JP2013147568A - Uv cationic curing type coating composition, cured coated film formed by using the same and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a UV cationic curing type coating composition capable of forming cured coated film having a high surface hardness.SOLUTION: A UV cationic curing type coating composition includes a bivalent-trivalent metal-based organic-inorganic layered composite expressed by formula (1): [RSiO][(MO)(MO)][HO](1) [wherein, Ris an organic group having at least one functional group of among epoxy, oxetanyl and vinyl ether; Mis a bivalent metal atom; Mis a trivalent metal atom; (n) is a 1-3 integer; (x), (y), and (z) are arbitrary numbers satisfying conditions described by 0.5≤x/(y+2z/3)≤3; and (w) is the number of structural water molecules] and having 1 to 67% of the number of the trivalent metal atoms based on 100 of the total number of the bivalent metal atoms and trivalent metal atoms, a UV cationic curing type monomer, and a photocationic polymerization initiator.

Description

  The present invention relates to a UV cationic curable coating composition, a cured coating film using the same, and a method for producing the same.

  The UV cationic curable coating composition is (i) less susceptible to curing inhibition by oxygen than the UV radical curable coating composition, (ii) the curing reaction proceeds even after light irradiation, (iii) as a monomer Use of the ring-opening polymerization type monomer has advantages that volume shrinkage during curing can be reduced, residual stress of the cured coating film is reduced, and a cured coating film having excellent adhesion can be obtained. However, since the UV cationic curable monomer has a slower polymerization rate than the UV radical curable monomer, it is difficult to form a cured coating film having a sufficiently high surface hardness.

  Therefore, a resin composition containing metal oxide fine particles has been proposed as a UV cation curable resin composition with improved photocurability (for example, JP 2000-26730 A (Patent Document 1), international publication). 2004/033532 (Patent Document 2), JP-A-2005-89697 (Patent Document 3)). In such a resin composition, in order to enhance the dispersibility of the metal oxide fine particles, the metal oxide fine particles are uniformly dispersed using a dispersant such as an organosilane compound. However, in order to obtain a cured film having a high hardness, the dispersion method of metal oxide fine particles using a dispersant is not necessarily a sufficient method, and more highly inorganic fine particles such as metal oxide fine particles are contained in the resin. Needed to be dispersed.

  On the other hand, as a resin composition in which an organic-inorganic composite whose inorganic fine particles are treated with an organic compound is dispersed in a resin, an adhesive containing a magnesium silicon layered polymer having an epoxy group and polymercaptan or an epoxy compound is used. Agents (JP-A-9-71763 (Patent Document 4), JP-A-2008-115299 (Patent Document 5)) have been proposed, and a strong adhesive force can be obtained by thermosetting such an adhesive. It is expressed.

JP 2000-26730 A International Publication No. 2004/033532 JP 2005-89697 A JP-A-9-71763 JP 2008-115299 A

  However, when the organic-inorganic composite described in Patent Documents 4 to 5 is added to the UV cationic curable coating composition, a cured coating film having sufficient hardness can be obtained, but a transparent cured coating film having excellent water resistance can be obtained. It was difficult to get.

  The present invention has been made in view of the above-described problems of the prior art, and forms a transparent cured coating film having sufficient hardness and excellent water resistance without impairing adhesion to a substrate. An object of the present invention is to provide a UV cationic curable coating composition capable of satisfying the requirements.

  As a result of intensive studies to achieve the above object, the inventors of the present invention have at least one functional group of an epoxy group, an oxetanyl group, and a vinyl ether group, and a divalent metal atom such as an Mg atom. The bivalent-trivalent metal-based organic / inorganic layered composite containing a trivalent metal atom such as an Al atom exhibits excellent dispersibility in the UV cation curable coating composition, and as a result, has sufficient hardness. It has been found that a transparent cured coating film having excellent water resistance can be obtained. Furthermore, even in the case of the bivalent-trivalent metal-based organic / inorganic layered composite as described above, if the content of Al atoms, which are trivalent metal atoms, is excessively increased, the water resistance of the cured coating film decreases. As a result, the present invention has been completed.

That is, the UV cation curable coating composition of the present invention has the following formula (1):
[R ¹ _n SiO _{(4-n) / 2} ] _x [(M ¹ _2/2 O) _y (M ² _2/3 O) _z ] [H ₂ O] _w (1)
(In formula (1), R ¹ represents an organic group having at least one functional group of an epoxy group, an oxetanyl group, and a vinyl ether group, M ¹ represents a divalent metal atom, and M ² represents a trivalent group. N is an integer of 1 to 3, x, y, and z are any numbers satisfying the condition represented by 0.5 ≦ x / (y + 2z / 3) ≦ 3, and w Represents the number of molecules of structural water.)
A bivalent-trivalent metal-based organic-inorganic layered composite in which the number of trivalent metal atoms is 1 to 67% with respect to the total number of atoms of divalent metal atoms and trivalent metal atoms of 100 ,
It contains a UV cationic curable monomer and a photocationic polymerization initiator. Moreover, the cured coating film of the present invention is obtained by irradiating the coating film made of the UV cationic curable coating composition of the present invention with ultraviolet rays to photocur the coating film.

  In the UV cationic curable coating composition of the present invention, the trivalent metal atom is preferably at least one metal atom of aluminum (Al) and iron (III) (Fe (III)), Examples of the valent metal atom include magnesium (Mg), nickel (II) (Ni (II)), cobalt (II) (Co (II)), copper (II) (Cu (II)), manganese (Mn), At least one metal atom selected from the group consisting of iron (II) (Fe (II)), lithium (Li), vanadium (II) (V (II)), zirconium (Zr) and zinc (Zn); Preferably, the UV cation curable monomer is preferably at least one compound selected from the group consisting of epoxy compounds, oxetane compounds, vinyl ether compounds, and styrene compounds.

  In the divalent-trivalent metal-based organic-inorganic layered composite having the functional group and containing a divalent metal atom and a trivalent metal atom, the content of Al atoms that are trivalent metal atoms The reason why the water resistance of the cured coating film is lowered when the amount of C is too large is not certain, but the present inventors speculate as follows. That is, the bivalent-trivalent metal-based organic / inorganic layered composite according to the present invention comprises an organoalkoxysilane having a functional group such as an epoxy group, a divalent metal compound containing a divalent metal atom, and a trivalent metal atom. It is formed by hydrolyzing and dehydrating and condensing a trivalent metal compound. In this case, when aluminum hydrate is used as the trivalent metal compound, it is presumed that the aluminum chloride acts as a nucleophile and the epoxy group, oxetanyl group and vinyl group are cleaved by hydrolysis or solvolysis. It is assumed that functional groups such as epoxy groups do not react with the UV cation curable monomer when cleaved, so that the cross-linking reaction between the organic-inorganic layered composite and the UV cation curable monomer does not proceed and the water resistance of the cured coating film decreases. Is done. And since the cleavage of epoxy group, oxetanyl group and vinyl group appears more prominently as the amount of aluminum chloride hydrate increases, the content of Al atom exceeds 67%. In the UV cation curable coating composition containing the composite, it is presumed that the water resistance of the cured coating film is particularly low.

  According to the present invention, a transparent cured coating film containing an organic / inorganic layered composite having excellent dispersibility and having sufficient hardness and excellent water resistance without impairing excellent adhesion to a substrate. Can be obtained.

