KR20170074509A - Pre-polymer Composition for Polymer Dispersed Liquid Crystal Composite Film, Composite Film and Liquid Crystal Device Using the Same - Google Patents

Pre-polymer Composition for Polymer Dispersed Liquid Crystal Composite Film, Composite Film and Liquid Crystal Device Using the Same Download PDF

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KR20170074509A
KR20170074509A KR1020150183865A KR20150183865A KR20170074509A KR 20170074509 A KR20170074509 A KR 20170074509A KR 1020150183865 A KR1020150183865 A KR 1020150183865A KR 20150183865 A KR20150183865 A KR 20150183865A KR 20170074509 A KR20170074509 A KR 20170074509A
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acrylate
liquid crystal
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고동한
이승철
엄상열
이문복
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도레이첨단소재 주식회사
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    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L33/00—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides or nitriles thereof; Compositions of derivatives of such polymers
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    • C08L33/06—Homopolymers or copolymers of esters of esters containing only carbon, hydrogen and oxygen, which oxygen atoms are present only as part of the carboxyl radical
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J3/00—Processes of treating or compounding macromolecular substances
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    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
    • C08J5/24—Impregnating materials with prepolymers which can be polymerised in situ, e.g. manufacture of prepregs
    • G—PHYSICS
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    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1334—Constructional arrangements; Manufacturing methods based on polymer dispersed liquid crystals, e.g. microencapsulated liquid crystals

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Abstract

The present invention provides an acrylic copolymer 100 (a) copolymerized with 30 to 80% by weight of a linear or branched alkyl (meth) acrylic monomer, 10 to 30% by weight of a polar group-containing (meth) acrylic monomer and 10 to 40% (B) 0.1 to 10 parts by weight of a polyfunctional (meth) acrylate, and (c) 0.1 to 3 parts by weight of a photopolymerization initiator, based on 100 parts by weight of the polyfunctional to provide. The composite film using the composition according to the present invention has a dielectric constant in the range of 3 to 8 in the frequency range of 1 kHz to 500 kHz and has a high rate of change of the liquid crystal and a high response rate of change in transmittance depending on the presence or absence of an electric field, This is possible.

Description

TECHNICAL FIELD [0001] The present invention relates to a prepolymer composition for a polymer dispersed liquid crystal composite film, a polymer dispersed liquid crystal composite film and a liquid crystal device using the polymer dispersed liquid crystal composite film,

The present invention relates to a prepolymer composition for a polymer dispersed liquid crystal composite film, a polymer dispersed liquid crystal composite film and a liquid crystal device using the prepolymer composition, and more particularly, to a process for preparing an acrylic polymer by introducing a monomer capable of improving dielectric properties, A composition for a polymer dispersion type liquid crystal composite film which improves the response speed of change in transmittance by increasing the rate of change of liquid crystal depending on the presence or absence of an electric field and enables operation of the device even at a low driving voltage, Type liquid crystal composite film and a liquid crystal device.

The polymer dispersed liquid crystal composite film, which is a polymer dispersed liquid crystal display, is a display device in which fine liquid crystal droplets dispersed in a matrix of a polymer material react with a voltage applied from the outside to display information in the form of scattering or transmission.

The polymer dispersed liquid crystal composite film having the above-described function is a new light switching mode based on light scattering which can exert a liquid crystal function in a flexible film compared to a conventional liquid crystal display device and does not require a polarizing plate. Therefore, it can be widely used in case of selective transmission such as a smart window, which can be utilized as a partition of an indoor space or used as a skylight installed in an opening of a building, and a highway sign, a bulletin board, It can also be used as a screen, and it can be used for cars, buses, aircraft, ships, and superstructures.

The operation of the smart window, the optical switching function, is based on the principle of selective phase separation according to the electric field. The liquid crystal molecules in the polymer dispersed liquid crystal composite membrane element and the polymer cause phase separation to form small liquid crystal droplets between the polymer matrix. In a state where no voltage is applied, liquid crystal molecules in the liquid crystal droplets are arranged in an arbitrary direction, A difference occurs between the refractive index of the droplet and the refractive index of the polymer. As a result, the incident light is scattered opaque. When a voltage is applied, the liquid crystal molecules in the liquid crystal droplet align in one direction and become equal to the refractive index of the polymer. As a result, the incident light is transparently transmitted through the specimen. In the polymer dispersed liquid crystal composite film, the display is driven in a state in which light is transmitted and scattered in accordance with the presence or absence of voltage.

