JP2000154251A - Photocurable resin composition, sealing agent for liquid crystal pour port, and liquid crystal display cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a resin composition which can give a cured product which does not soften even at a high temperature and a high humidity and has high adhesive force and a low moisture permeability by mixing an ester-bond-free polythiol compound with a polyene compound having at least two C-C double bonds and a photopolymerization initiator. SOLUTION: The polythiol compound used is a polyene/polythiol adduct, for example, desirably, an adduct of a cyclic sulfide or a 1,4-dithian-ring- containing polythiol compound with triallyl isocyanurate or triallyl cyanurate. The polyene compound used is desirably triallyl cyanurate or triallyl isocyanurate. The mixing ratio of the polythiol compound to the polyene compound is desirably 5:1 to 1:5 in terms of a molar ratio of the thiol groups to the double bonds. The amount of the photopolymerization initiator used is desirably 0.0001-10 pts.wt. per 100 pts.wt. in total, polythiol compound and polyene compound.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a photocurable resin composition, a liquid crystal injection port sealing agent comprising the photocurable resin composition,
Further, the present invention relates to a liquid crystal display cell using the liquid crystal filler sealing agent.

[0002]

2. Description of the Related Art In a liquid crystal display cell, two transparent substrates with electrodes are opposed to each other at a predetermined interval, and the periphery thereof is sealed with an appropriate sealing member to form a cell, which is provided in a part thereof. Liquid crystal is injected into the cell from the liquid crystal injection port thus obtained, and the liquid crystal injection port is sealed using a liquid crystal injection port sealing agent.

Heretofore, a one-part or two-part curable epoxy resin liquid or a photo-curable acrylic resin liquid has been widely used as a liquid crystal injection port sealing agent. However, the one-part curable epoxy resin liquid requires long-time heating at a high temperature, resulting in poor productivity, and the two-part curable epoxy resin liquid requires time and effort to mix the main agent and the curing agent. In addition, it must be used within a certain time after mixing, and the workability is particularly poor. The photo-curable acrylic resin liquid is
Although excellent in workability and productivity, it has strong interaction with liquid crystal, contaminates liquid crystal and causes color unevenness, and has poor surface curability, stickiness remains on the cured surface, and easily adheres dust and dirt. Was something.

[0004] In order to solve such problems, a photocurable resin composition containing polythiol has been proposed as a liquid crystal injection port sealing agent.
656, JP-A-6-306172, etc.
A liquid crystal injection port sealing agent comprising a polythiol compound, a polyene compound and a photopolymerization initiator is disclosed. But,
These also decompose the ester bond part under high temperature and high humidity, the resin is softened, the adhesive strength is weak, the moisture permeability of the resin is large, water is allowed to enter inside, the void is generated in the liquid crystal injection port, There is a problem that the liquid crystal may be contaminated depending on the type of the liquid crystal, and it has not been sufficiently satisfactory.

[0005]

SUMMARY OF THE INVENTION In view of the above, the present invention provides a liquid crystal injection port sealant which does not soften even under high temperature and high humidity, has a high adhesive strength, has a low moisture permeability, It is an object of the present invention to provide a photocurable resin composition that does not generate voids in a liquid crystal injection port and does not contaminate liquid crystals, a liquid crystal injection port sealant using the same, and a liquid crystal display cell.

[0006]

The present invention comprises a polythiol compound containing no ester bond, a polyene compound having two or more carbon-carbon double bonds in one molecule, and a photopolymerization initiator. It is a photocurable resin composition characterized by the following. Hereinafter, the present invention will be described in detail.

The photocurable resin composition of the present invention comprises a polythiol compound containing no ester bond, a polyene compound having two or more carbon-carbon double bonds in one molecule,
And a photopolymerization initiator.

Examples of the polythiol compound containing no ester bond include aliphatic polythiols such as ethanedithiol, propanedithiol, hexamethylenedithiol, decamethylenedithiol, tolylene-2,4-dithiol; and aromatic polythiols such as xylenedithiol. Diglycol dimercaptan, triglycol dimercaptan, tetraglycol dimercaptan, thiodiglycol dimercaptan, thiotriglycol dimercaptan, thiotetraglycol dimercaptan;
And cyclic sulfide compounds such as 1,4-dithiane-containing polythiol compounds.

Also, polyene-added polythiol compounds in which the thiol group of the polythiol compound containing no ester bond is bonded to the double bond portion of the polyene compound having two or more carbon-carbon double bonds in one molecule, etc. Examples of the polythiol compound not containing an ester bond include the above. That is, in the present specification, the polythiol compound containing no ester bond may be one having no thiol group due to the reaction of the polythiol compound with another compound. Examples of the polyene compound having two or more carbon-carbon double bonds in one molecule include the same as the polyene compound having two or more carbon-carbon double bonds in one molecule described below. .

