JP2012144681A - 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, storage stability, visibility and abrasion resistance.SOLUTION: The ultraviolet curing inkjet ink composition includes a polymerizable compound, a photopolymerization initiator and a polymerization inhibitor, wherein at least one of a phenolic polymerization inhibitor and phenothiazine is included as the polymerization inhibitor, in an amount of 0.1-1 mass% of the total mass of the ink composition. The ultraviolet-curable inkjet ink composition is used for recording on a package substrate or a semiconductor substrate as a recording medium, and adheres to the package substrate or the semiconductor substrate, cures and is heat-treated at ≥150°C.

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 ink attached to an electronic component 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, any of the techniques disclosed in Patent Documents 1 to 6 is inferior to at least one of ink curability and storage stability, recorded image visibility, and cured product rubbing resistance. Or there is room for improvement. Therefore, the conventional marking method has a problem that it is difficult to apply it to a precise electronic component.

  Accordingly, the object of the present invention is to provide an ultraviolet curable inkjet ink composition excellent in curability, storage stability, visibility, and abrasion resistance, a recorded matter using the same, and an inkjet recording method. One.

  The present inventors have intensively studied to solve the above problems. When a precise electronic component is marked by a conventional marking method, the cured product of the ink recorded on the electronic component is inferior in abrasion resistance and cannot be practically used.

  Under such circumstances, when the kind and content of the polymerization inhibitor in the ink composition to be cured are predetermined, and the cured product is further heat-treated at a high temperature, the abrasion resistance is extremely excellent. The present inventors have found that a method for marking an electronic component that can sufficiently withstand practical use is obtained.

  In this way, the ultraviolet curable ink-jet ink includes a polymerizable compound, a photopolymerization initiator, a polymerization inhibitor having a predetermined type and a predetermined content, and is cured by heat treatment under predetermined conditions after being cured. A composition (hereinafter, also simply referred to as “ink composition”) can be suitably recorded (marked) on a package substrate or a semiconductor substrate of an electronic component, and the curability and storage stability of the ink. The present invention was completed by finding out that both the visibility of the recorded image and the rub resistance of the cured product were excellent.

That is, the present invention is as follows.
[1]
An ultraviolet curable inkjet ink composition comprising a polymerizable compound, a photopolymerization initiator, and a polymerization inhibitor, wherein at least one of a phenol polymerization inhibitor and phenothiazine is used as the polymerization inhibitor in the ink composition. 0.1 to 1% by mass based on the total mass, used for recording on a package substrate or semiconductor substrate as a recording medium, and attached to the package substrate or semiconductor substrate; An ultraviolet curable inkjet ink composition that is cured and heat-treated at 150 ° C. or higher.
[2]
The ultraviolet curable inkjet ink composition according to [1], wherein the viscosity at 20 ° C. is 10 to 25 mPa · s.
[3]
The ultraviolet curable inkjet ink composition according to [1] or [2], which is used for recording a pattern having a character size of 0.6 mm or less.
[4]
Any of [1] to [3], wherein the polymerizable compound contains N-vinylcaprolactam, and the content of the N-vinylcaprolactam is 5 to 15% by mass with respect to the total mass of the ink composition. An ultraviolet curable ink composition for inkjet according to the item 1.
[5]
The polymerizable compound includes a polyfunctional acrylate having a pentaerythritol skeleton,
The ultraviolet curable inkjet according to any one of [1] to [4], wherein the content of the polyfunctional acrylate having the pentaerythritol skeleton is 5 to 20% by mass with respect to the total mass of the ink composition. Ink composition.
[6]
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 [5] recorded on the package base material or the semiconductor base material A recorded matter comprising a thing.
[7]
The ultraviolet curable inkjet ink composition according to any one of [1] to [6], wherein the ink composition can be cured by irradiating ultraviolet rays having an emission peak wavelength in a range of 360 to 420 nm.
[8]
An adhesion step of adhering an ultraviolet curable ink jet ink composition to a package substrate or a semiconductor substrate, a curing step of irradiating the adhered ink composition with ultraviolet rays to cure the ink composition, and curing A heating step of heating the cured product obtained at 150 ° C. or higher,
The ultraviolet ray curable inkjet ink composition comprises a polymerizable compound, a photopolymerization initiator, and a polymerization inhibitor, and the polymerization inhibitor is selected from among phenolic polymerization inhibitors and phenothiazines. The inkjet recording method which contains 0.1 to 1 mass% of 1 or more types with respect to the gross mass of this ink composition.