The polymer matrix of the polymer dispersed liquid crystal composite film having the above characteristics is generally formed by UV irradiation of a UV curing machine, in which polymer or oligomer, monomer, photoinitiator, coupling agent, etc. are added.

However, the conventional polymer-dispersed liquid crystal composite film is usually required to be made thick with a thickness of 10um or more, which is a predetermined thickness, in which the light scattering action can be exerted perfectly. When a composite film is formed with such a thickness, It is not suitable for use as a screen element because a voltage must be applied. On the other hand, if the thickness of the liquid crystal display device is lowered in order to apply a proper driving voltage for preventing the above-described problems, the driving voltage can be appropriately lowered but the scattering effect of the incident light is reduced and the contrast ratio is poor . In addition, when the thickness is reduced, the adhesion to the ITO interface may be lower than that of the composite film having a thick thickness.

Accordingly, various proposals have been made in order to solve the problems in the conventional polymer dispersed liquid crystal composite film. For example, Patent Document 1 discloses that 0.1 to 20% by weight of a polyfunctional resin, 0.1 to 99% by weight of a diluent, 0.1 to 99% by weight, and 0.1 to 99% by weight of a photoinitiator, wherein the diluent and the cross-linking agent have a composition ratio of 1:99 to 99: 1. The driving voltage and the high contrast ratio are realized. However, in the case of a polyfunctional resin based on an acrylate derivative compound, it is difficult to deviate from the basic characteristics of the acrylate, and therefore, it is difficult to greatly improve. In Patent Document 2, the polyfunctional oligomer is improved in adhesion and workability by improving the adhesion between the polymer dispersed liquid crystal composite film and the ITO conductive film as a substrate, by using urethane-based acrylate derivative compounds containing aliphatic silane, A technique for improving interfacial peeling is disclosed. However, the improvement of the low driving voltage and the contrast ratio, which are the main characteristics of the polymer dispersed liquid crystal composite film, was similar to that of the conventional liquid crystal composite film, and the functional improvement could not be expected. In addition, Patent Document 3 discloses a technique capable of applying a low driving voltage using a metal oxide layer, a metal layer structure and a composition of a first transparent electrode or a second transparent electrode. However, it is difficult to expect the improvement of the behavior of the polymer dispersed liquid crystal composite film to be greatly improved even if the resistance value of a general transparent electrode film is sufficient enough for driving and the resistance value is lowered.

Accordingly, it is an object of the present invention to provide a polymer dispersed liquid crystal composite film resin composition and a film optimized in consideration of the above problems.

Korean Patent Registration No. 10-0812276 Korean Patent Laid-Open Publication No. 2015-0097327 Korean Patent Publication No. 2015-0009220

An object of the present invention is to provide a prepolymer composition for a polymer dispersed liquid crystal composite film which improves the electrical characteristics to increase the rate of change of the liquid crystal depending on the presence or absence of an electric field, thereby improving the response speed of the transmittance change, .

Another object of the present invention is to provide a polymer dispersed liquid crystal composite film formed using the above composition.

Still another object of the present invention is to provide a liquid crystal device manufactured using the liquid crystal composite film.

The present invention provides an acrylic copolymer 100 (a) copolymerized with 30 to 80% by weight of a linear or branched alkyl (meth) acrylic monomer, 10 to 30% by weight of a polar group-containing (meth) acrylic monomer and 10 to 40% (B) 0.1 to 10 parts by weight of a polyfunctional (meth) acrylate, and (c) 0.1 to 3 parts by weight of a photopolymerization initiator, based on 100 parts by weight of the polyfunctional to provide.

The composite film formed from the composition preferably has a dielectric constant of 3 to 8 in a frequency range of 1 kHz to 500 kHz.

It is preferable that the linear or branched alkyl (meth) acrylic monomers in the composition of the (a) acrylic copolymer are at least one or more selected from alkyl (meth) acrylate monomers having 1 to 20 carbon atoms.

The (meth) acrylic monomer containing a polar group in the composition of the acrylic copolymer (a) is a monomer containing a hydroxyl group; Vinyl alcohols and allyl alcohol; Epoxy group-containing monomers; Sulfonate group-containing monomers; And phosphate group-containing monomers, or a mixture of two or more thereof.

It is preferable that the dielectric characteristic monomer in the composition of the acrylic copolymer (a) is a single type or a mixture of two or more types selected from a cyclic alkyl (meth) acrylate monomer or a nitrogen-containing (meth) acrylate.

The present invention also provides a polymer dispersed liquid crystal composite film comprising the prepolymer composition and the liquid crystal material, wherein the mixing ratio is 1:99 to 99: 1.