It is a schematic diagram which shows an example of the layer structure of the bivalent-trivalent metal type organic inorganic layered composite concerning this invention. It is a schematic diagram which shows an example of the layer structure of the conventional bivalent metal type organic inorganic layered composite. It is a graph which shows the ¹³ C-CP / MAS NMR spectrum of each layered composite obtained in Preparation Examples 1-5. (A) alicyclic epoxy-Al-Mg-based layered composite (Al: 50%), (b) 3,4-epoxycyclohexenylmethyl-3 ′, 4′-epoxycyclohexenecarboxylate, (c) alicyclic ring It is a graph which shows the X-ray-diffraction pattern of the mixture of a formula epoxy-Al-Mg type | system | group layered composite (Al: 50%) and 3,4-epoxycyclohexenylmethyl-3 ', 4'-epoxycyclohexene carboxylate. (A) Glycidyl-Mg-based layered composite (Al: 0%), (b) 3,4-epoxycyclohexenylmethyl-3 ′, 4′-epoxycyclohexenecarboxylate, (c) Glycidyl-Mg-based layered composite 2 is a graph showing an X-ray diffraction pattern of a mixture of (Al: 0%) and 3,4-epoxycyclohexenylmethyl-3 ′, 4′-epoxycyclohexenecarboxylate. 2 is a photograph showing the thin film (cured coating film) obtained in Example 1. FIG. 2 is a photograph showing the thin film (cured coating film) obtained in Example 2. FIG. 4 is a photograph showing the thin film (cured coating film) obtained in Example 3.

  Hereinafter, the present invention will be described in detail with reference to preferred embodiments thereof.

  The UV cation curable coating composition of the present invention includes a divalent to trivalent metal-based organic / inorganic layered composite containing a functional group such as an epoxy group, a divalent metal atom, and a trivalent metal atom, UV cation curing Type monomer and a cationic photopolymerization initiator.

(Divalent to trivalent metal-based organic / inorganic layered composite)
The bivalent-trivalent metal-based organic / inorganic layered composite used in the present invention (hereinafter also simply referred to as “organic / inorganic layered composite according to the present invention”) is represented by the following formula (1):
[R ¹ _n SiO _{(4-n) / 2} ] _x [(M ¹ _2/2 O) _y (M ² _2/3 O) _z ] [H ₂ O] _w (1)
(In formula (1), R ¹ represents an organic group having at least one functional group of an epoxy group, an oxetanyl group, and a vinyl ether group, M ¹ represents a divalent metal atom, and M ² represents a trivalent group. N is an integer of 1 to 3, x, y, and z are any numbers satisfying the condition represented by 0.5 ≦ x / (y + 2z / 3) ≦ 3, and w Represents the number of molecules of structural water.)
It is represented by

As shown in FIG. 1, the organic-inorganic layered composite according to the present invention is a layer formed by an octahedral structure containing a divalent metal atom M ¹ and a trivalent metal atom M ² as a central atom (hereinafter referred to as “a”). An inorganic layer 1 composed of a layer (hereinafter referred to as “tetrahedral sheet”) 1b formed of a tetrahedral structure containing Si atoms as a central atom (hereinafter referred to as “octahedral sheet”) and a covalent bond to the Si atoms A layer structure formed by an organic layer 2 composed of an organic group 2a bonded and having at least one functional group X of an epoxy group, an oxetanyl group and a vinyl ether group (FIG. 1 shows a 2: 1 type layered silicate) It is inferred to have a structure.

Such an organic-inorganic layered composite in which a divalent metal atom M ¹ and a trivalent metal atom M ² are mixed as the central atom of the octahedral sheet has 2 as the central atom of the octahedral sheet as shown in FIG. compared to organic-inorganic layered composite containing only the valence of the metal atom M ^1, they tend to excellent dispersibility of the UV cationically curable coating composition. As a result, the organic-inorganic layered composite in which the divalent metal atom M ¹ and the trivalent metal atom M ² are mixed as the central atom of the octahedral sheet is highly dispersed in the obtained cured coating film. Therefore, a cured coating film having sufficient hardness and excellent transparency can be formed.

  In the organic-inorganic layered composite according to the present invention, the number of trivalent metal atoms is 1 to 67% based on the total number of atoms 100 of divalent metal atoms and trivalent metal atoms. When the number of trivalent metal atoms is less than the lower limit, the dispersibility of the organic-inorganic layered composite according to the present invention in the UV cation curable coating composition is lowered. When an Al atom is used as a valent metal atom, a functional group such as an epoxy group is cleaved, so that the crosslinking reaction between the organic-inorganic layered composite according to the present invention and the UV cation curable monomer does not proceed, and the cured coating is not performed. The water resistance of the membrane decreases. Further, from the viewpoint that functional groups such as epoxy groups are difficult to cleave, the content of the trivalent metal atom is preferably 55% or less.

  In the organic-inorganic layered composite according to the present invention, the content of the trivalent metal atom is preferably 45% or less, more preferably 30% or less, and 15% or less. Further preferred. When the content of the trivalent metal atoms is in the above range, the content of siloxane bonds is increased compared to silanol groups, and the mechanical strength (for example, hardness) of the tetrahedral sheet is improved. The mechanical strength (for example, hardness) of the organic / inorganic layered composite is improved, and the surface hardness of the cured coating film of the present invention tends to increase.

  Furthermore, in the organic-inorganic layered composite according to the present invention, the content of the trivalent metal atom is particularly preferably 10% or less. When the content of trivalent metal atoms is 10% or less, the mechanical strength (for example, hardness) of the octahedral sheet is further improved, so that the mechanical strength (for example, hardness) of the organic-inorganic layered composite according to the present invention is improved. ) And the surface hardness of the cured coating film of the present invention tends to increase.

M ¹ in the formula (1) according to the present invention represents a divalent metal atom. Such divalent metal atoms include magnesium (Mg), nickel (II) (Ni (II)), cobalt (II) (Co (II)), copper (II) (Cu (II)), manganese (Mn), iron (II) (Fe (II)), lithium (Li), vanadium (II) (V (II)), zirconium (Zr), zinc (Zn), among others, the UV of the present invention. In the cationic curable coating composition, magnesium (Mg) and nickel (II) (Ni (II)) are preferable, and magnesium (Mg) is preferable from the viewpoint of high dispersibility of the organic-inorganic layered composite according to the present invention. Is particularly preferred. The organic-inorganic layered composite according to the present invention may contain one kind of such divalent metal atoms, or may contain two or more kinds.

Further, M ² in the formula (1) represents a trivalent metal atom. Examples of such trivalent metal atoms include aluminum (Al) and iron (III) (Fe (III)). Among them, the organic material according to the present invention is used in the UV cation curable coating composition of the present invention. Aluminum (Al) is preferable from the viewpoint of increasing dispersibility of the inorganic layered composite. The organic-inorganic layered composite according to the present invention may contain one kind of such trivalent metal atoms alone, or may contain two or more kinds.

R ¹ in the formula (1) according to the present invention represents an organic group having at least one functional group of an epoxy group, an oxetanyl group, and a vinyl ether group, and the organic-inorganic layered composite according to the present invention to be described later It is derived from the organoalkoxysilane having the functional group used in the production method. Since the organic-inorganic layered composite according to the present invention has such an organic group having a functional group, it can form a crosslinked structure with the UV cation curable monomer, and as a result, cured with excellent water resistance. A coating film is obtained. Examples of the epoxy group include a glycidyl group and an alicyclic epoxy group, and among them, an alicyclic epoxy group is preferable from the viewpoint of increasing the reactivity with the UV cation curable monomer. Moreover, there is no restriction | limiting in particular as carbon number of the said organic group, For example, 3-18 are preferable and 3-12 are more preferable.

  Such an organic group is not particularly limited as long as it has the functional group. For example, an alkyl group (for example, a methyl group, an ethyl group, a propyl group, a butyl group, a hexyl group, an octyl group, a decyl group, an undecyl group) , A dodecyl group, a tridecyl group, a hexadecyl group, an octadecyl group), an alkenyl group (for example, a vinyl group), an aryl group (for example, a phenyl group), or the like, and the functional group bonded thereto.

