JP2015203114A - Organic-inorganic hybrid particle and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an organic-inorganic hybrid particle capable of two-step curing by energy ray irradiation and heating, allowing a protective film having a high hardness with high abrasion resistance and flexibility with excellent adhesion to a substrate to be formed; and a coating composition which contains the same.SOLUTION: The organic-inorganic hybrid particle has a structure including silicic acid structural units and polymerizable silicon compound residues which are bonded to each other in a complicated form.

Description

  The present invention relates to organic-inorganic hybrid particles, a coating composition containing the same, and a method for producing the same, and more specifically, hybrid particles having a structure in which an organic component and an inorganic component are mixed and a coating composition including the same , As well as their manufacturing methods.

  In recent years, films and moldings of polyethylene terephthalate (PET) resin, polycarbonate (PC) resin, and polymethyl methacrylate (PMMA) resin are used for many devices and parts such as liquid crystal televisions, mobile phones, communication devices, office equipment, and household equipment. The product is widely used instead of glass. These resins are lighter and easier to process than glass, but they are generally inferior in weather resistance and the surface is easily damaged, so that a protective layer is generally provided (Patent Documents 1 to 25).

  As a method for providing a protective layer, a thermosetting method by a condensation reaction of a silanol group or the like and a photocuring method by a polymerization reaction of a radical functional group are known. As the thermosetting method, for example, a silicon-based resin composition is used. A method (Patent Document 1 or the like) is known in which a film is formed by applying to a synthetic resin molded article and curing by heating.

  A silicon-based protective film formed by this thermosetting method has high scratch resistance, but has insufficient adhesion to the substrate. Moreover, since heat processing is required, the energy for it is requested | required and the material of a base material is restrict | limited. Further, the curing is slow and the productivity is not sufficient.

  In order to solve the problems of the conventional thermosetting method, the present inventors have proposed an aqueous coating composition containing organic-inorganic hybrid particles in which active silicic acid is attached or bonded to the surface of organic polymer particles. (Patent Document 14). With this coating composition, it is possible to form a protective film having high adhesion to the substrate and having high scratch resistance. Moreover, it can be cured without heating. However, due to the characteristics due to the condensation reaction of silanol groups and the like, curing takes a certain time, and improvement in terms of production efficiency has been demanded.

On the other hand, the photo-curing method is a method (Patent Documents 2 to 13) in which a composition containing a radical polymerizable monomer as a main component is applied to a substrate and then cured by irradiation with energy rays such as ultraviolet rays (Patent Documents 2 to 13). Since it can be cured quickly, it is more productive than the thermosetting method.
However, since a protective film obtained by polymerizing a radical polymerizable monomer such as a (meth) acrylic monomer lacks weather resistance and scratch resistance, it usually contains an ultraviolet absorber, a silica-based inorganic component, and the like ( Patent Documents 2 to 13).

  For example, a coating composition containing colloidal silica for the purpose of improving scratch resistance is generally known (Patent Documents 2, 6, 15, and 17). However, if only colloidal silica is contained, the scratch resistance and hardness of the protective film to be obtained cannot be improved so much, and there is a problem that the adhesion to the substrate is lowered. On the other hand, a composition containing a component obtained by modifying colloidal silica with a silane coupling agent having a radical polymerizable functional group has been proposed (4, 5, 8, 9). The protective film obtained with this composition has improved scratch resistance and hardness. However, these characteristics are still insufficient, and almost no improvement is observed in terms of adhesion to the substrate.

  Further, a curable resin composition having two or more aliphatic unsaturated bonds and including an organic-inorganic composite composed of cage-type siloxane and an organic component has been proposed (Patent Document 3). This organic-inorganic composite is obtained by condensation reaction of an alkoxysilane having an aliphatic unsaturated bond and an alkoxysilane, and has a structure in which an organic group having an aliphatic unsaturated bond is added to a cage siloxane. The resulting protective film is obtained by polymerization by radical reaction, and the silanol groups that are present a little contribute little to the curing reaction. Moreover, since the cocoon-type siloxane occupies most of the composite and the inorganic component and the organic component are localized, the resulting protective film provides sufficient scratch resistance. There is almost no improvement.

  Also, for the purpose of improving the scratch resistance of the protective film, a coating composition containing poly (meth) acrylate of mono- or polypentaerythritol has also been proposed (Patent Documents 11 to 13). However, the present situation is that such a polyfunctional monomer increases the shrinkage of the coating during curing, causes distortion, and does not provide sufficient scratch resistance and hardness.

