Coating composition and hydrophilic member
阅读说明：本技术 涂料组合物及亲水性构件 (Coating composition and hydrophilic member ) 是由 加藤大贵 植村真利子 小林信幸 三木慎一郎 于 2018-11-27 设计创作，主要内容包括：本发明的涂料组合物含有：1分子中具有氧化乙烯基的重复单元和2官能的(甲基)丙烯酰基的第一单体；和1分子中具有3官能以上的(甲基)丙烯酰基和1官能以上的羟基的第二单体。另外,第一单体中的氧化乙烯基的重复单元的数量为18～40。进而,在将第一单体和第二单体的含量合计设为100质量％时,第一单体的含量为40质量％～95质量％,第二单体的含量为5质量％～60质量％。第一单体相对于固体成分整体的含量为40质量％～85质量％,第二单体相对于固体成分整体的含量为10质量％～55质量％。(The coating composition of the present invention comprises: 1 a first monomer having a repeating unit of an oxyethylene group and a 2-functional (meth) acryloyl group in a molecule; and 1 a second monomer having a (meth) acryloyl group having 3 or more functions and a hydroxyl group having 1 or more functions in the molecule. The number of repeating units of an oxyethylene group in the first monomer is 18 to 40. Further, when the total content of the first monomer and the second monomer is 100% by mass, the content of the first monomer is 40% by mass to 95% by mass, and the content of the second monomer is 5% by mass to 60% by mass. The content of the first monomer is 40 to 85 mass% based on the whole solid content, and the content of the second monomer is 10 to 55 mass% based on the whole solid content.)
1. A coating composition comprising:
1 a first monomer having a repeating unit of an oxyethylene group and a 2-functional (meth) acryloyl group in a molecule; and
1 (meth) acryloyl group having 3 or more functions and a hydroxyl group having 1 or more functions in a molecule,
the number of repeating units of the oxyethylene group in the first monomer is 18 to 40,
wherein the content of the first monomer is 40 to 95% by mass and the content of the second monomer is 5 to 60% by mass, when the total content of the first monomer and the second monomer is 100% by mass,
the content of the first monomer relative to the whole solid content is 40-85% by mass,
the content of the second monomer is 10 to 55 mass% with respect to the entire solid content.
2. The coating composition according to claim 1, wherein the first monomer is a di (meth) acrylate monomer having the (meth) acryloyl group at each end of a main chain of the repeating unit containing the oxyethylene group.
3. The coating composition according to claim 1 or 2, further comprising a (meth) acrylate having a polysiloxane.
4. A hydrophilic member is provided with:
a substrate; and
a hydrophilic film disposed on the substrate and formed from the coating composition of any one of claims 1 to 3.
Technical Field
The present invention relates to a coating composition and a hydrophilic member. More specifically, the present invention relates to a coating composition and a hydrophilic member capable of forming a coating film having antifogging properties.
Background
For example, in the case of a mirror for a washbasin or the like, when the surface temperature of the mirror is lowered in winter, dew condensation may occur on the surface of the mirror due to water vapor in the air, and the mirror may be fogged. In order to eliminate such fog, various methods have been proposed.
For example, patent document 1 describes that a hard coat layer or a cured coating film having excellent electrostatic properties and antifogging properties is formed by applying a composition to the surface of a synthetic resin molded article and then curing the composition.
The composition of patent document 1 is described to contain a polyfunctional monomer (a) having 3 or more (meth) acryloyl groups and a monofunctional or difunctional monomer (B). Examples of the monomer (B) include polyethylene glycol mono (meth) acrylate, polyoxyethylene glycol mono (meth) acrylate, polyethylene glycol (meth) acrylate, and polypropylene glycol di (meth) acrylate.
It is also described that the composition of the example in patent document 1 contains 25 parts by mass of PE-4A and 30 parts by mass of PE-3A as the monomer (a), and 15 parts by mass of a predetermined polyethylene glycol diacrylate as the monomer (B). Furthermore, PE-4A is pentaerythritol tetraacrylate and PE-3A is pentaerythritol triacrylate.
Disclosure of Invention
According to patent document 1, the cured coating film obtained from the above composition is excellent in all of scratch resistance, abrasion resistance, electrostatic properties and antifogging properties. However, since a coating film having a higher antifogging property is demanded in the market, even the above-mentioned composition cannot be said to have a sufficient antifogging property, and a coating composition capable of forming a coating film having a further excellent antifogging property is demanded.
The present invention has been made in view of the problems of the prior art. Further, an object of the present invention is to provide a coating composition and a hydrophilic member capable of forming a coating film having excellent antifogging properties.
