JP5797314B1 - Building board manufacturing method - Google Patents

Abstract

[PROBLEMS] To provide not only excellent initial adhesion between a cured coating and a top coating of an active energy ray-curable ink, but also no deterioration of adhesion or cracking over time, and water resistance and weather resistance. The manufacturing method of the high quality building board provided with the coating film excellent in is provided. An active energy ray-curable ink containing a monomer and / or oligomer having an ethylenically unsaturated group is coated on a base material on which an undercoat has been applied, and then irradiated with active energy rays to form a cured coating film. And then a top coat paint is applied onto the formed cured coating film to produce a building board, and the reaction rate of the curing reaction when forming the cured coating film is 80. %, And the surface temperature of the cured coating film when the top coat is applied is higher than the theoretical value of the glass transition temperature of the cured coating film calculated from the Fox equation. It is a manufacturing method. [Selection figure] None

Description

  The present invention relates to a method for producing a building board. More specifically, the present invention not only has excellent initial adhesion, but also has excellent water resistance and weather resistance without deterioration of adhesion or cracking over time. The present invention relates to a method for manufacturing a building board provided with a film.

  Conventionally, various building boards have been used for exteriors and interiors of houses and the like. For example, for exterior applications, inorganic building materials such as ceramic siding boards and ALC panels have come to be used, and patterns are provided on the surface. And such a building board can be cured, for example, by applying an undercoating on the surface of the base material and irradiating the undercoating film with an ink composition, for example, an active energy ray such as ultraviolet rays. (Hereinafter, this may be referred to as “active energy ray curable ink” or simply “ink”) to form a desired pattern, and then cured. Yes. This active energy ray-curable ink is cured by specific active energy rays, especially when applied by ink jet. Therefore, as in the case of conventional solvent inks and water-based inks, volatilization / drying of water and organic solvents is required. It is difficult to cause a discharge failure such as nozzle clogging due to, and it is quick-drying so that productivity can be improved.

  By the way, the active energy ray-curable ink has reactive monomers and oligomers as a composition, and these react to form a dense cross-linked structure, whereby the ink is cured. For this reason, although such ink has the above-mentioned advantageous surface, a dense cross-linking structure is formed in the cured coating film. When painted, it generally has the disadvantage of poor adhesion.

  In this respect, Patent Document 1 discloses a construction in which a clear paint containing a crosslinking component as an essential component is applied to a UV curable ink (UV ink) at a curing rate of 50 to 90% and then dried. A method for manufacturing a plate is disclosed. According to this method, the adhesion between the UV ink layer and the clear coating is achieved by crosslinking and / or interacting a polar group such as an acrylic group (acryloyl group) in the UV ink with a crosslinking component contained in the clear paint. Can be improved. However, although the method of Patent Document 1 is thought to improve the adhesion immediately after coating, since the clear paint contains a crosslinking component as an essential component, the storage stability of the clear paint is likely to decrease, and in some cases, the clear paint is crosslinked. It was inferior in the selectivity of the top coating material, for example, it was necessary to store the components separately in two or more liquids without blending the components, and to mix and coat the crosslinking component immediately before use. Furthermore, the clear paint is applied while the curing rate of the UV ink is as low as 60%. In such a low curing rate, many active groups such as acrylic groups (acryloyl groups) and vinyl groups are present. It remains in the UV ink without being reacted. Therefore, when an object to be coated is used in an environment that receives ultraviolet rays (for example, outdoors), the reaction of the active groups remaining in the UV ink starts and proceeds again, and the UV ink layer is further cured. The internal stress of the coating film increased with time, and there was a problem that the adhesion between the base material, the undercoat layer, the UV ink layer, and the clear layer was easily lowered and cracks were likely to occur.

JP 2010-167334 A

  Therefore, the inventors of the present invention have intensively studied to solve such problems, and as a result, when applying a top coating to a cured coating of an active energy ray-curable ink, when forming a cured coating. In addition to increasing the reaction rate of the curing coating, and by setting the surface temperature of the cured coating when applying the top coating to a predetermined range, the initial coating of the top coating is possible even when the cured coating has been cured. In addition to excellent adhesion, it has been found that there is no deterioration of adhesion over time or generation of cracks, and that it is possible to produce a building board that has been coated with excellent water resistance and weather resistance, and the present invention Completed.

  Therefore, the object of the present invention is not only excellent in the initial adhesion between the cured coating film of the active energy ray-curable ink and the top coating, but also has no deterioration in adhesion over time or occurrence of cracks, etc., and water resistance It is providing the manufacturing method of a building board provided with the coating film excellent in weather resistance.

That is, in the present invention, an active energy ray-curable ink containing a monomer and / or oligomer having an ethylenically unsaturated group is coated on a substrate on which an undercoat has been applied, and then cured by irradiation with active energy rays. A method for manufacturing a building board, in which a coating film is formed, and then a top board paint is applied on the formed cured coating film to manufacture a building board,
The reaction rate of the curing reaction when forming the cured coating film is 80% or more, and the surface temperature of the cured coating film when applying the top coating is calculated from the formula of Fox. It is a manufacturing method of a building board characterized by being higher than the theoretical value of a glass transition temperature.

  In the present invention, the active energy ray-curable ink preferably has an average number of functional groups of ethylenically unsaturated groups of 2 or less.

  Moreover, in this invention, it is preferable that the reaction rate of the hardening reaction at the time of forming the said cured coating film is larger than 90%.

  Moreover, in this invention, it is preferable that the surface temperature of the cured coating film at the time of applying the said top coat is 10 degreeC or more higher than the said theoretical glass transition temperature.

In the present invention, the monomer having an ethylenically unsaturated group includes isobornyl (meth) acrylate, 2-phenoxyethyl (meth) acrylate, 1,6-hexanediol di (meth) acrylate, and 1,9-nona. is preferably one or more selected from emissions diol di (meth) acrylate.

  In the present invention, the oligomer having an ethylenically unsaturated group is one or two selected from aliphatic urethane (meth) acrylate, polyester (meth) acrylate, silicone (meth) acrylate, and epoxy (meth) acrylate. It is preferable that it is a seed or more.

  Furthermore, in the present invention, it is preferable that the active energy ray-curable ink and / or the top coat be applied by inkjet.