US Pat. No. 4,006,271 JP-A-10-279832 JP 2010-195986 A Japanese Patent No. 3747065 JP 7-109355 A JP-A-6-41467 JP2013-249455A JP2010-254840 JP2013-136706 JP 2001-214122 A JP 2000-63701 A JP 05-230397 A JP-A-06-128502 JP2013-72023A JP-A-9-157315 JP 2010-195986 A JP-A-7-247383 JP 5-97422 WO 97/111 Japanese Patent Application No. 9-511845 JP2009-24168 JP2012-188667 JP2013-1000041 JP2013-55973A JP2013-119553A JP-A-6-136335 JP 10-158008 A JP 2000-86934 A JP2009-46323A JP 2000-24588 JP2000-248019 JP 2000-119618 A JP 7-316242 A JP2007-126530

Polymer Digest 1988.9 Naruto Sugawara, published by Rubber Digest Co., Ltd. Introduction to Emulsion Sadao Hayashi Polymer Publishing Co., Ltd. 2nd edition June 5, 1972

In the background art as described above, the present invention is capable of two-stage curing of energy beam irradiation and heating, and forms a protective film having high hardness and excellent scratch resistance and flexibility and excellent substrate adhesion. An object of the present invention is to provide organic-inorganic hybrid particles that can be produced and a coating composition containing the same.
Another object of the present invention is to provide a method for producing organic-inorganic hybrid particles having such excellent properties and a coating composition containing the same.
Furthermore, the present invention can rapidly form a film having flexibility and excellent substrate adhesion by irradiation with energy rays such as ultraviolet rays, and is formed into a film having higher hardness and excellent scratch resistance by heat treatment. It is an object of the present invention to provide a method of forming a protective film that can be used.

  In various stages of studying materials for forming a protective film on a synthetic resin molded product, the present inventors reacted with an alkoxylane compound having a radical polymerizable functional group at the stage of preparing active silicic acid from water glass. As a result, it has been found that conventionally used colloidal silica particles have different physical properties from particles modified with similar alkoxylane compounds. Specifically, the present inventors have found that when a film is formed by irradiation with energy rays such as ultraviolet rays and then further heat-treated, the hardness of the film increases and the film has higher scratch resistance. The present inventors also found that a film formed by polymerizing the particles obtained this time in the absence of other polymerizable components has a relatively high substrate adhesion. Such characteristic properties are the result of the reaction of a low-molecular active silicic acid with a radically polymerizable alkoxylane compound, resulting in a complex mixture of inorganic and organic components (the molecular weight of each structural unit is small) It is understood that a large amount of reactive functional groups such as silanol groups derived from activated silicic acid remain. The present invention has been completed based on such findings.

［式（１）中、aは、１〜５の整数であり、Ｒ¹、Ｒ²、Ｒ³及びＲ⁴は、それぞれ独立して、Ｏ−、Ｏ⁻、ＯＨ、又はＯ⁻Ｎａ^＋であるか、或いはＲ¹及びＲ²、又はＲ³及びＲ⁴は、１つのＯである］
のケイ酸構造単位と、
下記式（２）

［式（２）中、Ｒ^５乃至Ｒ^７の１つ又は２つは、それぞれ独立に、ビニル基、ビニル基含有アルキル基、アクリロイルアルキル基、メタアクリロイルアルキル基、アクリロイルオキシアルキル基、メタアクリロイルオキシアルキル基、又はメルカプトアルキル基（ＳＨ）であり、これらの基中のアルキル基は炭素数２〜１０であり、
Ｒ^５乃至Ｒ^７のその他の部分は、単結合、Ｈ、ＯＨ、Ｏ−、アルキル基（典型的には炭素数５以下のアルキル基）、又はアルコキシル基（典型的には炭素数５以下のアルコキシル基）である］の重合性ケイ素化合物残基とを有し、
式（１）中、Ｒ^１、Ｒ^２、Ｒ^３及びＲ^４の少なくとも１つは、Ｏ−であり、式（２）のＳｉと結合し、Ｒ^１、Ｒ^２、Ｒ^３及びＲ^４のその他の部分の少なくとも１つは、Ｏ⁻、又はＯＨであり、Ｒ^１、Ｒ^２、Ｒ^３及びＲ^４のその他の部分の少なくとも１つは、場合によってはＯ−であり、他のケイ酸構造単位のＳｉに結合してもよく、
式（２）の重合性ケイ素化合物残基のＲ^５乃至Ｒ^７の１つ又は２つは、場合によってはＯ−であり、ケイ酸構造単位又は他の重合性ケイ素化合物残基のＳｉに結合することがあり、
式（１）に示すケイ酸構造単位は１〜２０であり、式（２）に示す重合性ケイ素化合物残基は１〜２００である、有機無機ハイブリッド粒子及びこれを含むコーティング用組成物を提供する。 The present invention, in one embodiment thereof,
Following formula (1)

