Search

KR-20260064532-A - COMPOSITION FOR FORMING HARD COAT LAYER, HARD COAT LAYER, POLARIZING PLATE AND IMAGE DISPLAY DEVICE

KR20260064532AKR 20260064532 AKR20260064532 AKR 20260064532AKR-20260064532-A

Abstract

(Problem) To provide a composition for forming a hard coat layer capable of suppressing the occurrence of red discoloration in a polarizer. (Solution) A composition for forming a hard coat layer comprising a monomer component (a), a radical polymerization initiator, and a rosin compound having an acid value of 100 mg KOH/g or more and 500 mg KOH/g or less, wherein the monomer component (a) contains a monomer (a-1) having two or more (meth)acryloyl groups.

Inventors

  • 후쿠다, 켄이치

Assignees

  • 수미토모 케미칼 컴퍼니 리미티드

Dates

Publication Date
20260507
Application Date
20251017
Priority Date
20241031

Claims (19)

  1. A monomer component (a), a radical polymerization initiator, and a rosin compound having an acid value of 100 mgKOH/g or more and 500 mgKOH/g or less, comprising The above monomer component (a) is a composition for forming a hard coat layer, comprising a monomer (a-1) having two or more (meth)acryloyl groups.
  2. In paragraph 1, The above rosin compound is a composition for forming a hard coat layer, selected from the group consisting of rosin, hydrogenated rosin, acid-modified rosin, and hydrogenated acid-modified rosin.
  3. In paragraph 1, A composition for forming a hard coat layer, wherein the ratio of the monomer (a-1) to the monomer component (a) is 50 mass% or more based on the total amount of the monomer component (a).
  4. In paragraph 1, A composition for forming a hard coat layer, wherein the content of the above rosin compound is 1 part by mass or more and 10 parts by mass or less per 100 parts by mass of the above monomer component (a).
  5. In paragraph 1, A composition for forming a hard coat layer, wherein the content of the radical polymerization initiator is 0.1 parts by mass or more and 15 parts by mass or less per 100 parts by mass of the monomer component (a).
  6. In paragraph 1, The above monomer (a-1) contains a monomer (a-1-1) having three or more (meth)acryloyl groups, and A composition for forming a hard coat layer, wherein the ratio of the monomer (a-1-1) to the monomer (a-1) is 50 mass% or more.
  7. In paragraph 1, A composition for forming a hard coat layer, wherein the content of the monomer having a hydroxyl group is 40 mass% or less based on the total amount of the monomer component (a).
  8. In paragraph 1, A composition for forming a hard coat layer, for forming a hard coat layer that is laminated together with a polarizer to form a polarizing plate.
  9. In paragraph 8, The above polarizer is a composition for forming a hard coat layer comprising a polyvinyl alcohol-based resin layer in which iodine is adsorbed and oriented.
  10. A hard coat layer comprising a cured product of a composition for forming a hard coat layer as described in any one of claims 1 to 9.
  11. A polymer (A) having a monomer unit (A-1) derived from a monomer (a-1) having two or more (meth)acryloyl groups, and A hard coat layer comprising a rosin compound having an acid value of 100 mg KOH/g or more and 500 mg KOH/g or less.
  12. In Paragraph 11, A hard coat layer in which the ratio of the monomer unit (A-1) to the polymer (A) is 50 mass% or more.
  13. In Paragraph 11, The above rosin compound is a hard coat layer selected from the group consisting of rosin, hydrogenated rosin, acid-modified rosin, and hydrogenated acid-modified rosin.
  14. In Paragraph 11, A hard coat layer in which the content of the above rosin compound is 1 part by mass or more and 10 parts by mass or less per 100 parts by mass of the above polymer (A).
  15. In Paragraph 11, The above monomer unit (A-1) contains a monomer unit (A-1-1) derived from a monomer (a-1-1) having three or more (meth)acryloyl groups, and A hard coat layer in which the ratio of the monomer unit (A-1-1) to the monomer unit (A-1) is 50 mass% or more.
  16. Polarizer, and A polarizing plate having a hard coat layer as described in Clause 10.
  17. Polarizer, and A polarizing plate having a hard coat layer as described in Clause 11.
  18. An image display device having a polarizing plate and an image display panel as described in paragraph 16.
  19. An image display device having a polarizing plate and an image display panel as described in paragraph 17.

