Liquid crystal alignment primer composition and method of preparing the same

Abstract

The application discloses a liquid crystal orientation primer composition and a preparation method thereof. The liquid crystal orientation primer composition comprises a polyester acrylic resin, a bifunctional monomer, a monofunctional monomer, a photoinitiator, an auxiliary agent and a diluent, wherein the polyester acrylic resin contains a benzene ring and is in a straight chain structure, and the bifunctional monomer is in a straight chain structure. The liquid crystal orientation primer composition is suitable for heat-sensitive substrates such as paper and film, and can improve the color development effect of liquid crystal optical variable ink on the substrates.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of liquid crystal alignment agent for inkjet printing, and particularly relates to a liquid crystal alignment primer composition and a preparation method thereof. BACKGROUND

[0002] The liquid crystal alignment primer provides a constraint force in the use of liquid crystal products to control the alignment of liquid crystals and improve the yield of finished products using liquid crystals. Currently, the preparation of liquid crystal alignment liquid often uses amide acid polymers or mixtures to prepare coatings.

[0003] When the commonly used amide acid polymers or mixtures are used as liquid crystal alignment agents, they need to be dried into films by heating, which is limited in the application to heat-sensitive substrates such as paper and film. SUMMARY

[0004] The present application provides a liquid crystal alignment primer composition and a preparation method thereof to solve the technical problem that the commonly used liquid crystal alignment primer is limited in the application to heat-sensitive substrates such as paper and film in the prior art.

[0005] To solve the above technical problem, the present application adopts a technical solution: providing a liquid crystal alignment primer composition, which comprises: a polyester acrylic resin, a bifunctional monomer, a monofunctional monomer, a photoinitiator, an auxiliary agent and a diluent, wherein the polyester acrylic resin contains a benzene ring and is a straight chain structure, and the bifunctional monomer is a straight chain structure.

[0006] Further, the polyester acrylic resin comprises at least one of polytrimethylene terephthalate, methyl-1,4-phenylene bis(4-(4-(acryloyloxy)butyloxy)benzoate), terephthalyl bis[4-[6-(acryloyloxy)hexyloxy]benzoate], 1,4-bis-[4-(6-acryloyloxyhexyloxy)benzoyloxy]-2-methylbenzene, and 2-methyl-1,4-dihydroxyphenyl (((4-(acryloyloxy)butyloxy)carbonyl)oxy)benzoate.

[0007] Further, the content percentage of the polyester acrylic resin is 20%-30%.

[0008] Further, the bifunctional monomer comprises at least one of cyclohexane dimethanol diacrylate, polyethylene glycol (200) diacrylate, polyethylene glycol (400) diacrylate, polyethylene glycol (600) diacrylate, tripropylene glycol diacrylate, 1,6-hexanediol diacrylate, diethylene glycol diacrylate and dipropylene glycol diacrylate.

[0009] Further, the content percentage of the bifunctional monomer is 15%-25%.

[0010] Further, the monofunctional monomer includes at least one of 3,3,5 trimethylcyclohexane acrylate, tetrahydrofurfuryl acrylate, (4) ethylated nonyl phenol acrylate, trimethylolpropane formal acrylate, 2-phenoxyethyl acrylate, styrene, isobornyl acrylate.

[0011] Further, the content percentage of the monofunctional monomer is 30% to 40%.

[0012] Further, the content percentage of the diluent is 2% to 5%, and the diluent includes at least one of methyl isobutyl ketone, acetone, butanone, dichloromethane.

[0013] Further, the content percentage of the photoinitiator is 5% to 10%, and the content percentage of the auxiliary agent is 0.1% to 1%, and the photoinitiator includes at least one of TPO, 819, 1173, EDB, BDK, 184, 369, BAPO.

[0014] To solve the above technical problems, another technical solution adopted by the present application is to provide a preparation method of a liquid crystal orientation primer composition, which comprises: uniformly stirring polyester acrylate resin, bifunctional monomer, monofunctional monomer and diluent to obtain a first mixed solution, wherein the polyester acrylate resin contains benzene ring and is a straight chain structure, and the bifunctional monomer is a straight chain structure. The photoinitiator and the auxiliary agent are added to the first mixed solution and uniformly stirred to obtain the liquid crystal orientation primer composition.

