A sealant for liquid crystal encapsulation and its preparation method

Abstract

The present invention discloses a sealant for liquid crystal encapsulation and a preparation method thereof, which relates to the field of photoinitiators. The key technical points of the technical solution are as follows: It includes a curable resin, a thermal curing agent, a free radical polymerization inhibitor, a silane coupling agent, a filler, and a macromolecular photoinitiator B. Because it contains the macromolecular photoinitiator B, due to its large molecular weight and large volume, it has the characteristic of slow migration speed and is not easy to contaminate liquid crystal.

Description

Technical Field

[0001] The present invention relates to the field of photoinitiators, and more specifically, to a sealant for liquid crystal encapsulation with low liquid crystal contamination and a preparation method thereof. Background Art

[0002] In recent years, liquid crystal display units have been applied to large display screens such as televisions. They are versatile and in increasing demand. Therefore, for liquid crystal panel manufacturing, in order to improve mass production, the ODF (One Drop Fill) method (also known as the liquid crystal dropping method, etc.) has replaced the liquid crystal injection method as the mainstream. In the dropping process, first, a rectangular sealing pattern is formed by dispensing on one of two transparent substrates with electrodes. Then, with the sealant in an uncured state, tiny liquid crystal drops are dropped into the entire frame of the transparent substrate, and immediately another transparent substrate is overlapped. Ultraviolet light or the like is irradiated on the sealed portion for temporary curing. Thereafter, main curing is performed by heating during liquid crystal annealing to fabricate a liquid crystal display element.

[0003] However, in recent years, due to the need for narrow bezels, the sealing position tends to be closer to the display pixels. Therefore, due to contamination from the sealant, there is a tendency to affect the electrical characteristics of the display pixel portion and easily cause display defects. Especially in small panels, the distance from the display portion to the sealant is narrow, and the occurrence of display defects due to contamination is more obvious. Thus, a sealant with less liquid crystal contamination is required.

[0004] Chinese Patent with Publication No. CN105900003B, a sealant for liquid crystal dropping process, an upper and lower conduction material, and a liquid crystal display element. However, due to the narrow bezel design of the panel in recent years, the sealant is very close to the display area. When using a sealant based on epoxy (meth)acrylate with more than 3 functional groups, in the dropping process, the sealant easily dissolves into the liquid crystal when it comes into contact with the liquid crystal, causing contamination. Also, in the existing ODF process, the liquid crystal sealant contacts the liquid crystal in an uncured state. Therefore, the components of the sealant are likely to dissolve out, resulting in problems such as liquid crystal contamination. Among the sealant components, the photoinitiator component is particularly prominent in contaminating the liquid crystal because small molecule photoinitiators are commonly used in conventional sealants. After ultraviolet curing, the remaining small molecule photoinitiators or photolysis products migrate to the coating surface due to their fast migration speed and then dissolve into the liquid crystal, causing contamination. Summary of the Invention

[0005] The object of the present invention is to provide a sealant for liquid crystal encapsulation and a preparation method thereof. Because it contains a macromolecular photoinitiator B, due to its large molecular weight and large volume, it has the characteristic of slow migration speed and is not likely to contaminate the liquid crystal. In addition, because the resin macromolecular photoinitiator compound has a large polarity and poor compatibility with the liquid crystal, even when it comes into contact with the liquid crystal in the liquid crystal dropping process, it does not contaminate the liquid crystal.

[0006] The above technical object of the present invention is achieved by the following technical solutions: A sealant for liquid crystal encapsulation, comprising a curable resin, a thermal curing agent, a free radical polymerization inhibitor, a silane coupling agent, a filler, and a macromolecular photoinitiator B, and the structural formula of the macromolecular photoinitiator B is as follows:

[0007]

[0008] Y represents H or CH3;

[0009] m and n represent integers from 0 to 2;

[0010] R1 represents CH2, (CH3)2C, (CH3)CH, O, S, SO2;

[0011] R2: represents a part derived from a polybasic acid or a cyclic anhydride, and represents a fatty chain or an aromatic compound structure with 1 to 20 carbons;

[0012] R3: represents H, CH3, benzyl, phenethyl, phenylpropyl;

[0013] R4: represents CH3, CH3CH2,

[0014] Preferably, the curable resin comprises one or a mixture of two of epoxy resin, (meth)acrylic acid modified resin, and partially methacrylic acid modified bisphenol A epoxy resin.

[0015] Preferably, the curable resin accounts for 30-90 parts by weight of the sealant composition, the resin-type macromolecular photoinitiator accounts for 0.1-15 parts by weight, the free radical polymerization inhibitor accounts for 0.1-5 parts by weight, the thermal curing agent accounts for 1-40 parts by weight, the filler accounts for 5-60 parts by weight, and the silane coupling agent accounts for 0.1-15 parts by weight.