  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 ink is recorded on a substrate to form a cured product. 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. “Abrasion resistance” refers to the property that when the cured product is scratched, the cured product is difficult to peel off from the package substrate or the like. “Storage stability” refers to the property that the viscosity is difficult to change before and after storage. “Discharge stability” refers to the property of ejecting stable ink droplets from the nozzles without clogging the nozzles.

  In this specification, “(meth) acrylate” means at least one of acrylate and its corresponding methacrylate, and “(meth) acryl” means at least one of acryl and its corresponding methacryl.

  In this specification, “character size” means the maximum length of a character. In this specification, this character size is measured in accordance with JISZ8305-1963 (standard size of type used for general printing), and the larger value of the size and width of the type is adopted.

[UV-curable inkjet ink composition]
One embodiment of the present invention relates to an ultraviolet curable inkjet ink composition. The ink composition includes a polymerizable compound, a photopolymerization initiator, a predetermined type and a polymerization inhibitor whose type is a predetermined amount. Further, the ink composition is subjected to heat treatment under a predetermined temperature condition after being cured. Furthermore, the ink composition has a feature that it is suitable for use in recording on a package substrate or a semiconductor substrate as a recording medium.

  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.

(N-vinylcaprolactam)
The polymerizable compound in the present embodiment preferably contains N-vinylcaprolactam. When the ink composition contains N-vinylcaprolactam as a polymerizable compound, the curability and storage stability of the ink and the rub resistance of the cured product can be improved.

  The content of N-vinylcaprolactam is preferably 5 to 15% by mass and more preferably 7 to 15% by mass with respect to the total mass (100% by mass) of the ink composition. When the content of N-vinylcaprolactam is within the above range, the curability and storage stability of the ink and the rub resistance of the cured product are excellent.

(Compound having a pentaerythritol skeleton)
The polymerizable compound in the present embodiment preferably contains one or more compounds having a pentaerythritol skeleton (C (CH ₂ O—) ₄ ).
When the ink composition contains a compound having a pentaerythritol skeleton as the polymerizable compound, it is possible to improve the rub resistance particularly in the cured ink.

  As compounds having a pentaerythritol skeleton, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, pentaerythritol ethoxytetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate And (meth) acrylate compounds such as polypentaerythritol poly (meth) acrylate, oxetanes such as pentaerythritol tris (3-ethyl-3-oxetanylmethyl) ether and pentaerythritoltetrakis (3-ethyl-3-oxetanylmethyl) ether And at least one of these compounds and ethylene oxide (EO) adducts and propylene oxide (PO) adducts. It is.

  Among these, polyfunctional (meth) acrylates having a pentaerythritol skeleton are preferable, and polyfunctional acrylates having a pentaerythritol skeleton are more preferable. Among polyfunctional (meth) acrylates having a pentaerythritol skeleton, at least one of pentaerythritol tri (meth) acrylate and pentaerythritol tetra (meth) acrylate is preferable, and at least any of pentaerythritol triacrylate and pentaerythritol tetraacrylate Are more preferable, and pentaerythritol triacrylate is more preferable. In the above case, the viscosity of the ink decreases and the crosslink density in the ink increases.

  The compound having a pentaerythritol skeleton is preferably contained in an amount of 5 to 20% by mass and more preferably 10 to 20% by mass with respect to the total mass (100% by mass) of the ink composition. When the content of the compound having a pentaerythritol skeleton is within the above range, the recorded image is more visible and the cured ink has better abrasion resistance.

(Compound having both vinyl and (meth) acryl groups in the molecule)
The ink composition of the present embodiment may contain a compound represented by the following general formula (I) (hereinafter referred to as “monomer A”).
_{^{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 monomer A is a compound having both a vinyl group and a (meth) acryl group in the molecule, and can be rephrased as vinyl ether group-containing (meth) acrylic acid esters.
When the ink composition contains the monomer A, the ink curability and the like can be 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 it also has low odor and suppresses irritation to the skin. In addition, 2- (vinyloxyethoxy) ethyl acrylate is more preferable because it is excellent in reactivity and adhesion.

  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.

