JP2012144682A - Ultraviolet-curable inkjet ink composition, recorded matter and inkjet recording method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ultraviolet-curable inkjet ink composition excellent in curability, adhesion and storage stability, and to provide recorded matter and an inkjet recording method using the same.SOLUTION: The ultraviolet-curable inkjet ink composition includes a polymerizable compound and a photopolymerization initiator, wherein the polymerizable compound includes an N-vinyl group, a vinyl ether group and a (meth)acryloyl group as polymerizable groups. With respect to the polymerizable groups existing in the ink composition, the number ratio of the vinyl ether group to the N-vinyl group is (2-5)/1, and the number ratio of the (meth)acryloyl group to the vinyl ether group is (1.5-3.5)/1.

Description

  The present invention relates to an ultraviolet curable inkjet ink composition, a recorded matter, and an inkjet recording method.

  Conventionally, various methods have been used as a recording method for forming an image on a recording medium based on an image data signal. Among these, the ink jet system is an inexpensive apparatus, and ink is ejected only to a required image portion to form an image directly on a recording medium. Therefore, the ink can be used efficiently, and the running cost is low.

  In recent years, in order to form a good image such as water resistance, solvent resistance, and scratch resistance on the surface of a recording medium, an ultraviolet curable inkjet ink composition that cures when irradiated with ultraviolet rays in an inkjet recording method. Is used.

  On the other hand, in recent years, electronic parts (IC packages) formed by packaging semiconductor chips (integrated circuit (IC) chips) have been used in various devices, and such electronic parts include characters, symbols, logo marks, and the like. It is usual to carry out markings for printing etc. For this reason, there is a demand for a printing technique for applying markings suitable for electronic components.

  For example, Patent Document 1 discloses a marking method in which an ink attached to an electronic component such as an IC chip is irradiated with ultraviolet rays to fix the ink on the electronic component. Patent Document 2 discloses a marking method in which a lot number or the like is printed by an inkjet method on a discarded substrate portion at a peripheral portion of a substrate on which a large number of bare chips are taken.

  Further, for example, Patent Document 3 discloses an inkjet in printed wiring board manufacturing in which the integrated light quantity and illuminance of irradiated ultraviolet rays are in a specific range so that ink containing titanium dioxide is cured with a maximum ink film thickness of 10 to 30 μm. A recording method is disclosed. Patent Document 4 discloses a step of providing a marking by jetting an ultraviolet curable ink containing a colorant, a photopolymerization initiator, and an epoxy reagent onto a printed circuit board from an inkjet printer, and the marking is performed for at least 2 seconds. An inkjet printing method is disclosed that includes a step of subsequent exposure to ultraviolet light.

  Further, for example, Patent Document 5 discloses a molded IC package in which an IC package is coated and marked thereon. Patent Document 6 discloses a method for marking only a defective IC chip in a wafer having a plurality of IC chips.

JP 11-274335 A JP 2000-332376 A JP 2006-21479 A JP-T-2007-527459 Utility Model Registration No. 2539839 Specification JP 2003-273172 A

  However, all of the techniques disclosed in Patent Documents 1 to 6 are inferior to at least one of curability, adhesion, and storage stability, or have room for improvement. Therefore, the conventional marking method has a problem that it is difficult to apply it to a precise electronic component.

  Accordingly, it is an object of the present invention to provide an ultraviolet curable ink jet ink composition excellent in curability, adhesion, and storage stability, a recorded matter using the same, and an ink jet recording method. Moreover, not only marking on an IC package or the like, but also providing an ultraviolet curable inkjet ink composition excellent in curability, adhesion, and storage stability, and a recorded matter and an inkjet recording method using the same. Objective.

  The present inventors have intensively studied to solve the above problems. As a result, an ultraviolet curable inkjet ink composition containing a polymerizable compound having an N-vinyl group, a vinyl ether group, and a (meth) acryloyl group, and a photopolymerization initiator has good curability, adhesion, It was also found that storage stability may be exhibited.

  Therefore, the present inventors have further studied. Usually, a photopolymerization initiator breaks a bond between atoms by light irradiation to form a radical, which causes a radical polymerization reaction with the polymerizable compound, thereby polymerizing this polymerizable compound and proceeding polymerization (curing). It is something to be made. When the polymerizable compound contains an N-vinyl group, a vinyl ether group, and a (meth) acryloyl group as the polymerizable group (the case where each polymerizable group is present in the same molecule may be present in a different molecule). These polymerizable groups are easily cleaved by the action of the photopolymerization initiator in the above order, and the polymerization reaction proceeds with the cleavage. At that time, in the polymerizable compound, when the number ratio of the vinyl ether group to the N-vinyl group and the number ratio of the (meth) acryloyl group to the vinyl ether group are within a predetermined range, curability, adhesion, and storage stability are improved. The present invention was completed by finding out that both were excellent.

That is, the present invention is as follows.
[1]
An ultraviolet curable inkjet ink composition comprising a polymerizable compound and a photopolymerization initiator, wherein the polymerizable compound has N-vinyl group, vinyl ether group, (meth) acryloyl group as a polymerizable group, As the polymerizable group present in the ink composition, the number ratio of the vinyl ether groups is in the range of 2 to 5 with respect to one N-vinyl group, and ( The number ratio of the (meth) acryloyl group is in the range of 1.5 to 3.5 for one vinyl ether group, and the ultraviolet curable inkjet ink composition.
[2]
The number ratio of the N-vinyl group is in the range of 1.5 to 3.05 with respect to one photocleavage in the photopolymerization initiator, and the ultraviolet curable inkjet ink according to [1]. Composition.
[3]
The ultraviolet-curable ink jet ink composition according to [1] or [2], wherein the polymerizable compound includes N-vinylcaprolactam.
[4]
The polymerizable compound has the following general formula (I):
_{^{CH 2 = CR 1 -COOR 2 -O}} -CH = CH-R 3 ··· (I)
Wherein R ¹ is a hydrogen atom or a methyl group, R ² is a divalent organic residue having 2 to 20 carbon atoms, and R ³ is a hydrogen atom or a monovalent organic residue having 1 to 11 carbon atoms. Group.)
The ultraviolet curable ink-jet ink composition according to any one of [1] to [3], comprising a monomer represented by:
[5]
The ultraviolet curable inkjet ink composition according to [4], wherein the monomer is 2- (vinyloxyethoxy) ethyl acrylate.
[6]
The recording medium to which the ink composition adheres is an ultraviolet curable inkjet ink composition according to any one of [1] to [5], which is a package substrate or a semiconductor substrate.
[7]
Curing of the package base material or semiconductor base material as a recording medium, and the ultraviolet curable inkjet ink composition according to any one of [1] to [6] recorded on the package base material or the semiconductor base material A recorded matter comprising a thing.
[8]
[1] to [6] The ultraviolet ray curable ink composition for inkjet is ejected onto a recording medium, and the ejected ink composition emits light in a range of 350 nm to 400 nm. A curing step of curing the ink composition by irradiating with ultraviolet light having a peak wavelength.

  Hereinafter, embodiments for carrying out the present invention will be described in detail. In addition, this invention is not restrict | limited to the following embodiment, A various deformation | transformation can be implemented within the range of the summary.

  In the present specification, the “package base material” means a protective base material that encloses a semiconductor chip or the like. The “semiconductor base material” means a semiconductor chip or the like that includes a wafer that directly becomes a base material. Hereinafter, the package substrate or the semiconductor substrate is also referred to as “package substrate or the like”. The “recorded material” refers to a material in which a cured product is formed by recording ink on a package substrate or a semiconductor substrate. In addition, the hardened | cured material in this specification means the hardened | cured substance containing a cured film and a coating film.

  In this specification, “curability” refers to a property of curing in response to light. “Adhesiveness” refers to the property that the coating film is difficult to peel off from the substrate. In particular, in the embodiment, the property when a right-angled lattice pattern is cut into the cured product and penetrates to the substrate such as a package substrate. Say. “Storage stability” refers to the property that the viscosity is difficult to change before and after storage.

