Reactive polymer resin plasticizer and liquid crystal encapsulation sealant prepared therefrom

Abstract

The present invention relates to the field of liquid crystal encapsulation technology, and in particular to a reactive polymer resin plasticizer and a liquid crystal encapsulation sealant prepared therefrom, wherein the reactive polymer resin plasticizer has a structure of any one of (a), (b), and (c). The resin plasticizer can be adjusted in formulation to achieve appropriate flexibility according to the required glass transition temperature, thereby enabling the liquid crystal encapsulation sealant to achieve high bonding strength. Furthermore, the reactive polymer resin plasticizer contains an active epoxy group or a carbon-carbon double bond, so that the resin plasticizer can cross-link with the main chain resin to form a network to achieve a high cross-linking density, thereby enabling the liquid crystal encapsulation sealant to obtain excellent moisture permeability.

Description

Technical Field

[0001] The present invention relates to the technical field of liquid crystal packaging, in particular to a reactive polymer resin plasticizer and a liquid crystal packaging sealant prepared therefrom. Background Art

[0002] In recent years, in order to improve production efficiency and quantify the use of liquid crystals, the manufacturing method of liquid crystal panel display elements has gradually changed from the traditional vacuum injection method to the liquid crystal dripping method. The specific process of liquid crystal dripping is as follows: first, a circle of sealant is applied on a transparent substrate with electrodes to form a rectangular sealing pattern. Then, before the sealant cures, a certain amount of liquid crystal is dripped into the sealing frame of the substrate, and the two transparent substrates with electrodes are bonded together under vacuum. After that, the sealant is temporarily cured using UV irradiation, and finally annealing is performed for the main curing. In the liquid crystal dripping process, considering the rapid curing, free radical polymerization reactive compounds with epoxy acrylate compounds as the main agent are currently more commonly used as liquid crystal sealants.

[0003] With the increasing popularity of smartphones and tablets, demand for smaller LCD panels is increasing. To increase display area and enhance aesthetics, narrower bezels are becoming a trend. Consequently, the width and cross-sectional area of ​​sealants are becoming increasingly narrower. This inevitably results in partial or complete application of sealant to the alignment film, resulting in reduced panel bonding strength and decreased moisture permeability during reliability testing.

[0004] CN110168440A discloses a sealant for liquid crystal display elements, comprising a curable resin and a non-reactive polymer resin plasticizer, wherein the resin is a non-functional (meth)acrylic polymer. The plasticizer blended into the sealant can lower the glass transition temperature of the formulation and increase toughness. However, the non-reactive polymer resin plasticizer cannot cross-link with the resin to form a network. While the sealant itself is tougher and less prone to tearing, it is susceptible to peeling or moisture permeation at the interface with the glass substrate or PI coating.

[0005] Therefore, developing a new reactive polymer resin plasticizer and liquid crystal encapsulation sealant has become one of the technical problems that need to be solved urgently in this field. Summary of the Invention

[0006] The object of the present invention is to provide a reactive polymer resin plasticizer and a liquid crystal encapsulation sealant prepared therefrom.

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] A reactive polymer resin plasticizer, characterized in that: its structure is

[0009]

[0010] Any of;

[0011] wherein R1 is a fragment of hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, hydroxybutyl acrylate or hydroxybutyl methacrylate,

[0012] R2 is a fragment of caprolactone, polybutylene adipate, polybutylene terephthalate, polylactic acid or polybutylene succinate,

[0013] R3 is a fragment of hexahydrophthalic acid, benzoic acid, pyromellitic anhydride, phthalic anhydride, methyltetrahydrophthalic anhydride, trimellitic anhydride, tetrabromophthalic anhydride, maleic anhydride, 70# anhydride, 647# anhydride or 308 tung oil anhydride,

[0014] R4 is a fragment of bisphenol A epoxy resin, bisphenol F epoxy resin, resorcinol diglycidyl ether, 1,4-butanediol glycidyl ether and cyclanyl glycidyl ether, alkylene glycidyl ether, butyl glycidyl ether, ethylene glycol diglycidyl ether, phenyl glycidyl ether, polypropylene glycol diglycidyl ether, C12-14 fatty glycidyl ether, benzyl glycidyl ether, 1,6-hexanediol diglycidyl ether, neopentyl glycol diglycidyl ether, trimethylolpropane triglycidyl ether or allyl glycidyl ether.

