PHOTOCURABLE INKJET PRINTING INK COMPOSITION

Abstract

A photocurable inkjet printing ink composition contains (A) to (C) below: (A) a chlorinated polyolefin; (B) monofunctional monomer 1 with a glass transition temperature (Tg) of 0 C. or below; and (C) monofunctional monomer 2 with a glass transition temperature (Tg) of 60 C. or above; wherein the content of (A) in the ink composition is 0.2 percent by mass or higher; the total content of (B) and (C) in the ink composition is 40 percent by mass or higher; and the mass-based ratio of the content of (C) and that of (B), or (C)/(B), is 0.80 to 3.00. The composition makes inkjet printing possible on the surfaces of molded products of polyolefins.

Claims

1. A photocurable inkjet printing ink composition containing (A) to (C) below: (A) a chlorinated polyolefin; (B) monofunctional monomer 1 with a glass transition temperature (Tg) of 0 C. or below; and (C) monofunctional monomer 2 with a glass transition temperature (Tg) of 60 C. or above; wherein: a content of (A) in the ink composition is 0.2 percent by mass or higher; a total content of (B) and (C) in the ink composition is 40 percent by mass or higher; and a mass-based ratio of a content of (C) and a content of (B), or (C)/(B), is 0.80 to 3.00.

Description

EXAMPLES

Examples 1 to 5 and Comparative Examples 1 to 4

[0101] Preparation of Photocurable Inkjet Printing Ink Composition The present invention is explained in greater detail below by giving examples, but the present invention is not limited to these examples. It should be noted that, unless otherwise specified, % indicates percent by mass, while part indicates part by mass.

[0102] The materials used in the following Examples and Comparative Examples are listed below.

[0103] [Viscosity Measurement of Ink Compositions]

[0104] The photocurable inkjet printing ink composition obtained under Examples 1 to 5 and Comparative Examples 1 to 4 were each measured for viscosity at 25 C. using a viscometer (product name: Viscometer Model RE215L, manufactured by Toki Sangyo). The results are shown in Table 1.

[0105] [Adhesion to Polypropylene Film (PP)]

[0106] The photocurable inkjet printing ink composition obtained under Examples 1 to 5 and Comparative Examples 1 to 4 were each applied on the surface of a polypropylene film using a No. 4 bar coater, and then irradiated with ultraviolet light and cured. On the surface of the obtained cured coating film, an ink composition (containing 13.0 percent by mass of vinyl caprolactam, 25.0 percent by mass of isobornyl acrylate, 45.4 percent by mass of benzyl acrylate, and other materials such as polymerization initiator and pigment) was applied using a No. 4 bar coater and then cured.

[0107] On the surface of the cured ink film, a piece of Nichiban's cellophane tape was attached, after which the cellophane tape was peeled and the degree of peeling of the cured ink film surface (degree of separation of the interface between the polypropylene film and the cured layer of each photocurable inkjet printing ink composition) was evaluated visually.

[0108] : There was no peeling.

[0109] : The coating film peeled completely.

[0110] [Tackiness]

[0111] The photocurable inkjet printing ink composition obtained under Examples 1 to 5 and Comparative Examples 1 to 4 were each applied on the surfaces of two polypropylene films using a No. 4 bar coater, and then irradiated with ultraviolet light to obtain cured coating films.

[0112] The cured coating films on the surfaces of the obtained two polypropylene films were placed on top of each other and then separated, to check the degree of sticking.

[0113] : Sticking did not occur.

[0114] : Sticking occurred, but the cured coating films did not peel when the films were separated.

[0115] : The cured coating films stuck to each other and peeled when the films were separated.

TABLE-US-00001 TABLE 1 Examples Comparative Examples Composition 1 2 3 4 5 1 2 3 4 Inorganic Aluminum oxide (grain size 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 pigment 80 nm, AEROXIDE Alu-C, Nippon Aerosil, solids content 10%) Photocurable ACMO (Tg = 145 C., 45.0 49.1 50.92 30.0 50.0 57.1 resins monofunctional monomer 2) V#190 (Tg = 67 C., 27.1 31.0 30.68 22.5 22.5 42.1 32.00 53.1 15 monofunctional monomer 1) HDDA (Tg = 43 C., 10.0 bifunctional monomer) IBXA (Tg = 97 C., 40.6 monofunctional monomer 2) VCAP (Tg = 125 C., 40.6 monofunctional monomer 2) CN371NS (Tg = 39 C., 4.0 4.0 4.0 amine-modified oligomer) Chlorinated 814HS 10 2 0.50 15 15 10 0.1 15 10 polyolefin Photopolymerization TPO 12 12 12 12 12 12 12 12 12 initiator Additives Dioctyl maleate 1.9 1.9 1.9 1.9 1.9 1.9 1.9 1.9 1.9 Quinone-based 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 polymerization inhibitor Silicone-based surface 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 active agent BYK-315N (solids content 25%) Total 100 100 100 100 100 100 100 100.0 100 Evaluations Viscosity (cps) 28 12.3 8.5 74.9 57.6 28 8.2 53 99 PP adhesion X X X Tackiness X Monofunctional 27.1 31.0 30.7 22.5 22.5 42.1 32.0 53.1 15.0 monomer 1 Monofunctional 45.0 49.1 50.9 40.6 40.6 30.0 50.0 0.0 57.1 monomer 2 Monofunctional 1.66 1.58 1.66 1.80 1.80 0.71 1.56 0.00 3.81 monomer 1/ Monofunctional monomer 2

[0116] From the results shown in Table 1 above, the ink composition proposed by the present invention presents such effects as excellent adhesion and low tackiness, based on Examples 1 to 5 that provide photocurable inkjet printing ink composition according to the present invention.

[0117] Looking at the results of Comparative Examples 1 to 4, however, tackiness manifested in Comparative Example 1 wherein the mass-based ratio of the content of (B) and that of (C) were low. Adhesion was poor in Comparative Example 2 wherein the content of (A) was small, in Comparative Example 3 wherein no (C) was contained, and in Comparative Example 4 wherein the mass-based ratio of the content of (B) and that of (C) were high.

[0118] These results show that, as a photocurable inkjet printing ink composition having a specific compositional makeup, the present invention delivers a good balance of the effect of exhibiting sufficient adhesion to molded products of polypropylene and other polyolefins and the effect of keeping the tackiness of the ink coating film low.