[0016] Preferably, the free radical polymerization inhibitor includes one or a mixture of 2,6-di-tert-butylcresol, butylated hydroxyanisole, 2,6-di-tert-butyl-4-ethylphenol, stearoyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, 2,2'-methylenebis(4-methyl-6-tert-butylphenol), 2,2'-methylenebis(4-ethyl-6-tert-butylphenol), 4,4'-thiobis-3-methyl-6-tert-butylphenol), 4,4-butylidenebis(3-methyl-6-tert-butylphenol), hydroquinone, p-methoxyphenol.

[0017] Preferably, the thermal curing agent includes one or several of organic acid hydrazide, imidazole derivative, amine compound, polyhydric phenol compound, acid anhydride.

[0018] Preferably, the filler includes one or a mixture of more than one of talc, asbestos, silica, diatomaceous earth, smectite, bentonite, calcium carbonate, magnesium carbonate, alumina, montmorillonite, zinc oxide, iron oxide, magnesium oxide, tin oxide, titanium oxide, magnesium hydroxide, aluminum hydroxide, glass beads, silicon nitride, barium sulfate, gypsum, calcium silicate, sericite, activated clay, aluminum nitride, polyester particles, polyurethane particles, vinyl polymer particles, and acrylic polymer particles.

[0019] Preferably, the silane coupling agent includes one or a mixture of more than one of 3-aminopropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, and 3-isocyanatopropyltrimethoxysilane.

[0020] Preferably, the sealant further contains a UV photo radical polymerization initiator, and the UV photo radical polymerization initiator includes one or a mixture of several of benzophenone compounds, acetophenone compounds, acylphosphine oxide compounds, titanocene compounds, oxime ester compounds, benzoin ether compounds, and thioxanthone compounds.

[0021] Another object of the present invention is to provide a method for preparing a sealant for liquid crystal encapsulation, including the following steps:

[0022] First step: After the hydroxy ketone compound reacts with a polybasic acid or a cyclic anhydride, a compound A is formed. The compound A reacts with a compound having at least two epoxy groups to form a compound B. The structure of the compound A is shown as follows:

[0023]

[0024] R2: represents a part derived from a polybasic acid or a cyclic anhydride, which is represented as an aliphatic chain or an aromatic compound structure with 1 to 20 carbons;

[0025] R3: represents H, CH3, benzyl, phenethyl, phenylpropyl;

[0026] R4: represents CH3, CH3CH2,

[0027] Second step: Using a planetary mixer, the (meth)acrylic acid modified resin, a part of the methacrylic acid modified bisphenol A epoxy resin, and the macromolecular resin photoinitiator B are premixed, and then a thermal curing agent, a filler, a silane coupling agent, and a radical polymerization inhibitor are added and mixed again;

[0028] Third step: Grind and mix with a three-roll mill to prepare a sealant for liquid crystal encapsulation.

[0029] In summary, the beneficial effects achieved by the present invention are as follows: First, because it contains the macromolecular resin photoinitiator B, due to its large molecular weight and large volume, it has the characteristic of slow migration speed and is not easily contaminated with liquid crystal.

[0030] Second, in addition, because the macromolecular photoinitiator B compound has a large polarity and poor compatibility with liquid crystal, even if it comes into contact with liquid crystal in the liquid crystal dripping process, it will not contaminate the liquid crystal.

[0031] Third, in addition, the cleavage product of the macromolecular photoinitiator B itself is a part of the curable resin, and it will cooperate with the curable resin to cure together, hardly causing pollution to the liquid crystal. Secondly, the cleavage product is also a resin component and has a similar structure to the main resin, showing good mutual solubility and also showing more excellent adhesive properties during use. Specific Embodiments

[0032] The following are examples listed to illustrate the present invention in more detail, but the present invention is not limited to these examples.

[0033] A method for preparing a sealant for liquid crystal encapsulation, comprising the following steps:

[0034] First step: A hydroxyketone compound reacts with a polybasic acid or cyclic anhydride to form compound A, and compound A reacts with a compound having at least two epoxy groups to form compound B. The structure of compound A is as follows:

[0035]

[0036] R2: represents a part derived from a polybasic acid or cyclic anhydride, which is represented as an aliphatic chain or aromatic compound structure having 1 to 20 carbons;

[0037] R3: represents H, CH3, benzyl, phenethyl, phenylpropyl;

[0038] R4: represents CH3, CH3CH2,

[0039] Second step: Use a planetary mixer to premix the curable resin and the macromolecular resin photoinitiator B, and then add a thermal curing agent, a filler, a silane coupling agent, and a radical polymerization inhibitor and mix again;

[0040] Third step: Grind and mix with a three-roll mill to prepare a sealant for liquid crystal encapsulation.

[0041] Examples of commercially available products of the above-mentioned hydroxy ketone compounds include photoinitiator 1173, photoinitiator 184, photoinitiator 2959, benzoin, and preferably photoinitiator 184; examples of the above-mentioned polybasic acid compounds include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, and preferably glutaric acid and adipic acid; examples of the above-mentioned cyclic acid anhydrides include maleic anhydride, succinic anhydride, glutaric anhydride, adipic anhydride, 1,2-cyclohexanedicarboxylic anhydride, phthalic anhydride, and preferably succinic anhydride and phthalic anhydride.