  According to the present invention, not only is the initial adhesion between the cured coating film of the active energy ray-curable ink and the top coating material excellent, but there is no decrease in adhesion over time or the occurrence of cracks, and water resistance and weather resistance. It is possible to produce high-quality building boards that are painted with excellent properties.

Embodiments of the present invention will be specifically described below.
<Base material>
In the present invention, as the base material, a general base material used as an interior / exterior material for a building can be used without any particular limitation. Examples of the base material include inorganic materials such as flexible board, calcium silicate board, gypsum slag bar light board, calcium carbonate board, wood chip cement board, precast concrete board, lightweight foamed concrete (ALC) board, gypsum board and glass. Including various plastic materials such as materials, polyethylene, polypropylene, polyvinyl chloride, polyvinylidene chloride, ABS resin, melamine resin, acrylic resin, polyester (polyethylene terephthalate, etc.) resin and polyurethane resin, and alloys such as aluminum, iron and stainless steel A metal etc. are mentioned and these 2 or more types of materials can also be combined. Moreover, various surface treatments, sealers and / or primer coatings may be applied to the substrate surface in advance. The shape of the base material may be smooth or uneven.

<Undercoating>
In the present invention, as the coating for forming the undercoat coating layer, a solvent-based coating using an organic solvent as a main solvent, a water-based coating using water as a main solvent, a solvent-free coating, various enamel coatings of powder coating, Or a clear paint can be used. Preferably, water-based paints, solvent-free paints, and powder paints that can reduce emission of volatile organic compounds (VOC) are more preferable from the viewpoint of the environment. More preferably, it is a one-component water-based paint that is easy to handle rather than a solvent-free paint that is difficult to handle itself or a powder paint that requires drying and baking at a high temperature of 200 ° C. or higher. Good. The undercoat paint can contain various colored and / or extender pigments.

  Examples of the method for forming the undercoat coating film layer in the present invention include methods using various conventionally used coating means such as air spray, airless spray, roll coater and flow coater. In addition, before and after undercoating, the substrate can be heated as necessary to promote drying and / or curing.

If necessary, the undercoat paint can be applied in two or more times, that is, the same kind of paint or a plurality of different kinds of paints can be applied. As the coating amount of the undercoat paint, the coating amount per coating is preferably ²⁰ to 200 g / m ² . In particular, when an enamel paint is used as an undercoat, if it is less than 20 g / m ² , the concealability is inferior, and if it exceeds 200 g / m ² , drying and / or curing tends to be poor, and the coating film performance deteriorates. To do. About the film thickness after undercoat coating, it is preferable that it is 5-40 micrometers per layer.

  Various resins such as acrylic resin, alkyd resin, polyester resin, polyurethane resin, epoxy resin, silicone resin and fluororesin can be used as the resin used in the paint for forming the undercoat film. Of these resins, two or more kinds of resins may be used in combination. Furthermore, coloring and / or extender pigments, thickeners, dispersants, antifoaming agents, anti-settling agents, anti-fungal agents, antiseptics, UV absorption, etc., in order to impart various functions to the paint for forming the undercoat film An agent, a light stabilizer, or the like may be added as appropriate.

<Active energy ray curable ink>
As the active energy ray-curable ink in the present invention, an ink that is cured by irradiation with various active energy rays such as ultraviolet rays (UV) or electron beams (EB) to form a cured coating film can be used. Preferably, UV curable ink is preferable from the viewpoint of cost and capital investment. In the present invention, the “cured coating film” refers to a cured coating film obtained by curing an active energy ray-curable ink unless otherwise specified.

  As a curing reaction when the active energy ray-curable ink is cured to form a cured coating film, various reaction mechanisms such as anionic polymerization, cationic polymerization, or radical polymerization can be used, and in order to improve curability, Two or more of these can also be combined.

  In the present invention, the reaction rate of the curing reaction when forming the cured coating film needs to be 80% or more. If the reaction rate is less than 80%, most of the active groups such as ethylenically unsaturated groups remain unreacted in the ink, and the object to be coated was used in an environment that receives ultraviolet rays (for example, outdoors). In such a case, the reaction of the remaining active groups starts and proceeds to further cure the cured coating film. As a result, the internal stress increases with time, and the base material, the undercoat coating film, the cured coating film, and the top coating film It is not preferable because the adhesiveness of each coating film and the occurrence of cracks are likely to occur. In addition, a coating film in which most of the active groups remain unreacted is fragile and easily attracts coating deterioration factors such as water and oxygen, leading to a decrease in water resistance and weather resistance. The reaction rate is more preferably greater than 90%.

Here, the reaction rate of the curing reaction can be determined by measuring as follows. That is, the monomer and / or oligomer having an ethylenically unsaturated group, which is the main component of the active energy ray-curable ink, is preferably an acryloyl group or a methacryloyl group (hereinafter collectively referred to as “( (Sometimes referred to as a “meth) acryloyl group”), and CH out-of-plane variation of 810 cm ⁻¹ [CH ₂ ═C (R) —C (═O) O— derived from this (meth) acryloyl group The change in absorption intensity (change before and after the curing reaction) of angular vibration (R is hydrogen or methyl group)] is measured with a Fourier transform infrared spectrophotometer (FT-IR method) and remains after the reaction. The ratio (%) of residual unsaturated groups can be calculated and obtained from the following formula (1).
Reaction rate (%) = 100 (%) − residual unsaturated group (%) (1)
Here, the residual unsaturated group (%) is calculated by the following formula (2) on the basis of absorption of C═O stretching vibration (1725 cm ⁻¹ ) that does not change due to the curing reaction.
Residual unsaturated groups (%) = [(absorption intensity ratio after curing reaction) / (absorption intensity ratio before curing reaction)] × 100 (2)
Incidentally, before and after the curing reaction in the formula (2) "absorption intensity ratio", in the case of (meth) acryloyl groups is calculated from (the absorption intensity of 810 cm ^-1) / (absorption intensity of 1725 cm ^-1).