In the liquid crystal material, light is scattered when no electric field is applied, and light is transmitted when an electric field is applied.

According to the present invention, there is also provided a conductive film comprising: a conductive film lower plate; A polymer dispersed liquid crystal composite film in which a mixture containing a prepolymer composition for a polymer dispersed liquid crystal composite film and a liquid crystal material is coated on a lower plate of a conductive film; And a conductive film top plate laminated on the polymer dispersed liquid crystal composite film.

The composite membrane preferably has a thickness of 5 to 30 mu m.

The present invention relates to a prepolymer composition for a polymer dispersed liquid crystal composite film, which has a dielectric constant of 3.0 to 8.0 by using a copolymer using a dielectric monomer as a (meth) acrylic copolymer composition in a prepolymer, thereby improving the electrical properties of the prepolymer, The response speed of the transmittance change was improved by increasing the rate of change of the liquid crystal depending on the presence or absence of the liquid crystal.

Therefore, even if the thickness of the composite film is increased, the liquid crystal composite film behaves even at a normal driving voltage, and the speed of change of light scattering and transmission characteristics due to ON / OFF can be improved. Thus, a polymer dispersed liquid crystal composite film .

1 is a schematic cross-sectional view of a liquid crystal device employing a prepolymer composition for a liquid crystal composite film of the present invention as a liquid crystal composite film.

The prepolymer composition for polymer dispersed liquid crystal composite membrane according to the present invention comprises (a) 30 to 80% by weight of a linear or branched alkyl (meth) acrylic monomer, 10 to 30% by weight of a polar group- (B) 0.1 to 10 parts by weight of a polyfunctional (meth) acrylate and (c) 0.1 to 3 parts by weight of a photopolymerization initiator, based on 100 parts by weight of an acrylic copolymer obtained by copolymerizing 40%

The prepolymer composition for a polymer dispersed liquid crystal composite membrane of the present invention is characterized in that (a) a dielectric property is imparted through a dielectric monomer constituting an acrylic copolymer, (b) a polyfunctional (meth) acrylate in the prepolymer composition and The durability and the driving of the liquid crystal are stabilized through the initiator to realize excellent physical properties in the smart window characteristic.

The prepolymer composition for a polymer dispersed liquid crystal composite film has a dielectric constant of 3 to 8 in a frequency range of 1 kHz to 500 kHz. When the dielectric constant is less than 3, a small electric field is generated by the prepolymer composition when a voltage is applied, If it exceeds 8, excessive electric field is generated when voltage is applied and energization occurs, which causes the liquid crystal composite film to fail to operate or cause a malfunction such as a partial stain.

More specifically, the prepolymer composition for a polymer-dispersed liquid crystal composite film is characterized in that the linear or branched alkyl (meth) acrylic monomer is at least one selected from alkyl (meth) acrylate monomers having 1 to 20 carbon atoms By weight and contains 30 to 80% by weight. If it is less than 30% by weight, the cured structure of the composite film may not be formed well, resulting in poor durability. If the content exceeds 80% by weight, the durability is improved but the dielectric property is lowered and ultimately the effect of lowering the driving voltage of the composite film can not be obtained .

Examples of the (meth) acrylate monomer include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, (Meth) acrylate, isobutyl (meth) acrylate, s-butyl (meth) acrylate, t- (Meth) acrylate, isooctyl (meth) acrylate, octyl (meth) acrylate, octyl (meth) acrylate, octyl (Meth) acrylate, isodecyl (meth) acrylate, undecyl (meth) acrylate, dodecyl (meth) acrylate, Acrylate, hexa (Meth) acrylate, decyl (meth) acrylate, heptadecyl (meth) acrylate, octadecyl (meth) acrylate and nonadecyl (meth) acrylate.

It is also preferable that (a) the polar group-containing (meth) acrylic monomer in the acrylic copolymer composition contains 10 to 30% by weight. If the content of the polar group-containing (meth) acrylic monomer is less than 10% by weight, the adhesion of the conductive film with the inorganic layer of the conductive film such as ITO is lowered and the reliability evaluation fails. If the content is more than 30% by weight, The wettability is lowered.

In the above, the polar group-containing (meth) acrylic monomer may be a hydroxyl group-containing monomer; Epoxy group-containing monomers; Sulfonate group-containing monomers; And a phosphate group-containing monomer; or a mixture of two or more thereof.

