JP5456460B2 - Energy ray curable paint - Google Patents

Description

The present invention relates to curable energy-ray-curable paint by irradiation of energy rays.

    Building materials, structures, and other various molded products typified by floors and walls are generally coated with a paint in order to prevent dirt, protect the base material, and maintain the appearance.

  Conventionally, the solvent type in which synthetic resin is dissolved in a solvent is generally used as a paint, but there are various energy ray curable types using energy ray curable resins in consideration of the work environment and danger to fire. It has been developed and put into practical use in a wide range of fields such as decorative coatings, wood coatings, paper coatings, resist materials, and adhesives.

  Important requirements for such coating applications include stain resistance, resistance to scratches and durability. In order to make it hard to damage, it is common to use means such as increasing the crosslinking density or adding a pigment (Patent Document 1). Various types of paints have been developed to facilitate removal of adhering dirt, such as those using a fluorine-based surface modifier in combination and those having a specific structure in the composition skeleton (Patent Documents 2 and 3). ).

  One of the factors that affect the durability is the water absorption of the paint. If the water absorption is high, the coating tends to crack or peel off.

  Contamination resistance and water absorption can be lowered to some extent by raising the crosslinking density, but there are limits to the crosslinking density alone. In addition, as the crosslinking density increases, there is a tendency that a crack of the coating film is likely to occur due to internal stress.

JP 2009-30047 A JP 2000-34334 A JP-A-8-217840

The present invention has been made in view of the above, and the stain resistance and scratch resistance are further improved, and the water absorption is low, so that the coating film is not easily cracked or peeled off, and a coating film having excellent durability is obtained. providing a resulting energy beam-curable paint for the purpose of.

The energy ray-curable coating material of the present invention comprises a polyether polyol (A) containing a polyether chain portion obtained by ring-opening polymerization of butylene oxide, an organic polyisocyanate (B), and a (meth) acrylate containing a hydroxyl group in the molecule. It is a urethane acrylate obtained by reacting with (C), and contains a urethane acrylate having a double bond content of 1.8 mol / kg or more derived from the (meth) acrylate (C).

Ratio of (A) and component (B) in the above, (A) a polyether polyol Lumpur hydroxyl total moles in (a) and (B) an isocyanate group the total number of moles of organic polyisocyanate in ( It is preferable that the molar ratio with b) is in a range of (a) :( b) = 1.0: 1.1 to 1.0: 4.0.

The energy beam curable coating composition of the present invention has good curability, and the coating film obtained by curing it exhibits good stain resistance and chemical resistance, is hardly scratched, and has low water absorption. The film is hardly cracked or peeled off, and the durability is also good.

  Among the components (A) used in the present invention, examples of polyether polyols containing polyether chain moieties obtained by ring-opening polymerization of butylene oxide include butylene oxide adducts of polyols such as polybutylene glycol and trimethylolpropane. Is mentioned. These polyether polyols (A) preferably have a molecular weight of 200 to 3000, and more preferably 300 to 1500. If the molecular weight is less than 200, the water absorption rate of the cured coating film tends to be high, and if it exceeds 3000, the surface hardness tends to be low and the stain resistance tends to be poor.

  Further, the polytetramethylene ether glycol as the other component (A) preferably has a molecular weight of 200 to 3000, and more preferably 300 to 1500. If the molecular weight is less than 200, the water absorption rate of the cured coating film tends to be high, and if it exceeds 3000, the surface hardness tends to be low and the stain resistance tends to be poor.

  Examples of the organic polyisocyanate (B) include hydrogenated MDI (4,4′-diphenylmethane diisocyanate), isophorone diisocyanate, hexamethylene diisocyanate, xylylene diisocyanate, tolylene diisocyanate and the like. Multiple types can be used in combination. From the viewpoint of weather resistance, hydrogenated MDI or isophorone diisocyanate is used alone or in combination.

