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KR-102961417-B1 - Curable adhesive composition and polarizing plate

KR102961417B1KR 102961417 B1KR102961417 B1KR 102961417B1KR-102961417-B1

Abstract

[Problem] The objective of the present invention is to provide a polarizing plate having good durability, comprising a polarizer, an adhesive layer, and a thermoplastic resin film in that order. [Solution] A polarizing plate is provided comprising a polarizer, an adhesive layer, and a thermoplastic resin film in that order, wherein the adhesive layer is a cured layer of a curable adhesive composition comprising a maleic anhydride modified compound (A), a (meth)acrylate compound (B), and a photopolymerization initiator (C). The curable adhesive composition may further comprise a petroleum resin (D).

Inventors

  • 야스이 미오
  • 이와타 도모
  • 사카우에 치에

Assignees

  • 스미또모 가가꾸 가부시키가이샤

Dates

Publication Date
20260507
Application Date
20201117
Priority Date
20191122

Claims (14)

  1. A polarizing plate comprising a polarizer, an adhesive layer, and a thermoplastic resin film in this order, The adhesive layer is a cured layer of a curable adhesive composition comprising a maleic anhydride modified compound (A), a (meth)acrylate compound (B), and a photopolymerization initiator (C), and A polarizing plate wherein the above (meth)acrylate compound (B) comprises a two-function (meth)acrylate compound (B-2), and the above two-function (meth)acrylate compound (B-2) comprises a compound represented by the following formula. (In the formula, R1 and R2 each independently represent a hydrogen atom or a methyl group, X represents ethylene oxide ( -C2H4O- ) or propylene oxide ( -C3H6O- ), n represents an integer from 1 to 20 , and m represents an integer from 1 to 20.)
  2. A polarizing plate according to claim 1, wherein the (meth)acrylate compound (B) further comprises a single-function (meth)acrylate compound (B-1).
  3. A polarizing plate according to paragraph 2, wherein the content of the single-function (meth)acrylate compound (B-1) in the curable adhesive composition is 60 mass% or more of the (meth)acrylate compound (B) at least 100 mass%.
  4. A polarizing plate according to claim 3, wherein the content of the single-function (meth)acrylate compound (B-1) in the curable adhesive composition is 99 mass% or less of the 100 mass% of the (meth)acrylate compound (B).
  5. A polarizing plate according to any one of claims 2 to 4, wherein the single-function (meth)acrylate compound (B-1) comprises at least one compound selected from the group consisting of alicyclic alkyl (meth)acrylate compounds and aromatic (meth)acrylate compounds.
  6. A polarizing plate according to any one of claims 1 to 4, wherein the curable adhesive composition further comprises petroleum resin (D).
  7. A polarizing plate according to any one of claims 1 to 4, wherein the maleic anhydride modified compound (A) comprises a maleic anhydride modified polymer (A-1).
  8. A polarizing plate according to any one of claims 1 to 4, wherein the cured film having a thickness of 10 μm made of the curable adhesive composition has a moisture permeability of 400 g/( m² ·24hr) or less at a temperature of 40℃ and a relative humidity of 90%.
  9. A polarizing plate according to any one of claims 1 to 4, wherein the laminate of a (meth)acrylic resin film with a thickness of 60 μm and a curable film with a thickness of 10 μm composed of the curable adhesive composition has a moisture permeability of 55 g/( m² ·24hr) or less at a temperature of 40℃ and a relative humidity of 90%.
  10. In any one of claims 1 to 4, the thermoplastic resin film is a (meth)acrylic resin film, a polarizing plate.
  11. A polarizing plate according to any one of claims 1 to 4, wherein the thickness of the adhesive layer is 2 μm or more and 50 μm or less.
  12. It comprises a maleic anhydride modified compound (A), a (meth)acrylate compound (B), a photopolymerization initiator (C), and a petroleum resin (D), and A curable adhesive composition wherein the above (meth)acrylate compound (B) comprises a monofunctional (meth)acrylate compound (B-1) and a dual-functional (meth)acrylate compound (B-2), and the dual-functional (meth)acrylate compound (B-2) comprises a compound represented by the following formula. (In the formula, R1 and R2 each independently represent a hydrogen atom or a methyl group, X represents ethylene oxide ( -C2H4O- ) or propylene oxide ( -C3H6O- ), n represents an integer from 1 to 20 , and m represents an integer from 1 to 20.)
  13. In claim 12, the curable adhesive composition having a thickness of 10 μm, the curable film formed from the above curable adhesive composition, has a moisture permeability of 400 g/( m² ·24hr) or less at a temperature of 40℃ and a relative humidity of 90%.
  14. A polarizing plate comprising a polarizer, an adhesive layer, and a thermoplastic resin film in this order, The above adhesive layer is a polarizing plate that is a cured layer of the curable adhesive composition described in claim 12 or 13.