[0010] Among the above cyclic sulfide compounds,
A 1,4-dithiane ring-containing polythiol compound is more preferred. As the 1,4-dithiane ring-containing polythiol compound, for example, the following general formula (I);

[0011]

Embedded image

(Wherein, n represents an integer of 1 to 5). Specific examples of the polythiol compound represented by the general formula (I) include, for example,
2,5-dimercaptomethyl-1,4-dithiane, 2,
5-dimercaptoethyl-1,4-dithiane, 2,5-
Dimercaptopropyl-1,4-dithiane, 2,5-dimercaptobutyl-1,4-dithiane and the like can be mentioned.

As the polyene-added polythiol compound, for example, a compound of a cyclic sulfide compound or a polythiol compound containing a 1,4-dithiane ring and triallyl isocyanurate or triallyl cyanurate is preferable. By using such a polyene-added polythiol compound, liquid crystal contamination can be further reduced.

The polyene compound used in the present invention is not particularly limited as long as it is a polyfunctional compound having two or more carbon-carbon double bonds. For example, polyene compounds such as allyl alcohol derivatives and (meth) acrylic acid may be used. Esters with a hydric alcohol, urethane acrylate, divinylbenzene, and the like are included.

The above allyl alcohol derivative is not particularly restricted but includes, for example, triallyl cyanurate, triallyl isocyanurate, diallyl maleate, diallyl adipate, diallyl phthalate, triallyl trimellitate, tetraallyl pyromellitate, glycerin diallyl Ether, trimethylolpropane diallyl ether, pentaerythritol, diallyl ether and the like.

The polyhydric alcohol used in the esters of the (meth) acrylic acid and the polyhydric alcohol is not particularly limited. For example, ethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexane Diol, glycerin, trimethylolpropane,
Pentaerythritol, sorbitol and the like.
Among the polyene compounds, triallyl cyanurate and triallyl isocyanurate are preferred.

In the photocurable resin composition of the present invention, the mixing ratio of the polythiol compound to the polyene compound having two or more carbon-carbon double bonds in one molecule is not particularly limited. The molar ratio of the thiol group to the carbon-carbon double bond of the polyene compound having two or more carbon-carbon double bonds in one molecule is 5: 1 to 1
It is preferable to mix them in a ratio of 1: 5. A more preferred molar ratio is around 1: 1.

The polymerization initiator used in the present invention is not particularly restricted but includes, for example, benzophenone, p-aminobenzophenone, p, p'-dimethylaminobenzophenone, methyl orthobenzoyl benzoate, 4-benzoyl-4'-methyl Benzophenone photopolymerization initiators such as diphenyl sulfide, acetophenone, benzaldehyde, benzyldimethyl ketal, 2-hydroxy-2-methyl-1-phenylpropan-1-one,
Methyl-1- [4- (methylthio) phenyl] -2-morpholinopropane-1, oligo [2-hydroxy-2-
Acetophenone-based photopolymerization initiators such as methyl-1- {4- (1-methylvinyl) phenyl} propanone], and benzoin ether-based photopolymerization initiators such as benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether and benzoin isobutyl ether. , 2, 2'-
Azo compounds such as azobisisobutyronitrile, diazo compounds such as diazoaminobenzene, 4,4′-diazidostilbene-p-phenylenebisazide, isopropylthioxanthone, diethylthioxanthone, acylphosphine oxide, benzyl, camphorquinone , Anthraquinone, Michler's ketone and the like.

In the photocurable resin composition of the present invention, the photopolymerization initiator is compounded in an amount of 100 times the total amount of the polythiol compound and the polyene compound having two or more carbon-carbon double bonds in one molecule. 0.0001 to parts by weight
The range is preferably from 10 to 10 parts by weight, more preferably from 0.05 to 5 parts by weight. The above-mentioned invention is described below in the present invention 1.
That.

The present invention 2 provides a mercaptomethyl group-containing polythiol compound containing no ester bond and having a mercaptoalkyl group having 2 or more carbon atoms as a substituent (hereinafter, referred to as a mercaptomethyl group-containing polythiol compound):
A photocurable resin composition comprising a polyene compound having two or more carbon-carbon double bonds in one molecule and a photopolymerization initiator.