In addition to the (meth) acryloyl group as the ethylenically unsaturated group, for example, a vinyl group (1625 cm ^-1 ; C = C stretching vibration of CH ₂ = CH-), an allyl group (1646 cm ^-1 ; CH ₂ = The reaction rate can be calculated in the same manner as for C—C stretching vibration of CH—CH ₂ —. In addition, when there are two or more types of ethylenically unsaturated groups of monomers and / or oligomers contained in the ink, residual unsaturated groups (%) are obtained using the above formula (2) for each ethylenically unsaturated group. The reaction rate can be obtained from the above formula (1), assuming that the sum of them is the residual unsaturated group (%) of the ink (cured coating film).

  The active energy ray-curable ink in the invention contains a monomer and / or oligomer having an ethylenically unsaturated group. Here, as the monomer and / or oligomer having an ethylenically unsaturated group in the present invention, as described later, those having a plurality of ethylenically unsaturated groups (hereinafter sometimes simply referred to as “functional groups”). May be used singly or in combination of two or more, but the average number of functional groups determined based on the number of ethylenically unsaturated groups of the monomer and / or oligomer contained in that case may be 2 or less preferable. When the average functional group number is increased, the crosslink density of the cured coating film tends to increase when the active energy ray-curable ink is cured. When the top coating is performed on the ink layer, the adhesion of the top coating is weakened, and the initial adhesion tends to decrease.

The average number of functional groups of such ethylenically unsaturated groups is calculated from the following formula (3).
Average number of functional groups =
[Total number of ethylenically unsaturated groups contained in monomer and / or oligomer] / [Total number of molecules of monomer and / or oligomer] Formula (3)
Here, the “total number of ethylenically unsaturated groups contained in the monomer and / or oligomer” in the formula (3) is the total number of ethylenically unsaturated groups per molecule of the monomer or oligomer. Calculated by multiplying by the number of molecules. When plural types of monomers or oligomers are blended in the ink, the number of ethylenically unsaturated groups is calculated for each type, and the total number of ethylenically unsaturated groups means the number of ethylenically unsaturated groups. Thus, in order to make the average functional group number in the active energy ray-curable ink to be 2 or less, the number of functional groups, molecular weight, blending amount and the like of the monomer and / or oligomer used are variously changed and appropriately combined. be able to.

As a means for curing the active energy ray-curable ink, various light sources such as a high-pressure mercury lamp, a metal halide lamp, and an LED lamp can be used, and the main wavelength is preferably 300 to 450 nm. The peak illuminance of the active energy ray for curing the active energy ray curable ink is preferably in the range of 300 to 3000 mW / cm ² . When the peak illuminance is less than 300 mW / cm ² , the irradiation intensity of the active energy ray is weak and it is difficult to make the reaction rate 80% or more, so the coating performance such as adhesion and weather resistance is lowered. To do. When the peak illuminance is greater than 3000 mW / cm ^{2, the} heat generated from the active energy ray generation source leads to deterioration of the ink layer formed by the undercoat film and / or the active energy ray curable ink. Decrease, generation of cracks and discoloration of the coating film occur. The peak illuminance can be appropriately adjusted not only by adjusting the output of the active energy ray but also by adjusting the distance between the source of the active energy ray and the irradiated object.

Furthermore, the irradiation amount of the active energy ray is preferably 100 to 2000 mJ / cm < ² >. When the integrated light amount of the active energy ray is less than 100 mJ / cm ² , it is difficult to set the reaction rate to 80% or more, and the coating performance such as adhesion and weather resistance is lowered. When the accumulated amount of active energy rays is greater than 2000 mJ / cm ² , the active energy rays lead to deterioration of the undercoat and / or the cured coating formed by the active energy ray-curable ink, resulting in a decrease in gloss. The coating film performance such as the appearance of the coating film such as the occurrence of cracks and the discoloration of the coating film and the weather resistance is deteriorated. As for the above integrated light quantity, in addition to adjusting the irradiation time of the active energy ray, when the irradiation source and / or the object to be irradiated is irradiated while moving, the moving speed is adjusted as appropriate. Can be adjusted. In the present invention, as described above, in order to set the reaction rate of the curing reaction when forming a cured coating film from the active energy ray-curable ink to 80% or more, the above peak illuminance and integrated light amount are adjusted as appropriate, Can be combined.

  Among the monomers having an ethylenically unsaturated group as described above, examples of those having one ethylenically unsaturated group include stearyl (meth) acrylate, acryloylmorpholine, tridecyl (meth) acrylate, and lauryl (meth) acrylate. , N, N-dimethylacrylamide, decyl (meth) acrylate, isodecyl (meth) acrylate, isobornyl (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentenyl (meth) acrylate, isooctyl (meth) acrylate, octyl (Meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, cyclohexyl (meth) acrylate, 2-phenoxyethyl (meth) acrylate, cyclic trimethylolpropane formal (meta Acrylate, isoamyl (meth) acrylate, 2-ethylhexyl-diglycol (meth) acrylate, ethylene oxide modified 2-ethylhexyl (meth) acrylate, neopentyl glycol (meth) acrylic acid benzoate, 2-hydroxyethyl (meth) acrylate , 2-hydroxyxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, N-vinylcaprolactam, N-vinyl-2-pyrrolidone N-vinylimidazole, tetrahydrofurfuryl (meth) acrylate, methoxydipropylene glycol (meth) acrylate, (2-methyl-2-ethyl-1,3-dioxolane-4-y ) Methyl (meth) acrylate, ethoxy-diethylene glycol (meth) acrylate, various (meth) acrylate monomers such as glycerol monoallyl ether, vinyl monomers, allyl ether monomers, and the like. These may be used alone. Alternatively, two or more kinds can be combined. Preferably, alicyclic monomers such as isobornyl (meth) acrylate, cyclic trimethylolpropane formal (meth) acrylate, and cyclohexyl (meth) acrylate are preferable from the viewpoint of discoloration of the coating film after curing. From the viewpoint of flexibility of the film, 2-phenoxyethyl (meth) acrylate and ethoxy-diethylene glycol acrylate are preferable, and it is preferable to design an ink by combining these.