  In the present specification, “(meth) acrylate” means at least one of acrylate and its corresponding methacrylate, “(meth) acryloyl” means at least one of acryloyl and its corresponding methacryloyl, “(Meth) acryl” means at least one of acrylic and methacryl corresponding thereto.

[UV-curable inkjet ink composition]
One embodiment of the present invention relates to an ultraviolet curable inkjet ink composition (hereinafter also simply referred to as “ink composition”). The ink composition contains a polymerizable compound and a photopolymerization initiator, and the polymerizable compound contains an N-vinyl group, a vinyl ether group, and a (meth) acryloyl group as a polymerizable group, and As the polymerizable group present in the ink composition, the number ratio of vinyl ether groups to N-vinyl groups and the number ratio of (meth) acryloyl groups to vinyl ether groups are in the range of 2 to 5, respectively. It is in the range of 5-3.5.

  Hereinafter, additives (components) that are or can be included in the ink composition of the present embodiment will be described.

(Polymerizable compound)
The polymerizable compound contained in the ink composition of the present embodiment is polymerized at the time of light irradiation by the action of a photopolymerization initiator described later, and can cure the printed ink.
The polymerizable compound contains at least an N-vinyl group, a vinyl ether group, and a (meth) acryloyl group as a polymerizable group. One type of compound may be sufficient as the said polymeric compound, and it may consist of 2 or more types of compounds. When the polymerizable compound is a single compound, the compound contains all of N-vinyl group, vinyl ether group, and (meth) acryloyl group in the molecule. On the other hand, when the polymerizable compound is composed of two or more kinds of compounds, it is sufficient that all of these compounds contain all of N-vinyl group, vinyl ether group, and (meth) acryloyl group. May contain one or more groups selected from the group consisting of an N-vinyl group, a vinyl ether group, and a (meth) acryloyl group, and a polymerization that does not have any of these three groups An organic compound may be contained.

  The polymerizable compound in the present embodiment is characterized in that the number ratio of N-vinyl group, vinyl ether group, and (meth) acryloyl group is within a predetermined range as the polymerizable group present in the ink composition. And Specifically, the number ratio of vinyl ether groups is in the range of 2 to 5 and preferably in the range of 3 to 4 with respect to one N-vinyl group. The number ratio of (meth) acryloyl groups is in the range of 1.5 to 3.5 and preferably in the range of 2 to 2.5 with respect to one vinyl ether group. In this case, both the curability and storage stability of the ink composition, and the adhesion between the ink coating film and the recording medium are excellent. Hereinafter, specific examples of the polymerizable compound will be shown.

(Polymerizable compound having N-vinyl group)
The polymerizable compound having an N-vinyl group (CH ₂ ═CH—N) is a compound that contains an N-vinyl group and may contain at least one of a vinyl ether group and a (meth) acryloyl group. That is, in the present specification, the “polymerizable compound having an N-vinyl group” includes not only a polymerizable compound having only an N-vinyl group among N-vinyl group, vinyl ether group and (meth) acryloyl group, A polymerizable compound having only an N-vinyl group and a vinyl ether group, a polymerizable compound having only an N-vinyl group and a (meth) acryloyl group, and an N-vinyl group, a vinyl ether group and a (meth) acryloyl group Also includes polymerizable compounds. Examples of the polymerizable compound having an N-vinyl group include monofunctional, bifunctional, or polyfunctional (trifunctional or higher) N-vinyl compounds. Examples of the N-vinyl compound include, but are not limited to, N-vinylcaprolactam, N-vinylformamide, N-vinylcarbazole, N-vinylacetamide, N-vinylpyrrolidone, acryloylmorpholine, and derivatives thereof. Can be mentioned.

  Among these, N-vinylcaprolactam and N-vinylpyrrolidone are preferable in order to improve curability and adhesion.

  The said polymeric compound which has N-vinyl group may be used individually by 1 type, and may be used in combination of 2 or more type.

(Polymerizable compound having a vinyl ether group)
The polymerizable compound having a vinyl ether group (CH ₂ ═CH—O—) is a compound that may contain a vinyl ether group and a (meth) acryloyl group. That is, in this specification, the “polymerizable compound having a vinyl ether group” includes not only a polymerizable compound having only a vinyl ether group among N-vinyl group, vinyl ether group and (meth) acryloyl group, but also a vinyl ether group and N -Also includes polymerizable compounds having only vinyl groups, polymerizable compounds having only vinyl ether groups and (meth) acryloyl groups, and polymerizable compounds having vinyl ether groups, N-vinyl groups and (meth) acryloyl groups. To do.
Examples of the polymerizable compound having an N-vinyl group include monofunctional, bifunctional, or polyfunctional (trifunctional or higher) vinyl ether compounds. Examples of the vinyl ether compound include, but are not limited to, the following general formula (I):
^{_{CH 2 = CR 1 -COOR 2 -O}} -CH = CH-R 3 ··· (I)
Wherein R ¹ is a hydrogen atom or a methyl group, R ² is a divalent organic residue having 2 to 20 carbon atoms, and R ³ is a hydrogen atom or a monovalent organic residue having 1 to 11 carbon atoms. Group.)
A vinyl ether group-containing (meth) acrylic acid ester (hereinafter referred to as “monomer A”) represented by the following general formula (II):
CH ₂ = CH—O—R ⁴ (II)
(In the formula, R ⁴ is an alkyl group or a cycloalkyl group.)
The vinyl ether compound represented by these is mentioned. Among these, the monomer A is preferable for the following reasons.

  First, the monomer A is a compound having both a vinyl ether group and a (meth) acryloyl group in the molecule. When the ink composition contains the monomer A, the ink curability and the like can be further improved.

In the general formula (I), the divalent organic residue represented by R ² includes a linear, branched or cyclic alkylene group having 2 to 20 carbon atoms, an ether bond and an ester in the structure. An alkylene group having 2 to 20 carbon atoms having an oxygen atom due to at least one of the bonds, and an optionally substituted divalent aromatic group having 6 to 11 carbon atoms are preferable. Among these, C2-C6 alkylene groups such as ethylene group, n-propylene group, isopropylene group, and butylene group, oxyethylene group, oxy n-propylene group, oxyisopropylene group, and oxybutylene group An alkylene group having 2 to 9 carbon atoms having an oxygen atom due to an ether bond in the structure is preferably used.

In said general formula (I), as a C1-C11 monovalent organic residue represented by R < ³ >, a C1-C10 linear, branched or cyclic alkyl group, carbon An optionally substituted aromatic group of formula 6 to 11 is preferred. Among these, C6-C2 aromatic groups, such as a C1-C2 alkyl group which is a methyl group or an ethyl group, a phenyl group, and a benzyl group, are used suitably.

  When the above organic residue is an optionally substituted group, the substituent is divided into a group containing a carbon atom and a group not containing a carbon atom. First, when the substituent is a group containing a carbon atom, the carbon atom is counted in the carbon number of the organic residue. Examples of the group containing a carbon atom include, but are not limited to, a carboxyl group and an alkoxy group. Next, examples of the group not containing a carbon atom include, but are not limited to, a hydroxyl group and a halo group.

