KR20150087073A - Porous adsorbent material for removing impurity ions from a liquid crystal material - Google Patents

Abstract

The present invention relates to a porous absorbent material, including a metal-organic structure particle and a cross-bonding copolymer, which is bound to the metal-organic structure particle and has a monomer unit wherein the monomer unit includes at least one alkenyl group and at least functional group selected from acid and base groups, and the functional group is used for removing impurity ions from a liquid crystal material.

Description

[0001] The present invention relates to a porous adsorbent for removing impurity ions from a liquid crystal material,

The present application is related to U.S. Provisional Patent Application Serial No. 61 / 423,977, filed December 16, 2010, U.S. Serial No. 13 / 020,462, filed on February 3, 2011, U.S. Patent No. 8,163,136, issued Apr. 24, each of which is incorporated herein by reference in its entirety.

The present invention relates to a porous adsorbent for removing impurity ions from a liquid crystal material, and more particularly, to a metal-organic frameworks particle and a copolymer having a functional group capable of removing impurity ions from a liquid crystal material To a porous sorbent material.

The impurity ions or moisture in the liquid crystal material may cause an increase in conductivity, a decrease in voltage holding ratio, a slow switching response, a gray-level, image sticking, often causing serious problems such as image flickering. In order to reduce the impurity ion concentration and / or moisture in the liquid crystal material, various methods have been proposed. One method involves the use of metal-organic frameworks (MOFs) particles as an adsorbent to remove moisture from the liquid crystal material. However, since MOF particles have a relatively small particle size, separation of the processed liquid crystal material and MOF particles through filtration using a syringe filter can be difficult and time consuming.

It is therefore an object of the present invention to provide a porous sorbent material which can overcome the above-mentioned disadvantages associated with the prior art.

According to an aspect of the present invention, there is provided a porous adsorbent for removing impurity ions from a liquid crystal material. The porous sorbent material includes metal-organic structure particles and a crosslinked copolymer bonded to the metal-organic structure particles and having monomer units. The monomer unit includes at least one alkenyl group and at least one functional group selected from the group consisting of an acid group and a base group, and the functional group can remove impurity ions from the liquid crystal material.

According to another aspect of the present invention, a method for removing impurity ions from a liquid crystal material is provided. The method comprises: preparing a porous adsorbent comprising metal-organic structure particles and a cross-linked copolymer, wherein the cross-linked copolymer is bound to the metal-organic structure and has monomer units, wherein the monomer The unit comprises at least one alkenyl group and at least one functional group selected from the group consisting of an acid group and a base group, the functional group being capable of removing impurity ions from the liquid crystal material; And mixing the liquid crystal material with the porous adsorbent to allow the porous adsorbent to adsorb the impurity ions in the liquid crystal material.

In accordance with the present invention, preferred embodiments of porous sorbents for removing impurity ions (e.g., F-, Cl-, etc.) and moisture from liquid crystal materials include metal-organic structure (MOF) particles and crosslinked copolymers Wherein the cross-linked copolymer is bonded to the metal-organic structure through interactions such as adhesive interactions, Van der Waals interactions, and chemical bonds, and the first and second monomer units and the (meth) acrylate-based monomer Unit. The first monomer unit includes at least one alkenyl group and at least one functional group selected from the group consisting of an acid group and a base group, and the functional group may remove impurity ions from the liquid crystal material. Preferably, the functional group of the first monomer unit is a sulfonic acid group.

The second monomer unit comprises two or more alkenyl groups. The sulfonate group of the first monomer unit and the ester group (-COO-) of the (meth) acrylate monomer unit may provide an adsorption function for removing water and impurity ions from the liquid crystal material.

The cross-linked copolymer has a three-dimensional network structure with interconnected vias and voids to connect with and receive the MOF particles. The MOF particles may be dispersed within the pores and connected to a pipe of the network structure and / or as part of the interconnected pipe to the network structure. The MOF particles are made of a material consisting of metal clusters connected by a multifunctional organic linker to form a three-dimensional porous network with large void volume and high inner-surface areas. However, since MOF particles usually have a relatively small particle size, they tend to cause filtration problems during the process of removing impurity ions from the liquid crystal material. Accordingly, the present invention facilitates filtration during the process of removing impurity ions from the liquid crystal material by forming a porous adsorbent having a large particle size by combining the MOF particles and the crosslinking copolymer.

