WO2016056831A1 - Ink composition for bleaching polarizing film for inkjet printer, and method for preparing polarizing film comprising bleached pattern formed thereon - Google Patents

Abstract

The present invention relates to: an ink composition for bleaching a polarizing film for an inkjet printer, comprising a strong base, a volatilization inhibitor, a viscosity enhancer and a solvent, wherein the strong base amount is 5-30 wt% on the basis of the total composition; and a method for preparing a polarizing film having improved pattern transparency, by using the same.

Description

Polarizing Film Bleaching Ink Composition for Inkjet Printer and Manufacturing Method of Polarizing Film with Bleaching Pattern

This application is filed with the Korean Patent Application No. 10-2014-0134846 filed October 07, 2014, the Korean Patent Application No. 10-2014-0146318 filed October 27, 2014, and the Korean Patent Application No. 10-2015 filed September 25, 2015 Claiming the benefit of priority based on -0136882, all the contents disclosed in the literature of that Korean patent application are incorporated as part of this specification.

The present invention relates to a polarizing film bleaching ink composition for an inkjet printer and a method for producing a polarizing film having a bleaching pattern.

With the recent remarkable development of the IT industry, the LCD (liquid crystal display) industry, which is one of the key components of the IT industry, is also a medium for delivering various information as the modern industrial society develops into a highly informationized era. It is developing.

In general, a flat panel display device such as an LCD or an organic EL may attach a polarizing film to a surface of a substrate so that external light may be reflected to a surface on which an image is realized so that a user may recognize the screen correctly.

 The polarizing film adheres to both surfaces of a flat panel display liquid crystal cell such as an LCD or an organic EL and functions as part of a liquid crystal display panel. The liquid crystal display panel has a configuration in which a polarizing film is bonded to both surfaces of a liquid crystal cell. Specifically, the polarizing film includes a polarizing plate in the center and protective films attached to both surfaces of the polarizing plate through an adhesive layer. The protective films are disposed on the upper and lower sides of the polarizing plate to prevent damage to the polarizing plate. The upper protective film (separated film) is peeled off and discarded before being attached to the liquid crystal cell, whereby the exposed adhesive layer mediates the bonding between the polarizing plate and the liquid crystal cell. When the lower protective film (protect film) is also attached to the liquid crystal cell, it is peeled off and discarded. At this time, the pressure-sensitive adhesive layer is also peeled off together with the protective film. The protective films may be formed of an ester resin such as PET.

The polarizing film may be a polyvinyl alcohol (PVA), such as iodine or dichroic dye is adsorbed.

Since the polyvinyl alcohol film has excellent optical performance such as transparency and polarization among general polymer films, and at the same time, mechanical properties such as elastic modulus, tensile strength, and tensile elongation are very excellent, and thus, the polyvinyl alcohol film has gained great attention as an optical material such as a polarizing film. In the past, polarizing films were mainly used for watches, electronic calculators, automobile dashboards, small liquid crystal televisions, and small LCD laptops. However, as large notebooks and large color televisions have recently been developed, they can be used in large areas. Development is required.

On the other hand, since the polarizing film used for the display is very low transparency, when attaching to the inside and the outside of the cover glass, it is necessary to make certain parts such as the camera or sensor part of the display transparent.

Thus, in order to solve such a problem, a method of transmitting optical energy to a local part by laser to excite and decompose iodine molecules included in a polarizing element of a polarizing film to lose optical properties has been devised. However, in this method, the humidity and heat tests are performed in preparation for humidity and heat that may occur during the process, and there is a problem that the original state is restored when the humidity and heat tests are finished.

As another method, a method of optically transparent a polarizing film using an oxidation / reduction reaction of sodium thiosulfate (Na ₂ S ₂ O ₃ ) and iodine ion (I ⁻ ) has been devised. However, this method also lacks the transparency of the polarizing element of the bleached polarizing film, there is a problem that is restored to its original state after a short time left at room temperature.

In addition, existing large or small display is made of tempered glass when broken, there is a problem that the glass is scattered, if there is no protective film separately.

In the method of improving the transparency of the polarizing film of the prior art, there is a problem that the polarization of the polarizing element of the polarizing film is insufficient, and is restored to its original state in a short time.

Accordingly, an object of the present invention is to provide an ink composition for an ink jet printer for bleaching of a polarizing film. That is, an object of the present invention is to bleach the polarizing film using an inkjet printing process.

In particular, it aims at making the polarizing element of a polarizing film transparent locally or over the whole using the ink composition of this invention.

In addition, the transparency is maintained even after the moisture resistance and / and heat resistance test, and furthermore, the ink composition is smoothly discharged in the inkjet printer process, to form an accurate pattern on the polarizing film and to bleach.