In order to solve the above problems, a coating composition according to a first aspect of the present invention includes: 1 a first monomer having a repeating unit of an oxyethylene group and a 2-functional (meth) acryloyl group in a molecule; and 1 a second monomer having a (meth) acryloyl group having 3 or more functions and a hydroxyl group having 1 or more functions in the molecule. The number of repeating units of an oxyethylene group in the first monomer is 18 to 40. Further, when the total content of the first monomer and the second monomer is 100% by mass, the content of the first monomer is 40% by mass to 95% by mass, and the content of the second monomer is 5% by mass to 60% by mass. The content of the first monomer is 40 to 85 mass% based on the whole solid content, and the content of the second monomer is 10 to 55 mass% based on the whole solid content.
A hydrophilic member according to a second aspect of the present invention includes: a substrate, and a hydrophilic film disposed on the substrate and formed from the above coating composition.
Detailed Description
[ coating composition ]
Example 3 of patent document 1 describes a composition comprising 25 parts by weight of PE-4A, 30 parts by weight of PE-3A, 25 parts by weight of NVP, 15 parts by weight of 45EO-DA, 20 parts by weight of EC and 5 parts by weight of HCHPK. Here, PE-4A is pentaerythritol tetraacrylate, PE-3A is pentaerythritol triacrylate and NVP is N-vinyl-2-pyrrolidone. In addition, 45EO-DA uses polyethylene glycol diacrylate having a number of repeating units of oxyethylene group of 45. EC is ethyl cellosolve and is used as a non-polymerizable solvent, HCHPK is 1-hydroxycyclohexyl phenyl ketone and is used as a photopolymerization initiator.
According to patent document 1, the cured coating film obtained from the above composition is excellent in all of scratch resistance, abrasion resistance, electrostatic properties and antifogging properties.
However, since a coating film having a higher antifogging property is demanded in the market, even the above-mentioned composition cannot be said to have a sufficient antifogging property, and a coating composition capable of forming a coating film having a further excellent antifogging property is demanded.
Here, as one of means for improving the antifogging property of the coating film, it is conceivable to increase the number of repeating units of an oxyethylene group as a hydrophilic group. However, as described in patent document 1, if the number of repeating units of the oxyethylene group is excessively increased, not only the antifogging property of the coating film is rather decreased, but also the electrostatic property, the abrasion resistance and the wear resistance may be decreased.
In addition, it is conceivable to increase the content of polyethylene glycol diacrylate such as 45EO-DA in order to improve the antifogging property of the coating film. Here, patent document 1 describes: the content of the monomer (B) in the composition is preferably set in the range of 5 to 30 parts by weight based on 100 parts by weight of the composition, from the viewpoint of imparting excellent antifogging property to the cured coating film.
However, even if the content of polyethylene glycol diacrylate such as 45EO-DA is increased to about 30 parts by mass, sufficient antifogging property may not be obtained. When the content of the polyethylene glycol diacrylate such as 45EO-DA exceeds 30 parts by mass, the hardness and water resistance of the coating film may be lowered. In example 3 of patent document 1, PE-4A and PE-3A are considered to correspond to the monomer (A). In example 3 of patent document 1, it is considered that 45EO-DA corresponds to the monomer (B). Therefore, in example 3, the content of the monomer (B) is considered to be about 21 mass% when the total content of the monomer (a) and the monomer (B) is 100 mass%. When the content of the monomer (B) in example 3 is only 30 parts by mass, the content of the monomer (B) is considered to be about 35% by mass when the total content of the monomer (a) and the monomer (B) is 100% by mass.
Accordingly, the coating composition of the present embodiment contains 1 first monomer having a repeating unit of an oxyethylene group and a (meth) acryloyl group having 2 or more functions in a molecule. The coating composition of the present embodiment contains a second monomer having a (meth) acryloyl group having 3 or more functions and a hydroxyl group having 1 or more functions in 1 molecule. The number of repeating units of an oxyethylene group in the first monomer is 18 to 40. Further, when the total content of the first monomer and the second monomer is 100% by mass, the content of the first monomer is 40% by mass to 95% by mass, and the content of the second monomer is 5% by mass to 60% by mass.
The coating composition contains a first monomer that mainly imparts antifogging properties to the coating film and a second monomer that mainly imparts hardness and water resistance to the coating film. Further, the number of repeating units of an oxyethylene group in the first monomer is within a predetermined range, and the contents of the first monomer and the second monomer are within a predetermined range. Therefore, the coating composition of the present embodiment can form a coating film excellent in antifogging property, hardness and water resistance by being applied to a substrate and cured. Each constituent element will be described in detail below.
