JP6429679B2 - UV curable adhesive composition - Google Patents

Description

  The present invention relates to an ultraviolet curable adhesive composition.

  In recent years, ultraviolet curable adhesive compositions have been widely used in various fields from the viewpoints of energy saving and excellent productivity. Ultraviolet curable adhesive compositions have come to be used in the production of display-related pressure-sensitive adhesive films, semiconductor wafer dicing tapes, and labels.

  In general, when used as a pressure-sensitive adhesive, from the viewpoint of tackiness and compatibility with a tackifier, the monofunctional acrylate compound is mainly composed of alkyl (meth) acrylates having an alkyl group having 2 to 12 carbon atoms. There are many cases.

  As the tackifier, tackifiers such as rosin resin, rosin ester resin, petroleum resin, terpene resin, and terpene phenol resin are often used. In particular, in the case of an acrylic resin composition, a rosin resin and a rosin ester resin are suitably used because of good compatibility.

  Prior Document 1 discloses photopolymerization with respect to 100 parts by weight of active energy ray-curable monomer (a) containing 50% by weight or more of (meth) acrylic acid alkyl ester having an alkyl group having 2 to 12 carbon atoms. An active energy ray-curable pressure-sensitive adhesive composition containing 0.01 to 5 parts by weight of an initiator (b), comprising 2 to 30 parts by weight of a hydrogenated rosin resin (c) having a softening point of 115 ° C. or higher. A line-curable pressure-sensitive adhesive composition is disclosed.

Japanese Patent No. 5370811

  However, polymers obtained by polymerizing (meth) acrylic acid alkyl esters having an alkyl group having 2 to 12 carbon atoms are flexible and suitable for pressure-sensitive adhesives, but are non-polar materials, so sufficient adhesion Sex cannot be obtained.

  Further, (meth) acrylic acid alkyl esters having an alkyl group having 2 to 12 carbon atoms are easy to evaporate, have strong odor, and are inferior in handleability. Therefore, in some fields, monofunctional acrylate compounds other than (meth) acrylic acid alkyl esters having an alkyl group having 2 to 12 carbon atoms are used. Since the compatibility of is not good, another problem arises in that it becomes cloudy after ultraviolet irradiation.

  The present invention provides an ultraviolet curable adhesive composition that has little odor, exhibits excellent tackiness by curing with ultraviolet irradiation, and is transparent even after ultraviolet curing.

  The ultraviolet curable adhesive composition of the present invention has a viscosity at 25 ° C. of 50 mPa · s or more and a monofunctional acrylate compound containing an aromatic ring of 100 parts by mass, a rosin acrylate compound of 5 parts by mass or more, and a softening point of 75 ° C. It contains 10 to 90 parts by mass of the above tackifier and an ultraviolet polymerization initiator.

  The ultraviolet curable adhesive composition contains a monofunctional acrylate compound having a viscosity at 25 ° C. of 50 mPa · s or more and containing an aromatic ring.

  The viscosity at 25 ° C. of the monofunctional acrylate compound is 50 mPa · s or more, preferably 100 mPa · s or more, and more preferably 150 mPa · s or more, because it can suppress transpiration and suppress odor. The viscosity at 25 ° C. of the monofunctional acrylate compound is preferably 2000 mPa · s or less, more preferably 1000 mPa · s or less, and more preferably 500 mPa · s or less, because the UV curable adhesive composition is excellent in tackiness after curing. Particularly preferred. The viscosity at 25 ° C. of the monofunctional acrylate compound is a value measured using a BM viscometer at 25 ° C. in accordance with JIS K7111-1: 1999. In addition, No. Measurement is performed using the rotor of No. 2.

  The monofunctional acrylate compound contains an aromatic ring in the molecule. When the monofunctional acrylate compound contains an aromatic ring in the molecule, the ultraviolet curable adhesive composition exhibits excellent tackiness after curing. Examples of the aromatic ring include a benzene ring and a naphthalene ring, and a benzene ring is preferable.