In order to achieve the above object, the present invention provides a polarizing film bleaching ink composition for an inkjet printer comprising a strong base, a volatile inhibitor, a viscosity enhancer and a solvent, wherein the strong base is contained in 5 to 30% by weight based on the whole composition. .

According to a preferred embodiment of the present invention, the composition may further include any one or more selected from a defoaming agent and a surfactant, the composition may be for polarizing film bleaching. In addition, according to a preferred embodiment of the present invention, the polarizing film may be a PVA polarizing film.

Another aspect of the present invention (1) heating the polarizing film; (2) bleaching the ink composition by ejecting the ink composition through the inkjet head of the inkjet printer to the heated polarizing film; And (3) neutralizing the bleached polarizing film, wherein the discharge amount of the ink composition of step (2) is a bleaching pattern of 0.02 to 0.5 ml / cm ² per unit area of the heated polarizing film. It provides a formed polarizing film manufacturing method.

According to a preferred embodiment of the present invention, step (1) may be carried out at a temperature of 30 ~ 100 ℃, the ink composition may include a strong base, a volatile inhibitor, a viscosity enhancer and a solvent. In addition, according to a preferred embodiment of the present invention, the bleaching reaction of step (2) may be performed for 3 to 30 seconds. In addition, a preferred embodiment of the present invention step (3) may be performed by a method of immersing in a neutralizing solution or a method of applying a neutralizing solution. And after the step (3) (4) may further comprise the step of drying.

Another aspect of the present invention provides a polarizing film having a bleaching pattern formed by the production method of the present invention, and also provides a display including the polarizing film.

The ink composition of the present invention can be applied to an inkjet printing technique to bleach the polarizing elements of the polarizing film. That is, the ink composition of the present invention can chemically react the polarizing element of the polarizing film to make the optically transparent state.

Therefore, the ink composition of the present invention can be applied to the inkjet printing technology to pattern the specific parts such as the sensor, the camera portion to increase the transparency only, the polarizing film manufactured by the manufacturing method of the present invention specific parts such as the sensor, the camera portion Can be used where transparency is required.

In addition, the ink composition of the present invention has a very short bleaching time and can prevent volatilization and nozzle wetting. Because of this, the jetting and jetting stability is very excellent and the bleached pattern can be maintained even after the bleaching and moisture / heat test.

And in the present invention can provide an amount of the ink composition suitable for bleaching per unit area of the polarizing film.

The polarizing film to which the ink composition of the present invention is applied may prevent scattering of glass without a separate protective film layer when the cover glass is damaged.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail. The following detailed description is for the description of one embodiment of the present invention, although not limited to the scope of the claims defined by the claims.

When the polarizing element of the polarizing film is bleached according to the prior art, there is a problem that the transparency of the polarizing element is insufficient and is restored to its original state after being left at room temperature for a short time.

Therefore, the present inventors have made diligent efforts to improve the transparency of the polarizing film, and found that when bleaching the polarizing film using an inkjet process, the transparency of a specific pattern portion can be improved.

In addition, the present inventors have developed an ink composition that can be applied to an inkjet process in order to improve the transparency of a specific pattern of the polarizing film. And when the pattern to a specific portion of the polarizing film with the ink composition, only bleaching the portion, it was confirmed that the transparency is significantly improved to complete the present invention.

That is, the present invention includes a strong base, a volatile inhibitor, a viscosity enhancer and a solvent,

It provides a polarizing film bleaching ink composition for an inkjet printer wherein the strong base is contained in 5 to 30% by weight based on the whole composition.

And according to a preferred embodiment of the present invention, the polarizing film may be a PVA polarizing film.

First, in the present invention, a polarizing film (Polarizing Film) generally refers to a film having a function of converting natural light into polarized light, this polarizing function is implemented by a material that is dyed to the polarizing plate. In general, an iodine type polarizing film in which iodine is salted is used as a polarizing material in a liquid crystal display. The iodine type polarizing film is produced by dyeing a polyvinyl alcohol (PVA) film using dichroic iodine or a dichroic dye, orientating it in a predetermined direction by a method such as uniaxial stretching, and used in LCDs and the like. For example, the unstretched PVA film is uniaxially stretched in an aqueous solution and then immersed in a solution containing iodine and potassium iodide, or the unstretched PVA film is immersed in a solution containing iodine and potassium iodide and then uniaxially stretched. Alternatively, the non-stretched PVA film is uniaxially stretched in a solution containing iodine and potassium iodide, or the unstretched PVA film is uniaxially stretched in a dry state and then immersed in a solution containing iodine and potassium iodide to prepare a polarizing film. .

Bleaching (bleaching) in the present invention means chemical reaction to the polarizing element of the polarizing film to make a part or the entire surface in the optically transparent state.

Hereinafter, each component which comprises the ink composition for inkjet printers of this invention is demonstrated.

