JP7329419B2 - Active energy ray-curable compression varnish composition - Google Patents

Description

The present invention relates to a compression varnish composition that cures with active energy rays such as ultraviolet rays.

In the past, sealed letters were used to send information in a concealed state, but now it is possible to write information on the inside of a V-shaped or Z-shaped postcard and attach it to the postcard while keeping it concealed. Postcards have come into use, and these are generally collectively referred to as information carrying sheets.

The adhesive used for this information-carrying sheet is required to be easy to peel but difficult to re-adhere. and a plasticizer and a composition consisting of fatty acid calcium (Patent Document 1). However, such water-based adhesives have many problems, such as requiring a long time for drying after application and that the substrate paper tends to expand, contract, and warp due to moisture absorption.

Therefore, as an adhesive that can deal with these problems, an ultraviolet curable adhesive that can be cured in a short time has been proposed. One example of this is an acrylic oligomer with a specified molecular weight and structure, and two or more types of acrylic photopolymerization. Japanese Patent Application Laid-Open No. 2002-200312, etc., comprising a photopolymerization initiator and a photopolymerization initiator. Such an ultraviolet curable composition is used by applying a resin to a base material and then photocuring it, and then bonding the coated surfaces together after curing and pressing them together. Instead, it may be left for several hours to a day. In particular, when the standing time is long, the cured layer expands and contracts under the influence of temperature and humidity, causing warping, which may cause problems in the subsequent bonding process. Therefore, there is room for improvement in terms of stable adhesion and suppression of warpage.

Japanese Patent No. 5008934 Japanese Patent No. 4422820

The problem of the present invention is that it can be used for laminate sheets and the like typified by information-carrying sheets, does not easily warp even after being cured with active energy rays and left for a long time, and is stable by laminating and crimping. To provide an active energy ray-curable pressure-bonding varnish composition having good adhesion and peelability.

The invention according to claim 1 comprises a bisphenol A ethylene oxide-modified diacrylate (A), an alkylene oxide skeleton di(meth)acrylate (B), a non-functional acrylic polymer (C), and a photopolymerization initiator (D ) and, with respect to the total solid content, the amount of (A) is 30 to 65% by weight, the amount of (B) is 10 to 35% by weight, and the amount of (C) is 3 to 35%. % by weight , and (C) has a weight average molecular weight of 2,000 to 5,000 .

The invention according to claim 2 provides the active energy ray-curable pressure-bonding varnish composition according to claim 1, wherein the (B) is tripropylene glycol diacrylate.

The composition of the present invention is hard to warp even after being cured by active energy rays and left for a long time, and it is possible to secure stable adhesion and peel off by bonding and pressure bonding. It is useful as a compression varnish composition for use in

The composition of the ultraviolet curable resin composition of the present invention comprises a bisphenol A ethylene oxide-modified diacrylate (A), a di(meth)acrylate having an alkylene oxide skeleton (B), a non-functional acrylic polymer (C), and photopolymerization. Initiator (D). In addition, in this specification, (meth)acrylate includes both acrylate and methacrylate.

The bisphenol A ethylene oxide-modified diacrylate (A) used in the present invention is a resin having a high cured product hardness and a fast curing. It is one of the main components that make up the applied cured film. The total number of ethylene oxide modifications (hereinafter referred to as EO modifications) added per molecule is preferably 6 to 14, more preferably 8 to 12, and particularly preferably 10.

The content of (A) is preferably 30 to 65% by weight, more preferably 35 to 60% by weight, based on the total solid content. By making it 30% by weight or more, it becomes possible to secure an appropriate peeling force, and by making it 65% by weight or less, it is possible to secure sufficient compatibility and storage stability as a composition.

The diacrylate (B) having an alkylene oxide skeleton used in the present invention is a bifunctional monomer having an ether skeleton that is blended for the purpose of improving the curability of the composition and is highly compatible with (A). For example, there are ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate and the like, which can be used alone or in combination of two or more. Among these, tripropylene glycol diacrylate is preferable in terms of compatibility. If it is monofunctional, the adhesion is not stable, and if it is trifunctional or higher, warping increases due to cure shrinkage.

The content of (B) with respect to the total solid content is preferably 10 to 35% by weight, more preferably 15 to 30% by weight. Sufficient reactivity can be ensured by making it 15 weight% or more, and appropriate adhesiveness can be ensured by making it 35 weight% or less.

