JP2016053113A - Optical adhesive composition, manufacturing method therefor, application method therefor and optical adhesive sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical adhesive composition capable of providing an adhesive layer excellent in transparency and moisture heat whitening resistance, an application method therefor, a manufacturing method of the optical adhesive composition, and an optical adhesive sheet.SOLUTION: An optical adhesive composition contains a (meth)acrylic resin (A), a monomer mixture (m) and a crosslinking agent (B), the monomer mixture (m) contains (ma) 45 mass% to 94.9 mass% of an acrylic monomer having an alkyl group having 1 to 18 carbon atoms, (mb) 5 mass% to 45 mass% of an acrylic monomer having a hydroxyl group, and (mc) 0.1 mass% to 10 mass% of N-vinylcarboxylic acid amide, on the basis of 100 mass% of the monomer mixture (m). The (meth)acrylic monomer (A) is a copolymer of monomer components containing (a1) an acrylic monomer (A1) having an alkyl group having 1 to 18 carbon atoms and (a2) an acrylic monomer (A2) having a hydroxyl group.SELECTED DRAWING: None

Description

  The present invention relates to an optical adhesive composition, a method for producing the same, a method for using the same, and an optical pressure-sensitive adhesive sheet.

  In recent years, in an adhesive composition used for bonding members requiring transparency, high transparency has been demanded in the same manner as members. For example, a pressure-sensitive adhesive sheet obtained from a syrup-like adhesive composition (for example, see Patent Document 1) containing a monomer containing a polar group (for example, a hydroxyl group) is less likely to be clouded even in a high temperature and high humidity environment. Are known.

  However, a syrup-like adhesive composition containing a monomer having a polar group such as a hydroxyl group tends to cause turbidity in the varnish due to aggregation of the polymer components, and the turbid syrup The pressure-sensitive adhesive sheet obtained using the adhesive composition tends to be clouded. For this reason, a syrup-like adhesive composition containing a monomer having a polar group such as a hydroxyl group may be difficult to use for applications requiring high transparency.

JP 2001-181589 A

  The present invention provides an optical adhesive composition capable of obtaining an adhesive layer excellent in transparency and moisture and heat whitening resistance, a method for producing the same, a method for using the same, and an optical pressure-sensitive adhesive sheet.

  In order to solve such problems, the present inventors can use an adhesive composition having N-vinylcarboxylic acid amide to make a syrup-like adhesive composition excellent in transparency, And it discovered that the adhesive layer excellent in transparency and moisture-and-heat whitening resistance was obtained.

  1. An optical adhesive composition according to an aspect of the present invention includes a (meth) acrylic resin (A), a monomer mixture (m), and a crosslinking agent (B), and the monomer mixture. When (m) is 100% by mass of the monomer mixture (m), (ma) (meth) acrylic monomer having an alkyl group having 1 to 18 carbon atoms is 45% by mass to 94.9%. (Mb) a (meth) acrylic monomer having a hydroxyl group of 5% by mass to 45% by mass, (mc) N-vinylcarboxylic acid amide 0.1% by mass to 10% by mass, The (meth) acrylic resin (A) includes (a1) a (meth) acrylic monomer (A1) having an alkyl group having 1 to 18 carbon atoms, and (a2) a hydroxyl group ( A copolymer of monomer components including a (meth) acrylic monomer (A2) That.

  2. In the optical adhesive composition described in 1 above, the (meth) acrylic resin (A) may have a weight average molecular weight of 10,000 or more and 800,000 or less.

・・・・・（１）
（式中、Ｒ^１は水素原子または炭素原子数１以上４以下のアルキル基を表し、Ｒ^２は炭素原子数１以上４以下のアルキル基を表す。） 3. In the optical adhesive composition according to 1 or 2, the N-vinylcarboxylic acid amide (mc) can be represented by the following formula (1).

(1)
(Wherein R ¹ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and R ² represents an alkyl group having 1 to 4 carbon atoms.)

  4). 4. The optical adhesive composition according to any one of 1 to 3, wherein the amount of the monomer mixture (m) is 10 parts by mass with respect to 100 parts by mass of the (meth) acrylic resin (A). The amount can be 1,000 parts by mass or more.

  5. 5. The optical adhesive composition according to any one of 1 to 4 above, wherein the acid values of the (meth) acrylic resin (A) and the monomer mixture (m) are both 1.0 or less. Can do.

6). The manufacturing method of the optical adhesive composition which concerns on 1 aspect of this invention is a method of manufacturing the optical adhesive composition in any one of said 1 thru | or 5, Comprising:
(Meth) acrylic monomer (a1) having an alkyl group having 1 to 18 carbon atoms, and (meth) acrylic monomer (b1) having a hydroxyl group in a system substantially free from a solvent, A step of polymerizing a part of the monomer mixture (m1) containing a partial copolymer (P);
(Meth) acrylic monomer (a2) having an alkyl group having 1 to 18 carbon atoms, (meth) acrylic monomer (b2) having a hydroxyl group, N-vinylcarboxylic acid amide (c2), A step of adding a monomer mixture (m2) containing: to the partial polymer (P);
including.

  7). The method for using the optical adhesive composition according to one aspect of the present invention includes a step of adding a photopolymerization initiator (PI) to the optical adhesive composition described in any one of 1 to 5 above.

  8). The optical pressure-sensitive adhesive sheet according to one embodiment of the present invention is obtained by applying the optical adhesive composition described in any one of 1 to 5 above to the surface of a separator and irradiating with light.

  9. The optical pressure-sensitive adhesive sheet described in 8 above can be used for bonding members constituting a touch panel type input / output device or an image display device.

  The optical adhesive composition according to any one of 1 to 5 above includes a (meth) acrylic resin (A), a monomer mixture (m), and a crosslinking agent (B). Due to the N-vinylcarboxylic amide (mc) contained in the monomer mixture (m), the compatibility between the (meth) acrylic resin (A) and the monomer mixture (m) is increased. Therefore, the composition (varnish) is excellent in transparency. In addition, an adhesive layer prepared using the optical adhesive composition is excellent in transparency and moisture and heat whitening resistance.

  6. The method for producing an optical adhesive composition according to 6 above is a method for producing the optical adhesive composition according to any one of 1 to 5 above, wherein the optical adhesive composition is substantially free from a solvent. A monomer mixture (m1) containing a (meth) acrylic monomer (a1) having an alkyl group having 1 to 18 carbon atoms and a (meth) acrylic monomer (b1) having a hydroxyl group. A step of polymerizing a part to obtain a partial copolymer (P), a (meth) acrylic monomer (a2) having an alkyl group having 1 to 18 carbon atoms, and a (meth) acrylic monomer having a hydroxyl group. A step of adding a monomer mixture (m2) containing a monomer (b2) and an N-vinylcarboxylic acid amide (c2) to the partial polymer (P), thereby providing excellent transparency. An adhesive layer can be obtained.

  Since the optical pressure-sensitive adhesive sheet according to 8 and 9 is obtained by applying the optical adhesive composition according to any one of 1 to 5 above to the surface of the separator and irradiating it with light, transparency and heat resistance to moisture Excellent whitening property. Therefore, the optical pressure-sensitive adhesive sheet can be suitably used for, for example, applications (more specifically, image display devices and input / output devices) that require transparency and wet heat whitening resistance.

FIG. 1 is a cross-sectional view schematically showing an input / output device (touch panel type input / output device) including an adhesive layer obtained from an optical adhesive composition according to an embodiment of the present invention. FIG. 2 is a schematic view showing a member configuration of an image display device including an adhesive layer obtained from the optical adhesive composition according to one embodiment of the present invention. 3A, FIG. 3B, and FIG. 3C are schematic views showing one manufacturing process of the image display device shown in FIG.

  Hereinafter, the present invention will be described in detail with reference to the drawings. In the present invention, “parts” means “parts by mass” and “%” means “mass%” unless otherwise specified.

1. Optical adhesive composition (first embodiment)
The optical adhesive composition according to an embodiment of the present invention (hereinafter sometimes simply referred to as “adhesive composition”) is a (meth) acrylic resin (A) (hereinafter simply referred to as “(A ) Component ”), monomer mixture (m) (hereinafter sometimes simply referred to as“ (m) component ”), and crosslinking agent (B) (hereinafter simply referred to as“ component ”). (B) may be described as “component”).