(first monomer)
The coating composition of the present embodiment contains a first monomer having 1 repeating unit having an oxyethylene group and 2 or more functional (meth) acryloyl groups in a molecule. That is, the first monomer has a repeating unit of an oxyethylene group contributing to antifogging property and a 2-functional or higher (meth) acryloyl group contributing to hardness and water resistance of the coating film by polymerization.
The first monomer can impart antifogging properties to the coating film by containing a repeating unit of an oxyethylene group having hydrophilicity. In addition, since the first monomer of the present embodiment has a repeating unit of an oxyethylene group in 1 molecule, the influence of bleeding or a decrease in function with time can be reduced as compared with the case where an additive such as an antistatic agent is added to impart an antifogging property to a film.
- (CH) for ethylene oxide group2CH2And O) -is represented by the structural unit. Further, the first monomer has oxidation in 1 moleculeVinyl radical (CH)2CH2O) repeating units. Specifically, the number of repeating units of an oxyethylene group in the first monomer is 18 to 40. When the number of repeating units of an oxyethylene group is 18 or more, the chemical structure having hydrophilicity in the coating film increases, and therefore, water vapor which causes dew condensation can be absorbed. Therefore, the irregular reflection due to dew condensation can be suppressed, and the antifogging property of the coating film can be improved. Further, by setting the number of repeating units to 40 or less, the hardness and water resistance of the coating film can be improved. From the viewpoint of antifogging properties, the number of repeating units of an oxyethylene group is preferably 20 or more, more preferably 22 or more, and still more preferably 23 or more. From the viewpoint of hardness and water resistance, the number of repeating units of an oxyethylene group is preferably 38 or less, more preferably 36 or less, and still more preferably 35 or less. Further, the repeating unit of the oxyethylene group may be continuously repeated within 1 molecule, or may be discontinuously and intermittently repeated. The first monomer may be used alone in 1 kind or in combination of two or more kinds. In addition, in the present specification, the number of repeating units of oxyethylene group is the number average molecular weight M of the first monomernThe molecular weight of the chemical structure other than the oxyethylene group is subtracted, and then divided by the molecular weight of the oxyethylene group, and the obtained value is rounded to the obtained integer.
In the first monomer, due to the weight average molecular weight MwHas the number average molecular weight MnThe above tendency, therefore, the weight average molecular weight MwAnd number average molecular weight MnRatio of (M)w/Mn) Generally 1 or more. In addition, M in the first monomerw/MnThe value of (b) is preferably 1.4 or less, more preferably 1.1 or less. In the present specification, the weight average molecular weight MwAnd number average molecular weight MnThe measurement can be carried out by Gel Permeation Chromatography (GPC) and can be determined using polyethylene glycol as a standard sample. In addition, when the molecular weight distribution of the first monomer has a plurality of peaks, the weight average molecular weight M in each peak can be determinedwAnd number average molecular weight Mn。
The first monomer has in 1 moleculeA (meth) acryloyl group having 2 or more functions. (meth) acryloyl with-OCOCH ═ CH2or-OCOC (CH)3)＝CH2Meaning that the polymer may be formed by a polymerization reaction. When the (meth) acryloyl group in 1 molecule is 2 or more functional, the crosslinking density of the polymer forming the coating film can be increased as compared with the case where the (meth) acryloyl group is 1 functional. Therefore, the water resistance of the coating film can be improved.
The (meth) acryloyl group of the first monomer includes 2-functional, 3-functional, and 4-or more-functional groups. However, from the viewpoint of antifogging property, the (meth) acryloyl group contained in the first monomer is preferably at least one of 2-functional and 3-functional, and more preferably 2-functional. That is, the first monomer is more preferably di (meth) acrylate. The (meth) acryloyl group in the first monomer includes a methacryloyl group and an acryloyl group, and is preferably an acryloyl group from the viewpoint of curing speed.
The first monomer is preferably a monomer having a (meth) acryloyl group at each end of the main chain of the repeating unit containing an oxyethylene group. Further, the oxyethylene group having the number of repeating units of 18 to 40 is preferably contained in the main chain of the first monomer. When such a first monomer is used in a coating composition, a coating film having excellent water resistance can be formed. The first monomer may be at least 1 monomer selected from the group consisting of polyethylene glycol di (meth) acrylate represented by the following chemical formula (1), ethylene oxide-modified bisphenol a di (meth) acrylate represented by the following chemical formula (2), ethylene oxide-modified bisphenol F di (meth) acrylate represented by the following chemical formula (3), ethylene oxide-modified hexanediol di (meth) acrylate represented by the following chemical formula (4), and ethylene oxide-modified neopentyl glycol di (meth) acrylate represented by the following chemical formula (5).