Description

Curable adhesive composition and polarizing plate The present invention relates to a curable adhesive composition and a polarizing plate. Polarizers, which are widely used in image display devices such as liquid crystal displays and organic EL displays, typically have a configuration in which a thermoplastic resin film, such as a protective film, is bonded to one or both sides of a polarizer. An adhesive is typically used to bond the polarizer and the thermoplastic resin film. As such adhesives, active energy beam curable adhesives or water-based adhesives are known [e.g., Japanese Patent Publication No. 2009-008860 (Patent Document 1)]. FIG. 1 is a schematic cross-sectional view illustrating an example of the layer configuration of a polarizing plate according to the present invention. FIG. 2 is a schematic cross-sectional view illustrating another example of the layer configuration of a polarizer according to the present invention. Curable adhesive composition The curable adhesive composition according to the present invention (hereinafter also referred to as the "adhesive composition") is suitable for bonding thermoplastic resin films and, for example, can be used for bonding a thermoplastic resin film with another thermoplastic resin film (or layer). One example of application of the adhesive composition according to the present invention is for polarizers, that is, it can be used to manufacture polarizers. More specifically, the adhesive composition according to the present invention is useful as an adhesive composition used for bonding a polarizer and a thermoplastic resin film. In this specification, the term "polarizing plate" refers to a laminated optical film comprising a polarizer and a thermoplastic resin film laminated on one or both sides thereof. In the polarizing plate, the polarizer and the thermoplastic resin film are laminated through an adhesive layer. The adhesive layer is a layer formed from an adhesive composition, and more specifically, a cured layer of the adhesive composition. The polarizing plate may include a polarizer and a film or layer other than the thermoplastic resin film. The adhesive composition above is a curable adhesive composition comprising a maleic anhydride modified compound (A), a (meth)acrylate compound (B), and a photopolymerization initiator (C). The adhesive composition may also include components other than the maleic anhydride modified compound (A), the (meth)acrylate compound (B), and the photopolymerization initiator (C). Meanwhile, the compounds exemplified as each component included or that may be included in the adhesive composition in this specification may be used alone or in combination of multiple types unless specifically mentioned. [1] Maleic anhydride modified compound (A) The maleic anhydride modified compound (A) is a compound that contains a maleic anhydride structure within its molecule. The adhesive composition may contain one type of maleic anhydride modified compound (A), or may contain two or more types of maleic anhydride modified compounds (A). Maleic anhydride modified compound (A) may include a maleic anhydride modified polymer (A-1). The maleic anhydride modified polymer (A-1) is a polymer modified by introducing a maleic anhydride structure as a side chain of the polymer. The adhesive composition may contain one type of maleic anhydride modified polymer (A-1) or two or more types of maleic anhydride modified polymers (A-1). The above maleic anhydride structure refers to the following structure. (* indicates bond loss to the main chain.) In the maleic anhydride modified polymer (A-1), the polymer modified by maleic anhydride may be a diene polymer, a polyolefin polymer, a (meth)acrylic polymer, a polyester polymer, a polystyrene polymer, a polyether polymer, etc. These polymers may be homopolymers composed of one type of monomer, or copolymers composed of two or more types of monomers. In this specification, "(meth)acrylic" refers to at least one selected from the group consisting of acrylic and methacrylic. The same applies to notations such as "(meth)acryloyl" and "(meth)acrylate". In order to prepare an adhesive composition that is solvent-free and has good adhesive ability, it is preferable that the maleic anhydride modified polymer (A-1) be in a liquid state. A liquid state means that it exhibits fluidity at a temperature of 25°C. The viscosity of the liquid maleic anhydride modified polymer (A-1) at 25°C is preferably 10 Pa·sec or more and 10,000 Pa·sec or less, more preferably 15 Pa·sec or more and 7,000 Pa·sec or less, even more preferably 15 Pa·sec or more and 300 Pa·sec or less, and particularly preferably 15 Pa·sec or more and 100 Pa·sec or less, from the perspective of obtaining an adhesive composition with good coating properties. A preferred example of a liquid maleic anhydride modified polymer (A-1) is, for instance, maleic anhydride modified polybutadiene. Each of these polymers may be a homopolymer or a copolymer, an