KR20110012333A - Polymer composition for dye-based polarized film, polarized film using the same and method for preparing the same - Google Patents

Abstract

PURPOSE: A resin composition for a dye-based polarized film is provided to maximize molding processability by lowering a melting temperature and a melting point of a polymer and arrangement efficiency of dichroic dye while maintaining thermal stability. CONSTITUTION: A resin composition for a dye-based polarized film includes a thermoplastic resin, dichromatic dye and plasticizer. The plasticizer is one or more selected from the group consisting of phthalic acid, polyester, trimellitic acid, epoxy, aliphatic, and phosphate-based plasticizers.

Description

Resin composition for dye-based polarizing film, polarizing film using the same and manufacturing method of the polarizing film {POLYMER COMPOSITION FOR DYE-BASED POLARIZED FILM, POLARIZED FILM USING THE SAME AND METHOD FOR PREPARING THE SAME}

The present invention relates to a resin composition for a dye-based polarizing film, a polarizing film using the same and a manufacturing method of the polarizing film. More specifically, a resin composition for a dye-based polarizing film which enables the alignment of the dichroic dyes in the polarizing film efficiently even at a general drawing process temperature by lowering the viscosity of the polymer including a plasticizer and the polarizing film and the polarizing light using the same. A method for producing a film.

As the modern industrial society develops into an advanced information age, the importance of the electronic display as a medium for delivering various information with the remarkable development of the knowledge information industry is increasing day by day. Therefore, the polarizing film functions as part of a flat panel display panel such as an LCD or an organic EL.

Currently developed polarizing films are classified into various types according to the phenomenon of polarization and the method of making them. Among them, iodine molecules or dichroic dyes having dichroism in a transparent PVA (polyvinyl alcohol) film are suitable for mass production. Polymeric dichroic molding using molecules is typically used. The other type of polarizing film is a dye-based polarizing film developed by supplementing the disadvantage that the iodine-based PVA film is easily sublimed in a region of low durability and high temperature and high humidity. Dye-based polarizing film is used as a high-durability polarizing film in LCDs requiring high durability because it has a high durability due to the small change in optical properties even under high temperature and high humidity conditions. In addition, since the dye-based polarizing film is relatively easy to control the absorption wavelength according to the color can be produced in a variety of color polarizing film is used in many other fields. Generally used polarizing film uses a polyvinyl alcohol film (polarizing element) in which iodine or a dichroic substance is dyed. However, a protective layer is formed to prevent deformation of the film due to high sublimation and low durability of iodine. Generally, there is no birefringence, high light transmittance, no wavelength dependence, high heat resistance and mechanical strength, and protection of the polarizing element A trilayer structure, in which a film such as triacetate cellulose (TAC), which acts as a sieve, is bonded to both sides of a polarizing element, is used in the most general form. The polarizing film made as described above is a film that changes the unpolarized light into linearly polarized light and transmits only the light vibrating in one direction of the incident light, and has a polarizing function that absorbs the light vibrating in the other direction. In particular, when the unpolarized light emitted from the backlight of the LCD module enters only the linearly polarized light through the polarizing film into the liquid crystal cell, the intensity of transmitted light is controlled according to the degree of rotation of the polarization axis of the incident light, and gray scale expression between black and white is shown. This is one of the key materials that makes this possible.

Through the above principle, by dividing the iodine and the dichroic dye to arrange the iodine or the dichroic dye molecules in parallel with the stretching direction, a dichroic dye-based polarizing film uniaxially or biaxially stretched is obtained. In addition, in order to produce a polarizing film by mixing a dichroic dye in a thermoplastic resin, it is necessary to align the dichroic dye serving as a polarizer in a desired direction. In this case, the conventional film extrusion process is not effective alignment of the dichroic dye is a separate stretching process through this can increase the degree of alignment of the polarizing film. However, the alignment direction of the thermoplastic resin by stretching and subsequent alignment and dispersion of adjacent dye molecules are less efficient than conventional iodine and PVA combinations. That is, in the dye-based polarizing film, since the dichroic dye mixed in the thermoplastic resin is not sufficiently aligned in the film extrusion process, the stretching process is required to align it, this stretching process is a polymer constituting the film Although the movement of is performed at a temperature that is possible, the alignment of the polarizer is not efficient because of the high viscosity of the polymer at the general stretching process temperature. Therefore, in order to increase the effective alignment of the polarizing film, the stretching process is performed at a high temperature, in this case, the thermal stability of the polymer, and the drawback has emerged as a problem that does not meet the mechanical properties of the stretchable level.

