阅读说明：本技术 光硬化性喷墨用墨水 (Photocurable ink for inkjet ) 是由 吉富康亮 诸越信太 高桥敏行 及川尚夫 于 2018-04-25 设计创作，主要内容包括：本发明的课题在于提供一种在微透镜或电子零件的制造中有用的、挥发性低的光硬化性喷墨用墨水。本发明的光硬化性喷墨用墨水含有多官能(甲基)丙烯酸酯(A)、评价法1中的非挥发度为75％以上、粘度为1mPa·s～70mPa·s(25℃)的单官能(甲基)丙烯酸酯(B)、以及光聚合引发剂(C),且25℃下的粘度为1mPa·s～100mPa·s；[评价法1]以单官能(甲基)丙烯酸酯(B)：季戊四醇四(三)丙烯酸酯＝25：45的重量比率混合,而制作评价液。(1)测定5cm×5cm的玻璃基板的重量。(2)在(1)的玻璃基板上滴加评价液,利用旋转涂布以涂布重量成为25mg±2mg的误差的方式涂布。(3)测定(2)的涂布有评价液的玻璃基板的重量。(4)自(3)的重量减去(1)的重量而计算评价液的涂布重量。(5)在50℃的热板上对(3)的涂布有评价液的玻璃基板进行15分钟加热。(6)测定(5)的加热后的玻璃基板的重量,减去(1)的重量而计算评价液的余量。(7)根据以下计算式计算出非挥发度。非挥发度％＝余量÷涂布重量×100。(The present invention addresses the problem of providing a low-volatility photocurable inkjet ink useful for the production of microlenses or electronic components. The photocurable inkjet ink of the present invention comprises a polyfunctional (meth) acrylate (A), a monofunctional (meth) acrylate (B) having a non-volatility of 75% or more and a viscosity of 1 to 70 mPas (25 ℃) in evaluation method 1, and a photopolymerization initiator (C), and has a viscosity of 1 to 100 mPas at 25 ℃; [ evaluation method 1] A monofunctional (meth) acrylate (B): pentaerythritol tetra (tri) acrylate 25: 45 by weight ratio, to prepare an evaluation solution. (1) The weight of the glass substrate 5cm × 5cm was measured. (2) The evaluation liquid was dropped on the glass substrate of (1) and applied by spin coating so that the application weight became an error of 25 mg. + -.2 mg. (3) The weight of the glass substrate coated with the evaluation solution of (2) was measured. (4) The weight of (1) was subtracted from the weight of (3) to calculate the coating weight of the evaluation liquid. (5) The glass substrate coated with the evaluation liquid of (3) was heated on a hot plate at 50 ℃ for 15 minutes. (6) The weight of the heated glass substrate in (5) was measured, and the weight in (1) was subtracted to calculate the remaining amount of the evaluation liquid. (7) The non-volatility was calculated according to the following calculation formula. Nonvolatile% + balance ÷ coating weight × 100.)

1. A photocurable inkjet ink comprising a polyfunctional (meth) acrylate (A), a monofunctional (meth) acrylate (B) having a non-volatility of 75% or more and a viscosity of 1 to 70 mPas (25 ℃) in an evaluation solution of evaluation method 1, and a photopolymerization initiator (C), wherein the photocurable inkjet ink has a viscosity of 1 to 100 mPas at 25 ℃;

[ evaluation method 1]

With a monofunctional (meth) acrylate (B): pentaerythritol tetra (tri) acrylate 25: 45 in a weight ratio to prepare an evaluation solution;

(1) Measuring the weight of a glass substrate of 5cm × 5 cm;

(2) Dropping the evaluation solution on the glass substrate of (1), and applying by spin coating so that the application weight is within an error of 25mg ± 2 mg;

(3) Measuring the weight of the glass substrate coated with the evaluation solution in the step (2);

(4) Subtracting the weight of (1) from the weight of (3) to calculate the coating weight of the evaluation liquid;

(5) Heating the glass substrate coated with the evaluation liquid of (3) on a hot plate at 50 ℃ for 15 minutes;

(6) Measuring the weight of the heated glass substrate in the step (5), and subtracting the weight in the step (1) to calculate the residual amount of the evaluation liquid;

(7) Calculating the non-volatility according to the following calculation formula; nonvolatile% + balance ÷ coating weight × 100.

2. The photo-curable inkjet ink according to claim 1, wherein the polyfunctional (meth) acrylate (a) is at least one or more compounds selected from the group consisting of compounds represented by formula (1) or formula (3);

[ solution 1]

(in the formula (1), R¹Is hydrogen, C1-C6 alkyl or hydroxymethyl, R²、R³And R⁴Each independently is hydrogen or methyl, R⁵、R⁶、R⁷And R⁸Each independently an alkylene group having 1 to 6 carbon atoms, k is 0 or 1, and l, m and n are each independently an integer of 0 to 10; ) In the formula (3), R¹³And R¹⁴Each independently is hydrogen or methyl, R¹⁵And R¹⁶Each independently an alkylene group having 1 to 6 carbon atoms, R¹⁷Is a divalent organic radical or a single bond, R¹⁸And R¹⁹Each independently is-O-or a single bond; wherein, in R¹⁷In the case of a single bond, R¹⁸And R¹⁹Is either-O-or bisAll the squares are single bonds; c and d are each independently an integer of 0 to 10).

3. The photo-curable inkjet ink according to claim 2, wherein the polyfunctional (meth) acrylate (a) is a compound in which k is 0 or 1 in the formula (1) and l + m + n is 0, or R in the formula (3)¹⁵And R¹⁶Each of which is an alkylene group having 2 carbon atoms.

4. The photo-curable inkjet ink according to claim 3, wherein the polyfunctional (meth) acrylate (A) is at least one compound selected from the group consisting of glycerol tri (meth) acrylate, trimethylolethane tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, bisphenol A ethylene oxide-modified diacrylate and bisphenol F ethylene oxide-modified diacrylate.

5. The photo-curable inkjet ink according to claim 4, wherein the polyfunctional (meth) acrylate (A) is pentaerythritol tri (meth) acrylate or bisphenol F ethylene oxide-modified diacrylate.

6. The photo-curable inkjet ink according to any one of claims 1 to 5, wherein the monofunctional (meth) acrylate (B) is a compound having one group selected from a vinyl ether group and an allyl ether group.

7. the photo-curable inkjet ink according to claim 6, wherein the monofunctional (meth) acrylate (B) is a compound represented by formula (2);

[ solution 2]

(in the formula, R⁹Is hydrogen or methyl, R¹⁰And R¹¹Each independently hydrogen or methyl, a is an integer of 1 to 10, b is 0 or 1, R¹²Is hydrogen or carbonAn alkyl group having a number of 1 to 11).

8. The photo-curable inkjet ink according to claim 7, wherein R in the formula (2)¹⁰And R¹¹Is hydrogen, a is an integer of 1 or 2, b is 0, R¹²Is hydrogen.

9. The photo-curable inkjet ink according to claim 8, wherein the monofunctional (meth) acrylate (B) is 2-vinyloxyethyl (meth) acrylate or 2- (2-vinyloxyethoxy) ethyl (meth) acrylate.

10. The photo-curable inkjet ink according to claim 9, wherein the monofunctional (meth) acrylate (B) is 2- (2-ethyleneoxyethoxy) ethyl (meth) acrylate.

11. The inkjet ink according to any one of claims 1 to 10, wherein 10 to 75 wt% of the polyfunctional (meth) acrylate (a), 20 to 90 wt% of the monofunctional (meth) acrylate (B), 1 to 20 wt% of the photopolymerization initiator (C) (wherein the total amount is not more than 100 wt%) are contained, relative to the total weight of the photocurable inkjet ink.