First, the strong base will be described.

The strong base included in the composition of the present invention serves to make the polarizing element of the polarizing film transparent and to adjust the acidity of the ink composition. As for the ink composition of this invention, 13-14 pH is preferable.

According to a preferred embodiment of the present invention, the strong base is any one or more selected from potassium hydroxide (KOH), sodium hydroxide (NaOH), calcium hydroxide (Ca (OH) ₂ ) and barium hydroxide (Ba (OH) ₂ ) It may include, and most preferably may be potassium hydroxide.

And the strong base relative to the total weight percentage of the total ink composition may include 5 to 30% by weight, preferably 10 to 15% by weight.

If the strong base is less than 5% by weight, the concentration may be low, so that the bleaching speed may be insufficient. If the amount is more than 30% by weight, the head of the inkjet printer may be damaged.

Next, the volatilization inhibitor will be described.

In the present invention, the volatilization inhibitor serves to suppress the nozzle clogging due to volatilization of the ink composition.

According to a preferred embodiment of the present invention, the volatilization inhibitor 2-pyrrolidone (2-Pyrrolidone), glycerin (Glycerine), 2-methyl-1,3-propanediol (2-Methyl-1,3-propanediol ) And propylene glycol (Propylene Glycol) may include any one or more, preferably propylene glycol (Propylene Glycol).

The volatilization inhibitor may include 1 to 50 wt% with respect to the total weight percentage of the total ink composition, and preferably 10 to 20 wt%.

If it is less than 1% by weight, the ink may volatilize to cause nozzle clogging, and if it exceeds 50% by weight, the bleaching speed may be slowed, so the above range is preferable.

Next, the viscosity enhancer will be described.

The viscosity enhancer in the present invention serves to help form the ink droplets at a constant size when jetting at room temperature, for example, 25 ℃. In addition, the viscosity of the ink composition of the present invention is jettable viscosity, preferably 3 to 20 cP, more preferably 4 to 15 cP.

According to a preferred embodiment of the present invention, the viscosity enhancer may include any one or more selected from glycerin, polyvinylpyrrolidone and 2-hydroxyethyl cellulose. And preferably 2-hydroxyethyl cellulose.

And the viscosity enhancer with respect to the total weight percentage of the total ink composition may comprise 0.1 to 5% by weight, preferably 1 to 3% by weight.

If the viscosity enhancer is less than 0.1% by weight, the viscosity is lowered, so that the drop formation of the ink composition is not constant. If the viscosity is higher than 5% by weight, the viscosity is increased, not only the jetting is poor, but the bleaching speed is delayed. .

However, glycerin can be used both as a volatile inhibitor and a viscosity enhancer. In the present invention, the volatile inhibitor and the viscosity enhancer cannot use glycerin at the same time.

The following solvent is described.

The solvent of the present invention serves to maintain the total amount of the ink composition at 100% by weight, and means the remaining amount other than the composition.

The solvent may be any conventional one, but may preferably be water. And when using water as said solvent, it is preferable to use the deionized water or / and distilled water whose specific resistance value is 18 MPa * cm or more as water for a continuous process.

An ink composition for an inkjet printer of the present invention is a specific embodiment,

Potassium hydroxide may be used as the strong base, and may further include an antifoaming agent and a surfactant together with a volatile inhibitor, a viscosity enhancer, and a solvent.

According to a preferred embodiment of the present invention, the ink composition of the present invention may further include any one or more selected from an antifoaming agent and a surfactant.

The said defoaming agent is demonstrated.

The ink composition of the present invention may generate bubbles when the ink is added by adding a surfactant. This may not remove bubbles even after being put into the print head storage unit, and may cause a problem that the nozzle is clogged when jetting. Therefore, by including the said antifoaming agent in an ink composition, foaming can be suppressed.

According to a preferred embodiment of the present invention, the antifoaming agent may be used as usual. Preferably, it may include any one or more selected from trade names Surfynol 104A, Surfynol 104BC, Surfynol 104DPM, Surfynol 104E, Surfynol 104H, Surfynol 104NP, Surfynol 104PA, Surfynol 104PG-50, and Surfynol 104S. And preferably Surfynol 104E. The antifoaming agent may include 0.01 to 5 wt%, and preferably 0.1 to 1 wt% based on the total weight percentage of the total ink composition.

If the antifoaming agent is less than 0.01% by weight, there is a problem that the ink composition is foamed to cause nozzle clogging due to the bubble is not removed even after the ink composition is added to the inkjet head storage. And when the antifoaming agent exceeds 5% by weight, there is a problem that the surface tension is excessively reduced, causing the nozzle wetting phenomenon, the above range is preferable.

Next, the surfactant will be described.