  X, y and z in the formula (1) are the amounts of silicon atom, divalent metal atom and trivalent metal atom contained in the raw material used in producing the organic-inorganic layered composite according to the present invention. Can be determined based on x / (y + 2z / 3) represents a molar ratio between Si atoms and metal atoms (a divalent metal atom and a trivalent metal atom) contained in the organic-inorganic layered composite according to the present invention.

  The structural water is derived from a hydroxyl group constituting a silanol group in the tetrahedral sheet, a hydroxyl group bonded to a divalent or trivalent metal atom in the octahedral sheet, and the presence thereof is a nuclear magnetic field. This can be confirmed by resonance (NMR) measurement. Since the tetrahedral structure may contain a silanol group, the value of w is not limited to an integer, but [(y + z) / (y + 2z / 3)]-1 ≦ w / ( It is preferable that the condition represented by y + 2z / 3) ≦ [(y + z) / (y + 2z / 3)] + (1/2) is satisfied. w / (y + 2z / 3) represents the molar ratio between structural water and metal atoms (a divalent metal atom and a trivalent metal atom).

  The organic-inorganic layered composite according to the present invention can be prepared, for example, through a preparation process, a reaction process, and a removal process described below.

[Preparation process]
First, an organoalkoxysilane having at least one functional group of an epoxy group, an oxetanyl group and a vinyl ether group (hereinafter referred to as “functional group-containing organoalkoxysilane”), a divalent metal compound containing a divalent metal atom, and 3 A trivalent metal compound containing a valent metal atom is dissolved in a first solvent, which is a polar solvent, to prepare a raw material solution containing a silicon atom, a divalent metal atom, and a trivalent metal atom. The “dissolution” in this step includes a state in which one or more of the functional group-containing organoalkoxysilane, divalent metal compound and trivalent metal compound are dispersed as particles in the first solvent.

The functional group-containing organoalkoxysilane used in the present invention is represented by the following formula (2):
R ¹ _n Si (OR ² ) _(4-n) (2)
(In the formula (2), R ¹ is an epoxy group, an organic group having at least one functional group of the oxetanyl group and vinyl ether group, OR ² represents an alkoxy group, n represents an integer from 1 to 3 is there.)
As long as it is represented by The Si atom constituting the functional group-containing organoalkoxysilane is the Si atom constituting the organic / inorganic layered composite according to the present invention (preferably the central atom of the tetrahedral sheet in the organic / inorganic layered composite according to the present invention). The organic group R ¹ in the formula (2) becomes the organic group R ¹ having the functional group constituting the organic layer in the organic-inorganic layered composite according to the present invention.

OR ² in the formula (2) represents an alkoxy group. Although there is no restriction | limiting in particular as such an alkoxy group, C1-C3 alkoxy groups, such as a methoxy group and an ethoxy group, are preferable. The functional group-containing organoalkoxysilane may contain one kind of such alkoxy groups alone, or may contain two or more kinds.

  The functional group-containing organoalkoxysilane has an alicyclic epoxy-based organoalkoxysilane such as an alkoxysilane having an epoxycyclohexyl group represented by the following formula (2a), and a glycidyl group represented by the following formula (2b). Glycidyl organoalkoxysilanes such as alkoxysilanes, oxetane organoalkoxysilanes such as alkoxysilanes having an oxetanyl group represented by the following formula (2c), alkoxysilanes having a vinyloxy group represented by the following formula (2d), etc. A vinyl ether organoalkoxysilane is mentioned. Among these, the fat represented by the following formula (2a) from the viewpoint that the reactivity between the organic-inorganic layered composite according to the present invention and the UV cation curable monomer increases and the water resistance of the cured coating film is improved. Cyclic epoxy organoalkoxysilane is preferred. Such functional group-containing organoalkoxysilanes may be used alone or in combination of two or more.

In the formulas (2a) to (2d), OR ² is synonymous with OR ² in the formula (2), and R ³ is an organic group having 1 to 8 carbon atoms which may have an ether bond. R ⁴ represents an organic group having 1 to 3 carbon atoms, and n has the same meaning as n in formula (2).

  Examples of the epoxycyclohexyl group-containing alkoxysilane represented by the formula (2a) include 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltriethoxysilane, Examples include 2- (3,4-epoxycyclohexyl) ethylmethyldiethoxysilane. Examples of the glycidyl group-containing alkoxysilane represented by the formula (2b) include 3-glycidyloxypropyltrimethoxysilane, 3-glycidyloxypropyltriethoxysilane, and 3-glycidyloxypropylmethyldiethoxysilane. .

  Examples of the oxetanyl group-containing alkoxysilane represented by the formula (2c) include [(3-methyloxetane-3-yl) -methyloxypropyl] -trimethoxysilane and [(3-methyloxetane-3). -Yl) -methyloxypropyl] -triethoxysilane, [(3-methyloxetane-3-yl) -methyloxypropyl] -methyldiethoxysilane, 2-[(3-methyloxetane-3-yl) -methyl Roxypropyl] -ethoxyethyltrimethoxysilane, 2-[(3-methyloxetane-3-yl) -methyloxypropyl] -ethoxyethyltriethoxysilane, 2-[(3-methyloxetane-3-yl) -methyl Roxypropyl] -ethoxyethylmethyldiethoxysilane, etc., paragraph [0 of JP 2000-26730 A 40], and alkoxysilanes according to [0041]. Examples of the vinyl ether group-containing alkoxysilane represented by the formula (2d) include 2- (vinyloxy) ethyltrimethoxysilane, 2- (vinyloxy) ethyltriethoxysilane, 2- (vinyloxy) ethylmethyldiethoxysilane, and the like. Is mentioned.

  Moreover, in order to adjust the amount of the functional group contained in the organic-inorganic layered composite according to the present invention, if necessary, an organoalkoxysilane having no functional group or an alkoxysilane not containing an organic group contains the functional group. It can be used in combination with an organoalkoxysilane. Examples of the organoalkoxysilane having no functional group include alkyl alkoxysilanes and aromatic alkoxysilanes. Examples of alkoxysilanes that do not contain an organic group include tetramethoxysilane (TMOS), tetraethoxysilane (TEOS), tetra-n-propoxysilane, tetraisopropoxysilane, tetra-n-butoxysilane, and tetra-sec-butoxy. Examples thereof include silane and tetra-tert-butoxysilane. Such alkoxysilane may be used individually by 1 type, or may use 2 or more types together. When the proportion of organoalkoxysilane having no functional group or alkoxysilane containing no organic group is large, the number of reaction points with the UV cation curable monomer is reduced in the organic / inorganic layered composite according to the present invention. The water resistance of the cured coating film tends to decrease. Therefore, when an organoalkoxysilane having no functional group or an alkoxysilane not containing an organic group is used in preparing the organic / inorganic layered composite according to the present invention, the amount of these alkoxysilanes used (when used in combination) The total amount thereof) should be 50 mol% or less of the total amount of alkoxysilane used (the total amount of the functional group-containing organoalkoxysilane, the functional group-free organoalkoxysilane and the organic group-free alkoxysilane). Is preferred.

  The divalent metal compound used in the present invention is not particularly limited as long as it is a metal compound containing a divalent metal atom as described above, but from the viewpoint of reactivity with a functional group-containing organoalkoxysilane or a trivalent metal compound. Inorganic salts, organic salts and alkoxides of divalent metal atoms are preferred. As the inorganic salt, chloride, sulfide, sulfate, nitrate and the like are preferable. As the organic salt, acetate and the like are preferable. As the alkoxide, methoxide, ethoxide, propoxide, butoxide and the like are preferable. Such divalent metal compounds may be used alone or in combination of two or more.

