JPS6321695B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electron beam curable composition that has excellent adhesion to a substrate.

In recent years, with the spread of electron beam irradiation equipment, many electron beam curable compositions have been proposed. These compositions are generally applied to a substrate and then cured by electron beam irradiation to be used in applications such as paints, adhesives, and inks. Among these, compositions whose main component is a monomer having ethylenically unsaturated bonds are excellent in that they have fast reactivity and can adjust the strength of the cured coating film, and are also advantageous in efficiently curing thick coating films. It is. However, chain polymerization of such ethylenically unsaturated monomers is known to cause significant volume shrinkage, which has the drawback of causing poor adhesion of the coating film to the substrate upon curing. Another drawback is that the presence of even a trace amount of oxygen during irradiation significantly inhibits polymerization.

Although various compositions have been proposed to improve the above-mentioned drawbacks, they are not necessarily satisfactory. As one such composition, a system consisting of a thiol compound and an ethylenically unsaturated compound is known. This system is excellent in that it is not affected by oxygen, but its adhesion to the substrate is insufficient.

The present invention maintains the advantages of a combination system of a thiol compound and an ethylenically unsaturated compound, such as fast curing speed and the ability to cure thick coatings.
The object of the present invention is to provide an electron beam curable composition that has improved adhesion to a substrate, which is a drawback of the composition.

According to the research of the present inventors, in the combination system of thiol compound and ethylenically unsaturated monomer, -SH
It has been found that the addition of organosilanes having groups or ethylenically unsaturated bonds and hydrolyzable groups is very effective in achieving the above. That is, the electron beam curable composition of the present invention is characterized by containing an ethylenically unsaturated monomer, a thiol compound having an -SH group, and an organosilane having an -SH group or an ethylenically unsaturated bond. It is something to do.

The present invention will be explained in more detail below. In the following description, "%" and "part" are based on weight unless otherwise specified.

As the ethylenically unsaturated compound of the present invention, any compound having radical polymerizability can be used. Specifically, for example, acrylate oligomers having acryloyl groups such as polyester acrylate, urethane acrylate, and epoxy acrylate, diene oligomers such as polybutadiene oligomers and cyclopentadiene oligomers, unsaturated esters, etc. are used alone or in combination of two or more. can do.

The thiol compounds of the present invention include pentaerythritol tetrakis thioglycolate, trimethylolethanetris-β-mercaptopropionate, pentaerythritol tetrakis-
Compounds having two or more -SH groups, including tri- or tetrafunctional compounds such as 3-mercaptopropyl ether, are used.

These thiol compounds are preferably used in an amount of 1 to 100 parts per 100 parts of the ethylenically unsaturated compound.

As the organosilane, those having one or more hydrolyzable groups such as a halogen bonded to a Si atom, an alkoxy group having 1 to 3 carbon atoms, or an acyloxy group in addition to an -SH group or an ethylenically unsaturated bond are used. . Specifically, for example, γ-acryloylpropyltrimethoxysilane, γ-acryloylpropylmethyldimethoxysilane, γ-acryloylpropylhydrodiene dimethoxysilane, γ-acryloylpropyldimethylmethoxysilane, γ-acryloylpropyldihydrodienemethoxysilane, γ-Acryloylpropyltrichlorosilane, γ-Acryloylpropylmethyldichlorosilane, γ-Acryloylpropylhydrodiene dichlorosilane, γ-Acryloylpropyldimethylchlorosilane, γ-Acryloylpropyldihydrodienechlorosilane, γ
-Acryloylpropyltriacyloxysilane,
γ-acryloylpropylmethyl diacyloxysilane, γ-acryloylpropylhydrodiene diacyloxysilane, γ-acryloylpropyldimethylacyloxysilane, γ-acryloylpropyldihydrodiene acyloxysilane, etc.; Alternatively, those substituted with a mercapto group or those in which a propylene group is substituted with a butylene group or an ethylene group are used.

The above-mentioned organosilane has the property that the hydrolyzable group directly bonded to the Si atom easily reacts with the hydroxyl group or adsorbed moisture on the surface of the base material to form a silanol bond, and thus firmly adheres to the base material. On the other hand, the ethylenically unsaturated bonds contained in the organosilane or -
The SH group is formed with the aforementioned ethylenically unsaturated compound or thiol compound under electron beam irradiation by forming RS・+CH ₂ =CHCH ₂ R′→RSCH ₂ C〓HCH ₂ R′, RSCH ₂ C〓HCH ₂ R′+RSH
→RSCH ₂ CH ₂ CH 2 CH ₂ R'+RS・ Forms a type of copolymer between organosilane, ethylenically unsaturated compound, and thiol compound by bonding through the reaction or by participating in chain polymerization by the generated radicals. do. For this reason, the composition as a whole is firmly bonded to the substrate after curing via the aforementioned silanol bonds.