12. A cured film comprising a cured product of the photocurable inkjet ink according to any one of claims 1 to 11.

13. A microlens comprising a cured product of the photocurable inkjet ink according to any one of claims 1 to 12.

14. A protective film comprising a cured product of the photocurable inkjet ink according to any one of claims 1 to 12.

15. An optical part having the microlens as claimed in claim 13.

16. An electronic part having the protective film according to claim 14.

17. A display element having a part according to claim 15 or 16.

Technical Field

The present invention relates to a photocurable inkjet ink which can be preferably used for manufacturing optical devices such as image display devices. More specifically, the present invention relates to an ink for forming a microlens, which is used in an optical system for improving the efficiency of light utilization of a device or stereoscopic imaging of an image.

The present invention also relates to a photocurable inkjet ink which can be preferably used for manufacturing electronic components such as semiconductor devices and flexible wiring boards. More specifically, the present invention relates to an ink for forming a patterned insulating material such as a buffer layer for a wafer level package, a rewiring insulating material, a barrier material, an underfill material, or a cover film for a flexible wiring board.

Background

As for the microlens, application as a light guide plate for an image display device using a fine uneven structure thereof has been studied, and application as a material for a 3D image display element or an anti-counterfeiting device is considered because a special visual effect can be exhibited (for example, patent documents 1 and 2).

The microlens is formed by injection molding using a mold. However, when a small number of many kinds of microlenses are manufactured by the above method, a mold corresponding to the product design needs to be newly manufactured, and an increase in the number of manufacturing steps becomes a problem. In recent years, electronic components and the like are required to have a high pattern shape definition, and in order to realize the fine processing, for example, when a pattern of a semiconductor integrated circuit is formed by a photolithography technique, the high precision is required.

On the other hand, a method of directly forming a microlens on a substrate surface using an ink jet method as a manufacturing method having a high degree of freedom in design has been proposed (for example, patent documents 3 and 4). The method for manufacturing a microlens using the ink jet method is expected in that patterning can be easily controlled by a computer or the like, and therefore, the number of manufacturing steps does not change even in the case of production of a small number of various products, and manufacturing cost can be reduced.

In the production of electronic components such as semiconductor packages and flexible wiring boards, dry film resists or liquid photoresists have been used as protective films for protecting conductors such as metal wiring or electrodes constituting a predetermined circuit pattern formed on a substrate and the substrate.

However, since the method of forming the protective film is a photolithography method, it takes a long time and a large amount of cost to produce a photomask, and since pattern exposure using a photomask is required, there is a problem that the equipment investment amount increases and the steps become complicated.

In recent years, in order to solve these problems, a method of forming a protective film by directly applying ink onto a substrate using an ink jet method has been developed (for example, patent document 10). The method does not require pattern exposure that has been necessary, and therefore, the method is expected to be low in equipment investment and high in material yield.

In order to realize a fine pattern shape by the ink jet method, it is required to reduce the viscosity of the ink to be used. In order to reduce the viscosity of the ink, the following measures are taken: a monofunctional low-molecular monomer is used in combination as a reactive diluent in a photocurable resin component. As the monomer usable as the reactive diluent, a large number of monomers such as acrylic monomers and vinyl monomers are known. Among them, acrylates generally have excellent photo-curability, but on the other hand, since they are rich in odor and highly irritating to the coating film, photo-curable resins containing the above monomers have a disadvantage of impairing the working environment. Further, acrylates having a lower viscosity have a problem that they are highly volatile and difficult to form into fine pattern shapes.

these acrylate monomers are modified with alkylene oxide or epsilon-caprolactone to reduce odor and skin irritation, but the modified acrylate has disadvantages that the hardening rate or hardness of the hardened product is lowered and the viscosity of the ink is increased.

Patent document 5 discloses that a composition containing a reactive oligomer as a urethane poly (meth) acrylate obtained by a reaction of a polyol with a polyisocyanate and a hydroxyl group-containing (meth) acrylate is effective for reducing odor and skin irritation, but the composition has a viscosity of several thousand or more and thus is difficult to use as an ink for inkjet.

Patent document 6 discloses that a composition having a surface tension of 25mN/m to 35mN/m is effective for forming fine droplets by an ink jet method, but the volatility of the monomer is not sufficiently discussed.

Patent document 7 discloses an ink jet ink containing a trifunctional (meth) acrylate (a), a monofunctional (meth) acrylate (B), a photopolymerization initiator (C), and a surfactant (D) having a photocrosslinkable functional group, and relates to an ink jet ink that can be used for a base treatment for forming a microlens, and does not assume the microlens itself.

Patent document 8 discloses an ink composition for forming a microlens, which contains a compound (a) having a specific structure, another radical polymerizable compound (B), and a photopolymerization initiator (C). Patent document 9 discloses an ink for inkjet containing (meth) acrylamide (a) having a specific structure, (meth) acrylamide (B) having a cyclic structure, (meth) acrylate (C) and a photopolymerization initiator (D). All of the ink compositions are ink compositions for facilitating the design of the height or shape of the microlens, and no description is given of the volatility of the monomer.

Disclosure of Invention

Problems to be solved by the invention

Under the circumstances, an object of the present invention is to provide a low-volatility photocurable ink which has a low viscosity and can be printed by an ink jet method and which can form a fine pattern shape such as a microlens or a protective film.

Means for solving the problems

The present inventors have found that a photocurable inkjet ink containing a polyfunctional (meth) acrylate (a), a monofunctional (meth) acrylate (B) having low volatility, and a photopolymerization initiator (C) and having a viscosity of 1mPa · s to 100mPa · s at 25 ℃ is suitable for forming fine microlenses and protective films, and have completed the present invention based on the finding.

Namely, the present invention includes the following items.

[1] A photocurable inkjet ink comprising a polyfunctional (meth) acrylate (A), a monofunctional (meth) acrylate (B) having a non-volatility of 75% or more and a viscosity of 1 to 70 mPas (25 ℃) in an evaluation liquid in evaluation method 1, and a photopolymerization initiator (C), wherein the viscosity at 25 ℃ is 1 to 100 mPas.

[ evaluation method 1]

With a monofunctional (meth) acrylate (B): pentaerythritol tetra (tri) acrylate 25: 45 by weight ratio, to prepare an evaluation solution.

(1) The weight of the glass substrate 5cm × 5cm was measured.

(2) The evaluation liquid was dropped on the glass substrate of (1) and applied by spin coating so that the application weight became an error of 25 mg. + -.2 mg.

(3) The weight of the glass substrate coated with the evaluation solution of (2) was measured.

(4) The weight of (1) was subtracted from the weight of (3) to calculate the coating weight of the evaluation liquid.

(5) The glass substrate coated with the evaluation liquid of (3) was heated on a hot plate at 50 ℃ for 15 minutes.

(6) The weight of the heated glass substrate in (5) was measured, and the weight in (1) was subtracted to calculate the remaining amount of the evaluation liquid.

(7) The non-volatility was calculated according to the following calculation formula. Non-volatility% + balance ÷ coating weight × 100

[2] The photocurable inkjet ink according to [1], wherein the polyfunctional (meth) acrylate (A) is at least one compound selected from the group consisting of compounds represented by the formula (1) or (3).

[ solution 1]

(in the formula (1), R¹Is hydrogen, C1-C6 alkyl or hydroxymethyl, R²、R³And R⁴Are respectively provided withIndependently is hydrogen or methyl, R⁵、R⁶、R⁷And R⁸Each independently an alkylene group having 1 to 6 carbon atoms, k is 0 or 1, and l, m and n are each independently an integer of 0 to 10. In the formula (3), R¹³And R¹⁴Each independently is hydrogen or methyl, R¹⁵And R¹⁶Each independently an alkylene group having 1 to 6 carbon atoms, R¹⁷Is a divalent organic radical or a single bond, R¹⁸And R¹⁹Are each independently-O-or a single bond. Wherein, in R¹⁷In the case of a single bond, R¹⁸And R¹⁹Either is-O-or both are single bonds. c and d are each independently an integer of 0 to 10. )

[3]According to [2]]The photo-curable ink jet ink wherein the polyfunctional (meth) acrylate (A) is a compound of the formula (1) wherein k is 0 or 1 and l + m + n is 0, or the formula (3) wherein R is¹⁵And R¹⁶Each of which is an alkylene group having 2 carbon atoms.