  Monomer A may be used individually by 1 type, and may be used in combination of 2 or more type.

  The content of the monomer A is preferably 20 to 50% by mass with respect to the total mass (100% by mass) of the ink composition. When the content of the monomer A is within the above range, the rub resistance in the cured ink can be improved.

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 Salts 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.

(Polymerizable compounds other than the above)
As the polymerizable compound other than the above (hereinafter, referred to as “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 (meth) acrylic acid, itaconic acid, crotonic acid, isocrotonic acid and maleic acid, salts or esters thereof, urethane, amide and anhydride thereof, acrylonitrile, styrene, various types Unsaturated polyesters, unsaturated polyethers, unsaturated polyamides, and unsaturated urethanes. Examples of the oligomer include oligomers formed from the above monomers such as linear acrylic oligomers, epoxy (meth) acrylate, oxetane (meth) acrylate, aliphatic urethane (meth) acrylate, and aromatic urethane (meth). Acrylate and polyester (meth) acrylate are mentioned.

  Moreover, N-vinyl compounds other than N-vinylcaprolactam may be included as another monofunctional monomer or polyfunctional monomer. Examples of such N-vinyl compounds include N-vinylformamide, N-vinylcarbazole, N-vinylacetamide, N-vinylpyrrolidone, and acryloylmorpholine, and derivatives thereof.

  Among other polymerizable compounds, an ester of (meth) acrylic acid, that is, (meth) acrylate is preferable, polyfunctional (meth) acrylate having 2 or more functions is more preferable, and polyfunctional acrylate is more preferable.

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 these, in order to reduce viscosity and odor, at least one of phenoxyethyl (meth) acrylate and isobornyl (meth) acrylate is preferable, phenoxyethyl (meth) acrylate is more preferable, and phenoxyethyl acrylate is more preferable.

  Among the (meth) acrylates, examples of the polyfunctional (meth) acrylate include triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, and tripropylene glycol di ( (Meth) acrylate, polypropylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, neopentyl Glycol di (meth) acrylate, dimethylol-tricyclodecane di (meth) acrylate, di (meth) acrylate of bisphenol A, neopentyl glycol di (meth) acrylate of hydroxypivalate, and poly Bifunctional (meth) acrylates such as tetramethylene glycol di (meth) acrylate, as well as trimethylolpropane tri (meth) acrylate, glycerin propoxytri (meth) acrylate, cowprolactone modified trimethylolpropane tri (meth) acrylate, ditri Methylolpropane tetra (meth) acrylate, sorbitol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, caprolactam modified dipentaerythritol hexa (meth) acrylate, dipentaerythritol penta (meth) acrylate, and caprolactone modified dipentaerythritol (Meth) acrylate having dipentaerythritol skeleton such as hexa (meth) acrylate, propionic acid modified tripenta (Meth) acrylates having a tripentaerythritol skeleton such as lithitolitol penta (meth) acrylate, tripentaerythritol hexa (meth) acrylate, tripentaerythritol hepta (meth) acrylate, and tripentaerythritol octa (meth) acrylate, tetrapenta Erythritol penta (meth) acrylate, tetrapentaerythritol hexa (meth) acrylate, tetrapentaerythritol hepta (meth) acrylate, tetrapentaerythritol octa (meth) acrylate, tetrapentaerythritol nona (meth) acrylate, tetrapentaerythritol nona (meth) Tetrapentaerythritol bone such as acrylate and tetrapentaerythritol deca (meth) acrylate (Meth) acrylates having a pentapentaerythritol skeleton, such as (meth) acrylates having a rating, pentapentaerythritol undeca (meth) acrylate and pentapentaerythritol dodeca (meth) acrylate, and ethylene oxide (EO) adducts thereof Trifunctional or higher functional (meth) acrylates such as at least one of propylene oxide (PO) adducts may be mentioned.

  Among these, since the abrasion resistance in the cured ink can be improved, (meth) acrylate having a dipentaerythritol skeleton, (meth) acrylate having a tripentaerythritol skeleton, and a tetrapentaerythritol skeleton ( One or more selected from the group consisting of (meth) acrylate, (meth) acrylate having a pentapentaerythritol skeleton, and polypentaerythritol poly (meth) acrylate are preferred.

  The said other polymeric compound may be used individually by 1 type, and may use 2 or more types together.