[0042] Examples of the epoxy resin having at least two epoxy groups include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, 2,2'-diallylbisphenol A type epoxy resin, hydrogenated bisphenol A type epoxy resin, epoxy propane adduct bisphenol A type epoxy resin, resorcinol type epoxy resin, biphenyl type epoxy resin, thioether type epoxy resin, diphenyl ether epoxy resin, dicyclopentadiene type epoxy resin, naphthalene type epoxy resin, phenol novolac type epoxy resin, naphthol novolac type epoxy resin, glycidylamine type epoxy resin, alkyl polyol type epoxy resin, rubber-modified epoxy resin, glycidyl ester compound, etc., and preferably bisphenol A type epoxy resin.

[0043] The curable resin contains one or a mixture of two of epoxy resin, (meth)acrylic acid-modified resin, and partially methacrylic acid-modified bisphenol A type epoxy resin; for the above-mentioned curable epoxy resin, known resins can be used, for example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AD type epoxy resin, linear phenolic type epoxy resin, cresol novolac epoxy resin, cycloaliphatic epoxy resin, glycidyl ester resin, glycidylamine epoxy resin, heterocyclic epoxy resin, urethane-modified epoxy resin, etc. can be cited; the above-mentioned (meth)acrylic acid-modified resin is obtained by reacting (meth)acrylic acid with an epoxide compound, and there is no particular limitation. For example, a compound obtained by reacting epoxy resin and (meth)acrylic acid by a conventional method in the presence of a basic catalyst can be cited.

[0044] There is no particular limitation on the epoxy resin used for synthesizing the resin photoinitiator and the (meth)acrylic acid-modified resin. As commercially available products, for example, bisphenol A type epoxy resins such as YD-128 (Kukdo Chemical), NPEL-128 (Nan Ya), EPICLON 850 (DIC), jER828EL (manufactured by Mitsubishi Chemical Corporation); bisphenol F type epoxy resins such as EPICOAT806, EPICOAT4004 (both manufactured by Japan Epoxy Resin Co., Ltd.); bisphenol S type epoxy resins such as EPICLON EXA1514 (manufactured by DIC Corporation); 2,2'-diallylbisphenol A type epoxy resins such as RE-810NM (manufactured by Nippon Kayaku Co., Ltd.); hydrogenated bisphenol type epoxy resins such as EPICLON EXA7015 (manufactured by DIC Corporation); epoxy propane adduct bisphenol A type epoxy resins such as EP-4000S (manufactured by ADEKA Corporation); resorcinol type epoxy resins such as EX-201 (manufactured by Nagase Chemtex Corporation); biphenyl type epoxy resins such as EPICOAT YX-4000H (manufactured by Japan Epoxy Resin Co., Ltd.); sulfide type epoxy resins such as YSLV-50TE (manufactured by Tohto Kasei Co., Ltd.); ether type epoxy resins such as YSLV-8ODE (manufactured by Tohto Kasei Co., Ltd.); dicyclopentadiene type epoxy resins such as EP-4088S (manufactured by ADEKA Corporation); naphthalene type epoxy resins such as EPICLONHP4032, EPICLON EXA-4700 (both manufactured by DIC Corporation); phenol novolac type epoxy resins such as EPICLON N-770 (manufactured by DIC Corporation); o-cresol novolac type epoxy resins such as EPICLON N-670-EXP-S (manufactured by DIC Corporation); dicyclopentadiene novolac type epoxy resins such as EPICLON HP7200 (manufactured by DIC Corporation); biphenyl novolac type epoxy resins such as NC-3000P (manufactured by Nippon Kayaku Co., Ltd.); naphthol novolac type epoxy resins such as ESN-165S (manufactured by Tohto Kasei Co., Ltd.), glycidylamine type epoxy resins such as EPICOAT 630 (manufactured by Japan Epoxy Resin Co., Ltd.), EPICLON 430 (manufactured by DIC Corporation), TETRAD-X (manufactured by Mitsubishi Gas Chemical Company); alkyl polyol type epoxy resins such as ZX-1542 (manufactured by Tohto Kasei Co., Ltd.), EPICLON 726 (manufactured by DIC Corporation), EPOLIGHT80MFA (manufactured by Kyoeisha Chemical Co., Ltd.), DENACOL EX-611 (manufactured by NagaseChemtex Corporation); glycidyl ester compounds such as DENACOLEX-147 (manufactured by Nagase Chemtex Corporation).