[0015] The beneficial effects of the present application are that, different from the prior art, the liquid crystal orientation primer composition provided by the present application includes polyester acrylate resin, bifunctional monomer, monofunctional monomer, photoinitiator, auxiliary agent and diluent, wherein the polyester acrylate resin contains benzene ring and is a straight chain structure, and the bifunctional monomer is a straight chain structure. The liquid crystal orientation primer composition provided by the present application takes straight chain resin as the main body, adds monomer and photoinitiator to form a light-cured polyester acrylate primer for the use of liquid crystal ink. The liquid crystal orientation primer composition can make the liquid crystal molecules in the liquid crystal ink directional arrange and has good adhesion. The primer composition can be cured by UV / LED-UV energy, and therefore, can be applied to paper, film and other heat-sensitive substrates, and improve the color development effect of liquid crystal photo-variable ink on such substrates. BRIEF DESCRIPTION OF DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0017] wherein:

[0018] Figure 1 is a flowchart of an embodiment of a method for preparing a liquid crystal alignment primer composition provided in the present application. DETAILED DESCRIPTION

[0019] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present application.

[0020] The liquid crystal alignment primer composition provided in the present application can overcome the shortcomings of the currently commonly used alignment liquid which needs to be baked and dried, and is not suitable for application to heat-sensitive substrates. The liquid crystal alignment primer composition in the present application utilizes the structural characteristics of the resin and monomer, which is conducive to the ordered arrangement of the liquid crystal ink molecules, thereby embodying the optical discoloration effect of the liquid crystal ink. The liquid crystal alignment primer composition can be cured in the mode of UV (Ultra-Violet Ray) or LED-UV (Light Emitting Diode-Ultra-Violet Ray), and has obvious rapid curing and heat-sensitive substrate applicability.

[0021] Specifically, the liquid crystal alignment primer composition in the present application comprises a polyester acrylic resin, a difunctional monomer, a monofunctional monomer, a photoinitiator, an auxiliary agent and a diluent.

[0022] In the present application, the polyester acrylic resin contains a benzene ring and has a straight chain structure. The acrylic resin containing a benzene ring and a straight chain can provide a rigid chain segment. The polyester acrylic resin includes at least one of polytrimethylene terephthalate, methyl-1,4-phenylene bis(4-(4-(acryloyloxy)butyloxy)benzoate), terephthalyl bis[4-[6-(acryloyloxy)hexyloxy]benzoate], 1,4-bis-[4-(6-acryloyloxyhexyloxy)benzoyloxy]-2-methylbenzene, and (((4-(acryloyloxy)butyloxy)carbonyl)oxy)benzoic acid 2-methyl-1,4-diphenol ester.

[0023] The content percentage of the polyester acrylic resin can be 20%-30%, for example, the content of the polyester acrylic resin can be 20%, 21%, 22%, 25%, 26%, 27%, 29% or 30%, etc. The content percentage here refers to the ratio of the mass of the polyester acrylic resin to the total mass of the liquid crystal alignment primer composition.

[0024] Further, the bifunctional monomer is in a straight chain structure. The acrylic resin containing a benzene ring straight chain provides rigid segments which are inter-blocked with flexible segments of the straight chain bifunctional monomer, and after curing, a linear polymer film is formed, and is similar to the monomer structure in the liquid crystal ink, thus inducing the alignment of the liquid crystal molecules, thereby improving the color development effect.

[0025] Optionally, the bifunctional monomer can include at least one of cyclohexane dimethanol diacrylate, polyethylene glycol (200) diacrylate, polyethylene glycol (400) diacrylate, polyethylene glycol (600) diacrylate, tripropylene glycol diacrylate, 1,6-hexanediol diacrylate, diethylene glycol diacrylate, and dipropylene glycol diacrylate.

[0026] The content percentage of the bifunctional monomer is 15% to 25%. For example, the content of the bifunctional monomer can be 15%, 17%, 19%, 20%, 22%, 23%, 24%, or 25%, etc. The content percentage of the bifunctional monomer here refers to the ratio of the mass of the bifunctional monomer to the total mass of the liquid crystal alignment primer combination.