(Photopolymerization initiator)
The photopolymerization initiator contained in the ink composition of the present embodiment is excellent in safety and can reduce the cost of the light source. Therefore, the ink existing on the surface of the recording medium by photopolymerization by ultraviolet irradiation. Is used to form an image. 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 the polymerization of the polymerizable compound. A polymerization initiator can be used, and among these, it is preferable to use a radical photopolymerization 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, since the curability of the ink can be further improved, at least one of an acyl phosphine oxide compound and a thioxanthone compound is preferable, and an acyl phosphine oxide compound and a thioxanthone compound are more preferable.

  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- (2-hydroxyethoxy) ethyl ester mixture (above, BASF), Speedcure TPO (Lambson), KAYACURE DETX-S (2,4-diethylthioxanthone) (Nippon Kayaku Co., Ltd.), Lucirin TPO, LR8883, LR8970 (above BASF), and Yubek Examples include Lil P36 (manufactured by UCB).

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

  The photopolymerization initiator exhibits a sufficient radiation 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.

(Polymerization inhibitor)
The polymerization inhibitor contained in the ink composition of the present embodiment contains at least one of a phenol polymerization inhibitor and phenothiazine. Thereby, in addition to being able to suppress the polymerization reaction of the polymerizable compound before curing, it is excellent in the storage stability of the ink and the rub resistance of the cured product.

  Examples of the phenol polymerization inhibitor include, but are not limited to, for example, p-methoxyphenol, cresol, t-butylcatechol, di-t-butylparacresol, hydroquinone monomethyl ether, α-naphthol, 3,5-di- t-butyl-4-hydroxytoluene, 2,6-di-t-butyl-4-methylphenol, 2,2'-methylene-bis (4-methyl-6-t-butylphenol), 2,2'-methylene -Bis (4-ethyl-6-butylphenol) and 4,4'-thio-bis (3-methyl-6-tert-butylphenol).

  Of the above-mentioned phenolic polymerization inhibitors and phenothiazines, phenolic polymerization inhibitors are preferred in order to further improve the storage stability of the ink and the rub resistance of the cured product. Among these phenol polymerization inhibitors, p-methoxyphenol, 2,6-di-t-butyl-4-methylphenol, 2,2'-methylene-bis (4-methyl-6-t-butylphenol) One or more selected from the group consisting of

  Examples of commercially available phenolic polymerization inhibitors and phenothiazines include p-methoxyphenol (KANTO CHEMICAL CO., INC, trade name, p-methoxyphenol), non-flex MBP (Seiko Chemical Co., Ltd.). (Seiko Chemical Co., Ltd.) trade name, 2,2′-methylene-bis (4-methyl-6-tert-butylphenol)), BHT Swanox (trade name, 2,6-di-) manufactured by Seiko Chemical Co., Ltd. t-butyl-4-methylphenol) and phenothiazine (trade name, manufactured by Seiko Chemical Co., Ltd., phenothiazine).

  A polymerization inhibitor may be used individually by 1 type, and may be used in combination of 2 or more type.

  The content of one or more of the phenol-based polymerization inhibitor and phenothiazine as the polymerization inhibitor is 0.1 to 1% by mass, and 0.15 to 0% with respect to the total mass (100% by mass) of the ink composition. It is preferably 4% by mass. When the content is 0.1% by mass or more, it can withstand use and has excellent storage stability of the ink. In addition, as described below, it is cured by heating at a high temperature after curing. Since it is presumed that the polymerization inhibitor can prevent damage that the product can receive, the rub resistance of the cured product can be further improved. Further, when the content is 1% by mass or less, the curability of the ink and the visibility of the recorded image can be further improved.

[Color material]
The ink composition of this embodiment may contain 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 the inorganic pigments, titanium oxide is preferable because it exhibits a preferable white color.

  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. (above, manufactured by CABOT JAPAN K. C. Black FW1, Color Black FW2, Color Black FW2V, Color Black FW18, Color Black FW200, Color B1ack S150, Color Black S160, Color Black S170, Printex 35, Printex U, Printex V, Printex 140U, Special Black 6S, Special Black S6, Color Black S170, Color Black S160, 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 use 2 or more types together.

  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 use 2 or more types together.

  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 can be obtained.

  In particular, the content of titanium oxide in the coloring material is preferably 12 to 18% by mass with respect to the total mass (100% by mass) of the ink composition in order to ensure concealment on the black base material. More preferably, it is 14-16 mass%.