Preferable examples of the (meth) acrylic monomer having a polar group include 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate and 6-hydroxyhexyl A hydroxyl group-containing monomer including a (meth) acrylate; Vinyl alcohols and allyl alcohol; Epoxy group-containing monomers including glycidyl (meth) acrylate and methyl glycidyl (meth) acrylate; Sulfonate group-containing monomers including sodium vinyl sulfonate; And phosphate group-containing monomers including 2-hydroxyethyl acryloyl phosphate; or a mixture of two or more thereof.

It is preferable that the dielectric monomer in the acrylic copolymer composition (a) contains 10 to 40% by weight. When the content of the dielectric characteristic monomer is less than 10% by weight, dielectric properties can not be realized. If the content is more than 40% by weight, adherence to the transparent electrode is lowered, which may cause reliability problems.

Wherein the dielectric characteristic monomer is selected from cyclic alkyl (meth) acrylate monomers or nitrogen-containing (meth) acrylates, or a mixture of two or more thereof. A preferred example of the cyclic alkyl (meth) acrylate monomer is a mixture of at least one type selected from the group consisting of cyclopentyl (meth) acrylate, cyclohexyl (meth) acrylate and isobonyl (meth) .

Preferred examples of the nitrogen-containing (meth) acrylate monomers include (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N-methylol (meth) acrylamide, N-methoxymethyl Amide, N-butoxymethyl (meth) acrylamide and N-hydroxyethyl (meth) acrylamide; Nitrogen-containing compounds containing N-vinyl-2-pyrrolidone, N-vinyl-2-piperidone, N-vinyl-2-caprolactam, N-vinylpiperazine, N-vinylpyrrol and N-vinylimidazole A monomer containing a nitrogen-containing heterocyclic ring selected from (meth) acrylic monomers containing a vinyl-based monomer containing a heterocyclic ring or a nitrogen-containing heterocyclic ring containing (meth) acryloylmorpholine; Amino group-containing monomers including aminoethyl (meth) acrylate, dimethylaminoethyl (meth) acrylate and t-butylaminoethyl (meth) acrylate; Cyano group-containing monomers including acrylonitrile and methacrylonitrile; An imide group-containing monomer including cyclohexylmaleimide and isopropylmaleimide; And isocyanate group-containing monomers including 2-methacryloyloxyethyl isocyanate. The term " isocyanate group-containing monomer "

If the amount of the polyfunctional (meth) acrylate (b) is less than 0.1 parts by weight, the acrylic copolymer composition will not react well with the monomer, resulting in poor curing structure and strong internal cohesion of the liquid crystal composite membrane . On the other hand, if the polyfunctional (meth) acrylate (b) is more than 10 parts by weight, the internal cohesive force becomes excessively large and the composite film film easily cracks or breaks, and stable bonds can not be induced at the interface with the transparent electrode I do not.

Preferable examples of the polyfunctional (meth) acrylate include hexanediol di (meth) acrylate, butanediol di (meth) acrylate, (poly) ethylene glycol di (meth) acrylate, (poly) propylene glycol di Acrylate, trimethylolpropane tri (meth) acrylate, neopentyl glycol di (meth) acrylate, pentaerythritol di (meth) acrylate, pentaerythritol tri (Meth) acrylate, tetramethylolmethane tri (meth) acrylate, allyl (meth) acrylate, vinyl (meth) acrylate, divinylbenzene, epoxy acrylate and polyester acrylate monomers. It is a mixture of two or more species.

The photopolymerization initiator (c) includes 0.1 to 3.0 parts by weight, preferably 0.5 to 2.0 parts by weight, based on 100 parts by weight of the acrylic copolymer composition composed of (meth) acrylate. Upon reception, it forms a radical to induce the initiation of polymerization or curing.

If the photopolymerization initiator (c) is less than 0.1 part by weight, the ultraviolet ray irradiation time must be prolonged in order to maintain the reactivity of the radical with a small number of generated radicals, and the structure produced by the radical must have a sufficient chain length and a cured structure But may contain monomers that do not participate in the reaction. On the other hand, when (c) the photopolymerization initiator (c) is contained in an amount of more than 3.0 parts by weight, a large amount of radicals are generated to form long chains and a hardened structure having good durability, and radicals remain to discolor the liquid crystal composite film, It is not preferable because bubbles are generated in reliability.

The polymer dispersed liquid crystal composite film according to the present invention is characterized in that the above-described prepolymer composition is used as a support and includes a liquid crystal material. More preferably, the mixing ratio of the prepolymer composition and the liquid crystal material is 1:99 to 99: 1. As a result, in the polymer dispersed liquid crystal composite film, the liquid crystal material is characterized in that light is scattered and turned opaque when the electric field is not applied, and when the electric field is applied, light is transmitted to form a transparent composite film.