[ chemical formula No. 1]
[ chemical formula No. 2]
[ chemical formula No. 3]
[ chemical formula No. 4]
[ chemical formula No. 5]
In the above chemical formulas (1) to (5), R is1And R2Are each H or CH3L is an integer of 18 to 40, and m + n is an integer of 18 to 40.
In addition, the chemical formula (1) - (5) monomer can be used alone 1, also can be combined with 2 or more. In addition, from the viewpoint of antifogging property, the first monomer preferably contains polyethylene glycol di (meth) acrylate represented by the above chemical formula (1).
In order to increase the rigidity of the coating film, the first monomer preferably contains a (meth) acrylate having a bisphenol skeleton as shown in the above chemical formula (2) and chemical formula (3). From the viewpoint of antifogging property and rigidity, the first monomer preferably contains polyethylene glycol di (meth) acrylate represented by the above chemical formula (1) and (meth) acrylate having a bisphenol skeleton. Specifically, the first monomer preferably further contains at least one of polyethylene glycol di (meth) acrylate represented by the above chemical formula (1), ethylene oxide-modified bisphenol a di (meth) acrylate represented by the above chemical formula (2), and ethylene oxide-modified bisphenol F di (meth) acrylate represented by the above chemical formula (3). In addition, the first monomer preferably contains polyethylene glycol di (meth) acrylate represented by the above chemical formula (1) and ethylene oxide-modified bisphenol a di (meth) acrylate represented by the above chemical formula (2).
As a specific example of the first monomer, NK-Ester A-1000 (polyethylene glycol #1000 diacrylate: R in the above chemical formula (1): R in chemical formula (1)) from shinkamura chemical industries, Ltd1＝H，R2H and l 23), NK-Ester a-BPE-20(EO (ethylene oxide) -modified bisphenol a diacrylate: in the above chemical formula (2), R1＝H，R2H and m + n 20)), and the like.
The weight average molecular weight of the first monomer is preferably 800 to 3000g/mol, more preferably 850 to 2300 g/mol. By making the weight average molecular weight of the first monomer in such a range, the coating characteristics of the coating composition can be improved.
The content of the first monomer is preferably 35 to 95% by mass, and more preferably 40 to 85% by mass, based on the entire solid content of the coating composition. When the content of the first monomer is in the above range, a coating composition capable of improving antifogging property, water resistance and hardness of a coating film can be provided.
(second monomer)
The second monomer has a (meth) acryloyl group having 3 or more functions and a hydroxyl group having 1 or more functions in 1 molecule. That is, the second monomer has a 3-or more-functional (meth) acryloyl group that contributes to the hardness and water resistance of the coating film through a polymerization reaction. The second monomer has a 1-functional or higher hydroxyl group which contributes to antifogging property of the coating film, suppresses reaction inhibition as a hydrogen donor, and contributes to improvement of hardness of the coating film.
The second monomer has a (meth) acryloyl group having 3 or more functions in 1 molecule. Therefore, the polymer formed by the polymerization reaction forms a three-dimensional mesh structure, whereby the hardness and water resistance of the coating film can be improved as compared with the case where the polymer has a (meth) acryloyl group having a bifunctional or less. The (meth) acryloyl group in the second monomer includes a methacryloyl group and an acryloyl group, and is preferably an acryloyl group from the viewpoint of curing speed.
The (meth) acryloyl group in the second monomer may be 3-functional or 4-or more-functional. However, from the viewpoint of suppressing curing shrinkage, it is preferable that the second monomer has a 3-functional (meth) acryloyl group in 1 molecule.
The hydroxyl group in the second monomer is not particularly limited as long as it has a hydroxyl group having 1 or more functions. However, the hydroxyl group in the second monomer is preferably 1 functional.
Specifically, the second monomer more preferably has a 3-functional (meth) acryloyl group and a 1-functional hydroxyl group in 1 molecule. By using such a second monomer, a coating composition capable of forming a coating film excellent in antifogging property, hardness and water resistance can be obtained.
Examples of the second monomer include pentaerythritol tri (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, and ditrimethylolpropane tri (meth) acrylate. These monomers may be used alone in 1 kind, and may also be used in combination of 2 or more kinds. Among them, pentaerythritol tri (meth) acrylate is preferably used from the viewpoint of coating properties. Further, as the second monomer, NEW front (registered trademark) PET-3 (pentaerythritol triacrylate) manufactured by first industrial pharmaceutical co.