  According to the optical adhesive composition according to this embodiment, the N-vinyl contained in the monomer mixture (m) is obtained by including the (meth) acrylic resin (A) and the monomer mixture (m). Due to the carboxylic acid amide (mc), the compatibility between the (meth) acrylic resin (A) and the monomer mixture (m) can be improved, so that excellent transparency can be achieved. An adhesive layer having high transparency can be obtained using the adhesive composition.

  In the present invention, “bonding” is a concept including “adhesion”. Further, the optical adhesive composition according to the present embodiment may be an optical adhesive composition that substantially does not contain a solvent (solvent-free type). Here, “the composition is substantially free of solvent” means that the content of the solvent in the composition is, for example, 1% by mass or less, more preferably 0.5% by mass or less, and ideally the solvent is composed of This means that it is not blended with the product.

  In the present invention, the “solvent” means a reactive double having a property capable of dissolving the (meth) acrylic resin (A), the monomer mixture (m), and the crosslinking agent (B). A liquid that does not have a bond. As the solvent, for example, those generally used for polymer solution polymerization are preferable.

  As will be described later, the optical adhesive composition according to this embodiment is a (meth) acrylic resin (A) manufactured in a solvent-free system (a system that substantially does not contain a solvent, for example, a system that does not contain a solvent). ) And monomer mixture (m).

1.1. (Meth) acrylic resin (A)
The (meth) acrylic resin (A) is a copolymer derived from a monomer component. More specifically, the (meth) acrylic resin (A) is a (meth) acrylic monomer (A1) having an alkyl group having 1 to 18 carbon atoms (hereinafter simply referred to as “component (A1)”). And a (meth) acrylic monomer (A2) having a hydroxyl group (hereinafter sometimes simply referred to as “component (A2)”). It can be a (meth) acrylic copolymer derived from a body component.

In the present invention, the term “(metha) acrylic” is a concept including both acrylic and methacrylic. In the present invention, the (meth) acrylic monomer means an acryloyl group (H ₂ C═CH—C (═O) —) and / or a methacryloyl group (H ₂ C═C (CH ₃ ) —C. A monomer having (= O)-)). Further, in the present invention, the (meth) acrylic _{resin, -H 2 C-CH (-} ) - C (= O) - structural units represented by and / or _{-H 2 C-C (CH 3} ) A resin containing a structural unit represented by (−) — C (═O) —.

1.1.1. Monomer component 1.1.1.1-1. (A1) component (A1) A component can contribute to the adhesiveness and durability of the optical adhesive composition which concerns on this embodiment. That is, the adhesiveness and durability of the adhesive composition can be enhanced by copolymerizing a monomer component containing the component (A1) to obtain the component (A).

Examples of the component (A1) include (meth) acrylic acid alkyl esters having an alkyl group having 1 to 18 carbon atoms. For example, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, n- Propyl acrylate, n-propyl methacrylate, n-butyl acrylate, n-butyl methacrylate, n-pentyl acrylate, n-hexyl acrylate, n-hexyl methacrylate, n-heptyl acrylate, n-heptyl methacrylate, n-octyl acrylate, n- Octyl methacrylate, n-nonyl acrylate, n-decyl acrylate, n-decyl methacrylate, lauryl methacrylate, lauryl acrylate, n-tetradecyl methacrylate, n Tetradecyl methacrylate, n- hexadecyl acrylate, n- hexadecyl methacrylate, stearyl acrylate, (meth) acrylic acid alkyl ester having a linear alkyl group such as stearyl methacrylate;
Isopropyl acrylate, isobutyl acrylate, tert-butyl acrylate, isopropyl methacrylate, isobutyl methacrylate, tert-butyl methacrylate, isoamyl acrylate, isoamyl methacrylate, isooctyl acrylate, isooctyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, isodecyl acrylate, (Meth) acrylic acid alkyl ester having a branched alkyl group such as isodecyl methacrylate, isostearyl acrylate, isostearyl methacrylate;
Examples include (meth) acrylic acid alkyl esters having an alicyclic alkyl group such as cyclohexyl acrylate, cyclohexyl methacrylate, isobornyl acrylate, and isobornyl methacrylate, and one of these is used alone or in combination of two or more. You can also

  Among these, the component (A1) is an acrylic having a linear or branched alkyl chain in that the pressure-sensitive adhesive sheet formed using the optical adhesive composition according to this embodiment is excellent in durability. An acid alkyl ester is preferred.

1.1.1-2. (A2) component (meth) acrylic resin (A) is a copolymer of the monomer component containing (A2) component, and this embodiment originates in the hydroxyl group resulting from (A2) component. When the adhesive layer obtained from the optical adhesive composition according to the present invention is exposed to high temperature and high humidity, the hydroxyl group disperses moisture in the adhesive layer, thereby preventing the occurrence of haze. be able to. That is, by obtaining a (meth) acrylic resin (A) by copolymerizing a monomer component containing the component (A2), the adhesive composition can be used even when exposed to high temperatures and high humidity. The transparency of the resulting adhesive layer can be maintained.

  Examples of the component (A2) include a (meth) acrylic acid alkyl ester having a hydroxyl group, such as 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate. It is preferably a (meth) acrylic acid alkyl ester having a hydroxyalkyl group having 1 to 4 carbon atoms, such as 4-hydroxybutyl acrylate, 4-hydroxybutyl methacrylate, etc. It can also be used in combination. Especially, as (A2) component, it is more preferable that they are 2-hydroxyethyl methacrylate and 4-hydroxybutyl acrylate, or any one.

1.1.1-3. (A3) Component The (meth) acrylic resin (A) is a structural unit derived from the N-vinylcarboxylic acid amide (A3) represented by the following formula (1) (hereinafter simply referred to as “(A3) component”). May be included). That is, the (meth) acrylic resin (A) is a (meth) acrylic copolymer derived from a monomer component that further includes the component (A3) in addition to the components (A1) and (A2). Also good.

・・・・・（１）
（式中、Ｒ^１は水素原子または炭素原子数１以上４以下のアルキル基を表し、Ｒ^２は炭素原子数１以上４以下のアルキル基を表す。）

(1)
(Wherein R ¹ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and R ² represents an alkyl group having 1 to 4 carbon atoms.)

  The structural unit derived from the component (A3) is, for example, a repeating unit represented by the following formula (2).

・・・・・（２）
（式中、Ｒ^１は水素原子または炭素原子数１以上４以下のアルキル基を表し、Ｒ^２は炭素原子数１以上４以下のアルキル基を表す。）

(2)
(Wherein R ¹ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and R ² represents an alkyl group having 1 to 4 carbon atoms.)

In the above formulas (1) and (2), examples of the alkyl group having 1 to 4 carbon atoms that is R ¹ or R ² include linear or branched alkyl groups having 1 to 4 carbon atoms. Examples thereof include a methyl group, an ethyl group, an isopropyl group, an n-propyl group, an n-butyl group, and an isobutyl group. In terms of excellent hydrophilicity and copolymerizability with the (meth) acrylic monomer, R ¹ is preferably a hydrogen atom, and R ² is preferably a methyl group.

  In this case, the proportion of the component (A3) contained in the monomer component for preparing the (meth) acrylic resin (A) is 0.3% by mass or less (preferably 0.2% by mass or less, more preferably 0.1% by mass or less) is preferable. As the component (A3), for example, those exemplified in the column of N-vinylcarboxylic acid amide (mc) described later can be used.

  In addition, the (A3) component usually has lower polymerization reactivity than the (A1) component and the (A2) component when copolymerized with the (A1) component, the (A2) component, and the (A3) component. Therefore, the (meth) acrylic resin (A) may be a copolymer derived from a monomer component in which the content of the component (A3) is in the above-described range, and more preferably, (A3) The copolymer derived from the monomer component which does not contain a component may be sufficient.

1.1.1-4. Other monomers (A4)
The (meth) acrylic resin (A) may be described as a monomer (A4) other than the (A1) component, the (A2) component, and the (A3) component (hereinafter simply referred to as “(A4) component”). ) -Containing monomer component-containing copolymer. The content ratio of the component (A4) in the monomer component is preferably 0% by mass or more and 10% by mass or less. As the component (A4), for example, (meth) acrylic acid ester having an aromatic ring group such as benzyl methacrylate, benzyl acrylate, 2-naphthyl acrylate, phenoxyethyl acrylate, styrene, α-methylstyrene, o-methylstyrene, p -Styrene monomers such as methylstyrene; carboxylic acid vinyl esters such as vinyl acetate; vinyl (meth) acryloyl group-containing macromonomers; carboxyl group-containing monomers such as (meth) acrylic acid, fumaric acid, and maleic acid It is done.