  Specific examples of the monomer A represented by the above general formula (I) include, but are not limited to, 2-vinyloxyethyl (meth) acrylate, 3-vinyloxypropyl (meth) acrylate, (meth) acrylic acid 1-methyl-2-vinyloxyethyl, 2-vinyloxypropyl (meth) acrylate, 4-vinyloxybutyl (meth) acrylate, 1-methyl-3-vinyloxypropyl (meth) acrylate, (meth) acrylic acid 1- Vinyloxymethylpropyl, 2-methyl-3-vinyloxypropyl (meth) acrylate, 1,1-dimethyl-2-vinyloxyethyl (meth) acrylate, 3-vinyloxybutyl (meth) acrylate, (meth) acrylic acid 1 -Methyl-2-vinyloxypropyl, 2-vinyloxybutyl (meth) acrylate, 4-bi (meth) acrylate Roxycyclohexyl, 6-vinyloxyhexyl (meth) acrylate, 4-vinyloxymethylcyclohexylmethyl (meth) acrylate, 3-vinyloxymethylcyclohexylmethyl (meth) acrylate, 2-vinyloxymethyl (meth) acrylate Cyclohexylmethyl, (meth) acrylic acid p-vinyloxymethylphenylmethyl, (meth) acrylic acid m-vinyloxymethylphenylmethyl, (meth) acrylic acid o-vinyloxymethylphenylmethyl, (meth) acrylic acid 2- ( Vinyloxyethoxy) ethyl, 2- (vinyloxyisopropoxy) ethyl (meth) acrylate, 2- (vinyloxyethoxy) propyl (meth) acrylate, 2- (vinyloxyethoxy) isopropyl (meth) acrylate, ( 2-methacrylic acid (vinyloxy) Propoxy) propyl, 2- (vinyloxyisopropoxy) isopropyl (meth) acrylate, 2- (vinyloxyethoxyethoxy) ethyl (meth) acrylate, 2- (vinyloxyethoxyisopropoxy) ethyl (meth) acrylate, 2- (vinyloxyisopropoxyethoxy) ethyl (meth) acrylate, 2- (vinyloxyisopropoxyisopropoxy) ethyl (meth) acrylate, 2- (vinyloxyethoxyethoxy) propyl (meth) acrylate, (meth ) 2- (vinyloxyethoxyisopropoxy) propyl acrylate, 2- (vinyloxyisopropoxyethoxy) propyl (meth) acrylate, 2- (vinyloxyisopropoxyisopropoxy) propyl (meth) acrylate, (meth) Acrylic acid 2- (vinyloxyethoxy ester) Toxi) isopropyl, (meth) acrylic acid 2- (vinyloxyethoxyisopropoxy) isopropyl, (meth) acrylic acid 2- (vinyloxyisopropoxyethoxy) isopropyl, (meth) acrylic acid 2- (vinyloxyisopropoxyisopropoxy) ) Isopropyl, 2- (vinyloxyethoxyethoxyethoxy) ethyl (meth) acrylate, 2- (vinyloxyethoxyethoxyethoxyethoxy) ethyl (meth) acrylate, 2- (isopropenoxyethoxy) ethyl (meth) acrylate , 2- (Isopropenoxyethoxyethoxy) ethyl (meth) acrylate, 2- (Isopropenoxyethoxyethoxyethoxy) ethyl (meth) acrylate, 2- (Isopropenoxyethoxyethoxyethoxyethoxy) acrylate (meth) acrylate ethyl (Meth) Polyethylene glycol monovinyl ether acrylate, and (meth) acrylic acid polypropylene glycol monovinyl ether.

  Among those described above, 2-vinyloxyethyl (meth) acrylate, 3-vinyloxypropyl (meth) acrylate, 1-methyl-2-vinyloxyethyl (meth) acrylate, 2-vinyloxypropyl (meth) acrylate, ( 4-vinyloxybutyl (meth) acrylate, 4-vinyloxycyclohexyl (meth) acrylate, 5-vinyloxypentyl (meth) acrylate, 6-vinyloxyhexyl (meth) acrylate, 4-vinyloxy (meth) acrylate Methylcyclohexylmethyl, p-vinyloxymethylphenylmethyl (meth) acrylate, 2- (vinyloxyethoxy) ethyl (meth) acrylate, 2- (vinyloxyethoxyethoxy) ethyl (meth) acrylate, (meth) acrylic The acid 2- (vinyloxyethoxyethoxyethoxy) ethyl is preferred Arbitrariness.

  Of these, 2- (vinyloxyethoxy) ethyl (meth) acrylate is preferred because of its low viscosity, high flash point, and excellent curability and storage stability. Since irritation can be suppressed and the reactivity is excellent, 2- (vinyloxyethoxy) ethyl acrylate is more preferable.

  Examples of 2- (vinyloxyethoxy) ethyl (meth) acrylate include 2- (2-vinyloxyethoxy) ethyl (meth) acrylate and 2- (1-vinyloxyethoxy) ethyl (meth) acrylate. Examples of 2- (vinyloxyethoxy) ethyl acrylate include 2- (2-vinyloxyethoxy) ethyl acrylate and 2- (1-vinyloxyethoxy) ethyl acrylate.

  The production method of the monomer A represented by the general formula (I) is not limited to the following, but is a method of esterifying (meth) acrylic acid and a hydroxyl group-containing vinyl ether (production method B), (meth) acrylic acid. Method of esterifying halide and hydroxyl group-containing vinyl ether (Production method C), Method of esterifying (meth) acrylic anhydride and hydroxyl group-containing vinyl ether (Production method D), (Meth) acrylic acid ester and hydroxyl group Method of Transesterifying Containing Vinyl Ethers (Production Method E), Method of Esterifying (Meth) acrylic Acid and Halogen-Containing Vinyl Ethers (Production Method F), Alkali (Meth) Acrylic Acid (Earth) Metal Salt and Halogen Containing Method of esterifying vinyl ethers (Production G), hydroxyl group-containing (meth) acrylic acid esters and carboxylic acid vinyl ester How to vinyl exchange and Le (Procedure H), hydroxyl group-containing (meth) How to ether exchange and acrylic acid esters and alkyl vinyl ethers (formula I).

  Among these, since the desired effect can be further exhibited in this embodiment, the production method E is preferable.

Next, in the above general formula (II), examples of the alkyl group represented by R ⁴ include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, tert-butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, dodecyl group, tetradecyl group, pentadecyl group, hexadecyl group, octadecyl group, eicosyl group, etc. A chain or branched alkyl group is preferred. Examples of the cycloalkyl group represented by R ⁴ include those having 3 to 20 carbon atoms such as cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, cyclooctyl group, methylcyclohexyl group, and decahydronaphthyl group. Preferably mentioned.

  Specific examples of the vinyl ether compound represented by the general formula (II) include, but are not limited to, methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, pentyl vinyl ether, hexyl vinyl ether, 2-ethylhexyl vinyl ether, and decyl vinyl ether. Preferred examples include alkyl vinyl ethers such as cyclopentyl vinyl ether and cyclohexyl vinyl ether.

  The polymerizable compound having a vinyl ether group may be used alone or in combination of two or more.

(Polymerizable compound having (meth) acryloyl group)
The polymerizable compound having a (meth) acryloyl group is a compound containing at least one of acryloyl group and methacryloyl group (preferably acryloyl group). That is, in this specification, “polymerizable compound having (meth) acryloyl group” is only a polymerizable compound having only (meth) acryloyl group among N-vinyl group, vinyl ether group and (meth) acryloyl group. A polymerizable compound having only (meth) acryloyl group and N-vinyl group, a polymerizable compound having only (meth) acryloyl group and vinyl ether group, and (meth) acryloyl group, vinyl ether group and N-vinyl group And a polymerizable compound having:

  As a polymerizable compound having the (meth) acryloyl group, a monomer such as a monofunctional, bifunctional, or polyfunctional (trifunctional or higher) (meth) acrylic acid salt or ester, and an oligomer formed from the monomer, Examples include oligomers such as epoxy (meth) acrylate, oxetane (meth) acrylate, aliphatic urethane (meth) acrylate, aromatic urethane (meth) acrylate, and polyester (meth) acrylate.

  Among these, an ester of (meth) acrylic acid, that is, (meth) acrylate is preferable, polyfunctional (meth) acrylate having two or more functions is more preferable, and polyfunctional acrylate is more preferable. In particular, when the ink composition of the present embodiment contains a polyfunctional acrylate as the polymerizable compound, the curability, adhesion, and storage stability become better.