The non-functional acrylic polymer (C) used in the present invention is a plasticizer-like component that does not participate in the curing reaction. play a role in The weight average molecular weight (hereinafter Mw) is 2,000 to 5,000, preferably 2,300 to 4,500, more preferably 2,500 to 4,000. If it is less than 2,000 or more than 5,000, it is not possible because the required adhesion cannot be secured. The Mw was calculated by measuring the molecular weight in terms of standard polystyrene by gel permeation chromatography using a column using a styrene-divinylbenzene-based packing material and using a tetrahydrofuran eluent.

The content of (C) with respect to the total solid content is preferably 3 to 35% by weight, more preferably 5 to 30% by weight. When the content is 3% by weight or more, it is possible to sufficiently prevent the adhesive from being left behind when peeled off, and when the content is 35% by weight or less, sufficient compatibility and storage stability can be ensured.

The photopolymerization initiator (D) used in the present invention produces radicals when irradiated with ultraviolet rays, electron beams, or the like, and the radicals trigger a polymerization reaction. general-purpose photopolymerization initiators such as Curability can be imparted over a wide wavelength range from the ultraviolet region to the visible light region by arbitrarily selecting the light absorption wavelength of the polymerization initiator. Specifically, 2,2-dimethoxy-1,2-diphenylethan-1-one is a benzyl ketal system, and 1-hydroxy-cyclohexyl-phenyl-ketone and 1-[4-(2- hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one is 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropane-1 as α-aminoacetophenone -on includes acylphosphine oxides such as 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide and bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, either singly or in combination of two or more can be used in combination.

Among the above (D), it is preferable to include an α-hydroxyacetophenone type that is resistant to yellowing and an α-aminoacetophenone type that is excellent in surface curability in a thin film. In particular, when the cured film has a thickness of 20 μm or less, tackiness tends to remain on the surface due to inhibition of curing by oxygen. Commercially available products include α-hydroxyacetophenone-based Omnirad 184 and α-aminoacetophenone-based Omnirad 907 (trade name: manufactured by iGM).

The content of (D) is preferably 5 to 15 parts by weight, more preferably 8 to 12 parts by weight, per 100 parts by weight of the radically polymerizable component. By blending in this range, the composition can be efficiently cured. When α-hydroxyacetophenone type and α-aminoacetophenone type are used in combination, the former is preferably 1 and the latter is preferably 0.4 to 1.0.

The composition of the present invention may optionally contain a leveling agent, a reactive diluent, a tackifier, an antioxidant pigment, a dye, a light stabilizer, an antifoaming agent, a thickener, and an ultraviolet ray as long as the performance is not impaired. Various additives such as absorbents and wettability modifiers may be included.

Leveling agents include polydimethylsiloxane, polyether-modified polydimethylsiloxane, polyester-modified polydimethylsiloxane, and the like, which can be used alone or in combination of two or more. Among these, polyester-modified polydimethylsiloxane is preferred because of its excellent compatibility with (C). The amount to be blended with respect to the total solid content is preferably 0.03 to 0.5% by weight, and commercially available products include BYK-UV3570 (trade name: manufactured by BYK Chemie Japan).

The viscosity of the composition at 25° C. is preferably 80 to 10,000 mPa·s, more preferably 100 to 5,000 mPa·s. When the viscosity is 80 mPa·s or more, it becomes easy to secure a sufficient coating amount, and when it is 10,000 mPa·s or less, sufficient coating smoothness can be secured.

Hereinafter, the present invention will be described in more detail with reference to examples and comparative examples, but these are specific examples and are not intended to limit the invention in particular. Unless otherwise specified, the measurement was performed at a room temperature of 25° C. and a relative humidity of 65%. Moreover, the compounding quantity shows a weight part.

Examples 1-3
In the light-shielding bottle, M-2100 (trade name: manufactured by Miwon Co., total number of EO modified 10) as (A) and M-220 (trade name: manufactured by Miwon Co., tripropylene glycol diacrylate) as (B). , UP-1000 (trade name: manufactured by Toagosei Co., Ltd., Mw 3,000) as (C), Omnirad 907 (trade name: manufactured by iGM, α-aminoacetophenone) and Omnirad 184 (manufactured by iGM, α -Hydroxyacetophenone type), M-300 (trade name: Miwon Co., Ltd., trimethylolpropane triacrylate) as a reactive diluent, BYK-UV3570 (trade name: BYK Chemie Japan Co., Ltd., polyester modified poly Dimethylsiloxane) was added in the amount shown in Table 1, and stirred using a stirring and defoaming machine until uniform to prepare pressure bonding varnish compositions of Examples 1 to 3.