[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, Solspers series (Solsperse 36000, etc.) available from Noveon, BYK Dispersic series, Enomoto Kasei Co., Ltd. Disparon series is mentioned.

[Surfactant]
The ink composition of the present embodiment may contain a surfactant because it can improve the abrasion resistance of the cured ink. The surfactant is not particularly limited. For example, polyester-modified silicone or polyether-modified silicone can be used as the silicone-based surfactant, and polyether-modified polydimethylsiloxane or polyester-modified polydimethylsiloxane can be used. Particularly preferred. Specific examples include BYK-347, BYK-348, BYK-UV3500, 3510, 3530, and 3570 (above, trade names 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.

[Physical properties of ink composition]
The viscosity of the ink composition of the present embodiment at 20 ° C. is preferably 10 to 25 mPa · s or less, and more preferably 15 to 20 mPa · s. When the viscosity is within the above range, the ink ejection stability is good.

[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. That is, the ink composition is suitable for use in recording on a package substrate or the like as a recording medium. This is because the ink used for marking on the package substrate and the like is required to have excellent curability and storage stability, and the cured product obtained by curing the ink has excellent visibility and resistance. This is because rubbing properties are required.
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 the visibility and abrasion resistance of hardened | cured material, as a package base material, a silicone or an epoxy resin is more preferable. Thus, by using a package base material 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 base material. .

  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 visibility and abrasion resistance of a cured product, 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 silicone resin. Marking can be performed on the electronic component thus manufactured (outer surface).

  When the ink composition is applied to a non-absorbable recording medium, it may be necessary to provide a drying step after irradiating with ultraviolet rays.

As described above, according to the present embodiment, it is possible to provide an ultraviolet curable inkjet ink composition excellent in curability, storage stability, visibility, and abrasion resistance.
In addition, the ink composition of the present embodiment exhibits the excellent effects as described above, in combination with being subjected to heat treatment under a predetermined temperature condition after curing. This heat treatment will be described in detail in the section of the inkjet recording method described later.

[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 excellent in the curability and storage stability of the ink composition, and is excellent in the visibility of the ink composition (cured product) adhered and cured on a package substrate or the like, and the cured product is resistant to abrasion. It has the characteristic that it is excellent in property.

  As described above, according to the present embodiment, a recorded matter using the ultraviolet curable ink jet ink composition having excellent curability and storage stability and having excellent recorded image visibility and cured product rub resistance. Can be provided.

[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 light emission peak within a predetermined range on the ink composition discharged and adhered by the discharge step. It includes a curing step of irradiating ultraviolet rays having a wavelength to cure the ink composition, and a heating step of heating a cured product obtained by curing at 150 ° C. or higher. In this way, a cured product is formed from the ink composition that has been subjected to ultraviolet irradiation and heat treatment on the package substrate or the like. Hereafter, each said process is demonstrated in detail.

[Discharge process]
First, a conventionally known ink jet recording apparatus can be used in the ejection process. When discharging the ink composition, the viscosity of the ink composition is preferably 10 to 25 mPa · s as described above. 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 ejected and adhered 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 initiating species such as radicals, acids, and bases, and the polymerization reaction of the polymerizable compound is accelerated by the function of the initiating 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 ink compositions for radiation curable ink jets. . 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 life, have high efficiency, and are low in cost, and are expected as light sources for radiation-curable ink jets. Among these, UV-LED is preferable.

Here, the ink composition of the above embodiment can be cured by irradiating with ultraviolet rays having an emission peak wavelength in the range of 360 to 420 nm, preferably in the range of 365 to 395 nm. The irradiation energy is preferably 500 mJ / cm ² or less.

  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 recording 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. The present inventors have found that it is preferable to use a UV-LED for ultraviolet irradiation at that time. Such an ink composition is obtained by including a photopolymerization initiator that is decomposed by irradiation with ultraviolet rays in the wavelength range, and includes a polymerizable compound that starts polymerization by irradiation with ultraviolet rays in the wavelength range. Curing at high speed is possible. 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.

[Heating process]
Next, in the heating step, a heat treatment is performed on the cured product obtained by curing the ink composition through the curing step. By performing this heat treatment, low molecular components such as those in which the photopolymerization initiator is cleaved during the curing reaction to lower the molecular weight and unreacted polymerizable compounds can be volatilized from the cured product of the ink. As a result, the rub resistance of the cured product can be further improved.