  The trivalent metal compound used in the present invention is not particularly limited as long as it is a metal compound containing a trivalent metal atom as described above, but from the viewpoint of reactivity with a functional group-containing organoalkoxysilane or a divalent metal compound. Inorganic salts, organic salts and alkoxides of trivalent metal atoms are preferred. As the inorganic salt, chloride, sulfide, sulfate, nitrate and the like are preferable. As the organic salt, acetate and the like are preferable. As the alkoxide, methoxide, ethoxide, propoxide, butoxide and the like are preferable. Such trivalent metal compounds may be used alone or in combination of two or more.

  In this preparation step, such a functional group-containing organoalkoxysilane, divalent metal compound and trivalent metal compound are dissolved in a first solvent which is a polar solvent to prepare a raw material solution. As a 1st solvent used at this time, if it is a polar solvent, an inorganic type polar solvent (for example, water, an inorganic acid), an organic type polar solvent (for example, alcohol, acetone, organic acid), and these 2 or more types of Any of the mixed solvents can be used. Among them, water, a water-soluble organic solvent (for example, a lower alcohol such as a chain alcohol having 1 to 5 carbon atoms, acetone), and a mixed solvent of two or more of these are used. preferable.

  In such a preparation step, the atomic ratio of silicon atoms to metal atoms (number of silicon atoms / total number of atoms of divalent metal atoms and trivalent metal atoms contained in the obtained raw material solution. The raw material solution is prepared so that “the number of silicon atoms / the number of metal atoms” is 0.5 or more and 3 or less. By adjusting the atomic ratio of silicon atoms and metal atoms in the raw material solution to the above range, a tetrahedral sheet whose central atom is a silicon atom and an octahedral sheet whose central atom is a divalent and trivalent metal atom are formed. An inorganic layer having a 2: 1 type or 1: 1 type phyllosilicate structure can be formed. In particular, an inorganic layer having a 2: 1 type phyllosilicate structure can be formed by adjusting the number of silicon atoms / number of metal atoms to 1 or more and 3 or less, and by adjusting to 0.5 or more and 1 or less. An inorganic layer having a 1: 1 type phyllosilicate structure can be formed.

  Further, in such a preparation step, the number of trivalent metal atoms contained in the obtained raw material solution is 1 to 67% with respect to 100 total atoms of the divalent metal atom and the trivalent metal atom. The raw material solution is prepared so that When the number of trivalent metal atoms exceeds the above upper limit, when an Al atom is used as the trivalent metal atom, a functional group such as an epoxy group is cleaved and a crosslinking reaction with the UV cation curable monomer proceeds. Without, the water resistance of the cured coating film decreases. Moreover, it is preferable to adjust content of the said trivalent metal atom to 55% or less from a viewpoint that functional groups, such as an epoxy group, become difficult to cleave.

  In such a preparation step, the content of the trivalent metal atom is preferably adjusted to 45% or less, more preferably adjusted to 30% or less, and further adjusted to 15% or less. preferable. As a result, the content of the siloxane bond can be increased as compared with the silanol group. As a result, the mechanical strength (for example, hardness) of the tetrahedral sheet is increased, so that the organic-inorganic layered composite according to the present invention Mechanical strength (for example, hardness) also increases, and the surface hardness of the cured coating film of the present invention tends to increase.

  Furthermore, in such a preparation step, it is particularly preferable to adjust the content of the trivalent metal atom to 10% or less. Thereby, since the mechanical strength (for example, hardness) of the octahedral sheet is further improved, the mechanical strength (for example, hardness) of the organic-inorganic layered composite according to the present invention is improved. The surface hardness tends to increase.

[Reaction process]
Next, the functional group-containing organoalkoxysilane, the divalent metal compound, and the trivalent metal compound are hydrolyzed and dehydrated and condensed to contain silicon atoms, divalent metal atoms, and trivalent metal atoms. A bivalent-trivalent metal-based organic / inorganic layered composite is synthesized. When water is present in the raw material solution prepared in the preparation step, the functional group-containing organoalkoxysilane, the divalent metal compound, and the trivalent metal compound are hydrolyzed and dehydrated and condensed. On the other hand, when water does not exist in the raw material solution, the hydrolysis reaction and dehydration condensation reaction proceed by adding water to the raw material solution. The amount of water added is not particularly limited as long as the functional group-containing organoalkoxysilane, the divalent metal compound, and the trivalent metal compound can be sufficiently hydrolyzed.

  Moreover, in such a reaction process, it is preferable to adjust the pH of the raw material solution to be alkaline. Thereby, reaction with the said functional group containing organoalkoxysilane, the said bivalent metal compound, and the said trivalent metal compound can be accelerated | stimulated. Such pH adjustment is particularly effective when inorganic and / or organic salts of divalent and trivalent metal atoms are used as the divalent and trivalent metal compounds. Although there is no restriction | limiting in particular as the alkali added in the said pH adjustment, It is preferable to add sodium hydroxide, potassium hydroxide, ammonia, etc. in the state of aqueous solution. The pH of the raw material solution adjusted in this way is not particularly limited as long as it is a pH at which crystallization occurs at a desired rate or higher and is not strongly alkaline so that the organic group is damaged. Since it depends on the type of the group-containing organoalkoxysilane and the divalent and trivalent metal compounds, it cannot be uniformly defined, but it is preferably adjusted to about pH 8-10.

Thus, when water or water and alkali are present in the raw material solution, among the functional group-containing organoalkoxysilane and the divalent and trivalent metal compounds, first, the divalent and trivalent metal compounds are hydrolyzed. Or a metal hydroxide, and in either case, -M ¹ -OH and -M ² -OH are produced. The crystal structure of the hydrolyzate or metal hydroxide formed at this time is assumed to be an octahedral structure containing a divalent metal atom and a trivalent metal atom as a central atom, and this octahedral structure grows. By doing so, it is presumed that an octahedral sheet is formed. Thereafter, -M ¹ -OH and -M ² -OH promote hydrolysis of the functional group-containing organoalkoxysilane and dehydrate-condense it with a silanol group (Si-OH) generated by hydrolysis. to form a bond represented by ^{1 -Si-O-M 1} and ^{R 1 -Si-O-M 2} . At this time, a tetrahedral structure containing Si atoms as a central atom is formed in a state of being bonded to the octahedral structure, and the tetrahedral structure grows following the growth of the octahedral structure, thereby forming a tetrahedral sheet. Presumed to be formed.

  Such hydrolysis reaction and dehydration condensation reaction proceed sufficiently at a temperature around room temperature, but may be performed at a constant high temperature that does not damage the organic group. In addition, such a reaction may be completed immediately depending on conditions, and may require aging to some extent (for example, about 1 to 2 days).

  Raw material (the functional group-containing organoalkoxysilane, divalent metal compound and trivalent metal compound, and use thereof) of the organic-inorganic layered composite according to the present invention in a raw material solution (including those when water or alkali is added) In this case, the initial content of the organoalkoxysilane having no functional group and the alkoxysilane not containing an organic group) is not particularly limited, and the functional group-containing organoalkoxysilane and the divalent and trivalent metal compounds are not limited. Since it depends on the molecular weight, it cannot be defined uniformly. However, the total amount of the raw materials is preferably 25% by mass or less, more preferably 15% by mass or less, with respect to 100% by mass of the total amount of the raw material solution. More preferably, it is% or less.

[Removal process]
Next, a second solvent that is incompatible with the solution is added to the solution obtained in the reaction step, and the organic-inorganic layered composite according to the present invention is dissolved in the second solvent. Since the solution obtained in the reaction step and the second solvent are separated into two phases, the organic / inorganic layered composite according to the present invention is used as the second solvent by removing the solution incompatible with the second solvent. It can be recovered in a dissolved state.