[0015] It is prepared by the reaction of vinyl resin A, toughening agent B, acid or acid anhydride compound C, or by the reaction of vinyl resin A, toughening agent B, acid or acid anhydride compound C and epoxy compound D.

[0016] Wherein, the vinyl resin A includes one or more of hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, hydroxybutyl acrylate, and hydroxybutyl methacrylate.

[0017] Wherein, the toughening agent B includes one or more of caprolactone, polybutylene adipate, polybutylene terephthalate, polylactic acid, and polybutylene succinate.

[0018] The acid or anhydride compound C includes one or more of hexahydrophthalic acid, benzoic acid, pyromellitic anhydride, phthalic anhydride, methyltetrahydrophthalic anhydride, trimellitic anhydride, tetrabromophthalic anhydride, maleic anhydride, 70# anhydride, 647# anhydride, and 308 tung oil anhydride.

[0019] Among them, the epoxy compound D includes one or more of bisphenol A epoxy resin, bisphenol F epoxy resin, resorcinol diglycidyl ether, 1,4-butanediol glycidyl ether and cyclamate glycidyl ether, alkylene glycidyl ether, butyl glycidyl ether, ethylene glycol diglycidyl ether, phenyl glycidyl ether, polypropylene glycol diglycidyl ether, C12-14 fatty glycidyl ether, benzyl glycidyl ether, 1,6-hexanediol diglycidyl ether, neopentyl glycol diglycidyl ether, trimethylolpropane triglycidyl ether, and allyl glycidyl ether.

[0020] The preparation method of the reactive polymer resin plasticizer is specifically as follows:

[0021] Method (A): adding vinyl resin A, toluene and toughening agent B to a reaction vessel, stirring and dissolving at 70-110° C., adding stannous octoate and p-hydroxyanisole; adding acid or anhydride compound C after keeping the temperature for 4 hours; adding epoxy compound D and triphenylphosphine after keeping the temperature for 3 hours when the acid value is reduced by half; keeping the temperature for 6 hours when the epoxy value is reduced to a specific value, distilling the solvent toluene under reduced pressure, and filtering through a filter press to obtain a reactive polymer resin plasticizer;

[0022] The reactive polymer resin plasticizer is obtained by chain extension of vinyl resin A through toughening agent B, and then ring opening of epoxy groups with part of acid or anhydride compound C and part of epoxy compound D to obtain the reactive polymer resin plasticizer.

[0023]

[0024] The reactive polymer resin plasticizer is obtained by chain extension of vinyl resin A through toughening agent B, and then ring opening of epoxy groups with part of acid or anhydride compound C and all epoxy compound D to obtain the reactive polymer resin plasticizer.

[0025]

[0026] Method (B): Add vinyl resin A, toluene, and toughening agent B to a reaction vessel, stir and dissolve at 70-110° C., add stannous octoate and p-hydroxyanisole; after keeping the temperature for 4 hours, add acid or anhydride compound C, keep the temperature for 6 hours, and when the acid value drops to a specific value, distill the solvent toluene under reduced pressure, and filter through a filter press to obtain a reactive polymer resin plasticizer;

[0027] The reactive polymer resin plasticizer is obtained by chain extension of vinyl resin A through toughening agent B, and then reacting with all acid or anhydride compounds C to obtain a reactive polymer resin plasticizer having the structural formula (c):

[0028] A liquid crystal encapsulation sealant is prepared by reacting a curable resin, the above-mentioned reactive polymer resin plasticizer, a curing agent, a filler and a photoinitiator.