In Expression (1), a is an integer from 1 to ^{5, R 1, R 2, R} 3 and R ⁴ are each independently, ^O-, O -, OH, or ^O - in Na ⁺ Or R ¹ and R ² , or R ³ and R ⁴ are one O]
Silicate structural units of
Following formula (2)

[In the formula (2), one or two of R ^{5 to} R ⁷ are each independently a vinyl group, a vinyl group-containing alkyl group, an acryloylalkyl group, a methacryloylalkyl group, an acryloyloxyalkyl group, or a methacryloyloxy group. An alkyl group or a mercaptoalkyl group (SH), and the alkyl group in these groups has 2 to 10 carbon atoms,
The other part of R ^{5 to} R ⁷ is a single bond, H, OH, O—, an alkyl group (typically an alkyl group having 5 or less carbon atoms), or an alkoxyl group (typically having 5 or less carbon atoms). A polymerizable silicon compound residue which is an alkoxyl group)
In Formula (1), at least one of R ¹ , R ² , R ^3, and R ⁴ is O—, and is bonded to Si of Formula (2), and R ¹ , R ² , R ^3, and R ⁴ At least one of the other moieties is O ⁻ , or OH, and at least one of the other moieties of R ¹ , R ² , R ^3, and R ⁴ is optionally O— and other silicic acid It may be bonded to the structural unit Si,
One or two of R ^{5 to} R ⁷ of the polymerizable silicon compound residue of the formula (2) is optionally O-, and is bonded to Si of the silicate structural unit or other polymerizable silicon compound residue. There is
Provided are organic-inorganic hybrid particles having a silicic acid structural unit represented by formula (1) of 1 to 20 and a polymerizable silicon compound residue represented by formula (2) of 1 to 200, and a coating composition comprising the same. To do.

  In another embodiment, the present invention provides a radical solution such as a vinyl group, an acryloylalkyl group, a methacryloylalkyl group, an acryloyloxyalkyl group, a methacryloyloxyalkyl group, and a mercaptoalkyl group (SH) in an aqueous solution of activated silicic acid. Provided is a method for producing organic-inorganic hybrid particles, comprising a step of adding a polymerizable alkoxysilane compound having a polymerizable group.

  In still another embodiment, the present invention provides a method for forming a film, in which a coating composition containing the above-described organic-inorganic hybrid particles is applied to a substrate and cured by irradiation with energy rays, and further the film is heated. Provided is a method for forming a protective film including a processing step.

  In still another embodiment, the present invention provides a member or device having a protective film obtained by such a method.

The organic-inorganic hybrid particle of the present invention is obtained by reacting a polymerizable alkoxysilane compound with active silicic acid, and has a structure in which the structural unit of the inorganic component is small and the organic component and the inorganic component are mixed. Yes. Thereby, it is understood that a film having high flexibility and high substrate adhesion is formed. In the organic-inorganic hybrid particles of the present invention, many functional groups such as silanol groups remain in the silicic acid structural unit even after photocuring. It is considered that these functional groups undergo a condensation reaction with each other during the heat treatment to increase the cross-linked structure in the particles and contribute to aggregation between the particles, which leads to higher scratch resistance and hardness. It is understood.
Since the organic-inorganic hybrid particles of the present invention are cured by either heat or light, there is also an advantage that a protective film can be surely formed by two-stage curing even in a molded product including a place where it is difficult to irradiate energy rays due to the structure. is there.

Here, definitions are given for some terms used in this specification.
In the present specification, “silicic acid” means a compound represented by elements of Si and O, or Si, O and H, and has a functional group of Si═O or Si—OH. In the present specification, “active silicic acid” means a compound in which at least part of O and / or OH of silicic acid is O ⁻ . Further, in the present specification, “silicate” means a compound in which at least a part of O and / or OH of silicic acid or active silicic acid is O ⁻ R ⁺ (R ⁺ represents a cation). To do.

In the present specification, the “silicic acid structural unit” means a group of one linear and cyclic structure formed by a repeating structure of Si—O. However, this structural unit, O- bound to ^Si, O -, OH, or ^O - ^M + ^(M represents an alkali metal) are included therein.

  In the present specification, the “polymerizable silicon compound residue” means a group having no Si—O repeating structure but having Si bonded to a silicate structural unit and a radical polymerizable structure.

