KR20190011220A - Ultraviolet ray-curable adhesive agent, cured product and adhesive sheet - Google Patents

Abstract

The purpose of the present invention is to provide a UV-curable adhesive, which is a substantially solventless UV-curable adhesive, has excellent flexibility at low and room temperature in spite of a single adhesive layer, and forms an adhesive layer having good adhesion to a low-polar substrate such as COP or the like. The UV-curable adhesive comprises in predetermined amounts: a polyurethane (meth)acrylate (A) which is a reactant resulted from reaction among polyetherpolyol (a1), polyisocyanate (a2), and mono (meth)acrylate (a3) containing a hydroxy group or mono (meth)acrylate (a3) containing an isocyanate group; a polymeric monomer (B) which has no hydroxy group and has a glass transition temperature of -70°C or more and less than 0°C when being a homopolymer; a mono(meth)acrylate (C) which contains a hydroxy group; a photopolymerization initiator (D); and an adhesive resin (E) which is at least one selected among a petroleum resin containing a hydroxy group, a disproportionated rosin resin and a hydrogenated rosin resin, and has a softening point of 100°C to 150°C.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an ultraviolet curable adhesive, a cured product,

The present invention relates to an ultraviolet curable pressure sensitive adhesive (ultraviolet curable pressure sensitive adhesive), a cured product (cured product), and a pressure sensitive adhesive sheet (pressure sensitive adhesive sheet).

2. Description of the Related Art Digital information devices such as mobile phones, portable game machines, and car navigation systems are provided with display devices such as touch panels. Optical devices such as liquid crystal devices, light emitting diode devices, and organic electroluminescence devices are widely used for such display devices .

2. Description of the Related Art In recent years, a touch panel has emphasized designability, and a demand from a conventional flat shape to a curved shape has been increasing. Further, a film-shaped touch panel is also being studied. For example, the flexible organic EL display can be folded or wound in a roll shape.

In the pressure-sensitive adhesive sheet for use in the touch panel having these shapes, the pressure-sensitive adhesive layer is required to have high flexibility, and in particular, a property that flexibility is not deteriorated from low temperature to room temperature (small change in storage elastic modulus) is required. If the flexibility of the pressure-sensitive adhesive layer is insufficient, the base material to be bonded is peeled off, which may lower the visibility and durability.

As a pressure-sensitive adhesive focusing on the storage elastic modulus, for example, a thermosetting pressure-sensitive adhesive composition containing a (meth) acrylic copolymer, a polyisocyanate crosslinking agent and an organic solvent has already been known (see Patent Document 1). However, the pressure-sensitive adhesive composition of the present invention has a storage elastic modulus G 'of less than 1 x 10 < ⁶ > Pa at a low temperature (-20 deg. In addition, since a large amount of solvent is contained, a step of removing the solvent is required when preparing the pressure-sensitive adhesive sheet.

The display of the touch panel is mainly composed of a surface glass plate, a touch panel and a liquid crystal module, and triacetyl cellulose (hereinafter referred to as TAC) is used as a film for protecting a polarizer inside the liquid crystal module. (Hereinafter referred to as " COP ") from TAC has been proceeding in order to reduce the amount of the cycloolefin polymer.

However, COP has a property that adhesive strength to adhesive layer is lower than that of TAC. In addition, adhesion to a transparent conductive film (for example, an ITO film) of a touch panel is naturally required.

(Meth) acrylic acid alkyl ester having a branched (branched) alkyl group having 4 to 9 carbon atoms in addition to 2-ethylhexyl acrylate and 4 to 9 carbon atoms, And a polymer obtained by copolymerizing a monomer having an aliphatic cyclic substituent group having 1 to 10 carbon atoms (see Patent Document 2). However, as in Patent Document 1, since a large amount of solvent is required, a step of removing a solvent is required, and a monomer having an aliphatic cyclic substituent having 4 to 10 carbon atoms has a high glass transition temperature, As a result, the low temperature flexibility was insufficient.

Japanese Unexamined Patent Application Publication No. 2015-174907 Japanese Unexamined Patent Application Publication No. 2015-183179

 The present invention relates to an ultraviolet curing pressure-sensitive adhesive which is substantially solvent-free and which has excellent flexibility at low temperature and room temperature even in the case of a single pressure-sensitive adhesive layer, and which is capable of forming an adhesive layer having good adhesiveness to a low- The main problem is to provide.

As a result of intensive studies, the present inventors have found out what can solve the above problems by incorporating a specific tackifying resin into an ultraviolet curable pressure sensitive adhesive, and have accomplished the present invention. That is, the present invention relates to the following ultraviolet curable pressure-sensitive adhesives, cured products and pressure-sensitive adhesive sheets.

1. A method for producing a polyurethane resin composition comprising reacting a polyether polyol (a1), a polyisocyanate (a2) and a hydroxyl group-containing mono (meth) acrylate (a3-1), or a reaction product of a polyether polyol (a1), a polyisocyanate (a2) and an isocyanate group- (Meth) acrylate (a3-2), a polyurethane (meth) acrylate

A polymerizable monomer (B) having a glass transition temperature of -70 ° C or more and less than 0 ° C, which is a homopolymer and has no hydroxyl group,

(C) containing a hydroxyl group-containing mono (meth) acrylate,

A photopolymerization initiator (D)

(E) having a softening point of 100 占 폚 to 150 占 폚 and at least one member selected from a hydroxyl group-containing petroleum resin, a disproportionated rosin resin and a hydrogenated rosin resin,

(A), 15 to 70% by mass of the component (B) and 50 to 70% by mass of the component (C) when the total amount of the component (A), the component ) Component is 20 to 70% by mass,

(D) is 0.1 to 5% by mass based on 100% by mass of the total of the components (A), (B) and (C)

(E) is contained in an amount of 1 to 30 mass% with respect to 100 mass% of the total of the components (A), (B) and (C)

UV curable adhesive.

2. The ultraviolet curable pressure-sensitive adhesive of item 1 or 2, wherein the component (a1) has a number average molecular weight of 700 to 10,000.

3. The ultraviolet curing pressure-sensitive adhesive according to item 1 or 2, wherein the component (a2) is an aliphatic diisocyanate and / or an alicyclic diisocyanate.