[0029] Wherein, the curable resin includes epoxy acrylate UVACURE 1561;

[0030] The curing agent includes one or more of Otsuka Chemical's ADH, SDH, DDH, IDH, SAH, MDH, Ajinomoto PN-23, and MY-25;

[0031] The filler includes one or more of talc, asbestos, silica, diatomaceous earth, smectite, bentonite, calcium carbonate, magnesium carbonate, aluminum oxide, 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;

[0032] The photoinitiator includes at least one of IGM 369 and 651.

[0033] The preparation method of the liquid crystal encapsulation sealant of the present invention specifically comprises: adding a curing resin, then adding a reactive polymer resin plasticizer, a filler, and a photoinitiator in a double planetary stirrer, and vacuum stirring for 20 minutes. After the temperature drops to 25°C, a curing agent is added, and vacuum stirring is performed again for 20 minutes; finally, the liquid crystal encapsulation sealant is obtained by passing through a three-roll mill and a filter press.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] The reactive polymer resin plasticizer of the present invention can achieve appropriate flexibility of the liquid crystal sealant through formulation adjustment according to the required glass transition temperature, thereby achieving high bonding strength. In addition, the reactive polymer resin plasticizer contains active groups such as epoxy groups or carbon-carbon double bonds, so the resin plasticizer can be cross-linked with the main chain resin to form a network to achieve a high cross-linking density, thereby enabling the liquid crystal encapsulation sealant to obtain excellent moisture permeability. DETAILED DESCRIPTION

[0036] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0037] Example 1 Reactive polymer resin plasticizer 1

[0038] 80 g of hydroxyethyl methacrylate, 50 g of toluene and 88 g of caprolactone were added to a three-necked flask equipped with an agitator, a dropping funnel and a condenser, and the mixture was stirred and dissolved at 100° C. 200 ppm of stannous octoate and 1000 ppm of p-hydroxyanisole were added; 91 g of phthalic anhydride was added after being incubated for 4 h, and 124 g of 1,4-butanediol glycidyl ether and 200 ppm of triphenylphosphine were added after being incubated for 3 h when the acid value was reduced by half. The mixture was incubated for 6 h, and the toluene solvent was distilled under reduced pressure when the epoxy value dropped to 0.17 eq / 100 g. The reaction mixture was filtered through a filter press to obtain a reactive polymer resin plasticizer 1.

[0039]

[0040] Example 2 Reactive polymer resin plasticizer 2

[0041] 70 g of hydroxyethyl methacrylate, 50 g of toluene and 77 g of caprolactone were added to a three-necked flask equipped with an agitator, a dropping funnel and a condenser, and the mixture was stirred and dissolved at 100° C. 200 ppm of stannous octoate and 1000 ppm of p-hydroxyanisole were added; 80 g of phthalic anhydride was added after being incubated for 4 h, and 183 g of bisphenol A epoxy resin and 200 ppm of triphenylphosphine were added after being incubated for 3 h when the acid value was reduced by half. The mixture was incubated for 6 h when the epoxy value was reduced to 0.14 eq / 100 g, and the toluene solvent was distilled under reduced pressure. The reaction polymer resin plasticizer 2 was obtained by filter pressing.

[0042]

[0043] Example 3 Reactive polymer resin plasticizer 3

[0044] 70 g of hydroxybutyl acrylate, 50 g of toluene and 106 g of butylene adipate were added to a three-necked flask equipped with an agitator, a dropping funnel and a condenser, and the mixture was stirred and dissolved at 100° C. 200 ppm of stannous octoate and 1000 ppm of p-hydroxyanisole were added. After incubation for 4 h, 48 g of maleic anhydride was added. After incubation for 3 h, 165 g of bisphenol F epoxy resin and 200 ppm of triphenylphosphine were added when the acid value was reduced by half. After incubation for 6 h, when the epoxy value dropped to 0.13 eq / 100 g, the solvent toluene was distilled under reduced pressure and filtered through a filter press to obtain a reactive polymer resin plasticizer 3.