1.1.1-5. Ratio and total amount of component (A1) and component (A2) In the optical adhesive composition according to this embodiment, from the viewpoint of obtaining higher transparency, in the (meth) acrylic resin (A), ) When the monomer component for obtaining the acrylic resin (A) is 100% by mass, the proportion of the component (A1) is 45% by mass to 95% by mass (preferably 70% by mass to 90% by mass). It is preferable that the ratio of the component (A2) is 5% by mass or more and 45% by mass or less (preferably 10% by mass or more and 30% by mass or less).

  In the optical adhesive composition according to the present embodiment, from the viewpoint that good adhesiveness and durability can be more reliably achieved, (A1 in the monomer component for obtaining in (meth) acrylic resin (A) The total amount of component (A) and component (A2) can be 90% by mass to 100% by mass, and preferably 95% by mass to 100% by mass.

1.1.2. Molecular Weight In the optical adhesive composition according to this embodiment, the (meth) acrylic resin (A) has a weight average molecular weight (Mw) of 10,000 to 800,000, preferably 50,000 to 700, 000 or less, more preferably 150,000 or more and 700,000 or less.

  When the weight average molecular weight of the (meth) acrylic resin (A) is less than 10,000, the durability of the adhesive layer obtained using the adhesive composition may be inferior, while 800,000 is used. When it exceeds, compatibility with (meth) acrylic-type resin (A) and a monomer mixture (m) will fall in this adhesive composition, and turbidity and phase separation may be produced.

  In the present invention, “turbidity” means that the syrup-like adhesive composition or adhesive layer is visually confirmed to be not transparent. Further, in the present invention, “becoming clouded” means that an adhesive layer (pressure-sensitive adhesive sheet) that is not visually turbid is heated under heating conditions (particularly, under high temperature and high humidity conditions (for example, implementation described later). By setting it at a temperature of 65 ° C. and a humidity of 95% as described in the examples, it means that the adhesive layer (pressure-sensitive adhesive sheet) becomes turbid visually.

  Further, “moisture and heat whitening resistance” in the present invention means that the transparency of the adhesive layer is lowered when the adhesive layer is exposed to wet heat conditions (high temperature and high humidity conditions). The decrease in the transparency of the adhesive layer can be confirmed by an increase in the haze of the adhesive layer after exposure to wet heat conditions relative to the haze of the adhesive layer before exposure to wet heat conditions. In addition, the measurement of the haze of an adhesive bond layer can be measured by the method described in the Example mentioned later.

  Here, the weight average molecular weight (Mw) and the number average molecular weight (Mn) of the (meth) acrylic resin (A) were obtained by standard polystyrene conversion using GPC (gel permeation chromatography) under the following conditions. Value.

<GPC measurement conditions>
Measuring device: HLC-8120GPC (manufactured by Tosoh Corporation)
GPC column configuration: The following five columns (all manufactured by Tosoh Corporation)
(1) TSK-GEL HXL-H (guard column)
(2) TSK-GEL G7000HXL
(3) TSK-GEL GMHXL
(4) TSK-GEL GMHXL
(5) TSK-GEL G2500HXL
Diluted with tetrahydrofuran so that the sample concentration is 1.0 mg / cm ³ Mobile phase solvent: Tetrahydrofuran Flow rate: 1.0 cm ³ / min
Column temperature: 40 ° C

1.1.3. Dispersion (Mw / Mn)
In the optical adhesive composition according to this embodiment, the molecular weight dispersion (Mw / Mn) of the (meth) acrylic resin (A) is preferably 4.5 or less, and usually 1 or more and 4.5 or less. Yes, it is more preferably 1 or more and 4.3 or less. When the molecular weight dispersion (Mw / Mn) of the (meth) acrylic resin (A) exceeds 4.5, the (meth) acrylic resin (A) and the monomer mixture (m) in the adhesive composition As a result, the adhesive composition may become turbid.

1.1.4. Transparency (turbidity)
The optical adhesive composition according to this embodiment is a syrupy transparent liquid. In the optical adhesive composition according to this embodiment, turbidity is an index of transparency, and the lower the turbidity, the higher the transparency. The turbidity of the optical adhesive composition according to this embodiment is preferably 5.0 or less, and more preferably 2.0 or less.

1.1.5. Acid Value The acid value of the (meth) acrylic resin (A) is preferably 1.0 or less, and more preferably 0.8 or less, from the viewpoint that the corrosivity of ITO can be prevented. In this case, the (meth) acrylic resin (A) preferably has substantially no carboxyl group.

  Here, “(meth) acrylic resin (A) substantially has no carboxyl group” means more specifically in the monomer component constituting (meth) acrylic resin (A). The content ratio of the monomer having a carboxyl group is 0.1% by mass or less.

1.2. Monomer mixture (m)
When the monomer mixture (m) is 100% by mass of the monomer mixture (m), (ma) a (meth) acrylic monomer having an alkyl group having 1 to 18 carbon atoms (hereinafter, And may be simply described as “(ma) component”.) 45% by mass or more and 94.9% by mass or less and (mb) (meth) acrylic monomer having a hydroxyl group 5% by mass or more and 45% by mass or less. (Hereinafter sometimes simply referred to as “(mb) component”) and (mc) N-vinylcarboxylic acid amide 0.1% by mass to 10% by mass (hereinafter simply referred to as “(mc) component”) In some cases).

  From the viewpoint of obtaining higher transparency, when the monomer mixture (m) is 100% by mass in the monomer mixture (m), the ratio of the (meth) acrylic monomer (ma) is: It is 55 mass% or more and 94.5 mass% or less, the ratio of (meth) acrylic-type monomer (mb) is 10 mass% or more and 35 mass% or less, and the ratio of (mc) component is 0.5. It is preferable that they are 10 mass% or less.

  The proportions of the components (ma), (mb), and (mc) in the monomer mixture (m) are identified by, for example, performing gas chromatography analysis on the optical adhesive composition according to the present embodiment. can do.

1.2.1. (Ma) Component As the (ma) component, for example, those exemplified as the above-described (A1) component can be used. The component (ma) is preferably the same (meth) acrylic monomer as the component (A1).

1.2.2. (Mb) Component As the (mb) component, for example, those exemplified as the component (A2) described above can be used. The component (mb) is preferably the same (meth) acrylic monomer having a hydroxyl group as the component (A2).

1.2.3. Component (mc) Component (mc) is an optical adhesive composition (varnish) according to the present embodiment, which prevents turbidity, and an adhesive layer (pressure-sensitive adhesive sheet) formed from the composition under high temperature and high humidity conditions. This can contribute to the suppression of haze value rise and the improvement of adhesive strength. That is, when the monomer mixture (m) has the component (mc), the transparency of the adhesive composition can be increased and the adhesive composition can have excellent adhesive strength. It is possible to produce an adhesive layer excellent in transparency and moisture and heat whitening resistance.

  The N-vinylcarboxylic acid amide as the component (mc) is represented by the general formula (1). The component (mc) may be the same N-vinylcarboxylic acid amide as the component (A3).

  Examples of the N-vinylcarboxylic amide as the component (mc) include N-vinylformamide, N-methyl-N-vinylformamide, N-ethyl-N-vinylformamide, N-propyl-N-vinylformamide, N -Isopropyl-N-vinylformamide, N-butyl-N-vinylformamide, N-isobutyl-N-vinylformamide, N-vinylacetamide, N-methyl-N-vinylacetamide, N-ethyl-N-vinylacetamide, N -Propyl-N-vinylacetamide, N-isopropyl-N-vinylacetamide, N-butyl-N-vinylacetamide, N-isobutyl-N-vinylacetamide, N-vinylpropionic amide, N-methyl-N-vinyl Propionic amide, N-ethyl-N-vinyl group Pionic amide, N-propyl-N-vinyl propionic amide, N-isopropyl-N-vinyl propionic amide, N-butyl-N-vinyl propionic amide, N-isobutyl-N-vinyl propionic Amide, N-vinyl butyric amide, N-methyl-N-vinyl butyric amide, N-ethyl-N-vinyl butyric amide, N-propyl-N-vinyl butyric amide, N-butyl-N-vinyl butyric Rick amide, N-isobutyl-N-vinyl butyric amide, N-methyl-N-vinyl isobutyric amide, N-ethyl-N-vinyl isobutyric amide, N-propyl-N-vinyl isobutyric amide, N-isopropyl-N-vinylisobutyric amide, N-isopropyl-N-vinylbutyrica , N-vinyl isobutyric amide, N-butyl-N-vinyl isobutyric amide, N-isobutyl-N-vinyl isobutyric amide, etc., of which one or a combination of two or more Can be used. Among these, the (mc) component is N-vinylacetamide and N-vinyl-N-methylacetamide or one of them in that the aggregation suppressing effect of the (meth) acrylic resin (A) is more excellent. N-vinylacetamide is more preferable.