Hereinafter, embodiments of the present invention will be described in detail.
1. Organic-inorganic hybrid particle The organic-inorganic hybrid particle of the present invention has a structure in which a silicic acid structural unit and a polymerizable silicon compound residue are combined in a complex manner. Specifically, the silicic acid structural unit is much smaller than a generally known silica compound such as colloidal silica, and many polymerizable silicon compound residues are bonded to the silicic acid structural unit. One or more average units per silicic acid structural unit, and in some cases, one or more structural units of polymerizable silicon compounds are bonded per average silicon atom of the silicic acid structural unit. In addition, at least a part of the silicate structural unit may be linked to other active silicate structural units directly or via a polymerizable silicon compound residue. Some polymerizable silicon compound residues may also be bonded to each other. As described above, the organic-inorganic hybrid particle of the present invention has a structure in which the silicic acid structural unit and the structural unit of the polymerizable silicon compound are combined in a complex manner and the inorganic component and the organic component are mixed, and the particle itself Contains relatively many organic components.

  The silicic acid structural unit can take various structures, but usually has a molecular weight (Mn) of 1000 or less, preferably a molecular weight (Mn) of 100 to 400. Moreover, the Si number of a silicic acid structural unit is 1-25 normally, Preferably it is 2-10, More preferably, it is 2-6, Most preferably, it is 3-5. The number of silicic acid structural units in the particles is usually from 1 to 20, and in many particles from 1 to 10, preferably from 1 to 5.

Examples of the silicic acid structural unit include a chain structure including two or more silicons in which two or more SiO ₄ tetrahedra are connected directly or via oxygen, a cyclic structure, and a condensed ring structure.

  In the organic-inorganic hybrid particles of the present invention, the silicic acid structural unit is preferably one having a cyclic structure in terms of easy control of the reaction between the active silicic acid and the polymerizable alkoxysilane compound when preparing the organic-inorganic hybrid particles. A cyclic structure having 2 to 8 silicon atoms is preferable, a cyclic structure having 2 to 6 silicon atoms is more preferable, and a cyclic structure having 3 to 5 silicon atoms is particularly preferable. The silanol group of active silicic acid having a cyclic structure is less reactive than the chain structure, so the reaction pH, the timing of administration of the polymerizable alkoxysilane compound after preparation of the active silicic acid, the active silicic acid and the polymerizability The reaction between the activated silicic acid and the hydrolysis of the polymerizable alkoxysilane compound can be easily controlled by the molar ratio of the alkoxysilane compound, and it becomes easy to obtain organic-inorganic hybrid particles having a desired particle size.

The organic-inorganic hybrid particles of the present invention also have many reactive functional groups such as silanol groups remaining in the silicic acid structural unit. Usually, each silicic acid structural unit has at least one free OH, O or O ⁻ , and these functional groups remain after the polymerization reaction by energy rays such as ultraviolet rays and contribute to the condensation reaction by heat treatment. Can do.
Active silicic acid structural units is usually per one Si atom, the average 0.5 to 1.5 of OH, O or O ^- have, OH most cases the average 0.7 to 1.2, O or O ^- .

［式中、aは、１〜１０の整数であり、Ｒ¹、Ｒ²、Ｒ³及びＲ⁴は、それぞれ独立して、Ｏ−、Ｏ⁻、ＯＨ、又はＯ⁻Ｎａ^＋であるか、或いはＲ¹及びＲ²、又はＲ³及びＲ⁴は、１つのＯである］で表すことができる。 In a preferred embodiment of the present invention, the silicic acid structural unit is represented by the following formula (1):

[Wherein, a is an integer of 1 to 10, and R ¹ , R ² , R ³ and R ⁴ are each independently O−, O ⁻ , OH, or O ⁻ Na ⁺ , Or R ¹ and R ² , or R ³ and R ⁴ are one O].

  In formula (1), a is preferably an integer of 1 to 5, more preferably an integer of 2 to 4.

In formula (1), at least one of R ¹ , R ² , R ³ and R ⁴ is O— and is bonded to Si of the polymerizable silicon compound residue, and in some cases at least R ³ and R ⁴ and any of R ⁵ and R ⁶ are O-, and are bonded to Si of the polymerizable silicon compound residue.
At least one of R ¹ , R ² , R ³ and R ⁴ which is not bonded to Si of the polymerizable silicon compound residue is O ⁻ or OH, preferably bonded to Si of the polymerizable alkoxysilane residue. Among R ¹ , R ² , R ³ and R ⁴ which are not used, at least ^one of R ¹ and R ² and any of R ³ and R ⁴ are O ⁻ or OH.
At least one of R ¹ , R ² , R ³ and R ⁴ is optionally O— and is bonded to Si of another active silicate structural unit.