  The second solvent is not particularly limited as long as it is incompatible with the solution obtained in the reaction step and can dissolve the organic-inorganic layered composite according to the present invention. When water, a water-soluble organic solvent, or a mixed solvent thereof is used as the solvent, since the solution obtained in the reaction step is an aqueous solution or an aqueous solution, the organic solvent used as an extraction solvent from the aqueous solution or the aqueous solution is used. A solvent can be used as the second solvent. Examples of such an organic solvent include n-pentane, 2-methylbutane, 2,2-dimethylpropane, n-hexane, 2-methylpentane, 3-methylpentane, 2,2-dimethylbutane, 2,3- Dimethylbutane, n-heptane, 2-methylhexane, 3-methylhexane, 2,3-dimethylpentane, 2,4-dimethylpentane, n-octane, 2,2,3-trimethylpentane, 2,2,4- Aliphatic hydrocarbons such as trimethylpentane, n-nonane, n-decane; alicyclic hydrocarbons such as cyclopentane, methylcyclopentane, cyclohexane, methylcyclohexane, ethylcyclohexane, cyclooctane; aromatic carbonization such as toluene and xylene Hydrogen, diethyl ether, diisopropyl ether, dibutyl ether, etc. Ester such as triethyl orthoformate, methyl acetate, ethyl acetate, butyl acetate; chloroform, carbon tetrachloride, 1,2-dichloroethane, 1,2-dichloroethylene, 1,1,2,2, -tetrachloroethane, chlorobenzene, Halogenated hydrocarbons such as trichlorethylene and tetrachloroethylene are exemplified. Such an organic solvent may be used individually by 1 type, or may use 2 or more types together.

  Since the organic-inorganic layered composite according to the present invention comprises a hydrophilic inorganic layer and a hydrophobic organic layer, the organic-inorganic layered composite functions in the same manner as a surfactant, and the solution obtained in the reaction step and the second solvent Tend to interfere with phase separation. Since such a tendency is more conspicuous as the second solvent is more hydrophobic, an organic solvent that is slightly compatible with water and an aqueous solvent, such as ethyl acetate, toluene, and chloroform, is preferable as the second solvent.

  In such a removal process, after adding a 2nd solvent to the solution obtained at the said reaction process, it fully mixes and it leaves still so that it may be in an equilibrium state. Thereby, the solution is separated into two layers, an upper layer and a lower layer. For example, when water, a water-soluble organic solvent, or a mixed solvent thereof is used as the first solvent, an aqueous solution or aqueous solution is usually located in the lower layer and a solution containing the second solvent in the upper layer. At this time, the organic-inorganic layered composite according to the present invention is mainly present as a solute in the solution containing the second solvent in the upper layer. On the other hand, impurities (for example, by-products generated during pH adjustment, organic-inorganic composites containing more inorganic components than necessary, unreacted materials, etc.) exist as solutes in the lower layer aqueous solution or aqueous solution. In addition, when the second solvent is a solvent having a specific gravity heavier than water, such as a halogen-based solvent, an aqueous solution or an aqueous solution is located in the upper layer, and a solution containing the second solvent is located in the lower layer.

  In this removal step, the same procedure (extraction operation) may be repeated a plurality of times by changing the type of the second solvent as necessary.

[Recovery process]
Next, the second solvent is removed from the solution containing the organic-inorganic layered composite according to the present invention obtained in the removing step, and the organic-inorganic layered composite according to the present invention is solid (preferably powder, more It is preferably recovered in the form of fine particles. Examples of the method for removing the second solvent include a method of evaporating the second solvent using an evaporator or the like. In particular, when ethyl acetate, toluene, chloroform, and a mixed solvent of two or more of these are used as the second solvent, the second solvent is evaporated without exposing the organic-inorganic layered composite according to the present invention to a high temperature. Can do.

(UV cation curable monomer)
There is no restriction | limiting in particular as UV cation curable monomer used for this invention, The monomer used for the conventional UV cation curable coating composition can be used. Such UV cation curable monomers have the advantage that (i) they are not easily inhibited by oxygen, and (ii) the curing reaction proceeds after light irradiation. Further, when a ring-opening polymerization monomer is used, iii) There is an advantage that the volume shrinkage at the time of curing can be reduced, the residual stress of the cured coating film is reduced, and a cured coating film having excellent adhesion can be obtained. That is, even if the UV cationic curable coating composition of the present invention is photocured in the air, a cured coating film having high adhesion to the substrate and excellent in transparency and surface hardness can be obtained. .

  Examples of such UV cation curable monomers include epoxy compounds, oxetane compounds, vinyl ether compounds, and styrene compounds. These UV cation curable monomers may be used alone or in combination of two or more. Among these UV cation curable monomers, from the viewpoint of obtaining excellent photocurability in the UV cation curable coating composition of the present invention, an alicyclic epoxy compound (more preferably, the following formula (i ) And oxetane compounds (more preferably those represented by the following formulas (ii) to (v)). In addition, n in Formula (v) is an integer of 1-3.

(Photocationic polymerization initiator)
There is no restriction | limiting in particular as a photocationic polymerization initiator used for this invention, The photocationic polymerization initiator used for the conventional UV cation-curable coating composition can be used. As such a cationic photopolymerization initiator, onium salts such as iodonium salts and sulfonium salts are preferable. Examples of onium salt counter anions include PF ₆ ⁻ , SbF ₆ ⁻ , AsF ₆ ⁻ , B (C ₆ F ₅ ) ₄ ^{− and the} like.

  Specific examples of such a cationic photopolymerization initiator include “Syracure UVI-6974”, “Syracure UVI-6990”, “Syracure UVI-6990” manufactured by Dow Chemical Co., Ltd .; “Adekaoptomer SP” manufactured by ADEKA Corporation. -150 "," Adekaoptomer SP-152 "," Adekaoptomer SP-170 "," Adekaoptomer SP-172 ";" CPI-100P "," CPI-101A "manufactured by Sun Apro Co., Ltd. “CPI-110P”, “CPI-110A”, “CPI-200K”, “CPI-210S”; “TS-91” manufactured by Sanwa Chemical Co., Ltd .; “Esacure 1187”, “Esacure 1188” manufactured by Lamberti Arylsulfonium salt), “Irgaccu” manufactured by Ciba Specialty Chemicals 250 "; Rhodia" RP-2074 "(or, allyl iodonium salts) commercially available, such as.

<UV cationic curable coating composition>
The UV cation curable coating composition of the present invention comprises the organic-inorganic layered composite according to the present invention, the UV cation curable monomer, and the photocationic polymerization initiator. Moreover, in the UV cation curable coating composition of the present invention, known additives such as a deterioration inhibitor may be contained within a range not impairing the effects of the present invention.

  In the UV cation curable coating composition of the present invention, the content of the organic-inorganic layered composite according to the present invention is 10 to 80 parts by mass with respect to 100 parts by mass in total with the UV cation curable monomer. Preferably, 10-50 mass parts is more preferable. When the content of the organic-inorganic layered composite according to the present invention is less than the lower limit, the surface hardness of the cured coating film tends not to be sufficiently improved. On the other hand, when the content exceeds the upper limit, the smoothness of the cured coating film is impaired. It tends to be.

  In the UV cation curable coating composition of the present invention, the content of the photo cation polymerization initiator is preferably 1 to 10 parts by weight, and 2 to 5 parts by weight with respect to 100 parts by weight of the UV cation curable monomer. Part is more preferred. When the content of the cationic photopolymerization initiator is less than the lower limit, the curing reaction does not proceed even when irradiated with ultraviolet rays, and it tends to be difficult to obtain a cured film with high hardness. Even if it is added in excess, the effect of proceeding the curing reaction is not improved any more, and conversely the photocurability may be lowered.

