Modified liquid photosensitive resin formula for low-contact-angle liquid crystal alignment film printing plate as well as preparation method and use method of modified liquid photosensitive resin formula

Abstract

The invention discloses a modified liquid photosensitive resin formula for a low-contact-angle liquid crystal alignment film printing plate as well as a preparation method and a use method of the modified liquid photosensitive resin formula. The modified liquid photosensitive resin formula comprises a urethane acrylate oligomer, a vinyl unsaturated monomer diluent, a photoinitiator and a modifier. The liquid resin is modified, so that the surface energy of the resin is improved, the contact angle between the resin and ink of an alignment film is reduced, the ink content of a layout groove and the liquid carrying amount of a corresponding glass substrate are increased, then the PI film thickness is increased, and therefore the problem of LTPS pocking marks is solved.

Description

Technical Field

[0001] The present invention relates to the field of polymer photosensitive resin plate flexographic printing, and more specifically, to a modified liquid photosensitive resin formula for a low contact angle liquid crystal alignment film printing plate, and a preparation method and a use method thereof. Background Art

[0002] The main function of photosensitive resin flexible printing plates in the liquid crystal panel display industry is to transfer the liquid crystal alignment film to the electrode forming surface of the glass substrate (TFT / CF) of the liquid crystal display element. At present, "LTPS pitting" is common in the liquid crystal panel display manufacturing industry, resulting in display quality problems such as uneven brightness or pixel failure. From the analysis of the printing process, the "missing printing" of the alignment film ink in some areas on the glass substrate is one of the important reasons for this situation. During the printing process, the ink first adheres to the grooves on the surface of the flexible printing plate and is transferred to the glass substrate of the display original by roller printing. Therefore, the amount of ink stored in the grooves greatly affects the amount of liquid on the glass substrate and the final PI film thickness. The surface energy and contact angle of the resin directly affect the adhesion of the ink on the surface of the flexible plate. Therefore, when the surface energy of the material is high and the contact angle is small, more ink will be filled into the grooves on the surface of the plate, thereby improving the transfer efficiency and solving the problem of "LTPS pitting".

[0003] Flexible resin plates are mainly composed of a resin layer and a base film layer. They will deform to a certain extent during the printing process and will be in contact with various solvents in the alignment film ink for a long time, such as water, N-methylpyrrolidone and other polar solvents. Therefore, they must have good flexibility and excellent solvent resistance. The performance of the resin layer largely determines the application performance of the plate, so the resin itself must have a low polarity and must have good flexibility and solvent resistance, such as polybutadiene polyurethane acrylate. However, low polarity will also reduce surface energy and increase the contact angle with the solvent, thereby reducing the adhesion of the alignment film ink. Summary of the invention

[0004] The purpose of the present invention is to provide a modified liquid photosensitive resin formula for a low contact angle liquid crystal alignment film printing plate, as well as a preparation method and a use method thereof. The liquid resin is modified to increase the resin surface energy to reduce the contact angle with the alignment film ink, increase the ink content of the plate grooves and the corresponding liquid carrying capacity of the glass substrate, thereby increasing the PI film thickness, thereby solving the "LTPS pitting" problem.

[0005] The technical solution adopted by the present invention to solve the technical problem is: a modified liquid photosensitive resin formula for a low contact angle liquid crystal alignment film printing plate, comprising: a polyurethane acrylate oligomer, a vinyl unsaturated monomer diluent, a photoinitiator and a modifier.

[0006] As a further solution of the present invention, it is composed of polyurethane acrylate oligomer, vinyl unsaturated monomer diluent, photoinitiator and modifier.

[0007] As a further solution of the present invention, the polyurethane acrylate oligomer is a polybutadiene-based polyurethane acrylate oligomer, which is composed of one or more polybutadiene-based polyurethane acrylates.

[0008] As a further solution of the present invention, the mass ratio of the polybutadiene-based polyurethane acrylate in the resin formula is 40-80%.

[0009] As a further scheme of the present invention, the vinyl unsaturated monomer diluent is a mixture of one or more of lauryl methacrylate, isobornyl acrylate, tetrahydrofuran acrylate, isodecyl acrylate, trimethylolpropane formal acrylate, dodecyl acrylate, tripropylene glycol diacrylate, dipropylene glycol diacrylate, 1,3-butylene glycol dimethacrylate, 1,4-butylene glycol dimethacrylate, polypropylene glycol diacrylate, 1,2-dodecanediol dimethacrylate, tricyclodecane dimethanol diacrylate, and trimethylolpropane triacrylate.

[0010] As a further solution of the present invention, the vinyl unsaturated monomer diluent accounts for 10-50% of the resin mass ratio in the resin formula.