  In the organic-inorganic hybrid particles of the present invention, the number of silicic acid structural units represented by the formula (1) per particle is preferably 1-20, more preferably 1-10, and particularly preferably 1-5. is there.

［式中、Ｒ^８からＲ^１５は、上述のＲ^１、Ｒ^２、Ｒ^３及びＲ^４と同様である］で表すことができる。
なお、本発明の有機無機ハイブリッド粒子は、複数の異なるケイ酸構造単位で構成されてもよい。 In one aspect of a preferred embodiment, the active silicate structure has, for example, the following formula:

[Wherein R ⁸ to R ¹⁵ are the same as R ¹ , R ² , R ³ and R ⁴ described above].
The organic-inorganic hybrid particles of the present invention may be composed of a plurality of different silicic acid structural units.

In the organic-inorganic hybrid particle of the present invention, the polymerizable silicon compound residue has a structure in which a carbon chain containing an unsaturated bond that can be cleaved by energy rays such as ultraviolet rays and contribute to the polymerization reaction is bonded to silicon. There is no particular limitation other than the above, and various structures can be adopted.
For example, as a structure for introducing an unsaturated bond, it can have a vinyl group, an acryloyl group, a methacryloyl group, an acryloyloxy group, a methacryloyloxy group or a mercapto group (SH), and the transparency of the protective film to be formed, etc. In this respect, an acryloyl group, a methacryloyl group, an acryloyloxy group, a methacryloyloxy group or a mercapto group (SH) is preferable. Examples of the carbon chain (excluding the structure for introducing an unsaturated bond) include, for example, a branched or straight chain alkyl group having 2 to 10 carbon atoms, and includes flexibility, substrate adhesion, hardness, and resistance. An alkyl group having 2 to 5 carbon atoms is preferable, and an alkyl group having 2 to 3 carbon atoms is more preferable from the viewpoint of balance with scratch resistance. The structure for introducing the unsaturated bond may be introduced at any site of the carbon chain, but is usually introduced at the terminal. Further, other substituents may or may not be bonded to silicon. For example, H may be bonded to silicon, OH, an alkyl group having 5 or less carbon atoms (for example, methyl group, ethyl group, butyl group, n-propyl, i-propyl), or a hydroxyalkyl group having 5 or less carbon atoms (for example, A hydroxymethyl group, a hydroxyethyl group, a hydroxybutyl group, a hydroxy n-propyl group, a hydroxy i-propyl group) or an alkoxy group having 5 or less carbon atoms (for example, a methoxy group, an ethoxy group, a butoxy group, an n-propoxy group, i -Propoxy group) may be bonded.
Moreover, when it has OH group, a polymerizable silicon compound residue can also contribute to thermosetting, and a protective group having higher hardness and scratch resistance can be formed.

で表される基である。 In a preferred embodiment, the polymerizable silicon compound residue has the following formula (2):

It is group represented by these.

In formula (2), at least one of R ^{5 to} R ⁷ , typically one or two, is each independently a vinyl group, a vinyl group-containing alkyl group, an acryloylalkyl group, a methacryloylalkyl group, or acryloyl. An oxyalkyl group, a methacryloyloxyalkyl group, or a mercaptoalkyl group, and an acryloylalkyl group, a methacryloylalkyl group, an acryloyloxyalkyl group, a methacryloyloxyalkyl group, or in terms of the transparency of the protective film to be formed, or Mercaptoalkyl groups are preferred. The alkyl group in these groups is 2-10, Preferably it is 2-5, More preferably, it is 2-3.

The other part of R ^{5 to} R ⁷ may be a single bond, H, OH, O—, an alkyl group, or an alkoxyl group, and preferably at least one of R ^{5 to} R ⁷ is OH. The alkyl group is typically an alkyl group having 5 or less carbon atoms, and examples thereof include a methyl group, an ethyl group, a butyl group, n-propyl, and i-propyl. The alkoxy group is typically an alkoxy group having 5 or less carbon atoms, and examples thereof include a methoxy group, an ethoxy group, a butoxy group, an n-propoxy group, and an i-propoxy group. In one embodiment of the invention, R ⁵ is preferably O—, H, CH ₃ , OH, OCH ₃ or OC ₂ H ₅ , more preferably O—, OH. R ⁶ is preferably O—, OH, OCH ₃ or OC ₂ H ₅ , and more preferably O—, OH.