Description

Composition for forming a hard coat layer, hard coat layer, polarizing plate and image display device The present disclosure relates to a composition for forming a hard coat layer, a hard coat layer, a polarizing plate, and an image display device. As described in Patent Document 1, it is known that a phenomenon called reddening occurs when a polarizing plate is placed under a high-temperature environment. Reddening is a phenomenon in which the polarizing plate appears red when cross-Nicole is placed, as the transmittance on the long wavelength side of about 700 nm increases. Figure 1 is a schematic cross-sectional view showing an example of a polarizing plate. FIG. 2 is a schematic cross-sectional view showing an example of an image display device. Hereinafter, preferred embodiments of the present invention will be described in detail. Composition for forming a hard coat layer The composition for forming a hard coat layer according to the present embodiment is a curable composition comprising a monomer component (a), a radical polymerization initiator, and a rosin compound having an acid value of 100 mg KOH/g or more and 500 mg KOH/g or less. Monomer component (a) contains a monomer (a-1) having two or more (meth)acryloyl groups. According to the inventors' knowledge, ammonia gas entering from the outside comes into contact with the polarizer, causing reddening of the polarizer. Since the composition for forming a hard coat layer of the present embodiment includes a rosin compound having a predetermined acid value, an acidic group (e.g., a carboxyl group) derived from the rosin compound is present in the cured product. Therefore, according to the composition for forming a hard coat layer of the present embodiment, a hard coat layer having an acidic group (e.g., a carboxyl group) is formed, and the hard coat layer traps ammonia gas, thereby preventing the intrusion of ammonia gas into the polarizer and suppressing reddening of the polarizer. In addition, the composition for forming a hard coat layer according to the present embodiment employs a rosin compound as a component for introducing acidic groups. In the present embodiment, the moisture permeability of the hard coat layer is reduced by the use of a rosin compound. This is presumed to be because the flat molecular structure of the rosin compound tends to be oriented in the in-plane direction of the hard coat layer, thereby hindering the passage of water molecules in the vertical direction. Therefore, since the moisture permeability of a hard coat layer usually tends to improve (i.e., moisture resistance decreases) when acidic groups are introduced, the composition for forming a hard coat layer according to the present embodiment can form a hard coat layer that maintains low moisture permeability while introducing acidic groups. If the moisture permeability of the hard coat layer is low, it is possible to suppress the penetration of ammonia molecules along with water molecules into the polarizer, and red discoloration is also suppressed in this respect. In addition, since the composition for forming a hard coat layer of the present embodiment contains monomer (a-1) as a monomer component, the hardness of the cured product is increased, and a hard coat layer having sufficient hardness can be formed. For this reason, the hard coat layer formed by the composition for forming a hard coat layer of the present embodiment can be easily introduced into a polarizing plate by substitution with the hard coat layer of the existing polarizing plate, or by addition to the resin layer of the existing polarizing plate. The monomer component (a) may be a compound having, for example, a (meth)acryloyl group or a polymerizable group capable of polymerizing with a (meth)acryloyl group (for example, an ethylenically unsaturated double bond), and a compound having a (meth)acryloyl group is preferred. Monomer component (a) contains a monomer (a-1) having two or more (meth)acryloyl groups. Monomer (a-1) may be a compound having two (meth)acryloyl groups (hereinafter also referred to as monomer (a-1-2)) or a compound having three or more (meth)acryloyl groups (hereinafter also referred to as monomer (a-1-1)). The number of (meth)acryloyl groups in monomer (a-1) and monomer (a-1-1) may be, for example, 10 or less, 8 or less, 6 or less, or 4 or less. Monomer (a-1) may be a cyclic monomer having a cyclic structure or an acyclic monomer not having a cyclic structure, but it is preferable that it be an acyclic monomer. If monomer (a-1) is an acyclic monomer, ester bonds can be more densely present in the polymer formed, and the ammonia blockability of the hard coat layer tends to be further improved. Monomer (a-1) is preferably composed of a high proportion of monomer (a-1-1) from the perspective that it is easier to obtain a hard coat layer with higher hardness. The proportion of monomer (a-1-1) in monomer (a-1) (i.e., the content of monomer (a-1-1) based on the total amount of mo