[4] The photocurable inkjet ink according to [3], wherein the polyfunctional (meth) acrylate (A) is at least one compound selected from the group consisting of glycerol tri (meth) acrylate, trimethylolethane tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, bisphenol A ethylene oxide-modified diacrylate and bisphenol F ethylene oxide-modified diacrylate.

[5] The photocurable inkjet ink according to [4], wherein the polyfunctional (meth) acrylate (A) is pentaerythritol tri (meth) acrylate or bisphenol F ethylene oxide-modified diacrylate.

[6] The photocurable inkjet ink according to any one of [1] to [5], wherein the monofunctional (meth) acrylate (B) is a compound having one group selected from a vinyl ether group and an allyl ether group.

[7] The photocurable inkjet ink according to [6], wherein the monofunctional (meth) acrylate (B) is a compound represented by the formula (2).

[ solution 2]

(in the formula, R⁹Is hydrogen or methyl, R¹⁰And R¹¹Each independently hydrogen or methyl, a is an integer of 1 to 10, b is 0 or 1, R¹²Is hydrogen or C1-11 alkyl. )

[8]According to [7]The photo-curable ink jet ink wherein R in the formula (2)¹⁰And R¹¹Is hydrogen, a is an integer of 1 or 2, b is 0, R¹²Is hydrogen.

[9] The photocurable inkjet ink according to [8], wherein the monofunctional (meth) acrylate (B) is 2-vinyloxyethyl (meth) acrylate or 2- (2-vinyloxyethoxy) ethyl (meth) acrylate.

[10] The photocurable inkjet ink according to [9], wherein the monofunctional (meth) acrylate (B) is 2- (2-ethyleneoxyethoxy) ethyl (meth) acrylate.

[11] The inkjet ink according to any one of [1] to [10], wherein the photocurable inkjet ink contains 10 to 75 wt% of the polyfunctional (meth) acrylate (A), 20 to 90 wt% of the monofunctional (meth) acrylate (B), and 1 to 20 wt% of the photopolymerization initiator (C) (wherein the total amount is not more than 100 wt%).

[12] a cured film comprising the cured product of the photocurable inkjet ink according to any one of [1] to [11 ].

[13] A microlens comprising the cured product of the photocurable inkjet ink according to any one of [1] to [12 ].

[14] A protective film comprising a cured product of the photocurable inkjet ink according to any one of [1] to [12 ].

[15] An optical part having the microlens according to [13 ].

[16] An electronic part having the protective film according to [14 ].

[17] A display element having the part according to [15] or [16 ].

ADVANTAGEOUS EFFECTS OF INVENTION

The photocurable inkjet ink of the present invention is composed of a monomer component having low volatility, and therefore, when inkjet printing is performed, the continuous ejection property or the re-ejection property is good, and the fine microlens shape and the protective film pattern after printing can be maintained. Therefore, when the photocurable inkjet ink of the present invention is used, integration of fine patterns can be performed, and thus a small-sized and high-performance electronic component can be preferably manufactured. Particularly, the method is preferably used for manufacturing a fine microlens and a high-definition protective film.

Detailed Description

The present invention will be specifically described below.

< 1. Photocurable ink jet ink >

The present invention relates to a photocurable inkjet ink which contains a polyfunctional (meth) acrylate (A), a monofunctional (meth) acrylate (B) having a low volatility, and a photopolymerization initiator (C), and has a viscosity of 1 to 100 mPas at 25 ℃.

The photocurable inkjet ink of the present invention is preferably colorless and transparent because it is used for electronic parts requiring an optical function. However, the optical function of the obtained cured film is not limited to this, as long as it does not significantly deteriorate or adversely affect the electronic components mounted thereon.

the photocurable inkjet ink of the present invention may optionally contain a compound having another radically polymerizable double bond, a solvent, a polymerization inhibitor, a flame retardant, an ultraviolet absorber, a photostabilizer, an antioxidant, an antistatic agent, a surfactant, and the like. The "compound having another radically polymerizable double bond" is a compound having a radically polymerizable double bond other than the polyfunctional (meth) acrylate (a) and the monofunctional (meth) acrylate (B) having low volatility.

(meth) acrylic acid esters

In the present specification, "(meth) acrylate" is used to indicate both or either of acrylate and methacrylate.

In the hardening reaction of the (meth) acrylate, since the double bond of the (meth) acryloyl group is radical-polymerized, the "functional" moiety means one (meth) acryloyl group, and the monofunctional means two or more (meth) acryloyl groups.

The above components are explained below.

1.1.1. Polyfunctional (meth) acrylate (A)

The polyfunctional (meth) acrylate (a) of the present invention is not particularly limited as long as it is a compound having the above structure, but is preferably a structure of formula (1) or formula (3). By using the polyfunctional (meth) acrylate (a) of the present invention, the curing properties of the photo-curable ink become good.

[ solution 3]

In the formula (1), R¹Is hydrogen, C1-C6 alkyl or hydroxymethyl, R²、R³And R⁴Each independently is hydrogen or methyl, R⁵、R⁶、R⁷And R⁸Each independently an alkylene group having 1 to 6 carbon atoms, k is 0 or 1, and l, m and n are each independently an integer of 0 to 10.

in the formula (3), R¹³And R¹⁴Each independently is hydrogen or methyl, R¹⁵and R¹⁶Each independently an alkylene group having 1 to 6 carbon atoms, R¹⁷Is a divalent organic radical or a single bond, R¹⁸And R¹⁹Are each independently-O-or a single bond. Wherein, in R¹⁷In the case of a single bond, R¹⁸And R¹⁹Either is-O-or both are single bonds. c and d are each independently an integer of 0 to 10.

For example, at R¹⁷In the case of a single bond, R¹⁸And R¹⁹Directly form a bond to form (-R)¹⁸-R¹⁹-)。

In the formula (1), k is 0 or 1, and l + m + n is preferably 0.

Specific examples of the compound having the structure of formula (1) include: glycerol tri (meth) acrylate, trimethylolethane tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, Ethylene Oxide (EO) -modified glycerol tri (meth) acrylate, Propylene Oxide (PO) -modified glycerol tri (meth) acrylate, trimethylolpropane EO-modified tri (meth) acrylate, trimethylolpropane PO-modified tri (meth) acrylate, pentaerythritol EO-modified tri (meth) acrylate, pentaerythritol PO-modified tri (meth) acrylate, and the like.

In the formula (3), R is preferably R from the viewpoint of compatibility with ink¹⁵And R¹⁶Each of which is an alkylene group having 2 carbon atoms, and further, from the viewpoint of adhesion to a substrate, c and d are particularly preferably 2. As a constituent R¹⁷The divalent organic group (b) has a linear or cyclic alkylene structure or phenylene structure having 1 to 20 carbon atoms, and is exemplified by a heterocyclic structure such as an isocyanurate structure.

Specific examples of the compound having the structure of formula (3) include: tricyclodecane di (meth) acrylate, tricyclodecane dimethanol di (meth) acrylate, bisphenol AEO-modified di (meth) acrylate, bisphenol F EO-modified di (meth) acrylate, tris (2-hydroxyethyl) isocyanurate di (meth) acrylate, trimethylolpropane di (meth) acrylate, pentaerythritol di (meth) acrylate, ethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, polytetramethylene glycol diacrylate, polyethylene glycol di (meth) acrylate, propylene glycol diacrylate, dipropylene glycol diacrylate, polypropylene glycol diacrylate, butanediol di (meth) acrylate, dibutylene glycol di (meth) acrylate, polytetramethylene glycol di (meth) acrylate, 1, 4-butanediol di (meth) acrylate, and mixtures thereof, 1, 6-hexanediol di (meth) acrylate, 1, 9-nonanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, and the like.

Further, "EO modification" means ethylene oxide modification, "PO modification" means propylene oxide modification, and the number of moles in parentheses indicates the amount of ethylene oxide or propylene oxide added per molecule.