One or two of R ^{5 to} R ⁷ is optionally O— and may be bonded to Si of the silicate structural unit or other polymerizable silicon compound residue.

Si of the polymerizable silicon compound residue represented by the formula (2) is bonded to any one of R ¹ , R ² , R ³ and R ⁴ of the formula (1).

Specific examples of the polymerizable silicon compound residue include a methacryloxymethyltrimethoxysilane residue, a methacryloxymethyltriethoxysilane residue, a methacryloxypropyltrimethoxysilane residue, and a 3-acryloxypropylmethyldimethoxysilane residue. Groups such as 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane residue, 3-acryloxypropyltriethoxysilane residue, vinyltrimethoxysilane residue, vinyltriethoxysilane residue, etc. ) An alkoxysilane residue containing an acrylic group; or 3-mercaptopropyltrimethoxysilane residue, 3-mercaptopropyltriethoxysilane residue, 3-mercaptopropylmethyldimethoxysilane residue, 3-mercaptopropylmethyldisilane Alkoxysilane residue containing a mercapto group such as Tokishishiran residues can be exemplified.
The organic-inorganic hybrid particles of the present invention can have one or more of these polymerizable silicon compound residues.

The number of polymerizable silicon compound residues shown in Formula (2) is 1 to 200 in the particles, preferably 1 to 100, and more preferably 1 to 50.
The mass ratio between the polymerizable silicon compound residue and the silicic acid structural unit is an appropriate ratio in consideration of film performance such as photocurability, thermosetting, adhesion to the substrate, and storage stability in the dispersion. Specifically, it is preferable to have 0.5 to 20 parts by mass of a polymerizable silicon compound residue with respect to 1 part by mass of a silicate structural unit, and 1 to 10 parts by mass of a polymerizable silicon compound. It is more preferable to have a residue, and it is particularly preferable to have 3 to 8 parts by mass of a polymerizable silicon compound residue. From the same point, the number of polymerizable silicon compound residues bonded to the silicic acid structural unit is preferably 1 to 20, more preferably 1 to 10, and still more preferably. Is 1-6.

The organic-inorganic hybrid particles of the present invention are small-sized particles in which an organic component and an inorganic component are mixed, and the particle size is usually 1 nm to 200 nm, and many particles are 30 nm to 100 nm.
As will be described later, the timing of adding the polymerizable alkoxysilane compound to the active silicic acid solution is delayed or the hydrolysis of the polymerizable alkoxysilane compound is slowed to accelerate condensation of the active silicic acid to some extent. Suppressing the binding of hydrolyzed products to active silicic acid results in a large proportion of silicic structure, resulting in the formation of particles with a large particle size, conversely promoting the binding of hydrolyzed products of alkoxysilane compounds to active silicic acid. Then, the ratio of the polymerizable silicon compound residue is large, and particles having a small particle size are formed.
Examples of the former include organic-inorganic hybrid particles in which the ratio of the number of silicic acid structural units to the number of polymerizable silicon compound residues is 1: 1 to 1: 3 and the particle diameter is 100 nm to 200 nm. . As an example of the latter, the ratio of the number of silicic acid structural units and the number of polymerizable silicon compound residues is 1: 4 to 1:10, preferably 1: 4 to 1: 6, and the particle diameter is 1 nm to Organic-inorganic hybrid particles having a thickness of 100 nm, preferably 1 nm to 50 nm can be mentioned.

Below, the example of the organic inorganic hybrid particle | grains of this invention is shown.

  The coating composition in the present invention contains the organic-inorganic hybrid particles described above. Typically, it is a composition in which organic-inorganic hybrid particles are dispersed in a medium, and may contain a polyfunctional oligomer, an ultraviolet curable polymer, a solvent, an ultraviolet absorber, a light stabilizer, etc. depending on the intended performance. .