[0045] In addition, as commercially available products of the above-mentioned (meth)acrylic acid-modified resin, for example, the following can be cited: EBECRYL 3700, EBECRYL 3600, EBECRYL 3701, EBECRYL 3703, EBECRYL-3200, EBECRYL 3201, EBECRYL 3600, EBECRYL 3702, EBECRYLL 3412, EBECRYL 860, EBECRYL RDX 63182, EBECRYL 6040, EBECRYL 3800 (all manufactured by Daicel cytec Co., Ltd.), EA-1020, EA-1010, EA-5520, EA-5323, EA-CHD, EMA-1020 (all manufactured by Shin-Nakamura Chemical Co., Ltd.), epoxy ester M-600A, epoxy ester 40EM, epoxy ester 7OPA, epoxy ester 20OPA, epoxy ester 8OMFA, epoxy ester 3002M, epoxy ester 3002A, epoxy ester 1600A, epoxy ester 3000M, epoxy ester 3000A, epoxy ester 20OEA, epoxy ester 40OEA (all manufactured by Kyoeisha Chemical Co., Ltd.), DENACOL acrylate DA-141, DENACOL acrylate DA-314, DENACOL acrylate DA-911 (all manufactured by Nagase Chemtex Corporation), etc.

[0046] As commercially available products of the above-mentioned photo radical polymerization initiator, for example, the following can be cited: IRGACURE 184, IRGACURE 369, IRGACURE 379, IRGACURE 651, IRGACURE 819, IRGACURE 907, IRGACURE 2959, IRGACURE OXEO1, Lucirin TPO (all manufactured by BASF Corporation); NCI-930 (manufactured by ADEKA Corporation); SPEEDCURE EMK (manufactured by Japan Siber Hegner Co., Ltd.), benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether (all manufactured by Tokyo Chemical Industry Co., Ltd.), etc.

[0047] The macromolecular resin photo radical polymerization initiators B1 to 8 in the above first step are prepared as follows:

[0048] (Synthesis of macromolecular resin photo radical polymerization initiator B1-1)

[0049] Add 10 g of succinic anhydride, 19.9 g of photoinitiator 184, and 100 ml of DMF (N,N-dimethylformamide) into a 250-ml three-necked flask. Heat the mixture to 120 °C under stirring and nitrogen protection for reaction. After the acid value remains constant, treat it to obtain A1-1. While stirring, add A1-1 dropwise to a three-necked flask containing 60.03 g of bisphenol A epoxy resin within 2 h. React until the acid value remains constant, and treat it to obtain 50.2 g of compound B1-1 with a yield of 80%.

[0050]

[0051] (Synthesis of macromolecular resin photoinitiator B1-2)

[0052] Add 12.55 g of succinic anhydride, 20 g of photoinitiator 1173, and 100 ml of DMF (N,N-dimethylformamide) into a 250-ml three-necked flask. Heat the mixture to 120 °C under stirring and nitrogen protection for reaction. After the acid value remains constant, treat it to obtain A1-2. While stirring, add A1-2 dropwise to a three-necked flask containing 74.63 g of bisphenol A epoxy resin within 2 h. React until the acid value remains constant, and treat it to obtain 62.6 g of compound B1-2 with a yield of 85%.

[0053]

[0054]

[0055] (Synthesis of macromolecular resin photoinitiator B1-3)

[0056] Add 9.19 g of succinic anhydride, 20 g of photoinitiator 2959, and 100 ml of DMF (N,N-dimethylformamide) into a 250-ml three-necked flask. Heat the mixture to 120 °C under stirring and nitrogen protection for reaction. After the acid value remains constant, treat it to obtain A1-3. While stirring, add A1-3 dropwise to a three-necked flask containing 54.65 g of bisphenol A epoxy resin within 2 h. React until the acid value remains constant, and treat it to obtain 50.38 g of compound B1-1 with a yield of 85%.

[0057]

[0058] (Synthesis of macromolecular resin photoinitiator B1-4)

[0059] Add 9.71 g of succinic anhydride, 20 g of benzoin, and 100 ml of DMF (N,N-dimethylformamide) into a 250 ml three-necked flask. Under stirring and nitrogen protection, heat the mixture to 120 °C for reaction. After the acid value remains constant, treat to obtain A1-4. Under stirring, add A1-4 dropwise to a three-necked flask containing 57.74 g of bisphenol A epoxy resin within 2 h. After the reaction until the acid value remains constant, treat to obtain 49.208 g of compound B1-4, with a yield of 80%.

[0060]

[0061] (Synthesis of macromolecular resin photoinitiator B1-5)

[0062] Add 14.94 g of phthalic anhydride, 20 g of photoinitiator 184, and 100 ml of DMF (N,N-dimethylformamide) into a 250 ml three-necked flask. Under stirring and nitrogen protection, heat the mixture to 120 °C for reaction. After the acid value remains constant, treat to obtain A1-5. Under stirring, add A1-5 dropwise to a three-necked flask containing 59.99 g of bisphenol A epoxy resin within 2 h. After the reaction until the acid value remains constant, treat to obtain 54.264 g of compound B1-5, with a yield of 80%.