Among these, pentaerythritol tri (meth) acrylate is particularly preferable in terms of excellent photocurability and easiness in adjustment of a preferable viscosity range as an ink for inkjet. In addition, from the viewpoint of compatibility with ink and adhesion to a substrate, bisphenol a EO-modified diacrylate and bisphenol F EO-modified diacrylate are preferable, and particularly from the viewpoint of adhesion to an inorganic substrate, bisphenol F EO-modified diacrylate is preferable.

These polyfunctional (meth) acrylates (A) may be one compound or a mixture of two or more different compounds.

When the content of the polyfunctional (meth) acrylate (a) is 10 to 75 wt% based on the total amount of the photocurable inkjet ink of the present invention, the viscosity is preferably adjusted to be suitable for the application, and in consideration of balance with other characteristics, the content is more preferably 15 to 70 wt%, and still more preferably 20 to 65 wt% (wherein the total of (a) to (C) is not more than 100 wt%).

1.1.2. Low volatility monofunctional (meth) acrylates (B)

The low-volatility monofunctional (meth) acrylate (B) of the present invention is not particularly limited as long as it has a non-volatility of 75% or more and a viscosity of 1 to 70 mPas (25 ℃ C.) in evaluation method 1. By using the low-volatility monofunctional (meth) acrylate (B) of the present invention, volatilization of the photocurable ink can be suppressed.

[ evaluation method 1]

With a monofunctional (meth) acrylate (B): pentaerythritol tetra (tri) acrylate 25: 45 by weight ratio, to prepare an evaluation solution. Pentaerythritol tetra (tri) acrylate is a mixture of pentaerythritol tetraacrylate and pentaerythritol triacrylate, for example, M305, manufactured by east asian synthesis (japan).

The mixture of pentaerythritol triacrylate and pentaerythritol tetraacrylate is pentaerythritol triacrylate: pentaerythritol tetraacrylate ═ (55 to 63): (37-45) in a weight ratio of monofunctional (meth) acrylate (B) to the mixture of monofunctional (meth) acrylate (B): mixture 25: 45 by weight ratio.

(1) The weight of the glass substrate 5cm × 5cm was measured.

(2) The evaluation liquid was dropped on the glass substrate of (1) and applied by spin coating so that the application weight became an error of 25 mg. + -.2 mg.

(3) The weight of the glass substrate coated with the evaluation solution of (2) was measured.

(4) The weight of (1) was subtracted from the weight of (3) to calculate the coating weight of the evaluation liquid.

(5) The glass substrate coated with the evaluation liquid of (3) was heated on a hot plate at 50 ℃ for 15 minutes.

(6) The weight of the heated glass substrate in (5) was measured, and the weight in (1) was subtracted to calculate the remaining amount of the evaluation liquid.

(7) The non-volatility was calculated according to the following calculation formula.

Non-volatility% + balance ÷ coating weight × 100

Specific examples of the compound include: 4-hydroxybutyl (meth) acrylate, tetrahydrofurfuryl alcohol acrylic acid polymer ester, and the compound represented by formula (2).

[ solution 4]

(in the formula, R⁹Is hydrogen or methyl, R¹⁰And R¹¹Each independently hydrogen or methyl, a is an integer of 1 to 10, b is 0 or 1, R¹²Is hydrogen or C1-11 alkyl. )

Among them, compounds having a structure represented by formula (2) are preferable in terms of low volatility and easy adjustment of a preferable viscosity range as an ink jet ink, and 2-ethyleneoxyethyl (meth) acrylate and 2- (2-ethyleneoxyethoxy) ethyl (meth) acrylate are particularly preferable.

These low-volatility monofunctional (meth) acrylates (B) may be one compound or a mixture of two or more different compounds.

When the content of the low-volatility monofunctional (meth) acrylate (B) is 20 to 90 wt%, and further 20 to 89 wt% of the total amount of the photocurable inkjet ink of the present invention, the viscosity is preferably adjusted to a viscosity suitable for the application, and in consideration of balance with other characteristics, the content is more preferably 25 to 85 wt%, and further preferably 30 to 80 wt% (wherein the total of (a) to (C) is not more than 100 wt%).

1.1.3. Compounds having other radically polymerizable double bonds

The photo-curable ink-jet ink of the present invention may contain a compound having another radically polymerizable double bond within a range not impairing photo-curing properties, adhesion, transmittance and strength.

The compound having another radical polymerizable double bond includes resins having a radical polymerizable unsaturated bond such as a polyfunctional (meth) acrylate (a), a (meth) acrylate monomer other than a monofunctional (meth) acrylate (B) having low volatility, a low molecular weight compound having a radical polymerizable double bond other than a (meth) acrylate, an unsaturated polyester resin, a polyester (meth) acrylate resin, an epoxy (meth) acrylate resin, and a urethane (meth) acrylate resin.

As the (meth) acrylate ester monomer, there may be mentioned: methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, 2- (2-ethoxyethoxy) ethyl acrylate, methoxypolyethylene glycol acrylate, polyalkylene glycol acrylate, ditrimethylolpropane tetra (meth) acrylate, pentaerythritol diacrylate monostearate, pentaerythritol tetra (meth) acrylate, dipentaerythritol diacrylate, dipentaerythritol tri (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, epsilon-caprolactone addition trimethylolpropane tri (meth) acrylate, poly (ethylene glycol, Di-trimethylolpropane tetra (meth) acrylate added with epsilon-caprolactone, pentaerythritol tetra (meth) acrylate added with epsilon-caprolactone, dipentaerythritol hexa (meth) acrylate added with epsilon-caprolactone, and the like.

Specific examples of the low-molecular weight compound having a radical polymerizable double bond other than the (meth) acrylate include: crotonic acid, alpha-chloroacrylic acid, cinnamic acid, maleic acid, fumaric acid, N-vinylformamide, 2-allyloxymethyl methacrylate, polymethyl methacrylate macromonomer, N-cyclohexylmaleimide, N-phenylmaleimide, styrene, (meth) acrylamide, N-dimethyl (meth) acrylamide, N-diethyl (meth) acrylamide, N-dimethylaminopropyl (meth) acrylamide, N-isopropyl (meth) acrylamide, and N-hydroxyethyl (meth) acrylamide.

Examples of the unsaturated polyester resin include those obtained by dissolving a condensation product (unsaturated polyester) obtained by esterification of a polyhydric alcohol and an unsaturated polybasic acid (and optionally a saturated polybasic acid) in a polymerizable monomer. The unsaturated polyester can be produced by polycondensation of an unsaturated acid such as maleic anhydride and a diol such as ethylene glycol. Specifically, there can be mentioned a method comprising reacting a polybasic acid having a polymerizable unsaturated bond such as fumaric acid, maleic acid or itaconic acid or an anhydride thereof as an acid component with a polyhydric alcohol such as ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, 1, 2-butanediol, 1, 3-butanediol, 1, 5-pentanediol, 1, 6-hexanediol, 2-methyl-1, 3-propanediol, 2-dimethyl-1, 3-propanediol, cyclohexane-1, 4-dimethanol, an ethylene oxide adduct of bisphenol A or a propylene oxide adduct of bisphenol A as an alcohol component, further, a polybasic acid containing no polymerizable unsaturated bond such as phthalic acid, isophthalic acid, terephthalic acid, tetrahydrophthalic acid, adipic acid, sebacic acid, or an anhydride thereof is added as an acid component as necessary.

As the polyester (meth) acrylate resin, there may be mentioned: (1) the acrylic resin composition is obtained by (1) reacting an epoxy compound containing an α, β -unsaturated carboxylic acid ester group with a polyester having a terminal carboxyl group obtained by reacting a saturated polybasic acid and/or an unsaturated polybasic acid with a polyhydric alcohol, (2) reacting a (meth) acrylate obtained by reacting a hydroxyl group-containing acrylate with a polyester having a terminal carboxyl group obtained by reacting a saturated polybasic acid and/or an unsaturated polybasic acid with a polyhydric alcohol, (3) reacting a (meth) acrylic acid with a polyester having a terminal hydroxyl group obtained by reacting a saturated polybasic acid and/or an unsaturated polybasic acid with a polyhydric alcohol.