  Examples of the monomer having two ethylenically unsaturated groups include hydroxypivalate neopentyl glycol di (meth) acrylate, polytetramethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, and triethylene glycol diester. (Meth) acrylate, tetraethylene glycol di (meth) acrylate, polyethylene glycol (200, 400 or 600) di (meth) acrylate, dipropylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, neopentyl glycol Di (meth) acrylate, 1,3-butylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,5-pentanediol di (meth) acrylate Rate, 1,6-hexanediol di (meth) acrylate, 1,7-heptanediol di (meth) acrylate, 1,8-octanediol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, 1,10-decanediol di (meth) acrylate, 2-methyl-1,8-octanediol di (meth) acrylate, 2-butyl-2-ethyl-1,3-propanediol di (meth) acrylate, polytetra Methylene glycol di (meth) acrylate, 3-methyl-1,5-pentanediol di (meth) acrylate, dimethylol-tricyclodecane di (meth) acrylate, bisphenol A di (meth) acrylate, 2- (2′-vinyl Oxyethoxy) ethyl (meth) acrylate, divinylbenzene, a (Meth) acrylate, trimethylolpropane diallyl ether, various (meth) acrylate monomers such as diallyl ether, vinyl monomers, allyl monomers, and alkylene glycol modified products of these monomers. Well, or two or more types can be combined. Preferably, 1,6-hexanediol di (meth) acrylate and 1,9-nonanediol di (meth) acrylate are preferable in terms of toughness, curability, and discoloration of the coated film after curing. Good.

  Furthermore, as a polyfunctional monomer having three or more ethylenically unsaturated groups, for example, pentaerythritol tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, glycerin tri (meth) acrylate, ethoxylated trimethylolpropane tri (Meth) acrylate, propoxylated trimethylolpropane tri (meth) acrylate, ethoxylated glycerin tri (meth) acrylate, tetramethylolmethane tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, trimethylolpropane tetra (meth) acrylate , Ethoxylated pentaerythritol tetra (meth) acrylate, EO-modified diglycerin tetra (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate , Various (meth) acrylate monomers such as dipentaerythritol penta (meth) acrylate and dipentaerythritol hexa (meth) acrylate, allyl ether monomers such as pentaerythritol triallyl ether, and alkylene glycol modified products of these monomers These may be used alone or in combination of two or more.

  About content of the monomer which has the said ethylenically unsaturated group, it is preferable to contain 50-90 mass% with respect to the total amount of ink from a viewpoint of sclerosis | hardenability of an ink or coating-film performance. Moreover, when a monomer and an oligomer contain in an ink, it is preferable that the monomer which has the said 1 ethylenically unsaturated group is 40-90 mass% with respect to the total amount of all the monomers and oligomers.

On the other hand, examples of the oligomer having an ethylenically unsaturated group include (meth) acrylate oligomers having one or more (meth) acryloyl groups, vinyl oligomers having one or more vinyl groups, and allyl oligomers having one or more allyl groups. Various oligomers can be used. In particular, the acrylate oligomer preferably has 2 to 6 functional groups. Specific examples of the acrylate oligomer include amino acrylate oligomer [acrylate oligomer having a plurality of amino groups (-NH ₂ )], urethane acrylate oligomer [acrylate oligomer having a plurality of urethane bonds (-NHCOO-)], epoxy acrylate oligomer [epoxy group Acrylate oligomers], silicone acrylate oligomers [acrylate oligomers having a plurality of siloxane bonds (-SiO-)], ester acrylate oligomers [acrylate oligomers having a plurality of ester bonds (-COO-)], and butadiene acrylate oligomers [with butadiene units. A plurality of acrylate oligomers]. Among these, urethane acrylate oligomers are preferable from the viewpoint of weather resistance and adhesiveness, and aliphatic urethane acrylate oligomers having no aromatic ring in the structure are more preferable. In addition, it is preferable that content of an acrylate oligomer is 1-20 mass% in the total mass of an active energy ray hardening-type ink from the point of sclerosis | hardenability and a viscosity.

Specific examples of the acrylate oligomer include the following, and these may be used alone or in combination of two or more. That is,
Beam set 502H, beam set 505A-6, beam set 550B, beam set 575, beam set AQ-17 (above, manufactured by Arakawa Chemical Industries),
UA-306H, UA-306I, UA-510H, UF-8001G (manufactured by Kyoeisha Chemical Co., Ltd.),
CN929, CN940, CN944B85, CN959, CN961E75, CN961H81, CN962, CN963A80, CN963B80, CN963E75, CN963E80, CN963J75, CN964, CN964A85, CN964E75, CN965, CN965A80, CN966A80, CN966B85, CN966H90, CN966J75, CN966R60, CN968, CN980, CN981, CN981A75, CN981B88, CN982A75, CN982B88, CN982E75, CN982P90, CN983, CN985B88, CN989, CN991, CN996, CN9001, CN9002, CN9004, CN9005, CN9006, CN9007 CN9009, CN9010, CN9011, CN9014, CN9178, CN9788, CN9893 (manufactured by Sartomer Company, Inc.),
U-4HA, U-6HA, U-6LPA, UA-1100H, UA-53H, UA-33H, U-200PA, UA-4200, UA-122P (manufactured by Shin-Nakamura Chemical Co., Ltd.),
New Frontier R-1214, New Frontier R-1301, New Frontier R-1304, New Frontier R-1306X, New Frontier R-1150D (above, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.)
EBECRYL230, EBECRYL244, EBECRYL245, EBECRYL264, EBECRYL265, EBECRYL270, EBECRYL284, EBECRYL285, EBECRYL294, EBECRYL1290, EBECRYL1290, EBECRYL1290, EBECRYL1290, EBECRYL1290
UV-1700B, UV-7600B, UV-7605B, UV-6630B, UV-7000B, UV-7461TE, UV-3000B, UV-3310B, UV-3520TL, UV-3700B (manufactured by Nippon Synthetic Chemical Co., Ltd.),
Art Resin UN-333, UN-1255, UN-2600, UN-2700, UN-5500, UN-5507, UN-6060P, UN-6200, UN-6300, UN-6301, UN-7600, UN-7700, UN-9000PEP, UN-9200A, UN-3320HA, UN-3320HC, UN-904 (above, manufactured by Negami Kogyo Co., Ltd.)
Aronics M-6100, Aronics M-6200, Aronics M-6250, Aronics M-6500, Aronics M-7100, Aronics M-7300K, Aronics M-8030, Aronics M-8060, Aronics M-8530, Aronics M-8560, Various commercially available products such as Aronics M-9050 (manufactured by Toagosei Co., Ltd.) can be used. Moreover, it can synthesize | combine suitably and can be used with the various method obtained by a well-known technique.