  Examples of the hydroxyl group-containing (meth) acrylate (C) include 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, 4-hydroxybutyl acrylate, and caprolactone-modified-2. -Hydroxyethyl acrylate, polyethylene glycol monoacrylate, polypropylene glycol monoacrylate, pentaerythritol triacrylate, dipentaerythritol pentaacrylate and the like can be used, and these can be used alone or in combination. Of these, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate and pentaerythritol triacrylate are preferably used.

  The ratio of the component (A) to the component (B) is the total number of hydroxyl groups (a) of the polyether polyol and / or polytetramethylene ether glycol in (A) and the isocyanate group of the organic polyisocyanate in (B). The molar ratio with respect to the total number of moles (b) is preferably a ratio in the range of (a) :( b) = 1.0: 1.1 to 1.0: 4.0, more preferably 1 The ratio is in the range of 0.0: 1.2 to 1.0: 3.0. If the molar ratio of the component (A) decreases and the weight ratio of the component (A) becomes too small, sufficient contamination resistance and water resistance cannot be expressed, while the molar ratio of the component (A) increases. If the molecular weight is too large, sufficient contamination resistance and water resistance cannot be exhibited.

  Moreover, (C) (meth) acrylate is used in such a ratio that the content of the double bond urethane acrylate derived from the component (C) becomes 1.8 mol / kg or more. If the amount of double bonds is less than this, the surface hardness tends to be low and the stain resistance tends to be poor.

  The urethane acrylate of the present invention can be synthesized by a known method. For example, a predetermined amount of the component (A) and the component (B) are charged all at once and reacted at 70 to 80 ° C. until a predetermined amount of free isocyanate is obtained, and in the presence of a polymerization inhibitor such as hydroquinone monomethyl ether (C ) The components can be charged in a lump and heated and stirred at 70 to 80 ° C. until free isocyanate disappears. At this time, in order to promote the reaction, a tin-based catalyst such as dibutyltin dilaurate may be added.

  The energy ray-curable coating material of the present invention contains the urethane acrylate and can be diluted with an organic solvent or monomers such as ethyl acetate and methyl ethyl ketone. When diluting with a monomer, the content of the urethane acrylate of the present invention is preferably 50% by weight or more.

  As the monomer used for dilution, known and commonly used monomers can be used. Among them, representative examples include 2-ethylhexyl acrylate, styrene, methyl methacrylate, acryloylmorpholine, tetrahydrofurfuryl (meth) acrylate, phenoxyethyl (meth) ) Acrylate, isobornyl (meth) acrylate, ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, 1,4-butanediol-di ( Meth) acrylate, 1,6-hexanediol-di (meth) acrylate, 1,9-nonanediol-di (meth) acrylate, EO (ethylene oxide, the same shall apply hereinafter) modified bisphenol Nord di (meth) acrylate, PO (propylene oxide, the same applies hereinafter) modified bisphenol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, EO modified trimethylolpropane tri (meth) acrylate, PO modified trimethylolpropane tri (meta) ) Acrylate, pentaerythritol tri (meth) acrylate, tris ((meth) acryloxyethyl) isocyanurate, dipentaerythritol hexa (meth) acrylate, dipentaerythritol penta (meth) acrylate and the like. These may be used alone or in combination.

A polymerization initiator by active energy rays is added to the paint of the present invention as required. The polymerization initiator by active energy rays here includes both a photopolymerization initiator and a polymerization initiator by active energy rays such as ultraviolet rays.

  As the photopolymerization initiator, for example, aromatic ketones such as benzophenone, aromatic compounds such as anthracene and α-chloromethylnaphthalene, and sulfur compounds such as diphenyl sulfide and thiocarbamate can be used.