  Among the above (meth) acrylates, monofunctional (meth) acrylates include, for example, isoamyl (meth) acrylate, stearyl (meth) acrylate, lauryl (meth) acrylate, octyl (meth) acrylate, decyl (meth) acrylate, iso Myristyl (meth) acrylate, isostearyl (meth) acrylate, 2-ethylhexyl-diglycol (meth) acrylate, 2-hydroxybutyl (meth) acrylate, butoxyethyl (meth) acrylate, ethoxydiethylene glycol (meth) acrylate, methoxydiethylene glycol ( (Meth) acrylate, methoxypolyethylene glycol (meth) acrylate, methoxypropylene glycol (meth) acrylate, phenoxyethyl (meth) acrylate , Tetrahydrofurfuryl (meth) acrylate, isobornyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, lactone-modifiable Examples include flexible (meth) acrylate, t-butylcyclohexyl (meth) acrylate, dicyclopentanyl (meth) acrylate, and dicyclopentenyloxyethyl (meth) acrylate.

  Among the above (meth) acrylates, as the polyfunctional (meth) acrylate, for example, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, dipropylene glycol di ( (Meth) acrylate, tripropylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, 1,9-nonane Diol (meth) acrylate, neopentyl glycol di (meth) acrylate, dimethylol-tricyclodecane di (meth) acrylate, di (meth) acrylate of bisphenol A, neope hydroxypivalate Bifunctional (meth) acrylates such as tilglycol di (meth) acrylate and polytetramethylene glycol di (meth) acrylate, and trimethylolpropane tri (meth) acrylate, glycerin propoxytri (meth) acrylate, cowprolactone modified Trimethylolpropane tri (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, sorbitol penta (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, and pentaerythritol ethoxytetra (meth) acrylate (Meth) acrylate having a pentaerythritol skeleton such as dipentaerythritol hexa (meth) acrylate, caprolactam modification (Meth) acrylate having a dipentaerythritol skeleton such as pentaerythritol hexa (meth) acrylate, dipentaerythritol penta (meth) acrylate, and caprolactone-modified dipentaerythritol hexa (meth) acrylate, propionate-modified tripentaerythritol penta (meta) ) Acrylate, tripentaerythritol hexa (meth) acrylate, tripentaerythritol hepta (meth) acrylate, tripentaerythritol octa (meth) acrylate and other (meth) acrylates having a tetrapentaerythritol skeleton, tetrapentaerythritol penta (meth) Acrylate, tetrapentaerythritol hexa (meth) acrylate, tetrapentaerythritol hepta (meth) a (Meth) acrylates having a tetrapentaerythritol skeleton such as acrylate, tetrapentaerythritol octa (meth) acrylate, tetrapentaerythritol nona (meth) acrylate, tetrapentaerythritol nona (meth) acrylate, and tetrapentaerythritol deca (meth) acrylate , (Pentaerythritol undeca (meth) acrylate) and pentapentaerythritol dodeca (meth) acrylate and other (meth) acrylates having a pentapentaerythritol skeleton, and ethylene oxide (EO) adducts and propylene oxide (PO) adducts thereof Among them, trifunctional or higher functional (meth) acrylates are included.

  Among these, the polymerizable compound having a (meth) acryloyl group preferably includes a polyfunctional (meth) acrylate as described above. Among the polyfunctional (meth) acrylates, the polyfunctional (meth) acrylate having the pentaerythritol skeleton is preferable, and at least one of pentaerythritol tri (meth) acrylate and pentaerythritol tetra (meth) acrylate is more preferable. At least one of erythritol triacrylate and pentaerythritol tetraacrylate is more preferable.

  Among monofunctional (meth) acrylates, in order to reduce viscosity and odor, at least one of phenoxyethyl (meth) acrylate and isobornyl (meth) acrylate is preferred, phenoxyethyl (meth) acrylate is more preferred, and phenoxy More preferred is ethyl acrylate.

  The polymerizable compound having the (meth) acryloyl group may be used alone or in combination of two or more.

(Polymerizable compounds other than the above)
The polymerizable compound in the present embodiment may include a polymerizable compound other than the above (hereinafter referred to as “other polymerizable compound”). As used herein, “other polymerizable compounds” refers to compounds that do not contain any N-vinyl group, vinyl ether group, or acryloyl group as a polymerizable group.

  As the other polymerizable compound, conventionally known various monomers and oligomers such as monofunctional, bifunctional, and trifunctional or more polyfunctional can be used. Examples of the monomer include unsaturated carboxylic acids such as itaconic acid, crotonic acid, isocrotonic acid and maleic acid, salts or esters thereof, urethanes, amides and anhydrides thereof, acrylonitrile, styrene, various unsaturated polyesters, unsaturated monomers. Examples include saturated polyethers, unsaturated polyamides, and unsaturated urethanes. Moreover, as said oligomer, the oligomer formed from said monomer is mentioned, for example.

  The said other polymeric compound may be used individually by 1 type, and may be used in combination of 2 or more type.

(Polymerization inhibitor)
The ink composition of this embodiment may contain a polymerization inhibitor. Examples of polymerization inhibitors include, but are not limited to, p-methoxyphenol, cresol, t-butylcatechol, di-t-butylparacresol, hydroquinone monomethyl ether, α-naphthol, 3,5-di-t-butyl. -4-hydroxytoluene, 2,2'-methylenebis (4-methyl-6-t-butylphenol), 2,2'-methylenebis (4-ethyl-6-butylphenol), and 4,4'-thiobis (3- Phenol compounds such as methyl-6-tert-butylphenol), p-benzoquinone, anthraquinone, naphthoquinone, phenanthraquinone, p-xyloquinone, p-toluquinone, 2,6-dichloroquinone, 2,5-diphenyl-p-benzoquinone 2,5-diacetoxy-p-benzoquinone, 2,5-dicaproxy-p- Quinone compounds such as nzoquinone, 2,5-diacyloxy-p-benzoquinone, hydroquinone, 2,5-dibutylhydroquinone, mono-t-butylhydroquinone, monomethylhydroquinone, and 2,5-di-t-amylhydroquinone, phenyl- β-naphthylamine, p-benzylaminophenol, di-β-naphthylparaphenylenediamine, amine compounds such as dibenzylhydroxylamine, phenylhydroxylamine, and diethylhydroxylamine, nitro compounds such as dinitrobenzene, trinitrotoluene, and picric acid , Oxime compounds such as quinonedioxime and cyclohexanone oxime, and sulfur compounds such as phenothiazine.

(Photopolymerization initiator)
The ink composition of this embodiment contains a photopolymerization initiator. The photopolymerization initiator is used to form an image by curing ink present on the surface of a recording medium by photopolymerization by irradiation with ultraviolet rays.

  The inventors of the present invention have found that a desired effect can be achieved in the present embodiment by diligently examining and defining the ratio in consideration of the difference in reactivity of the three polymerizable groups in the ink system. Specifically, the number ratio of N-vinyl groups is preferably in the range of 1.5 to 3.05 with respect to one photocleavable part in the photopolymerization initiator. When the number ratio of N-vinyl groups is 1.5 or more, polymerization (curing) proceeds sufficiently. Further, when the number ratio of N-vinyl groups is 3.0 or less, the curing reaction during ink storage is prevented, and the storage stability is improved.

  Here, the photopolymerization initiator is not limited as long as it generates active species such as radicals and cations by the energy of light and initiates polymerization of the polymerizable compound. An agent or a photocationic polymerization initiator can be used, and among them, it is preferable to use a more general photoradical polymerization initiator.

  Examples of the photo radical polymerization initiator include aromatic ketones, acyl phosphine oxide compounds, aromatic onium salt compounds, organic peroxides, thio compounds (thioxanthone compounds, thiophenyl group-containing compounds, etc.), hexaarylbiphenyls, and the like. Examples include imidazole compounds, ketoxime ester compounds, borate compounds, azinium compounds, metallocene compounds, active ester compounds, compounds having a carbon halogen bond, and alkylamine compounds.