  The heating temperature in the heat treatment is 150 ° C. or higher, and preferably 150 to 190 ° C. When the heating temperature is 150 ° C. or higher, the abrasion resistance can be excellent.

  As described above, according to the present embodiment, an inkjet using the ultraviolet curable inkjet ink composition that is excellent in both curability and storage stability, visibility of recorded images, and rub resistance of a cured product. A 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.
(Photopolymerization initiator)
IRGACURE 819 (trade name, manufactured by BASF, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, abbreviated 819 in Table 1)
DAROCURE TPO (trade name, manufactured by BASF, 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, abbreviated as TPO in Table 1)
[Pigment]
Tipaque (registered trademark) CR-60-2 (trade name, titanium oxide, average particle size 0.21 μm, manufactured by ISHIHARA SANGYO KAISHA, LTD., Abbreviated as Ti oxide in Table 1)
[Dispersant]
・ Solsperse 36000 (Noveon product name)
(Polymerization inhibitor)
P-methoxyphenol (KANTO CHEMICAL CO., INC, trade name, abbreviated as MEHQ in Table 1)
Non-flex MBP (trade name, 2,2′-methylene-bis (4-methyl-6-tert-butylphenol) manufactured by Seiko Chemical Co., Ltd., abbreviated as MBP in Table 1)
BHT Swanox (trade name, 2,6-di-t-butyl-4-methylphenol, manufactured by Seiko Chemical Co., Ltd., abbreviated as BHT in Table 1)
・ Phenothiazine (trade name, manufactured by Seiko Chemical Co., Ltd.)
FA-711MM (trade name, pentamethylpiperidyl methacrylate, manufactured by Hitachi Chemical Co., Ltd.)
[Surfactant]
BYK-UV3500 (trade name, polysiloxane, both ends, BYK-Chemie, manufactured by BYK-Chemie, abbreviated as BYK3500 in Table 1)
(Polymerizable compound)
VEEA (2- (2-vinyloxyethoxy) ethyl acrylate, trade name of Nippon Shokubai Co., Ltd., abbreviated as VEEA in Table 1)
V-CAP (N-vinylcaprolactam, trade name of ISP company, abbreviated as NVC in Table 1)
Biscoat # 192 (phenoxyethyl acrylate, trade name of Osaka Organic Chemical Industry Co., Ltd., abbreviated as PEA in Table 1)
SR-444 (pentaerythritol triacrylate, trade name of Sartomer Co., abbreviated as PETA in Table 1)

〔Base material〕
Base material 1 (package base material): Epoxy resin surface (manufactured by Sharp Corporation, surface mount package, model number “P-LFBGA048-0606”)
・ Substrate 2 (semiconductor substrate): Silicon surface (SUMCO, SOI wafer)
Base material 3 (other base materials): Lumirror (registered trademark) E20 # 125 (trade name, manufactured by Toray Industries, Inc., biaxially stretched polyester (PET) film, white grade, thickness 125 μm)
Base material 4 (other base materials): Viroflex (registered trademark) (trade name, 2-layer flexible copper-clad laminate (copper surface) manufactured by TOYOBO CO.LTD.)
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 to 15]
(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 listed in Table 1 below were added so as to have the composition (unit: mass%) described in Table 1 (in Table 1, the pigment and a part of VEEA were added as the pigment dispersion). The mixture was mixed and stirred at room temperature for 1 hour for complete dissolution. This was further filtered through a 5 μm membrane filter to obtain each ultraviolet curable ink composition for inkjet.

  In Table 1, the dispersant in the pigment dispersion is not described because its composition can be calculated on the basis of the solid content of the pigment and VEEA. In the ink composition, Examples 1 to 11 correspond to Examples, and Examples 12 to 15 correspond to Comparative Examples.

[Measurement / Evaluation Items]
About the ultraviolet curable inkjet ink composition prepared in Examples 1 to 15 above, the viscosity, curability, storage stability, visibility, and abrasion resistance were evaluated by the following methods.

〔viscosity〕
The viscosity of each ink composition was measured using an E-type viscometer (manufactured by Toki Sangyo Co., Ltd.) at a temperature of 20 ° C. and a rotation speed of 10 rpm. The measurement results are shown in Table 2 below.