  In order to improve the toughness and flexibility of the cured coating film and / or to reduce curing shrinkage, the active energy ray-curable ink in the present invention further contains a molecular weight that does not contain an ethylenically unsaturated group. More than 5000 high molecular weight substances can be added. These polymer substances have high toughness and flexibility in themselves, but the above-described monomer and / or oligomer having an ethylenically unsaturated group undergoes a polymerization reaction derived from the ethylenically unsaturated group. Since it does not occur, toughness and flexibility can be imparted to the coating film, and curing shrinkage can be reduced. Further, by selecting a polymer substance containing a functional group such as a carboxyl group, an epoxy group and a hydroxyl group, the adhesion between the undercoat paint and the overcoat paint can be improved.

Examples of the polymer substance that does not contain an ethylenically unsaturated group include, for example, Dialnal BR-50, Dialnal BR-52, Dialnal BR-60, Dialnal BR-64, Dialnal BR-73, and Dialnal BR-75. , Dialnal BR-77, dialnal BR-80, dialnal BR-82, dialnal BR-83, dialnal BR-84, dialnal BR-85, dialnal BR-87, dialnal BR-88, diamond Narnal BR-90, Dialnal BR-95, Dialnal BR-96, Dialnal BR-100, Dialnal BR-101, Dialnal BR-102, Dialnal BR-105, Dialnal BR-106, Dialnal BR -107, Dialnal BR-108, Dialnal BR-1 0, dialnal BR-1122, dialnal BR-113, dialnal BR-115, dialnal BR-116, dialnal BR-117, dialnal BR-118, dialnal BR-122, dialnal BR-605, Dialnal MB-2539, Dialnal MB-2389, Dialal BR-2660, Dialnal BR-2952, Dialnal MB-3012, Dialnal BR-3015, Dialnal MB-7033, Dialnal MB-2478 (above, (Mitsubishi Rayon)
CAB-551-0.01, CAB-551-0.2, CAB-553-0.4, CAB-531-1, CAB-500-5, CAB-381-0.1, CAB-381-0. 5, CAB-381-2, CAB-321-0.1, CAB-504-0.2, CAB-482-0.5, Solus 2100, Solus 2300, Solus 3050 (above, manufactured by Eastman Chemical Company),
Paraloid A-11, Paraloid A-14, Paraloid A-21, Paraloid B-60, Paraloid B-64, Paraloid B-66, Paraloid B-72, Paraloid B-82, Paraloid B-44, Paraloid B-48N, Various commercially available products such as Paraloid B-67 and Paraloid RG-310 (manufactured by Roam And Haas Company) can be used. In addition, various polymer substances obtained by known techniques can be synthesized and used. Furthermore, these two or more types can be used in combination.

  In addition, the active energy ray-curable ink in the present invention can contain a photopolymerization initiator. Examples of the photopolymerization initiator include radical polymerization initiators such as 2,2-dimethoxy-1,2-diphenylethane-1-one, 1-hydroxy-cyclohexyl-phenyl-ketone, and 2-hydroxy-2-methyl. -1-phenylpropan-1-one, 1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propan-1-one, 2-hydroxy-1- {4- [4- (2-hydroxy-2-methylpropionyl) -benzyl] -phenyl} -2-methyl-propan-1-one, phenylglyoxylic acid methyl ester, 2-methyl-1- [4- (methylthio) Phenyl] -2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone, 2 Dimethylamino-2- (4-methyl-benzyl) -1- (4-morpholin-4-yl-phenyl) -butan-1-one, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide Bis (2,6-dimethoxybenzoyl) -2,4,4-trimethyl-pentylphosphine oxide, 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, 1,2-octanedione, 1- [4 -(Phenylthio) -2- (O-benzoyloxime)], ethanone, 1- [9-ethyl-6- (2-methylbenzoyl) -9H-carbazol-3-yl]-, 1- (O-acetyloxime) ), 2,4-diethylthioxanthone, 2-isopropylthioxanthone, 2-chlorothioxanthone and the like. The singly, or it may be used in combination of two or more. More preferably, 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide is preferable because the appearance of the molecule is discolored after decomposition by irradiation with active energy rays, and coloring of the coating film after curing can be reduced. As content of a photoinitiator, 1-20 mass% is preferable with respect to the total amount of ink, More preferably, it is 5-15 mass%.

  The active energy ray-curable ink in the present invention includes trimethylamine, methyldimethanolamine, triethanolamine, benzophenone, p-diethylaminoacetophenone, ethyl p-dimethylaminobenzoate, p-dimethylaminobenzoate as necessary. Various sensitizers such as isoamyl acid, N, N-dimethylbenzylamine, 4,4′-bis (diethylamino) benzophenone, and polymerization accelerators can be used.

  In addition, the active energy curable ink in the invention may contain a colorant such as a dye or a pigment, but it is preferable to contain a pigment from the viewpoint of weather resistance. Such colorants may be used alone or in combination of two or more. The content of the colorant is preferably 2 to 20% by mass with respect to the total amount of ink. When the content of the colorant is less than 2% by mass, sufficient concealability cannot be obtained, and a large amount of ink must be applied, which is not only inferior in productivity but also causes poor curing and bleeding. It becomes. When the content of the colorant is more than 20% by mass, the viscosity becomes high and the ejection stability is lowered, or the active energy ray is shielded by the pigment, which causes poor curing. As the particle diameter of the colorant, it is preferable that the average particle diameter measured by a dynamic light scattering method is 40 to 500 nm and the cumulative maximum particle diameter is 1 μm or less. When the cumulative maximum particle size is larger than 1 μm, it is not preferable because clogging at the nozzle portion is likely to occur when the ink jet method is used.

  In addition, various surface conditioners can be used for the active energy ray-curable ink in order to improve adhesion to the undercoat and / or improve wettability to the undercoat. Moreover, in order to improve the weather resistance of a coating film, light stabilizers, such as a ultraviolet grade agent and a radical scavenger, can be used for active energy ray curable ink. In order to improve storage stability, various polymerization inhibitors such as hydroquinone compounds can be used.