Preferably, the metal-organic structure particles are Cr ₃ F (H ₂ O) ₃ O (BTC) ₂ .nH ₂ O (represented by MIL-100 (Cr)) wherein n is an integer from 20 to 36 , BTC is 1,3,5-benzenetricarboxylate), Fe ₃ F (H ₂ O) ₃ O (BTC) ₂ .nH ₂ O (represented by MIL-100 20 represents an integer of 1 to _{36), Al 3 F (H} 2 O) 3 O (BTC) 2 and _{nH 2 O (MIL-100 (} Al) expressed as a) (wherein, n is an integer of from 20 to 36), [Cr ₃ (BDC) ₃ (F) (H ₂ O) ₂ ] nH ₂ O (represented by MIL-101 (Cr)) wherein n is an integer from 20 to 36, BDC is 1,4- Dicarboxylate), Cu ₃ (BTC) ₂ (H ₂ O) ₃ , and combinations thereof. Preferably, the metal-organic structure particles have a pore size in the range of 10 to 40 A and a Brunauer-Emmett-Teller (BET) in the range of 1,000 to 6,000 m ² / g.

Preferably, the (meth) acrylate monomer unit is selected from the group consisting of butyl (meth) acrylate (BMA), lauryl (meth) acrylate, octyl (meth) acrylate, stearyl ≪ / RTI > More preferably, the (meth) acrylate monomer unit is butyl (meth) acrylate.

Preferably, the first monomer unit is selected from the group consisting of acrylamide-based monomers, vinylbenzene sulfonate-based monomers, and combinations thereof. More preferably, the first monomer unit is 2-acrylamido-2-methylpropanesulfonic acid (AMPS).

Preferably, the second monomer unit is selected from the group consisting of ethylene glycol dimethacrylate (EDMA), divinylbenzene, triallyl isocyanurate, and combinations thereof. More preferably, the second monomer unit is ethylene glycol dimethacrylate.

The volume ratio of the (meth) acrylate-based monomer units to the second monomer unit is preferably in the range of 2/3 to 4, more preferably in the range of 2/3 to 1, Can have a degree of optimal cross-linking.

The first monomer unit is present in an amount ranging preferably from 0.5 to 12 parts by weight, more preferably from 0.5 to 6 parts by weight, per 100 parts by weight of the (meth) acrylate monomer unit and the second monomer unit.

If the amount of the first monomer unit is less than 0.5 part by weight, the efficiency of removing impurity ions and moisture may not be satisfactory.

Preferably, the metal-organic structure particles are present in an amount ranging from 20 to 200 parts by weight per 100 parts by weight of the (meth) acrylate-based monomer units and the second monomer units.

The porous adsorbent of the present invention may be made of a desiccant to be in contact with a deteriorated liquid crystal material and absorb impurity ions and moisture in the deteriorated liquid crystal material. Preferably, the amount of the porous adsorbent material used does not exceed 4.8 parts by weight per 100 parts by weight of the deteriorated liquid crystal material.

Removal of impurity ions from the liquid crystal material can be carried out by a method comprising the steps of: producing the porous adsorbent; Mixing the liquid crystal material and the porous adsorbent so that the porous adsorbent absorbs the impurity ions in the liquid crystal material; And filtering the mixture of the liquid crystal material and the porous adsorbent to obtain a filtered liquid of the liquid crystal material.

The following examples and comparative examples are provided to demonstrate preferred embodiments of the present invention and should not be construed as limiting the scope of the present invention.