Comparative Examples 1-12
In addition to the materials used in the examples, SUA-023 (trade name: manufactured by Asia Industry Co., Ltd., polyether urethane acrylate) and epoxy ester 3002A (trade name: manufactured by Kyoeisha Chemical Co., Ltd., epoxy acrylate) are used as oligomers, and A is used as a monomer. -DOG (trade name: Shin-Nakamura Chemical Co., Ltd., dioxane diacrylate) and light acrylate PO-A (trade name: Kyoeisha Chemical Co., Ltd., phenoxyethyl acrylate), UP-1080 (trade name: Toagosei) as a plasticizer Co., Ltd., Mw 6,000) and UP-1021 (trade name: Toagosei Co., Ltd., Mw 1,600) and US-6100 (trade name: Toagosei Co., Ltd., alkoxysilyl group-containing acrylic polymer) and Hexamall DINCH (trade name) : BASF Japan Co., Ltd., carboxylic acid ester type) and FZ-100 (trade name: Asia Industry Co., Ltd., polyurethane type) are used, and the formulation shown in Table 1 is stirred using a stirring deaerator until it becomes uniform. Compression varnish compositions of Comparative Examples 1-12 were prepared.

Preparation of evaluation sheet A 250 mm × 150 mm, 50 μm thick easy-adhesive PET film (Toyobo A4300) was coated with a pressure-bonding varnish composition to a film thickness of 20 μm, and subjected to electrodeless UV irradiation manufactured by Fusion UV System Japan. Using the apparatus F300S/LC-6B, a sheet was prepared by curing under the conditions of an H bulb output of 1,200 mW/cm ² and an integrated light amount of 50 mJ/cm ² , and two sheets of this sheet were prepared, and the cured resin surfaces were placed on each other. They were superimposed and laminated at 60° C. and 0.4 MPa using an ML-480 type laminator (type of roll: heat-resistant silicon) manufactured by MCK to prepare a sheet for evaluation.

Table 1

The evaluation method was as follows.

Viscosity: Using a cone plate type viscometer RC-550 manufactured by Toki Sangyo Co., Ltd., 25 ± 1 ° C with a cone angle of 3 ° R 17.65, the rotation speed is 50 rpm for viscosity ranges of 500 mPa s or less, and 20 rpm for 500 to 2000 mPa s , 2000-5000 mPa·s were measured at 10 rpm.

Curability: Using a sheet after ultraviolet curing, the degree of stickiness on the surface of the cured resin was checked by finger touch.

Peel strength: Cut the laminated sheet into 150 mm × 25 mm, use a tensile tester manufactured by Techno Graph, perform T-shaped peeling at a peeling speed of 300 mm / min, 0.1 N or more ○, less than 0.1 N × and

Warpage: The amount of floatation at four locations on the edge of the sheet after UV curing was measured.

Zipping: The case where zipping was observed during the peel force measurement was evaluated as x, and the case where there was no zipping was evaluated as ◯.

Total light transmittance: One sheet after UV curing is measured in accordance with JISK7361-1 using a haze meter Haze-gard 2 manufactured by Toyo Seiki Seisakusho, and the evaluation is 90% or more as ○, less than 90% as x. did.

Haze: One sheet after UV curing was measured according to JISK7361-1 using a haze meter Haze-gard 2 manufactured by Toyo Seiki Seisakusho.

Table 2 shows the evaluation results of the examples.
Table 2

The pressure-bonding varnish compositions of Examples had good viscosity, curability, peeling force, warpage, zipping, total light transmittance and haze evaluation.

On the other hand, Comparative Example 1 using ureac instead of (A) had a large warpage, Comparative Example 2 using epoxy acrylate, Comparative Examples 3 to 5 using other monomers instead of (B), and instead of (C) Comparative Examples 7 and 8 using acrylic polymers with different molecular weights all have weak peeling force, Comparative Example 6 not blending (B), Comparative Example 9 using an acrylic polymer having a functional group instead of (C) Compatibility is poor, Comparative Examples 10 and 11 using a phthalate plasticizer and polyurethane instead of (C) have poor curability, and Comparative Example 12 that does not contain (C) has poor zipping. It was not suitable for invention.

The composition of the present invention is hard to warp even after being cured by active energy rays and left for a long time, and it is possible to secure stable adhesion and peel off by bonding and pressure bonding. It is useful as a compression varnish resin suitable for

Claims (2)

Bisphenol A ethylene oxide-modified diacrylate (A), alkylene oxide skeleton di(meth)acrylate (B), non-functional acrylic polymer (C), and photopolymerization initiator (D), all solid The amount of (A) is 30 to 65% by weight, the amount of (B) is 10 to 35% by weight, the amount of (C) is 3 to 35% by weight, and (C ) has a weight average molecular weight of 2,000 to 5,000 . 2. The active energy ray-curable pressure-bonding varnish composition according to claim 1, wherein said (B) is tripropylene glycol diacrylate.