4. The ultraviolet curable pressure-sensitive adhesive of item 1 or 2, wherein the total carbon number of the component (a3-1) is 5 to 10.

5. The ultraviolet curable pressure-sensitive adhesive composition according to item 1 or 2, wherein the component (a3-2) comprises 2-isocyanatoethyl (meth) acrylate and / or 1,1- (bisacryloyloxymethyl) ethyl isocyanate .

6. The ultraviolet curable pressure-sensitive adhesive of item 1 or 2, wherein the average number of (meth) acryloyl groups of the component (A) is 1.5 to 4.

7. The ultraviolet curable pressure-sensitive adhesive according to item 1 or 2, wherein the component (A) has a weight average molecular weight of 10,000 to 90,000.

8. The ultraviolet curing pressure-sensitive adhesive of item 1 or 2 above, wherein the component (B) comprises an alkylmono (meth) acrylate having an alkyl group having 4 to 18 carbon atoms.

9. A cured product comprising the ultraviolet curable pressure-sensitive adhesive of item 1 or 2 above.

10. The cured product of Item 9, wherein a storage elastic modulus G 'at a temperature of -20 ° C and 1 Hz is 1 × 10 ⁶ Pa or less, and a storage elastic modulus G' at 25 ° C and 1 Hz is 1 × 10 ⁵ Pa or less.

11. A pressure-sensitive adhesive sheet comprising the cured product of the above item 9 on at least one surface of a substrate.

 Since the ultraviolet curing pressure-sensitive adhesive of the present invention is substantially solvent-free, the step of removing the solvent during the production of the pressure-sensitive adhesive sheet can be omitted. The cured product of the pressure-sensitive adhesive is excellent in both the storage modulus at low temperature (hereinafter also referred to as low-temperature flexibility) and the storage modulus at room temperature (hereinafter also referred to as room temperature flexibility) And has good adhesion to the substrate. Further, the cured product is transparent, has excellent step traceability and durability under high temperature and high heat and humidity. Further, even if the surface of the substrate having a low polarity is not subjected to reverse-bonding treatment, the same effect can be obtained by applying the ultraviolet curable pressure-sensitive adhesive of the present invention.

The ultraviolet curable pressure sensitive adhesive of the present invention is suitable for optical use. For example, the present invention can be applied to a display panel having a multi-layer structure in a digital display device. In addition, since it has good flexibility from a low temperature to a room temperature and has good adhesion to a substrate having low polarity such as COP, for example, when applied to a double-sided pressure-sensitive adhesive sheet for a touch panel, In addition, even if the transparent substrate on which the transparent electrode is formed in the capacitive touch panel and the polarizing plate are polar substrates, they have good adhesion and durability. Further, when applied to a flexible organic EL display, it is possible to fold or roll the flexible organic EL display.

The ultraviolet curable pressure sensitive adhesive (hereinafter, referred to as pressure sensitive adhesive) of the present invention comprises a predetermined polyurethane (meth) acrylate (A) (hereinafter referred to as component (A)) and a glass transition temperature of- (B) (hereinafter, referred to as component (B)), a hydroxyl group-containing mono (meth) acrylate (hereinafter referred to as component (C) and a photopolymerization initiator (D) (E) having a softening point of 100 占 폚 to 150 占 폚 (hereinafter, referred to as "component (D)"), at least one member selected from the group consisting of a hydroxyl group-containing petroleum resin, a disproportionated rosin resin and a hydrogenated rosin resin E) component).

The component (A) is a polyurethane having a (meth) acryloyl group in the molecule. The polyether polyol (a1) (Meth) acrylate (a3-1) (hereinafter referred to as component (a3-1)) or a reaction product of the component (a1), the component (a2) and the isocyanate group-containing mono (meth) (Hereinafter referred to as component (a3-2)).

The component (a1) is not particularly limited and various known compounds can be used. For example, polyethylene glycol, polypropylene glycol, and polytetramethylene glycol, and they may be used in combination of two or more. As commercial products, for example, adeka polyether polyol 1000, adeka polyether polyol 2000 (manufactured by ADEKA), PTMG 650, PTMG 1000 and PTMG 2000 (manufactured by Mitsubishi Chemical Corporation) . Of these, polypropylene glycol is preferable from the viewpoint of low-temperature flexibility.

The physical properties of the component (a1) are not particularly limited, but the number average molecular weight (in terms of polystyrene conversion by gel permeation chromatography, hereinafter the same) is usually about 700 to 10,000 in terms of durability, Is about 1,000 to 4,000. The average number of hydroxyl groups in one molecule (average number of hydroxyl groups) is not particularly limited, but is usually about 1.5 to 3, preferably about 2 to 3, in view of the flexibility of the pressure-sensitive adhesive layer. The average number of hydroxyl groups per molecule means the average number of hydroxyl groups present in one molecule of the component (a1).

The component (a2) is not particularly limited and various known compounds can be used. Aromatic diisocyanates such as tolylene diisocyanate, diphenylmethane diisocyanate and xylylene diisocyanate; Aliphatic diisocyanates such as hexamethylene diisocyanate, trimethylhexamethylene diisocyanate and lysine diisocyanate; Alicyclic diisocyanates such as dicyclohexylmethane diisocyanate, isophorone diisocyanate, 1,4-cyclohexane diisocyanate, hydrogenated xylylene diisocyanate, and hydrogenated tolylene diisocyanate, and the like, or two or more of them may be used in combination . Of these, aliphatic diisocyanates and / or alicyclic diisocyanates are particularly preferable in view of transparency and low-temperature flexibility.

The component (a3-1) is not particularly limited and various known ones can be used. (Meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl acrylate, 3-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (Meth) acrylate, and 6-hydroxyhexyl acrylate. These mono (meth) acrylates may be used in combination of two or more. Of these, mono (meth) acrylates having a total of 5 to 10 carbon atoms are preferred from the viewpoint of durability and low-temperature flexibility, and 2-hydroxyethyl (meth) acrylate, 4-hydroxybutyl (meth) Acrylate is more preferable.