Examples of the above-mentioned mercaptomethyl group-containing polythiol compound include 2,5-bis (dimercaptoethylthiomethyl) -1,4-dithiane and 2,5-bis (dimercaptopropylthiomethyl) -1,4 -Dithiane, 2,5-bis (dimercaptobutylthiomethyl)-
1,4-dithiane and the like can be mentioned.

The mixing ratio of the above-mentioned mercaptomethyl group-containing polythiol compound and the above-mentioned polyene compound having two or more carbon-carbon double bonds in one molecule is not particularly limited. It is preferable to blend the polyene compound having two or more carbon-carbon double bonds in one molecule such that the molar ratio to the carbon-carbon double bond is 5: 1 to 1: 5. A more preferred molar ratio is around 1: 1. By using the above mercaptomethyl group-containing polythiol compound,
Liquid crystal contamination can be further reduced.

The photopolymerization initiator is added in an amount of 0 parts by weight based on 100 parts by weight of the total amount of the mercaptomethyl group-containing polythiol compound and the polyene compound having two or more carbon-carbon double bonds in one molecule. The range is preferably 0.0001 to 10 parts by weight, more preferably 0.05 to 5 parts by weight.

The photocurable resin compositions of the present invention 1 and 2 (hereinafter simply referred to as photocurable resin compositions) include a polythiol compound containing no ester bond or a polythiol compound containing a mercaptomethyl group, In addition to a polyene compound having two or more carbon-carbon double bonds in one molecule and a photopolymerization initiator, if necessary, an adhesion improver such as an organosilicon compound, an antioxidant, a polymerization inhibitor,
Various commonly used additives such as a filler, a colorant, a thixotropic agent, a curing accelerator, a plasticizer, and a surfactant may be blended.

The photocurable resin composition having the above composition does not soften even under high temperature and high humidity, has a high adhesive strength, and has a low moisture permeability. Therefore, it is suitably used as a sealing agent for a liquid crystal injection port. In order to use the photocurable resin composition as a sealing agent for a liquid crystal injection port, first, two transparent plates with a transparent electrode such as an ITO thin film are opposed to each other at an interval via an appropriate spacer, The periphery of the cell is sealed with a suitable sealing body leaving a liquid crystal injection port to form a cell.

The seal is not particularly limited, and examples thereof include an epoxy resin and a polyimide resin.
Next, after injecting liquid crystal into the cell from the liquid crystal injection port, the liquid crystal injection port is closed with a liquid crystal injection port sealing agent, and this is irradiated with an actinic ray to cure the sealing agent. By using the above method, the liquid crystal injection port can be sealed.

The liquid crystal is not particularly limited.
A liquid crystal can be used, and examples thereof include a nematic liquid crystal, a cholesteric liquid crystal, and a smectic liquid crystal.

The above-mentioned actinic rays include, for example, ultraviolet rays using an ultra-high pressure mercury lamp, a high pressure mercury lamp, a low pressure mercury lamp, a metal halide lamp or the like as a light source. The above liquid crystal inlet sealing agent is also one of the present invention.

By irradiating the above-mentioned actinic ray, the liquid crystal injection port sealing agent using the photocurable resin composition of the present invention can be treated in the same manner as the conventional polyene / polythiol-based photocurable resin composition.
It cures in a short time of several seconds to several minutes, and can seal the liquid crystal injection port. Through the above steps, a liquid crystal display cell is manufactured. The above liquid crystal display cell is also one of the present invention.

[0030]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.

Example 1 44 parts by weight of triallylisocyanurate and 56 parts by weight of 2,5-dimercaptomethyl-1,4-dithiane were mixed and heated to increase the viscosity to 18,000 cps. Thereafter, 2.3 parts by weight of benzoin isopropyl ether was added thereto to obtain a photocurable resin composition. Physical properties of the obtained photocurable resin composition were evaluated, and the results are shown in Table 1.

[0032]Evaluation method  (1) Hardness (D) Hardness after leaving in an atmosphere of 85 ° C and 85% relative humidity
Was measured at regular intervals. (2) Adhesive strength (kg / cm^Two First, photocuring obtained on a 20 × 60 × 8 mm glass plate
About 1 mg of the conductive resin composition is applied, and the other glass plate is
3000mj / cm after stacking on a cross^Two UV intensity
And irradiated and bonded. This was subjected to a plane tensile test (pull
(Stretching speed: 5 mm / min) and measure the adhesive strength
did.