Such organosilane is preferably added in a proportion of 0.1 to 10 parts per 100 parts of the ethylenically unsaturated compound. If it is less than 0.1 part, the effect of improving adhesion to the base material will be extremely small, and if it is added in excess of 10 parts, the adhesive layer will become brittle and delamination will easily occur.

The composition of the present invention has the above-mentioned three components as main components, but can contain up to 100 parts of optional components per 100 parts of the ethylenically unsaturated compound.

Such optional components include, for example, drying oils such as linseed oil, eno oil, and tung oil; phenolic resins, polyamide resins, natural rubber derivatives, cellulose derivatives, vinyl resins, polyolefins, petroleum resins, unsaturated alkyd resins, etc. natural or synthetic resins; colorants consisting of dyes or pigments; surfactants,
These include plasticizers, inorganic fillers, and polymerization inhibitors to provide storage stability.

The composition of the present invention is prepared by kneading the above-mentioned compositions in a conventional manner using a kneading machine such as a three-roll mill, attritor, ball mill, or sand grinder.
It is usually adjusted to a viscosity of about 0.01 to 1000 poise.

As mentioned above, the composition of the present invention is characterized by excellent adhesion to a substrate due to the presence of organosilane. For this reason, a wide range of base materials can be used, including paper,
plastic film sheet or block,
Suitable for coating various inorganic materials, wood boards, etc.

The composition of the present invention is applied to the above-mentioned base material by any method such as gravure coating method, roll coating method, flexo reverse method, calendar method, spray coating method, etc. to a desired coating thickness, and if necessary, After overlapping another base material (for example, in the case of adhesive use), it is irradiated with an electron beam and cured.

The electron beam used for curing is emitted from various electron beam accelerators such as Kotscroft-Walton type, Van de Graaff type, resonant transformer type, insulated core transformer type, linear type, Dynamitron type, and high frequency type.
An electron beam with an energy in the range of 1000 KeV, preferably 100-300 KeV is used. In order to irradiate a coating film with an electron beam, a method is adopted in which a spot beam is scanned at high speed or a continuous curtain-shaped beam is irradiated from a linear filament. Generally, surface irradiation is performed by continuously moving the object to be irradiated. As the irradiation dose, for example, a range of 0.1 to 100 Mrad is used.

As described above, according to the present invention, in addition to an ethylenically unsaturated compound and a thiol, an organosilane having a -SH group or an unsaturated bond is included, thereby providing excellent electron beam curability and adhesion to a substrate. An electron beam curable composition having the following properties is provided. This composition also has the following characteristics compared to conventional curable compositions.

(b) Because it is cured with electron beam, coloration caused by sensitizers that occurs in conventional ultraviolet curable compositions does not occur.

(b) The curing speed is fast, and there is no need to leave it standing unlike conventional compositions using peroxide catalysts.

C. Electron beams have strong penetrating power and can cure thick coatings, and at the same time, they cure without being affected by additives such as pigments. This property cannot be obtained with UV-curable paints.

EXAMPLES Hereinafter, the present invention will be explained in more detail with reference to Examples.

Example 1 100 parts of a reaction mixture of 120 parts of maleic acid and 130 parts of n-butyl glycidyl ether, 5 parts of pentaerythritol tetrathioglycolate, and 0.05 part of γ-mercaptopropyltrimethoxysilane were mixed. This adhesive was applied at a rate of 2.5 g/m ² using a gravure roll onto a 12 μ thick biaxially stretched polyethylene terephthalate film that had been corona treated, and then a 50 μ thick polyethylene film that had been similarly corona treated was applied on top of this. Pasted. This laminated film was transferred to a low-energy electron accelerator (Energy).
Manufactured by Science, Electro Curtain CB20d50/30)
The adhesive was cured with a dose of 10 Mrad. Adhesive strength of the obtained laminated film (pulling speed 300
mm/min, tension angle T-shaped) was 800 g/15 mm.

Example 2 Polybutadiene (B-1000, manufactured by Nippon Soda Co., Ltd.)
100 parts of trimethylolethane tris β-mercaptopropionate and 0.05 parts of γ-acryloylpropyltrimethoxysilane were mixed. This adhesive was applied to a corona-treated polyethylene terephthalate film with a thickness of 12 μm at a rate of 3.0 g/m ² using a wire bar, and a corona-treated stretched polypropylene film with a thickness of 30 μm was laminated on top of this. . This laminated film was prepared in Example 1.
Electron beam irradiation was performed in the same manner as above, and the same adhesive strength was obtained.

Claims (1)

[Claims] 1 Ethylenically unsaturated compound and two or more -
An electron beam curable composition comprising a thiol compound having an SH group, and an organosilane having a --SH group or an ethylenically unsaturated bond and a hydrolyzable group.