  Since the monofunctional acrylate compound is excellent in the tackiness of the cured ultraviolet curable adhesive composition, it preferably has a polar group in the molecule. As such a polar group, a hydroxyl group and a carboxy group are preferable, and a hydroxyl group is more preferable.

  The monofunctional acrylate compound is not particularly limited as long as the viscosity at 25 ° C. is 50 mPa · s or more and contains an aromatic ring. For example, 2-acryloyloxyethyl phthalate, 2-acryloyloxyethyl-2- Examples include hydroxyethyl phthalate, 2-acryloyloxypropyl phthalate, neopentyl glycol benzoate acrylate, paracumyl phenoxyethylene glycol acrylate, 3-phenoxy-2-hydroxypropyl acrylate, and 3-phenoxy-2-hydroxypropyl acrylate, 2 -Acryloyloxyethyl phthalate, neopentyl glycol benzoate acrylate are preferred. In addition, a monofunctional acrylate compound may be used independently or 2 or more types may be used together.

  In addition, since it becomes a cause of the fall of the adhesiveness after hardening, and the handleability fall by an odor in an ultraviolet curable adhesive composition, it is preferable not to contain (meth) acrylic-acid alkylester.

  The ultraviolet curable adhesive composition contains a rosin acrylate compound. The rosin acrylate compound has low transpiration and can suppress odor. Furthermore, the ultraviolet curable adhesive composition after ultraviolet curing can be kept transparent by containing the rosin acrylate compound.

  Examples of the rosin acrylate compound include an ester compound of a compound having a rosin skeleton and a (meth) acrylate compound having a hydroxyl group, or a reaction product of a compound having a rosin skeleton and a (meth) acrylate compound having a glycidyl group. An ester compound with a (meth) acrylate compound having a hydroxyl group is preferred.

  Examples of the compound having a rosin skeleton include unmodified rosin (such as tall rosin, gum rosin, and wood rosin), polymerized rosin, disproportionated rosin, hydrogenated rosin, maleic acid modified rosin, fumaric acid modified rosin, and esters thereof ( Examples thereof include glycerin ester, pentaerythritol ester, methyl ester, ethyl ester, butyl ester, and ethylene glycol ester. In addition, the compound which has a rosin skeleton may be used independently, or 2 or more types may be used together.

  The (meth) acrylate compound having a hydroxyl group is not particularly limited, and examples thereof include 2-hydroxyethyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, and 1,2-dihydroxyethyl (meth) acrylate. 1,2-dihydroxyethyl (meth) acrylate is preferred, and 1,2-dihydroxyethyl acrylate is more preferred. The (meth) acrylate compound having a hydroxyl group may be used alone or in combination of two or more. It does not specifically limit as a (meth) acrylate compound which has a glycidyl group, For example, a glycidyl (meth) acrylate etc. are mentioned. The (meth) acrylate compound having a glycidyl group may be used alone or in combination of two or more. In addition, (meth) acrylate means an acrylate or a methacrylate.

  As the rosin acrylate compound, a compound represented by the formula (1) is preferable.

  The viscosity at 40 ° C. of the rosin acrylate compound is preferably 10,000 to 300,000 mPa · s, and more preferably 50,000 to 200,000 mPa · s. When the viscosity at 40 ° C. of the rosin acrylate compound is within the above range, the transpiration is lower and the odor can be further suppressed. Furthermore, by containing the rosin acrylate compound having such a viscosity, it becomes easier to keep the UV-curable adhesive composition after UV curing transparent.

  The viscosity at 40 ° C. of the rosin acrylate compound is a value measured using a B-type viscometer at 40 ° C. in accordance with JIS K7111-1: 1999. In addition, No. Measurements are made using a 4-29 spindle.