In the present invention, by further including the surfactant in the ink composition, it is possible to lower the surface tension to facilitate ink jetting, and to properly spread on the substrate after jetting.

According to one preferred embodiment of the present invention, the surfactant may be used as usual. Preferably may include any one or more selected from the trade name Surfynol 420, Surfynol 440, Surfynol 485 and Surfynol 485W, preferably Surfynol 485 and / or Surfynol 485w. And based on the total weight percentage of the total ink composition, the surfactant may include 0.1 to 5% by weight, preferably 0.25 to 1% by weight.

If the surfactant is less than 0.1% by weight, the surface tension of the ink is not high, jetting is not good, and after the jetting does not spread well on the substrate does not form a pattern. In addition, when the surfactant exceeds 5% by weight, the surface tension of the ink is too low, so that the wetting phenomenon occurs in the print head nozzle portion, and the ink is excessively spread even after jetting to the substrate, making pattern formation difficult. Therefore, it is preferable to further include surfactant in the ink composition of this invention in the said range.

In addition to the above-mentioned components, the ink composition for an inkjet printer of the present invention may further include any one or more selected from metal ion sequestrants, corrosion inhibitors, and pH adjusters.

In conclusion, the present invention provides an ink composition for an inkjet printer, and by using the same, transparency of the polarizing film may be improved.

The ink composition of the present invention contains a strong base in a preferred content in order to secure optical transparency in accordance with the pattern that needs to improve the transparency in the polarizing film. And the content of the volatilization inhibitor of the present invention can suppress the clogging phenomenon of the nozzle portion due to the bleaching time control and ink drying. In addition to this, by adjusting the jetting performance according to the content of the viscosity enhancer can be used by appropriately applied to the polarizing film.

The present invention also provides a method for producing a polarizing film having a bleaching pattern using the ink composition for an inkjet printer provided by the present invention.

Specifically, the present invention (1) heating the polarizing film; (2) bleaching the ink composition by ejecting the ink composition through the inkjet head of the inkjet printer to the heated polarizing film; And (3) neutralizing the bleached polarizing film, wherein the discharge amount of the ink composition of step (2) is a bleaching pattern of 0.02 to 0.5 ml / cm ² per unit area of the heated polarizing film. It provides a formed polarizing film manufacturing method.

First, the step (1) of heating the polarizing film will be described.

The bleaching of the present invention is a chemical reaction and requires thermal energy during the reaction. Therefore, the step of heating the polarizing film should be performed first, the heating temperature may be 30 ~ 100 ℃, preferably 40 ~ 70 ℃.

When the heating temperature is less than 30 ℃, the speed of the chemical reaction is slowed and the bleaching time is long, and when the temperature is 100 ℃ or more, the deformation of the polarizing film may occur, and because the ink is evaporated too fast, it is difficult to form a pattern. Range is preferred. In addition, the heating step of the present step may be further suitably further performed before, simultaneously with, and after jetting.

Next, (2) the step of bleaching reaction by discharging the ink composition through the inkjet head of the inkjet printer to the heated polarizing film.

In this step, the ink composition may be discharged or jetted using a bleaching ink through an inkjet head of the inkjet printer, and then bleached.

At the time of discharging, the dot pitch of the droplets must be adjusted to optimize the amount of bleaching ink per unit area of the polarizing film. This prevents a portion in which a droplet does not fall in a desired pattern so that no bleaching is performed, and at the same time, too many droplets may be dropped to prevent deformation and distortion of the polarizing film.

In the present invention, the discharge amount of the ink composition per unit area of the heated polarizing film is preferably 0.02 to 0.5 ml / cm ² , preferably 0.03 to 0.1 ml / cm ² . It is necessary to maintain the above range when forming a line or surface shape that is a pattern does not occur empty space can be adjusted according to the process efficiency. That is, the printing speed and the ink application amount can be appropriately adjusted according to the process speed. For example, in the case of a printer, the process speed may be controlled by adjusting the frequency of jetting. In addition, when the polarizing film is thick, it is possible to apply a larger amount of ink.

And the droplet spacing of the ink composition thus formed is generally 5 ~ 508um, preferably 20 ~ 200um. The spacing between the droplets means the distance from the center of the droplet to the center of another droplet. Therefore, according to one embodiment of the present invention, when the droplet size of the ink composition is about 140um in the inkjet printing process of the present invention, the distance from the center of the droplet to the center of another droplet should be 140um or less. Can be achieved. The droplet spacing may be displayed as an average of the Y-axis spacing and the X-axis spacing by fixing the Y-axis and adjusting the droplet spacing of the X-axis according to the discharge amount.

In the pattern printing for forming the pattern, when the ink is discharged downward from the inkjet head, the inkjet head should be spaced apart from the upper part of the polarizing film. In this case, the inkjet head and the polarizing film may be moved while left, right, front and back without contact, and the polarizing film may be left, right, front and rear under the inkjet head while the head is fixed. It is also possible to move in the direction.