Examples of the saturated polybasic acid usable as a raw material of the polyester (meth) acrylate include polybasic acids having no polymerizable unsaturated bond such as phthalic acid, isophthalic acid, terephthalic acid, tetrahydrophthalic acid, adipic acid, and sebacic acid, anhydrides thereof, and polymerizable unsaturated polybasic acids such as fumaric acid, maleic acid, and itaconic acid, and anhydrides thereof. Further, the polyol component is the same as the unsaturated polyester.

The epoxy (meth) acrylate resin is a compound (vinyl ester) having a polymerizable unsaturated bond, which is generated by a ring-opening reaction of a compound having a glycidyl group (epoxy group) and a carboxyl group of a carboxyl compound having a polymerizable unsaturated bond such as (meth) acrylic acid. A compound which is usually dissolved in a polymerizable monomer is used.

The vinyl ester is produced by a known method, and examples of the compound having a glycidyl (epoxy) group include epoxy (meth) acrylates obtained by reacting an epoxy resin with an unsaturated monobasic acid such as acrylic acid or methacrylic acid.

Flexibility can also be imparted by reacting various epoxy resins with a bisphenol (e.g., type a) or a dibasic acid such as adipic acid, sebacic acid, dimer acid (halidum 270S: halimasa (haima)) or the like.

Examples of the compound having an epoxy resin glycidyl group (epoxy group) as a raw material include bisphenol a diglycidyl ether and its high molecular weight homologues, novolak-type glycidyl ethers, and the like. Compounds which, in addition to (meth) acrylic acid, comprise reactants of diphenols, for example of type A, or of diacids, adipic acid, sebacic acid, dimer acid (Haridimer 270S: Harima (Harima) conversion (Strand)), etc.

Examples of the urethane (meth) acrylate resin include a radically polymerizable unsaturated group-containing oligomer obtainable by: after the polyisocyanate is reacted with the polyol or the polyol, the hydroxyl group-containing (meth) acrylic compound and, if necessary, the hydroxyl group-containing allyl ether compound are further reacted.

Specific examples of the polyisocyanate include: 2, 4-tolylene diisocyanate and isomers thereof, diphenylmethane diisocyanate, hexamethylene diisocyanate, hydrogenated xylylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, dicyclohexylmethane diisocyanate, naphthalene diisocyanate, triphenylmethane triisocyanate, Bannacoke (Bannock) D-750, Corison (Crisvon) NK (trade name; manufactured by Dajapan ink chemical industry (stock)), Desmodur (Desmodur) L (trade name; manufactured by Sumitomo Bayer polyurethane (stock)), Colonet (Coronate) L (trade name; manufactured by Japan polyurethane industry (stock)), Takenet (Takenate) D102 (trade name; manufactured by Mitsui Wuta chemical (stock)), Itemter (Isonate)143L (trade name; manufactured by Mitsui chemical (stock)), and the like.

The polyol includes polyester polyol, polyether polyol and the like, and specifically includes: glycerin-ethylene oxide adduct, glycerin-propylene oxide adduct, glycerin tetrahydrofuran adduct, glycerin ethylene oxide-propylene oxide adduct, trimethylolpropane-ethylene oxide adduct, trimethylolpropane-propylene oxide adduct, trimethylolpropane-tetrahydrofuran adduct, trimethylolpropane-ethylene oxide propylene oxide adduct, dipentaerythritol-ethylene oxide adduct, dipentaerythritol-propylene oxide adduct, dipentaerythritol-tetrahydrofuran adduct, dipentaerythritol-ethylene oxide propylene oxide adduct, and the like.

Specific examples of the polyhydric alcohols include: ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, polypropylene glycol, 2-methyl-1, 3-propanediol, 1, 3-butanediol, an adduct of bisphenol a with propylene oxide or ethylene oxide, 1,2,3, 4-tetrahydroxybutane, glycerol, trimethylolpropane, 1, 3-butanediol, 1, 2-cyclohexanediol, 1, 3-cyclohexanediol, 1, 4-cyclohexanediol, p-xylylene glycol, dicyclohexyl-4, 4-diol, 2, 6-decahydronaphthalene glycol (2, 6-decahydronaphthalene glycol), 2, 7-decahydronaphthalene glycol, and the like.

The hydroxyl group-containing (meth) acrylic compound is not particularly limited, and is preferably a hydroxyl group-containing (meth) acrylate, and specific examples thereof include: 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxybutyl (meth) acrylate, polyethylene glycol mono (meth) acrylate, polypropylene glycol mono (meth) acrylate, di (meth) acrylate of tris (hydroxyethyl) isocyanuric acid, pentaerythritol tri (meth) acrylate, and the like.

The compound having another radically polymerizable double bond may be one kind or a mixture of two or more kinds. The content of the compound having another radical polymerizable double bond is preferably 20 wt% or less of the total amount of the photocurable inkjet ink of the present invention, in consideration of balance with other characteristics.

1.2. Photopolymerization initiator (C)

The photocurable inkjet ink of the present invention contains a photopolymerization initiator (C). The photopolymerization initiator (C) is not particularly limited as long as it is a compound that can generate radicals by irradiation with ultraviolet light or visible light.

Specific examples of the photopolymerization initiator (C) include: benzophenone, michaelis ketone, 4 '-bis (diethylamino) benzophenone, xanthone, thioxanthone, isopropyl xanthone, 2, 4-diethylthioxanthone, 2-ethylanthraquinone, acetophenone, 2-hydroxy-2-methylpropiophenone, 2-hydroxy-2-methyl-4' -isopropylphenylacetone, 1-hydroxycyclohexylphenylketone, isopropyl benzoin ether, isobutyl benzoin ether, 2-diethoxyacetophenone, 2-dimethoxy-2-phenylacetophenone, camphorquinone, benzanthrone, 2-methyl-1- [4- (methylthio) phenyl ] propanone]-2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1, ethyl 4-dimethylaminobenzoate, isoamyl 4-dimethylaminobenzoate4,4' -di (tert-butylperoxycarbonyl) benzophenone, 3,4,4' -tri (tert-butylperoxycarbonyl) benzophenone, 3',4,4' -tetra (tert-hexylperoxycarbonyl) benzophenone, 3' -di (methoxycarbonyl) -4,4' -di (tert-butylperoxycarbonyl) benzophenone, 3,4' -di (methoxycarbonyl) -4,3' -di (tert-butylperoxycarbonyl) benzophenone, 4,4' -di (methoxycarbonyl) -3,3' -di (tert-butylperoxycarbonyl) benzophenone, 2- (4' -methoxystyryl) -4, 6-bis (trichloromethyl) -s-triazine, 2- (3',4' -dimethoxystyryl) -4, 6-bis (trichloromethyl) -s-triazine, 2- (2 '-methoxystyryl) -4, 6-bis (trichloromethyl) -s-triazine, 2- (4' -pentyloxypyryl) -4, 6-bis (trichloromethyl) -s-triazine, 4- [ p-N, N-bis (ethoxycarbonylmethyl)]-2, 6-bis (trichloromethyl) -s-triazine, 1, 3-bis (trichloromethyl) -5- (2' -chlorophenyl) -s-triazine, 1, 3-bis (trichloromethyl) -5- (4' -methoxyphenyl) -s-triazine, 2- (p-dimethylaminostyryl) benzoxazole, 2- (p-dimethylaminostyryl) benzothiazole, 2-mercaptobenzothiazole, 3' -carbonylbis (7-diethylaminocoumarin), 2- (o-chlorophenyl) -4,4',5,5' -tetraphenyl-1, 2' -biimidazole, 2' -bis (2-chlorophenyl) -4,4',5,5' -tetrakis (4-ethoxycarbonylphenyl) -1,2' -biimidazole, 2' -bis (2, 4-dichlorophenyl) -4,4',5,5' -tetraphenyl-1, 2' -biimidazole, 2' -bis (2, 4-dibromophenyl) -4,4',5,5' -tetraphenyl-1, 2' -biimidazole, 2' -bis (2,4, 6-trichlorophenyl) -4,4',5,5 '-tetraphenyl-1, 2' -biimidazole, 3- (2-methyl-2-dimethylaminopropionyl) carbazole, 3, 6-bis (2-methyl-2-morpholinopropionyl) -9-n-dodecylcarbazole, 1-hydroxycyclohexylphenylketone, bis (. eta.).⁵-2, 4-cyclopentadien-1-yl) -bis (2, 6-difluoro-3- (1H-pyrrol-1-yl) -phenyl) titanium, 2- (dimethylamino) -2- [ (4-methylphenyl) methyl]-1- [4- (4-morpholinyl) phenyl]1-butanone, bis (2,4, 6-trimethylbenzoyl) phenylphosphine oxide and 2,4, 6-trimethylbenzoyl diphenylphosphine oxide.