  Content of the rosin acrylate compound in an ultraviolet curable adhesive composition is 5 mass parts or more with respect to 100 mass parts of monofunctional acrylate compounds, 10 mass parts or more are preferable and 15 mass parts or more are more preferable. When the content of the rosin acrylate compound is 5 parts by mass or more, the compatibility between the monofunctional acrylate compound and the tackifier is improved, the transparency of the UV curable adhesive composition after UV curing is improved, and UV curing is achieved. The later UV curable adhesive composition exhibits excellent tackiness. The content of the rosin acrylate compound in the ultraviolet curable adhesive composition is preferably 150 parts by mass or less, more preferably 100 parts by mass or less, and particularly preferably 50 parts by mass or less with respect to 100 parts by mass of the monofunctional acrylate compound. When the content of the rosin acrylate compound is 150 parts by mass or less, the ultraviolet curable adhesive composition after ultraviolet curing exhibits excellent tackiness.

  The ultraviolet curable adhesive composition contains a tackifier having a softening point of 75 ° C. or higher. The softening point of the tackifier gives an appropriate hardness to the UV-curable adhesive composition after UV curing, and the UV-curable adhesive composition exhibits excellent tackiness, so it is 75 ° C or higher. 75-110 degreeC is preferable and 80-110 degreeC is more preferable. In addition, the softening point of a tackifier means the temperature measured based on the 6.4 softening point test method prescribed | regulated to JISK2207 (petroleum asphalt).

  The tackifier is not particularly limited as long as the softening point is 75 ° C. or higher. For example, rosin tackifier, petroleum resin tackifier, terpene tackifier, phenol tackifier, styrene Examples include tackifiers, epoxy tackifiers, coumarone-indene tackifiers, polyamide tackifiers, elastomer tackifiers, naphthenic oil tackifiers, and ketone tackifiers, and rosin tack An imparting agent is preferred. In addition, a tackifier may be used independently or 2 or more types may be used together.

  Examples of the rosin-based tackifier include unmodified rosin (such as tall rosin, gum rosin, and wood rosin), polymerized rosin, disproportionated rosin, hydrogenated rosin, maleic acid modified rosin, fumaric acid modified rosin, and esters thereof ( The term “rosin ester” includes, for example, glycerin ester, pentaerythritol ester, methyl ester, ethyl ester, butyl ester, and ethylene glycol ester). The rosin-based tackifier has excellent compatibility with a monofunctional acrylate compound, and the UV curable adhesive composition exhibits better tackiness by UV curing, and the UV curable adhesive after UV curing Unmodified rosin, hydrogenated rosin, rosin ester, and hydrogenated rosin ester are preferred because they are superior in transparency of the composition.

  Examples of the petroleum resin tackifier include petroleum resins (for example, C5 petroleum resins, C9 petroleum resins, C5-C9 copolymer petroleum resins, and dicyclopentadiene petroleum resins), hydrogenated petroleum resins, and the like. It is done.

  Examples of the terpene tackifier include terpene resins (for example, α-pinene polymer, β-pinene polymer, and dipentene polymer), and modified terpene resins (for example, terpene phenol resin, styrene modified terpene resin, And hydrogenated terpene resins).

  Examples of the phenol tackifier include condensates of phenols (for example, phenol, m-cresol, 3,5-xylenol, p-alkylphenol, resorcin, etc.) and formaldehyde, resol type phenol resin, novolac type phenol resin, and Examples include rosin-modified phenolic resins.

  Examples of the styrene tackifier include styrene resins such as a styrene homopolymer, an α-methylstyrene homopolymer, and a styrene-α-methylstyrene copolymer.

  The content of the tackifier in the ultraviolet curable adhesive composition is 10 to 100 parts by mass of the monofunctional acrylate compound because the ultraviolet curable adhesive composition after the ultraviolet curing exhibits excellent tackiness. 90 mass parts is preferable and 20-70 mass parts is more preferable.

  The ultraviolet curable adhesive composition contains an ultraviolet polymerization initiator. The ultraviolet polymerization initiator is not particularly limited, and for example, an ultraviolet polymerization initiator such as benzophenone, alkylphenone, acylphosphine oxide, and titanocene is preferable.