[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 2 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.

[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 2 below.
A: Less than 10%,
○: 10% or more and less than 20%,
X: 20% or more.

〔Visibility〕
Using the inkjet printer PX-G5000 (trade name, manufactured by Seiko Epson Corporation), each of the above ink compositions was filled in each nozzle row. Under the conditions of a recording resolution of 720 dpi × 720 dpi and a droplet weight of 7 ng, letters “A” of various sizes were printed on the substrates 1 to 4 at normal temperature and normal pressure.
Along with this printing, from the UV-LED in the ultraviolet irradiation device mounted on the side of the carriage, irradiation with ultraviolet rays having an irradiation intensity of 400 mW / cm ² and a wavelength of 395 nm is performed at 600 mJ / cm ² to form the above character pattern. Cured.
As described above, recorded matter in which the letter “A” was recorded on each of the substrates 1 to 4 was produced. The evaluation was performed from the viewpoint of whether the Δ part in the character can be identified. The evaluation criteria are as follows. ◎ and ○ are practically acceptable evaluation criteria. The evaluation results are shown in Table 2 below.
A: Character size of 0.3 mm or less can be identified.
○: A character size of 0.3 mm or less cannot be identified, but a character size exceeding 0.3 mm and 0.8 mm or less can be identified.
X: A character size of 0.8 mm or less cannot be identified, but a character size larger than 0.8 mm can be identified.

  In addition, among the visibility in the said Table 2, the case where it prints on the base materials 1 and 2 of Examples 1-11 corresponds to an Example, and the base materials 3 and 4 of Examples 1-11 (a package base material, a semiconductor substrate) In the case of printing on a base material that is not any of the materials, Examples 12 to 15 correspond to comparative examples.

[Abrasion resistance]
Except that the character image A (character size 0.6 mm) was printed instead of the solid pattern image, the printing and curing similar to the evaluation items of the curability and the heat treatment under various conditions were performed on the base materials 1 to 1. 4 was performed. And the peeling degree of the cured film (coating film) was confirmed using the load fluctuation type friction abrasion test system (Tribogear TYPE-HHS2000 [trade name], manufactured by Shinto Kagaku Co., Ltd.). The condition was that the load was set to 150 gf, the letter image after the heat treatment was scratched with a Φ0.2 mm sapphire needle (however, the letter image after curing for a system that was not heated), and the degree of peeling of the coating film was confirmed .
The evaluation criteria are as follows. ◎ and ○ are practically acceptable evaluation criteria. The evaluation results are shown in Tables 3 to 5 below.
A: There are no scratches or peeling on the coating surface.
○: The coating surface is scratched. There is no peeling.
X: The coating surface is scratched and the coating is peeled off.

  In Table 3 above, all examples correspond to comparative examples in that no heat treatment is performed after curing.

  In Table 4 above, all examples correspond to comparative examples in terms of heating temperature.

  In Table 5, the case where printing is performed on the substrates 1 and 2 of Examples 1-3 to 11-3 corresponds to Examples, and the substrates 3 and 4 of Examples 1-3 to 11-3 (package bases). In the case of printing on a substrate that is neither a material nor a semiconductor substrate, Examples 12-3 to 15-3 correspond to comparative examples.

  From the said Tables 2-5, it contains a polymeric compound, a photoinitiator, and a polymerization inhibitor, The said polymerization inhibitor contains at least any one among a phenolic polymerization inhibitor and a phenothiazine, And the said polymerization inhibitor UV curable inkjet ink compositions (Examples 1 to 11 above) having a content of 0.1 to 1% by mass with respect to the total mass of the ink composition are package substrates and the like (the above substrates 1 and 2). ) The image recorded above was found to be excellent in all of curability, storage stability, and visibility. In addition to this, it was found that the ink adhered to the package base material and the like was cured and heat-treated at 150 ° C. or more (Table 5 above) had excellent abrasion resistance.

  The polymerization inhibitor will be considered in detail. Ink compositions containing at least one of phenolic polymerization inhibitors and phenothiazines as polymerization inhibitors (Examples 1 to 11 above) are ink compositions containing a polymerization inhibitor other than phenolic polymerization inhibitors and phenothiazines ( It was found that the storage stability was particularly excellent as compared with Example 14).

