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JP-2026076251-A - Electron beam curable composition and method for producing the same

JP2026076251AJP 2026076251 AJP2026076251 AJP 2026076251AJP-2026076251-A

Abstract

[Problem] To provide an electron beam curable composition containing (meth)acrylic (meth)acrylate, wherein the cured film exhibits excellent weather resistance, flexibility, toughness, and a smooth surface finish. [Solution] An electron beam curable composition containing the following component (A). • Component (A): A (meth)acrylate polymer having (meth)acryloyl groups in its side chains, with a (meth)acrylic equivalent of 500 to 2,000 (g/eq), a weight-average molecular weight of 10,000 or less, and a glass transition temperature of -15 to 80°C in the uncured state. A polymer. [Selection Diagram] None

Inventors

  • 望月 克信
  • 岩見 みづほ

Assignees

  • 東亞合成株式会社

Dates

Publication Date
20260511
Application Date
20260121

Claims (13)

  1. An electron beam curable composition containing the following component (A). • Component (A): A (meth)acrylate polymer having (meth)acryloyl groups in its side chains, with a (meth)acrylic equivalent of 500 to 2,000 (g/eq), a weight-average molecular weight of 10,000 or less, and a glass transition temperature of -15 to 80°C in the uncured state. A polymer.
  2. The component (A) is a copolymer (a1) [hereinafter referred to as "polymer (a1)"] comprising a structural unit derived from a (meth)acrylate monomer (a1-1) that does not have a reactive group and a structural unit derived from a (meth)acrylate monomer (a1-2) that has a reactive group, and a compound (a) having a group that reacts with the reactive group and a (meth)acryloyl group via the reactive group. 2) The electron beam curable composition according to claim 1, which is a reaction product with [hereinafter referred to as "unsaturated compound (a2)"].
  3. The copolymer (a1) is composed of a (meth)acrylate monomer having a reactive group (a1 The electron beam curable composition according to claim 2, wherein (2) is a (meth)acrylate monomer having a reactive group selected from the group consisting of epoxy groups, carboxyl groups, hydroxyl groups, and isocyanate groups.
  4. The electron beam curable composition according to claim 2 or 3, wherein the unsaturated compound (a2) is (meth)acrylic acid.
  5. Furthermore, compound (B) having an ethylenically unsaturated group other than component (A) (hereinafter referred to as "component ( An electron beam curable composition according to any one of claims 1 to 4, comprising (B)).
  6. The electron beam curable composition according to claim 5, comprising 5 to 95% by weight of component (A) and 95 to 5% by weight of component (B) in a total of 100% by weight of component (A) and component (B).
  7. The electron beam curable composition according to claim 5 or claim 6, wherein the total double bond equivalent of component (A) and component (B) is 500 to 2500 g/eq.
  8. Furthermore, if the mixture contains an organic solvent (C) (hereinafter referred to as "component (C)"), and contains component (B) in proportion to 100 parts by weight of component (A), then component (A) and component (B) An electron beam curable composition according to any one of claims 1 to 7, comprising 150 parts by weight or less of component (C) per 100 parts by weight of the total of the other components.
  9. An electron beam curable composition for coating agents comprising the electron beam curable composition according to any one of claims 1 to 8.
  10. An electron beam curable composition for outdoor coating agents comprising the electron beam curable composition described in claim 9.
  11. A copolymer (a1) consisting of a constituent unit (a1-1) derived from a (meth)acrylate monomer without reactive groups and a constituent unit (a1-2) derived from a (meth)acrylate monomer with reactive groups is reacted with the unsaturated compound (a2) to obtain the copolymer (a1), A method for producing an electron beam curable composition, comprising the step of adding the unsaturated compound (a2) via the reactive group.
  12. The copolymer (a1) is composed of a (meth)acrylate monomer having a reactive group (a1 A method for producing an electron beam curable composition according to claim 11, wherein (2) is a (meth)acrylate monomer having a reactive group selected from the group consisting of epoxy groups, carboxyl groups, hydroxyl groups, and isocyanate groups.
  13. A method for producing an electron beam curable composition according to claim 12, wherein the unsaturated compound (a2) is (meth)acrylic acid.