[0045]

[0046] Example 4 Reactive polymer resin plasticizer 4

[0047] 90 g of hydroxyethyl methacrylate, 50 g of toluene, and 100 g of caprolactone were added to a three-necked flask equipped with an agitator, a dropping funnel, and a condenser, and stirred and dissolved at 100° C. 200 ppm of stannous octoate and 1000 ppm of p-hydroxyanisole were added; 102 g of phthalic anhydride was added after incubation for 4 h, and 90 g of hydroxyethyl methacrylate was added after incubation for 3 h when the acid value was reduced by half, and the mixture was incubated for 4 h. When the acid value was reduced to 5 mg KOH / g, the solvent toluene was distilled under reduced pressure and filtered through a filter press to obtain a reactive polymer resin plasticizer 4.

[0048]

[0049] Example 5 Reactive polymer resin plasticizer 5

[0050] 90 g of hydroxyethyl methacrylate, 50 g of toluene and 100 g of caprolactone were added to a three-necked flask equipped with an agitator, a dropping funnel and a condenser, and the mixture was stirred and dissolved at 100° C. 200 ppm of stannous octoate and 1000 ppm of p-hydroxyanisole were added; 102 g of phthalic anhydride was added after being incubated for 4 h, and 118 g of bisphenol A epoxy resin and 200 ppm of triphenylphosphine were added after being incubated for 3 h when the acid value was reduced by half. The mixture was incubated for 6 h when the epoxy value was reduced to 0.02 eq / 100 g, and the toluene solvent was distilled under reduced pressure. The mixture was filtered through a filter press to obtain a reactive polymer resin plasticizer.

[0051]

[0052] Example 6 Reactive polymer resin plasticizer 6

[0053] 90 g of hydroxyethyl methacrylate, 50 g of toluene and 100 g of caprolactone were added to a three-necked flask equipped with a stirrer, a dropping funnel and a condenser, and stirred and dissolved at 100° C. 200 ppm of stannous octoate and 1000 ppm of p-hydroxyanisole were added; 102 g of phthalic anhydride was added after incubation for 4 h, and 90 g of hydroxyethyl methacrylate was added after incubation for 3 h when the acid value was reduced by half, and the solvent toluene was distilled under reduced pressure when the acid value was reduced to 5 mgKOH / g. The reactive polymer resin plasticizer 6 was obtained by filter pressing.

[0054]

[0055] Example 7 Reactive polymer resin plasticizer 7

[0056] 90 g of hydroxyethyl methacrylate, 50 g of toluene and 100 g of caprolactone were added to a three-necked flask equipped with an agitator, a dropping funnel and a condenser, and stirred and dissolved at 100°C. 200 ppm of stannous octoate and 1000 ppm of p-hydroxyanisole were added. After keeping the temperature for 4 hours, 102 g of phthalic anhydride was added. After keeping the temperature for 3 hours, when the acid value was reduced to half, 100 g of cyclanyl glycidyl ether and 200 ppm of triphenylphosphine were added. After keeping the temperature for 6 hours, when the epoxy value dropped to 0.02 eq / 100 g, the solvent toluene was distilled under reduced pressure and filtered through a filter press to obtain a reactive polymer resin plasticizer 7.

[0057]

[0058] Examples 8-14

[0059] In a dual planetary mixer, add 100g of epoxy acrylate UVACURE 1561, followed by 10g of each of the reactive polymer resin plasticizers 1-7, 1g of silica filler, and 1g of photoinitiator Iracure 651. Vacuum stir for 20 minutes. After the temperature drops to 25°C, add 9.6g of ADH and vacuum stir again for 20 minutes. Finally, grind the mixture on a three-roll mill and filter press to obtain a liquid crystal encapsulant.

[0060] Comparative Example

[0061] In a dual planetary mixer, add 100g of epoxy acrylate UVACURE 1561, followed by 1g of silica filler and 1g of photoinitiator Iracure 651. Stir under vacuum for 20 minutes. After the temperature drops to 25°C, add 9.6g of ADH and stir under vacuum again for 20 minutes. Finally, grind the mixture on a three-roll mill and filter press to obtain a liquid crystal encapsulant.