  Examples of the polymerization initiator by active energy rays such as ultraviolet rays other than visible light include acetophenone, acetophenone benzyl ketal, 1-hydroxycyclohexyl phenyl ketone, 2,2-dimethoxy-1,2-diphenylethane-1-one, and xanthone. Fluorenone, benzaldehyde, fluorene, anthraquinone, triphenylamine, carbazole, 3-methylacetophenone, 4-chlorobenzophenone, 4,4'-dimethoxybenzophenone, 4,4'-diaminobenzophenone, benzoin propyl ether, benzoin ethyl ether, benzyl Dimethyl ketal, 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropan-1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one Thioxanthone, diethylthioxanthone, 2-isopropylthioxanthone, 2-chlorothioxanthone, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino-propan-1-one, 2-benzyl-2-dimethylamino-1 -(4-morpholinophenyl) -butanone-1,4- (2-hydroxyethoxy) phenyl- (2-hydroxy-2-propyl) ketone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis- ( 2,6-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide, oligo (2-hydroxy-2-methyl-1- (4- (1-methylvinyl) phenyl) propanone) and the like. it can.

  As a commercial item of the polymerization initiator by active energy rays, for example, trade name: Irgacure 184,369,651,500,819,907,784,2959,1000,1300,1700,1800, manufactured by Ciba Specialty Chemicals, Inc. 1850, Darocur 1116, 1173, manufactured by BASF, Inc. Product name: Lucillin TPO, manufactured by UCB Product name: Ubekril P36, manufactured by Fratteri Lamberti, Inc. Product names: Ezacure KIP150, KIP100F, KT37, KT55, KTO46, TZT, KIP75LT, Japan Product name: Kayacure DETX, etc. manufactured by Kayaku Co., Ltd. can be mentioned.

  If necessary, a radical polymerization initiator can be used in combination with the active energy ray initiator. Examples of the radical polymerization initiator include benzoyl peroxide, methylcyclohexanone peroxide, cumene hydroperoxide, diisopropylbenzene peroxide, di-t-butyl peroxide, t-butyl peroxybenzoate, diisopropyl peroxycarbonate, t- Organic peroxides such as butyl peroxyisopropyl monocarbonate and azo compounds such as 2,2′-azobisisobutyronitrile (AIBN) can be used.

  The content of these polymerization initiators varies depending on the type and the like, but as a guide, it is 1 to 8 parts by weight per 100 parts by weight of urethane acrylate. If the content is too small, the active energy ray sensitivity becomes insufficient. If the content is too large, the active energy rays do not reach the deep part of the coating film, and the curability of the deep part of the coating film tends to be lowered.

Energy-ray-curable coating material of the present invention, the urethane acrylate, an organic solvent or monomers, in addition to various initiators, various additives typically included in the pigment and the coating composition may be added as necessary. Examples of the additive include a light stabilizer, an ultraviolet absorber, a catalyst, a leveling agent, an antifoaming agent, a polymerization accelerator, an antioxidant, a flame retardant, and an infrared absorber.

Incidentally, the energy beam source to cure the energy ray-curable coating material of the present invention is not particularly limited, examples include high-pressure mercury lamp, electron beam, gamma rays, a carbon arc lamp, xenon lamp, metal halide lamp and the like.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples and comparative examples, but the present invention is not limited to these examples. In the following, “part” and “%” are all based on weight unless otherwise specified.

1. Production Example of Polyether Polyol Containing Polyether Chain Part Obtained by Ring-Opening Polymerization of Butylene Oxide [Production of Polybutylene Glycol (Molecular Weight 400)]
1,3-butylene glycol 90 g (1 mol), 1,2-butylene oxide 310 g (4.3 mol) and potassium hydroxide 0.45 g were added to a stainless steel autoclave, and then the inside of the autoclave was purged with nitrogen. Next, the temperature was raised to 120 ° C., the pressure was maintained at 0.1 MPa at this temperature, and the reaction was carried out for 12 hours. After completion of the reaction, unreacted 1,2-butylene oxide was removed under reduced pressure to obtain polybutylene glycol (molecular weight 400).