The present invention also provides a liquid crystal device employing the prepolymer composition for a liquid crystal composite film as a liquid crystal composite film. 1 is a schematic cross-sectional view of a liquid crystal device of the present invention. Referring to FIG. 1, the polymer dispersed liquid crystal composite film film according to the present invention is a polymer dispersion type liquid crystal composite film film obtained by coating a mixture containing the above-described polymer dispersed liquid crystal composite film prepolymer composition and a liquid crystal material on the conductive film lower plate 3 A liquid crystal composite film (2), and a conductive film top plate (1) laminated on the polymer dispersed liquid crystal composite film.

In the display device, the thickness of the composite film formed of the composition is preferably 5 to 30 占 퐉. If the thickness is less than 5 탆, the light at the OFF time is not enough to scatter the light sufficiently to exhibit opaque characteristics. However, since the light has a certain transmittance, the composite film does not function as a composite film, There is a problem that the occurrence of defects increases during post-processing and the reliability is lowered. On the other hand, if the thickness is more than 30 μm, light is transmitted when the voltage is applied and the transparent film is formed. However, due to the thickness of the film, light loss and scattering occur. Accordingly, it is preferable that the prepolymer composition for a polymer dispersed liquid crystal composite membrane of the present invention has a dielectric constant of 3 to 8 in a frequency range of 1 kHz to 500 kHz and a thickness of the composite film of 5 to 30 μm.

On the other hand, the upper plate 1 and the lower plate 3 can be manufactured by using a transparent electrode material known in the art such as ITO, for example, as the first and second electrodes, respectively.

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

< Example  1>

Step 1: Preparation of resin of acrylic copolymer

55% by weight of 2-ethylhexyl acrylate (2-EHA) in a 500 ml chemical reactor equipped with a stirrer, a reflux condenser, a thermometer and a nitrogen injection device; 25% by weight of hydroxyethyl acrylate (HEA); And 20 parts by weight of 4-acryloylmorpholine (ACMO) were added. When 100 parts by weight of the mixture was added, 0.2 part by weight of a photopolymerization initiator Irgacure 184 (Ciba specialty chemicals) was added and the mixture was photopolymerized for 1 minute. Followed by partial polymerization to obtain a resin syrup.

Step 2: polymer dispersed liquid crystal Composite membrane  Production of film

4 parts by weight of hexanediol di (meth) acrylate, which is a polyfunctional (meth) acrylate, was added to 100 parts by weight of the acrylic copolymer as the base resin obtained in the above step 1, and 1.0 parts by weight of a photopolymerization initiator Irgacure 651 (Ciba specialty chemicals) 1.0 , And an acrylic polymer and a liquid crystal (E7, Merck) were mixed in a weight ratio of 4: 6 to prepare a coating solution.

The coating solution was coated on a lower plate ITO film having a thickness of 188 탆 to a thickness of 20 탆, and then the ITO film having the same thickness as the upper plate was laminated so as not to change the thickness and to prevent the uniformity from being deteriorated. Polymer Dispersed Liquid Crystal Composite Membrane Film was prepared by PIPS (Polymerization Induced Phase Separation) method using UV curing machine.

In order to proceed with the evaluation of the composite composition itself, the coating solution is coated on a polyethylene terephthalate (PET) film having a thickness of 20 탆 so that a sample is prepared using polyethylene terephthalate (PET) separately treated.

< Example  2>

In the acrylic copolymer resin production process of Step 1 of Example 1, 50 wt% of 2-HEA; 15 wt% HEA; And 35% by weight of ACMO, respectively.

< Example  3>

In the acrylic copolymer resin production process of step 1 of Example 1, 55% by weight of 2-HEA; 25 wt% HEA; And 20% by weight of isobornyl acrylate (IBOA) were copolymerized in the same manner as in Example 1 above.

< Comparative Example  1>

In the acrylic copolymer resin production process of Step 1 of Example 1, 65 wt% of 2-HEA; And 35% by weight of HEA, respectively.

< Comparative Example  2>

40% by weight of 2-HEA in the acrylic copolymer resin production process of Step 1 of Example 1 above; 15 wt% HEA; And 45% by weight of IBOA were copolymerized in the same manner as in Example 1 above.

< Comparative Example  3>

(B) 12 parts by weight of hexanediol di (meth) acrylate, which is a polyfunctional (meth) acrylate, was added in the production process of the pressure-sensitive adhesive film in Step 2 of Example 1, Respectively.

< Comparative Example  4>

Except that 3.3 parts by weight of (c) a photopolymerization initiator Irgacure 651 (Ciba specialty chemicals) was added in the step of producing the pressure-sensitive adhesive film in the step 2 of Example 1 above.