[0062] Determination method:

[0063] Strength: Mix the liquid crystal encapsulation sealants of Examples 8-14 and the comparative example with 1% spacer and apply it to the middle of a 75mm*25mm glass substrate coated with polyimide. Use another substrate to laminate and select samples with a glue diameter of ≤3mm after lamination. The substrate is tested at a wavelength of 365nm with an integrated brightness of 3000mJ / cm 2 UV-curing was performed and the film was placed in a thermostat at 120°C for 1 hour. A universal tensile testing machine was used to apply pressure 5 mm from the end face. To measure bond strength, a strength of less than 5 N / mm was designated as X, a strength of 5-10 N / mm was designated as ○, and a strength of 10 N / mm or more was designated as ◎.

[0064] Moisture permeability: The liquid crystal encapsulation sealants of Examples 8-14 and Comparative Examples were coated with a coating machine to a thickness of 300-400 μm to form a smooth demoulding state, and the wavelength was 365 nm and the integrated light intensity was 3000 mJ / cm 2 UV curing, placed in a constant temperature box at 120℃ for 1 hour, thus obtaining a cured film for moisture permeability measurement. Moisture permeability was measured in a constant temperature and humidity environment at 60℃ according to ASTM E96. In order to test the moisture permeability, the moisture permeability was less than 20g / m 2 ·24h is considered as ◎, and the moisture permeability is 20-40g / m 2 · 24h is considered as ○, and the moisture permeability exceeds 40g / m 2 ·24h is considered as X.

[0065] The experimental results are shown in the following table.

[0066]

[0067]

[0068] The above experimental results demonstrate that the reactive polymer resin plasticizer of the present invention can flexibly adjust the glass transition temperature of the sealant, thereby achieving suitable flexibility. This demonstrates that the sealant of the present invention is a sealant for liquid crystal display elements that exhibits excellent bonding strength and moisture resistance.

[0069] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A reactive polymer resin plasticizer, characterized in that: Its structure is 2. The method for preparing the reactive polymer resin plasticizer according to claim 1, wherein: 90 g of hydroxyethyl methacrylate, 50 g of toluene and 100 g of caprolactone were added to a three-necked flask equipped with an agitator, a dropping funnel and a condenser, and stirred and dissolved at 100° C. 200 ppm of stannous octoate and 1000 ppm of p-hydroxyanisole were added; 102 g of phthalic anhydride was added after keeping the temperature for 4 h, and 100 g of cyprodinil glycidyl ether and 200 ppm of triphenylphosphine were added after keeping the temperature for 3 h when the acid value was reduced to half. The temperature was kept for 6 h, and the solvent toluene was distilled under reduced pressure when the epoxy value dropped to 0.02 eq / 100 g. The reactive polymer resin plasticizer was obtained by filtering through a filter press.

3. The liquid crystal encapsulation sealant prepared from the reactive polymer resin plasticizer according to claim 1, characterized in that: The invention is prepared by reacting a curable resin, the reactive polymer resin plasticizer according to claim 1, a curing agent, a filler and a photoinitiator.

4. The liquid crystal encapsulation sealant according to claim 3, wherein: The curable resin includes epoxy acrylate UVACURE 1561; The curing agent includes one or more of Otsuka Chemical's ADH, SDH, DDH, IDH, SAH, MDH, Ajinomoto PN-23, and MY-25; The filler includes one or more of talc, asbestos, silica, diatomaceous earth, smectite, bentonite, calcium carbonate, magnesium carbonate, aluminum oxide, 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; The photoinitiator includes at least one of IGM 369 and 651.

5. The method for preparing the liquid crystal encapsulation sealant according to claim 3 or 4, characterized in that: In a double planetary mixer, add curing resin, then add reactive polymer resin plasticizer, filler, and photoinitiator, and vacuum stir for 20 minutes. After waiting for the temperature to drop to 25°C, add curing agent and vacuum stir again for 20 minutes; finally, grind through a three-roll grinder and filter press to obtain liquid crystal encapsulation sealant.

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