The weight average molecular weight of the second monomer is not particularly limited, but is preferably 230 to 800g/mol, more preferably 260 to 600g/mol, and still more preferably 200 to 400 g/mol. By making the weight average molecular weight of the second monomer in such a range, the coating characteristics of the coating composition can be improved.
The content of the second monomer is preferably 4 to 60% by mass, more preferably 10 to 55% by mass, based on the entire solid content of the coating composition. When the content of the second monomer is in the above range, a coating composition capable of improving antifogging property, water resistance and hardness of a coating film can be provided.
In the present embodiment, when the total content of the first monomer and the second monomer is 100% by mass, the content of the first monomer is 40% by mass to 95% by mass, and the content of the second monomer is 5% by mass to 60% by mass. When the contents of the first monomer and the second monomer are in the above ranges, a coating composition capable of improving antifogging property, water resistance and hardness of a coating film can be provided. When the total content of the first monomer and the second monomer is 100% by mass, the content of the first monomer is more preferably 45% by mass to 85% by mass and the content of the second monomer is more preferably 15% by mass to 55% by mass. When the total content of the first monomer and the second monomer is 100% by mass, the content of the first monomer is more preferably 50% by mass to 80% by mass and the content of the second monomer is more preferably 20% by mass to 50% by mass. The total content of the first monomer and the second monomer relative to the entire solid content of the coating composition is preferably 70% by mass or more, more preferably 80% by mass or more, still more preferably 90% by mass or more, and particularly preferably 95% by mass or more. The total content of the first monomer and the second monomer with respect to the entire solid content of the coating composition is preferably less than 100% by mass.
The coating composition of the present embodiment may further contain a third monomer other than the first monomer and the second monomer in addition to the first monomer and the second monomer within a range not to impair the effects of the present embodiment. Examples of the third monomer include styrene monomers, olefin monomers, vinyl monomers, and acrylic monomers. Examples of the styrene monomer include styrene. Examples of the olefin monomer include ethylene and propylene. Examples of the vinyl monomer include vinyl chloride and vinylidene chloride. Examples of the acrylic monomer include (meth) acrylate esters. Furthermore, (meth) acrylates include acrylates and methacrylates. The above-mentioned monomer components may be used alone in 1 kind, or may be used in combination in 2 or more kinds. The content of the third monomer in the coating composition is not particularly limited, and is preferably 0.001 to 25% by mass, more preferably 0.005 to 15% by mass, based on the whole solid content of the coating composition.
The third monomer preferably contains a (meth) acrylate having at least one of fluorine and polysiloxane in 1 molecule. These (meth) acrylates tend to concentrate on the surface after application of the coating composition. In addition, since these (meth) acrylates can reduce the surface tension of the coating film itself, the surface of the coating film has water repellency and oil repellency. As described above, the coating composition of the present embodiment has water absorption property because it has the hydrophilic first monomer. On the other hand, a coating composition containing a (meth) acrylate having at least one of fluorine and polysiloxane in 1 molecule, when cured, has water repellency and oil repellency on the surface of the coating film. Therefore, even when the amount of water exceeds the amount of water absorbed by the first monomer or the like, the water droplets on the surface of the coating film are made hydrophobic by the hydrophobic effect of the monomer, and the antifogging property of the coating film can be improved. Further, a coating film obtained by curing a coating composition containing a (meth) acrylate having at least one of fluorine and polysiloxane also has oil repellency. Therefore, by adding a (meth) acrylate having at least either one of fluorine and polysiloxane to the coating composition, not only antifogging properties but also antifouling properties can be imparted to the coating film.
The amount of the (meth) acrylate having at least one of fluorine and polysiloxane in 1 molecule is not particularly limited as long as the effects of the present embodiment are not impaired. In addition, the (meth) acrylate having at least one of fluorine and polysiloxane in 1 molecule can exhibit the above-described water repellency and oil repellency in a small amount. Therefore, the content of the (meth) acrylate having at least one of fluorine and polysiloxane in 1 molecule is preferably 0.001 to 5% by mass, more preferably 0.005 to 1% by mass, based on the whole solid content of the coating composition.
Examples of the (meth) acrylate having fluorine in 1 molecule include trifluoromethyl (meth) acrylate, trifluoroethyl (meth) acrylate, perfluorodecyl ethyl (meth) acrylate, perfluorooctyl ethyl (meth) acrylate, perfluorohexyl ethyl (meth) acrylate, perfluorobutyl ethyl (meth) acrylate, perfluoropolyether (meth) acrylate, and the like.