1.2.4. Compounding ratio of (meth) acrylic resin (A) and monomer mixture (m) In the optical adhesive composition according to this embodiment, (meth) acrylic resin (A) and monomer mixture (m ), The monomer mixture (m) is preferably 10 parts by weight or more and 1,000 parts by weight or less, based on 100 parts by weight of the (meth) acrylic resin (A), and 50 parts by weight. It is more preferably 700 parts by mass or less, and further preferably 100 parts by mass or more and 500 parts by mass or less. If the blending ratio is within the above range, the optical adhesive composition according to the present embodiment is preferable because it has an appropriate viscosity and is easy to handle.

1.2.5. Acid Value The acid value of the monomer mixture (m) is preferably 1.0 or less, and more preferably 0.8 or less, from the viewpoint that the corrosivity of ITO can be prevented.

  In the optical adhesive composition according to this embodiment, it is preferable that the acid values of the (meth) acrylic resin (A) and the monomer mixture (m) are both 1.0 or less.

  Moreover, it is preferable that the optical adhesive composition according to this embodiment does not substantially contain a monomer having a carboxyl group. “The optical adhesive composition according to this embodiment is substantially free of a monomer having a carboxyl group” means that the carboxyl group contained in the optical adhesive composition according to this embodiment is included. It means that the ratio of the monomer is 0.1% by mass or less.

1.3. Cross-linking agent (B)
Examples of the crosslinking agent (B) used in the optical adhesive composition according to this embodiment include trimethylolpropane tri (meth) acrylate, hexanediol di (meth) acrylate, polyethylene diol di (meth) acrylate, Examples thereof include polyfunctional (meth) acrylate compounds such as polypropylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, pentaerythritol di (meth) acrylate, and dipentaerythritol hexa (meth) acrylate.

  Moreover, when the optical adhesive composition according to the present embodiment contains a polymerizable monomer having an amino group, a hydroxyl group, or a carboxyl group, a crosslinking agent (B) that can react with these functional groups. Can be used. In addition, when the optical adhesive composition which concerns on this embodiment does not contain the polymerizable monomer which has a carboxyl group, a crosslinking agent (B) does not need to react with a carboxyl group.

  Examples of such a crosslinking agent (B) include ethylene diglycidyl ether, polyethylene glycol diglycidyl ether, glycerin diglycidyl ether, glycerin triglycidyl ether, 1,6-hexanediol glycidyl ether, trimethylolpropane triglycidyl ether, It has an epoxy group such as diglycidyl aniline, diamine glycidyl amine, N, N, N ′, N′-tetraglycidyl-m-xylylenediamine, 1,3-bis (N, N′-diamine glycidylaminomethyl) cyclohexane Compound, Tolylene diisocyanate, Hexamethylene diisocyanate, Isophorone diisocyanate, Xylylene diisocyanate, Isophorone diisocyanate, Diphenylmethane isocyanate, Tetramethyl Xylylene diisocyanate, naphthalene diisocyanate, triphenylmethane triisocyanate, may be a compound having an isocyanate group such as polymethylene polyphenyl isocyanate. Examples of the crosslinking agent (B) having such an isocyanate group include a product name “Coronate L” manufactured by Nippon Polyurethane Co., Ltd.

  The blending amount of the crosslinking agent (B) is preferably 0.01 parts by mass or more and 5 parts by mass or less, and 0.01 parts by mass or more and 3 parts by mass with respect to 100 parts by mass of the (meth) acrylic resin (A). The following is more preferable.

1.4. Other components The optical adhesive composition according to the present embodiment further includes components other than the (meth) acrylic resin (A), the monomer mixture (m), and the crosslinking agent (B) as necessary. be able to. For example, the optical adhesive composition according to the present embodiment includes a silane coupling agent, an ionic compound, an antioxidant, an ultraviolet absorber, a tackifier, a plasticizer, and the like as long as the effects of the present invention are not impaired. May be blended.

1.5. Method for Producing Optical Adhesive Composition The optical adhesive composition according to this embodiment can be produced in a reaction system that does not substantially contain a solvent. More specifically, the optical adhesive composition according to this embodiment can be produced by the following first step and second step.

  First step: (meth) acrylic monomer (a1) having an alkyl group having 1 to 18 carbon atoms in a system substantially free from a solvent (hereinafter simply referred to as “component (a1)”) And a (meth) acrylic monomer (b1) having a hydroxyl group (hereinafter sometimes simply referred to as “component (b1)”), and a monomer mixture (m1) (Hereinafter, it may be simply referred to as “(m1) component”). A step of obtaining a partial copolymer (P) by polymerizing a part thereof, and a single amount obtained from the monomer mixture (m1) A step of preparing a mixture (m ′) with the body residue (r) (in addition, the monomer mixture (m1) may contain N-vinylcarboxylic acid amide (c1)).

  Second step: A (meth) acrylic monomer (a2) having an alkyl group having 1 to 18 carbon atoms (hereinafter sometimes simply referred to as “component (a2)”) and a hydroxyl group. (Meth) acrylic monomer (b2) (hereinafter sometimes simply referred to as “(b2) component”) and N-vinylcarboxylic acid amide (c2) (hereinafter simply referred to as “(c2) component”) And a monomer mixture (m2) (hereinafter sometimes simply referred to as “(m2) component”), which is added to the mixture (m ′).

  Here, as the component (a1) and the component (a2), the same component as the component (A1) can be used, and as the component (b1) and the component (b2), the component (A2) described above can be used. The same thing can be used, and the same thing as the above-mentioned (A3) component can be used as (c1) component and (c2) component.

  The monomer mixture (m1) may contain a component other than the component (a1), the component (b1), and the component (c1) (component (d1)). Moreover, the monomer mixture (m2) may contain components (component (d2)) other than the components (a2), (b2) and (c2). Examples of the component (d1) and the component (d2) include the monomers exemplified as the component (A4) described above.

  In the first step, the component (c1) is less reactive than the component (a1), and therefore, it tends to be difficult to be incorporated into the polymer chain constituting the acrylic resin (A). Therefore, when the monomer mixture (m1) contains the component (c1), the proportion of the component (c1) in the monomer mixture (m1) It is preferable that it is less than the ratio of the component (c2) in the monomer mixture (m2).

1.5.1. First Step In the first step, the monomer mixture (m1) is 100% by mass in the monomer mixture (m1) from the viewpoint of improving the transparency of the finally obtained adhesive composition. In this case, the proportion of the component (a1) is 60% by mass to 95% by mass (more preferably 60% by mass to 90% by mass), and the proportion of the component (b1) is 5% by mass to 40% by mass. (More preferably, it is 10 mass% or more and 40 mass% or less).

  Here, when the monomer mixture (m1) includes the component (c1), the proportion of the component (c1) in the monomer mixture (m1) is 0.5% by mass or less (preferably 0.3% by mass or less). It is preferable that

  In the first step, a polymerization initiator (I) can be used. In the first step, in order to polymerize only a part of the monomer mixture (m1), the amount of the polymerization initiator (I) used is 0.001 part by mass of 100 parts by mass of the monomer mixture (m1). The content is preferably 0.1 parts by mass or less (more preferably 0.0015 parts by mass or more and 0.5 parts by mass or less). In the first step, in order to polymerize only a part of the monomer mixture (m1), the reaction system is set within 30 minutes (preferably within 15 minutes) after the polymerization of the monomer mixture (m1). The progress of polymerization may be suppressed by cooling.

  Further, by approximating the composition of the (meth) acrylic resin (A) and the composition of the monomer mixture (m) in the finally obtained adhesive composition to some extent, the (meth) acrylic resin (A ) And the monomer mixture (m) from the viewpoint of enhancing the compatibility of the monomer mixture (m2) in the first step, the amount of the monomer mixture (m1) is 100 parts by mass. 5 parts by mass or more and 100 parts by mass or less, preferably 5 parts by mass or more and 50 parts by mass or less, and more preferably 10 parts by mass or more and 30 parts by mass or less.