Description

This invention relates to an electron beam curable composition whose cured film exhibits excellent weather resistance, flexibility, toughness, and finish, and is suitable for use as a coating agent. (Meth)acrylate polymers, which have (meth)acryloyl groups in their side chains, so-called (meth)acrylic (meth)acrylates, have a main chain skeleton composed of a (meth)acrylic structure, and therefore, when used as coating agents, they exhibit excellent weather resistance. On the other hand, active energy ray curable compositions are known as coating agents. Active energy ray curable compositions have advantages over thermosetting compositions, such as shorter curing times and lower energy requirements. In particular, electron beam curable compositions have advantages over ultraviolet curable compositions, such as the ability to cure even with high pigment content because they do not require the inclusion of a photopolymerization initiator, and the excellent weather resistance of the cured film. As electron beam curable coating agent compositions using (meth)acrylic (meth)acrylate, the compositions described in Patent Documents 1 to 4 are known. Patent Document 1 describes an electron beam curable composition comprising an acrylic poly(meth)acrylate having a coating film glass transition temperature of 150°C or higher, and a polyhydric alcohol (meth)acrylate containing two or more (meth)acryloyl groups and having an (meth)acryloyl group equivalent of 150 or less. Patent Document 2 describes an electron beam curable coating comprising: A: colored particles; B: acrylic poly(meth)acrylate containing 1.5 moles or more (meth)acryloyl groups per 1,000 molecular weight; and C: polyhydric alcohol (meth)acrylate containing two or more (meth)acryloyl groups and having a (meth)acryloyl equivalent of 150 or less. Patent Document 3 describes an electron beam curable composition containing an electron beam curable acrylic polymer that includes ultraviolet-stable monomer units and polymerizable double bonds in its side chains. Patent Document 4 describes an electron beam curable coating composition comprising inorganic fine particles (A) having a specific Knoop hardness, and a poly(meth)acrylate (B) having a glass transition temperature (Tg) of 20 to 200°C and two or more (meth)acryloyl groups. Japanese Patent Application Publication No. 08-047671Japanese Patent Application Publication No. 08-257498Japanese Patent Publication No. 2000-109523Japanese Patent Publication No. 2005-075835Japanese Patent Publication No. 2021-105170 The present invention relates to an electron beam curable composition comprising the following component (A). Component (A): A (meth)acrylate polymer having (meth)acryloyl groups in its side chains, having a (meth)acrylic equivalent of 500 to 2,000 (g/eq), a weight-average molecular weight (hereinafter referred to as "Mw") of 10,000 or less, and a glass transition temperature (hereinafter referred to as "Tg") in the uncured state of -15 to 80°C. As component (A), a reaction product is preferred between a copolymer (a1) [hereinafter referred to as "polymer (a1)"] containing a constituent unit derived from a (meth)acrylate monomer (a1-1) that does not have a reactive group and a constituent unit derived from a (meth)acrylate monomer (a1-2) that has a reactive group, and a compound (a2) [hereinafter referred to as "unsaturated compound (a2)"] having a group that reacts with the reactive group and a (meth)acryloyl group via the reactive group. The following describes component (A), the electron beam curable composition, and the method of use in detail. In this invention, "(meth)acrylate polymer" means a polymer containing (meth)acrylate as the main component of its constituent units, "(meth)acrylate" means acrylate and/or methacrylate, "(meth)acrylic" means acrylic and/or methacrylic, and "(meth)acryloyl" means acryloyl and/or methacryloyl. 1. Ingredients (A) Component (A) is a (meth)acrylate polymer having (meth)acryloyl groups in its side chains, having a (meth)acrylic equivalent of 500 to 2,000 g/eq, a Mw of 10,000 or less, and a Tg in the uncured state of -15 to 80°C. The (meth)acrylic equivalent of component (A) is 500 to 2,000 g/eq. If the (meth)acrylic equivalent is less than 500 g/eq, the flexibility (elongation) of the cured film will decrease, and if it exceeds 2,000 g/eq, the weather resistance of the cured film will decrease. The (meth)acrylic equivalent of component (A) is preferably 600 to 1,500 g/eq, and more preferably 700 to 1,200 g/eq. In this invention, (meth)acrylic equivalent (g/eq) represents the weight (g) per equivalent (eq) of (meth)acryloyl groups. A higher value indicates a lower concentration of (meth)acryloyl groups, while a lower value indicates a higher concentration. The acrylic equivalent can be calculated using the following formula. In the following formula, the number of moles of (meth)acryloyl groups in component (A) is the number of moles of (meth)acryloyl groups added to