[0063]

[0064] (Synthesis of macromolecular resin photoinitiator B1-6)

[0065] Add 18.58 g of phthalic anhydride, 20 g of photoinitiator 1173, and 100 ml of DMF (N,N-dimethylformamide) into a 250 ml three-necked flask. Under stirring and nitrogen protection, heat the mixture to 120 °C for reaction. After the acid value remains constant, treat to obtain A1-6. Under stirring, add A1-6 dropwise to a three-necked flask containing 74.63 g of bisphenol A epoxy resin within 2 h. After the reaction until the acid value remains constant, treat to obtain 63.6 g of compound B1-6, with a yield of 80%.

[0066]

[0067] (Synthesis of macromolecular resin photoinitiator B1-7)

[0068] Add 13.61 g of phthalic anhydride, 20 g of photoinitiator 2959, and 100 ml of DMF (N,N-dimethylformamide) into a 250 ml three-necked flask. Under stirring and nitrogen protection, heat the mixture to 120 °C for reaction. After the acid value remains constant, treat to obtain A1-7. Under stirring, add A1-7 dropwise to a three-necked flask containing 54.65 g of bisphenol A epoxy resin within 2 h. After the reaction until the acid value remains constant, treat to obtain 50.856 g of compound B1-7, with a yield of 80%.

[0069]

[0070] (Synthesis of Macromolecular Resin Photoinitiator B1-8)

[0071] Add 14.38 g of phthalic anhydride, 20 g of benzoin, and 100 ml of DMF (N,N-dimethylformamide) into a 250 ml three-necked flask. Heat the mixture to 120 °C under stirring and nitrogen protection for reaction. After the acid value is constant, treat to obtain A1-8. Dropwise add A1-8 into a three-necked flask containing 57.74 g of bisphenol A epoxy resin within 2 h under stirring. React until the acid value is constant, and treat to obtain 52.824 g of compound B1-8 with a yield of 80%.

[0072]

[0073]

[0074] (Example 1)

[0075] Pre-mix 70 parts by weight of bisphenol A epoxy resin (Nanya "NPEL-128"), 20 parts by weight of (meth)acrylic acid modified resin ("EBECRYL3700" manufactured by DIC Corporation), 10 parts by weight of partially methacrylic acid modified bisphenol A epoxy resin ("UVAC1561"), and 2 parts by weight of compound B1-1 using a planetary mixer. Then add 15 parts by weight of heat curing agent UDH-J, 15 parts by weight of organic filler F351 (manufactured by ZEON Chemicals), 15 parts by weight of silica, 2.5 parts by weight of 3-glycidoxypropyltrimethoxysilane, and 1 part by weight of 2,6-di-tert-butyl-p-cresol and mix again. Finally, grind and mix using a three-roll mill to prepare the sealant for liquid crystal encapsulation of Example 1.

[0076] (Example 2)

[0077] Pre-mix 70 parts by weight of bisphenol A epoxy resin (Nanya "NPEL-128"), 20 parts by weight of (meth)acrylic acid modified resin ("EBECRYL3700" manufactured by DIC Corporation), 10 parts by weight of partially methacrylic acid modified bisphenol A epoxy resin ("UVAC1561"), and 2 parts by weight of compound B1-2 using a planetary mixer. Then add 15 parts by weight of heat curing agent UDH-J, 15 parts by weight of organic filler F351 (manufactured by ZEON Chemicals), 15 parts by weight of silica, 2.5 parts by weight of 3-glycidoxypropyltrimethoxysilane, and 1 part by weight of 2,6-di-tert-butyl-p-cresol and mix again. Finally, grind and mix using a three-roll mill to prepare the sealant for liquid crystal encapsulation of Example 2.

[0078] (Example 3)

[0079] Using a planetary mixer, 70 parts by weight of bisphenol A epoxy resin (Nanya "NPEL-128"), 20 parts by weight of (meth)acrylic acid modified resin ("EBECRYL3700" manufactured by DIC Corporation), 10 parts by weight of partially methacrylic acid modified bisphenol A epoxy resin ("UVAC1561"), and 2 parts by weight of Compound B1-3 were premixed. Then, 15 parts by weight of heat curing agent UDH-J, 15 parts by weight of organic filler F351 (manufactured by ZEON Chemicals), 15 parts by weight of silica, 2.5 parts by weight of 3-glycidoxypropyltrimethoxysilane, and 1 part by weight of 2,6-di-tert-butyl-p-cresol were added and mixed again. Finally, it was ground and mixed using a three-roll mill to prepare the sealant for liquid crystal encapsulation of Example 3.

[0080] (Example 4)

[0081] Using a planetary mixer, 70 parts by weight of bisphenol A epoxy resin (Nanya "NPEL-128"), 20 parts by weight of (meth)acrylic acid modified resin ("EBECRYL3700" manufactured by DIC Corporation), 10 parts by weight of partially methacrylic acid modified bisphenol A epoxy resin ("UVAC1561"), and 2 parts by weight of Compound B1-4 were premixed. Then, 15 parts by weight of heat curing agent UDH-J, 15 parts by weight of organic filler F351 (manufactured by ZEON Chemicals), 15 parts by weight of silica, 2.5 parts by weight of 3-glycidoxypropyltrimethoxysilane, and 1 part by weight of 2,6-di-tert-butyl-p-cresol were added and mixed again. Finally, it was ground and mixed using a three-roll mill to prepare the sealant for liquid crystal encapsulation of Example 4.