  Among these, an acyl phosphine oxide compound is preferable because the curability of the ink can be further improved.

  Specific examples of the photo radical polymerization initiator include acetophenone, acetophenone benzyl ketal, 1-hydroxycyclohexyl phenyl ketone, 2,2-dimethoxy-2-phenylacetophenone, xanthone, fluorenone, benzaldehyde, fluorene, anthraquinone, triphenylamine. , Carbazole, 3-methylacetophenone, 4-chlorobenzophenone, 4,4′-dimethoxybenzophenone, 4,4′-diaminobenzophenone, Michler's ketone, benzoin propyl ether, benzoin ethyl ether, benzyldimethyl ketal, 1- (4-isopropylphenyl) ) -2-hydroxy-2-methylpropan-1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one, thioxanthone, diethylthio Xanthone, 2-isopropylthioxanthone, 2-chlorothioxanthone, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino-propan-1-one, bis (2,4,6-trimethylbenzoyl) -phenyl Phosphine oxide, 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, 2,4-diethylthioxanthone, and bis- (2,6-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide Can be mentioned.

  Examples of commercially available photo radical polymerization initiators include IRGACURE 651 (2,2-dimethoxy-1,2-diphenylethane-1-one), IRGACURE 184 (1-hydroxy-cyclohexyl-phenyl-ketone), DAROCUR 1173. (2-hydroxy-2-methyl-1-phenyl-propan-1-one), IRGACURE 2959 (1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propane- 1-one), IRGACURE 127 (2-hydroxy-1- {4- [4- (2-hydroxy-2-methyl-propionyl) -benzyl] phenyl] -2-methyl-propan-1-one}, IRGACURE 907 (2-Methyl-1- (4-methylthiophenyl) -2-morphol Linopropan-1-one), IRGACURE 369 (2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1), IRGACURE 379 (2- (dimethylamino) -2-[(4- Methylphenyl) methyl] -1- [4- (4-morpholinyl) phenyl] -1-butanone), DAROCUR TPO (2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide), IRGACURE 819 (bis (2, 4,6-trimethylbenzoyl) -phenylphosphine oxide), IRGACURE 784 (bis (η5-2,4-cyclopentadien-1-yl) -bis (2,6-difluoro-3- (1H-pyrrole-1-) Yl) -phenyl) titanium), IRGACURE OXE 01 (1.2-octanedione, 1- [4- (phenylthio)-, 2- (O-benzoyloxime)]), IRGACURE OXE 02 (ethanone, 1- [9-ethyl-6- (2-methylbenzoyl) -9H-carbazol-3-yl]-, 1- (O-acetyloxime)), IRGACURE 754 (oxyphenylacetic acid, 2- [2-oxo-2-phenylacetoxyethoxy] ethyl ester and oxyphenylacetic acid, 2- (Mixture of (2-hydroxyethoxy) ethyl ester) (above, manufactured by BASF), Speedcure TPO (manufactured by Lambson), KAYACURE DETX-S (2,4-diethylthioxanthone) (Nippon Kayaku Co., Ltd.) Ltd.), Lucirin TPO, LR8883, LR8970 (above, manufactured by BASF), Such as fine Ubecryl P36 (manufactured by UCB), and the like.

  The said photoinitiator may be used individually by 1 type, and may be used in combination of 2 or more type.

  The photopolymerization initiator sufficiently exhibits the ultraviolet curing rate, and avoids undissolved photopolymerization initiator and coloring derived from the photopolymerization initiator, so that the total mass (100% by mass) of the ink composition is used. 5 to 20% by mass is preferable.

[Color material]
The ink composition of the present embodiment preferably further includes a color material. As the color material, at least one of a pigment and a dye can be used.

(Pigment)
In this embodiment, the light resistance of the ink composition can be improved by using a pigment as the coloring material. As the pigment, both inorganic pigments and organic pigments can be used.

  As the inorganic pigment, carbon black (CI pigment black 7) such as furnace black, lamp black, acetylene black and channel black, iron oxide, and titanium oxide can be used. Among these, as a commercial product of titanium oxide, Tipaque (registered trademark) CR-60-2 (trade name, manufactured by ISHIHARA SANGYO KAISHA, LTD.) Can be mentioned.

  Organic pigments include insoluble azo pigments, condensed azo pigments, azo lakes, chelate azo pigments, etc., phthalocyanine pigments, perylene and perinone pigments, anthraquinone pigments, quinacridone pigments, dioxane pigments, thioindigo pigments, isoindolinone pigments, quinophthalone pigments, etc. Polycyclic pigments, dye chelates (eg basic dye chelates, acid dye chelates, etc.), dye rakes (basic dye rakes, acid dye rakes), nitro pigments, nitroso pigments, aniline black, daylight A fluorescent pigment is mentioned.

  More specifically, as carbon black used as black ink, No. 2300, no. 900, MCF88, No. 33, no. 40, no. 45, no. 52, MA7, MA8, MA100, no. 2200B and the like (manufactured by Mitsubishi Chemical Corporation), Raven 5750, Raven 5250, Raven 5000, Raven 3500, Raven 1255, Raven 700, etc. (and above, manufactured by Columbia Columbia), Regal 400R, Rega1 330R, Rega1 660R, Mogul L, Monarch 700, Monarch 800, Monarch 880, Monarch 900, Monarch 1000, Monarch 1100, Monarch 1300, Monarch 1400, etc. (from CABOT JAPAN K. F. C. , Color Black FW2, Color Black FW2V, Color Black FW 18, Color Black FW200, Color B1ack S150, Color Black S160, Color Black S170, Printex 35, Printex U, Printex V, Printex 140U, Special Black 6, Sep, Special Black S6, Color Black S160, Color Black S160, Color Black S170, Color Black S170, Color Black S170, Color Black S170, Color Black S170, Color Black S170, Color Black S170 Degussa)).

  Examples of pigments used in white ink include C.I. I. Pigment white 6, 18, and 21.

  Examples of pigments used in yellow ink include C.I. I. Pigment Yellow 1, 2, 3, 4, 5, 6, 7, 10, 11, 12, 13, 14, 16, 17, 24, 34, 35, 37, 53, 55, 65, 73, 74, 75, 81, 83, 93, 94, 95, 97, 98, 99, 108, 109, 110, 113, 114, 117, 120, 124, 128, 129, 133, 138, 139, 147, 151, 153, 154, 167, 172, 180.

  Examples of pigments used in magenta ink include C.I. I. Pigment Red 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 14, 15, 16, 17, 18, 19, 21, 22, 23, 30, 31, 32, 37, 38, 40, 41, 42, 48 (Ca), 48 (Mn), 57 (Ca), 57: 1, 88, 112, 114, 122, 123, 144, 146, 149, 150, 166, 168 170, 171, 175, 176, 177, 178, 179, 184, 185, 187, 202, 209, 219, 224, 245, or C.I. I. Pigment violet 19, 23, 32, 33, 36, 38, 43, 50.

  Examples of pigments used for cyan ink include C.I. I. Pigment Blue 1, 2, 3, 15, 15: 1, 15: 2, 15: 3, 15:34, 15: 4, 16, 18, 22, 25, 60, 65, 66, C.I. I. Bat Blue 4, 60.

  Examples of pigments other than magenta, cyan, and yellow include C.I. I. Pigment green 7,10, C.I. I. Pigment brown 3, 5, 25, 26, C.I. I. Pigment orange 1, 2, 5, 7, 13, 14, 15, 16, 24, 34, 36, 38, 40, 43, 63.

  The said pigment may be used individually by 1 type, and may be used in combination of 2 or more type.

  When the above pigment is used, the average particle size is preferably 300 nm or less, and more preferably 50 to 250 nm. When the average particle diameter is in the above range, the ink composition is more excellent in reliability such as ejection stability and dispersion stability, and an image with excellent image quality can be formed. Here, the average particle diameter in the present specification is measured by a dynamic light scattering method.