[0011] As a further solution of the present invention, the photoinitiator is a free radical type photoinitiator, and the mass ratio of the photoinitiator to the resin in the resin formula is 0.1-5%.

[0012] As a further solution of the present invention, the modifier is a silane modifier, and the mass ratio of the silane modifier to the resin in the resin formula is 0.01-5%.

[0013] The present invention also provides a method for preparing a modified liquid photosensitive resin formula for a low contact angle liquid crystal alignment film printing plate, comprising: firstly mixing a vinyl unsaturated monomer diluent and a photoinitiator, adding them into a material barrel and preliminarily stirring them to ensure that the photoinitiator is completely dissolved in the monomer diluent; then adding a polybutadiene type polyurethane acrylate oligomer and a silane modifier in sequence, mixing them, and continuing to stir for 20 to 30 minutes until each component is evenly mixed.

[0014] The present invention also provides a method for using a modified liquid photosensitive resin for a low contact angle liquid crystal alignment film printing plate, comprising: coating the prepared liquid photosensitive resin onto a base film engraved with a certain pattern, and then covering the surface with a layer of PET base film with a certain thickness, and then applying a certain pressure on the surface of the PET base film to achieve the purpose of controlling the thickness and uniformity of the resin, and then performing ultraviolet curing, and finally removing the base film with the pattern at the bottom of the resin after it is completely cured.

[0015] The present invention has at least the following beneficial effects: a. By modifying the resin formula, the contact angle between the resin plate and the PI printing liquid is smaller, and more printing liquid can be stored in the plate microstructure, thereby increasing the amount of printing liquid transferred to the glass substrate, thereby increasing the PI film thickness and effectively solving the "LTPS pitting" problem.

[0016] b. The cured resin plate has excellent resistance to polar solvents and will not be damaged during long-term use with PI liquid containing polar solvents, effectively ensuring the stability of printed products.

[0017] Other advantages, objectives and features of the present invention will be embodied in part through the following description, and in part will be understood by those skilled in the art through study and practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of a transfer device for PI printing liquid of the present invention. DETAILED DESCRIPTION

[0019] The present invention is described in detail and completely below in conjunction with the accompanying drawings. A person of ordinary skill in the art will be able to implement the present invention based on these descriptions. Before describing the present invention in conjunction with the accompanying drawings, it should be particularly pointed out that the technical solutions and technical features provided in each part of the present invention, including the following description, can be combined with each other without conflict.

[0020] In addition, the embodiments of the present invention involved in the following description are generally only a part of the embodiments of the present invention, rather than all the embodiments. Therefore, based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0021] The present invention is further described in detail below in conjunction with the accompanying drawings and implementations, and its specific implementation process is as follows: The present invention provides a modified liquid photosensitive resin formula for a low contact angle liquid crystal alignment film printing plate, comprising: a polyurethane acrylate oligomer, a vinyl unsaturated monomer diluent, a photoinitiator and a modifier. In the formula, the resin is subjected to silane modification treatment, which can form chemical bonds on the resin surface or seal defects and unstable chemical bonds on the resin surface to reduce the invasion of solvent molecules on the site; secondly, after the modification treatment, polar groups are introduced, which increases the surface energy of the material, reduces the contact angle, and makes it easier for polar solvents to spread on the surface.

[0022] The technical solution may also include the following technical details to better achieve the technical effect: it is composed of a polyurethane acrylate oligomer, a vinyl unsaturated monomer diluent, a photoinitiator, and a modifier.

[0023] The technical solution may also include the following technical details to better achieve the technical effect: the polyurethane acrylate oligomer is a polybutadiene-type polyurethane acrylate oligomer, which is composed of one or more polybutadiene-based polyurethane acrylates.

[0024] The technical solution may also include the following technical details to better achieve the technical effect: the mass ratio of polybutadiene-based polyurethane acrylate in the resin formula is 40-80%; preferably, the mass ratio of polybutadiene-based polyurethane acrylate in the resin formula is 55-75%. Polybutadiene-based polyurethane acrylate is the main component of the resin composition. Polybutadiene-based polyurethane acrylate has very good elasticity and flexibility, can recover to its original shape under large deformation, has excellent bonding properties with metals and plastics, and also has excellent resistance to polar solvents. It is a light-curing material with excellent application performance.

[0025] The present technical scheme may also include the following technical details to better achieve the technical effect: the vinyl unsaturated monomer diluent is a mixture of one or more of lauryl methacrylate, isobornyl acrylate, tetrahydrofuran acrylate, isodecyl acrylate, trimethylolpropane formal acrylate, dodecyl acrylate, tripropylene glycol diacrylate, dipropylene glycol diacrylate, 1,3-butanediol dimethacrylate, 1,4-butanediol dimethacrylate, polypropylene glycol diacrylate, 1,2-dodecanediol dimethacrylate, tricyclodecane dimethanol diacrylate, trimethylolpropane triacrylate, etc. The vinyl unsaturated monomer diluent in the resin formula mainly plays a role in reducing the viscosity of the system and participating in the photocuring reaction process.