<Curing coating>
The cured coating film of the present invention is formed by photocuring such a UV cation curable coating composition of the present invention. For example, the UV cation curable coating composition of the present invention is applied to a substrate, and the resulting coating film is irradiated with ultraviolet rays to initiate and advance a photocuring reaction, thereby curing the coating film. Thereby, the adhesive film with respect to a base material is high, and the cured coating film excellent in transparency and surface hardness can be obtained.

  Although there is no restriction | limiting in particular as said base material, From the viewpoint that the cured coating film of this invention expresses the outstanding adhesiveness, the base material made from a polycarbonate is preferable. The ultraviolet light source used for the photocuring reaction is not particularly limited, and examples thereof include ultraviolet lamps such as a low-pressure mercury lamp, a high-pressure mercury lamp, an ultraviolet laser, a xenon lamp, and an alkali metal lamp. The intensity | strength and irradiation time of the ultraviolet-ray irradiated to a coating film are suitably controlled according to the kind of UV cation hardening type monomer and photocationic polymerization initiator to be used, and there is no restriction | limiting in particular.

  EXAMPLES Hereinafter, although this invention is demonstrated more concretely based on an Example and a comparative example, this invention is not limited to a following example.

(Preparation Example 1)
In 250 ml of methanol, 10.2 g (0.05 mol) of magnesium chloride hexahydrate (manufactured by Wako Pure Chemical Industries, Ltd., special grade) was added and dissolved, and 24.6 g (0.10 mol) of this solution was dissolved. 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane (“Silaace S530” manufactured by Chisso Corporation, hereinafter abbreviated as “ECTS”) was added and stirred for 40 minutes. After adding 1000 ml of ion-exchanged water to the obtained solution, immediately after adding 100 ml of 1 mol / L sodium hydroxide aqueous solution (manufactured by Wako Pure Chemical Industries, Ltd., for volumetric analysis), a precipitate was formed. .

  After removing the transparent supernatant of the aqueous solution containing the precipitate, 300 ml of ethyl acetate (manufactured by Wako Pure Chemical Industries, Ltd., Wako First Grade) was added and stirred well, and the precipitate in the aqueous solution was converted to ethyl acetate. It was dissolved and extracted. This extraction operation was repeated three times, and all the precipitates were dissolved in ethyl acetate and collected.

  The obtained solution was concentrated using a rotary evaporator (bath temperature: 30 ° C.), and ethyl acetate was completely removed to obtain an alicyclic epoxy-Mg layered composite (19.2 g).

(Preparation Example 2)
In 200 ml of methanol, 5.10 g (0.025 mol) of magnesium chloride hexahydrate (manufactured by Wako Pure Chemical Industries, Ltd., special grade) was added and dissolved, and 24.6 g (0.10 mol) of this solution was dissolved. 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane (“Silaace S530” manufactured by Chisso Corporation, hereinafter abbreviated as “ECTS”) was added and stirred for 40 minutes. Immediately after adding 1000 ml of ion-exchange water to the resulting solution, 6.05 g (0.025 mol) of aluminum chloride hexahydrate (manufactured by Wako Pure Chemical Industries, Ltd., special grade) was added to 50 ml of methanol. When the dissolved solution was added and 125 ml of a 1 mol / L aqueous sodium hydroxide solution (manufactured by Wako Pure Chemical Industries, Ltd., for volumetric analysis) was added, a precipitate was formed.

  The obtained precipitate was extracted three times with ethyl acetate in the same manner as in Preparation Example 1, and then ethyl acetate was completely removed to obtain an alicyclic epoxy-Al-Mg layered composite (14.7 g).

(Preparation Examples 3 to 4)
Alicyclic epoxy in the same manner as in Preparation Example 2, except that the amount of magnesium chloride hexahydrate, the amount of aluminum chloride hexahydrate and the amount of 1 mol / L sodium hydroxide aqueous solution were changed to the amounts shown in Table 1. An Al—Mg-based layered composite was obtained.

(Preparation Example 5)
Instead of magnesium chloride hexahydrate, 12.1 g (0.05 mol) of aluminum chloride hexahydrate (manufactured by Wako Pure Chemical Industries, Ltd., special grade) was used, and the amount of 1 mol / L sodium hydroxide aqueous solution was adjusted. Except having changed to 150 ml, it carried out similarly to the preparation example 1, and obtained the alicyclic epoxy-Al-type layered composite (19.0g).

(Preparation Example 6)
In 250 ml of methanol, 10.2 g (0.05 mol) of magnesium chloride hexahydrate (manufactured by Wako Pure Chemical Industries, Ltd., special grade) was added and dissolved, and 23.6 g (0.10 mol) of this solution was dissolved. 3-Glycidyloxypropyltrimethoxysilane (“Silaace S510” manufactured by Chisso Corporation, hereinafter abbreviated as “GPTS”) was added and stirred for 40 minutes. To the resulting solution was added 1000 ml of a 0.1 mol / L aqueous sodium hydroxide solution obtained by diluting 100 ml of a 1 mol / L aqueous sodium hydroxide solution (manufactured by Wako Pure Chemical Industries, Ltd., for volumetric analysis) 10 times with water. As a result, a precipitate was formed.

  The obtained precipitate was extracted with ethyl acetate three times in the same manner as in Preparation Example 1, and then ethyl acetate was completely removed to obtain a glycidyl-Mg layered composite (29.5 g).

< ^13C -NMR measurement>
The alicyclic epoxy-Mg layered composite obtained in Preparation Example 1, the alicyclic epoxy-Al-Mg layered composite obtained in Preparation Examples 2 to 4, and the alicyclic obtained in Preparation Example 5 Each of the epoxy-Al-based layered composites was put into a sample holder (“Rotapacker BL4” manufactured by Bruker BioSpin Co., Ltd., product number: K8111101), and a nuclear magnetic resonance (NMR) apparatus (manufactured by Bruker BioSpin Co., Ltd. ¹³ C-CP / MAS NMR spectrum of each layered composite was measured using AVANCE 400 ") under the condition of cumulative number: 3200 times. In FIG. 3, the ¹³ C-CP / MAS NMR spectrum of each layered composite obtained in Preparation Examples 1 to 5 is shown. FIG. 3 also shows the relationship between the peak position in the NMR spectrum and the carbon atom in the 2- (3,4-epoxycyclohexyl) ethyl group bonded to the Si atom.

  As shown in FIG. 3, the 10 ppm peak is the carbon atom (h) bonded to the Si atom, the 53 ppm peak is the two carbon atoms (a, b) constituting the epoxy group, and the 20 to 40 ppm peak is the remaining Assigned to 5 carbon atoms (c to g). The layered composite having a peak at 53 ppm indicates that the alicyclic epoxy group does not open and retains its structure. Therefore, as is clear from the results shown in FIG. 3, in the layered composite having Al atoms of 67% or less, peaks derived from the two carbon atoms (a, b) constituting the epoxy group are observed, It was confirmed that the cyclic epoxy group was retained. On the other hand, in the layered composite in which Al atoms are 85% and 100%, the peak derived from the two carbon atoms (a, b) constituting the epoxy group is not observed, and the alicyclic epoxy group is cleaved. I understood it.