[0027] Further, the monofunctional monomer contains a ring structure, and the monofunctional monomer functions as an end-capping agent. Specifically, the monofunctional monomer can include at least one of 3,3,5 trimethylcyclohexane acrylate, tetrahydrofurfuryl acrylate, (4) ethylated nonyl phenol acrylate, trimethylolpropane formal acrylate, 2-phenoxyethyl acrylate, styrene, and isobornyl acrylate.

[0028] The content percentage of the monofunctional monomer is 30% to 40%. For example, the content of the monofunctional monomer can be 30%, 32%, 33%, 35%, 36%, 37%, 38%, or 40%, etc.

[0029] The diluent can be a ketone or chloroalkane solvent, and the diluent functions to adjust the viscosity of the system. Specifically, the diluent can include at least one of methyl isobutyl ketone, acetone, butanone, and dichloromethane.

[0030] Further, the content percentage of the diluent can be 2% to 5%. For example, the content of the diluent can be 2%, 3%, 4%, or 5%, etc.

[0031] Further, the photoinitiator plays a role in curing, and the initiator can include at least one of TPO (Diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide), Darocur® 819, Irgacure® 1173, EDB (Ethyl-4-dimethylamino benzoate), BDK (Benzil Dimethyl Ketal), Irgacure® 184, Irgacure® 369, and BAPO (bis-acylphosphin oxide).

[0032] The content percentage of the photoinitiator can be 5% to 10%, for example, the content of the photoinitiator can be 5%, 6%, 7%, 8%, 9%, or 10%, etc.

[0033] The auxiliary agent can include at least one of YK-UV 3500 of Germany BYK Company, general wetting dispersant TEGO Dispers 655 of Germany Degussa Company, and acrylic-based leveling agent Letch CFC-46L of Korea Changhua CFC Company.

[0034] The content percentage of the auxiliary agent is 0.1% to 1%, for example, the content of the auxiliary agent can be 0.1%, 0.3%, 0.5%, 0.7%, 0.8%, and 1%, etc.

[0035] Therefore, the liquid crystal alignment primer composition provided by the present application adopts a linear acrylic resin containing a benzene ring to provide a rigid segment, which is inter-blocked with a flexible segment of a linear difunctional monomer, and forms a linear polymer film after curing, and is similar to the monomer structure in the liquid crystal ink, which has an inducing effect and is conducive to the alignment of liquid crystal molecules, thereby improving the color development effect. The monofunctional monomer plays a role in capping, the photoinitiator plays a role in curing, and a small amount of diluent plays a role in adjusting the viscosity of the system. The liquid crystal alignment primer composition obtained by the present application can make the liquid crystal molecules align, has good adhesion, and in addition, the liquid crystal alignment primer composition can be cured by UV / LED-UV, rather than the traditional thermal curing method, so that the liquid crystal alignment composition can be applied to heat-sensitive substrates.

[0036] In the following, several examples will be listed to detect the properties of the primer composition provided by the present application. The specific detection method includes:

[0037] Adhesion test: according to the GB9286-98 crosshatch test standard, a crosshatch scraper is used on the cured coating at 1cm 2Grid spacing 1x1mm in the area, using 3M600&610 tape attached to the grid area, after beating the paste, tear off with force, view the shedding area at the cut, judge the adhesion level ≤15%.

[0038] Viscosity test: The viscosity of the primer liquid was tested using a rotary viscometer, with a viscosity range of 1500-3000 cps.

[0039] Color change effect: Use Ricoh GEN5 printing test platform, print 5mm*5mm solid block, visually observe the front gold red and the side blue green.

[0040] Example 1:

[0041] The preparation of the optically variable ink is carried out according to the reference patent document WO2014201997A1 (publication number).

[0042] Primer: Take 20 parts (4-(((4-(acryloyloxy)butoxy)carbonyl)oxy)benzoic acid 2-methyl-1,4-diphenol ester, 25 parts 1,6-hexanediol diacrylate, 40 parts 2-phenoxyethyl acrylate and 4.9 parts methyl isobutyl ketone, stir for 10 min using a disperser, after uniform stirring, add 10 parts TPO and 0.1 parts YK-UV 3500, continue to stir for 30 min, get liquid crystal orientation primer composition.

[0043] Spray the liquid crystal orientation primer composition and then cure it to test the primer performance.

[0044] Grid test: shedding area 8%;

[0045] Test viscosity using NDJ-1 type rotary viscometer: 2360 cps.