(dye)
In the present embodiment, a dye can be used as the color material. The dye is not particularly limited, and acid dyes, direct dyes, reactive dyes, and basic dyes can be used. Examples of the dye include C.I. I. Acid Yellow 17, 23, 42, 44, 79, 142, C.I. I. Acid Red 52, 80, 82, 249, 254, 289, C.I. I. Acid Blue 9, 45, 249, C.I. I. Acid Black 1, 2, 24, 94, C.I. I. Food Black 1, 2, C.I. I. Direct Yellow 1,12,24,33,50,55,58,86,132,142,144,173, C.I. I. Direct Red 1,4,9,80,81,225,227, C.I. I. Direct Blue 1, 2, 15, 71, 86, 87, 98, 165, 199, 202, C.I. I. Directed Black 19, 38, 51, 71, 154, 168, 171, 195, C.I. I. Reactive Red 14, 32, 55, 79, 249, C.I. I. Reactive black 3, 4, and 35 are mentioned.

  The said dye may be used individually by 1 type, and may be used in combination of 2 or more type.

  The content of the color material is preferably 1 to 20% by mass with respect to the total mass (100% by mass) of the ink composition because excellent concealability and color reproducibility are obtained.

[Dispersant]
When the ink composition of this embodiment contains a pigment, it may further contain a dispersant in order to improve pigment dispersibility. Although it does not specifically limit as a dispersing agent, For example, the dispersing agent currently used for preparing pigment dispersion liquids, such as a polymer dispersing agent, is mentioned. Specific examples include polyoxyalkylene polyalkylene polyamines, vinyl polymers and copolymers, acrylic polymers and copolymers, polyesters, polyamides, polyimides, polyurethanes, amino polymers, silicon-containing polymers, sulfur-containing polymers, fluorine-containing polymers, and epoxies. The thing which has 1 or more types of resin as a main component is mentioned. Commercially available polymer dispersants include Ajinomoto Fine Techno Co., Ajisper series, Solsperz series available from Avecia Co. (Solsperse 36000, etc.), BYK Dispervic series, Enomoto Kasei Co., Ltd. Disparon series made by the company.

[Slip agent]
The ink composition of the present embodiment may further contain a slip agent (surfactant) because excellent abrasion resistance is obtained. The slip agent is not particularly limited. For example, polyester-modified silicone or polyether-modified silicon can be used as the silicon-based surfactant, and polyether-modified polydimethylsiloxane or polyester-modified polydimethylsiloxane is particularly used. preferable. Specific examples include BYK-347, BYK-348, BYK-UV3500, 3510, 3530, and 3570 (above, manufactured by BYK).

[Other additives]
The ink composition of the present embodiment may include additives (components) other than the additives listed above. Such components are not particularly limited, and may include, for example, conventionally known polymerization accelerators, penetration enhancers, wetting agents (humectants), and other additives. Examples of the other additives include conventionally known fixing agents, antifungal agents, preservatives, antioxidants, ultraviolet absorbers, chelating agents, pH adjusting agents, and thickeners.

[Recording medium]
The ultraviolet curable inkjet ink composition of the present embodiment can be recorded by being ejected onto a recording medium using an inkjet recording method described later. As the recording medium, a package substrate or a semiconductor substrate is preferable. This is because the ink used for marking on a package substrate or the like is required to have excellent curability, adhesion, and storage stability.

  As defined above, the package base material means a protective base material that encloses semiconductor chips and the like, and the semiconductor base material also includes a wafer that is a semiconductor chip or the like and also directly serves as a base material. . Then, an electronic component (IC package) is manufactured by enclosing the semiconductor chip or the like. An electronic device is formed by integrating one or more of these electronic components.

  As the standard of the package substrate, for example, PGA (Pin Grid Array), DIP (Dual Inline Package), SIP (Single Inline Package), ZIP (Zigzag Inline Package), DO (Diode Outline) package, and TO (Transistoristor). ) Insertion type packages such as packages, as well as P-BGA (Plastic Ball grid array), T-BGA (Tape Ball grid array), F-BGA (Fine Pitch Ball grid array), SOJ (Small Outline J-OP) (Thin Small Outline Package), SON Small Outline Non-lead), QFP (Quad Flat Package), CFP (Ceramic Flat Package), SOT (Small Outline Transistor), PLCC (Plastic led chip carrier, L), GA (L) And surface mount packages such as TCP (Tape carrier package), LLP (Leadless Leadframe Package), and DFN (Dual Flatpack Non-lead).

  As a commercially available package base material, for example, a general purpose logic IC package (SOP14-P-300-1.27A) manufactured by Toshiba Semi-Conductor Co., Ltd., Renesas Electronics Corporation Surface mount package (UPA2350B1G) manufactured by Sharp Corporation, surface mount package package (P-LFBGA048-0606) manufactured by Sharp Corporation, and serial EEPROM (BR24L01A) manufactured by ROHM Co., Ltd. It is done.

  As a material of the package base material, a non-absorbable material can be used in order to prevent ink from penetrating into the electronic component main body. Specific examples of the non-absorbing material include, but are not limited to, metals such as gold, silver, copper, aluminum, iron-nickel alloys, stainless steel, and brass, and semiconductors (for example, silicon), carbides, nitrides. And inorganic substances such as borides (eg silicon nitride) and organic substances such as silicon, epoxy resins, phenolic resins, polyimides, and polymethyl methacrylate (PMMA).

  Especially, since it is excellent in adhesiveness with ink, as a package base material, a silicone or an epoxy resin is more preferable. Thus, by using a package substrate made of silicon or epoxy resin as a sealing material for electronic components, the ink composition of the above embodiment can be suitably recorded (marked) on the outer surface of the package substrate. it can.

  On the other hand, commercially available semiconductor substrates (wafers) include, for example, a 300 mm silicon wafer manufactured by Shin-Etsu Chemical Co., Ltd., an SOI wafer manufactured by SUMCO, and Covalent Materials. Corporation).

  Examples of the material for the semiconductor substrate include silicon, germanium, and selenium. Among these, silicon is preferable because it is most frequently used, has excellent adhesion to ink, and is extremely stable as a semiconductor material.

  Examples of the electronic device include a flash memory card such as a USB memory, a memory card, an SD memory card, a memory stick, a smart media, an xD picture card, and a compact flash (registered trademark).

  Here, a marking method for a package substrate or the like will be described.

  First, when marking on a wafer as a semiconductor substrate, it may be marked on a wafer before dicing, or after forming a circuit on the wafer and marking on a semiconductor chip diced into chips. May be. In the latter case, a silicon wafer on which an IC (integrated circuit) is formed generally forms a silicon oxide film on the wafer surface during the circuit formation process. As a method for forming the silicon oxide film, for example, a high frequency sputtering method which is one of the methods excellent in controlling the thickness can be given. Using this method, silicon dioxide as a target material can be sputtered onto a silicon wafer.

  Next, when marking on the package substrate, the semiconductor chip may be marked on the package substrate after encapsulation, or on the package substrate before encapsulation of the semiconductor chip.

The electronic component is manufactured by bonding a pad of a semiconductor chip and a lead frame and encapsulating the entire chip together with a sealing agent in a package substrate. Examples of the sealant include, but are not limited to, an epoxy resin, a phenol resin, and a silicon resin. Marking can be performed on the electronic component thus manufactured (outer surface).
In addition, when the ink composition is applied to a non-absorbable recording medium, it may be necessary to provide a drying step after being cured by irradiation with ultraviolet rays.

  As described above, according to the present embodiment, it is possible to provide an ultraviolet curable inkjet ink composition that is excellent in curability, adhesion, and storage stability.

[Recordings]
One embodiment of the present invention relates to a recorded matter. In the recorded matter, the ink composition of the embodiment is recorded on a package base material as a recording medium, and the ink composition recorded on the package base material and the package base material. And a cured product. The recorded matter is characterized by excellent curability and storage stability of the ink composition, and excellent adhesion between the package substrate and the ink composition (cured product) adhered and cured thereon.