Example

≪ Example 1 (E1) >

0.1 mg of azobisisobutyronitrile (initiator) and 0.1 mg of 2-acrylamido-2-methylpropanesulfonic acid (AMPS) were added to a plastic tube. (7.2 μl), 10 μl (10.8 μl) of ethylene glycol dimethacrylate (EDMA), 76 μl of [hexyl (2-hydroxyethyl) dimethylammonium] tetrafluoroborate and 6 [mu] l of deionized water was added to the plastic tube. The mixture in the plastic tube was subjected to supersonic vibration for 10 minutes. 8.5 mg of [Cr ₃ (O) (BDC) ₃ (F) (H ₂ O) ₂ ] 28H ₂ O (MOF, MIL-101 (Cr)) was added to the mixture in the plastic tube. The mixture was vibrated for 15 minutes using a Vortex vibrator. The plastic tube was sealed with tape and immersed in water in a beaker. The beaker and the assembly of the plastic tube were heated in a microwave oven for about 5 minutes to induce polymerization of the mixture. After the reaction, methanol was added to the plastic tube to dissolve the unreacted material in the reaction product. The mixture was filtered using a centrifuge at 10,000 rpm for 5 minutes. The filtrate was removed from the reaction product in the plastic tube. The reaction product was repeatedly washed with methanol and filtered until the filtrate was clear. Then, the reaction product was dried at 80 DEG C for 12 hours to obtain a porous adsorbent.

≪ Examples 2 to 6 (E2 to E6)

The procedures and conditions for preparing the porous sorbents of Examples 2 to 6 were similar to those of Example 1, except for the amount of AMPS used. The compositions of the porous adsorbents of Examples 1 to 6 are shown in Table 1.

≪ Comparative Examples 1 and 2 (CE1 and CE2) >

The processing procedures and conditions for producing the porous adsorbents of Comparative Examples 1 and 2 were as follows. The procedure of Example 1 was repeated except that the porous adsorbent of Comparative Example 1 had no AMPS and the porous adsorbent of Comparative Example 2 had no MOF particles. Respectively. The compositions of the porous adsorbents of Comparative Examples 1 and 2 are shown in Table 1.

≪ Comparative Example 3 (CE3) >

The procedure and conditions for preparing the porous sorbent material of Comparative Example 3 were similar to those of Example 1, except that the porous sorbent material of Comparative Example 3 was free of cross-linked copolymer. The composition of the porous adsorbent of Comparative Example 3 is shown in Table 1.

<Performance evaluation>

The samples of Examples 1 to 6 and Comparative Examples 1 to 3 were dried in an oven at 150 DEG C for 12 hours. A liquid crystal sample of an impurity-containing liquid crystal material (i.e., deteriorated liquid crystal material) containing moisture and impurity ions was exposed to the dried samples of Examples 1 to 6 and Comparative Examples 1 to 3 for 24 hours Dispersed in a liquid crystal sample). Each mixture of the dried sample and each liquid crystal sample was filtered using a syringe filter to obtain a processed liquid crystal. Each processed liquid crystal was injected into a liquid crystal cell for performance testing. In Table 1, the pure liquid crystal material refers to the liquid crystal material before deterioration.

<Conductivity measurement>

The conductivity of each processed liquid crystal in each liquid crystal cell manufactured at different frequencies was measured using a LCR Meter (HIOKI 3522-50 LCR Hitester) at a voltage of 0.5 V _rms (V _rms is the threshold voltage of the pure liquid crystal material) And under a frequency in the range of 10 ^-1 to 10 ⁵ Hz. The measurement results are shown in Table 1.

&Lt; Ion concentration measurement >

The capacitance and conductance of each processed liquid crystal in each liquid crystal cell thus manufactured were directly measured using a LCR meter under a voltage of 50 mV _rms and a frequency in the range of 10 ^-1 to 10 ⁵ Hz. Data acquisition software LabVIEW 2011 (National Instruments) was used to calculate the capacitance and conductance data for each processed liquid crystal. The measurement results are shown in Table 1.

&Lt; Measurement of voltage holding ratio &

The voltage holding ratio (VHR) of each processed liquid crystal in each of the liquid crystal cells thus manufactured was measured using a VHR measuring device under a frame time of 16.67 ms, an amplitude of 5 V, a pulse width of 15.6 μs, and a frequency of 60 Hz Respectively. The measurement results are shown in Table 1.