<X-ray diffraction (XRD) measurement>
25 parts by mass of the alicyclic epoxy-Al—Mg-based layered composite (Al: 50%) obtained in Preparation Example 2 and 3,4-epoxycyclohexenylmethyl-3 ′, 4 ′, which is a UV cation curable monomer -75 parts by mass of epoxycyclohexene carboxylate ("Celoxide 2021P" manufactured by Daicel Cytec Co., Ltd.) was mixed. This mixture, the alicyclic epoxy-Al-Mg-based layered composite (Al: 50%), and 3,4-epoxycyclohexenylmethyl-3 ′, 4′-epoxycyclohexenecarboxylate were respectively added to glass sample holders (( Rigaku Co., Ltd., Cat No. 9200 / 2G, depth 0.2 mm) and using an X-ray diffractometer (Rigaku Co., Ltd. “RINT-TTR”) tube voltage: 50 kV, tube current: 300 mA, radiation The X-ray diffraction pattern was measured under the conditions of source: CuKα, start angle: 2.0 °, end angle: 70 °, scan speed: 2.0 sec. FIG. 4 shows (a) an alicyclic epoxy-Al—Mg-based layered composite (Al: 50%), (b) 3,4-epoxycyclohexenylmethyl-3 ′, 4′-epoxycyclohexene carboxylate, (C) X-ray diffraction pattern of a mixture of an alicyclic epoxy-Al-Mg layered composite (Al: 50%) and 3,4-epoxycyclohexenylmethyl-3 ', 4'-epoxycyclohexenecarboxylate Show.

  As is apparent from the results shown in FIG. 4A, in the alicyclic epoxy-Al-Mg layered composite (Al: 50%), the (001) plane (2θ = around 5 °), (020 ) Diffraction peaks derived from the () plane (near 2θ = 20 °), the (200) plane (near 2θ = 37 °) and the (060) plane (near 2θ = 60 °) were observed. The diffraction peak derived from the (001) plane shows the order in the layer direction, and the diffraction peak derived from the (200) plane and the (060) plane shows the order in the in-plane direction. From these results, the alicyclic epoxy-Al-Mg layered composite (Al: 50%) has a layer structure similar to the 2: 1 type layered silicate structure of smectite layered clay mineral. It was confirmed. Note that the diffraction peak derived from the (020) plane is considered to be a peak due to reflection from an organic substance.

  FIG. 4D shows the difference between the X-ray diffraction pattern (c) of the mixture and the X-ray diffraction pattern (b) of 3,4-epoxycyclohexenylmethyl-3 ′, 4′-epoxycyclohexenecarboxylate. Show. In this result, although diffraction peaks derived from the (200) plane and (060) plane were observed, diffraction peaks derived from the (001) plane were not observed. That is, the alicyclic epoxy-Al-Mg layered composite (Al: 50%) is ordered in the in-plane direction in 3,4-epoxycyclohexenylmethyl-3 ′, 4′-epoxycyclohexenecarboxylate. However, it was confirmed that the layer direction swelled and lost order.

  Similarly, the glycidyl-Mg-based layered composite (Al: 0%) obtained in Preparation Example 6 was mixed with 3,4-epoxycyclohexenylmethyl-3 ′, 4′-epoxycyclohexenecarboxylate ( A layered composite: 25% by mass) was prepared, and an X-ray diffraction pattern was measured. FIG. 5 shows (a) glycidyl-Mg layered composite (Al: 0%), (b) 3,4-epoxycyclohexenylmethyl-3 ′, 4′-epoxycyclohexenecarboxylate, (c) glycidyl- 2 shows an X-ray diffraction pattern of a mixture of an Mg-based layered composite (Al: 0%) and 3,4-epoxycyclohexenylmethyl-3 ′, 4′-epoxycyclohexenecarboxylate.

  As is clear from the results shown in FIG. 5A, even in the glycidyl-Mg layered composite (Al: 0%), the (001) plane (2θ = 6.0 °), the (020) plane (2θ = 21.2 °), diffraction peaks derived from the (200) plane (2θ = 35.2 °) and the (060) plane (2θ = 59.5 °) were observed. From this result, the glycidyl-Mg layered composite (Al: 0%) also has a layer structure (interlayer distance: 1.47 nm) similar to the 2: 1 type layered silicate structure of smectite layered clay mineral. It was confirmed that.

  FIG. 5 (d) shows the difference between the X-ray diffraction pattern (c) of the mixture and the X-ray diffraction pattern (b) of 3,4-epoxycyclohexenylmethyl-3 ′, 4′-epoxycyclohexenecarboxylate. Show. Even in this result, diffraction peaks derived from the (200) plane and (060) plane exhibiting in-plane ordering were observed, but the diffraction peaks derived from the (001) plane exhibiting layered ordering were Not observed. That is, the glycidyl-Mg based layered composite (Al: 0%) also swells in 3,4-epoxycyclohexenylmethyl-3 ′, 4′-epoxycyclohexenecarboxylate and loses the order in the layer direction. It was confirmed that

Example 1
25 parts by mass of the alicyclic epoxy-Al—Mg-based layered composite (Al: 50%) obtained in Preparation Example 2 and 3,4-epoxycyclohexenylmethyl-3 ′, 4 ′, which is a UV cation curable monomer -75 parts by mass of epoxycyclohexene carboxylate ("Celoxide 2021P" manufactured by Daicel Cytec Co., Ltd.) and an iodonium salt-based photopolymerization initiator ((4-methylphenyl) [4- (2-methylpropyl) phenyl] iodonium-hexafluoro A 3: 1 mixture of phosphate and solvent propylene carbonate, “IRGACURE 250” from BASF) 5PHR was mixed to prepare a coating composition.

Bar painter (“Select-Roller A-bar” manufactured by OSG System Products, Bar: OSP-15, wire bar count (corresponding): # 6.6) is applied so that the film thickness after curing is 15 μm, and the irradiation light intensity is 1200 mJ using a UV curing device (1 kW high pressure mercury lamp (“Handy1000” manufactured by Sen Special Light Source Co., Ltd.)). The film was cured by irradiating with ultraviolet rays under the conditions of / cm ² and light irradiation amount: 140 mW.

(Example 2)
A cured coating film was prepared in the same manner as in Example 1 except that 75 parts by mass of 3-ethyl-3-hydroxymethyloxetane (“OXT-101” manufactured by Toagosei Co., Ltd.) was used as the UV cation curable monomer.

(Example 3)
Implemented except that 75 parts by mass of 3-ethyl-3 {[(3-ethyloxetane-3-yl) methoxy] methyl} oxetane (“OXT-221” manufactured by Toagosei Co., Ltd.) was used as the UV cation curable monomer. A cured coating film was prepared in the same manner as in Example 1.

Example 4
25 parts by mass of the alicyclic epoxy-Al-Mg layered composite (Al: 67%) obtained in Preparation Example 3 instead of the alicyclic epoxy-Al-Mg layered composite (Al: 50%) A cured coating film was produced in the same manner as in Example 1 except that it was used.

(Comparative Example 1)
A cured coating film was prepared in the same manner as in Example 1 except that the alicyclic epoxy-Al-Mg-based layered composite (Al: 50%) was not used.

(Comparative Example 2)
The same procedure as in Example 1 was conducted except that the glycidyl-Mg layered composite (Al: 0%) obtained in Preparation Example 6 was used instead of the alicyclic epoxy-Al-Mg layered composite (Al: 50%). A cured coating film was prepared.

(Comparative Example 3)
Example 1 except for the alicyclic epoxy-Mg layer composite (Al: 0%) obtained in Preparation Example 1 instead of the alicyclic epoxy-Al-Mg layer composite (Al: 50%) A cured coating film was prepared in the same manner.

(Comparative Example 4)
Example 1 except for the alicyclic epoxy-Al-based layered composite (Al: 50%) obtained in Preparation Example 5 instead of the alicyclic epoxy-Al-Mg-based layered composite (Al: 50%) A cured coating film was prepared in the same manner.