The photopolymerization initiator (C) may be one kind or a mixture of two or more kinds.

The content of the photopolymerization initiator (C) is preferably 2 to 15% by weight, more preferably 3 to 10% by weight because photocurability with respect to ultraviolet rays is excellent when the content is 1 to 20% by weight of the total amount of the photocurable ink of the present invention.

1.3. Solvent

The photocurable inkjet ink of the present invention may also contain a solvent. Examples of the solvent usable in the present invention include: diethyl ether, tetrahydrofuran, diphenyl ether, dimethoxybenzene, acetone, methanol, ethanol, isopropanol, butanol, tert-butanol, benzyl alcohol, methyl ethyl ketone, methyl isobutyl ketone, acetonitrile, propionitrile, benzonitrile, ethylene carbonate, propylene carbonate, ethyl acetate, isobutyl acetate, butyl propionate, ethyl lactate, methyl oxyacetate, ethyl oxyacetate, butyl oxyacetate, methyl methoxyacetate, ethyl methoxyacetate, butyl methoxyacetate, methyl ethoxyacetate, ethyl ethoxyacetate, methyl 3-oxopropionate, ethyl 3-oxopropionate, methyl 3-methoxypropionate, ethyl 3-methoxypropionate, methyl 3-ethoxypropionate, ethyl 3-ethoxypropionate, methyl 2-oxopropionate, ethyl 2-oxopropionate, propyl 3-oxopropionate, methyl isopropoxide, ethyl 2-oxopropionate, methyl n-propyl 2-oxopropionate, methyl isopropoxide, ethyl acetate, ethyl isopropoxide, methyl acetate, ethyl acetate, n, Methyl 2-methoxypropionate, ethyl 2-methoxypropionate, propyl 2-methoxypropionate, methyl 2-ethoxypropionate, ethyl 2-ethoxypropionate, methyl 2-oxo-2-methylpropionate, ethyl 2-oxo-2-methylpropionate, methyl 2-methoxy-2-methylpropionate, ethyl 2-ethoxy-2-methylpropionate, methyl pyruvate, ethyl pyruvate, propyl pyruvate, methyl acetoacetate, ethyl acetoacetate, methyl 2-oxobutyrate, ethyl 2-oxobutyrate, methyl 2-hydroxyisobutyrate, dioxane, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, 1, 4-butanediol, propylene glycol, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate, dipropylene glycol monoethyl ether acetate, dipropylene glycol monobutyl ether acetate, ethylene glycol monobutyl ether acetate, cyclohexanone, cyclopentanone, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol ethyl methyl ether, tetraethylene glycol dimethyl ether, toluene, xylene, anisole, gamma-butyrolactone, N, n-dimethylacetamide, N-dimethylformamide, N-methyl-2-pyrrolidone, and dimethylimidazolidinone.

The solvent that can be used in the photocurable inkjet ink of the present invention may be one kind or a mixture of two or more kinds.

In the ink of the present invention, it is preferable that the content of the solvent is 0 to 60 wt% based on 100 wt% of the total amount of the ink (in terms of solid content), because the ejection hole of the inkjet head is less likely to be clogged when the ink is applied by the inkjet method. In view of balance with other characteristics, the amount is more preferably 0 to 40% by weight, and still more preferably 0 to 20% by weight.

1.4. Polymerization inhibitor

The photocurable inkjet ink of the present invention may contain a polymerization inhibitor in order to improve storage stability. Specific examples of the polymerization inhibitor include: 4-methoxyphenol, hydroquinone and phenothiazine. Among these, phenothiazine is preferable because the increase in viscosity is small even when stored for a long period of time.

The polymerization inhibitor that can be used in the photocurable inkjet ink of the present invention may be one kind or a mixture of two or more kinds.

When the content of the polymerization inhibitor is 1 wt% or less of the total amount of the inkjet ink of the present invention, the increase in viscosity is small even during long-term storage, and therefore, it is preferably 0.5 wt% or less, and more preferably 0.1 wt% or less, in view of balance with other characteristics.

1.5. Flame retardant

The photocurable inkjet ink of the present invention may also contain a flame retardant. The flame retardant is preferably contained because the resulting cured film has high flame retardancy. The flame retardant is not particularly limited as long as it is a compound capable of imparting flame retardancy, but it is preferable to use an organic phosphorus flame retardant from the viewpoint of low toxicity, low pollution, and safety.

Examples of the organic phosphorus flame retardant include: triphenyl phosphate, tricresyl phosphate, trixylenyl phosphate, cresyl phenyl phosphate, 2-ethylhexyl diphenyl phosphate, 9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10 oxide, 10- (2, 5-dihydroxyphenyl) -10H-9-oxa-10-phosphaphenanthrene-10 oxide, condensed 9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10 oxide, and the like.

The content of the flame retardant is not particularly limited, and is preferably 40% by weight or less of the total amount of the photocurable inkjet ink of the present invention, in consideration of balance with other characteristics.

1.6. Ultraviolet absorber and light stabilizer

The photocurable inkjet ink of the present invention may contain an ultraviolet absorber and a Light Stabilizer (Hindered Amine Light Stabilizer, HALS)) in order to prevent deterioration of the cured film or the like obtained by Light such as backlight.

Examples of the ultraviolet absorber include: 2- (5-methyl-2-hydroxyphenyl) benzotriazole, 2- (3, 5-di-tert-butyl-2-hydroxyphenyl) -5-chlorobenzotriazole, benzotriazole compounds such as 2- (3, 5-di-tert-amyl-2-hydroxyphenyl) benzotriazole, triazine compounds such as 2- (4, 6-diphenyl-1, 3, 5-triazin-2-yl) -5- [ (hexyl) oxy ] -phenol, benzophenone compounds such as 2-hydroxy-4-n-octyloxybenzophenone, and oxalic acid aniline compounds such as 2-ethoxy-2' -ethyloxalic acid dianiline.

Examples of light stabilizers (HALS) include: denumbin (TINUVIN) (registered trademark) 5100, Denumbin (TINUVIN)292 (compound name: bis (1,2,2,6, 6-pentamethyl-4-piperidinyl) sebacate, methyl (1,2,2,6, 6-pentamethyl-4-piperidinyl) sebacate), Denumbin (TINUVIN)152 (compound name: 2, 4-bis [ N-butyl-N- (1-cyclohexyloxy-2, 2,6, 6-tetramethylpiperidin-4-yl) amino ] -6- (2-hydroxyethylamine) -1,3, 5-triazine), Denumbin (TINUVIN)144 (compound name: bis (1,2,2,6, 6-pentamethyl-4-piperidinyl) - [ [3, 5-bis (1, 1-dimethylethyl) -4-hydroxyphenyl ] methyl ] butyl malonate), monardan (TINUVIN)123 (compound name: the reaction product of decanedioic acid, bis (2,2,6, 6-tetramethyl-1- (octyloxy) -4-piperidyl) ester (in the presence of 1, 1-dimethylethyl hydroperoxide and octane)), merin (TINUVIN)111FDL (about 50% of merin (TINUVIN)622, compound name: (succinic acid polymer (4-hydroxy-2, 2,6, 6-tetramethylpiperidinyl-yl) ethanol), about 50% of smartweed (CHIMASSORB)119, compound name: N-N '-N' -tetrakis (4, 6-bis (butyl- (N-methyl-2, 2,6, 6-tetramethylpiperidin-4-yl) amino) triazin-2-yl) -4, 7-diazadene-1, 10-diamine) (both manufactured by BASF corporation) or Addisco-stap (Adk tab) (manufactured by Adeka corporation) LA series, specifically LA-52, LA-57, LA-62, LA-67, and the like.