  Various coating methods of active energy ray curable ink include various printing methods such as ink jet printing, offset printing (flat printing), flexographic printing (letter printing), gravure printing (intaglio printing), screen printing (stencil printing), and the like. However, in order to form a pattern with high designability on a base material, particularly a building interior / exterior material having irregularities on the surface, it is preferably carried out by an ink jet method capable of coating the base material in a non-contact manner. When using the inkjet method, ink can be applied only to a desired portion, so that waste of ink can be reduced and a plate is not required, so that various patterns can be switched in a short time. Become.

  When the active energy ray curable ink is applied by an ink jet method, generally, the ink is heated to 30 to 60 ° C. and discharged in an ink jet head portion in order to make the ink viscosity within an optimum range. Therefore, in order to perform good coating, the surface tension of the active energy ray-curable ink used in the present invention is preferably 20 to 35 mN / m at the discharge temperature. When the surface tension is less than 20 mN / m, the ink excessively spreads on the undercoat coating layer, and the sharpness of the image tends to be lowered. Also, in the head portion, the nozzle tip portion is excessively wet and spreads, and the discharge stability is lowered. When the surface tension of the ink is larger than 35 mN / m, the ink does not spread sufficiently on the undercoat coating layer, and in order to obtain a dark hue, a large amount of ink must be applied, Productivity tends to decrease. The viscosity of the active energy ray-curable ink is preferably 5 to 25 mPa · s at the discharge temperature in order to discharge stably. Moreover, as a method of adjusting the surface tension of the active energy ray-curable ink of the present invention within the above specified range, for example, a method using various surface conditioners and the like can be mentioned.

The application amount of the active energy ray-curable ink is preferably 0.2 to 50 mg / m ² . Moreover, it is preferable that the film thickness after application | coating is 1-50 micrometers.

<Top coat painting>
In the present invention, after the active energy ray-curable ink is applied and cured to form a cured coating film, a top coating is applied on the cured coating film for the purpose of adjusting the surface finish appearance and ensuring durability. Do. As the paint used for the top coating in the present invention, various clear paints such as solvent-based paints, water-based paints, solvent-free paints, and powder paints can be used, preferably from the viewpoint of the environment, VOC Water-based paint, solvent-free paint or powder paint that can reduce discharge can be used. In fields where high weather resistance is not required, such as interior materials, active energy ray-curable clear paints that are quick-drying and excellent in productivity can also be used. Preferably, a water-based paint that is easy to handle in a one-pack type, rather than a solvent-free paint that is difficult to handle itself or a powder paint that requires drying and baking at a high temperature of 200 ° C. or higher in some cases. Of these, water-based clear paint is more preferable. The clear paint in the present invention refers to a transparent paint and means a paint that does not conceal the lower coating layer by coloring. As described below, the finished appearance such as gloss and / or design is adjusted. In order to achieve this, various extender pigments or resin beads can be added as appropriate.

In the present invention, when top coating is performed, the surface temperature of a cured coating film formed from the active energy ray-curable ink (hereinafter sometimes simply referred to as “surface temperature”) is used as the cured coating film. The glass transition temperature must be higher than the theoretical value. Here, the theoretical value [Tg (K)] of the glass transition temperature of the cured coating film is the glass transition of the homopolymer of each polymer component (monomer and oligomer having an ethylenically unsaturated group) that forms the cured coating film. It is calculated using the temperature, and can be obtained using the following Fox formula [Formula (4)].
1 / Tg = (W ₁ / Tg ₁ ) + (W ₂ / Tg ₂ ) +... + (W _n / Tg _n ) (4)
[However, Tg _n is the glass transition temperature of the homopolymer of n kinds of polymer component (a monomer or oligomer having an ethylenically unsaturated group) (K), W _n is the weight of each polymer component It is a fraction. W ₁ + W ₂ +... + W _n = 1. ]

  In the present invention, when the surface temperature of the cured coating film is equal to or lower than the theoretical value (Tg) of the glass transition temperature, the adhesion of the top coating becomes insufficient, and the initial and temporal adhesion decreases. There is a fear. About such a surface temperature, it is more preferable from the point of the adhesiveness of top coat to make it 10 degreeC or more higher than the theoretical value (Tg) of the said glass transition temperature. As described above, the reason why the surface coating temperature is higher than the theoretical value (Tg) of the glass transition temperature to improve the adhesion of the top coating is that the surface temperature is the glass transition temperature. Is higher than the theoretical value (Tg), the crystallinity of the cured coating film is low, so that when the top coating material is applied onto the cured coating film, the top coating material and the cured coating film are sufficiently close to each other. It is presumed that it is easy to fuse and a strong intermolecular interaction is obtained.

  In addition, the surface temperature of the cured coating film when performing top coating is higher than Tg as described above unless it is heated at 200 ° C. or more for a long time, which may adversely affect the coating film. However, particularly when a water-based clear paint is used as the top coat, the surface temperature is preferably 100 ° C. or lower. When the top coat is applied at a temperature higher than 100 ° C., the top coat tends to be defective in film formation, causing coating defects such as foaming and cracking, and overcoating at a temperature higher than the Tg of the cured coating. This is because even in such a case, there is a possibility that good coating film performance cannot be obtained.

  Examples of the method for adjusting the surface temperature of the cured coating film include a method of heating with hot air, a heater, air blowing, a hot plate, or the like, but is not particularly limited. Moreover, as a measuring method of the surface temperature of a cured coating film, although a contact-type thermometer, a non-contact-type thermometer (infrared radiation thermometer), etc. are mentioned, it is not specifically limited.

  As the resin used for such a top coating, various synthetic resins such as acrylic resin, alkyd resin, polyester resin, polyurethane resin, epoxy resin, silicone resin and fluororesin can be used, but are not particularly limited. Of these resins, two or more kinds of resins may be used in combination.