Polyfunctional oligomers have high photocuring properties due to ultraviolet rays and the like, and are easily copolymerized with organic-inorganic hybrid particles and ultraviolet ray curable polymers described later with energy rays such as ultraviolet rays, so the hardness of the film formed by photocuring is adjusted. Therefore, it is preferable to include an appropriate amount. In the present specification, “polyfunctional oligomer” means a molecular weight having two or more radical polymerizable functional groups such as vinyl group, acryloyl group, methacryloyl group, acryloyloxy group, methacryloyloxy group and mercapto group (SH). (MW) An organic compound capable of radical polymerization of about 200 to 1000 is meant. Examples of such polyfunctional oligomers include polymethylolpropane tri (meth) acrylate, tripropylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (meth). ) Acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, pentaerythritol tetra (meth) acrylate, Dipentaerythritol penta (meth) acrylate, tripentaerythritol octa (meth) acrylate, tetrapentaerythritol deca (meth) acrylate Rate, isocyanuric acid tri (meth) acrylate, isocyanuric acid di (meth) acrylate, polyester tri (meth) acrylate, polyester di (meth) acrylate, bisphenol di (meth) acrylate, diglycerin tetra (meth) acrylate, adamantyl di ( Examples include (meth) acrylate oligomers such as (meth) acrylate, isobornyl di (meth) acrylate, dicyclopentane di (meth) acrylate, and tricyclodecane di (meth) acrylate, and these are used alone or in combination of two or more. Modifications such as ethylene oxide, propylene oxide, and caprolactone may be made.
These polyfunctional oligomers may be blended in a large amount when it is necessary to increase the hardness of the film formed by photocuring, and may be reduced when it is desired to keep the hardness of the film low. Specifically, in the former case, the polyfunctional oligomer is preferably contained in an amount of 20% to 70% by weight, more preferably 30% to 50% by weight. On the other hand, in the latter case, the polyfunctional oligomer is preferably contained in the composition in an amount of 5% by weight to 50% by weight, and more preferably 10% by weight to 30% by weight.
The polyfunctional oligomer is not particularly limited as long as it can be polymerized with energy rays such as ultraviolet rays, but it is a 3-6 functional oligomer in terms of good copolymerizability with organic-inorganic hybrid particles during light irradiation. Are preferred, and hexafunctional oligomers such as dipentaerythritol penta (meth) acrylate are particularly preferred.
In the present specification, “(meth) acrylate” refers to methacrylate or acrylate.

The photocurable polymer can also be included for the purpose of relaxing the curing strain of the coating film to be formed and improving the flexibility.
In the present specification, the “photo-curable polymer” means an organic compound having a radical polymerizable functional group and a molecular weight (MW) of about 5000 or more.
A (meth) acrylic polymer is preferable for relaxation of curing strain, and a urethane-based polymer is preferable for flexibility. (Meth) acrylic urethane polymer is preferred to achieve both curing strain and flexibility. Particularly, the main chain composed of (meth) acrylic polymer is composed of urethane polymer, (meth) acrylic urethane oligomer and (meth) acrylic urethane polymer. A (meth) acrylurethane polymer in which a side chain consisting of one or more selected from the above is added by a urethane bond is preferred.
When a polymerizable urethane polymer or oligomer is blended singly, a problem may occur due to curing strain when a film is formed on a film-shaped molded article, but these are added to a rigid (meth) acrylic polymer. When a structure in which a urethane component is bonded is used, curing strain due to the urethane component is reduced. In addition, when a polymerizable urethane polymer or oligomer is blended singly, if there is an unreacted polymer or oligomer in the curing reaction, these may cause a reduction in scratch resistance. ) By being connected to an acrylic polymer, it becomes difficult to cause a reduction in scratch resistance even when it is unreacted.

  In the (meth) acrylic urethane-based polymer, the hydroxyl group-containing acrylic polymer of the main chain and the urethane polymer of the side chain are linked through a reaction between a hydroxyl group in the acrylic polymer and an isocyanate group such as the urethane polymer. In the present invention, it is preferable to have two or more side chains such as urethane polymer with respect to one acrylic polymer in terms of enhancing the flexibility of the formed film, and more preferably 5 or more. The above is more preferable. In addition, from the same point, it is preferable to have one or more polymerizable functional groups at the side chain, typically at the end of the side chain, and in some other positions.

  Examples of the (meth) acrylic polymer constituting the main chain include methyl methacrylate, butyl methacrylate, cyclohexyl methacrylate, isobornyl methacrylate benzyl methacrylate, and dicyclopentanyl methacrylate. These polymers are preferably selected in consideration of adhesion to various substrates. For example, methyl methacrylate is preferable for polyterephthalate (PET) substrates, and polycarbonate (PC) substrates are preferable. On the other hand, cyclohexyl methacrylate is preferred.

  The molecular weight (MW) of the (meth) acrylic polymer constituting the main chain is not particularly specified, but is preferably 3,000 to 300,000 from the viewpoint of reduction of curing strain, etc., and 5,000 to 200. Is more preferably 8,000, and further preferably 8,000 to 120,000. When the molecular weight is 3,000 or less, the effect of alleviating shrinkage at the time of curing may not be sufficiently exhibited, which may cause a decrease in adhesion and weather resistance due to curing strain. When the molecular weight is 300,000 or more, gelation may occur during the addition reaction of the acrylic urethane oligomer and the acrylic urethane polymer, and the reactivity of the ultraviolet curable acrylic urethane polymer during ultraviolet curing is likely to deteriorate.

