sequentially in a tenter to preheat, dry, and stretch 3 to 5 times in the transverse direction (TD) Then, heat treatment was performed in a tenter at 230 to 250° C., and heat-set at 200 to 220° C. to prepare a biaxially stretched hydrophilic polyester film. At this time, the coating thickness of the hydrophilic layer formed with the hydrophilic layer coating solution after drying is 40 nm.

[Example 2]

A hydrophilic polyester film was prepared in the same manner as in Example 1, except that the overall production speed of the polyester film compared to Example 1 was slowed by 10% and the temperature in the tenter was increased by 10% to activate the reaction between the hydrophilic material and the film. did

[Example 3]

A hydrophilic polyester film was prepared in the same manner as in Example 1, except that 0.6 parts by weight of organosiloxane was used.

[Example 4]

A hydrophilic polyester film was prepared in the same manner as in Example 1, except that 4.5 parts by weight of organosiloxane was used.

[Example 5]

A hydrophilic polyester film was prepared in the same manner as in Example 1, except that 0.6 parts by weight of epoxy polyol was used.

[Example 6]

A hydrophilic polyester film was prepared in the same manner as in Example 1, except that 0.9 parts by weight of silica was used.

[Comparative example]

[Comparative Example 1]

A hydrophilic polyester film was prepared in the same manner as in Example 1, except that organosiloxane was not used.

[Comparative Example 2]

A hydrophilic polyester film was prepared in the same manner as in Example 1, except that 0.3 parts by weight of organosiloxane was used.

[Comparative Example 3]

A hydrophilic polyester film was prepared in the same manner as in Example 1, except that 5.5 parts by weight of organosiloxane was used.

[Comparative Example 4]

A hydrophilic polyester film was prepared in the same manner as in Example 1, except that epoxy polyol was not used.

[Comparative Example 5]

A hydrophilic polyester film was prepared in the same manner as in Example 1, except that 6 parts by weight of epoxy polyol was used.

[Comparative Example 6]

A hydrophilic polyester film was prepared in the same manner as in Example 1, except that silica was not used.

[Comparative Example 7]

A hydrophilic polyester film was prepared in the same manner as in Example 1, except that 15 parts by weight of silica was used.

[Comparative Example 8]

A hydrophilic polyester film was prepared in the same manner as in Example 1, except that the polyamine-based crosslinking agent was not used.

[Comparative Example 9]

A hydrophilic polyester film was prepared in the same manner as in Example 1, except that 0.45 parts by weight of the polyamine-based crosslinking agent was used.

[Comparative Example 10]

A polyester film was prepared in the same manner as in Example 1, except that the hydrophilic coating solution was not coated.

[Comparative Example 11]

While stirring 94.05 parts by weight of water, 0.1 part by weight of a surfactant (Dynol 607 manufactured by Evonik) and 1.5 parts by weight of an organosiloxane (KBM-503 manufactured by Shin-Etsu) were added, the pH was adjusted to 3 using an aqueous nitric acid solution, and the mixture was stirred for about 1 hour. . To the solution, 1.2 parts by weight of epoxy polyol (EPICLON CR5L manufactured by Dainippon Ink Co., Ltd.), 3.0 parts by weight of silica (SF30 manufactured by Ace Nanochem Co., Ltd.), and 0.15 parts by weight of a polyamine-based crosslinking agent (EPOMIN SP-012 manufactured by Nippon Catalyst) were sequentially added, followed by 30 A coating solution was prepared by stirring for a minute.

After that, a hydrophilic polyester film was prepared in the same manner as in Example 1.

[Comparative Example 12]

A hydrophilic polyester film was prepared in the same manner as in Comparative Example 11, except that organosiloxane was not used.

[Comparative Example 13]

A hydrophilic polyester film was prepared in the same manner as in Comparative Example 11, except that the polyamine-based crosslinking agent was not used.

[Comparative Example 14]

A hydrophilic polyester film was prepared in the same manner as in Comparative Example 11, except that silica was not used.

Physical properties were measured through the following experimental examples using the hydrophilic polyester films according to Examples 1 to 15 and Comparative Examples 1 to 5, and the results are shown in Table 1 below.

[Experimental example]

1. Measurement of water contact angle

Using a dynamic contact angle meter (KRUSS DSA100), 3 μl of water droplets were dropped on the polyester films prepared in Examples and Comparative Examples, and the contact angles of the water droplets measured within 10 seconds were measured 5 times per sample and averaged.

2. ATR-FTIR analysis

Samples of the polyester films prepared in Examples and Comparative Examples were measured using an FT-UV-VIS-IR Spectroscopic Imaging Microscope (Vertex 80) at 600-4000 cm ^-1 using an ATR and DLaTGS detector at 128scan, Resolution 4cm ^-1 , 3 spots per sample were measured. Among them, the ATR-FTIR spectrum of the hydrophilic polyester film according to Example 1 and Comparative Example 1 of the present invention is shown in FIG. In Figure 1, identification number "1" is the ATR-FTIR spectrum of the hydrophilic polyester film according to Comparative Example 1, "2" is the ATR-FTIR spectrum of the hydrophilic polyester film according to Example 1.