In addition, it is also possible to form a pattern while installing the head so that ink is discharged in the lateral direction and changing the relative positions of the head and the polarizing film to up, down, left and right.

The interval between the inkjet head and the polarizing film may be 1 to 10,000 um, and preferably 500 to 3,000 um.

According to one preferred embodiment of the present invention, the reaction for forming the bleaching pattern may be carried out at a temperature of 30 ~ 100 ℃, preferably 40 ~ 70 ℃. And the reaction time for forming the bleaching pattern may be performed for a time of 3 to 30 seconds. The reaction time for forming the bleaching pattern is defined from (1) step of heating the polarizing film to 30 ~ 100 ℃, from the moment the ink is dropped to the heated polarizing film to the moment the polarizing film becomes transparent.

At this time, if the temperature is low or the time is short, the bleaching does not occur completely, if the time is long there is a problem that takes a long process speed.

Next, the neutralization step will be described.

The polarizing film bleached in step (2) has to be neutralized with water or a slightly acidic solution because the ink composition is strongly alkaline at 13-14 pH. And the temperature of the neutralizing step may be preferably 25 ~ 70 ℃.

The neutralization step may be performed by immersing the polarizing film printed with bleaching ink in the neutralizing solution or by applying the neutralizing solution to the polarizing film printed with the bleaching ink. And according to a preferred embodiment of the present invention, the neutralization solution may be water or weakly acidic solution. The weakly acidic solution may be a solution having a pH in the range of 5 to 6, including any one or more selected from boric acid, nitric acid, and acetic acid.

In addition, the coating method may be selected from the group consisting of spraying, steam, curtain coating, inkjet coating, screen printing, bar coating and slit die coating and dip coating onto a film on which a bleaching ink is printed. It is also possible to apply by any one of the methods or other methods.

And according to a preferred embodiment of the present invention, after the neutralization step of the step (3) may further comprise the step of drying (4).

After the step (3), the drying is performed through an oven or air blowing to remove the moisture and impurities remaining in the polarizing film in the neutralization process. At this time, it is preferable to apply tension to the polarizing film so that wrinkles do not occur in the polarizing film. The drying method is not particularly limited, and may be an oven or infrared or dry air or hot air method that is commonly used by the person, and two or more methods may be applied sequentially or simultaneously.

On the other hand, the present invention provides a polarizing film having a bleaching pattern formed by the manufacturing method of the present invention, and also provides a display including the polarizing film.

In conclusion, the present invention can improve the transparency of the polarizing film by a manufacturing method of forming a bleaching pattern on the polarizing film using an ink composition for an inkjet printer.

In addition, the present invention provides an appropriate amount of ejection of the ink composition in order to secure optical transparency to the pattern that needs to improve the transparency in the polarizing film. Then, the bleaching reaction is controlled by temperature and time, and a configuration of the ink composition may be appropriately combined to prepare a polarizing film having a bleaching pattern suitable for a situation.

Hereinafter, the present invention will be described in more detail with reference to Examples, but embodiments of the present invention disclosed below are exemplified to the last, and the scope of the present invention is not limited to these embodiments. The scope of the invention is indicated in the appended claims, and moreover contains all modifications within the meaning and range equivalent to the claims. In addition, "%" and "part" which show content in a following example and a comparative example are a basis of weight unless there is particular notice.

1. Examples 1 to 8 and Comparative Examples 1 to 5

The ink composition was prepared by mixing according to the ingredients and contents shown in Table 1 above.

Table 1

weight%	Potassium hydroxide	Volatilization inhibitor		Viscosity enhancers		Surfactants		Antifoam		Secondary distilled water
Example 1	10	Propylene glycol	10	2-Hydroxyethyl cellulose	One	Surfynol485	One	Surfynol104E	0.1	77.9
Example 2	10		20		One		One		0.1	67.9
Example 3	10		20		1.5		One		0.1	67.4
Example 4	10		20		2		One		0.1	66.9
Example 5	10	2-Pyrrolidone	10	2-Hydroxyethyl cellulose	One	Surfynol485	One	Surfynol104E	0.1	77.9
Example 6	10	Glycerin	10		One		One		0.1	77.9
Example 7	10	2-Methyl-1, 3-propanediol	10		One		One		0.1	77.9
Example 8	10	PropyleneGlycol	20	Polyvinylpyrrolidone	One		One		0.1	67.9
Comparative Example 1	10	X		X	X	X		X		90
Comparative Example 2	10	X		Glycerin	55	X		X		35
Comparative Example 3	10	PropyleneGlycol	10	PEG (Mn = 3400) (not green)	2	X		X		78
Comparative Example 4	2	PropyleneGlycol	10	2-Hydroxyethyl cellulose	One	Surfynol485	One	Surfynol104E	0.1	85.9
Comparative Example 5	35	PropyleneGlycol	10	2-Hydroxyethyl cellulose	One	Surfynol485	One	Surfynol104E	0.1	52.9

2. Experimental Examples 1-4

Examples 1 to 8 and Comparative Examples 1 to 5 were evaluated as shown in Table 2 below.