[Production of polybutylene glycol (molecular weight 1000)]
The reaction was carried out in the same manner as above except that 310 g (4.3 mol) of 1,2-butylene oxide was changed to 910 g (12.6 mol) to obtain polybutylene glycol (molecular weight 1000).

[Production of polybutylene glycol (molecular weight 3000)]
The reaction was conducted in the same manner as above except that 310 g (4.3 mol) of 1,2-butylene oxide was changed to 2910 g (40.3 mol) to obtain polybutylene glycol (molecular weight 1000).

[Production of Butylene Oxide 7-Mole Adduct of Trimethylolpropane]
Except that 90 g (1 mol) of 1,3-butylene glycol was changed to 134.1 g (1 mol) of trimethylolpropane and 310 g (4.3 mol) of 1,2-butylene oxide was changed to 507.7 g (7 mol). The reaction was conducted in the same manner as above to obtain a 7-mole adduct of trimethylolpropane butylene oxide.

2. Synthesis example of urethane acrylate [Synthesis Example 1]
A flask was charged with 638 g (1 mol) of butylene oxide 7-mole adduct of trimethylolpropane (TMP-7BO) and 666 g (3 mol) of isophorone diisocyanate (IPDI), and reacted at 70 to 80 ° C. for about 3 hours. After confirming that the amount of free isocyanate was 9.7 ± 0.3%, 0.8 g of hydroquinone monomethyl ether and 348 g (3.1 mol) of 2-hydroxyethyl acrylate (HEA) were charged, and further 70 to 80 ° C. The urethane acrylate A was obtained by reacting until the amount of free isocyanate was 0.1% or less.

[Synthesis Example 2]
638 g (1 mol) of TMP-7BO is 400 g (1 mol) of polybutylene glycol (PBG-400, molecular weight 400), 348 g (3 mol) of 2-hydroxyethyl acrylate is 255.2 g of pentaerythritol triacrylate (PET-3) (PET-3). The reaction was conducted in the same manner as in Synthesis Example 1 except that 666 g (3 mol) of isophorone diisocyanate (IPDI) was changed to 444 g (2 mol).

[Synthesis Example 3]
Urethane acrylate C was obtained by reacting in the same manner as in Synthesis Example 2 except that 255.2 g (2.2 mol) of pentaerythritol triacrylate was changed to 229.0 g (2.04 mol) of 2-hydroxyethyl acrylate.

[Synthesis Example 4]
Urethane acrylate D was obtained by reacting in the same manner as in Synthesis Example 2 except that 400 g (1 mol) of polybutylene glycol (molecular weight 400) was changed to 1000 g (1 mol) of polybutylene glycol (PBG-1000, molecular weight 1000).

[Comparative Synthesis Example 1]
Urethane acrylate E was obtained by reacting in the same manner as in Synthesis Example 4 except that 255.2 g (2.2 mol) of pentaerythritol triacrylate was changed to 243.6 g (2.1 mol) of 2-hydroxyethyl acrylate.

[Comparative Synthesis Example 2]
1000 g (1 mol) of polybutylene glycol (molecular weight 1000) is added to 3000 g (1 mol) of polybutylene glycol (PBG-3000, molecular weight 3000), and 253.6 g (24 mol) of 2-hydroxyethyl acrylate (2.1 mol) ( Except for the change to 2.2 mol), the reaction was conducted in the same manner as in Comparative Synthesis Example 1 to obtain urethane acrylate F.

[Comparative Synthesis Example 3]
Urethane acrylate G was obtained by reacting in the same manner as in Synthesis Example 3 except that 400 g (1 mol) of polybutylene glycol (molecular weight 400) was changed to 1000 g (1 mol) of polypropylene glycol (molecular weight 1000).