Example Comparative Example E1 E2 E3 E4 E5 E6 CE1 CE2 CE3 Porous sorbent
(mg) 0.5 0.5 Furtherance EDMA
(mg) 10.2 10.2 10.2 10.2 10.2 10.2 10.2 10.2 0 BMA
(mg) 6.8 6.8 6.8 6.8 6.8 6.8 6.8 6.8 0 MIL-101 (Cr)
(mg) 8.5 8.5 8.5 8.5 8.5 8.5 8.5 0 8.5 AMPS
(mg) 0.1 0.3 0.5 1.0 2.0 1.0 0 1.0 0 Pure liquid crystal material Impurity ion concentration
(Tested at the same time on one day)
x 10 ^-11 C / cm ³ - - 1.91 1.91 1.91 - - 1.91 - Impurity ion concentration
(Tested at the same time on different days)
x 10 ^-11 C / cm ³ - - - - - 3.67 3.67 - 3.67 Impurity content
Liquid crystal material
(100 mg) Impurity ion concentration
(Tested at the same time on one day)
x 10 ^-9 C / cm ³ - - 7.04 7.04 7.04 - - 7.04 - Impurity ion concentration
(Tested at the same time on different days)
x 10 ^-9 C / cm ³ - - - - - 29.1 29.1 - 29.1 Of the processed liquid crystal material
Impurity ion concentration x 10 ^-11 C / cm ³ - - 5.67 4.94 38.6 43.5 442 689 140 VHR
(%) - - - - - 96.7 95.1 - 95.1 conductivity
(x 10 ^-9 S / cm) 1Hz 1.35 1.26 2.20 2.22 5.76 2.45 4.09 11.33 3.39 10HZ 0.44 0.32 0.53 0.65 1.54 0.54 1.47 3.38 0.97 100Hz 0.48 0.35 0.72 0.59 1.49 0.68 1.66 4.29 1.43 1000Hz 4.35 4.16 4.49 4.30 5.39 4.81 5.45 11.71 6.32

"-" indicates no data.

The ion measurement results show that the porous adsorbents of Examples 1 to 6 can reduce the concentration of impurity ions in the liquid crystal material to a level much lower than that of the porous adsorbents of Comparative Examples 1 to 3.

 It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit of the invention.

Claims (22)