1) Bleaching Time Measurement

The bleaching time defines the bleaching time from the moment when the ink composition falls on the polarizing film to the moment when the polarizing film becomes transparent.

1) The prepared PVA polarizing film was heated to 60 degreeC by the method which can be measured irrespective of whether ink can be jetted. Then, the ink compositions prepared in Comparative Examples 1 to 5 were dropped one drop onto the heated film using the dropper, and the time taken until the polarizing film of the portion where the droplets were formed became transparent.

2) The PVA polarizing film prepared by the method made into the ink which can be jetted was heated to 60 degreeC. Then, the ink composition prepared in Examples 1 to 8 was discharged to the inkjet head to print a surface on which the ink droplets were set at a distance defined by the horizontal and vertical spacing on the heated film. And the time taken from immediately after printing to the moment the polarizing film becomes transparent was measured. However, the horizontal and vertical spacing of the droplets to be set do not have to be the same, and the printed surfaces are each 0.2 cm or more in width and length.

2) viscosity measurement

It was measured based on room temperature (25 ℃) using a BROOKFIELD DV-III ULTRA instrument.

3) Phase separation confirmation

Phase separation was visually confirmed for storage stability evaluation.

4) Check jetting

The jetting persistence was confirmed by continuously jetting the ink composition over the initial printed state and at least 3 minutes and then comparing the print state. When jetting the ink composition, the size and spacing of each drop were checked by optical microscope to evaluate the jetting performance.

TABLE 2

	Bleaching Time (sec)	Viscosity	Phase separation	Jetting	Head damage
Example 1	13	4.01	none	○	X
Example 2	13	6.8	none	○	X
Example 3	13.5	7.7	none	○	X
Example 4	14	10.3	none	○	X
Example 5	15	4.73	none	○	X
Example 6	19	7.41	none	○	X
Example 7	15	5.40	none	○	X
Example 8	14	2.80	none	△	X
Comparative Example 1	10	1.03	none	X	X
Comparative Example 2	-	13.3	none	-	X
Comparative Example 3	-	-	Polymer not melted	-	X
Comparative Example 4	30	3.8	none	○	X
Comparative Example 5	13	6.2	none	○	○

Referring to Table 2, it can be seen that Examples 1 to 8 are superior to Comparative Examples 1 to 5.

The above examples and comparative examples prepared the ink composition including 10 wt% of 13 to 14 pH KOH to enable bleaching in 20 seconds.

And to maintain the viscosity at 4 ~ 15 cP at room temperature (25 ℃) to prepare an ink using a polyvinylpyrrolidone (Polyvinylpyrrolidone), glycerin (Glycerine) and 2-hydroxyethyl cellulose (2-Hydroxyethyl cellulose) as a viscosity enhancer It was.

In Examples 1 to 4, propylene glycol (Propylene Glycol) was used as the volatile inhibitor, and Example 1 included 10 wt%, and the bleaching time was excellent as 13 seconds. In addition, Examples 2 to 4 included an increase in the volatilization inhibitor to 20% by weight in order to suppress volatilization as much as possible, while the bleaching time was the same as 13 seconds.

In addition, Examples 1 to 4 containing propylene glycol (Propylene Glycol) as a result of evaluating the jetting persistence was very excellent jetting stability.

In Example 5, a volatile inhibitor, a viscosity enhancer, and a surfactant were introduced, and the bleaching time was delayed by 15 seconds or more than that of Comparative Example 1 including 10 wt% of 2-pyrrolidone as a volatile inhibitor. . In Example 6 using glycerin (Glycerine) as a volatile inhibitor instead of 2-pyrrolidone at the same weight percentage as in Example 5, the viscosity is good at 7.41 cP (25 ° C.).

Example 7 used 2-methyl-1,3-propanediol as a volatile inhibitor. There was no phase separation and jetting was possible.

In Comparative Example 1, the bleaching time was very short as 10 seconds, but the viscosity was low at 1.03 cP at room temperature (25 ° C.) and the surface tension was high, so that jetting was difficult. In addition, it can be seen that the ink is easily evaporated, the nozzle is clogged, and the drop of ink is not uniform when jetting, which is not suitable for the inkjet ink.

In the case of Comparative Example 2 using glycerin as a viscosity enhancer, the viscosity enhancing effect was low, so the jetting stability was insufficient, and 2-hydroxyethyl cellulose had the highest bleaching rate compared to the viscosity increase. Able to know.