When a (meth) acrylate having a polysiloxane is used as the third monomer, the surface properties of the coating film, such as slipperiness and smoothness, can be modified. Therefore, the coating composition of the present embodiment preferably further contains a (meth) acrylate having a polysiloxane. For example, the lubricity of the surface of the coating film can be improved by imparting slip properties to the surface of the coating film, and thus indices such as pencil hardness can be improved. Further, by giving a smooth feeling to the surface of the coating film, the touch feeling on the surface of the coating film can be improved.
Examples of the (meth) acrylate having a polysiloxane in 1 molecule include (meth) acrylates obtained by modifying a structure having a polysiloxane as a main skeleton, such as polydimethylsiloxane, polydiethylsiloxane, polydiphenylsiloxane, and polymethylphenylsiloxane, with a (meth) acrylate. Further, as a specific example of the (meth) acrylate having a polysiloxane in 1 molecule, for example, Xinyu Silicone (registered trademark) X-22-174ASX (methacrylate ester having polydimethylsiloxane (methacrylic acid-modified Silicone oil)) and the like of Xinyu chemical industry Co.
The coating composition of the present embodiment preferably contains a polymerization initiator for promoting a polymerization reaction of the first monomer and the second monomer having a carbon-carbon unsaturated bond. The content of the polymerization initiator is not particularly limited, and is preferably 1 to 10% by mass based on the whole solid content of the coating composition. As the polymerization initiator, at least one of a photopolymerization initiator and a thermal polymerization initiator can be used, and a photopolymerization initiator is preferably used. By using a photopolymerization initiator, the first monomer and the second monomer are instantaneously cured by irradiation with active energy rays, and thus the production process can be shortened.
The photopolymerization initiator is a compound having a function of initiating a polymerization reaction of the first monomer and the second monomer, and is a substance that absorbs light of a specific wavelength from active energy rays, changes to an excited state, and generates radicals or ions. As such a photopolymerization initiator, for example, at least 1 selected from benzoin ether systems, ketal systems, acetophenone systems, benzophenone, and thioxanthone systems can be used. As a specific example of the photopolymerization initiator, Irgacure (registered trademark) 184 (1-hydroxycyclohexyl phenyl ketone (acetophenone type)) from BASF corporation, for example, can be used.
The thermal polymerization initiator is a compound having a function of initiating a polymerization reaction of the first monomer and the second monomer, and generates an active species such as a radical or an ion by heating. As the thermal polymerization initiator, at least 1 selected from azo compounds such as 2, 2' -azobis (isobutyronitrile), peroxides such as benzoyl peroxide, benzene sulfonate, and alkyl sulfonium salts can be used.
The coating composition of the present embodiment may further contain additives having various functions within a range not to impair the effects of the present embodiment. As the additives, surfactants, surface property modifiers, durability improvers, colorants, ultraviolet absorbers, light stabilizers, and the like can be used. These additives may be used alone in 1 kind, or may be used in combination in 2 or more kinds.
The surfactant may be added for the purpose of improving leveling property and defoaming property of the coating composition and hydrophilizing the surface of the coating film. The surfactant is not particularly limited, and may be selected according to the intended use. The surfactant may be chemically bonded to the first monomer or the second monomer to exhibit the above-described effect, or may be present in a polymer of the first monomer and the second monomer without being chemically bonded to each other.
The surface property modifier may be added to the coating composition for the purpose of improving the surface properties such as touch. The surface property modifier may be added, for example, with a silicone monomer, a fluorine-based monomer, or the like. The surface texture modifier can chemically bond to the first monomer or the second monomer, for example, to exhibit the above-described effects of the coating film.
The durability improving agent may be added to the coating composition in order to improve durability against chemicals, heat, sliding, and the like. As the durability improver, for example, a material having a rigid chemical structure such as a benzene ring or a bisphenol structure, or a flexible chemical structure such as paraffin can be used.
Next, a method for producing the coating composition of the present embodiment will be described. The coating composition can be prepared by mixing the first monomer and the second monomer, and additives added as needed. The mixing conditions are not particularly limited, and the mixing may be carried out in the air at normal temperature. The mixing order of the first monomer, the second monomer and the additive is not particularly limited.