[0082] (Example 5)

[0083] Using a planetary mixer, 70 parts by weight of bisphenol A epoxy resin (Nanya "NPEL-128"), 20 parts by weight of (meth)acrylic acid modified resin ("EBECRYL3700" manufactured by DIC Corporation), 10 parts by weight of partially methacrylic acid modified bisphenol A epoxy resin ("UVAC1561"), and 2 parts by weight of Compound B1-5 were premixed. Then, 15 parts by weight of heat curing agent UDH-J, 15 parts by weight of organic filler F351 (manufactured by ZEON Chemicals), 15 parts by weight of silica, 2.5 parts by weight of 3-glycidoxypropyltrimethoxysilane, and 1 part by weight of 2,6-di-tert-butyl-p-cresol were added and mixed again. Finally, it was ground and mixed using a three-roll mill to prepare the sealant for liquid crystal encapsulation of Example 5.

[0084] (Example 6)

[0085] Using a planetary mixer, 70 parts by weight of bisphenol A epoxy resin (Nanya "NPEL-128"), 20 parts by weight of (meth)acrylic acid modified resin ("EBECRYL3700" manufactured by DIC Corporation), 10 parts by weight of partially methacrylic acid modified bisphenol A epoxy resin ("UVAC1561"), and 2 parts by weight of Compound B1-6 were premixed. Then, 15 parts by weight of heat curing agent UDH-J, 15 parts by weight of organic filler F351 (manufactured by ZEON Chemicals), 15 parts by weight of silica, 2.5 parts by weight of 3-glycidoxypropyltrimethoxysilane, and 1 part by weight of 2,6-di-tert-butyl-p-cresol were added and mixed again. Finally, it was ground and mixed using a three-roll mill to prepare the sealant for liquid crystal encapsulation of Example 6.

[0086] (Example 7)

[0087] Using a planetary mixer, 70 parts by weight of bisphenol A epoxy resin (Nanya "NPEL-128"), 20 parts by weight of (meth)acrylic acid modified resin ("EBECRYL3700" manufactured by DIC Corporation), 10 parts by weight of partially methacrylic acid modified bisphenol A epoxy resin ("UVAC1561"), and 2 parts by weight of Compound B1-7 were premixed. Then, 15 parts by weight of heat curing agent UDH-J, 15 parts by weight of organic filler F351 (manufactured by ZEON Chemicals), 15 parts by weight of silica, 2.5 parts by weight of 3-glycidoxypropyltrimethoxysilane, and 1 part by weight of 2,6-di-tert-butyl-p-cresol were added and mixed again. Finally, it was ground and mixed using a three-roll mill to prepare the sealant for liquid crystal encapsulation of Example 7.

[0088] (Example 8)

[0089] Using a planetary mixer, 70 parts by weight of bisphenol A epoxy resin (Nanya "NPEL-128"), 20 parts by weight of (meth)acrylic acid modified resin ("EBECRYL3700" manufactured by DIC Corporation), 10 parts by weight of partially methacrylic acid modified bisphenol A epoxy resin ("UVAC1561"), and 2 parts by weight of Compound B1-8 were premixed. Then, 15 parts by weight of heat curing agent UDH-J, 15 parts by weight of organic filler F351 (manufactured by ZEON Chemicals), 15 parts by weight of silica, 2.5 parts by weight of 3-glycidoxypropyltrimethoxysilane, and 1 part by weight of 2,6-di-tert-butyl-p-cresol were added and mixed again. Finally, it was ground and mixed using a three-roll mill to prepare the sealant for liquid crystal encapsulation of Example 8.

[0090] (Comparative Example 1)

[0091] Using a planetary mixer, 70 parts by weight of bisphenol A epoxy resin (Nanya "NPEL-128"), 20 parts by weight of (meth)acrylic acid-modified resin ("EBECRYL3700" manufactured by DIC Corporation), 10 parts by weight of partially methacrylic acid-modified bisphenol A epoxy resin ("UVAC1561"), and 2 parts by weight of photoinitiator 184 were premixed. Then, 15 parts by weight of heat curing agent UDH-J, 15 parts by weight of organic filler F351 (manufactured by ZEON Chemicals), 15 parts by weight of silica, 2.5 parts by weight of 3-glycidoxypropyltrimethoxysilane, and 1 part by weight of 2,6-di-tert-butyl-p-cresol were added and mixed again. Finally, it was ground and mixed using a three-roll mill to prepare the sealant for liquid crystal encapsulation of Comparative Example 1.