[0046] Example 2:

[0047] Take 25 parts of p-phenyl bis[4-[6-(acryloyloxy)hexyloxy]benzoic acid] ester, 25 parts of 1,6-hexanediol diacrylate, 35 parts of 2-phenoxyethyl acrylate and 4.9 parts of dichloromethane, stir for 10 min using a disperser, after uniform stirring, add 10 parts of 819 and 0.1 parts of Dispers655, continue to stir for 30 min, get liquid crystal orientation primer composition.

[0048] Spray the liquid crystal orientation primer composition and then cure it to test the primer performance.

[0049] Grid test: shedding area 10%;

[0050] Test viscosity using NDJ-1 type rotary viscometer: 2440 cps.

[0051] Example 3:

[0052] Take 10 parts of polytrimethylene terephthalate, 15 parts of 3-methyl-1, 4-phenylene bis (4- (4- (acryloxy) butoxy) benzoate), 25 parts of dipropylene glycol diacrylate, 15 parts of 2- phenoxyethyl acrylate, 22 parts of isobornyl acrylate and 4.9 parts of acetone are stirred and dispersed for 10 min using a disperser, 8 parts of 184 and 0.1 parts of Letch CFC-46L are added after uniform stirring, and stirring and dispersion are continued for 30 min to obtain a liquid crystal alignment primer composition.

[0053] The liquid crystal alignment primer composition is sprayed and cured, and the primer performance is tested.

[0054] Cross-hatch test: 10% area of peeling off;

[0055] The viscosity is tested using an NDJ-1 type rotary viscometer: 2340 cps.

[0056] Example 4:

[0057] Take 10 parts of polytrimethylene terephthalate, 15 parts of 3-methyl-1, 4-phenylene bis (4- (4- (acryloxy) butoxy) benzoate), 25 parts of dipropylene glycol diacrylate, 15 parts of 2- phenoxyethyl acrylate, 22 parts of isobornyl acrylate and 4.9 parts of acetone are stirred and dispersed for 10 min using a disperser, 8 parts of 184 and 0.1 parts of Letch CFC-46L are added after uniform stirring, and stirring and dispersion are continued for 30 min to obtain a liquid crystal alignment primer composition.

[0058] The liquid crystal alignment primer composition is sprayed and cured, and the primer performance is tested.

[0059] Cross-hatch test: 12% area of peeling off;

[0060] The viscosity is tested using an NDJ-1 type rotary viscometer: 2460 cps.

[0061] The liquid crystal alignment primer composition of the present application comprises a benzene ring-containing linear acrylate resin and a linear bifunctional monomer, a monofunctional monomer, a photoinitiator, an auxiliary agent and a small amount of a diluent. The primer composition is beneficial to the ordered arrangement of liquid crystal molecules in the liquid crystal ink, thereby realizing the optical discoloration effect of the ink. Moreover, the primer composition can overcome the shortcomings of the currently commonly used alignment liquid, i.e., the need for baking and drying, which is not conducive to the application of heat-sensitive substrates. The primer composition of the present application can be cured by UV / LED-UV, has the advantages of rapid curing and applicability to heat-sensitive substrates.

[0062] The present application also provides a preparation method of a liquid crystal alignment primer composition, which is shown in Figure 1 Figure 1 ​is a flowchart of an embodiment of a preparation method of a liquid crystal alignment primer composition provided by the present application. Specifically, the preparation method comprises the following steps.

[0063] S11: uniformly stirring the polyester acrylic resin, the bifunctional monomer, the monofunctional monomer and the diluent to obtain a first mixture, wherein the polyester acrylic resin contains benzene rings and is in a linear structure, and the bifunctional monomer is in a linear structure.

[0064] An appropriate amount of the polyester acrylic resin, the bifunctional monomer, the monofunctional monomer and the diluent are taken and mixed and stirred. For example, the mixture can be stirred and dispersed by a disperser for about 10 minutes to obtain the first mixture. The types and percentages of the polyester acrylic resin, the bifunctional monomer, the monofunctional monomer and the diluent can be referred to the above description of the embodiments, and will not be repeated here.

[0065] S12: adding the photoinitiator and the auxiliary agent to the first mixture and uniformly stirring to obtain the liquid crystal alignment primer composition.