3. Durability evaluation 1

A water film is formed when the polyester film prepared in Examples and Comparative Examples is left on 3 cm of a hot water bath at 80 ° C with the coated surface facing the water surface. At this time, after exposure for 1 minute, wiping the water film layer formed on the surface with Kimwipes was repeated 5 or more times, and then the degree of change in the coating layer was measured by measuring the water contact angle.

4. Durability evaluation 2

The polyester films prepared in Examples and Comparative Examples were placed in an oven at 47° C. and allowed to stand for 30 days, and then the water contact angle was measured to observe changes.

sample I _1340cm-1 /I _1409cm-1 Water contact angle (°) durability 1
Water contact angle (°) durability 2
Water contact angle (°) Example 1 0.9 19 22 20 Example 2 0.6 19 21 22 Example 3 1.1 20 23 21 Example 4 0.6 21 23 21 Example 5 0.9 23 25 23 Example 6 0.7 21 24 22 Comparative Example 1 1.6 20 56 55 Comparative Example 2 1.3 20 33 29 Comparative Example 3 0.4 29 39 37 Comparative Example 4 1.0 45 52 50 Comparative Example 5 0.9 18 31 32 Comparative Example 6 0.7 32 34 35 Comparative Example 7 0.7 14 25 24 Comparative Example 8 0.8 17 46 45 Comparative Example 9 0.8 40 51 52 Comparative Example 10 1.6 65 66 65 Comparative Example 11 1.5 35 55 45 Comparative Example 12 1.6 34 66 65 Comparative Example 13 1.5 32 51 55 Comparative Example 14 1.5 40 58 56

As can be seen in Table 1 above, the hydrophilic polyester film having the components and contents according to an embodiment of the present invention has an ATR-FTIR spectrum ratio of I _1340cm-1 /I _1409cm-1 values greater than 0.5 and less than 1.3. It can be confirmed that it has excellent hydrophilicity by having a range of and excellent durability by having a change in water contact angle within 5 degrees under various conditions.

However, when organosiloxane is not used as in Comparative Example 1, sufficient chemical bonding is not generated, or when organosiloxane is used in excess as in Comparative Example 3, due to the hydrophobic nature of organosiloxane, the ratio of the ATR-FTIR spectrum, I _1340cm-1 /I _1409cm-1 values are all out of the range of more than 0.5 and less than 1.3, so the change in the water contact angle is large, so it can be seen that the durability is poor. In addition, when a small amount of organosiloxane is used as in Comparative Example 2, it can be seen that the ratio of the ATR-FTIR spectrum, I _{1340 cm-1} /I _{1409 cm-1,} has a similar value, but the durability is poor.

In addition, as in Comparative Examples 4 and 5, when epoxy polyol is not used or excessively used, it can be confirmed that neither hydrophilicity nor durability can be secured.

In addition, when silica is not used as in Comparative Example 6, hydrophilicity and durability can be secured to some extent, but hydrophilicity at the level targeted by the present invention is not obtained, and when silica is used in excess as in Comparative Example 7, durability is It can be seen that it is difficult to obtain.

In addition, it can be confirmed that durability cannot be secured when the polyvalent amine-based crosslinking agent is not used, as in Comparative Example 8, or hydrophilicity and durability are difficult to be secured when an excessive amount of the multivalent amine-based crosslinking agent is used, as in Comparative Example 9.

In addition, even if the hydrophilic coating solution according to the present invention is not applied as in Comparative Example 10 or the hydrophilic coating solution is used as in Comparative Examples 11 to 14, when the pH is not adjusted to 8-10 after hydrolysis of the coating solution, the polyester film and sufficient It can be seen that it is difficult to secure hydrophilicity and durability because chemical bonding is not achieved.

Although the above description has described a preferred embodiment of the present invention, the ratio of I _1340cm-1 /I _1409cm-1 of the hydrophilic polyester film according to an embodiment of the present invention is various compositions of materials used and their content ratio and It goes without saying that this can also be achieved according to film forming conditions and the like.