  For the purpose of improving weather resistance, a light stabilizer such as an ultraviolet absorber can be used as the top coating, and two or more of these light stabilizers can be used in combination. Further, in order to adjust the finished appearance such as luster and design, the top coat can be added with various extender pigments or resin beads, and these two or more types can be combined. Furthermore, a silane coupling agent or the like can be added to the top coating material in order to improve the adhesion to the cured film below. Furthermore, in order to impart various functions to the top coat, a thickener, a dispersant, an antifoaming agent, an anti-settling agent, an antifungal agent or an antiseptic may be added as appropriate.

  The surface tension of the top coat in the present invention is preferably 20 to 50 mN / m at 25 ° C. When the surface tension is less than 20 mN / m, bubbles are likely to be generated, so that bubbles remain in the coating film, which tends to cause coating film defects. When a large amount of an antifoaming agent is added to suppress foam, it causes a coating film defect such as repelling when the top coat is applied. When the surface tension of the top coating is higher than 50 mN / m, it becomes difficult to sufficiently spread on the cured coating film, resulting in a decrease in leveling properties and a decrease in coating film appearance. Examples of the method for adjusting the surface tension of the top coating composition of the present invention within the above-specified range include a method using various surface conditioners and the like.

  Examples of the method for forming the top coat layer include a method using various conventionally used coating means such as air spray, airless spray, roll coater, flow coater and ink jet. Examples of the method for drying the top coating include room temperature drying, forced drying by hot air or infrared irradiation, active energy ray irradiation, and the like, and can be appropriately selected according to the type and characteristics of the top coating.

The coating amount of the top coat is preferably ²⁰ to 200 g / m2. When the amount is less than 20 g / m ² , the concealability is inferior. When the amount is more than 200 g / m ² , drying and / or curing tends to be poor, and the coating film performance such as cracking is deteriorated. In addition, about the film thickness after top-coat coating, it is preferable that it is 5-40 micrometers.

  Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the following examples. Hereinafter, unless otherwise specified, “parts by mass” may be simply referred to as “parts” and “% by mass” may be simply referred to as “%”.

Details of the raw materials used are shown below.
<Base material>
Slate plate [150mm x 70mm x 5mm, manufactured by TP Giken Co., Ltd.]
<Sealer>
Water-based Mighty Sealer Multi [cationic water-based paint, trade name manufactured by Dainippon Paint Co., Ltd.]
<Undercoat paint>
DNT View Acrylic [water-based acrylic emulsion paint, trade name made by Dainippon Paint Co., Ltd.]
<Active energy ray curable ink>
Inks 1 to 5 were prepared by blending as shown in Table 1 below (units of composition in the table are parts by mass; the same applies to Table 2).
Specifically, all the raw materials in Table 1 were mixed, kneaded and dissolved in a bead mill for 5 hours, and then filtered through a glass fiber filter having a pore size of 1 μm to remove impurities. The blended raw materials are as follows. In addition, about the average functional group number of the ethylenically unsaturated group of these inks, and the theoretical value (Tg) of the glass transition temperature of a cured coating film, it computed using the above-mentioned Formula (3) and Formula (4), respectively. .
・ MA100 [Carbon black pigment, trade name, manufactured by Mitsubishi Chemical Corporation]
・ Solsperse 32000 [pigment dispersant, trade name, manufactured by Nippon Lubrizol Co., Ltd.]
・ Isobornyl acrylate (monofunctional monomer)
・ N-vinylcaprolactam (monofunctional monomer)
・ 2-phenoxyethyl acrylate (monofunctional monomer)
・ 1,6-hexanediol diacrylate (bifunctional monomer)
・ Trimethylolpropane triacrylate (trifunctional monomer)
・ EBECRYL8210 [aliphatic urethane acrylate, tetrafunctional oligomer, product name manufactured by Daicel Ornex Japan Ltd.]
2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide (photopolymerization initiator)
1-hydroxy-cyclohexyl-phenyl-ketone (photopolymerization initiator, trade name: IRGACURE 184, manufactured by BASF Japan Ltd.)

<Topcoat paint>
A top coat was prepared according to the formulation shown in Table 2 below.
Specifically, all the raw materials in Table 2 were mixed, stirred with a high-speed disperser [Homodisper 2.5, manufactured by Primix Co., Ltd.], and then filtered through a 100 mesh metal net. Impurities were removed. In addition, about each mix | blended raw material, it is as follows.
・ Polydurex G613 [acrylic silicone resin emulsion (solid content 42%), product name, manufactured by Asahi Kasei Chemicals Corporation]
・ Diethylene glycol monobutyl ether (film forming aid)
・ Primal RM-8W [Thickener, trade name of Rohm & Haas Japan Co., Ltd.]
-ACEMATT TS100 (matting agent, trade name manufactured by Evonik)
・ TINUVIN 1130 [Ultraviolet absorber, product name manufactured by BASF Japan Ltd.]
TINUVIN 292 [light stabilizer, trade name manufactured by BASF Japan Ltd.]
・ SN deformer 777 [antifoaming agent, trade name, manufactured by San Nopco)
・ PROXEL XL2 [preservative, trade name, manufactured by Arch Chemicals Japan Ltd.]

<Manufacture of building boards>
[ Reference Example 1]
First, a sealer is coated on the substrate by air spraying so that the coating amount is 100 g / m ² , dried at room temperature for 2 hours, and then an undercoat is coated on the substrate at a coating amount of 100 g / m ² (dry film thickness: 25 μm). ) And sprayed with air spray so as to be dried at room temperature for 1 week.

The active energy ray-curable ink (ink 1) prepared above is applied onto the base coated substrate with an ink jet printer [EB100 (control device), XY100 (conveyance stage), both manufactured by Konica Minolta IJ Ltd.]. Printing was performed so that the coating amount was 7.5 mg / m ² . Thereafter, the ink was cured by irradiating with UV light having an integrated light amount of 50 mJ / cm ² per time at a peak illuminance of 800 mW / cm ² by a metal halide lamp. The reaction rate was adjusted by the number of irradiations, and a cured coating film was formed so that the reaction rate of the curing reaction of ink 1 was 80%. In addition, about the reaction rate of hardening reaction, as above-mentioned, each absorption intensity of 810 cm < ^-1 > and 1725 cm < ^-1 > before and behind hardening reaction was measured by FT-IR method, and the above-mentioned Formula (1) and Formula (2) Calculated from Note that the ink 4 to be described later, the absorption intensity of the acryloyl group (810 cm ^-1) and vinyl groups (1625 cm ^-1) respectively of each absorption intensity of the 1725 cm ^-1 were measured, just as equation (2) The residual unsaturated groups (%) were calculated by using them, and the total of these was used as the residual unsaturated groups (%) in the ink 4, and the reaction rate was calculated from the equation (1).