[0092] (Comparative Example 2)

[0093] Using a planetary mixer, 70 parts by weight of bisphenol A epoxy resin (Nanya "NPEL-128"), 20 parts by weight of (meth)acrylic acid-modified resin ("EBECRYL3700" manufactured by DIC Corporation), 10 parts by weight of partially methacrylic acid-modified bisphenol A epoxy resin ("UVAC1561"), and 2 parts by weight of photoinitiator 2959 were premixed. Then, 15 parts by weight of heat curing agent UDH-J, 15 parts by weight of organic filler F351 (manufactured by ZEON Chemicals), 15 parts by weight of silica, 2.5 parts by weight of 3-glycidoxypropyltrimethoxysilane, and 1 part by weight of 2,6-di-tert-butyl-p-cresol were added and mixed again. Finally, it was ground and mixed using a three-roll mill to prepare the sealant for liquid crystal encapsulation of Comparative Example 2.

[0094] (Comparative Example 3)

[0095] Using a planetary mixer, 70 parts by weight of bisphenol A epoxy resin (Nanya "NPEL-128"), 20 parts by weight of (meth)acrylic acid-modified resin ("EBECRYL3700" manufactured by DIC Corporation), 10 parts by weight of partially methacrylic acid-modified bisphenol A epoxy resin ("UVAC1561"), and 2 parts by weight of photoinitiator TPO (2,4,6-trimethylbenzoyl diphenylphosphine oxide) were premixed. Then, 15 parts by weight of heat curing agent UDH-J, 15 parts by weight of organic filler F351 (manufactured by ZEON Chemicals), 15 parts by weight of silica, 2.5 parts by weight of 3-glycidoxypropyltrimethoxysilane, and 1 part by weight of 2,6-di-tert-butyl-p-cresol were added and mixed again. Finally, it was ground and mixed using a three-roll mill to prepare the sealant for liquid crystal encapsulation of Comparative Example 3.

[0096] Evaluation

[0097] The sealants for liquid crystal encapsulation in the examples and comparative examples were evaluated for viscosity stability, (meth)acryloyl reaction rate, liquid crystal contamination, and adhesion as follows. The results are shown in Table 1-1 (viscosity stability).

[0098] For the sealants for liquid crystal encapsulation in the examples and comparative examples, the viscosity change before and after seven days at 25°C was measured using an E-type viscometer (tested at 2.5 rpm). The viscosity stability is expressed as the ratio of the viscosity after seven days (25°C, 2.5 rpm) to the initial viscosity (25°C, 2.5 rpm). A ratio less than 1.1 indicates excellent viscosity stability, a ratio between 1.1 and 1.2 indicates good viscosity stability, and a ratio greater than 1.2 indicates poor viscosity stability.

[0099] ((Meth)acryloyl reaction rate)

[0100] The sealants in the examples and comparative examples were coated on a glass substrate with a thickness of 0.5 mm, and the sealant was irradiated with a UV irradiation device at an illuminance of 100 mW / cm2 for 30 seconds to prepare a sample for curing property testing. The reaction rate of acryloyl was measured using the FT-IR analysis method. The reaction rate of acryloyl was calculated based on the peak area of the acryloyl group in the obtained IR spectrum. For the calculation of the reaction rate, the area of the absorption peak of the benzene ring double bond (near 1500 cm-1) was used as a reference, and the reduction in the area of the absorption peak of the acryloyl group (near 1630 cm-1) was calculated. A reaction rate of acryloyl less than 50% was judged as a poor reaction rate, a reaction rate between 50% and 70% was considered average, and a reaction rate above 70% was excellent.

[0101] (Liquid crystal contamination - Ni point change)

[0102] 0.1 g of the sealants in the above examples and comparative examples was added to a vial, and then 1 g of liquid crystal (TN, SLC13T50L01, manufactured by SLC) was added to the vial. Subsequently, it was placed in an oven at 120°C for 1 hour. After returning to room temperature, the upper liquid crystal part was taken out and filtered through a 0.2 µm filter membrane to prepare a test sample. It was measured using a differential scanning calorimeter (DSC, manufactured by TA Instruments, USA) under the condition of a heating rate of 10°C / min. The change in the Ni (liquid crystal phase transition point) value was compared with the initial liquid crystal. When the Ni decrease value was within 1°C, the contamination evaluation was excellent; when the Ni decrease value was between 1 - 1.5°C, the contamination evaluation was average. When the Ni value decreased by more than 1.5°C, the contamination evaluation was poor.

[0103] (Adhesion)

[0104] The sealants in the examples and comparative examples were dot-coated between two pieces of ITO glass or ITO glass coated with an alignment film, and were extruded and bonded under pressure, keeping the diameter of the adhesive dots at 1.5 mm after bonding. They were irradiated with a UV irradiation device at an illuminance of 100 mW / cm2 for 30 s and heated at 120 °C for 60 min to cure the frame adhesive, obtaining adhesive test pieces. For the obtained adhesive test pieces, the bonding strength was measured using a tensiometer. When the bonding strength was 300 N / cm2 or more, it was designated as "◎"; when the bonding strength was 270 N / cm2 or more and less than 300 N / cm2, it was designated as "O"; when the bonding strength was less than 270 N / cm2, it was designated as "×", and the adhesiveness was evaluated.