(Comparative Example 5)
25 parts by mass of the alicyclic epoxy-Al-Mg layered composite (Al: 85%) obtained in Preparation Example 4 instead of the alicyclic epoxy-Al-Mg layered composite (Al: 50%) A cured coating film was produced in the same manner as in Example 1 except that it was used.

<Adhesion>
The adhesiveness of the cured coating films obtained in the examples and comparative examples was measured according to the method described in the cross-cut adhesion test (JIS K5400.88.5). That is, cuts were made in the cured coating film at intervals of 1 mm in length and width to produce a grid of 100 squares. A cellophane adhesive tape (made by Nichiban Co., Ltd., trade name “Cellotape (registered trademark) CT-24”) is strongly pressure-bonded to the surface of the grid, and the tape is abruptly peeled to leave a cured coating film. The number of was measured. The results are shown in Table 2.

<Storage elastic modulus, surface hardness, maximum indentation depth>
The storage elastic modulus, surface hardness and maximum indentation depth of the cured coating films obtained in Examples and Comparative Examples were measured by a nanoindentation method. That is, using a nanoindenter ("TriboScope" manufactured by Heiditron Co., Ltd.), the relationship between the load and indentation depth when the indenter was indented was obtained under the condition of maximum load: 180 μm, and the storage elastic modulus of the cured coating film was obtained from the obtained results. The surface hardness and the maximum indentation depth were determined. The results are shown in Table 2.

<Transparency>
The cured coating films obtained in the examples and comparative examples were observed visually. FIGS. 6-8 is a photograph of the thin film (cured coating film) obtained in Examples 1-3. Moreover, the external appearance of the thin film (cured coating film) obtained in Examples 1 and 4 and Comparative Examples 1 to 5 was determined according to the following criteria. The results are shown in Table 2.
A: Colorless and transparent.
B: Whitening occurs throughout the cured coating film.

<Water resistance>
Laminated plates made of the cured coating film and transparent polycarbonate substrate obtained in Examples and Comparative Examples were immersed in warm water at 40 ° C. for 10 days, then pulled up and dried, and the cured coating film was visually observed and judged according to the following criteria. did. The results are shown in Table 2.
A: Colorless and transparent.
B: Whitening only at the edge of the cured coating film.
C: Slightly whitened at a portion other than the edge of the cured coating film.
D: Whitening occurs throughout the cured coating film.

  As is clear from the results shown in Table 2, the cured coating films obtained in Examples 1 and 4 and Comparative Examples 1 to 5 are all free from peeling of the coating film and have excellent adhesion to the polycarbonate substrate. It was.

  Further, as is clear from the results shown in Table 2, the cured coating film of the present invention containing a divalent-trivalent metal-based organic-inorganic layered composite having an alicyclic epoxy group and Al atoms and Mg atoms ( Examples 1 and 4) have a storage elastic modulus and a surface hardness 2 to 3 times higher than those in the case of not containing an organic-inorganic layered composite (Comparative Example 1), and have a shallow maximum indentation depth (high hardness) It was confirmed that

  Further, as apparent from the results shown in Table 2, a cured coating film containing a bivalent-trivalent metal-based organic-inorganic layered composite having an alicyclic epoxy group and Al atoms and Mg atoms (Example 1) And 4, Comparative Example 5), a cured coating film not containing an organic-inorganic layered composite (Comparative Example 1), and a trivalent metal-based organic-inorganic layered composite having an alicyclic epoxy group and an Al atom. The cured coating film (Comparative Example 4) was excellent in transparency. On the other hand, when a bivalent metal-based organic / inorganic layered composite having an alicyclic epoxy group or glycidyl group and Mg atom is used (Comparative Examples 2 to 3), 2 in the coating composition and in the cured coating film. The valent metal organic-inorganic layered composite was not uniformly dispersed, and the cured coating film was whitened.

  Further, as is clear from the results shown in FIGS. 6 to 8, the characters can be sufficiently read through the laminate comprising the cured coating film obtained in Examples 1 to 3 and a transparent polycarbonate substrate, and UV cation curing is performed. It was confirmed that a cured coating film having excellent transparency was formed regardless of the type of type monomer.

Further, as is clear from the results shown in Table 2, when a bivalent-trivalent metal-based organic / inorganic layered composite containing Al atoms and Mg atoms in a predetermined ratio was used (Examples 1 and 4). Is
A cured coating film excellent in water resistance was formed. On the other hand, when the organic / inorganic layered composite having a high Al atom content was used (Comparative Examples 4 and 5), it was found that the cured coating film was whitened and inferior in water resistance. In Comparative Examples 4 and 5, it is inferred that a part of the alicyclic epoxy group in the organic-inorganic layered composite was cleaved to generate a hydroxyl group, and the crosslinking reaction with the UV cation curable monomer did not proceed. .

  As described above, according to the present invention, it is possible to obtain a UV cation curable coating composition containing an organic / inorganic layered composite having excellent dispersibility and having excellent photocurability. And in the cured coating film of this invention formed by photocuring the coating film which consists of such UV cation curable coating composition of this invention, since an organic inorganic layered composite is disperse | distributed uniformly. Excellent transparency is obtained, and the cured coating film is uniformly strengthened, so that the surface hardness is excellent.

  Therefore, the UV cation curable coating composition of the present invention is capable of forming a cured coating film having excellent transparency and surface hardness without impairing excellent adhesion to the substrate, and therefore requires high wear resistance. It is useful as an exterior paint for automobiles.

  1: Inorganic layer, 1a: octahedral sheet containing divalent and trivalent metal atoms as central atoms, 1b: tetrahedral sheet containing Si atoms as central atoms, 1c: only divalent metal atoms as central atoms Containing octahedral sheet, 2: organic layer, 2a: organic group.

Claims (6)

Following formula (1):
[R ¹ _n SiO _{(4-n) / 2} ] _x [(M ¹ _2/2 O) _y (M ² _2/3 O) _z ] [H ₂ O] _w (1)
(In formula (1), R ¹ represents an organic group having at least one functional group of an epoxy group, an oxetanyl group, and a vinyl ether group, M ¹ represents a divalent metal atom, and M ² represents a trivalent group. N is an integer of 1 to 3, x, y, and z are any numbers satisfying the condition represented by 0.5 ≦ x / (y + 2z / 3) ≦ 3, and w Represents the number of molecules of structural water.)
A bivalent-trivalent metal-based organic-inorganic layered composite in which the number of trivalent metal atoms is 1 to 67% with respect to the total number of atoms of divalent metal atoms and trivalent metal atoms of 100 ,
A UV cation curable coating composition comprising a UV cation curable monomer and a photo cation polymerization initiator.   2. The UV cation curable paint according to claim 1, wherein the trivalent metal atom is at least one metal atom of aluminum (Al) and iron (III) (Fe (III)). Composition.   The divalent metal atom is magnesium (Mg), nickel (II) (Ni (II)), cobalt (II) (Co (II)), copper (II) (Cu (II)), manganese (Mn) At least one metal atom selected from the group consisting of iron (II) (Fe (II)), lithium (Li), vanadium (II) (V (II)), zirconium (Zr) and zinc (Zn) The UV cation curable coating composition according to claim 1 or 2, wherein   The UV cation curable monomer is at least one compound selected from the group consisting of an epoxy compound, an oxetane compound, a vinyl ether compound, and a styrene compound. The UV cation curable coating composition according to any one of the above.   A cured coating film obtained by photocuring the UV cationic curable coating composition according to any one of claims 1 to 4.   A step of coating the UV cation curable coating composition according to any one of claims 1 to 4 on a substrate, and a step of irradiating the obtained coating film with ultraviolet rays to cure the coating film. A method for producing a cured coating film, comprising: