JP2813429B2 - Manufacturing method of electron beam curing type pre-coated steel sheet - Google Patents

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial application field) The present invention relates to a precoated steel sheet having excellent boiling water resistance, mainly for indoor use.

(Prior art) Pre-painted steel sheets have reduced the cost of painting compared to the conventional method of painting after processing using a continuous mass production system. The items required for this precoated steel sheet are to withstand high-level forming, and because it has a variety of uses, besides workability, corrosion resistance, weather resistance, chemical resistance, stain resistance, boiling water resistance, etc. It has various performances. Furthermore, since continuous mass production is assumed,
Short-time treatment is also indispensable condition. For heat-curing paints, long baking furnaces with high temperatures were installed on the line to increase the line speed.

However, in recent years, radiation-curable paints have attracted attention for precoated steel sheets, and various compositions that adhere directly to steel sheets have been proposed. However, there is no flat plate that satisfies the adhesiveness after forming such as pre-coated steel sheet and high performance such as high corrosion resistance and boiling water resistance even if the adhesiveness is good. It is believed that these performance deficiencies are essentially due to poor adhesion of the paint. In order to compensate for this drawback, the current situation is that a conventional thermosetting primer layer is used for the layer in contact with the metal plate, and only the top coat layer is of a radiation-curable type. At present, only half of the production line is utilized.

(Problems to be Solved by the Invention) The present invention requires a long baking furnace for heat curing of a precoated steel sheet which improves the above-mentioned various drawbacks and has excellent formability, corrosion resistance, chemical resistance, and especially excellent boiling water resistance. It does not provide a manufacturing method.

[Configuration of the invention]

(Means for Solving the Problems) In the present invention, a primer composition containing the following (A), (B) and (C) is applied on a steel plate, and when a solvent is contained, the primer composition is dried after solvent drying. A steel sheet coated with a material and a sheet provided with an electron beam-curable layer containing an uncured color pigment on a substrate sheet having releasability are laminated so that the primer layer and the electron beam-curable layer are in contact with each other, This is a method for producing a precoated steel sheet, in which a base sheet having a peeling property is peeled off and then irradiated with an electron beam.

Further, the present invention provides a steel sheet coated with a primer composition containing the following (A), (B) and (C), and coated with the primer composition after drying with a solvent when containing a solvent, After laminating a sheet provided with an electron beam-curable layer containing an uncured color pigment on a substrate sheet having releasability so that the primer layer and the electron beam-curable layer are in contact with each other, and then irradiating with an electron beam, This is a method for producing a precoated steel sheet in which a base sheet having peelability is peeled.

(A) a compound having an ethylenically unsaturated double bond (B) a compound having an ethylenically unsaturated double bond and a carboxyl group and / or a monohydroxyalkyl methacrylate or a phosphate compound of the same acrylate (C) chromate Rust preventive pigment In the present invention, (A) the compound having an ethylenically unsaturated double bond includes unsaturated polyesters, polyester poly (meth) acrylate, epoxy poly (meth) acrylate, polyurethane poly (meth) acrylate, polyether poly ( (Meth) acrylate, polyol poly (meth) acrylate, acrylic resin having an ethylenically unsaturated double bond in the side chain, diallyl phthalates, ethylene glycol di (meth) acrylate, propylene glycol (meth) acrylate, diethyl Glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, tetraethylene glycol di (meth) acrylate , Styrene, α-methylstyrene,
Methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, (meth) acrylic acid 2
-Ethylhexyl, hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, (meth)
Examples include acrylamide, (meth) acrylonitrile, glycidyl (meth) acrylate, phenoxyethyl (meth) acrylate, trimethylolpropanetrithioglycolate, trimethylolpropanetrithiopropionate, and the like, or a mixture thereof.

In the present invention, (B) the compound having an ethylenically unsaturated double bond and a carboxyl group includes, for example, a compound represented by the general formula: (R ¹ is a hydrogen atom or a methyl group, n is an integer of 0 and 1 to 6), ethylene glycol (meth) acrylate phthalate,
Ethylene glycol (meth) acrylate succinate, ethylene glycol (meth) acrylate maleate, propylene glycol (meth) acrylate phthalate, propylene glycol (meth) acrylate succinate, propylene glycol (meth) acrylate maleate and the like are used.

Examples of the monohydroxyalkyl methacrylate or the acrylate phosphate compound include those having the following structure.

(However, R ¹ is a hydrogen atom or a methyl group, m is 1 or 2, n is (3-m).) These can be used alone or in combination of two or more.

In the present invention, (C) chromate-based rust preventive pigments include, for example, K ₂ O-4CrO ₃ .4Zn.3H ₂ O, ZnCrO ₄ .4Zn (O
One or more of H) ₂ , SrCrO ₄ , BaK ₂ (CrO ₄ ) _{2 and the} like can be used.

The electron beam-curable primer composition of the present invention comprises the components (A), (B) and (C) described above, as long as the primer performance and curability are not impaired.
Solvents, pigments, fillers, thermoplastic resins, thermosetting resins, plasticizers, and other additives can be used as needed.

The composition comprising (A) and (B) in the electron beam-curable primer composition of the present invention is known as a conventional radiation-curable composition. At present, the optimum amount is determined from the balance between the water resistance or boiling water resistance and the adhesiveness, and it has been extremely difficult to satisfy both. However, the composition of the present invention
By adding the chromate-based rust-preventive pigment as the component (C), the blending range of the component (B) can be significantly expanded. That is, even if the composition comprising the conventional (A) and (B) had good adhesion and poor boiling water resistance, the boiling water resistance can be remarkably improved by adding only a small amount of (C). Becomes The mixing range of the components (A), (B) and (C) is not particularly limited, and is determined by the steel sheet material to be used, the degree of processing, and the dose of electron beam irradiation. The proportion of the component (B) in the mixture of the components (B) and (B) is 3 to 95% by weight.
A composition containing 3 to 300 parts by weight of the component (C) based on parts by weight is suitable.

The component (C) in the electron beam-curable primer composition of the present invention can be dispersed using a known dispersing machine such as a three-roll mill, a paint conditioner, a ball mill, and a sand mill.

Next, a method for producing the electron beam-curable precoated steel sheet of the present invention will be described.

Although the steel sheet material to which the electron beam-curable primer composition of the present invention can be applied is not particularly limited, a steel sheet which has been subjected to various plating and chemical conversion treatments from the viewpoint of adhesion and corrosion resistance is preferable. The method can be carried out using a conventionally known coater, for example, a roll coater, a curtain flow coater, a knife coater or the like.
When a solvent is contained in the primer composition, it is necessary to remove the solvent in the next step.

On the other hand, an uncured electron beam-curable layer is provided on a peelable substrate sheet, laminated so that the primer layer coated on the steel sheet and the electron beam-curable layer are in contact with each other, and before irradiation with an electron beam. A precoated steel sheet can be manufactured by peeling the base sheet or by peeling the base sheet after irradiating the electron beam.

Examples of the substrate sheet having releasability according to the present invention include various plastic films such as a polyester film, a polyamide film, a cellophane film, a polyethylene film and a polypropylene film, paper, polypropylene-impregnated paper, metal foil, and a laminate of two or more of these. . Further, the surface of each of the above-described various base sheets may be subjected to a treatment such as a peeling treatment. In the production method of the present invention, since the radiation is applied through the base sheet, the base sheet is desirably radiolucent.
Further, as the base sheet, a sheet having unevenness may be provided, or a sheet capable of forming a mat or an uneven pattern may be used.

The uncured electron beam-curable layer formed on the releasable substrate sheet of the present invention includes a compound having an ethylenically unsaturated double bond, a coloring pigment, and if necessary, an ethylenically unsaturated double bond. Obtained by mixing compounds that do not. Examples of the compound having an ethylenically unsaturated double bond include unsaturated polyesters, polyester poly (meth) acrylate, epoxy poly (meth) acrylate, polyurethane poly (meth) acrylate, polyether poly (meth) acrylate, and polyol poly ( (Meth) acrylates, acrylic resins having an ethylenically unsaturated double bond in the side chain, diacrylphthalates,
Ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, di Pentaerythritol hexa (meth) acrylate, tetraethylene glycol di (meth) acrylate, styrene, α-methylstyrene, (meth) acrylic acid, methyl (meth) acrylate,
Ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, (meth)
Hydroxyethyl acrylate, hydroxypropyl (meth) acrylate, (meth) acrylamide, (meth)
Acrylonitrile, glycidyl (meth) acrylate,
Examples include phenoxyethyl (meth) acrylate, trimethylolpropanetrithioglycolate, trimethylolpropanetrithiopropionate, and the like, or a mixture thereof. Polymers having no ethylenically unsaturated double bond include saturated polyester resins, polyamide resins,
Polyurethane resin, amino acid resin, diallyl phthalate resin, ketone resin, cellulose resin, (meth) acrylic resin, polystyrene resin, styrene-maleic acid copolymer resin, epoxy resin, polyvinyl chloride resin, ethylene-
Vinyl acetate copolymer resin, polyvinyl alcohol resin,
Examples include synthetic rubbers such as polyvinyl acetate resin, butyral resin, vinyl chloride-vinyl acetate copolymer resin, and polybutadiene resin, and mixtures thereof. In the present invention, in order to maintain good processability and adhesiveness, it is preferable to use an electron beam-curable layer mainly composed of a prepolymer and using no or a small amount of a monomer. Or 10 to 90% by weight of prepolymer and / or monomer and 90 to 10% by weight of polymer having no ethylenically unsaturated double bond
Is also effective. A polymerization inhibitor such as hydroquinone, hydroquinone monomethyl ether and benzoquinone may be added to suppress the dark reaction and increase the stability during storage.

In the present invention, the electron beam-curable layer contains a coloring pigment for the purpose of concealing the underlying color, and the type, concentration, etc. thereof are determined as necessary.

In the present invention, the laminating temperature of the electron beam-curable layer on the substrate sheet having releasability and the primer layer on the steel sheet varies depending on the properties of both layers, but a temperature from room temperature to about 100 ° C. is sufficient.

In the present invention, whether the irradiation with the electron beam is performed through a peelable base sheet or after the peeling may be determined based on the convenience of the process or the affinity of the base sheet to be used with the electron beam cured layer. However, when the purpose is to prevent oxygen inhibition of the radical polymerization reaction or to use it as a protective sheet until the next step, the former is preferred.

The irradiation dose varies depending on the type of the primer composition and the electron beam-curable layer, but is selected in the range of 5 to 300 kGy.

As an accelerator for generating an electron beam, there are devices such as a scan type and a curtain, and a low acceleration voltage type may be used.

(Examples) Hereinafter, the present invention will be described with reference to examples. In the examples, parts mean parts by weight.

Example 1 Oligoester acrylate Aronix M-6200 (trade name, manufactured by Toa Gosei Chemical Industry Co., Ltd.) 20 parts KAYARAD TC-110S (trade name, manufactured by Nippon Kayaku Co., Ltd.) 30 parts Aronix M-5600 (trade name, Towa Gosei Co., Ltd.) Chemical Co., Ltd.) 50 parts Taipaque CR-90 (trade name, manufactured by Ishihara Sangyo Co., Ltd.) 36 parts Strontium chromate (trade name, manufactured by Kikuchi Pigment Industry Co., Ltd.) 8 parts Thus, a primer composition was obtained. This was applied to an electroplated zinc steel sheet at 5 g / m ² . On the other hand, an electron beam-curable layer having the following composition was prepared, coated on one side of a 50μ polyester film so as to have a dry film thickness of 20μ, dried at 100 ° C for 1 minute, and uncured on a releasable base sheet. An electron beam curable layer was obtained.

Next, the primer layer on the steel sheet and the electron beam-curable layer on the polyester film are bonded together at room temperature so that they are in contact with each other. Then, 100 kGy of electron beam is irradiated from the polyester film side, and the electron beam-curable layer and The primer layer was cured and the polyester film was peeled off.

The performance of the precoated steel sheet obtained as described above was as shown in Table 1.

Example 2 Aronix M-56 in the primer composition of Example 1
Using 30 parts of KAYARAD PM-2 (trade name, manufactured by Nippon Kayaku Co., Ltd.) instead of 00, a primer composition was obtained using a paint conditioner as a dispersing machine.

Hereinafter, the same materials as in Example 1 were used, and a precoated steel sheet was obtained in the same manner. The performance was as shown in Table 1.

Comparative Example 1 A primer composition was obtained without using the strontium chromate of Example 1. Hereinafter, the same material as in Example 1 was used, and a precoated steel sheet was obtained in the same manner.

 The performance was as shown in Table 1.

Comparative Example 2 A primer composition was obtained without using the strontium chromate of Example 2. Hereinafter, using the same materials as in Example 2, a precoated steel sheet was obtained in the same manner.

 The performance was as shown in Table 1.

Example 3 Instead of strontium chromate in the primer composition of Example 1, 10 parts of zinc chromate (Kikuchi Pigment Industry Co., Ltd.) was used, and a triple roll was used to obtain a primer composition.

Hereinafter, the same materials as in Example 1 were used, and a precoated steel sheet was obtained in the same manner. The performance was as shown in Table 1.

Example 4 Aronix M-56 in the primer composition of Example 1
A primer composition was obtained using 60 parts of OE-A120 (trade name, manufactured by Nippon Shokubai Chemical Industry Co., Ltd.) instead of 00.

Hereinafter, a precoated steel sheet was obtained using the same materials as in Example 1 and in the same manner. The performance was as shown in Table 1.

[Effects of the Invention] The primer composition for an electron beam-curable precoated steel sheet of the present invention and the method for producing a precoated steel sheet using the same,
No baking furnace is required, and the primer layer and top coat layer can be cured at once. In particular, it has become possible to produce a precoated steel sheet having excellent workability and boiling water resistance.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI // C08F283 / 01 C08F283 / 01 290/00 290/00 (56) References JP-A-61-111379 (JP, A) JP-A-48-732 (JP, A) JP-A-60-222246 (JP, A) Shinji Iwai et al., "Paint Handbook (Re-enhanced Edition)" (September 10, 1958) Sangyo Tosho Stock Company publication pages 513-517 (58) Fields investigated (Int.Cl. ⁶ , DB name) C09D 4/00-4/06 C09D 5/00 B32B 15/08 B32B 15/18 C08F 283/01 C08F 290 / 00-290/14

Claims (2)

(57) [Claims] 1. A primer composition containing the following (A), (B) and (C) is coated on a steel sheet, and when containing a solvent, after drying with a solvent, the steel sheet coated with the primer composition is peeled off. A sheet in which an electron beam-curable layer containing an uncured color pigment is provided on a substrate sheet having an adhesive property is laminated so that the primer layer and the electron beam-curable layer are in contact with each other, and the substrate sheet having a releasability is peeled off. And then irradiating with an electron beam. (A) a compound having an ethylenically unsaturated double bond (B) a compound having an ethylenically unsaturated double bond and a carboxyl group and / or a monohydroxyalkyl methacrylate or a phosphate compound of the same acrylate (C) chromate Rust prevention pigment 2. A primer composition containing the following (A), (B) and (C) is coated on a steel sheet, and when a solvent is contained, the solvent is dried and then peeled off from the steel sheet coated with the primer composition. After laminating a sheet provided with an electron beam-curable layer containing an uncured color pigment on a substrate sheet having a property, so that the primer layer and the electron beam-curable layer are in contact with each other, and irradiating with an electron beam, and then peeling off A method for producing a precoated steel sheet, wherein a base sheet having a property is peeled off. (A) a compound having an ethylenically unsaturated double bond (B) a compound having an ethylenically unsaturated double bond and a carboxyl group and / or a monohydroxyalkyl methacrylate or a phosphate compound of the same acrylate (C) chromate Rust prevention pigment