[0105]

[0106]

[0107]

[0108] The above are only the preferred embodiments of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions falling within the concept of the present invention belong to the protection scope of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements should also be regarded as within the protection scope of the present invention.

Claims

1. A sealant for liquid crystal encapsulation, characterized in that, It includes a curable resin, a thermal curing agent, a free radical polymerization inhibitor, a silane coupling agent, a filler, and a macromolecular photoinitiator B. The structural formula of the macromolecular photoinitiator B is as follows: Y represents H or CH3; m and n represent integers from 0 to 2; R1 represents CH2, (CH3)2C, (CH3)CH, O, S, SO2; R2: represents a part derived from a polybasic acid or a cyclic anhydride, which represents a fatty chain or an aromatic compound structure with 1 to 20 carbons; R3: represents H, CH3, benzyl, phenethyl, phenylpropyl; R4: represents CH3, CH3CH2, 2. The sealant for liquid crystal encapsulation according to claim 1, characterized in that: The curable resin includes one or a mixture of two of epoxy resin, (meth)acrylic acid modified resin, and partially methacrylic acid modified bisphenol A epoxy resin.

3. The sealant for liquid crystal encapsulation according to claim 1, characterized in that: The curable resin accounts for 30 - 90 parts by weight in the sealant composition, the resin-type macromolecular photopolymerization initiator accounts for 0.1 - 15 parts by weight, the free radical polymerization inhibitor accounts for 0.1 - 5 parts by weight, the thermal curing agent accounts for 1 - 40 parts by weight, the filler accounts for 5 - 60 parts by weight, and the silane coupling agent accounts for 0.1 - 15 parts by weight.

4. The sealant for liquid crystal encapsulation according to claim 1, characterized in that: The free radical polymerization inhibitor includes one or a mixture of several of 2,6 - di-tert-butyl-p-cresol, butylated hydroxyanisole, 2,6 - di-tert-butyl-4-ethylphenol, stearoyl β-(3,5 - di-tert-butyl-4-hydroxyphenyl) propionate, 2,2'-methylenebis(4-methyl-6-tert-butylphenol), 2,2'-methylenebis(4-ethyl-6-tert-butylphenol), 4,4'-thiobis-3-methyl-6-tert-butylphenol), 4,4-butylidenebis(3-methyl-6-tert-butylphenol), hydroquinone, and p-methoxyphenol.

5. The sealant for liquid crystal encapsulation according to claim 1, characterized in that: The thermal curing agent includes one or several of organic acid hydrazide, imidazole derivatives, amine compounds, polyhydric phenol compounds, and acid anhydrides.

6. The sealant for liquid crystal encapsulation according to claim 1, characterized in that: The filler includes one or a mixture of several of talc, asbestos, silica, diatomaceous earth, smectite, bentonite, calcium carbonate, magnesium carbonate, alumina, montmorillonite, zinc oxide, iron oxide, magnesium oxide, tin oxide, titanium oxide, magnesium hydroxide, aluminum hydroxide, glass beads, silicon nitride, barium sulfate, gypsum, calcium silicate, sericite, activated clay, aluminum nitride, polyester microparticles, polyurethane microparticles, vinyl polymer microparticles, and acrylic polymer microparticles.

7. The sealant for liquid crystal encapsulation according to claim 1, characterized in that: The silane coupling agent includes one or a mixture of several of 3-aminopropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, and 3-isocyanatopropyltrimethoxysilane.

8. The sealant for liquid crystal encapsulation according to claim 1, characterized in that: The sealant also contains a UV light free radical polymerization initiator, and the UV light free radical polymerization initiator includes one or a mixture of several of benzophenone compounds, acetophenone compounds, acylphosphine oxide compounds, titanocene compounds, oxime ester compounds, benzoin ether compounds, and thioxanthone compounds.

9. A preparation method for manufacturing the sealant for liquid crystal encapsulation as described in claim 1 above, characterized in that, It includes the following steps: The first step: After the hydroxyketone compound reacts with a polybasic acid or a cyclic anhydride, compound A is formed. Compound A reacts with an epoxy resin having at least two epoxy groups to form compound B. The structure of compound A is as follows: R2: represents a moiety derived from a polybasic acid or cyclic acid anhydride, which is represented as a fatty chain or aromatic compound structure having 1 to 20 carbons; R3: represents H, CH3, benzyl, phenethyl, phenylpropyl; R4: represents CH3, CH3CH2, Step 2: Using a planetary mixer, pre-mix the (meth)acrylic acid modified resin, a part of the methacrylic acid modified bisphenol A epoxy resin, and the macromolecular resin photoinitiator B, and then add a thermal curing agent, a filler, a silane coupling agent, and a free radical polymerization inhibitor and mix again; Step 3: Grind and mix using a three-roll mill to prepare a sealant for liquid crystal encapsulation.

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