After printing and curing of the active energy ray curable ink (ink 1), it is heated using a small drying furnace [MO-931, manufactured by Toyama Sangyo Co., Ltd.], and the surface temperature (surface temperature) of the cured coating film is In the state of 51 ° C., the top coating material (clear coating material) prepared above was applied so that the application amount was 80 g / m ² (application thickness: 25 μm). In addition, the measurement of the surface temperature of the cured coating film when performing the top coating was performed using an infrared radiation type non-contact thermometer (ISK-8700II, manufactured by ASONE Co., Ltd.). Then, the base material on which the top coating was applied was dried in a drying oven set at 80 ° C. for 20 minutes, and after taking out, the base material temperature was allowed to reach room temperature to produce a building board according to Reference Example 1. did. Thereafter, the following evaluations were performed.

[Evaluation method]
(1) Initial adhesion (conforms to JIS K 5600-5-6: 1999)
The manufactured building board was cut at intervals of 2 mm in length and width using a cutter knife, and a total of 100 squares were produced, and a cello tape (registered trademark) peel test was performed. The measurement results were as shown in Tables 3-5. The evaluation criteria are as follows.
○: Classification 0-1
Δ: Classification 2
X: Classification 3-5
The classifications 0 to 5 described in 8.3 of JIS K 5600-5-6: 1999 are as follows.
・ Class 0: The edges of the cuts are completely smooth, and there is no peeling to the eyes of any lattice.
・ Category 1: Small peeling of the coating film at the intersection of cuts. The cross-cut portion is clearly not affected by more than 5%.
Classification 2: The coating film is peeled along the edge of the cut and / or at the intersection. The cross-cut part is clearly affected by more than 5% but not more than 15%.
Classification 3: The paint film is partially or completely peeled along the edge of the cut, and / or various parts of the eye are partially or completely peeled off. The cross-cut portion is clearly affected by more than 15% but not more than 35%.
Classification 4: The coating film is partially or completely peeled along the edge of the cut, and / or some eyes are partially or completely peeled off. The cross-cut part is clearly not affected by more than 35%.
・ Category 5: Any of the degree of peeling that cannot be classified by Category 4.

(2) Water resistance (conforms to JIS K 5600-6-2: 1999)
The produced building board was immersed in a constant temperature water bath maintained at 40 ° C., taken out after 240 hours and dried. Thereafter, appearances such as blistering and whitening occurred were observed, and adhesion was evaluated by the same method as the method (1). The results are shown in Tables 3-5. The evaluation criteria are as follows.
○: There is no appearance abnormality such as blistering and whitening, and the adhesion is classified into 0-2.
(Triangle | delta): There is no appearance abnormality, such as a swelling and whitening, and adhesiveness is the classification | category 3-5.
X: Appearance abnormalities such as swelling and whitening are observed.

(3) Accelerated weather resistance (conforms to JIS K 5600-7-7: 2008)
The produced building board was subjected to an accelerated weather resistance test using a weatherometer Ci4000 (manufactured by Atlas) according to the xenon lamp method described in JIS K 5600-7-7. The test was conducted for up to 1000 hours, and the coating film appearance evaluation and adhesion were evaluated in the same manner as in the above method (1). The results are shown in Tables 3-5. The evaluation criteria are as follows.
○: There is no appearance abnormality such as blistering, chalking, cracking, etc., and the adhesion is classified into 0-2.
(Triangle | delta): There is no appearance abnormality, such as swelling, chalking, and a crack, and adhesiveness is the classification | category 3-5.
X: Appearance abnormalities such as swelling, chalking, and cracks are observed.

[Examples 2-7, 10-12, 14, 15 and 17-20, Reference Examples 8 , 9 , 13 and 16 and Comparative Examples 1-12]
Examples 2-7, 10-12, and 14 with the active energy ray-curable ink (ink 1 to ink 5) used, the reaction rate of the curing reaction, and the surface temperature of the cured coating film as the conditions described in Tables 3 to 5 , 15 and 17 to 20, Reference Examples 8 , 9 , 13 and 16 , and the building boards according to Comparative Examples 1 to 12 were produced, and the same evaluation as the building board according to Example 1 was performed. The results are shown in Tables 3-5.

Claims (6)

After coating an active energy ray-curable ink containing a monomer and / or oligomer having an ethylenically unsaturated group on a base material coated with an undercoat, an active energy ray is irradiated to form a cured coating film, Next, it is a manufacturing method of a building board that applies a top coating on the formed cured coating film to manufacture a building board,
The reaction rate of the curing reaction at the time of forming the cured coating film is greater than 90% , and the surface temperature of the cured coating film at the time of applying the top coating is calculated from the formula of Fox. A method for producing a building board, characterized in that the glass transition temperature is higher than a theoretical value.   The method for producing a building board according to claim 1, wherein the active energy ray-curable ink has an average number of functional groups of ethylenically unsaturated groups of 2 or less. The method for producing a building board according to claim 1 or 2 , wherein the surface temperature of the cured coating film when the top coating is applied is 10 ° C or more higher than the theoretical value of the glass transition temperature. Monomer having an ethylenically unsaturated group, isobornyl (meth) acrylate, 2-phenoxyethyl (meth) acrylate, 1,6-hexanediol di (meth) acrylate, and 1,9-nona emissions diol di (meth) acrylate The method for producing a building board according to any one of claims 1 to 3 , wherein the method is one or more selected from the group consisting of: The oligomer having an ethylenically unsaturated group is one or more selected from aliphatic urethane (meth) acrylate, polyester (meth) acrylate, silicone (meth) acrylate, and epoxy (meth) acrylate. The manufacturing method of the building board in any one of Claims 1-4 characterized by the above-mentioned. Paint and / or topcoat of the active energy ray-curable ink, a manufacturing method of building board according to any one of claims 1 to 5, characterized in that an ink jet.