Example
One Example
2 Example
3 Comparative Example
One Comparative Example
2 Comparative Example
3 Comparative Example
4 Acrylic copolymer content
(weight%) Linear or branched
(EHA)
55
50
55
65
40
55
55 Polar group content
(HEA)
25
15
25
35
15
25
25 Dielectric Properties Monomer 1
(ACMO)
20
35
45
20
20 Dielectric Properties Monomer 2
(IBOA)
20 Polyfunctional (meth) acrylate
(Parts by weight)
4
4
4
4
4
12
4 Photopolymerization initiator
(Parts by weight 1.2 1.2 1.2 1.2 1.2 1.2 3.3 * EHA: 2-ethylhexyl acrylate
HEA: Hydroxyethyl acrylate
ACMO: 4-acryloylmorpholine
IBOA: isobornyl acrylate

< Experimental Example >

The physical properties of the liquid crystal composite films prepared in Examples 1 to 3 and Comparative Examples 1 to 4 were measured as follows, and the results are shown in Table 2 below.

1. Measurement of dielectric constant

The composite film compositions prepared in Examples 1 to 3 and Comparative Examples 1 to 4 were coated on a release-treated PET film to separately prepare a dielectric constant measurement sample. The dielectric constant of the pressure-sensitive adhesive film in a frequency range of 1 to 500 kHz was measured according to JIS K 6911 . A specific instrument used was an impedance analyzer 4294A and a permittivity measuring device 16453A (Agilent Technologies), which was 15 mm in diameter.

2. T-Peel Strength Measurement

The composite membrane compositions prepared in Examples 1 to 3 and Comparative Examples 1 to 4 were subjected to a Universal Testing Instrument Model (TM) facility, and the specimens were cut to 25 mm to measure the strength.

3. Measurement of response speed of liquid crystal

The transmittance of the liquid crystal composite film was measured under the conditions of 110 volts and 60 Hz using LCMS-200 for the response speed (flexibility, electric field response) of the liquid crystal composite films prepared in Examples 1 to 3 and Comparative Examples 1 to 4 The time to change to more than 90% was measured.

4. Measurement of driving voltage

The composite film compositions prepared in Examples 1 to 3 and Comparative Examples 1 to 4 were measured for voltage when the transmittance was increased from 10% to 90% under the condition of 0 to 110 volts and 60 Hz using LCMS-200. Since the driving voltage is affected by the thickness, it is expressed as a driving voltage per unit thickness ([mu] m).

division permittivity
(1KHz) permittivity
(500 KHz) T-Peel Strength
(g / 25 mm) Response speed
(msec) Driving voltage
(V / m) Example 1 4.7 4.5 253 8.7 0.71 Example 2 5.6 5.3 231 7.1 0.58 Example 3 4.5 4.3 262 9.1 0.76 Comparative Example 1 2.8 2.7 531 16.2 1.87 Comparative Example 2 8.3 8.1 35 6.5 0.54 Comparative Example 3 4.9 4.7 26 8.5 0.70 Comparative Example 4 5.0 4.9 29 8.1 0.69

As shown in Table 2 above, (a), depending on the type and content of the linear or branched (meth) acrylic monomer (EHA) constituting the acrylic copolymer, the polar group-containing (meth) acrylic monomer (HEA) (b) the polyfunctional (meth) acrylate, and (c) the photopolymerization initiator content, the dielectric properties of the dielectric adhesive films of Examples 1 to 3 and Comparative Examples 1 to 4 were improved, A polymer dispersed liquid crystal composite film having improved voltage could be realized.

That is, from the above results, it can be seen that, in the composition of the prepolymer for polymer dispersed liquid crystalline composite film of (a) based on an acrylic copolymer, 30 to 80% by weight of a linear or branched alkyl (meth) acrylic monomer, 10-30 wt% and 10-40 wt% of the dielectric characteristic monomers, it is possible to control the desired physical properties of the dielectric constant at a frequency of 1 to 500kHz.

Further, according to the pressure-sensitive adhesive resin composition containing the acrylic copolymer of the present invention, 0.1 to 10 parts by weight of the polyfunctional (meth) acrylate (b) and 0.1 to 3 parts by weight of the photopolymerization initiator (c) By confirming the result of satisfying the durability with excellent adhesion to the film, a prepolymer composition for a polymer dispersed liquid crystal composite film and a composite film were obtained. That is, the T-peel strength of the composite film is low due to the content of the polyfunctional acrylate (b) and the photopolymerization initiator (b) controlling the curing structure of the prepolymer composition for a polymer dispersed liquid crystal composite film and structurally unstable due to the content of the photopolymerization initiator A composite membrane could not be obtained.