When the first monomer and the second monomer are mixed, a dispersion solvent is preferably added to the coating composition to adjust the viscosity so that the coating composition can be easily applied. As the dispersion solvent for viscosity adjustment, at least one of water and an organic solvent can be used. The organic solvent is not particularly limited, and is preferably appropriately selected so as to be easily volatilized at the time of coating film formation and so as not to cause curing inhibition or the like at the time of coating film formation. Examples of the organic solvent include aromatic hydrocarbons (e.g., toluene and xylene), alcohols (e.g., methanol, ethanol, and isopropanol), and ketones (e.g., acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone). Further, aliphatic hydrocarbons (hexane, heptane and the like), ethers (tetrahydrofuran and the like), amide solvents (N, N-Dimethylformamide (DMF), dimethylacetamide (DMAc) and the like), methyl acetate and butyl acetate may be mentioned. These organic solvents may be used alone in 1 kind, or may be used in combination in 2 or more kinds. The amount of the dispersion solvent to be added is not particularly limited, and may be, for example, 0.1 to 500 parts by mass per 100 parts by mass of the coating composition.
As described above, the coating composition of the present embodiment contains the first monomer having 1 repeating unit having an oxyethylene group and 2 or more functional (meth) acryloyl groups in a molecule. The coating composition of the present embodiment contains a second monomer having a (meth) acryloyl group having 3 or more functions and a hydroxyl group having 1 or more functions in 1 molecule. The number of repeating units of an oxyethylene group in the first monomer is 18 to 40. Further, when the total content of the first monomer and the second monomer is 100% by mass, the content of the first monomer is 40% by mass to 95% by mass, and the content of the second monomer is 5% by mass to 60% by mass.
As described above, the coating composition of the present embodiment contains the first monomer that mainly imparts antifogging properties to the coating film and the second monomer that mainly imparts hardness and water resistance to the coating film. In the present embodiment, the number of repeating units of an oxyethylene group in the first monomer and the contents of the first monomer and the second monomer are set to predetermined ranges. Therefore, according to the coating composition of the present embodiment, a coating film having excellent hardness and water resistance can be formed while improving the antifogging property of the coating film formed from the coating composition. Therefore, the coating composition of the present embodiment can form a coating film excellent in antifogging property, hardness, and water resistance.
Further, since the coating film obtained from the coating composition has high hydrophilicity, it is also possible to float oil stains with a large amount of water and easily remove the oil stains. Therefore, the coating composition of the present embodiment can improve the oil stain resistance.
The coating composition of the present embodiment has antifogging properties, and therefore can be applied to members such as housing members, vehicle members, crime prevention members, and the like. Examples of the member used for these include mirrors, window glasses, lenses, displays, and the like. Further, the coating film formed using the coating composition of the present embodiment has a hydrophilic property, and therefore has an oil stain-proofing property. Therefore, the present invention can be applied to a housing member such as a kitchen member. In addition, the present invention can also be applied to a sirocco fan or a propeller fan installed in a range hood in a kitchen.
[ hydrophilic Member ]
Next, the hydrophilic member of the present embodiment will be described. The hydrophilic member of the present embodiment includes a substrate and a hydrophilic film provided on the substrate and formed from the coating composition. That is, the hydrophilic member of the present embodiment forms a hydrophilic film (coating film) having hydrophilicity by applying the coating composition to a substrate and curing the coating composition.
The substrate is not particularly limited, and at least one of an inorganic substrate made of an inorganic material and an organic substrate made of an organic material may be used. Examples of the inorganic substrate include ceramics such as aluminum, iron, stainless steel, galvanized steel sheet, glass, enamel, ceramics such as ceramics, slates, and alumina. Examples of the organic base material include plastic materials and sheets such as polycarbonate, acrylic resin, ABS resin (acrylonitrile-butadiene-styrene resin), vinyl chloride resin, epoxy resin, polyester resin, and fiber-reinforced plastic. Examples of the fiber-reinforced plastic include carbon fiber-reinforced plastic, glass fiber-reinforced plastic, and SMC (sheet molding compound).
In addition, a substrate obtained by coating an organic coating film on the inorganic substrate or organic substrate may be used. Examples of the organic coating include acrylic, polyester, urethane, epoxy, melamine, silicone, and fluorine-based coatings. In order to improve the adhesion between these coatings and the substrate, the substrate may be subjected to surface treatment such as solvent degreasing, alkali degreasing, and polishing, or an acrylic, epoxy, or silicone primer may be applied to the substrate as a primer layer.
The hydrophilic film may be formed by curing the above coating composition. The hydrophilic film is formed of a polymer of a first monomer and a second monomer.
The thickness of the hydrophilic film in the hydrophilic member is not particularly limited, and is, for example, preferably 1 to 100 μm, and more preferably 10 to 80 μm. When the thickness of the hydrophilic film is within this range, the hardness and water resistance can be improved. Further, the hydrophilic film having a thickness of 100 μm or less can be strongly bonded to the substrate to suppress peeling.