[Inkjet recording method]
One embodiment of the present invention relates to an inkjet recording method. The ink jet recording method includes a discharge step of discharging the ink composition of the above embodiment onto a package substrate or the like (recording medium), and a peak emission wavelength within a predetermined range in the ink composition discharged by the discharge step. And a curing step of curing the ink composition by irradiating with ultraviolet rays. In this way, a cured film (coating film) is formed by the ink composition cured on the package substrate or the like. Hereafter, each said process is demonstrated in detail.

[Discharge process]
In the ejection step, a conventionally known ink jet recording apparatus can be used. When discharging the ink composition, the viscosity of the ink composition is preferably 30 mPa · s or less, and more preferably 5 to 20 mPa · s. If the viscosity of the ink composition is as described above with the temperature of the ink composition at room temperature or without heating the ink composition, the temperature of the ink composition is at room temperature or without heating the ink composition. Can be discharged. On the other hand, the ink composition may be discharged to a preferable viscosity by heating to a predetermined temperature. In this way, good discharge stability is realized.

[Curing process]
Next, in the curing step, the ink composition discharged onto the package substrate or the like is cured by irradiation with ultraviolet rays.

  Specifically, the polymerization reaction of the polymerizable compound starts upon irradiation with ultraviolet rays. In addition, the photopolymerization initiator contained in the ink composition is decomposed by irradiation with ultraviolet rays to generate starting species such as radicals, acids, and bases, and the polymerization reaction of the polymerizable compound is accelerated by the function of the starting species. Is done. At this time, if a sensitizing dye is present together with the photopolymerization initiator in the ink composition, the sensitizing dye in the system absorbs ultraviolet rays to be in an excited state and contacts the photopolymerization initiator to decompose the photopolymerization initiator. And a more sensitive curing reaction can be achieved.

  Mercury lamps and gas / solid lasers are mainly used as ultraviolet sources, and mercury lamps and metal halide lamps are widely known as light sources used for curing ultraviolet curable ink-jet ink compositions. . On the other hand, there is a strong demand for mercury-free from the viewpoint of environmental protection, and replacement with a GaN-based semiconductor ultraviolet light-emitting device is very useful industrially and environmentally. Furthermore, ultraviolet light-emitting diodes (UV-LEDs) and ultraviolet laser diodes (UV-LDs) are small, have a long lifetime, high efficiency, and are low in cost, and are expected as light sources for ultraviolet curable ink jets. Among these, UV-LED is preferable.

Here, an ink composition that can be cured by irradiation with ultraviolet rays having an emission peak wavelength of preferably 350 to 400 nm, more preferably 365 to 395 nm is used. The irradiation energy is preferably from 800 mJ / cm ² or less, 200~700mJ / cm ² is more preferable.

  In the above case, curing at low energy and high speed is possible due to the composition of the ink composition of the above embodiment. The irradiation energy is calculated by multiplying the irradiation time by the irradiation intensity. The irradiation time can be shortened by the composition of the ink composition of the above embodiment, and in this case, the printing speed is increased. On the other hand, the irradiation intensity can be reduced by the composition of the ink composition of the above embodiment, and in this case, the apparatus can be downsized and the cost can be reduced. In this case, UV-LED is preferably used for ultraviolet irradiation. Such an ink composition can be obtained by including a photopolymerization initiator that is decomposed by irradiation with ultraviolet rays in the above wavelength range and a polymerizable compound that initiates polymerization by irradiation with ultraviolet rays in the above wavelength range. The emission peak wavelength may be one or plural within the above wavelength range. Even in the case where there are a plurality, the total irradiation energy of the ultraviolet rays having the emission peak wavelength is set as the irradiation energy.

  As described above, according to this embodiment, it is possible to suitably record an ultraviolet curable inkjet ink composition excellent in curability, adhesion, and storage stability on a package substrate or a semiconductor substrate. An ink jet recording method can be provided.

  Hereinafter, the embodiments of the present invention will be described more specifically by way of examples. However, the embodiments are not limited to these examples.

[Raw materials]
The raw materials used in the following examples and comparative examples are as follows.
(Polymerizable compound)
VEEA (2- (2-vinyloxyethoxy) ethyl acrylate, trade name of Nippon Shokubai Co., Ltd., abbreviated as VEEA in Tables 1 to 4)
V-CAP (N-vinylcaprolactam, trade name of ISP, abbreviated as NVC in Tables 1 and 3)
Biscoat # 192 (phenoxyethyl acrylate, trade name of Osaka Organic Chemical Industry Co., Ltd., abbreviated as PEA in Tables 1 and 3)
SR-444 (pentaerythritol triacrylate, trade name of Sartomer Co., abbreviated as PETA in Tables 1 and 3)
V-Pyrol (N-vinylpyrrolidone, trade name of ISP, abbreviated as VP in Tables 2 and 4)
V # 150 (tetrahydrofurfuryl acrylate, trade name of Osaka Organic Chemical Industry Co., Ltd., abbreviated as THFA in Tables 2 and 4)
APG-100 (dipropylene glycol diacrylate, trade name of Shin-Nakamura Chemical Co., Ltd., abbreviated as DPGDA in Tables 2 and 4)
(Photopolymerization initiator)
IRGACURE 819 (trade name, manufactured by BASF, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, solid content: 100%, abbreviated as 819 in Tables 1 to 4)
DAROCURE TPO (trade name, manufactured by BASF, 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, solid content 100%, abbreviated as TPO in Tables 1 to 4)
[Slip agent]
Silicon-based surface conditioner BYK-UV3500 (polydimethylsiloxane having a polyether-modified acrylic group, trade name of BYK, abbreviated as UV3500 in Tables 1 to 4)
(Polymerization inhibitor)
P-methoxyphenol (KANTO CHEMICAL CO., INC, abbreviated as MEHQ in Tables 1 to 4)
[Pigment]
Tipaque (registered trademark) CR-60-2 (trade name, titanium oxide, manufactured by ISHIHARA SANGYO KAISHA, LTD., Abbreviated as TiO ₂ in Tables 1 to 4)
[Dispersant]
・ Solsperse 36000 (trade name manufactured by LUBRIZOL)

〔Base material〕
Base material 1 (package base material): Epoxy resin surface 1 (manufactured by Sharp Corporation, surface mount package, model number “P-LFBGA048-0606”)
-Base material 2 (semiconductor base material): Silicon surface 2 (manufactured by SUMCO, SOI wafer)
Base material 3 (other base materials): PET50A (PET film manufactured by Lintec Corporation)

  In addition, the said base material 2 used what formed the circuit and diced into the semiconductor chip. During circuit formation, the thickness of the silicon oxide layer on the wafer surface was 50 nm.

[Examples 1-14, Comparative Examples 1-16]
(Preparation of pigment dispersion)
Prior to preparation of the ink composition, a pigment dispersion was prepared. 60% by mass of the pigment, 5% by mass of the dispersant, and 35% by mass of VEEA as the polymerizable compound were mixed and stirred with a stirrer for 1 hour. The mixed liquid after stirring was dispersed with a bead mill to obtain a pigment dispersion. The dispersion conditions were such that zirconia beads having a diameter of 0.65 mm were filled at a filling rate of 70%, the peripheral speed was 9 m / s, and the dispersion time was 2 to 4 hours.

[Preparation of ink composition]
The components described in Tables 1 to 4 below were added so as to have the compositions (units: mass%) described in Tables 1 to 4 (in Tables 1 to 4, the pigment and a part of VEEA are the above pigment dispersions) This was mixed and stirred at room temperature for 1 hour to be completely dissolved. This was further filtered through a 5 μm membrane filter to obtain each ultraviolet curable ink composition for inkjet.