As described above, the present invention provides a method of controlling the content of (a) a monomer constituting an acrylic copolymer and the content thereof, (b) a polyfunctional (meth) acrylate and (c) a photopolymerization initiator The present invention provides a polymer dispersion type liquid crystal composite membrane prepolymer composition capable of controlling the dielectric constant, and the composite membrane using the same provides improved response speed and driving voltage.

By using the above-described prepolymer composition for a polymer dispersed liquid crystal composite film in other functional displays such as a smart window, a sunroof, a billboard, a screen, a screen, and a privacy protection film, power consumption is minimized and a liquid crystal composite film having high functionality is provided.

1 .. top plate 2. Polymer Dispersed Liquid Crystal Composite Membrane 3 .. lower plate

Claims (12)

(a) 100 parts by weight of an acrylic copolymer obtained by copolymerizing 30 to 80% by weight of a linear or branched alkyl (meth) acrylic monomer, 10 to 30% by weight of a polar group-containing (meth) acrylic monomer and 10 to 40% about,
(b) 0.1-10 parts by weight of a polyfunctional (meth) acrylate and
(c) 0.1 to 3 parts by weight of a photopolymerization initiator. The prepolymer composition for a polymer dispersion type liquid crystal composite membrane according to claim 1, wherein the composite film formed from the composition has a dielectric constant of 3 to 8 in a frequency range of 1 kHz to 500 kHz. The acrylic copolymer according to claim 1, wherein the linear or branched alkyl (meth) acrylic monomer (a) in the composition of the acrylic copolymer is at least one selected from alkyl (meth) acrylate monomers having 1 to 20 carbon atoms Wherein the polymer dispersed liquid crystal composite film is a liquid crystal polymer. 4. The composition according to claim 3, wherein the linear or branched alkyl (meth) acrylic monomer is at least one selected from the group consisting of methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, Butyl (meth) acrylate, isobutyl (meth) acrylate, isobutyl (meth) acrylate, s-butyl (Meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (Meth) acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate, undecyl (meth) acrylate, dodecyl Pentadecyl (meth) (Meth) acrylate, heptadecyl (meth) acrylate, octadecyl (meth) acrylate, and nonadecyl (meth) acrylate, or a mixture of two or more thereof By weight based on the total weight of the prepolymer composition. The acrylic copolymer according to claim 1, wherein the (meth) acrylic monomer having a polar group in the composition of the acrylic copolymer (a) is at least one selected from the group consisting of 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) Hydroxyl group-containing monomers including butyl (meth) acrylate and 6-hydroxyhexyl (meth) acrylate; Vinyl alcohols and allyl alcohol; Epoxy group-containing monomers including glycidyl (meth) acrylate and methyl glycidyl (meth) acrylate; Sulfonate group-containing monomers including sodium vinyl sulfonate; And phosphate group-containing monomers comprising 2-hydroxyethyl acryloyl phosphate. 2. The prepolymer composition for a polymer dispersed liquid crystal composite membrane according to claim 1, The method according to claim 1, wherein the dielectric monomer (a) in the composition of the acrylic copolymer is selected from the group consisting of cyclic alkyl (meth) acrylate monomers and nitrogen-containing (meth) acrylates,
Wherein the cyclic alkyl (meth) acrylate monomer has at least one mixed form selected from the group consisting of cyclopentyl (meth) acrylate, cyclohexyl (meth) acrylate and isobornyl (meth)
(Meth) acrylate, N, N-dimethyl (meth) acrylamide, N-methylol (meth) acrylamide, N- Monomers including butoxymethyl (meth) acrylamide and N-hydroxyethyl (meth) acrylamide; Nitrogen-containing compounds containing N-vinyl-2-pyrrolidone, N-vinyl-2-piperidone, N-vinyl-2-caprolactam, N-vinylpiperazine, N-vinylpyrrol and N-vinylimidazole A monomer containing a nitrogen-containing heterocyclic ring selected from (meth) acrylic monomers containing a vinyl-based monomer containing a heterocyclic ring or a nitrogen-containing heterocyclic ring containing (meth) acryloylmorpholine; Amino group-containing monomers including aminoethyl (meth) acrylate, dimethylaminoethyl (meth) acrylate and t-butylaminoethyl (meth) acrylate; Cyano group-containing monomers including acrylonitrile and methacrylonitrile; An imide group-containing monomer including cyclohexylmaleimide and isopropylmaleimide; And isocyanate group-containing monomers including 2-methacryloyloxyethyl isocyanate. 2. The prepolymer composition for a polymer dispersed liquid crystal composite membrane according to claim 1, wherein the isocyanate group-containing monomers include 2-methacryloyloxyethyl isocyanate. The composition of claim 1, wherein (b) the polyfunctional (meth) acrylate is selected from the group consisting of hexanediol di (meth) acrylate, butanediol di (meth) acrylate, (poly) ethylene glycol di (meth) Propylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, pentaerythritol di (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (Meth) acrylate, vinyl (meth) acrylate, divinylbenzene, epoxy acrylate and polyester acrylate monomers such as trimethylolpropane tri (meth) acrylate, tetramethylol methane tri Or a mixed type of two or more kinds selected from the group consisting of the polymerizable liquid crystal compound and the liquid crystal polymer. The photopolymerization initiator according to claim 1, wherein the photopolymerization initiator (c) is a benzoin ether photopolymerization initiator, an acetophenone photopolymerization initiator, an? -Ketol photopolymerization initiator, an aromatic sulfonyl chloride photopolymerization initiator, a photoactive oxime photopolymerization initiator, , A benzophenone photopolymerization initiator, a ketal photopolymerization initiator, and a thioxanthone photopolymerization initiator. The prepolymer composition for a polymer dispersed liquid crystal composite membrane according to any one of claims 1 to 3, 9. A polymer dispersed liquid crystal composite film comprising a prepolymer composition according to any one of claims 1 to 8 and a liquid crystal material, wherein the mixing ratio is 1:99 to 99: 1. The polymer dispersed liquid crystal composite film according to claim 9, wherein the liquid crystal material is light scattered when an electric field is not applied and light is transmitted when an electric field is applied. A conductive film lower plate;
A polymer dispersed liquid crystal composite film in which a mixture comprising a prepolymer composition for a polymer dispersed liquid crystal composite film according to any one of claims 1 to 8 and a liquid crystal material is coated on the lower plate of the conductive film;
And a conductive film top plate laminated on the polymer dispersed liquid crystal composite film. The liquid crystal device according to claim 11, wherein the composite film has a thickness of 5 to 30 占 퐉.
KR1020150183865A 2015-12-22 2015-12-22 Pre-polymer Composition for Polymer Dispersed Liquid Crystal Composite Film, Composite Film and Liquid Crystal Device Using the Same KR20170074509A (en)