In the hydrophilic member, the contact angle of water on the surface of the hydrophilic film is preferably 20 ° or less, more preferably 10 ° or less. When the contact angle of water on the surface of the hydrophilic film is 20 ° or less, the hydrophilic film has high hydrophilicity. Therefore, the antifogging property can be improved, or the oil adhered to the surface of the hydrophilic film can be easily removed. The contact angle of water can be measured by a sessile drop method.
Next, a method for producing the hydrophilic member according to the present embodiment will be described. First, the surface of the substrate is washed to remove the stains on the surface. The washing method is not particularly limited, and a known method can be used.
Next, the above coating composition is applied on the surface of the washed substrate. In this case, the method of applying the coating composition is not particularly limited. As a method of applying the coating composition to the main surface of the substrate, a coating method or a printing method may be used. In the coating method, the coating composition can be applied using air spray, brush, bar coater, wire bar, air knife, or the like. Further, the coating composition may be applied by a spin coating method. In the printing method, a method such as gravure printing, reverse gravure printing, offset printing, flexographic printing, screen printing, or the like can be used.
After the coating composition is applied to the surface of the substrate, the dispersion solvent in the coating composition may be removed by drying treatment as needed. The drying conditions are not particularly limited as long as the dispersion solvent is removed, and the drying conditions may be heat-treated as necessary.
When a photopolymerization initiator is used as the polymerization initiator, the coating composition is applied to the surface of the substrate, and then irradiated with active energy rays to cure the coating composition. As the active energy ray to be irradiated when curing the coating composition, at least any one of ultraviolet ray, electron beam, X-ray, infrared ray and visible ray can be used. Among these active energy rays, ultraviolet rays or electron beams are preferably used from the viewpoint of curability and prevention of deterioration of the resin.
When the coating composition is cured by ultraviolet irradiation, various ultraviolet irradiation apparatuses can be used. As the ultraviolet irradiation device, a xenon lamp, a high-pressure mercury lamp, a metal halide lamp, or the like can be used. Further, the dose of the ultraviolet ray irradiation is usually 10 to 10000mJ/cm2. However, from the viewpoint of improving the curability of the composition, the dose of ultraviolet irradiation is preferably 100mJ/cm2The above. In addition, it is preferable that the ultraviolet rays are irradiated under a nitrogen atmosphere so as not to inhibit curing by oxygen in the air.
When a thermal polymerization initiator is used as the polymerization initiator, the coating composition is cured by applying the coating composition to the surface of the substrate and then heating the coating composition. The heating condition is not particularly limited, and may be a temperature at which the thermal polymerization initiator used is decomposed to generate active species.
As described above, the hydrophilic member of the present embodiment can be produced by applying the coating composition to a substrate and then curing the coating composition. Therefore, a hydrophilic member having high hydrophilicity can be obtained by a simple method.
As described above, the hydrophilic member of the present embodiment includes a substrate and a hydrophilic film provided on the substrate and formed of the coating composition. The hydrophilic film has high antifogging property, hardness and water resistance. Further, since the hydrophilic film has high hydrophilicity, even when oil such as oil stain adheres to the hydrophilic film, water can enter between the surface of the hydrophilic film and the oil by contacting the hydrophilic member with water. Further, since the oil component floats from the hydrophilic membrane by the water intrusion, the oil component can be easily removed.
Examples of the hydrophilic member include members for houses, members for vehicles, crime prevention members, and the like. Specifically, a mirror, a window glass, a lens, a display, and the like can be exemplified. The hydrophilic member of the present embodiment can be used for a greenhouse sheet, a food package, or the like, which requires antifogging properties, in addition to the above-described members.
The hydrophilic member of the present embodiment is not limited to use for the purpose of antifogging property, and can be preferably used, for example, in a site where it is necessary to impart hydrophilicity such as removal of oil. When the hydrophilic member is used for removing oil, examples of the hydrophilic member include a range hood, a kitchen storage door, a kitchen console, a sink, a kitchen range periphery, a chopping board, a kitchen periphery floor, and a kitchen member such as a refrigerator. Oil stains such as lipid peroxides are likely to adhere to the surfaces of such kitchen members and the like. However, by providing the hydrophilic film of the present embodiment, both of the oil stain at the initial stage of just adhering and the oil that has already been sticky can be easily removed with water. Further, the oil stain is typically edible oil used in kitchens, but is not limited thereto, and oils and fats due to hand stains, fingerprints, sebum, sweat, and the like can also be removed.