[Comparative Synthesis Example 4]
Urethane acrylate H was obtained in the same manner as in Synthesis Example 3 except that 400 g (1 mol) of polybutylene glycol (molecular weight 400) was changed to 600 g (1 mol) of polyethylene glycol (PEG-600, molecular weight 600).

[Comparative Synthesis Example 5]
Other than changing 400 g (1 mol) of polybutylene glycol (molecular weight 400) to 1500 g (1 mol) of polyethylene glycol (PEG-1500, molecular weight 1500) and 444 g (2 mol) of isophorone diisocyanate to 348 g (2 mol) of tolylene diisocyanate. Was reacted in the same manner as in Synthesis Example 2 to obtain urethane acrylate I.

[Comparative Synthesis Example 6]
Urethane acrylate J was obtained by reacting in the same manner as in Synthesis Example 3, except that 400 g (1 mol) of polybutylene glycol (molecular weight 400) was changed to 1000 g (1 mol) of polytetramethylene glycol (PTMG-1000, molecular weight 1000). .

3. Preparation and evaluation of energy ray curable coating material 3 parts of photopolymerization initiator (Irgacure 184 manufactured by Ciba Specialty Chemicals) for each 100 parts of urethane acrylates A to J obtained in the above synthesis examples and comparative synthesis examples Each was blended and dissolved. This was applied onto a glass plate so as to have a film thickness of about 100 μm, and was cured by irradiation with an integrated illuminance of 200 mJ / cm ² using a high-pressure mercury lamp 80 W / cm. About each obtained hardened | cured material, the stain resistance, chemical resistance, the water absorption rate, and pencil hardness were investigated with the following method. The results are shown in Table 1.

Contamination resistance: Evaluated according to JIS K5400. That is, the contaminants shown in the table were placed on the cured coating film and left at room temperature for about 18 hours. Wipe with water or wipe with isopropyl alcohol, and observe visually after wiping. X indicates that the contaminant remains in the coating or changes in the coating, and the coating has changes but is minor. △, and those where no contaminants remained and the coating film remained unchanged were marked with ◯.

Chemical resistance: Evaluated according to JIS K5400. That is, several drops of the chemicals shown in the table were placed on the cured coating film and allowed to stand at room temperature for about 18 hours. After rinsing with water, the coating film was visually observed. The change was observed as x, the change was slight but slight, and the coating film was unchanged as O.

Water absorption: The cured coating film was peeled off from the glass plate and immersed in distilled water (23 ° C.) for 24 hours. It calculated | required based on following Formula from the weight (A) measured immediately after wiping off the surface water, and the weight (B) measured after drying in 105 degreeC oven for 3 hours.

      Water absorption (%) = {(A−B) / B} × 100

Pencil hardness: According to JIS K5400, it was scratched with a pencil scratch tester under a load of 1 kg, and the hardness of the hardest pencil without scratches was obtained. ("<6B" in the table indicates a hardness that is softer than "6B".)

The energy ray curable coating composition of the present invention can be suitably used for various building materials, structures, and moldings.

Claims (3)

Obtained by reacting a polyether polyol (A) containing a polyether chain moiety obtained by ring-opening polymerization of butylene oxide, an organic polyisocyanate (B), and a (meth) acrylate (C) containing a hydroxyl group in the molecule. Urethane acrylate,
An energy ray-curable coating material containing urethane acrylate having a content of double bonds derived from the (meth) acrylate (C) of 1.8 mol / kg or more. The ratio of the component (A) to the component (B)
The molar ratio of the total number of moles of hydroxyl groups (a) of the polyether polyol in (A) to the total number of moles (b) of isocyanate groups in the organic polyisocyanate in (B) is (a) :( b) = 1.0. The energy ray-curable coating material according to claim 1, wherein the ratio is in a range of 1.1 to 1.0: 4.0. The energy ray-curable coating material according to claim 1 or 2, wherein a content of a polyether chain portion obtained by ring-opening polymerization of butylene oxide in the urethane acrylate is 22% by weight or more.