  When the polymerization inhibitor contains at least one of a phenol polymerization inhibitor and phenothiazine, the content of the polymerization inhibitor is within a range of 0.1 to 1% by mass with respect to the total mass of the ink composition. It was found that a certain ink composition (Examples 1 to 11 above) was excellent in storage stability and abrasion resistance as compared with an ink composition (Example 12 above) below this range. On the other hand, it was found that the ink compositions of Examples 1 to 11 were excellent in curability as compared with ink compositions exceeding the above ranges (Examples 13 and 15 above).

  Of the above, regarding the scratch resistance, the ink composition adhered to and cured on the package substrate or the like is heat-treated at 150 ° C. or more, whereby the scratch resistance becomes excellent (see Tables 3 to 3 above). 5). The reason for this is that when heated at a high temperature of 150 ° C. or higher, the cured product can suffer as much damage as the abrasion resistance deteriorates, but when the polymerization inhibitor is present in the cured product, the polymerization inhibitor prevents the damage. This is presumed.

  Further, according to Examples 10 and 11 and other examples (especially Examples 6 and 7), among the polymerizable compounds, N-vinylcaprolactam (NVC) improves the film quality when heated at 150 ° C., but specific polymerization is prohibited. When the content of the agent (at least one of a predetermined content of the phenol polymerization inhibitor and phenothiazine) is not too small relative to NVC, the storage stability becomes better and the abrasion resistance becomes higher. On the other hand, when the content of the specific polymerization inhibitor is not too large relative to NVC, in addition to good storage stability and abrasion resistance, curability is also improved. Therefore, from the results of Examples 6, 7, 10, and 11, it was also found that there is a preferable range for the content of NVC in relation to the specific polymerization inhibitor. Specifically, in the ink composition, the NVC content is 5 to 15% by mass with respect to the polymerization inhibitor content of 0.1 to 1% by mass.

Claims (8)

An ultraviolet curable ink-jet ink composition comprising a polymerizable compound, a photopolymerization initiator, and a polymerization inhibitor,
0.1 to 1% by mass of one or more of a phenolic polymerization inhibitor and phenothiazine as the polymerization inhibitor with respect to the total mass of the ink composition;
Used for recording on a package substrate or a semiconductor substrate as a recording medium, and
An ultraviolet curable inkjet ink composition that adheres to the package substrate or the semiconductor substrate, cures, and is heat-treated at 150 ° C. or higher.   The ultraviolet curable inkjet ink composition according to claim 1, wherein the viscosity at 20 ° C. is 10 to 25 mPa · s.   The ultraviolet curable inkjet ink composition according to claim 1 or 2, which is used for recording a pattern having a character size of 0.6 mm or less. The polymerizable compound includes N-vinylcaprolactam,
The ultraviolet curable inkjet ink composition according to any one of claims 1 to 3, wherein a content of the N-vinylcaprolactam is 5 to 15 mass% with respect to a total mass of the ink composition. The polymerizable compound includes a polyfunctional acrylate having a pentaerythritol skeleton,
5. The ultraviolet curable inkjet according to claim 1, wherein the content of the polyfunctional acrylate having the pentaerythritol skeleton is 5 to 20% by mass with respect to the total mass of the ink composition. Ink composition.   Curing of a package base material or a semiconductor base material as a recording medium, and the ultraviolet curable inkjet ink composition according to any one of claims 1 to 5 recorded on the package base material or the semiconductor base material. A recorded matter comprising a thing.   The ultraviolet curable inkjet ink composition according to any one of claims 1 to 6, wherein the ink composition can be cured by irradiating ultraviolet rays having an emission peak wavelength in a range of 360 to 420 nm. An adhesion step of adhering the ultraviolet curable inkjet ink composition to a package substrate or a semiconductor substrate;
A curing step of curing the ink composition by irradiating the deposited ink composition with ultraviolet rays;
A heating step of heating a cured product obtained by curing at 150 ° C. or higher;
An inkjet recording method comprising:
The ultraviolet curable ink composition for inkjet includes a polymerizable compound, a photopolymerization initiator, and a polymerization inhibitor, and at least one of a phenol polymerization inhibitor and a phenothiazine as the polymerization inhibitor is a total of the ink composition. An inkjet recording method containing 0.1 to 1% by mass with respect to mass.