  The UV polymerization initiator is excellent in compatibility with the monofunctional acrylate compound, the UV curable adhesive composition after UV curing exhibits excellent tackiness, and the UV curable adhesive composition after UV curing Therefore, benzophenone-based, alkylphenone-based and acylphosphine oxide-based ultraviolet polymerization initiators are preferable, and alkylphenone-based ultraviolet polymerization initiators are more preferable. The ultraviolet polymerization initiator is commercially available, for example, from BASF under the trade name “IRGACURE (registered trademark)”.

  Examples of the benzophenone-based ultraviolet polymerization initiator include benzophenone, 4-phenylbenzophenone, hydroxybenzophenone, benzoylbenzoic acid, methyl benzoylbenzoate, 4-benzoyl-4′-methyldiphenyl sulfide, and 3,3′-dimethyl-4. -Methoxybenzophenone and the like.

  Examples of the alkyl phenone-based ultraviolet polymerization initiator include 2,2-dimethoxy-1,2-diphenylethane-1-one, 1-hydroxy-cyclohexyl-phenyl-ketone, 2-hydroxy-2-methyl-1- Phenyl-propan-1-one, 1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propan-1-one, 2-hydroxy-1- {4- [4 -(2-hydroxy-2-methyl-propionyl) -benzyl] phenyl} -2-methylpropan-1-one, 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropan-1-one, 2-Benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1,2- (dimethylamino) -2-[(4-methylphenyl Methyl] -1- [4- (4-morpholinyl) phenyl] -1-butanone and the like.

  Examples of the acylphosphine oxide-based ultraviolet polymerization initiator include 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, and the like. .

  Examples of titanocene-based ultraviolet polymerization initiators include bis (η5-2,4-cyclopentadien-1-yl) -bis (2,6-difluoro-3- (1H-pyrrol-1-yl) -phenyl). Examples include titanium.

  The content of the UV polymerization initiator in the UV curable adhesive composition is such that the UV curable adhesive composition after UV curing exhibits excellent tackiness and the UV curable adhesive composition after UV curing Since it is excellent in transparency, 5 mass parts or less are preferable with respect to 100 mass parts of monofunctional acrylate compounds, and 1-3 mass parts is more preferable.

  The ultraviolet curable adhesive composition may contain additives such as a polyfunctional acrylate compound, a liquid tackifier, a plasticizer, and an ultraviolet absorber as long as the physical properties are not impaired.

  The production method of the ultraviolet curable adhesive composition is not particularly limited. For example, a general-purpose kneading apparatus containing a monofunctional acrylate compound, a rosin acrylate compound, a tackifier, and other components contained as necessary. And a method of producing an ultraviolet curable adhesive composition by stirring and kneading while heating.

  After the ultraviolet curable adhesive composition is applied to an adherend, it is irradiated with ultraviolet rays, the monofunctional acrylate compound is polymerized and cured, and exhibits excellent tackiness. The ultraviolet curable adhesive composition after ultraviolet curing has excellent transparency.

  Since the ultraviolet curable adhesive composition of the present invention has the above-described configuration, it has little odor and is excellent in handleability. Further, the ultraviolet curable adhesive composition of the present invention exhibits excellent tackiness by ultraviolet curing and maintains excellent transparency even after ultraviolet curing.

  Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited thereto.

  Details of each component used in Examples and Comparative Examples are described below.

(Monofunctional acrylate compound)
Monofunctional acrylate compound (1) [3-phenoxy-2-hydroxypropyl acrylate, viscosity at 25 ° C .: 200 mPa · s, product name “KAYARAD R-128H” manufactured by Nippon Kayaku Co., Ltd.]
Monofunctional acrylate compound (2) [2-acryloyloxyethyl phthalate, viscosity at 25 ° C .: 3000 mPa · s, product name “Aronix M-5400” manufactured by Toagosei Co., Ltd.]
Monofunctional acrylate compound (3) [Neopentyl glycol benzoate acrylate, viscosity at 25 ° C .: 70 mPa · s, trade name “Light acrylate BA-104” manufactured by Kyoeisha]
Monofunctional acrylate compound (4) [phenoxyethyl acrylate, viscosity at 25 ° C .: 15 mPa · s, trade name “AMP-10G” manufactured by Shin-Nakamura Chemical Co., Ltd.]
Monofunctional acrylate compound (5) [Caprolactone acrylate, viscosity at 25 ° C .: 80 mPa · s, Arkema Co., Ltd., trade name “SR495”]