The ultraviolet absorber and the light stabilizer that can be used in the photocurable inkjet ink of the present invention may be one compound or a mixture of two or more compounds.

The content of the ultraviolet absorber and the light stabilizer is not particularly limited, and is preferably 5% by weight or less of the total amount of the photocurable inkjet ink of the present invention, in consideration of balance with other characteristics.

1.7. Antioxidant agent

The photocurable inkjet ink of the present invention may contain an antioxidant in order to prevent oxidation of the cured film or the like obtained.

As the antioxidant, there may be mentioned: pentaerythritol tetrakis [3- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate ], triethylene glycol-bis- [3- (3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate ], 1, 6-hexanediol-bis [3- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate ], octadecyl-3- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate, hindered phenol compounds such as diethyl 3, 5-di-tert-butyl-4-hydroxybenzyl phosphate, n-butylamine, amine compounds such as triethylamine and diethylaminomethyl methacrylate, (dilauryl-3, 3' -thiodipropionate, di-tert-butyl-4-hydroxyphenyl) propionate, and the like, Dimyristyl-3, 3 '-thiodipropionate, distearyl-3, 3' -thiodipropionate, etc.), triphenyl ] phosphite, diphenylisodecyl phosphite, phenyldiisodecyl phosphite, tris (nonylphenyl) phosphite, diisodecyl pentaerythritol phosphite, tris (2, 4-di-tert-butylphenyl) phosphite, cycloneopentane-tetraylbis (octadecyl) phosphite, cycloneopentane-tetraylbis (2, 4-di-tert-butylphenyl) phosphite, cycloneopentane-tetraylbis (2, 4-di-tert-butyl-4-methylphenyl) phosphite, bis [ 2-tert-butyl-6-methyl-4- {2- (octadecyloxycarbonyl) ethyl } phenyl ] hydrogen phosphite, etc. ], and the like, And phosphorus compounds such as oxaphosphaphenanthrene oxides (9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 10- (3, 5-di-tert-butyl-4-hydroxybenzyl) -9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, and 10-decyloxy-9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide).

The antioxidant that can be used in the photocurable inkjet ink of the present invention may be a single compound or a mixture of two or more compounds.

The content of the antioxidant is not particularly limited, and is preferably 5% by weight or less of the total amount of the photocurable inkjet ink of the present invention, in consideration of balance with other characteristics.

1.8. Antistatic agent

The photocurable inkjet ink of the present invention may also contain an antistatic agent. The antistatic agent prevents the surface of the obtained cured film from being electrostatically charged and prevents dust and the like from adhering to the surface.

The antistatic agent is not particularly limited, and may be any antistatic agent known to those skilled in the art, such as ethoxylated glycerin fatty acid ester, quaternary amine compound, aliphatic amine derivative, alkyl sulfonate compound, epoxy resin (such as polyethylene oxide), siloxane, poly (ethylene glycol) ester, and other alcohol derivative (such as poly (ethylene glycol) ether).

Specific examples of the antistatic agent include: colket (COLCOAT)200, Colket (COLCOAT)515, Colket (COLCOAT)1000, Colket (COLCOAT) WAS-15X (both of Colket (COLCOAT) (Strand)), Elekeribo (Electoriter) AC, Elekeribo (Electorstriper) QN, Elekeribo (Electorstriper) ME-2 (both of Strand), FC-4400 (3M), AC-ILA (Strand), IL-A2, IL-AP3 (both of Guangrong chemical industry (Strand)), PEL-20A, PEL-25, PEL-1090, PEL-100, CIL-1060, CIL-313 (both of Japanese Carlite (Japanlite) (Strand), Elekett 1-SX 1, SX 1-3000 (SX-SX 1-3000), Ehrlichter (SX-1-SX) (Strand SX-1 (SX-SX) (Strand SX-3000 (SX-1, SX-SX) (Strand SX-1, SX-3000) (Strand SX-SX) manufactured by Karl, SX (SX-K, SX, disparon 1121 (manufactured by nanba chen chemical synthesis (stock)), PC-3662, PC-6862 (manufactured by pilaf oil chemical industry (stock)), and the like.

The antistatic agent that can be used in the photocurable inkjet ink of the present invention may be one kind of compound or a mixture of two or more kinds of compounds.

The content of the antistatic agent is not particularly limited, and is preferably 10% by weight or less of the total amount of the photocurable inkjet ink of the present invention, in consideration of balance with other characteristics.

1.9. Surface active agent

The photocurable inkjet ink of the present invention may further contain a surfactant as needed for the purpose of controlling the applicability to an optical sheet.

Specific examples of the surfactant include: perlipalo (Polyflow) No.45, Perlipalo (Polyflow) KL-245, Perlipalo (Polyflow) No.75, Perlipalo (Polyflow) No.90, Perlipalo (Polyflow) No.95 (trade name, manufactured by Co., Ltd.) chemical industry (Ltd.), Diperbyk (Disperbyk)161, Diperbyk (Disperbyk)162, Diperbyk (Disperbyk)163, Diperbyk (Disperbyk)164, Diperbyk (Disperbyk)166, Diperbyk (Disperbyk)170, Diperbyk (Disperbyk)180, Diperbyk (Disperyk) 181, Diperbyk) 182, ByK 300, ByK 306, DiperbyK-368, Japan KF (KF) 310, KbByK-368, KyK-342, KbByK) 320, DiperbyK-320, Diperbyk (Disperbyk)170, Diperbyk (Byk) 150, Dipybk) 150, Dipyk (Byk) 150, Dipyk-K-150, Dipyk (EMByk) 342, Japan KF-K-310, Ky (KF-K-310, Ky) 180, Ky-K-180, Ky (Ky) 180, Ky-K-, KF-50-100CS (trade name, manufactured by shin-Etsu chemical industries, Ltd.), Sanflon (Surflon) SC-101, Sanflon (Surflon) KH-40 (trade name, manufactured by Qingmei chemical industries, Ltd.), Forgejt (Ftergent)222F, Forgejt (Ftergent)251, FTX-218 (trade name, manufactured by Neios (Neos), Thailand (TOGO Rad)2100, 2200N, 2250, 2600, 2700 (trade name, manufactured by Evonik Degussa) Inc.) TOP EF-351, TOP EF-352, EFTOPEF-601, EFTOP EF-801, EFTOP EF-802 (trade name, manufactured by Mitsubishi materials, manufactured by Egyo industries, Meijiafac) F-171, Meijiafac (Megafac) F-177, Meijia Fac (Megafac) F-444, Meigafac F-475, Meijia process (Megafac) F-556, Meijia process (Megafac) R-08, Meijia process (Megafac) R-30 (trade name, manufactured by Diesen (DIC)), fluoroalkyl benzenesulfonate, fluoroalkyl carboxylate, fluoroalkyl polyoxyethylene ether, fluoroalkyl ammonium iodide, fluoroalkyl betaine, fluoroalkyl sulfonate, perfluoroalkyl ethylene oxide adduct, diglycerin tetra (fluoroalkyl polyoxyethylene ether), fluoroalkyl trimethylammonium salt, fluoroalkyl sulfamate, polyoxyethylene nonylphenyl ether, polyoxyethylene octylphenyl ether, polyoxyethylene lauryl ether, polyoxyethylene oleyl ether, polyoxyethylene tridecyl ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, polyoxyethylene laurate, polyoxyethylene oleate, polyoxyethylene stearate, polyoxyethylene lauryl amine, sorbitan laurate, sorbitan palmitate, and mixtures thereof, Sorbitan stearate, sorbitan oleate, sorbitan fatty acid esters, polyoxyethylene sorbitan laurate, polyoxyethylene sorbitan palmitate, polyoxyethylene sorbitan stearate, polyoxyethylene sorbitan oleate, polyoxyethylene naphthyl ether, alkylbenzene sulfonate, and alkyl diphenyl ether disulfonate.