A porous adsorbent for removing impurity ions from a liquid crystal material, wherein the porous adsorbent comprises
Metal-organic framework particles; And
A cross-linked copolymer bonded to the metal-organic structure particles and having a first monomer unit,
Wherein the first monomer unit comprises at least one alkenyl group, and at least one functional group selected from the group consisting of an acid group and a base group, and the functional group is capable of removing impurity ions from the liquid crystal material. The method according to claim 1,
Wherein the functional group of the first monomer unit is a sulfonic acid group. 3. The method according to claim 1 or 2,
The crosslinked copolymer further comprises a second monomer unit comprising a (meth) acrylate-based monomer and at least two alkenyl groups. 3. The method according to claim 1 or 2,
Wherein the metal-organic structure particles are Cr ₃ F (H ₂ O) ₃ O (BTC) ₂ .nH ₂ O wherein n is an integer from 20 to 36 and BTC is 1,3,5-benzenetricarboxylate _{), Fe 3 F (H 2} O) 3 O (BTC) 2 and nH ₂ O (wherein, n is an integer of from 20 to _{36), Al 3 F (H} 2 O) 3 O (BTC) 2 and nH ₂ O (Where n is an integer from 20 to 36), [Cr ₃ (O) (BDC) ₃ (F) (H ₂ O) ₂ ] nH ₂ O, Benzene dicarboxylate), Cu ₃ (BTC) ₂ (H ₂ O) _3, and combinations thereof. The method of claim 3,
Wherein the first monomer unit is selected from the group consisting of an acrylamide-based monomer, a vinylbenzene sulfonate-based monomer, and combinations thereof. 6. The method of claim 5,
Wherein the first monomer unit is 2-acrylamido-2-methylpropanesulfonic acid. The method of claim 3,
Wherein the (meth) acrylate monomer unit is selected from the group consisting of butyl (meth) acrylate, lauryl (meth) acrylate, octyl (meth) acrylate, stearyl (meth) acrylate, Porous sorbent. The method of claim 3,
Wherein said second monomer unit is selected from the group consisting of ethylene glycol dimethacrylate, divinyl benzene, triallyl isocyanurate, and combinations thereof. The method of claim 3,
Wherein the volume ratio of said (meth) acrylate-based monomer units to said second monomer unit is in the range of 2/3 to 4. The method of claim 3,
Wherein the first monomer unit is present in an amount ranging from 0.5 to 6 parts by weight per 100 parts by weight of the (meth) acrylate monomer unit and the second monomer unit. The method of claim 3,
Wherein the metal-organic structural particles are present in an amount ranging from 20 to 200 parts by weight per 100 parts by weight of the (meth) acrylate-based monomer unit and the second monomer unit. As a method for removing impurity ions from a liquid crystal material,
Preparing a porous sorbent material comprising metal-organic structure particles and a cross-linked copolymer, wherein the cross-linked copolymer is bonded to the metal-organic structure and has a first monomeric unit, wherein the first monomeric unit comprises one or more An alkenyl group, and at least one functional group selected from the group consisting of an acid group and a base group, wherein the functional group is capable of removing impurity ions from the liquid crystal material; And
And mixing the liquid crystal material with the porous adsorbent so that the porous adsorbent absorbs the impurity ions in the liquid crystal material. 13. The method of claim 12,
Further comprising filtering the mixture of the liquid crystal material and the porous adsorbent material to obtain a filtered liquid of the liquid crystal material. The method according to claim 12 or 13,
Wherein the functional group of the first monomer unit is a sulfonic acid group. 15. The method of claim 14,
Wherein the crosslinking copolymer further comprises a second monomer unit comprising a (meth) acrylate monomer unit and at least two alkenyl groups. The method according to claim 12 or 13,
Wherein the metal-organic structure particles are Cr ₃ F (H ₂ O) ₃ O (BTC) ₂ .nH ₂ O wherein n is an integer from 20 to 36 and BTC is 1,3,5-benzenetricarboxylate _{), Fe 3 F (H 2} O) 3 O (BTC) 2 and nH ₂ O (wherein, n is an integer of from 20 to _{36), Al 3 F (H} 2 O) 3 O (BTC) 2 and nH ₂ O (Where n is an integer from 20 to 36), [Cr ₃ (O) (BDC) ₃ (F) (H ₂ O) ₂ ] nH ₂ O, Benzene dicarboxylate), Cu ₃ (BTC) ₂ (H ₂ O) _3, and combinations thereof. 16. The method of claim 15,
Wherein the first monomer unit is selected from the group consisting of acrylamide-based monomers, vinylbenzene sulfonate-based monomers, and combinations thereof. 16. The method of claim 15,
Wherein the (meth) acrylate monomer unit is selected from the group consisting of butyl (meth) acrylate, lauryl (meth) acrylate, octyl (meth) acrylate, stearyl (meth) acrylate, Removal method. 16. The method of claim 15,
Wherein the second monomer unit is selected from the group consisting of ethylene glycol dimethacrylate, divinyl benzene, triallyl isocyanurate, and combinations thereof. 16. The method of claim 15,
Wherein the volume ratio of the (meth) acrylate-based monomer units to the second monomer unit is in the range of 2/3 to 4. 16. The method of claim 15,
Wherein the first monomer unit is present in an amount ranging from 0.5 to 6 parts by weight per 100 parts by weight of the (meth) acrylate monomer unit and the second monomer unit. 16. The method of claim 15,
Wherein the metal-organic structure particles are present in an amount ranging from 20 to 200 parts by weight per 100 parts by weight of the (meth) acrylate-based monomer unit and the second monomer unit.