Therefore, in recent studies, attempts to solve the problems of existing polarizing films using dichroic dyes have been continued to solve the above problems.

It is an object of the present invention to provide a resin composition for a dye-based polarizing film, which enables to align the dichroic dye in the polarizing film efficiently even at a general stretching process temperature by lowering the viscosity of the polymer.

Another object of the present invention to provide a method for producing a dye-based polarizing film using the resin composition.

Still another object of the present invention is to provide a dye-based polarizing film prepared using the resin composition.

Still another object of the present invention is to provide a display product using the dye-based polarizing film as a component.

The resin composition for a dye-based polarizing film of the present invention for achieving the above object includes a thermoplastic resin, a dichroic dye and a plasticizer. In this case, at least one selected from the group consisting of phthalic acid, polyester, trimellitic acid, epoxy, aliphatic and phosphite plasticizers may be used as the plasticizer.

On the other hand, the manufacturing method of the dye-based polarizing film of the present invention is a method of manufacturing a dye-based polarizing film comprising the step of extruding a mixture of thermoplastic resin, dichroic dye and stretching the extruded film, when kneading It is characterized by the addition of a plasticizer. At this time, in order to reduce the agglomeration of the plasticizer and the frictional heat therein, the plasticizer is separately injected.

The resin composition for the polarizing film of the present invention can be maximized to reduce the melting temperature and melt viscosity of the polymer easily by molding by adding a plasticizer to the resin composition for the dye-based polarizing film, and further increase the temperature. It was possible to carry out the stretching process without the need. As a result, by maximizing the alignment efficiency of the dichroic dye included in the polarizing film while maintaining the thermal stability of the dye molecules, it is possible to manufacture a dye-based polarizing film with improved polarization and transmittance.

The resin composition for the dye-based polarizing film of the present invention includes a thermoplastic resin, a dichroic dye and a plasticizer.

In this case, the thermoplastic resin may be selected from the thermoplastic resins used in the conventional dye-based polarizing film. Preferably polycarbonate (PC), polyethylene terephthalate (PET), amorphous polyethylene terephthalate (APET), polypropylene terephthalate (PPT), polynaphthalene terephthalate (PEN), polyethylene terephthalate glycerol (PETG), poly Cyclohexylenedimethylene terephthalate (PCTG), modified triacetylcellulose (TAC), cycloolefin polymer (COP), cycloolefin copolymer (COC), cyclopentadiene polymer (DCPD), cyclopentadiene polymer (CPD) ), Polymethyl methacrylate (PMMA), polyimide (PI), polyarylate (PAR), polyether sulfone (PES), polyetherimide (PEI), silicone resin, fluorocarbon resin and modified epoxy resin One or more selected from can be used.

Next, the dichroic salt may be used without limitation as long as it is used in the manufacture of a conventional dye-based polarizing film, preferably, an anthraquinone-based, azo-based dichroic dye is used Can be.

Finally, the plasticizer added to the resin composition for dye-based polarizing film of the present invention is preferably compatible with the dichroic dye and the thermoplastic polymer, has a molecular weight of 250 to 30000, and has a repeating unit. If the molecular weight is larger or smaller than this, the volatilization transition can occur and may also cause problems with thermal stability. In addition, also in the film by melt extrusion, the use of a plasticizer can be expected to have a useful effect of improving thermal stability, water resistance, and flexibility of the polymer. As a result, the plasticizer prevents the proximity of the molecular chain during the extrusion of the thermoplastic resin, thereby widening the interval between molecules, making the movement of the molecular chain easy and increasing flexibility. This can be expected to maximize the alignment of the dye by the dichroic pigments are aligned during the stretching process, the space of movement and alignment is widened.

It is preferable that it is thermally compatible with the thermoplastic resin used and stable, and the decomposition initiation temperature is 100 to 350 ° C, and preferably 200 to 350 ° C showing thermal stability in compatibility with the thermoplastic resin. . If the decomposition temperature does not reach 100 ° C., the compatibility with the plasticizer and the resins is inferior, and if it exceeds 350 ° C., the volatilization problem of the plasticizer is disadvantageous. As such, in the case of extrusion kneading at a high temperature, it is desirable to minimize the time so as not to adversely affect the product.