[0026] The technical solution may also include the following technical details to better achieve the technical effect: the weight ratio of the vinyl unsaturated monomer diluent in the resin formula is 10-50%; preferably, the weight ratio of the vinyl unsaturated monomer diluent in the resin formula is 15-40%.

[0027] The present technical scheme may also include the following technical details to better achieve the technical effect: the photoinitiator is a free radical type photoinitiator, preferably one or more of benzoin and its derivatives, benzyl derivatives, dialkoxyacetophenone, α-hydroxyalkyl phenone, α-aminoalkyl phenone, acylphosphine oxide, etc. This type of photoinitiator undergoes intramolecular cleavage after absorbing light energy to directly generate two or more free radicals, which then react with other molecules to start the polymerization process. The photoinitiator accounts for 0.1~5% of the resin mass ratio in the resin formula, preferably 0.5~3%.

[0028] The technical scheme may also include the following technical details to better achieve the technical effect: the modifier is a silane modifier, preferably a mixture of one or more of an aminosilane modifier, an alcohol silane modifier and a carboxyl silane modifier. The silane modifier has an organic functional group that can chemically react or physically adsorb with the resin. By introducing different organic functional groups, the polarity and surface energy of the material surface can be changed, thereby affecting the wettability and contact angle of the surface. The mass ratio of the silane modifier to the resin in the resin formula is 0.01~5%, preferably 0.1~3%.

[0029] The present invention also provides a method for preparing a modified liquid photosensitive resin formula for a low contact angle liquid crystal alignment film printing plate, comprising: firstly mixing a vinyl unsaturated monomer diluent and a photoinitiator in proportion, adding them into a material barrel and preliminarily stirring them to ensure that the photoinitiator is completely dissolved in the monomer diluent; then successively adding a polybutadiene type polyurethane acrylate oligomer and a silane modifier in a certain proportion, mixing them, and continuing to stir for 20 to 30 minutes until each component is evenly mixed.

[0030] The present invention also provides a method for using a modified liquid photosensitive resin for a low contact angle liquid crystal alignment film printing plate, comprising: coating the prepared liquid photosensitive resin onto a base film engraved with a certain pattern, and then covering the surface with a layer of PET base film with a certain thickness, and then applying a certain pressure on the surface of the PET base film to achieve the purpose of controlling the thickness and uniformity of the resin, and then performing ultraviolet curing, and finally removing the base film with the pattern at the bottom of the resin after it is completely cured.

[0031] Sample preparation and testing of the contact angle between resin and PI liquid: prepare a 4cm×4cm×3mm resin block and 10mL of PI liquid, place the resin block on the contact angle test table, extract the PI liquid into the PI liquid dispenser and install it on the testing instrument, and test the contact angle between the PI liquid and the resin surface using the reference angle measurement method.

[0032] like Figure 1As shown, the transfer of PI printing liquid: the resin printing plate is adhered to the printing cylinder with double-sided tape, and the PI printing liquid is transferred to the grooves on the surface of the resin printing plate through the anilox roller and the thickness adjustment roller. Then the platform moves and the PI printing liquid in the grooves is transferred to the glass substrate. The glass substrate containing the printing liquid is placed in an oven at 80°C and heated for 15 minutes to completely evaporate the liquid solvent.

[0033] Measurement of PI liquid printed film thickness: Use a diamond marking pen to divide the printed glass substrate into 10×10 cm squares and place it under an ellipsometer to measure the PI film thickness after the solvent is completely evaporated.

[0034] In the following example formulations, the commercial products of the ingredients are as follows: Commercial products of polybutadiene polyurethane acrylate: CN8891, Sartomer; SUO-8130, SUO-8628, SUO-H8130, SUO-H8628, SHIN-A T&C; LuCure5494, Runao Chemical.

[0035] Ethylene unsaturated monomers: SR423 NS, SR313, SR833, SR214 NS, Sartomer; not limited to products of Sartomer, the same substances of other companies may also be used.

[0036] Photoinitiator: 184, 1173, KIP-127, TPO-L, Aginmon; Ltcure 1301, Feikai Materials, Benzoin Ether, Aladdin, including but not limited to the products of the above companies, and the same substances of other companies can also be used.

[0037] Commercial products of silane modifiers: A-1100, Momentive; triethoxymethylsilane, MacLean.

[0038] The formula table of Examples 1 to 5 is shown in Table 1.

[0039] Table 1 Comparative Examples 1 and 2 are products used by our company before developing the photosensitive resin of this application. Since Comparative Example 1 is a commercially available product, the specific product cannot be disclosed in the patent due to confidentiality; Comparative Example 2 is a test product of Shaoxing Liufang.