[0066] After obtaining the first mixture, the photoinitiator and the auxiliary agent are added to the first mixture, and then uniformly stirred, for example, for about 30 minutes to obtain the liquid crystal alignment primer composition. The types and contents of the photoinitiator and the auxiliary agent can be referred to the above description of the embodiments, and will not be repeated here.

[0067] The preparation method is simple and low in cost. The liquid crystal alignment primer composition obtained by the method can make liquid crystal molecules arrange in a direction, has good adhesion, and can be cured by UV / LED-UV energy, and thus can be applied to paper, film and other heat-sensitive substrates to improve the color development effect of liquid crystal photo-variable ink on such substrates.

[0068] The above description is only an embodiment of the present application, and does not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation, or direct or indirect application in other related technical fields, is also included in the patent protection scope of the present application.

Claims

1. A liquid crystal alignment primer composition characterized by comprising: The liquid crystal orientation primer composition comprises: a polyester acrylic resin, a bifunctional monomer, a monofunctional monomer, a photoinitiator, an auxiliary agent and a diluent, The polyester acrylic resin comprises at least one of methyl-1,4-phenylene bis(4-(4-(acryloyloxy) butoxy) benzoate), p-phenyl bis[4-[6-(acryloyloxy) hexyloxy] benzoic acid] ester, 1,4-bis-[4-(6-acryloyloxy hexyloxy) benzoyloxy]-2-methyl benzene, 4-(((4-(acryloyloxy) butoxy) carbonyl) oxy) benzoic acid 2-methyl-1,4-diphenol ester. The content percentage of the polyester acrylic resin is 20%-30%. The bifunctional monomer comprises at least one of cyclohexane dimethanol diacrylate, polyethylene glycol 200 diacrylate, polyethylene glycol 400 diacrylate, polyethylene glycol 600 diacrylate, tripropylene glycol diacrylate, 1,6-hexanediol diacrylate, diethylene glycol diacrylate and dipropylene glycol diacrylate.

2. The liquid crystal alignment primer composition according to claim 1, characterized by The content percentage of the bifunctional monomer is 15%-25%.

3. The liquid crystal alignment primer composition according to claim 1, wherein The monofunctional monomer comprises at least one of 3,3,5-trimethylcyclohexane acrylate, tetrahydrofurfuryl acrylate, trimethylolpropane formal acrylate, 2-phenoxyethyl acrylate, styrene and isobornyl acrylate.

4. The liquid crystal alignment primer composition according to claim 3, characterized by The content percentage of the monofunctional monomer is 30%-40%.

5. The liquid crystal alignment primer composition according to claim 1, wherein The content percentage of the diluent is 2%-5%, and the diluent comprises at least one of methyl isobutyl ketone, acetone, butanone and dichloromethane.

6. The liquid crystal alignment primer composition according to claim 5, wherein The content percentage of the photoinitiator is 5%-10%, and the content percentage of the auxiliary agent is 0.1%-1%, 7. The liquid crystal alignment primer composition according to claim 1, wherein The photoinitiator comprises at least one of TPO, 819, 1173, EDB, BDK, 184, 369 and BAPO.

8. The liquid crystal alignment primer composition according to claim 1, wherein The preparation method comprises: ​ 9. A method of preparing a liquid crystal alignment primer composition, characterized by, ​ Polyester acrylic resin, bifunctional monomer, monofunctional monomer and diluent are stirred to obtain a first mixture, wherein the polyester acrylic resin contains benzene ring and is linear structure, the bifunctional monomer is linear structure, the polyester acrylic resin is used to provide rigid segment, the rigid segment is inter-blocked with flexible segment of the bifunctional monomer, linear polymer film is formed after curing to induce liquid crystal molecule directional arrangement, the monofunctional monomer is used for end capping, the polyester acrylic resin includes at least one of methyl-1,4-phenylene bis(4-(4-(acryloyloxy) butoxy) benzoate), p-benzene bis[4-[6-(acryloyloxy) hexyloxy] benzoic acid] ester, 1,4-bis-[4-(6-acryloyloxy hexyloxy) benzoyloxy]-2-methyl benzene, 4-(((4-(acryloyloxy) butoxy) carbonyl) oxy) benzoic acid 2-methyl-1,4-diphenol ester; Photo initiator and auxiliary agent are added in the first mixture and stirred to obtain the liquid crystal orientation primer composition.

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