The amount of plasticizer added is sufficient so as not to adversely affect the mechanical, chemical and optical properties of the polarizing film to be produced. Preferably, 0.1 to 20 parts by weight is suitable for 100 parts by weight of the thermoplastic resin to be used. It is especially preferable that it is 0.1-5 weight part. If it is less than 0.1 or more than 20 parts by weight, the transition to the surface of the polarizing film may be severe or may adversely affect physical properties such as clouding, sweating, and extraction and should be appropriately selected within the range. As the kind of plasticizer, one or more selected from the group consisting of phthalic acid, polyester, trimellitic acid, epoxy, aliphatic and phosphite and plasticizers can be used. Here, the aliphatic and phosphite plasticizers are more fluid and volatile than other plasticizers, so they are inferior in physical properties. Therefore, it is generally used in a mixed form with other plasticizers. At this time, as the phthalic acid-based plasticizer, di-butyl phthalate (DBP), di-2-ethylhexyl phthalate (DEHP.) Di-isononyl phthalate (DINP), di-isodecyl phthalate (DIDP), di-isooctyl phthalate ( DIOP), di-caprylphthalate (DCP), di-n-octylphthalate (DOP), di-2-ethylhexylisophthalate (DOIP), di-2-ethylhexyl terephthalate (DOTP), di-isononyl Phthalate (DIHP), di-n-C6, C8, C10 phthalate (NHDP), di-linear-C7, C9, C11 phthalate (NHUP), di-tridecylphthalate (DTDP), di-iso-C11, C12, One or more selected from the group consisting of C13 phthalate (UDP) and di-linear-C11 phthalate (DUP) can be used. Moreover, as said polyester plasticizer, poly (ethylene glycol / adipic acid), poly (propylene glycol / adipic acid) ester, poly (1, 6- hexanediol / adipic acid) ester, poly (propylene) At least one selected from the group consisting of recall / phthalic acid) esters, poly (1,3-butanediol / adipic acid) esters, poly (1,3-butanediol / sebacic acid) esters and poly (propylene glycol / terephthalic acid) esters This can be used.

On the other hand, the manufacturing method of the dye-based polarizing film of the present invention in the conventional manufacturing method of the dye-based polarizing film comprising the step of extruding a mixture of thermoplastic resin, dichroic dye, and stretching the extruded film, It is characterized by additionally adding a plasticizer during kneading. At this time, the kneading time and temperature is very important in adding the plasticizer during kneading. Absorption time varies depending on the kneading temperature and the content of the plasticizer. In particular, the higher the content of the plasticizer, the lower the absorption time. As a result, agglomeration phenomenon and heat of friction inside may be greatly generated, and thus it is advantageous to divide it in order to prevent this. In addition, the above principle is applied in the step of kneading or tumbling the thermoplastic resin and the plasticizer before the extrusion process.

The resin composition for the dye-based polarizing film and the dye-based polarizing film prepared by the manufacturing method of the present invention can be applied to a display and a liquid crystal display of a variety of products. For example, a photoluminescence liquid crystal display polarizing plate, a spectroscopic analysis device such as a fluorescence spectrophotometer, a defect inspection device due to the confusion of the orientation of a display such as an LCD, and the like.

Hereinafter, the present invention will be described in more detail with reference to Examples. This embodiment is intended to illustrate the present invention in more detail, and the scope of the present invention is not limited to these examples.

≪ Example 1 >

To 100 parts by weight of polyethylene terephthalate glycerol (PETG), 0.2 parts by weight of Disperse red 60 was kneaded as an anthraquinone dichroic dye. Before the extrusion process, 0.1 parts by weight of a plasticizer and di-2-ethylhexylphthalate (DOP) were kneaded into the PETG and dichroic dye mixture under a metering condition using a pump. The kneaded resin was extruded at 270 ° C. to prepare a 300 μm thick film. This was stretched five times at a temperature of 100 ℃ higher than room temperature to prepare a dye-based polarizing film.

<Example 2>

A dye-based polarizing film was prepared in the same manner as in Example 1, except that the amount of the plasticizer added in Example 1 was mixed to 1 part by weight with respect to PETG.

Comparative Example 1

0.2 parts by weight of a dichroic dye (Disperse red 60) was mixed with respect to 100 parts by weight of PCTG, followed by extrusion at 270 ° C. to prepare a 300 μm thick film.