[0040] Experiments were conducted on Examples 1 to 5 and Comparative Examples 1 and 2, and the experimental results are shown in Table 2.

[0041] Table 2 Element Example 1 Example 2 Example 3 Example 4 Example 5 Comparative Example 1 Comparative Example 2 Contact angle between resin plate and PI liquid 59° 51° 55° 47° 43° 63° 53° PI liquid printing film thickness 766Å 830Å 810Å 920Å 988Å 710Å 816Å According to the data in Table 2, it can be seen that Comparative Example 1 is a product purchased by the company (Japan). The contact angle between the surface of the product and the PI liquid is too large, resulting in a low printed film thickness. The printed film thickness of the product in Comparative Example 2 is good with the PI liquid, but the resin and PET are not firmly bonded and separated, resulting in the printing plate being unable to be used normally. However, Examples 1 to 5 of the present application all have good printed film thickness, and the ink content of the resin plate is significantly improved when the contact angle is between 43° and 60°. The PI film thickness is greater than 760 Å, which can solve the problem of "LTPS printing pitting", and the resin layer and the PET layer are not separated during printing in each embodiment.

[0042] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and the implementation modes. They can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to the specific details and the embodiments shown and described herein.

Claims

1. A modified liquid photosensitive resin formulation for a low contact angle liquid crystal alignment film printing plate, characterized in that: include: Polyurethane acrylate oligomers, vinyl unsaturated monomer diluents, photoinitiators and modifiers.

2. The modified liquid photosensitive resin formulation for a low contact angle liquid crystal alignment film printing plate according to claim 1, characterized in that: It is composed of polyurethane acrylate oligomer, vinyl unsaturated monomer diluent, photoinitiator and modifier.

3. The modified liquid photosensitive resin formulation for low contact angle liquid crystal alignment film printing plate according to claim 1 or 2, characterized in that: The polyurethane acrylate oligomer is a polybutadiene-based polyurethane acrylate oligomer, which is composed of one or more polybutadiene-based polyurethane acrylates.

4. The modified liquid photosensitive resin formulation for a low contact angle liquid crystal alignment film printing plate according to claim 3, characterized in that: The mass ratio of polybutadiene-based polyurethane acrylate in the resin formula is 40-80%.

5. The modified liquid photosensitive resin formulation for low contact angle liquid crystal alignment film printing plate according to claim 1 or 2, characterized in that: The vinyl unsaturated monomer diluent is a mixture of one or more of lauryl methacrylate, isobornyl acrylate, tetrahydrofuran acrylate, isodecyl acrylate, trimethylolpropane formal acrylate, dodecyl acrylate, tripropylene glycol diacrylate, dipropylene glycol diacrylate, 1,3-butylene glycol dimethacrylate, 1,4-butylene glycol dimethacrylate, polypropylene glycol diacrylate, 1,2-dodecanediol dimethacrylate, tricyclodecane dimethanol diacrylate, and trimethylolpropane triacrylate.

6. The modified liquid photosensitive resin formulation for a low contact angle liquid crystal alignment film printing plate according to claim 5, characterized in that: The vinyl unsaturated monomer diluent accounts for 10-50% of the resin mass in the resin formula.

7. The modified liquid photosensitive resin formulation for a low contact angle liquid crystal alignment film printing plate according to claim 1 or 2, characterized in that: The photoinitiator is a free radical type photoinitiator, and the mass ratio of the photoinitiator to the resin in the resin formula is 0.1-5%.

8. The modified liquid photosensitive resin formulation for low contact angle liquid crystal alignment film printing plate according to claim 1 or 2, characterized in that: The modifier is a silane modifier, and the mass ratio of the silane modifier to the resin in the resin formula is 0.01-5%.

9. A method for preparing a modified liquid photosensitive resin formulation for a low contact angle liquid crystal alignment film printing plate, characterized in that: include: First, add the vinyl unsaturated monomer diluent and the photoinitiator into the material barrel and stir them preliminarily to ensure that the photoinitiator is completely dissolved in the monomer diluent; Then, polybutadiene polyurethane acrylate oligomer and silane modifier are added in sequence and mixed, and stirring is continued for 20 to 30 minutes until each component is evenly mixed.

10. A method for using a modified liquid photosensitive resin for a low contact angle liquid crystal alignment film printing plate, characterized in that: include: The prepared liquid photosensitive resin is coated on a base film engraved with a certain pattern, and then covered with a layer of PET base film with a certain thickness. Then a certain pressure is applied to the surface of the PET base film to achieve the purpose of controlling the thickness and uniformity of the resin, and then UV curing is performed. Finally, the base film with the pattern at the bottom of the resin is removed after it is completely cured.

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