  Examples of the polymerization initiator (I) used in the first step include isobutyryl peroxide, α, α′-bis (neodecanoylperoxy) diisopropylbenzene, cumylperoxyneodecanoate, di- n-propyl peroxydicarbonate, diisopropyl peroxydicarbonate, di-sec-butyl peroxydicarbonate, 1,1,3,3-tetramethylbutylperoxyneodecanoate, bis (4-butylcyclohexyl) per Mention may be made of oxydicarbonate and 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile). These polymerization initiators (I) can be used alone or in combination.

  Among these, isobutyryl peroxide, α, α′-bis (neodecanoylperoxy) diisopropylbenzene, cumylperoxyneodecanoate, 2,2′-azobis (4-methoxy-2,4-dimethylvalero) Nitrile) is preferably used, and 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile) is particularly preferably used.

  By using the polymerization initiator (I) in the first step, a (meth) acrylic copolymer (partial) in which 10% by mass or more and 67% by mass or less of the monomer mixture (m1) as a raw material has been polymerized. Copolymer (P)) can be obtained. Next, by adding the monomer mixture (m2) in the second step, the optical adhesive having excellent transparency comprising the (meth) acrylic resin (A) and the monomer mixture (m). An agent composition can be obtained.

  The temperature of the monomer mixture (m1) when adding the polymerization initiator (I) is usually in the range of 20 ° C. to 80 ° C., preferably 35 ° C. to 70 ° C., particularly preferably 40 ° C. to 65 ° C. Is in. The polymerization initiator (I) is usually added with stirring to the monomer mixture (m1) thus heated or heated.

  The above example is an example in which the monomer mixture (m1) is heated and the polymerization initiator (I) is added. The mixing and heating of the monomer mixture (m1) and the polymerization initiator (I) Can be done in any order. For example, after the monomer mixture (m1) and the polymerization initiator (I) are mixed, the mixture can be heated to a temperature at which the reaction starts, or the monomer mixture (m1) can be heated as described above. After heating to a temperature at which the reaction starts, the polymerization initiator (I) can be added and mixed.

  In the first step, in addition to the specific polymerization initiator (I) described above, a chain transfer agent such as normal dodecyl mercaptan, butyl mercaptan, 3-mercaptopropionic acid, thioglycolic acid or thioglycolic acid ester is used in combination. You may do it. Such chain transfer agent is usually 0.001 part by mass or more and 10 parts by mass or less, preferably 0.01 part by mass or more and 0.5 parts by mass or less, with respect to 100 parts by mass of the monomer mixture used. Used in amounts within the range.

1.5.2. Second Step In the second step, a monomer mixture (m2) is added to the mixture (m ′) obtained in the first step, and the mixture (m ′) and the monomer mixture (m2) are added. And mix. Thereby, the optical adhesive composition excellent in transparency containing (meth) acrylic-type resin (A) and a monomer mixture (m) is obtained.

  In the second step, in the monomer mixture (m2), the proportion of the component (a2) is 50% by mass or more and 89% by mass from the viewpoint of further improving the transparency of the finally obtained adhesive composition. It is preferable that the proportion of the component (b2) is 10% by mass or more and 40% by mass or less, and the proportion of the component (c2) is 1% by mass or more and 10% by mass or less. The total of the component (a2), the component (b2) and the component (c2) is preferably 90% by mass or more and 100% by mass or less when the component (m2) is 100% by mass. Moreover, it is preferable that the compounding part number of (m2) component with respect to (m1) component is 5 to 50 mass parts, when (m1) component is 100 mass parts.

  In addition, it is preferable to use block polymerization in the said 1st process for manufacture of (meth) acrylic-type resin (A). That is, in the first step, polymerization is carried out substantially without using a solvent.

  The polymerization reaction in the first step is preferably performed with stirring, and the reaction is preferably performed in an inert atmosphere such as nitrogen gas. Furthermore, since oxygen dissolved in the raw material used may hinder the progress of the reaction, it is preferable to use it after removing dissolved oxygen in the raw material used.

1.5.3. Effects of Production Method According to the production method described above, (meth) acrylic having excellent compatibility due to the N-vinylcarboxylic acid amide contained in the system by including the first step and the second step. Producing an optical adhesive composition that includes an epoxy resin (A) and a monomer mixture (m), and that is capable of obtaining an adhesive layer that is excellent in transparency and moisture and heat whitening resistance. it can.

  Moreover, in the said manufacturing method, since it is not necessary to remove a solvent by performing the said 1st process and 2nd process in the system which does not contain a solvent substantially, the effort of a manufacturing process can be saved.

  Furthermore, in the said manufacturing method, a uniform syrup-like optical adhesive composition can be obtained by performing the said 1st process and 2nd process in the system which does not contain a solvent substantially.

1.6. Applications The optical adhesive composition according to the present embodiment can be used for bonding optical members, and in particular, can be suitably used for bonding optical members that require transparency.

  A member to be bonded using the optical adhesive composition according to the present embodiment is an optical member (for example, a polarizing film, a retardation film, an elliptically polarizing film, an antireflection film, a brightness enhancement film, a light diffusion film). And an optical film selected from the group consisting of hard coat films), a metal layer such as an ITO layer, or a substrate made of glass or plastic.

1.6.1. I / O Device The optical adhesive composition according to the present embodiment can be used for bonding members constituting a touch panel type input / output device or an image display device, for example. The example which used the adhesive composition for optics which concerns on this embodiment for the bonding of the member which comprises a touchscreen type input / output apparatus is demonstrated with reference to FIG.

  FIG. 1 is a cross-sectional view schematically showing an input / output device (touch panel type input / output device) including an adhesive layer obtained from an optical adhesive composition according to an embodiment of the present invention.

  The touch panel type input / output device 100 according to the present embodiment includes a liquid crystal display device (LCD) 10, a touch panel unit 20, and an adhesive layer 30 provided between the LCD 10 and the touch panel unit 20. The adhesive layer 30 bonds the LCD 10 and the touch panel unit 20 together. Examples of the touch panel type input / output device 100 include a capacitance type touch panel type input / output device.

  For example, the adhesive layer 30 may be formed by applying the optical adhesive composition according to the present embodiment to the surface of a separator (not shown), and if necessary, applying light ( For example, the pressure-sensitive adhesive sheet obtained by irradiating with ultraviolet rays is peeled off from the separator and placed between the LCD 10 and the touch panel 20.

  Here, the oxygen is blocked by irradiating light with the composition layer sandwiched between the separator having the composition layer formed on the surface and the adherend, or by applying nitrogen to the entire coating machine. This can be achieved by performing light irradiation in a purged state.

  Alternatively, for example, the adhesive layer 30 is formed by applying a coating liquid containing the optical adhesive composition and the photopolymerization initiator (PI) according to the present embodiment to the surface of a separator (not shown). A layer is formed, and if necessary, the pressure-sensitive adhesive sheet is formed by irradiating the coating liquid layer with light (for example, ultraviolet rays) in a state where oxygen is blocked, and the pressure-sensitive adhesive sheet is peeled off from the separator. It may be installed between the touch panel 20.

  As shown in FIG. 1, the LCD 10 is configured by laminating a polarizing plate 11, an adhesive layer 12, a liquid crystal panel 13, an adhesive layer 14, and a polarizing plate 15 in this order. The adhesive layer 12 bonds the polarizing plate 11 and the liquid crystal panel 13, and the adhesive layer 14 bonds the liquid crystal panel 13 and the polarizing plate 15.

  As shown in FIG. 1, the touch panel unit 20 includes a scattering prevention film 16, an adhesive layer 17, an ITO layer 18, and a glass panel 19 that are laminated in this order. The adhesive layer 17 adheres the scattering prevention film 16 and the ITO layer 18.

  As with the adhesive layer 30, the adhesive layers 12, 14, and 17 may be manufactured using the optical adhesive composition according to the present embodiment.

1.6.2. Image Display Device An example in which the optical adhesive composition according to this embodiment is used for bonding members constituting the image display device will be described with reference to FIGS. 2 and 3.

  FIG. 2 is a schematic view showing a member configuration of an image display device (LCD) including an adhesive layer obtained from the optical adhesive composition according to one embodiment of the present invention. The image display device 200 shown in FIG. 2 can be manufactured, for example, by the steps shown in FIGS. 3 (a), 3 (b), and 3 (c).

  As shown in FIGS. 3 (a), 3 (b) and 3 (c), a liquid containing an optical adhesive composition and a photopolymerization initiator (PI) according to this embodiment is applied to an adherend ( An adhesive layer is formed between the LCD 110 and the cover lens / ITO layer 32 by forming a layer by filling between the LCD 110) and the cover lens / ITO layer 32, and irradiating the layer with light (for example, ultraviolet rays). 130 may be formed.