The component (a3-2) is not particularly limited and various known ones can be used. For example, 2-isocyanatoethyl (meth) acrylate and 1,1- (bisacryloyloxymethyl) ethyl isocyanate, methacrylic acid 2- (o- [1'methylpropylideneamino] carboxyamino) ethyl And 2-isocyanatoethyl (meth) acrylate and 1,1- (bisacryloyloxymethyl) ethyl isocyanate are preferable from the viewpoint of durability.

The component (A) is not particularly limited and is produced by various known methods. (A2) obtained by using the component (A1) (hereinafter referred to as component (A1)) obtained by using the component (a3-1) as the component (a3) and the component (a3-2) (Hereinafter referred to as component (A2)).

The component (A1) is not particularly limited, but for example, an isocyanate group-terminated urethane prepolymer (hereinafter referred to as component (A1 ')) is prepared by reacting the component (a1) And the component (a3-1). The reaction conditions are not particularly limited, and usually the temperature is about 70 to 85 캜 and the time is about 1 to 5 hours. In addition, (a1) component and (a2), but the proportion of the component is not particularly limited, (a2) mol number can mol of hydroxyl group of (NCO _(a2)) and (a1) component (OH _(a1 of the isocyanate groups of component ₎ (NCO _(a2) / OH _(a1) ) is usually in the range of about 1.01 to 2. The ratio of the number of moles of the isocyanate group of the former (NCO _{(A1 ')} ) to the number of moles of the latter hydroxyl group (OH _(a3-1)) is not particularly limited _, ) (NCO _{(Al ')} / OH _(a3-1) ) is usually in the range of about 0.25 to 1.

(A2 ') is obtained by reacting the component (a1) and the component (a2) to obtain a hydroxyl-terminated urethane prepolymer (hereinafter referred to as component (A2' good. The reaction temperature and the reaction time are the same as above. The ratio of the component (a1) to the component (a2) is not particularly limited, but may be in the range of (NCO _(a2) / OH _(a1) ) usually in the range of about 0.50 to 0.99. The ratio of the number of moles of the isocyanate group (NCO _(a3-2) ) to the number of moles of the hydroxyl group (OH _{(A2 ')) of the} former is not particularly limited _, ) (NCO _(a3-2) / OH _{(A2 ')} ) is usually in the range of 0.5 to 1.

These components (A1) and (A2) may be produced in the absence of a solvent or in the presence of a component (B) described later.

As the component (A), the components (A1) and (A2) may be used in combination.

The average number of (meth) acryloyl groups of the component (A) is usually about 1.5 to 4, preferably about 1.8 to 2.2 in terms of durability and flexibility. The average number of (meth) acryloyl groups in the component (A) means the average number of (meth) acryloyl groups present in one molecule of the component (A).

The physical properties of the component (A) are not particularly limited, but the weight average molecular weight is preferably from 10,000 to 90,000, more preferably from 20,000 to 70,000 from the viewpoint of adhesion and durability. The Gardner color scale is not particularly limited, but is preferably 1 or less.

The content of the component (A) is 10 to 60% by mass when the total amount of the component (A), the component (B) and the component (C) is 100 mass%. When the amount is less than 10% by mass, the curability and the adhesive strength are liable to deteriorate. When the amount is more than 60% by mass, the handling property of the pressure-sensitive adhesive of the present invention tends to deteriorate. From the same viewpoint, it is preferably 20 to 60 mass%, more preferably 20 to 45 mass%.

The component (B) is a polymerizable monomer having a glass transition temperature of -70 ° C or higher and less than 0 ° C when it is a homopolymer and does not have a hydroxyl group, and various known ones can be used without particular limitation. When the glass transition temperature is used, the low temperature flexibility and room temperature flexibility are likely to be improved. (Meth) acrylate, n-octyl (meth) acrylate, nonyl (meth) acrylate, isononyl (meth) acrylate, (Meth) acrylate, isodecyl (meth) acrylate, lauryl (meth) acrylate, cetyl (meth) acrylate and isostearyl (meth) acrylate. . Of these, alkylmono (meth) acrylates having 4 to 18 carbon atoms in the alkyl group are preferable from the viewpoints of low temperature flexibility and room temperature flexibility, and it is more preferable that the alkyl group is branched (branched).

Quot; glass transition temperature when homopolymer " in the component (B) is a value described in "Polymer Handbook" of Wiley-Interscience (hereinafter referred to as "glass transition temperature" ). For example, the Tg of 2-ethylhexyl acrylate is -70 ° C, and the Tg of n-butyl acrylate is -54 ° C.

The content of the component (B) is from 15 to 70 mass% when the total amount of the component (A), the component (B) and the component (C) is 100 mass%. If it is less than 15% by mass, the low temperature flexibility of the cured product of the present invention tends to be impaired. If it exceeds 70% by mass, the adhesive force tends to deteriorate. From the same viewpoint, it is preferably 20 to 60 mass%, more preferably 20 to 50 mass%.

The component (C) is not particularly limited and various known ones can be used. For example, 2-hydroxyethyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, cyclohexanedimethanol mono (meth) acrylate, and the like. Of these, 4-hydroxybutyl (meth) acrylate is preferable from the viewpoints of low temperature flexibility and room temperature flexibility.

The content of the component (C) is 20 to 70 mass% when the total of the component (A), the component (B) and the component (C) is 100 mass%. When the amount is less than 20% by mass, the curing property and durability of the pressure-sensitive adhesive of the present invention are likely to deteriorate, and durability tends to deteriorate even if the content exceeds 70% by mass. From the same viewpoint, it is preferably 20 to 60 mass%, more preferably 20 to 50 mass%.

The component (D) is not particularly limited and various known ones can be used. For example, a photopolymerization initiator such as a benzoin compound, an acetophenone compound, an acylphosphine oxide compound, a titanocene compound, a thioxanthone compound, or an oxime ester compound; And photosensitizers such as amine and quinone. Specific examples thereof include 2,2-dimethoxy-1,2-diphenylethane-1-one, 1-hydroxycyclohexyl phenyl ketone, 2- Methyl-1-phenylpropan-1-one, 1- [4- (2-hydroxyethoxy) phenyl] -2-hydroxy- Methyl-1- (4-methylthiophenyl) -2-methylpropan-1- 2-morpholinopropane-1-one, 2- (dimethylamino) -2 - [(4-methylphenyl) methyl] , 4, 6-trimethylbenzoyl diphenylphosphine oxide, bis (2,4,6-trimethylbenzoyl) phenyl phosphine oxide, bis (η ⁵ -2,4- cyclopentadiene-1-yl) bis (2, (Phenylthio) -2- (o-benzoyloxime)], ethanone 1 (1-methyl- - [9-ethyl-6- (2-methylbenzoyl) -9H-carbazol-3-yl] -1- (o-acetyloxime) The. Of these, 2,4,6-trimethylbenzoyldiphenylphosphine oxide is preferable from the viewpoint of adhesion to COP or other low polarity base materials.

The content of the component (D) is 0.1 to 5 mass% with respect to 100 mass% of the total of the component (A), the component (B) and the component (C). If it is less than 0.1% by mass, the curing property of the pressure-sensitive adhesive of the present invention tends to deteriorate. If it exceeds 5% by mass, the durability tends to deteriorate. From the same viewpoint, it is preferably 0.5 to 2% by mass.

(E) is at least one member selected from the group consisting of a hydroxyl group-containing petroleum resin, a disproportionated rosin resin and a hydrogenated rosin resin. Among them, at least one species selected from the group consisting of a hydroxyl group-containing hydrogenated petroleum resin, a disproportionated rosin resin and a hydrogenated rosin resin is preferable from the viewpoint of excellent adhesion and durability to substrates with low polarity such as COP.

The hydroxyl group-containing petroleum resin is not particularly limited and various known ones can be used. For example, an aliphatic petroleum resin, an aromatic petroleum resin and a dicyclopentadiene petroleum resin depending on the type of raw material monomer (fraction).

The aliphatic petroleum resin is not particularly limited, and examples thereof include a C5 petroleum resin and a C5-C9 petroleum resin. The aromatic petroleum resin is not particularly limited, and for example, a C9 petroleum resin can be cited.

The C5-based petroleum resin is obtained by cationic polymerization of C5-based petroleum oil (for example, pentene, methylbutene, isoprene, cyclopentene, etc.). The C9-based petroleum resin is not particularly limited, but a material obtained by cationic polymerization of a C9-based petroleum oil fraction (for example, styrene, vinyltoluene,? -Methylstyrene, indene, etc.) obtained by cracking of naphtha . The C5-C9 petroleum resin is obtained by copolymerizing the C5 petroleum oil fraction and the C9 petroleum oil fraction in the same manner as the C5 petroleum resin. The dicyclopentadiene-based petroleum resin is a thermally or cationically polymerized dicyclopentadiene.

The hydroxyl group-containing hydrogenated petroleum resin is obtained by hydrogenating the hydroxyl group-containing petroleum resin. The reaction conditions include, but are not limited to, hydrogen in the presence of a hydrogenation catalyst at a pressure of about 2 to 20 MPa (preferably about 5 to 20 MPa) and heating at about 100 to 300 캜 (about 150 to 300 캜) And the like.

The hydrogenation catalyst is not particularly limited, and examples thereof include supported catalyst, metal powder, iodine, iodide and the like. The supported catalyst is not particularly limited, and examples thereof include palladium-carbon, rhodium-carbon, ruthenium-carbon and platinum-carbon. The metal powder is not particularly limited, and examples thereof include nickel and platinum. The iodide is not particularly limited, and examples thereof include iron iodide and the like. Of these catalysts, palladium, rhodium, ruthenium and platinum catalysts are preferable in that hydrogenation can be shortened while increasing the hydrogenation rate. The amount of the hydrogenation catalyst to be used is not particularly limited, but is usually about 0.01 to 5 parts by mass, preferably about 0.01 to 2 parts by mass, per 100 parts by mass of the hydroxyl group-containing petroleum resin.

Next, the disproportionated rosin resin and the hydrogenated rosin resin will be described, respectively. First, the raw material rosin to be used is described.

<Raw material rosin>

The raw material rosin is not particularly limited, and natural rosins such as gum rosin, tall oil rosin and wood rosin; Natural rosin refined tablets; Maleated rosin, fumarated rosin, acrylated rosin, polymerized rosin, polymerized rosin ester, rosin-modified phenol, rosin ester, and the like.

The preparation method of the tablets is not particularly limited, and known ones such as a vacuum distillation method, a steam distillation method, an extraction method, and a recrystallization method can be appropriately selected.

The polymerized rosin is not particularly limited and can be obtained, for example, by heating natural rosin in the presence of a polymerization catalyst. The polymerization catalyst is not particularly limited, and examples thereof include acids such as sulfuric acid, phosphoric acid and hydrofluoric acid; And metal halides such as boron fluoride, aluminum chloride and zinc chloride.

The rosin ester is not particularly limited and is obtained, for example, by reacting a natural rosin with an alcohol under heating. If necessary, an esterification catalyst may be added to the reaction.

The alcohol is not particularly limited, and examples thereof include aliphatic monovalent or polyvalent alcohols having 1 to 20 carbon atoms. Examples of such alcohols include methanol, ethanol, isopropyl alcohol, isoamyl alcohol, n-hexyl alcohol, Monohydric alcohols such as 2-ethylhexyl alcohol, n-octyl alcohol, dodecyl alcohol, lauryl alcohol, stearyl alcohol and dihydroabiethyl alcohol; Dihydric alcohols such as ethylene glycol, diethylene glycol, propylene glycol and neopentyl glycol; Trihydric alcohols such as glycerin, trimethylolethane and trimethylolpropane; And tetravalent alcohols such as pentaerythritol and diglycerin.

The esterification catalyst is not particularly limited, and examples thereof include acid catalysts such as acetic acid and para-toluenesulfonic acid; Hydroxides of alkali metals such as lithium hydroxide, sodium hydroxide and potassium hydroxide; Hydroxides of alkaline earth metals such as calcium hydroxide and magnesium hydroxide; And metal oxides such as calcium oxide, magnesium oxide, zinc oxide, lead oxide and tin oxide.

Hydrogenated rosin may be used for the raw rosin of the disproportionated rosin resin, and disproportionated rosin may be used for the raw rosin of the hydrogenated rosin resin.

<Disproportionated rosin resin>

The disproportionated rosin resin is not particularly limited and can be obtained by various known methods. For example, the disproportionated rosin resin is obtained by heat-reacting the above-mentioned raw material rosin in the presence of a disproportionation catalyst.

The disproportionation catalyst is not particularly limited, and examples thereof include supported catalysts such as palladium-carbon, rhodium-carbon, and platinum-carbon; Metal powders such as nickel and platinum; Iodine such as iodine and iron iodide, and the like can be used. The amount of the catalyst to be used is usually about 0.01 to 5 parts by mass, and preferably about 0.01 to 1 part by mass based on 100 parts by mass of the raw material rosin. The reaction temperature is about 100 to 300 占 폚, preferably about 150 to 290 占 폚.

<Hydrogenated rosin resin>

The hydrogenated rosin resin is not particularly limited and can be obtained by various known methods. For example, the rosin may be hydrogenated at a pressure of about 2 to 20 MPa (preferably about 5 to 20 MPa) in the presence of a hydrogenation catalyst, And heating the mixture at about 100 to about 300 DEG C (preferably about 150 to about 300 DEG C).

The hydrogenation catalyst is not particularly limited, and examples thereof include supported catalyst, metal powder, iodine, iodide and the like. The supported catalyst is not particularly limited, and examples thereof include palladium-carbon, rhodium-carbon, ruthenium-carbon and platinum-carbon. The metal powder is not particularly limited, and examples thereof include nickel and platinum. The iodide is not particularly limited, and examples thereof include iron iodide and the like. Of these catalysts, palladium, rhodium, ruthenium and platinum catalysts are preferable in that hydrogenation can be shortened while increasing the hydrogenation rate. The amount of the hydrogenation catalyst to be used is not particularly limited, but is usually about 0.01 to 5 parts by mass, and preferably about 0.01 to 2 parts by mass based on 100 parts by mass of the raw material rosin.

The component (E) of the present invention has a softening point of 100 to 150 캜. If it is less than 100 ° C, the adhesive force to a low polarity substrate such as COP tends to deteriorate easily, and if it exceeds 150 ° C, low temperature flexibility tends to deteriorate. From the same viewpoint, it is preferably 100 to 140 占 폚.

The content of the component (E) is 1 to 30 mass% with respect to 100 mass% of the total of the components (A), (B) and (C). If it is less than 1% by mass, the adhesive force to a substrate having low polarity such as COP tends to be deteriorated. If it exceeds 30% by mass, the curing property and durability of the pressure sensitive adhesive of the present invention tends to deteriorate. From the same viewpoint, it is preferably 5 to 25 mass%.

The pressure-sensitive adhesive of the present invention may contain various known additives as necessary. For example, a surface modifier, a surfactant, an ultraviolet absorber, an antioxidant, a light stabilizer, an inorganic filler, a silane coupling agent, a colloidal silica, a defoaming agent, a wetting agent and an antirust agent may be used.

The pressure-sensitive adhesive of the present invention is obtained by mixing components (A), (B), (C), (D) and (E) The mixing means and the mixing order are not particularly limited. When the component (A) is diluted with the component (B), the component (C), the component (D) and the component (E) are added to the solution of the component (B) in the component .

The pressure-sensitive adhesive of the present invention is substantially solvent-free, but the component (B) or the component (C) may be used as a solvent.

The physical properties of the pressure-sensitive adhesive of the present invention are not particularly limited. For example, the viscosity (mPa · s / 25 ° C) is usually about 100 to 15000 mPa · s. The viscosity was measured by an E-type viscometer (TVE-10 manufactured by Toki Sangyo Co., Ltd.) (5 minutes).

The cured product of the present invention is obtained by curing the ultraviolet curing type pressure-sensitive adhesive of the present invention.

The cured product of the present invention is not particularly limited and can be obtained by applying the pressure-sensitive adhesive of the present invention to a substrate and irradiating it with ultraviolet rays.

Examples of the substrate include, but are not limited to, polyethylene terephthalate film (PET film), cycloolefin polymer (COP film), polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, Vinyl acetate copolymer film, polyethylene naphthalate film, polybutylene terephthalate film, polyurethane film, ethylene vinyl acetate film, ionomer resin film, ethylene (meth) acrylic acid copolymer film, ethylene (meth) A co-extruded film, a polystyrene film, a polycarbonate film, a polyimide film, a fluororesin film and the like. These crosslinked films or laminated films may also be used. These films may be subjected to a light to heavy stripping treatment or may be provided with an adverse adhesive layer.

The application method is not particularly limited, and examples thereof include an applicator, a bar coater, a roll coater, a knife coater, and a gravure coater.

The ultraviolet light source is not particularly limited, and examples thereof include a xenon lamp, a high-pressure mercury lamp, and a metal halide lamp. In addition, the amount of light and the conveying speed of ultraviolet rays are not particularly limited, but usually the light quantity is about 80 to 160 W / cm and the conveying speed is usually about 5 to 50 m / min.

The thickness of the cured product of the present invention is not particularly limited, and is usually about 10 to 1000 m, preferably about 25 to 500 m.

The cured product of the present invention has a storage elastic modulus G 'at a temperature of -20 ° C and 1 Hz (hereinafter referred to as a low temperature G') of usually 1 × 10 ⁶ Pa or less and a storage elastic modulus G ' , Room temperature G ') is 1 x 10 &lt; ⁵ &gt; Pa or less. It is considered that the cured product is excellent in low-temperature flexibility and room temperature flexibility because of having such characteristics, and also has excellent adhesion to substrates having low polarity such as COP.

The pressure-sensitive adhesive sheet of the present invention comprises a cured product of the present invention on at least one side of a substrate. The adhesive sheet may be processed into a tape shape. Examples of the substrate include those described above.

[Example]

Hereinafter, the present invention will be described in detail with reference to examples and comparative examples. It goes without saying that the technical scope of the present invention is not limited by them. In the examples, &quot; part &quot; and &quot;% &quot; are on a mass basis unless otherwise specified.

In each production example, the weight average molecular weight of the component (A) is a polystyrene conversion value by gel permeation chromatography, and the measurement conditions are as follows.

Measuring device body: product name "HLC-8220GPC", Tosoh Corporation product

Column: Product names "TSKGel G1000H" and "TSKGel G2000H", all products of Doso Co., Ltd.

Developing solvent: tetrahydrofuran

Production Example 1-1

884 parts of polypropylene glycol having a number average molecular weight of 2000 (trade name: ADEKA POLYERTER P-2000, available from ADEKA Co., Ltd.) (hereinafter referred to as PPG2000) (Hereinafter referred to as &quot; IPDI &quot;), 333 parts of 2-ethylhexyl acrylate (hereinafter referred to as 2-EHA) and 0.4 part of tin octylate were added, and the mixture was heated to 80 DEG C and kept at this temperature for 3 hours. To obtain a 2-EHA solution which is a urethane prepolymer. Subsequently, 10 parts of 4-hydroxybutyl acrylate (hereinafter referred to as 4HBA) was added and the mixture was kept at 80 DEG C for 2 hours. By confirming the completion of the reaction by NCO measurement, the weight average molecular weight was 55,000 and the average of (meth) acryloyl groups To obtain a 2-EHA solution of polyurethane acrylate having a number of 2.0 (hereinafter referred to as component (A-1)).

Production Example 1-2

910 parts of PPG2000, 82 parts of hexamethylene diisocyanate (hereinafter referred to as HDI), 333 parts of 2-EHA and 0.4 part of tin octylate were added to the same reaction apparatus as in Production Example 1-1, and the mixture was heated to 80 DEG C and kept warm for 3 hours To obtain a 2-EHA solution of an isocyanate-terminated urethane prepolymer which is an intermediate. Subsequently, 8 parts of 2-hydroxyethyl acrylate (hereinafter referred to as HEA) was added and the mixture was kept at 80 DEG C for 2 hours. By confirming the completion of the reaction by NCO measurement, the weight average molecular weight was 57,000 and the average of (meth) acryloyl groups To obtain a 2-EHA solution of a polyurethane acrylate having a number of 2.0 (hereinafter referred to as (A-2) component).

Production Example 1-3

897 parts of PPG2000, 93 parts of IPDI, 250 parts of 2-EHA and 0.5 parts of tin octylate were added to the same reaction apparatus as in Production Example 1-1, and the temperature was raised to 80 캜 and maintained at that temperature for 3 hours. To obtain a 2-EHA solution which is a hydroxyl-terminated urethane oligomer as an intermediate. Subsequently, 10 parts of 2-isocyanatoethyl methacrylate was added, and the mixture was kept at 80 DEG C for 2 hours. By confirming the completion of the reaction by NCO measurement, the weight average molecular weight was 47,000 and the average number of (meth) acryloyl groups was 2.0 (Hereinafter referred to as component (A-3)) was obtained.

Production Example 2-1 (Production of hydrogenated rosin ester (E-1)

(Product of ARAKAWA CHEMICAL INDUSTRIES, LTD.) With a commercially available disproportionated rosin (acid value: 162 mgKOH / g, softening point: 79 캜) was distilled under a reduced pressure of 3 mmHg under nitrogen sealing to obtain an acid value of 175 mgKOH / g, Of the disproportionated rosin (1).

700 g of the obtained disproportionated disproportionated rosin (1) was heated to 180 캜 under an argon atmosphere, 92 g of pentaerythritol was added thereto at 220 캜 under melting and stirring, and esterification reaction was carried out at 280 캜 for 15 hours to obtain 695 g of a resin acid ester composition. The water generated by the esterification was discharged to the outside of the system through a partial condenser. Subsequently, 250 g of the ester composition, 250 g of xylene and 12.5 g of a 5% Pd-carbon catalyst (50% functional product of NE CHEMCAT Corporation) were placed in a 1 L autoclave, , The pressure was increased to 15 MPa and hydrogenation was carried out at 220 캜 for 3 hours. After cooling the reaction vessel and blowing the solution with hydrogen, the catalyst was removed by filtration to obtain a xylene solution of the ester composition. Subsequently, xylene was removed from the solution by vacuum distillation to obtain 236 g of a component (E-1) having a softening point of 117 캜.

Example 1

(Hereinafter referred to as &quot; Luna 200 &quot; (trade name) manufactured by DKSH Japan) as the component (A-1), 2-EHA as the component (B), 4HBA as the component (C), 1-hydroxycyclohexyl phenyl ketone ) And 2,4,6-trimethylbenzoyldiphenylphosphine oxide (trade name "SPEEDCURE TPO" (hereinafter referred to as TPO) manufactured by Lambson Group Ltd.) and component (E) To obtain an ultraviolet curing type pressure-sensitive adhesive.

Examples 2 to 12 and Comparative Examples 1 to 7

An ultraviolet curable pressure sensitive adhesive was obtained in the same manner as in Example 1 with the composition shown in Table 1.

* 1: The amount (mass%) of the component (D) used is the ratio of the total mass of the component (A), the component (B) and the component (C) to 100 mass%

* 2: The amount (mass%) of the component (E) used is the ratio when the total mass of the component (A), the component (B) and the component (C) is 100 mass%

The abbreviations of the components in Table 1 mean the following compounds.

&Lt; Component (A) >

A-1: Polyurethane acrylate of Production Example 1-1

A-2: Polyurethane acrylate of Production Example 1-2

A-3: Polyurethane acrylate of Production Example 1-3

&Lt; Component (B) >

2-EHA: 2-ethylhexyl acrylate

ISTA: isostearyl acrylate

&Lt; Component (C) >

4HBA: 4-hydroxybutyl acrylate

&Lt; Component (D) >

L200: 1-Hydroxycyclohexyl phenyl ketone (trade name: "Luna 200", product of DKSH Japan)

TPO: 2,4,6-trimethylbenzoyldiphenylphosphine oxide (trade name "SPEEDCURE TPO" manufactured by Lambson Group Ltd.)

&Lt; Component (E) >

E-1: Hydrogenated rosin ester of Preparation Example 2-1 (softening point: 117 占 폚)

KE-100: disproportionated rosin ester (trade name: Fine Crystal KE-100, product of Arakawa Chemical Industries, Ltd., softening point: 105 ° C)

KR-1842: hydrogenated aromatic petroleum resin containing hydroxyl group (product name: "ARKON KR-1842", product of Arakawa Chemical Industries, Ltd., softening point: 118 ° C)

KR-140: hydrogenated polymerization rosin (trade name: Fine Crystal KR-140, product of Arakawa Chemical Industries, Ltd., softening point: 140 ° C)

P-115: Hydrogenated aromatic petroleum resin (product name: "ARCON P-115" manufactured by Arakawa Chemical Industries, Ltd., softening point: 115 ° C)

M-115: Hydrogenated aromatic petroleum resin (product name: "ARCON M-115", product of Arakawa Chemical Industries, Ltd., softening point: 115 ° C)

KE-311: hydrogenated rosin ester (trade name: Fine Crystal KE-311, product of Arakawa Chemical Industries, Ltd., softening point: 90 ° C)

ME-D: Liquid disproportionated rosin ester (product name: Fine Crystal ME-D, product of Arakawa Chemical Industries, Ltd.)

The compatibility and viscosity of each of the ultraviolet curable pressure-sensitive adhesives of Examples and Comparative Examples were evaluated and measured according to the following criteria and conditions.

<Compatibility>

○: uniform and completely transparent

×: Confirmation of whitening, sediment, insoluble material and liquid phase separation

<Viscosity>

The sample was measured under the conditions of an E-type viscometer (TVE-10 (manufactured by Sekisui Chemical Co., Ltd.) at a temperature of 25 占 폚 for 5 minutes.

Evaluation Examples 1 to 12, Comparative Evaluation Examples 1 to 5

The following items were evaluated using each of the ultraviolet curable pressure-sensitive adhesives of Examples and Comparative Examples.

1. Measurement of the storage elastic modulus G 'of the pressure-sensitive adhesive sheet

(1) Each of the pressure-sensitive adhesives was laminated on a 75 μm thick heavyweight exfoliated polyester film (product of PANAC CO., LTD., Trade name "SP-PET-03-75BU" And the release treatment surface of a light-peeled polyester film (product name: "SP-PET-01-38BU", product of Panak Co., Ltd.) having a thickness of 38 μm is bonded to the coating layer. Next, ultraviolet rays were irradiated in the atmosphere with a high-pressure mercury lamp (100 mW / cm ² , 900 mJ / cm ² ) to produce a laminated film (lightly peeled polyester film / hardened product / heavy processed polyester film) did.

(2) Next, a test piece of 1 cm x 1 cm was cut out from the laminated film, and then the lightly peeled polyester film and the heavyly wrinkled polyester film were peeled to obtain a pressure-sensitive adhesive sheet.

(3) Next, the adhesive sheet was placed on a commercially available measuring instrument (Thermo Fisher Scientific K.K., product HAAKE MARS II CTC (ARES)) and the dynamic viscoelasticity was measured under the following conditions. From the measurement results, the storage elastic modulus G 'at -20 ° C and 100 ° C was obtained.

Deformation mode: twist

Measuring frequency: 1Hz

Heating rate: 3 ° C / min

Measuring temperature: -50 to 100 ° C

Shape: Parallel plate 20.0mmφ

2. Step Followability

(1) Item 1. A laminated film was prepared so that the thickness of the cured product was 50 μm as shown in (1), then the lightly peeled polyester film was peeled off, and a polyester film (trade name: (Product name: COSMOSHINE A-4300) manufactured by TOYOBO CO., LTD.) Was bonded with a 2 kg roller and allowed to stand for 2 hours. Next, a test piece of 8 cm x 8 cm was cut out from this, and the heavy-weight treated polyester film was peeled off to obtain a single-sided pressure-sensitive adhesive sheet (Cosmo Shine A-4300 / cured product).

(2) On the other hand, a glass plate of 10 cm x 10 cm x 2 mm was prepared, and a polyester film piece (5 cm x 5 cm x 20 m) was placed thereon.

(3) Subsequently, the above-mentioned single-sided pressure-sensitive adhesive sheet was placed so as to completely cover the polyester film piece, and the pressure-sensitive adhesive sheet was closely contacted with a 2 kg roller to obtain a laminate (Cosmo Shine A-4300 / (20 μm thick) / glass plate).

(4) Next, the autoclave was treated at 50 DEG C, 0.5 MPa, and 20 minutes. After standing for 24 hours under the conditions of a temperature of 25 ° C and a humidity of 50%, the sample was allowed to stand for 24 hours under the conditions of a temperature of 85 ° C and a humidity of 85% in a constant temperature and constant humidity bath.

(5) Subsequently, the step traceability of the laminate was visually evaluated based on the following criteria.

1: Polyester Film Flaking along each side of the film is not confirmed and bubbles are not observed.

2: The polyester film is not easily detected along the sides of the film, but it is possible to confirm 5 minute bubbles.

3: A slightly wider stretch is observed along each side of the polyester film piece, and even 10 minute bubbles can be confirmed by the limit

4: Wider width is observed along each side of the polyester film piece, and not only fine bubbles but also large bubbles can be identified

3. Adhesion

(1) The single-sided pressure-sensitive adhesive sheet according to item (1) above was coated on a glass plate, a 50 μm thick surface untreated polyester film (trade name: "Lumirra T60" (Cosmo Shine A-4300 / cured product / glass, PET, COP) was produced by bonding each of them with 2 kg rollers to COP (product of Zeon Corporation, product name "ZeonorFilm ZF14" And this was allowed to stand for 24 hours under conditions of a temperature of 25 캜 and a humidity of 50%.

(2) Subsequently, the single-sided pressure-sensitive adhesive sheet was peeled off from the glass plate at a rate of 300 mm / min in the direction of 180 DEG from the glass plate using a commercially available tester (A & D Company, Limited, Tensilon universal material tester) (N / 25 mm) was measured.

4. Transparency

The haze value of the laminate according to the item 3. (1) and the haze value after standing for 500 hours in a constant-temperature and constant humidity chamber at a temperature of 85 ° C and a humidity of 85% were measured with a color meter (manufactured by MURAKAMI COLOR RESEARCH LABORATORY) Using a haze meter, measurements were made in accordance with JIS K 5400. The obtained haze value is a value including the haze value of the substrate (Cosmo Shine A-4300 and glass plate).