(3) Moisture Permeability (gr / m ² ) The obtained photocurable resin composition is applied to a polyethylene terephthalate (PET) film, and then cured by irradiating ultraviolet rays to form a film having a thickness of 1 mm. Was prepared. Using the prepared film, the moisture permeability was measured according to the method of JIS Z0208. (4) Liquid crystal specific resistance (Ω-cm) 2 gr of liquid crystal (JC-5004LA manufactured by Chisso Corporation) and 0.25 gr of the obtained photocurable resin composition were placed in a sample tube and heated at 100 ° C. for 2 hours. Was measured with a hyper-insulation meter.

(5) Voltage holding ratio Two 50 × 50 mm glass plates coated with an alignment film (AL-3046, manufactured by Nippon Synthetic Rubber Co., Ltd.) are bonded to form a cell, and a liquid crystal (JC, manufactured by Chisso Corporation) is formed therein. -5004L
After charging A) and sealing the injection port with the obtained photocurable resin composition, the cell was measured for voltage holding ratio under the following conditions. Applied voltage: ± 5 V Frequency: 60 Hz, 2 Hz Frame frequency: 16.7 ms, 500 ms Pulse width: 0.835 ms, 25 ms (6) Sink (void) The obtained photocurable resin composition is actually used for liquid crystal cell injection. After sealing the inlet, the sealed portion was sandwiched between polarizing plates, and the state of void generation was observed with a microscope. The rate of occurrence of voids is shown in%.

Example 2 10 parts by weight of triallylisocyanurate and 100 parts by weight of 2,5-dimercaptomethyl-1,4-dithiane were mixed and heated to react until the double bond disappeared. Was removed by distillation to obtain a polythiol oligomer. Further, 77 parts by weight of the obtained polythiol oligomer, 23 parts by weight of triallyl isocyanurate and 2.3 parts by weight of benzoin isopropyl ether were blended to obtain a photocurable resin composition.
The physical properties of the obtained photocurable resin composition were evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 3 33 parts by weight of triallylisocyanurate and 2,5-bis (dimercaptoethylthiomethyl) -1,2-mercaptoethyl-substituted 2,5-dimercaptomethyl-1,4-dithiane 67 parts by weight of 4-dithiane were mixed and heated to increase the viscosity to 18000 cps. Thereafter, 2.3 parts by weight of benzoin isopropyl ether was added thereto to obtain a photocurable resin composition. The physical properties of the obtained photocurable resin composition were evaluated in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 1 The procedure of Example 1 was repeated, except that 70 parts by weight of trimethylolpropanetris-β-mercaptopropionate was used instead of 2,5-dimercaptomethyl-1,4-dithiane. A curable resin composition was obtained. The physical properties of the obtained photocurable resin composition were evaluated in the same manner as in Example 1, and the results are shown in Table 1.

Comparative Example 2 A photocurable resin composition was obtained in the same manner as in Comparative Example 1, except that the raw materials were purified and a urethane compound was further blended.
The physical properties of the obtained photocurable resin composition were evaluated in the same manner as in Comparative Example 1, and the results are shown in Table 1.

[0039]

[Table 1]

[0040]

Since the photocurable resin composition of the present invention has the above-mentioned constitution, it does not soften even under high temperature and high humidity, has a high adhesive strength, has low moisture permeability, and further has a liquid crystal injection port sealing agent. When used, no voids are generated at the liquid crystal injection port, and there is no contamination of the liquid crystal.

Claims (8)

[Claims] 1. A photocurable resin comprising a polythiol compound containing no ester bond, a polyene compound having two or more carbon-carbon double bonds in one molecule, and a photopolymerization initiator. Composition. 2. The photocurable resin composition according to claim 1, wherein the polythiol compound containing no ester bond is a polyene-added polythiol compound. 3. The photocurable resin composition according to claim 2, wherein the polyene-added polythiol compound is a compound of a cyclic sulfide compound and triallyl isocyanurate or triallyl cyanurate. 4. A mercaptomethyl group-containing polythiol compound containing no ester bond and having a mercaptoalkyl group having 2 or more carbon atoms as a substituent, and a polyene compound having 2 or more carbon-carbon double bonds in one molecule. And a photopolymerization initiator. 5. The photocurable resin composition according to claim 1, wherein the polythiol compound is a cyclic sulfide compound. 6. The photocurable resin composition according to claim 5, wherein the polythiol compound is a 1,4-dithiane ring-containing polythiol compound having two or more thiol groups in one molecule. 7. A liquid crystal injection port sealing agent comprising the photocurable resin composition according to claim 1. Description: 8. A liquid crystal injection port of a cell into which liquid crystal has been injected,
A liquid crystal display cell, which is sealed with the liquid crystal injection port sealing agent according to claim 7.