  More specifically, first, a dam layer 34 is formed on one surface of the adherend (LCD 110) shown in FIG. 3A so as to surround the side surface of the LCD 110 as shown in FIG. Form. Next, as shown in FIG. 3C, the filling liquid 36 containing the optical adhesive composition and the photopolymerization initiator (PI) according to this embodiment on the LCD 110 and inside the dam layer 34. Is dropped or patterned by a method such as patterning into a predetermined shape. Next, after the cover glass / ITO layer 32 is pressure-bonded onto the filling liquid 36, the filling liquid 36 is irradiated with light (for example, ultraviolet rays) in a state where oxygen is blocked, whereby the LCD 110, the cover glass / ITO layer 32, and the like. An adhesive layer for adhering is formed.

  The above 1.6.1. The photopolymerization initiator (PI) blended in the coating liquid (or the filling liquid) described in the column has a function as a reaction initiator when forming a pressure-sensitive adhesive sheet using the adhesive composition.

1.6.3. Method of Using Optical Adhesive Composition That is, the method of using the optical adhesive composition according to one embodiment of the present invention includes a photopolymerization initiator (PI) added to the optical adhesive composition according to the present embodiment. Adding. The photopolymerization initiator (PI) in the coating liquid (or filling liquid) according to this embodiment is preferably 0.1 parts by mass or more and 5 parts by mass or less with respect to 100 parts by mass of the adhesive composition. More preferably, it is 0.1 parts by mass or more and 3 parts by mass or less. The photopolymerization initiator (PI) is preferably, for example, an ultraviolet polymerization initiator that initiates polymerization by ultraviolet rays.

  Examples of the photopolymerization initiator (PI) include 2,2-dimethoxy-1,2-diphenylethane-1-one, 1-hydroxy-cyclohexyl-phenylketone, 2-hydroxy-1-1-1 {4- [4 -(2-hydroxy-2-methyl-propionyl) -benzyl] phenyl} -2-methyl-propan-1-one, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, 1- [4 -(2-Hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propan-1-one, 2-methyl-1 [4- (methylthio) phenyl] -2-morpholinopropane-1- ON, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1,6-trimethylbenzoyldiphenylphosphine oxide, benzoin methyl Ether, benzoin ethyl ether, benzoin propyl ether, benzoin isopropyl ether, benzoin isobutyl ether, 2,2-dimethoxy-1,2-diphenylethane-1-one, anisole methyl ether, 2,2-diethoxyacetophenone, 2,2 -Dimethoxy-2-phenylacetophenone, 1-hydroxycyclohexyl phenyl ketone, 4-phenoxydichloroacetophenone, 4-t-butyl-dichloroacetophenone, 2-naphthalenesulfonyl chloride, 1-phenyl-1,1-propanedione-2- ( o-Ethoxycarbonyl) -oxime, benzoin, benzyl, benzophenone, benzoylbenzoic acid, 3,3′-dimethyl-4-methoxybenzophenone, polyvinylbenzophenone, α-hydride Roxycyclohexyl phenyl ketone, benzyldimethyl ketal, thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, 2,4-dichlorothioxanthone, 2,4-diethylthioxanthone, 2,4-diisopropyl Thioxanthone, dodecylthioxanthone, 4- (2-hydroxyethoxy) phenyl (2-hydroxy-2-propyl) ketone, α-hydroxy-α, α'-dimethylacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2- Examples thereof include hydroxy-2-cyclohexylacetophenone, benzyl dimethyl ketal, halogenated ketone, acyl phosphine oxide, and acyl phosphonate. Such photopolymerization initiators (PI) can be used alone or in combination.

1.7. Effects The optical adhesive composition according to this embodiment includes a (meth) acrylic resin (A), a monomer mixture (m) containing N-vinylcarboxylic acid amide (mc), and (B) a crosslinking agent. As a result, the compatibility between the (meth) acrylic resin (A) and the monomer mixture (m) can be increased due to (mc) which is N-vinylcarboxylic acid amide. Excellent transparency.

  N-vinylcarboxylic acid amide (mc) has high hydrophilicity due to its molecular structure, and has an effect of imparting moisture and heat whitening resistance of the adhesive layer, and also has an alkyl group at the end of the side chain. Therefore, it is considered that the effect of increasing the compatibility between the (meth) acrylic resin (A) and the monomer mixture (m) is high.

  Therefore, when the optical adhesive composition according to this embodiment contains N-vinylcarboxylic acid amide (mc), when the monomer mixture (m) is polymerized by active energy rays, a (meth) acrylic type is used. Compatibility with the resin (A) can be maintained, and a transparent optical pressure-sensitive adhesive sheet can be obtained.

  Moreover, since N-vinylcarboxylic acid amide (mc) is hardly hydrolyzed due to the molecular structure, the transparency of the optical pressure-sensitive adhesive sheet obtained from the composition can be maintained for a long time.

  Therefore, since the adhesive layer formed using the optical adhesive composition according to the present embodiment is excellent in transparency and moisture and heat whitening resistance, for example, a touch panel type input / output device including a metal such as ITO Or it can use suitably for bonding of the member which comprises an image display apparatus.

2. Pressure-sensitive adhesive sheet The pressure-sensitive adhesive sheet (optical pressure-sensitive adhesive sheet) according to this embodiment can be produced using, for example, the optical adhesive composition according to the above-described embodiment. The thickness of the pressure-sensitive adhesive sheet is usually from 10 μm to 500 μm, preferably from about 20 μm to 300 μm.

  More specifically, on the base material, the optical adhesive composition according to the above embodiment is applied by a gravure coater, a Mayer bar coater, an air knife coater, a roll coater, and the like. The adhesive sheet which concerns on can be produced.

  The pressure-sensitive adhesive sheet according to the present embodiment is excellent in transparency, moist heat whitening resistance and cutability by being formed using the optical adhesive composition according to the above-described embodiment. Therefore, the pressure-sensitive adhesive sheet according to the present embodiment can be suitably used for bonding optical members, and more specifically, preferably used for bonding members constituting a touch panel type input / output device or an image display device. be able to.

3. EXAMPLES Hereinafter, the present invention will be described based on the following examples, but the present invention is not limited to the examples.

3.1. Examples 1 to 14 and Comparative Examples 1 to 5 (Preparation of optical adhesive composition)
Optical adhesive compositions for Examples 1 to 14 and Comparative Examples 1 to 5 were prepared with the formulations shown in Table 1 below. More specifically, a monomer mixture (m1) heated to 60 ° C. in a reactor equipped with a stirrer, a reflux condenser, a thermometer, and a nitrogen introduction tube, and 100% of the monomer mixture (m1) In the case of mass%, 0.005 mass% to 2.0 mass% of normal dodecyl mercaptan was added and purged with nitrogen, and a small amount of 2,2′-azobis (4-methoxy-2,4-dimethyl) valeronitrile was added. By adding, it heats up to 120 degreeC or more and 140 degrees C or less, and obtains a partial copolymer (P). When the exotherm reached a peak, the monomer mixture (m2) was added to obtain compositions (D) of Examples 1 to 14 and Comparative Examples 1 to 5. Furthermore, 0.5 parts by mass of trimethylolpropane triacrylate as a crosslinking agent (B) and 2-hydroxy-2-methyl-1-phenyl as a photopolymerization initiator (PI) with respect to 100 parts by mass of the composition (D). -0.3-1 part by mass of propan-1-one (Darocur 1173: Ciba Geigy Co., Ltd.) was added to prepare optical adhesive compositions for Examples 1 to 14 and Comparative Examples 1 to 5.

  In Table 1, the blending amounts of the (a2) component, the (b2) component, the (c2) component, and the (d2) component included in the (m2) component were set to 100% by mass of the (m1) component. In the case. In Table 1, the ratio of (a1) component, (b1) component, (c1) component, (d1) in component (m1), (a2) component, (b2) component in (m2) component, ( The ratios of the component c2) and the component (d2) are both expressed in mass%.

  In Table 1, when the monomer mixture (m1) is 100% by mass, the total of the component (a1), the component (b1), the component (c1) and the component (d1) is 100% by mass. Moreover, in Table 1, when a monomer mixture (m2) is 100 mass%, the sum total of (a2) component, (b2) component, (c2) component, and (d2) component is 100 mass%. Further, in Table 1, the content of the component (ma), the content of the component (mb), and the content of the component (mc) are the contents when the monomer mixture (m) is 100% by mass. It is.