5. Durability of Cured Products

The laminate according to the item 3. (1) was allowed to stand at a temperature of 85 ° C and a humidity of 85% for 500 hours in a constant temperature and humidity bath, and then the durability of the cured product was evaluated according to the following criteria.

?: Peeling of substrate, displacement of adhesive layer position, bubble in adhesive layer, breakage of adhesive layer none

X: At least one defect such as peeling of the substrate, deviation of the position of the adhesive layer, bubbles in the adhesive layer, and breakage of the adhesive layer occurred

adhesive
Composition The storage elastic modulus G '(Pa) Step
Follow-up Adhesive force (N / 25mm) Transparency durability -20 ° C 100 ℃ Glass PET COP Before heating
Haze value After heating
Haze value Evaluation example 1 Example 1 1.2 × 10 ⁵ 5.0 × 10 ⁴ One 32 19 10 0.3 0.3 ○ Evaluation example 2 Example 2 9.4 × 10 ⁴ 3.8 × 10 ⁴ One 27 17 9 0.3 0.3 ○ Evaluation example 3 Example 3 3.2 × 10 ⁵ 6.8 x 10 ⁴ One 20 18 10 0.3 0.3 ○ Evaluation example 4 Example 4 4.5 × 10 ⁵ 7.4 × 10 ⁴ One 29 18 10 0.3 0.3 ○ Evaluation Example 5 Example 5 6.2 × 10 ⁴ 1.8 x 10 ⁴ One 28 24 14 0.3 0.3 ○ Evaluation example 6 Example 6 4.6 × 10 ⁵ 8.2 × 10 ⁴ One 24 20 16 0.3 0.3 ○ Evaluation example 7 Example 7 1.3 x 10 ⁵ 5.4 × 10 ⁴ One 18 16 9 0.3 0.3 ○ Evaluation example 8 Example 8 9.8 × 10 ⁴ 4.0 × 10 ⁴ One 28 20 10 0.3 0.3 ○ Evaluation example 9 Example 9 6.5 x 10 ⁴ 2.2 x 10 ⁴ One 35 21 12 0.3 0.3 ○ Evaluation example 10 Example 10 4.5 x 10 ⁴ 9.4 × 10 ³ One 27 18 10 0.3 0.3 ○ Evaluation Example 11 Example 11 1.1 × 10 ⁵ 5.2 × 10 ⁴ One 21 14 9 0.3 0.3 ○ Evaluation example 12 Example 12 8.3 × 10 ⁴ 2.2 x 10 ⁴ One 18 15 9 0.3 0.3 ○ Comparative Evaluation Example 1 Comparative Example 3 6.6 x 10 ⁴ 2.5 x 10 ³ One 15 7 4 0.3 0.3 ○ Comparative Evaluation Example 2 Comparative Example 4 7.5 x 10 ⁴ 2.8 × 10 ³ One 25 15 6 0.3 0.3 ○ Comparative Evaluation Example 3 Comparative Example 5 2.0 x 10 ⁴ 2.5 x 10 ³ One 10 9 5 0.3 0.3 × Comparative Evaluation Example 4 Comparative Example 6 Not measurable due to poor curability Comparative Evaluation Example 5 Comparative Example 7 2.5 x 10 ⁴ 5.9 x 10 ³ One 26 14 8 0.3 1.3 ×

Claims (11)

A reaction product of a polyether polyol (a1), a polyisocyanate (a2) and a hydroxyl group-containing mono (meth) acrylate (a3-1) or a reaction product of a polyether polyol (a1), a polyisocyanate (a2) and an isocyanate group- (Meth) acrylate (A) which is a reactant of an acrylate (a3-2)
A polymerizable monomer (B) having a glass transition temperature of -70 ° C or more and less than 0 ° C, which is a homopolymer and has no hydroxyl group,
(C) containing a hydroxyl group-containing mono (meth) acrylate,
A photopolymerization initiator (D)
(E) having a softening point of 100 占 폚 to 150 占 폚 and at least one member selected from a hydroxyl group-containing petroleum resin, a disproportionated rosin resin and a hydrogenated rosin resin,
(A), 15 to 70% by mass of the component (B) and 50 to 70% by mass of the component (C) when the total amount of the component (A), the component ) Component is 20 to 70% by mass,
(D) is 0.1 to 5% by mass based on 100% by mass of the total of the components (A), (B) and (C)
(Ultraviolet curing type pressure-sensitive adhesive) characterized in that the content of the component (E) is 1 to 30% by mass relative to the total of 100% by mass of the component (A), the component (B) .
The method according to claim 1,
(a1) has a number average molecular weight of 700 to 10,000.
3. The method according to claim 1 or 2,
wherein the component (a2) is an aliphatic diisocyanate and / or an alicyclic diisocyanate.
3. The method according to claim 1 or 2,
(a3-1) having 5 to 10 carbon atoms in total.
3. The method according to claim 1 or 2,
wherein the component (a3-2) comprises 2-isocyanatoethyl (meth) acrylate and / or 1,1- (bisacryloyloxymethyl) ethyl isocyanate.
3. The method according to claim 1 or 2,
Wherein the average number of (meth) acryloyl groups of the component (A) is from 1.5 to 4.
3. The method according to claim 1 or 2,
(A) has a weight average molecular weight of 10,000 to 90,000.
3. The method according to claim 1 or 2,
(B) is an alkyl mono (meth) acrylate having an alkyl group having 4 to 18 carbon atoms.
A cured product (cured product) comprising the ultraviolet curable pressure-sensitive adhesive of any one of claims 1 to 3.
10. The method of claim 9,
A storage elastic modulus G 'at a temperature of -20 ° C and 1 Hz of 1 × 10 ⁶ Pa or less, and a storage elastic modulus G' at 25 ° C and 1 Hz of 1 × 10 ⁵ Pa or less.
A pressure sensitive adhesive sheet (adhesive sheet) comprising the cured product of claim 9 on at least one side of a substrate.