In the case of Comparative Example 4 having a low content of strong bases, there was a problem that the bleaching time took 30 seconds or more, thereby significantly delaying the bleaching speed. Also, in Comparative Example 5, in which the content of strong bases was too high, the head of the inkjet printer It can be seen that there is a problem that the phenomenon is damaged, it is possible to maintain the optimum bleaching speed in the strong base content range of the present invention.

1. Examples 9-18 and Comparative Examples 6-7

Production Example

100% by weight of ink composition by mixing 10% by weight of calcium hydroxide, 20% by weight of propylene glycol, 1% by weight of 2-Hydroxyethyl cellulose, 1% by weight of surfactant (Surfynol485), 0.1% by weight of antifoaming agent (Surfynol104E) and 67.9% by weight of secondary distilled water Was prepared.

Examples 9-14

The prepared PVA polarizing film was heated to the temperature of Table 3 below. Next, 1 drop of the ink composition manufactured by the manufacture example was dropped on the heated PVA polarizing film using the dropper. And the time it takes for the polarizing film of the part in which the droplet was formed from the moment the ink composition fell was measured, and the result was shown in Table 3. However, the horizontal and vertical spacing of the droplets to be set do not have to be the same, and the printed surfaces are each 0.2 cm or more in width and length.

TABLE 3

	Example 9	Example 10	Example 11	Example 12	Example 13	Example 14
Substrate heating temperature (℃)	40	50	60	25	30	35
Bleaching Time (sec)	14	12.5	12.5	50	27	25

Examples 15-18 and Comparative Examples 6-7

The prepared PVA polarizing film was heated to 60 degreeC. And the ink composition manufactured by the manufacturing example was discharged to the inkjet printing process by the numerical value of Table 4 below on the heated PVA polarizing film as bleaching ink. The discharge amount per unit area was calculated by multiplying the volume and number of single droplets. The jet of the inkjet head and the polarizing film was jetted at 1,000 μm for the precise application of the ink, and the dot pitch of the ink composition was 40 μm on average.

Experimental Example

After printing, the bleaching pattern state due to the presence or absence of empty space, overflow phenomenon, and insufficient ink was evaluated using an optical microscope to evaluate the jetting performance.

-Bleaching

O: All patterned areas are transparent

△: partially transparent patterned area

X: The patterned area is not transparent

-Pattern sharpness

O: The bleaching pattern boundary is clear.

(Triangle | delta): A part of bleaching pattern boundary part is clear

X: Bleaching pattern border is not clear

Table 4

	Example 15	Example 16	Example 17	Example 18	Comparative Example 6	Comparative Example 7
Discharge amount per unit area (ml / cm 2 )	0.032	0.088	0.021	0.016	0.01	0.6
Bleaching	○	○	△	△	X	○
Pattern sharpness	○	○	△	△	X	X

Referring to Table 4, when looking at Comparative Example 6, if the discharge amount per unit area (cm ² ) is less than 0.02ml bleaching does not occur due to the thickness of the polarizing film. When the discharge amount exceeds 0.5 ml as in Comparative Example 7, the amount of ink is too large to obtain a desired pattern due to overflow.

On the other hand, in Examples 15 and 16, it can be seen that the discharge amount per unit area is 0.032 ml and 0.088 ml, respectively, so that bleaching is possible and the pattern sharpness is also excellent. In conclusion, it can be seen that the ink composition of the present invention is a composition suitable for an inkjet printer in order to improve the pattern transparency of the polarizing film.

Claims (27)

1. Containing a strong base, a volatile inhibitor, a viscosity enhancer and a solvent,

   A polarizing film bleaching ink composition for an inkjet printer, wherein the strong base is contained in an amount of 5 to 30 wt% based on the total composition.
2. The method according to claim 1,

   The strong base is polarized for inkjet printers, characterized in that any one or more selected from potassium hydroxide (KOH), sodium hydroxide (NaOH), calcium hydroxide (Ca (OH) ₂ and barium hydroxide (Ba (OH) ₂ )) Film Bleaching Ink Composition.
3. The method according to claim 1,

   The volatilization inhibitor is selected from 2-pyrrolidone, glycerin, 2-methyl-1,3-propanediol, and propylene glycol. Polarizing film bleaching ink composition for an inkjet printer, characterized in that it comprises any one or more.
4. The method according to claim 1,

   The viscosity enhancer bleaching polarizing film for an inkjet printer, characterized in that it comprises any one or more selected from glycerin, polyvinylpyrrolidone, and 2-hydroxyethyl cellulose. Ink composition.
5. The method according to claim 1,

   Polarizing film bleaching ink composition for an ink jet printer, characterized in that 1 to 50% by weight based on the total weight percentage of the total composition.
6. The method according to claim 1,