  In Tables 1 to 4, the dispersant in the pigment dispersion is not described because its composition can be calculated based on the content of the pigment and VEEA which are solid contents. Further, “vinyl ether group / N-vinyl group”, “acryloyl group / vinyl ether group”, and “N-vinyl group / photocleavable part” are the contents of the group or photocleavable part shown in the denominator in the ink composition, respectively. The content of the group shown in the molecule with respect to is shown by the number ratio.

[Evaluation item]
About the ultraviolet curable inkjet ink composition prepared in each Example and comparative example, sclerosis | hardenability, adhesiveness, and storage stability were evaluated with the following method.

[Curing property]
Using the inkjet printer PX-G5000 (trade name, manufactured by Seiko Epson Corporation), each of the nozzle rows was filled with the ultraviolet curable inkjet ink composition. A solid pattern image was printed on the substrate 1 at normal temperature and normal pressure under the conditions of a recording resolution of 720 dpi × 720 dpi and a droplet weight of 7 ng. Note that this solid pattern image is an image in which dots are recorded for all of the pixels that are the minimum recording unit area defined by the recording resolution.
Along with the printing described above, a solid pattern image is obtained by irradiating UV light having an irradiation intensity of 400 mW / cm ² and a wavelength of 395 nm with 600 mJ / cm ² from the UV-LED in the UV irradiation device mounted on the side of the carriage. Cured. In addition, it was judged that it was hardened | cured when the tackiness of the image (coating film surface) disappeared by the finger touch test.

Evaluation was performed by calculating the irradiation energy of ultraviolet rays required for curing. The irradiation energy [mJ / cm ² ] was determined from the product of the irradiation intensity [mW / cm ² ] on the irradiated surface irradiated from the light source and the irradiation duration [s]. The irradiation intensity was measured using an ultraviolet intensity meter UM-10 and a light receiving unit UM-400 (both manufactured by KONICA MINOLTA SENSING, INC.).
The evaluation criteria are as follows. ◎ and ○ are practically acceptable evaluation criteria. The evaluation results are shown in Table 5 below.
A: Less than 300 mJ / cm ²
○: 300 mJ / cm ² or more and less than 500 mJ / cm ²
X: 500 mJ / cm ² or more.

[Adhesion]
The same solid pattern image as the curable evaluation item was printed on the substrates 1 to 3, and then the same ultraviolet rays as the curable evaluation item were applied until the solid pattern image was cured.

And according to JIS K-5600-5-6 (ISO2409) (Coating General Test Method-Part 5: Mechanical Properties of Coating Film-Section 6: Adhesiveness (Crosscutting Method)) 1 to 3 and an image formed by solid printing were evaluated for adhesion. Here, the cross-cut method will be described.
As a cutting tool, a single blade cutting tool (a cutter that is generally commercially available) and a guide for cutting at equal intervals using a single blade cutting tool were prepared.

  First, the cutting tool blade was applied so as to be perpendicular to the coating film, and six cuts were made in the recorded matter. After making these six cuts, the direction of 90 ° was changed, and another six cuts were made so as to be perpendicular to the cuts already made.

  Next, take out the transparent adhesive tape (width 25 ± 1 mm) so that the length is about 75 mm, attach the tape to the grid-cut portion formed on the coating film, and finger enough to see through the coating film. I rubbed the tape. Next, within 5 minutes of adhesion, it was reliably pulled apart at an angle close to 60 ° in 0.5 to 1.0 seconds.

The evaluation criteria are as follows. ◎ and ○ are practically acceptable evaluation criteria. The evaluation results are shown in Table 5 below.
A: Peeling is hardly seen in any lattice eye (rank 0 or rank 1 in JIS K-5600-5-6).
○: Peeling is recognized in part of the lattice (rank 2 or rank 3 in JIS K-5600-5-6).
X: Peeling is observed in 50% or more of the lattice (rank 4 or rank 5 in JIS K-5600-5-6).

[Storage stability]
24 mL of each of the ink compositions described above was put into a 30 mL glass bottle and left standing at 50 ° C. for 14 days with light shielding. By measuring the ink viscosity after being left with respect to the ink viscosity before being left, the ink thickening rate before and after being left was calculated, and thereby the storage stability of the ink was evaluated.
The evaluation criteria are as follows. ◎ and ○ are practically acceptable evaluation criteria. The evaluation results are shown in Table 5 below.
A: Less than 10%.
○: 10% or more and less than 20%.
X: 20% or more.

  From the above table, the number ratio of each polymerizable group in the polymerizable compound is within the range of 2 to 5 vinyl ether groups per N-vinyl group, and acryloyl groups per vinyl ether group. The ink composition (Example) in the range of 1.5 to 3.5 is more curable and adhesive than the ink composition (Comparative Example) that does not satisfy at least one of the above number ratios. And storage stability were found to be excellent.

  Specifically, the content of N-vinylcaprolactam (NVC) or N-vinylpyrrolidone (VP) (hereinafter referred to as “NVC etc.”) having only an N-vinyl group among the polymerizable compounds is relatively high. On the other hand, it was found that an ink composition having a relatively small content of 2- (2-vinyloxyethoxy) ethyl acrylate (VEEA) having only a vinyl ether group among polymerizable compounds is superior in adhesion. .

  Contrary to the above, it has been found that an ink composition having a relatively low content of NVC and the like and a relatively high content of VEEA is superior in storage stability.

  Further, it was found that an ink composition having a relatively large content of NVC or the like and VEEA is superior in curability.

  Furthermore, between Examples 4 to 7 and 11 to 14, the ink composition in which the number ratio of N-vinyl groups is in the range of 1.5 to 3.05 with respect to the photocleavable part 1 in the photopolymerization initiator The products (Examples 4, 5, 11, 12) were found to be more excellent in adhesion and storage stability than the ink compositions (Examples 6, 7, 13, 14) which were outside the range.

Claims (8)

An ultraviolet curable ink-jet ink composition comprising a polymerizable compound and a photopolymerization initiator,
The polymerizable compound contains, as a polymerizable group, an N-vinyl group, a vinyl ether group, and a (meth) acryloyl group,
As the polymerizable group present in the ink composition, the number ratio of the vinyl ether group is in the range of 2 to 5 with respect to one N-vinyl group, and the (meth) acryloyl group. The UV curable inkjet ink composition has a number ratio of 1.5 to 3.5 with respect to one vinyl ether group.   2. The ultraviolet curable inkjet ink according to claim 1, wherein the number ratio of the N-vinyl group is in a range of 1.5 to 3.05 with respect to one photocleavage portion in the photopolymerization initiator. Composition.   The ultraviolet curable inkjet ink composition according to claim 1, wherein the polymerizable compound contains N-vinylcaprolactam. The polymerizable compound has the following general formula (I):
_{^{CH 2 = CR 1 -COOR 2 -O}} -CH = CH-R 3 ··· (I)
Wherein R ¹ is a hydrogen atom or a methyl group, R ² is a divalent organic residue having 2 to 20 carbon atoms, and R ³ is a hydrogen atom or a monovalent organic residue having 1 to 11 carbon atoms. Group.)
The ultraviolet curable inkjet ink composition of any one of Claims 1-3 containing the monomer represented by these.   The ultraviolet curable inkjet ink composition according to claim 4, wherein the monomer is 2- (vinyloxyethoxy) ethyl acrylate.   6. The ultraviolet curable inkjet ink composition according to claim 1, wherein the recording medium to which the ink composition adheres is a package substrate or a semiconductor substrate.   Curing of the package base material or semiconductor base material as a recording medium, and the ultraviolet curable inkjet ink composition according to any one of claims 1 to 6 recorded on the package base material or the semiconductor base material. A recorded matter comprising a thing.   A discharge step of discharging the ultraviolet curable inkjet ink composition according to any one of claims 1 to 6 onto a recording medium, and the discharged ink composition emits light in a range of 350 nm to 400 nm. A curing step of curing the ink composition by irradiating with ultraviolet light having a peak wavelength.