Although the preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concept of the present invention defined in the following claims are also made according to the present invention. falls within the scope of the rights of

1: ATR-FTIR spectrum of hydrophilic polyester film according to Comparative Example 1
2: ATR-FTIR spectrum of the hydrophilic polyester film according to Example 1

Claims (17)

Including a polyester film and a hydrophilic layer on at least one side thereof,
The hydrophilic layer has a water contact angle of 30 degrees or less,
The hydrophilic layer satisfies Equation 1 below,
(Equation 1)
0.50< I _{1340 cm-1} / _{I 1409 cm-1} <1.30
Here, I is the height of the absorbance peak at each wave number in the FTIR spectrum measured by the ATR method,
The hydrophilic layer is placed in an oven at 47 ° C. and left for 30 days, and then the change in water contact angle is within 5 degrees, a hydrophilic polyester film. According to claim 1,
The hydrophilic layer is coated with a hydrophilic coating solution comprising at least one organic hydrophilic material selected from epoxy polyol and polyethylene oxide, at least one inorganic hydrophilic material selected from silica, alumina and titanium oxide, an organic siloxane compound, a polyamine-based crosslinking agent, and a surfactant. , hydrophilic polyester film. According to claim 2,
The organic siloxane compound is a siloxane compound having at least one reactive group among an epoxy group, an amino group, and an ethylene group, a hydrophilic polyester film. According to claim 2,
The organosiloxane compound is 3-glycidoxypropylaminotrimethoxysilane, 3-glycidoxypropylaminotriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-( Meta) acryloyltrimethoxysilane or 3-(meth)acryloyltriethoxysilane, a hydrophilic polyester film. According to claim 2,
0.5 to 5 parts by weight of the organic hydrophilic material, 0.5 to 10 parts by weight of the inorganic hydrophilic material, 0.5 to 5 parts by weight of the organosiloxane compound, and 0.15 to 1.0 parts by weight of the surfactant per 100 parts by weight of the hydrophilic coating solution. polyester film. According to claim 2,
The polyvalent amine-based crosslinking agent comprising 10 to 30 parts by weight per 100 parts by weight of the organic hydrophilic material, a hydrophilic polyester film. According to claim 2,
The surfactant is an ionic surfactant or a nonionic surfactant, a hydrophilic polyester film. According to claim 2,
The thickness of the hydrophilic layer is 10nm to 200nm, a hydrophilic polyester film. According to claim 1,
A hydrophilic polyester film having at least one chemical bond of a silicone ether bond, an amide bond, and an ether bond between the hydrophilic layer and the polyester film. According to claim 1,
The hydrophilic layer is a hydrophilic polyester film in which the change in the water contact angle is within 5 degrees after wiping the water film layer generated on the surface at least 5 times when exposed to a hot water bath at 80 ° C. for 1 minute. delete In the method for producing a hydrophilic polyester film according to claim 1,
A first step of manufacturing a polyester sheet from polyethylene terephthalate chips from which moisture has been removed;
A second step of preparing a uniaxially stretched polyester film by stretching the polyester sheet 3 to 5 times in a machine direction (MD);
A third step of applying a hydrophilic coating solution on the uniaxially stretched polyester film;
A fourth step of preparing a biaxially stretched polyester film by stretching the uniaxially stretched polyester film coated with the hydrophilic coating liquid 3 to 5 times in the transverse direction (TD);
A fifth step of heat-treating the biaxially stretched polyester film at 230 to 250 ° C;
A method for producing a hydrophilic polyester film comprising a sixth step of heat-setting the heat-treated polyester film at 200 to 220 ° C. In the method for producing a hydrophilic polyester film according to claim 1,
A first step of manufacturing a polyester sheet from polyethylene terephthalate chips from which moisture has been removed;
A second step of applying a hydrophilic coating solution on the polyester sheet;
A third step of preparing a uniaxially stretched polyester film by stretching the polyester sheet coated with the hydrophilic coating solution 3 to 5 times in a machine direction (MD);
A fourth step of preparing a biaxially stretched polyester film by stretching the uniaxially stretched polyester film coated with the hydrophilic coating liquid 3 to 5 times in the transverse direction (TD);
A fifth step of heat-treating the biaxially stretched polyester film at 230 to 250 ° C;
A method for producing a hydrophilic polyester film comprising a sixth step of heat-setting the heat-treated polyester film at 200 to 220 ° C. According to claim 12 or 13,
The hydrophilic coating solution is a method for producing a hydrophilic polyester film, which is a mixture of a surfactant, an organosiloxane, an organic hydrophilic material, an inorganic hydrophilic material, and a polyvalent amine-based crosslinking agent in order. According to claim 12 or 13,
The hydrophilic coating solution is hydrolyzed at pH 2-5 by adding a surfactant and organosiloxane, and then the pH is adjusted to 8-10 by adding an organic hydrophilic material, an inorganic hydrophilic material, and a digamine-based crosslinking agent. Manufacturing method of polyester film. According to claim 14,
The organic hydrophilic material is at least one of epoxy polyol and polyethylene oxide, a method for producing a hydrophilic polyester film. According to claim 14,
The inorganic hydrophilic material is at least one of silica, alumina and titanium oxide, a method for producing a hydrophilic polyester film.

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