   Polarizing film bleaching ink composition for an inkjet printer, characterized in that the viscosity increasing agent relative to the total weight percentage of the total composition comprises 0.1 to 5% by weight.
7. The method according to claim 1,

   Polarizing film bleaching ink composition for an inkjet printer, characterized in that the composition further comprises any one or more selected from a defoaming agent and a surfactant.
8. The method according to claim 7,

   The antifoaming agent with respect to the total weight percentage of the total composition of the polarizing film bleaching ink composition for an inkjet printer, characterized in that it further comprises 0.01 to 5% by weight.
9. The method according to claim 7,

   Polarizing film bleaching ink composition for an inkjet printer, characterized in that the surfactant further comprises 0.1 to 5% by weight based on the total weight percentage of the total composition.
10. The method according to claim 1,

    The composition is a polarizing film bleaching ink composition for an inkjet printer, characterized in that the PVA polarizing film.
11. (1) heating the polarizing film;

    (2) bleaching the ink composition by ejecting the ink composition through the inkjet head of the inkjet printer to the heated polarizing film; And

    (3) neutralizing the bleached polarizing film;

    Discharge amount of the ink composition of the step (2) is 0.02 ~ 0.5ml / cm ² per unit area of the heated polarizing film manufacturing method of the polarizing film formed.
12. The method according to claim 11,

    Step (1) is

    Method for producing a polarizing film formed with a bleaching pattern, characterized in that carried out at a temperature of 30 ~ 100 ℃.
13. The method according to claim 11,

    The ink composition is a polarizing film manufacturing method having a bleaching pattern, characterized in that the composition of claim 1.
14. The method according to claim 13,

    The strong base includes any one or more selected from potassium hydroxide (KOH), sodium hydroxide (NaOH), calcium hydroxide (Ca (OH) ₂ and barium hydroxide (Ba (OH) ₂ ),

    The volatilization inhibitor is selected from 2-pyrrolidone, glycerin, 2-methyl-1,3-propanediol, and propylene glycol. Includes any one or more of

    The viscosity increasing agent is a polarizing film having a bleaching pattern, characterized in that it comprises any one or more selected from glycerin (Glycerine), polyvinylpyrrolidone (Polyvinylpyrrolidone) and 2-hydroxyethyl cellulose (2-Hydroxyethyl cellulose) Manufacturing method.
15. The method according to claim 13,

    5 to 30% by weight of the strong base, the volatilization inhibitor 1 to 50% by weight and the viscosity enhancer 0.1 to 5% by weight relative to the total weight of the ink composition, a method of manufacturing a polarizing film with a bleaching pattern is formed.
16. The method according to claim 13,

    Method for manufacturing a polarizing film formed with a bleaching pattern characterized in that it further comprises any one or more selected from the antifoaming agent and the surfactant in the ink composition.
17. The method according to claim 16,

    The antifoaming agent further comprises 0.01 to 5% by weight based on the total weight of the ink composition,

    The surfactant is a polarizing film manufacturing method with a bleaching pattern characterized in that it further comprises 0.1 to 5% by weight.
18. The method according to claim 11,

    Method for manufacturing a polarizing film with a bleaching pattern, characterized in that the interval between the droplets of the bleaching pattern formed by ejecting the ink composition is 5 ~ 508um respectively.
19. The method according to claim 11,

    The bleaching reaction is a polarizing film manufacturing method with a bleaching pattern, characterized in that the temperature is carried out for 3 to 30 seconds.
20. The method according to claim 11,

    Step (3) is a method of manufacturing a polarizing film having a bleaching pattern, characterized in that the method is carried out by a method of immersing in the neutralizing solution or applying a neutralizing solution.
21. The method of claim 20,

    The neutralization solution is water or an acid solution,

    The acidic solution is a polarizing film manufacturing method having a bleaching pattern, characterized in that it comprises any one or more selected from boric acid, nitric acid and acetic acid.
22. The method of claim 20,

    The coating method is a bleaching pattern, characterized in that carried out by any one method selected from the group consisting of spray, steam, curtain coating, inkjet coating, screen printing, bar coating, slit die coating and dip coating Formed polarizing film manufacturing method.
23. The method according to claim 11,

    After the step (3) (4) a method of manufacturing a polarizing film with a bleaching pattern, characterized in that it further comprises the step of drying.
24. The method according to claim 23,

    The drying step is a patterned polarizing film manufacturing method characterized in that it is carried out using an oven or air blowing.
25. The method according to claim 11,

    The polarizing film is a polyvinyl alcohol (PVA) film-formed polarizing film manufacturing method characterized in that the film.
26. Polarizing film formed with a bleaching pattern prepared using the composition of claim 1.
27. Display comprising the polarizing film of claim 26.