The polarization and transmittance of the films prepared in Examples 1 and 2 and Comparative Examples were measured with a JASCO V7100 spectrophotometer, and the results are summarized in Table 1 below.

<Table 1> Polarization degree and transmittance measurement results of the dye-based polarizing film of the present invention

division % Polarization Permeability (%) Example 1 86 41 Example 2 91 39 Comparative Example 1 75 35

From the results of Table 1, the polarizing films of Examples 1 and 2 prepared by performing the plasticizer addition process confirmed a significantly improved polarization degree while performing at a temperature lower than the usual stretching temperature, the transmission was also improved. In other words, when the force between molecules is reduced by heat due to the addition of plasticizer in the thermoplastic resin, the dichroic pigment during stretching is activated by the movement of the dichroic pigment by the space between molecules caused by the plasticizer obstructing the access of the molecular chain. The polarization result shows that the alignment of is further improved.

While the invention has been shown and described with reference to certain exemplary embodiments thereof, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined by the appended claims.

Claims (12)

A resin composition for a dye-based polarizing film comprising a thermoplastic resin, a dichroic dye and a plasticizer. The method of claim 1, wherein the thermoplastic resin is polycarbonate (PC), polyethylene terephthalate (PET), amorphous polyethylene terephthalate (APET), polypropylene terephthalate (PPT), polynaphthalene terephthalate (PEN), polyethylene tere Phthalate glycerol (PETG), polycyclohexylenedimethylene terephthalate (PCTG), modified triacetylcellulose (TAC), cycloolefin polymer (COP), cycloolefin copolymer (COC), dicyclopentadiene polymer (DCPD), Cyclopentadiene polymer (CPD), polymethylmethacrylate (PMMA), polyimide (PI), polyarylate (PAR), polyethersulfone (PES), polyetherimide (PEI), silicone resins, fluororesins and The resin composition for the dye-based polarizing film, characterized in that at least one selected from the group consisting of a modified epoxy resin. The resin composition of claim 1, wherein the dichroic dye is at least one selected from the group consisting of anthraquinone-based and azo-based dyes. The dye-based polarizing film of claim 1, wherein the plasticizer is at least one selected from the group consisting of phthalic acid, polyester, trimellitic acid, epoxy, aliphatic and phosphite plasticizers. Resin composition. The resin composition for a dye-based polarizing film of claim 4, wherein the decomposition start temperature of the plasticizer is 100 to 350 ° C. The phthalic acid-based plasticizer is a di-butyl phthalate (DBP), di-2-ethylhexyl phthalate (DEHP.) Di-isononyl phthalate (DINP), di-isodecyl phthalate ( DIDP), di-isoctylphthalate (DIOP), di-caprylphthalate (DCP), di-n-octylphthalate (DOP), di-2-ethylhexyl isophthalate (DOIP), di-2-ethylhexyl tere Phthalate (DOTP), di-nononylphthalate (DIHP), di-n-C6, C8, C10 phthalate (NHDP), di-linear-C7, C9, C11 phthalate (NHUP), di-tridecylphthalate (DTDP) Resin composition for the dye-based polarizing film, characterized in that at least one selected from the group consisting of di-iso-C11, C12, C13 phthalate (UDP) and di-linear-C11 phthalate (DUP). The method according to claim 4, wherein the polyester plasticizer includes poly (ethylene glycol / adipic acid), poly (propylene glycol / adipic acid) ester, poly (1,6-hexanediol / adipic acid) ester, In the group consisting of poly (propylene glycol / phthalic acid) ester, poly (1,3-butanediol / adipic acid) ester, poly (1,3-butanediol / sebacic acid) ester and poly (propylene glycol / terephthalic acid) ester Resin composition for the dye-based polarizing film, characterized in that at least one selected. The resin composition of claim 1, wherein the amount of the plasticizer is 0.1 to 20 parts by weight based on 100 parts by weight of the thermoplastic resin. In the method for producing a dye-based polarizing film comprising the step of extruding a mixture of a thermoplastic resin, a dichroic dye, and stretching the extruded film, dye-based polarization, characterized in that additional plasticizer is added during kneading Method for producing a film. 10. The method according to claim 9, wherein the additional injection of the plasticizer is a split injection method. Dye-based polarizing film prepared using the resin composition according to claim 1. Display product using the dye-based polarizing film according to claim 11 as a component.