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CN109143623A (en) * 2018-08-27 2019-01-04 华南师范大学 A kind of infrared external reflection device and preparation method thereof
KR20200104481A (en) 2019-02-26 2020-09-04 주식회사 디케이티 The polymer dispersed liquid crystal display device
CN112130361A (en) * 2019-06-25 2020-12-25 深圳市诚德利科技有限公司 Ultrathin light adjusting film for vehicle and preparation method
CN112622377A (en) * 2020-12-14 2021-04-09 北京大学 Preparation method of optical diffusion film based on photo-curing polymer dispersion liquid crystal system
KR20210052008A (en) * 2019-10-31 2021-05-10 주식회사 엘지화학 Acrylic adhesive composition, acrylic adhesives thermally cured therefrom, a decoration glass panel using the same
KR20210064876A (en) * 2019-11-26 2021-06-03 이상섭 Pdlc composition and pdlc film using thereof
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Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109143623A (en) * 2018-08-27 2019-01-04 华南师范大学 A kind of infrared external reflection device and preparation method thereof
CN109143623B (en) * 2018-08-27 2021-08-10 华南师范大学 Infrared reflection device and preparation method thereof
KR20200104481A (en) 2019-02-26 2020-09-04 주식회사 디케이티 The polymer dispersed liquid crystal display device
CN112130361A (en) * 2019-06-25 2020-12-25 深圳市诚德利科技有限公司 Ultrathin light adjusting film for vehicle and preparation method
KR20210052008A (en) * 2019-10-31 2021-05-10 주식회사 엘지화학 Acrylic adhesive composition, acrylic adhesives thermally cured therefrom, a decoration glass panel using the same
KR20210064876A (en) * 2019-11-26 2021-06-03 이상섭 Pdlc composition and pdlc film using thereof
CN112622377A (en) * 2020-12-14 2021-04-09 北京大学 Preparation method of optical diffusion film based on photo-curing polymer dispersion liquid crystal system
KR20220146028A (en) 2021-04-23 2022-11-01 주식회사 디케이티 The polymer dispersed liquid crystal display device

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