(Rosin acrylate compound)
Rosin acrylate compound [Viscosity at 40 ° C. having the structural formula shown in Formula (1): 100,000 mPa · s, trade name “Beam Set 101” manufactured by Arakawa Chemical Industries Ltd.]

(Tackifier)
Tackifier (1) [hydrogenated rosin ester, softening point: 100 ° C., trade name “Pine Crystal KE-100” manufactured by Arakawa Chemical Co., Ltd.]
-Tackifier (2) [hydrogenated rosin ester, softening point: 85 ° C., trade name “Foral 85-E” manufactured by Eastman Co.]
-Tackifier (3) [Rosin ester, softening point: 25 ° C. or less, “RE-10L” manufactured by Arizona Chemical Co.]

(UV polymerization initiator)
UV polymerization initiator [1-hydroxy-cyclohexyl-phenyl-ketone, trade name “IRGACURE 184” manufactured by BASF Corporation]

(Examples 1-7, Comparative Examples 1-6)
The predetermined amounts of monofunctional acrylate compounds (1) to (5), rosin acrylate compounds and tackifiers (1) to (3) shown in Table 1 were added to a stirrer equipped with a heating device, and then 1 at 80 ° C. Stir with heating over time. Next, after cooling to 25 ° C., a predetermined amount of the ultraviolet polymerization initiator shown in Table 1 was added to the stirrer and stirred to obtain an ultraviolet curable adhesive composition.

  About the obtained ultraviolet curable adhesive composition, transparency, adhesiveness, odor, and irritation were measured in the following manner, and the results are shown in Table 1.

(transparency)
An ultraviolet curable adhesive composition was applied to a polyethylene terephthalate film (thickness 50 μm) at a coating amount of 20 g / m ² , and a corona-treated OPP film (thickness 25 μm) was applied to the ultraviolet curable adhesive composition with a laminator. Pasted together. Next, using an ultraviolet irradiation device (trade name “Light Hammer 6 D bulb” manufactured by Heraeus Co., Ltd.), the ultraviolet curable adhesive composition was irradiated with ultraviolet rays for 5 seconds under the conditions of an output of 50% and a height of 600 mm. Irradiation was performed to cure the ultraviolet curable adhesive composition to prepare a test piece. The transparency of the ultraviolet curable adhesive composition after ultraviolet curing in the obtained test piece was visually observed and evaluated based on the following criteria.
○: Transparent △: Translucent ×: White turbidity

(Adhesiveness)
A test piece was prepared in the same manner as in the case of transparency. Next, T-peeling of the corona-treated OPP film from the UV curable adhesive composition was performed at 25 ° C. at a speed of 300 mm / min, and the peel strength was measured. The results are shown in Table 1. It was.

(Odor and irritation)
The ultraviolet curable adhesive composition was allowed to stand at 40 ° C. for 2 hours, and the presence or absence of odor and eye irritation was observed and evaluated based on the following criteria.
○: Odor and no eye irritation △: Odor is present but no eye irritation ×: Odor and eye irritation

Claims (2)

10 to 90 parts by mass of a tackifier having a viscosity at 25 ° C. of 50 mPa · s or more and 100 parts by mass of a monofunctional acrylate compound containing an aromatic ring, 5 parts by mass or more of a rosin acrylate compound, and a softening point of 75 ° C. An ultraviolet curable adhesive composition comprising an ultraviolet polymerization initiator. The ultraviolet-curable adhesive composition according to claim 1, wherein the monofunctional acrylate compound has a viscosity at 25 ° C of 100 mPa · s or more and has a hydroxyl group or a carboxy group.