3.2. Production Example 1 (Manufacture of adhesive sheet)
After the optical adhesive compositions of Examples 1 to 14 and Comparative Examples 1 to 5 were applied to the surface of a release-treated polyester film (hereinafter referred to as “separator”), oxygen in the air was blocked with another separator, and black light Was irradiated for 180 seconds to obtain a separator sand for each adhesive. Also, one of the separators was peeled off and bonded to a PET substrate having a thickness of 100 μm to obtain various pressure-sensitive adhesive sheets.

3.3. Evaluation Method About the optical adhesive compositions of Examples 1 to 14 and Comparative Examples 1 to 5, as shown in Table 1 below, the content ratio of (meth) acrylic resin (A) and (meth) acrylic resin ( The composition ratio of each monomer in the monomer component for preparing A), and the content ratio and composition ratio of the monomer mixture (m) were calculated by the methods described later. Moreover, the syrup initial turbidity of each adhesive composition and the turbidity after storage were measured.

  Further, the weight average molecular weight (Mw) and dispersion (Mw / Mn) of the (meth) acrylic resin (A) contained in the optical adhesive compositions of Examples 1 to 14 and Comparative Examples 1 to 5 were determined by the following method. Measured with

  Further, for the pressure-sensitive adhesive sheet of Production Example 1 obtained using the optical adhesive compositions of Examples 1 to 14 and Comparative Examples 1 to 5, the initial haze of the sheet, the haze after aging of the sheet, and the wet heat test of the sheet The haze was evaluated.

3.3.1. Composition ratio of the monomer mixture (m) in the adhesive composition Using a gas chromatographic apparatus (model name GC-1700 (manufactured by Shimadzu Corporation)) as a measuring instrument, according to the method described in the above embodiment, Examples The content ratio (composition ratio) of the monomer mixture (m) in the optical adhesive compositions of 1 to 14 and Comparative Examples 1 to 5 was calculated.

  More specifically, 0.1 g of each adhesive composition was dissolved in about 10 g of dichloromethane, and 1 drop of isopentyl benzoate was added as an internal standard to prepare a measurement sample. The content ratio (composition ratio) of the (ma) component, the (mb) component, and the (mc) component in each monomer mixture (m) was measured using a gas chromatography apparatus equipped with the following column.

3.3.2. Content of (meth) acrylic resin (A) in adhesive composition Each of the optical adhesive compositions of Examples 1 to 14 and Comparative Examples 1 to 5 was weighed into a metal container and dried at 200 ° C. for 3 hours. The content of the (meth) acrylic resin (A) in each adhesive composition was calculated by measuring the mass of the component ((meth) acrylic resin (A)) that did not volatilize with a precision balance. . Moreover, the content of the monomer mixture (m) in each composition was calculated by subtracting the mass of the component that did not volatilize from the mass of each composition weighed.

  The (meth) acrylic resin (A) is a copolymer derived from part of the (m1) component and the (m2) component. More specifically, the (meth) acrylic resin (A) (component (A)) is a monomer mixture (m) (component (m)) from the total amount of the components (m1) and (m2) used. Is formed from a monomer component obtained by subtracting.

  In Table 1, the content ratio of the component (A) and the content ratio of the component (m) in each composition, the ratio of the structural unit derived from the component (A1) in the component (A), and the component (A2) The proportion of structural units derived from (A3), the proportion of structural units derived from component (A3), the proportion of structural units derived from component (A4), and the content of component (ma) in component (m), ( The content ratio of the mb) component, the content ratio of the (mc) component, and the content ratio of the (md) component are values calculated by the following methods, respectively.

  (1) First, by gas chromatography analysis on the composition, the content ratio of the component (ma), the content ratio of the component (mb), and the content ratio of the component (mc) in the composition (further, the component (md)) Is included, the (md) component content ratio) is measured.

  (2) Next, when the monomer component used in producing the component (A) is (M), the content ratio of the component (A1) in the monomer component (M), (A2) The content ratio of the component and the content ratio of the component (A3) (further, when the component (A) includes the component (A4), the content ratio of the component (A4) in the monomer component (M)) are calculated.

  The proportion of the component (A1), the component (A2), the component (A3) and the component (A4) is the content ratio of the component (a1) in the component (m1) used when producing the composition, (b1) Content ratio of component, content ratio of component (c1) and content ratio of component (d1), content ratio of component (a2) in component (m2) used when producing the composition, component content of (b2) Content ratio, content ratio of component (c2) and content ratio of component (d2), and content ratio of component (ma) in component (m) measured in (1) above, content of component (mb) From the ratio, the content ratio of the (mc) component (in addition, when the (md) component is included, the content ratio of the (md) component in the (m) component) can be obtained by calculation.

  In this case, the total amount (mass of the composition) of the (m1) component and the (m2) component is defined as CON (that is, CON is the mass of the entire composition). In addition, the content ratio of the (ma) component, the content ratio of the (mb) component, and the content ratio of the (mc) component in the composition are respectively a, b, c (mass%) (further, the (md) component is included) In this case, the content ratio of the component (md) is d (mass%). That is, the content (mass%) of the component (m) in the composition is represented by a + b + c + d (mass%).

  In addition, the content ratio of the component (A1) in the monomer component (M) used when the component (A) is produced (the ratio of the structural unit derived from the component (A1) in the component (A)), (A2) Content ratio of component (ratio of structural unit derived from component (A2) in component (A)), content ratio of content ratio of component (A3) (ratio of structural unit derived from component (A3) in component (A)), And the content ratios of the component ratios (A4) (ratio of structural units derived from the component (A4) in the component (A)) are ax, bx, cx, and dx, respectively.

  Further, the content of the component (a1), the content of the component (b1), the content of the component (c1) and the content of the component (d1) in the component (m1) are respectively a1, b1, c1, d1 (whichever (M2) component (a2) component content, (b2) component content, (c2) component content and (d2) component content a2, b2, c2, d2 (both are masses).

  In this case, in the monomer component (M) used to produce the component (A), the proportion of the component (A1), the proportion of the component (A2), the proportion of the component (A3) and the component (A4) are Respectively, they are represented by the following formulas 6 to 9. In addition, in the component (m), the content ratio of the component (ma), the content ratio of the component (mb), the content ratio of the component (mc), and the ratio (% by mass) of the component (md) are as follows. Represented by equations 10-13.

Content ratio X (mass%) of component (A) in the composition = 100− (a + b + c + d) (Formula 1)
Content ratio α (mass%) of ((a1) component + (a2) component) in the composition = (a1 + a2) / CON (Formula 2)
Content ratio β (mass%) of ((b1) component + (b2) component) in the composition = (b1 + b2) / CON (formula 3)
Content ratio γ (mass%) of ((c1) component + (c2) component) in the composition = (c1 + c2) / CON (Formula 4)
Content ratio δ (mass%) of ((d1) component + (d2) component) in the composition = (d1 + d2) / CON (formula 5)

Ratio (a) (% by mass) of constituent unit derived from component (A1) in component (A1) = (α−a) / X (Formula 6)
Ratio (b) (mass%) of constituent units derived from component (A2) in component (A) = (β−b) / X (Formula 7)
Ratio of structural unit derived from component (A3) in component (A) cx (mass%) = (γ−c) / X (Formula 8)
Ratio of structural unit derived from component (A4) in component (A) dx (mass%) = (δ−d) / X (Formula 9)

Here, the content ratio of the (ma) component, (mb) component, (mc) component, and (md) component in the (m) component is determined as follows.
Content ratio (mass%) of component (ma) in component (m) = a / (a + b + c + d) (Formula 10)
Content ratio (mass%) of component (mb) in component (m) = b / (a + b + c + d) (Formula 11)
(M) Content ratio (mass%) of component (mc) in component = c / (a + b + c + d) (Formula 12)
(M) Content ratio (mass%) of component (md) in component = d / (a + b + c + d) (Formula 13)

  In addition, the said calculation method is an example to the last, Comprising: For example, it is also possible to calculate the ratio of each component which comprises a composition by various instrumental analysis, such as GC / MS and NMR.

3.3.3. Weight average molecular weight (Mw) and dispersion (Mw / Mn) of (meth) acrylic resin (A)
The weight of the (meth) acrylic resin (A) contained in the optical adhesive compositions of Examples 1 to 14 and Comparative Examples 1 to 5 using model name HLC-8120GPC (manufactured by Tosoh Corporation) as a measuring instrument. Average molecular weight (Mw) and dispersion (Mw / Mn) were measured.