The surfactant that can be used in the photocurable inkjet ink of the present invention may be a single compound or a mixture of two or more compounds.

The content of the surfactant is preferably 2 wt% or less of the total amount of the photocurable inkjet ink of the present invention, because the coatability to the optical sheet can be effectively suppressed.

1.10. Ink for ink jet

1.10.1. Method for preparing ink for ink jet

The ink jet ink of the present invention can be prepared by mixing the respective components as raw materials by a known method.

In particular, the ink jet ink of the present invention is preferably prepared by mixing the components (a) to (D) and optionally other components, filtering the obtained solution, and degassing the filtered solution. The ink jet ink of the present invention prepared in the above manner is excellent in ejection property at the time of ink jet coating. For example, a fluororesin filter, a polyethylene filter, or a polypropylene filter can be used for the filtration.

1.10.2. Viscosity of ink for ink jet

the ink jet ink of the present invention has a viscosity at 25 ℃ of 1 to 200 mPas, preferably 2 to 150 mPas, and more preferably 3 to 100 mPas, as measured with an E-type viscometer. When the viscosity is the above-mentioned viscosity, the ink jet ink of the present invention can be applied by an ink jet method with good ejection performance by an ink jet apparatus.

The viscosity of the ink jet ink of the present invention at a temperature (preferably 25 to 120 ℃) when discharged from an ink jet apparatus is preferably 1 to 30mPa · s, more preferably 2 to 25mPa · s, and particularly preferably 3 to 20mPa · s.

When an ink jet ink having a viscosity of more than 30mPa · s at 25 ℃ is used, the viscosity of the ink jet ink at the time of ejection is lowered by heating the ink jet head, and more stable ejection can be realized. When the ink is ejected by heating, the viscosity of the ink jet ink at a heating temperature (preferably 40 to 120 ℃) is preferably 1 to 30 mPas, more preferably 2 to 25 mPas, and particularly preferably 3 to 20 mPas.

When the inkjet head is heated, it is preferable to use an inkjet ink containing no solvent.

1.10.3. Preservation of ink for ink jet

When the ink for ink jet of the present invention is stored at 4 to 25 ℃, the viscosity change during storage is small and the storage stability is good.

< 2. microlens and protective film >

The microlens or protective film of the present invention is formed from the ink of the present invention, and specifically, is preferably a microlens or protective film obtained by: after the ink of the present invention is applied to the surface of a substrate by an ink jet method, the ink is irradiated with light such as ultraviolet light or visible light and cured.

The microlens or the protective film of the present invention can be obtained by hardening the ink of the present invention, and therefore, is a microlens or a protective film having a good shape and good optical characteristics even after a constant temperature and humidity test.

The amount of light (exposure amount) irradiated when ultraviolet light or visible light is irradiated depends on the composition of the photocurable ink, but the wavelength is measured by UV-A (315 to 380nm), preferably 100mJ/cm, using an illuminometer (manufactured by UVpad-E, Arguo (ply))²～5,000mJ/cm²More preferably 100mJ/cm²～4,000mJ/cm²More preferably 100mJ/cm²～3,000mJ/cm². The wavelength of the ultraviolet light, the visible light, or the like to be irradiated is preferably 200nm to 500 nm.

The exposure machine is not particularly limited as long as it is a device that is equipped with a high-pressure mercury lamp, an ultrahigh-pressure mercury lamp, a metal halogen lamp, a halogen lamp, or the like and irradiates ultraviolet rays, visible rays, or the like in a range of 250nm to 500 nm.

The microlens or the protective film hardened by irradiation with light may be further heated and calcined as necessary, and the microlens or the protective film may be further hardened by heating and calcining at 80 to 250 ℃ for 10 to 60 minutes.

The "substrate" coated with the ink of the present invention is not particularly limited as long as it can be coated with the ink of the present invention, and the shape thereof is not limited to a flat plate shape, and may be a curved surface shape or the like.

The substrate is not particularly limited, and examples thereof include: a polyester resin substrate including polyethylene terephthalate (PET), polybutylene terephthalate (PBT), and the like; a polyolefin resin substrate containing polyethylene, polypropylene, and the like; organic polymer films including polyvinyl chloride, fluorine resins, acrylic resins, polyamides, polycarbonates, polyimides, and the like; a substrate comprising cellophane; a metal foil; a laminated film of polyimide and a metal foil; papers subjected to a filling treatment by cellophane, parchment, polyethylene, binder (clay binder), polyvinyl alcohol, starch, carboxymethyl cellulose (CMC), or the like having a filling effect; and a glass substrate.

As the substrate, a substrate containing additives such as an antioxidant, a deterioration inhibitor, a filler, an ultraviolet absorber, an antistatic agent, and/or an electromagnetic wave inhibitor in a range that does not adversely affect the effects of the present invention can be used. The substrate may be one having a surface treated, as necessary, by corona treatment, plasma treatment, spray treatment, or the like on at least a part of the surface of the substrate, or one having an easy-to-adhere layer, a protective film for a color filter, or a hard coat film provided on the surface.

The ink of the present invention can be used for the purpose of obtaining a microlens having a smaller diameter and a higher height, a protective film having a more highly brilliant pattern, or the like, and the surface of a substrate can be subjected to a liquid repellent treatment as required.

When the ink of the present invention is ejected onto a substrate, particularly an acrylic substrate, the surface state of the substrate is preferably uniform (partially extremely lyophilic, not liquid repellent). Therefore, it is preferable to perform surface treatment on the substrate surface in advance for the purpose of eliminating unevenness on the substrate surface.

The thickness of the substrate is not particularly limited, but is usually about 10 μm to 4mm, and can be suitably adjusted depending on the purpose of use, but is preferably 50 μm to 2mm, and more preferably 100 μm to 1 mm.

The ratio (H/D) of the lens height (H) to the lens diameter (D) of the microlens is not particularly limited as long as it is appropriately selected according to the intended use, and is preferably 0.15 or more, more preferably 0.16 or more, from the viewpoint of manufacturing an optical component or the like excellent in light extraction efficiency.

In the present invention, the "good-shaped microlens" refers to, for example, a microlens having a substantially circular shape (including a perfect circular shape) and having a ratio of a lens height to a lens diameter within the above range.

The light transmittance at a wavelength of 400nm in the photo-cured uniform film of 1 to 5 μm is preferably 98% or more, and more preferably 98.5% or more.

< 3. optical parts, electronic parts

The optical component of the present invention is not particularly limited as long as it has the microlens, and the microlens is preferably provided on a substrate.

Examples of the optical component include a light guide plate for a video display device, a lens base material for a 3D image display element, and the like.

The semiconductor package or flexible wiring board of the present invention is not particularly limited as long as it has the protective film, and the protective film is preferably provided on a substrate.

Examples of the electronic component include a wafer level package having a buffer layer, a rewiring insulating material, a barrier material, and an underfill material mounted thereon, and a flexible wiring board having a cover film mounted thereon.

< 4. device >

The device of the present invention includes the optical component and the electronic component.

Examples of the device include a display, an illumination device, and a 3D display device.

The Light guide plate is incorporated into a backlight, whereby, for example, a liquid crystal display for a liquid crystal display element can be manufactured, and an LED illumination can be realized by providing a configuration in which an LED Light source section incorporating a Light guide plate and a high-luminance Light Emitting Diode (LED) is provided at both ends of the Light guide plate.

by incorporating the lens base material into a display, an image is formed in a spatially floating manner, and thus a 3D display capable of displaying a stereoscopic image without wearing 3D glasses can be constructed.