3.3.4. Initial turbidity The initial turbidity of the optical adhesive compositions of Examples 1 to 14 and Comparative Examples 1 to 5 was measured with COH400 manufactured by Nippon Denshoku Co., Ltd. The initial turbidity is an indicator of the transparency of the adhesive composition. The initial turbidity is preferably 5 or less.

3.3.5. Turbidity after storage The turbidity after storing the optical adhesive compositions of Examples 1 to 14 and Comparative Examples 1 to 5 at 60 ° C. for 15 days was measured with COH400 manufactured by Nippon Denshoku Co., Ltd. The turbidity after storage is an index indicating whether or not the transparency (turbidity) of the adhesive composition tends to increase. The turbidity after storage is preferably 5 or less.

3.3.6. Initial haze of sheet Using the separator sand of each adhesive obtained in Production Example 1 above, only the adhesive layer was bonded to a glass substrate and bonded using a haze meter HM-150 (Murakami Color Research Laboratory). The initial haze of only the agent layer was measured. The initial haze of only the adhesive layer is preferably 1.0 or less.

3.3.7. Haze after sheet aging After the separator sand of each adhesive obtained in the above Production Example 1 was stored at 40 ° C. for 1 month, only the adhesive layer was bonded to a glass substrate, and a haze meter HM-150 (Murakami Color Research Laboratory) was used. The post-aging haze of only the adhesive layer was measured using a laboratory. The haze after aging of only the adhesive layer is preferably 1.0 or less.

3.3.8. Change value of haze after wet heat test of sheet 3.2. The separator of the pressure-sensitive adhesive sheet prepared in Production Example 1 was peeled off and attached to a glass substrate as a measurement material, and the haze was measured with a haze meter (model name “HM-150”, manufactured by Murakami Color Research Laboratory). (Initial haze). Next, the sample was added for 100 hours under the condition of 65 ° C.-95% RH, and then the haze was measured 10 minutes after being transferred to the condition of 23 ° C.-50% RH (haze after wet heat test). The initial haze-haze value after the wet heat test (change in haze value after the wet heat test) is an index of resistance to moist heat whitening, and is preferably 0.5 or less.

3.3.9. ITO corrosive pressure-sensitive adhesive sheet obtained by using the compositions of Examples 1 to 14 and Comparative Examples 1 to 5 obtained in Production Example 1 on an ITO-deposited PET film cut to 10 mm x 100 mm to 10 mm x 60 mm Cut and pasted and autoclaved at 50 ° C. × 5 atm for 20 minutes. Next, after standing at room temperature for 1 hour, placing it in an environment of 60 ° C. and 90% RH for 500 hours, standing at 23 ° C. and humidity of 65% RH for 1 hour, then the resistance of the ITO deposited film The value was measured and compared with the resistance value before the test measured in advance, and the rate of change of the resistance value with respect to the resistance value before the test was determined.

  When the change rate of the resistance value with respect to the resistance value before the test is 115% or more, it is determined that there is ITO corrosivity, and when the change rate of the resistance value with respect to the resistance value before the test is less than 115%, the ITO It was judged that there was no corrosiveness. Note that a tester (manufactured by Sanwa Denki Keiki Co., Ltd., Digital Multimeter PC510) was used for measuring the resistance value.

In addition, the abbreviation in Table 1 has the following meaning.
AA: acrylic acid AM: acrylamide BA: n-butyl acrylate DMAA: dimethyl acrylamide 2-EHA: 2-ethylhexyl acrylate 2-HEA: 2-hydroxyethyl acrylate 4-HBA: 4-hydroxybutyl acrylate LA: lauryl acrylate NVA: N -Vinylcarboxylic acid amide NVMA: N-vinyl-N-methylacetamide

  From the results of Table 1, according to the adhesive compositions of Examples 1 to 14, the (meth) acrylic resin (A), the monomer mixture (m) containing the component (mc), and the crosslinking agent ( B), the adhesive layer is excellent in transparency, and it can be understood that the adhesive layer formed using the adhesive composition is excellent in transparency and resistance to moist heat whitening.

  Also, the adhesive compositions of Examples 1 to 14 were applied to the surface of the separator, irradiated with light to form an adhesive layer having a thickness of 150 μm, and this adhesive layer was cut using a punching machine. However, it was confirmed that it was excellent in cutability because it could be cut without causing stringing.

  Further, the adhesive compositions of Examples 1 to 12 and 14 had ITO corrosiveness. On the other hand, the adhesive composition of Example 13 was inferior in ITO corrosivity. The reason is that, in the adhesive composition of Example 13, the monomer mixture (m1) contains 1.0% by mass of acrylic acid, so that the acid value of the composition exceeds 1.0 or more. It is assumed that there is.

  On the other hand, since the adhesive compositions of Comparative Examples 1 to 4 do not contain the N-vinylcarboxylic acid amide (mc), the adhesive composition has low transparency (has turbidity) and the adhesive composition. It can be understood that the adhesive layer formed by using an object is also inferior in transparency and wet heat whitening resistance.

  The adhesive composition of Comparative Example 5 is a monomer mixture containing no (meth) acrylic resin (A) having no hydroxyl group and (meth) acrylic monomer (mb) having a hydroxyl group. By including (m), water aggregation is likely to occur in the system, so that the adhesive layer formed using the adhesive composition is presumed to be inferior in transparency and resistance to moist heat whitening.

10,110 Liquid crystal display (LCD)
DESCRIPTION OF SYMBOLS 11,15 Polarizing plate 12,14,17 Adhesive layer 13 Liquid crystal panel 16 Anti-scattering film 18 ITO layer 19 Glass panel 20 Touch panel part 30,130 Adhesive layer 32 Cover lens / ITO layer 34 Dam layer 36 Filling liquid 100 Touch panel type I / O device 200 Image display device.

Claims (9)

(Meth) acrylic resin (A),
Monomer mixture (m);
A crosslinking agent (B);
Including
When the monomer mixture (m) is 100% by mass of the monomer mixture (m),
(Ma) 45% by mass or more and 94.9% by mass or less of a (meth) acrylic monomer having an alkyl group having 1 to 18 carbon atoms;
(Mb) a (meth) acrylic monomer having a hydroxyl group of 5% by mass to 45% by mass;
(Mc) N-vinylcarboxylic acid amide 0.1% by mass to 10% by mass;
Including
The (meth) acrylic resin (A) is
(A1) a (meth) acrylic monomer (A1) having an alkyl group having 1 to 18 carbon atoms;
(A2) a (meth) acrylic monomer (A2) having a hydroxyl group;
An optical adhesive composition, which is a copolymer of monomer components containing   The optical adhesive composition according to claim 1, wherein the (meth) acrylic resin (A) has a weight average molecular weight of 10,000 or more and 800,000 or less. The optical adhesive composition according to claim 1 or 2, wherein the N-vinylcarboxylic acid amide (mc) is represented by the following formula (1).

(1)
(Wherein R ¹ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and R ² represents an alkyl group having 1 to 4 carbon atoms.)   The blending amount of the monomer mixture (m) is 10 parts by mass or more and 1,000 parts by mass or less with respect to 100 parts by mass of the (meth) acrylic resin (A). 2. An optical adhesive composition according to item 1.   The optical adhesive composition according to any one of claims 1 to 4, wherein each of the acid values of the (meth) acrylic resin (A) and the monomer mixture (m) is 1.0 or less. object. A method for producing the optical adhesive composition according to any one of claims 1 to 5,
(Meth) acrylic monomer (a1) having an alkyl group having 1 to 18 carbon atoms, and (meth) acrylic monomer (b1) having a hydroxyl group in a system substantially free from a solvent, A step of polymerizing a part of the monomer mixture (m1) containing a partial copolymer (P);
(Meth) acrylic monomer (a2) having an alkyl group having 1 to 18 carbon atoms, (meth) acrylic monomer (b2) having a hydroxyl group, N-vinylcarboxylic acid amide (c2), A step of adding a monomer mixture (m2) containing: to the partial polymer (P);
The manufacturing method of the adhesive composition for optics containing this.   A method for using an optical adhesive composition, comprising a step of adding a photopolymerization initiator (PI) to the optical adhesive composition according to any one of claims 1 to 5.   An optical pressure-sensitive adhesive sheet obtained by applying the optical adhesive composition according to claim 1 to the surface of a separator and irradiating with light.   The optical pressure-sensitive adhesive sheet according to claim 8, which is used for bonding members constituting a touch panel type input / output device or an image display device.

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