  An acrylic urethane oligomer is a urethane structural unit linked to a main chain composed of a (meth) acrylic polymer by a urethane bond, has one or more (meth) acrylic groups, and has a molecular weight of less than 2,000. Similarly, an acrylic urethane polymer is a urethane structural unit linked to a main chain composed of a (meth) acrylic polymer by a urethane bond, has one or more (meth) acrylic groups, and has a molecular weight of 2,000 or more. .

Among these urethane structural units, acrylic urethane oligomers have relatively high reactivity and are the most involved sites for polymerization by photocuring, but their contribution in terms of improving flexibility is small. On the other hand, the acrylic urethane polymer has a relatively low reactivity and a relatively small contribution to polymerization by photocuring, but is the most contributing site in terms of improving flexibility. Therefore, it is preferable to adjust the ratio between the two in consideration of the desired hardness and flexibility balance of the coating film to be formed.
For example, when forming a high-hardness film, it is preferable that the side chain is composed only of an acrylic urethane oligomer or that the acrylic urethane oligomer is 5 to 10 times or more of the acrylic urethane polymer. On the contrary, when forming a highly flexible film, it is preferable that the side chain is composed only of an acrylic urethane polymer, or the acrylic urethane polymer is 2 to 5 times the acrylic urethane oligomer.

  As the acrylic urethane oligomer, those obtained by reacting (meth) acrylate containing a hydroxyl group with diisocyanate can be used. For example, 2-hydroxyethyl acrylate adduct of isophorone diisocyanate, 2-hydroxyethyl acrylate adduct of hexamethylene diisocyanate, toluene Examples include 2-hydroxyethyl acrylate adduct of diisocyanate, 2-hydroxyethyl acrylate adduct of methylene bisphenyl diisocyanate, 2-hydroxyethyl acrylate adduct of xylene diisocyanate, 2-hydroxyethyl acrylate adduct of dicyclohexylmethane diisocyanate, and the like. it can. The molecular weight (MW) of the acrylic urethane oligomer is more preferably 1,000 or less from the viewpoints of the above-mentioned improvement in photocuring reactivity and improvement in film hardness.

  As the acrylic urethane polymer, for example, a reaction product of diisocyanate and diol reacted with a hydroxyl group-containing (meth) acrylate can be used. Examples of the diisocyanate include isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HDI), toluene diisocyanate (TDI), methylenebisphenyl diisocyanate (MDI), xylene diisocyanate (XDI), and dicyclohexylmethane diisocyanate (HMDI). .

Examples of the diol include polyether diol, polycarbonate diol, polyester diol, 1,6-hexanediol, 1,5-pentanediol, 1,12-dodecanediol, and the like.
Examples of the hydroxyl group-containing (meth) acrylate include 2-hydroxy (meth) acrylate 4-hydroxybutyl (meth) acrylate, polyethylene glycol mono (meth) acrylate, polypropylene glycol mono (meth) acrylate, and polyethylene glycol mono (meth) acrylate. , Polypropylene glycol mono (meth) acrylate, pentaerythritol tri (meth) acrylate, and the like.
The molecular weight (MW) of the acrylic urethane oligomer is preferably from 2,000 to 50,000, preferably from 3,000 to 20,000, from the viewpoint of preventing the above-described improvement in flexibility, solvent resistance, and steel wool properties. 000 is more preferable, and 5,000 to 10,000 is more preferable.
Further, from the viewpoint of balance between flexibility, photocuring reactivity and hardness, the difference in molecular weight between the urethane structural units is preferably 1000 to 20,000, and more preferably 2000 to 10,000.

  The coating composition in the present invention can contain various components contained in conventional hard coat compositions, such as a film-forming aid (high boiling point solvent), an antifoaming agent, an ultraviolet absorber, and an ultraviolet ray. Absorbing monomers, light stabilizers, photopolymerization initiators, and the like can be included.

  Examples of the antifoaming agent include hydrophobic silica-based, metal cough soap-based, amide-based, polyether-based, and modified silicon-based, and these antifoaming agents are usually 0.01 to 1.0. It is contained in the range of mass%.

  Examples of the ultraviolet absorber include benzophenone, dibenzoylmethane, benzotriazole, salicylic acid, paraaminobenzoic acid, cinnamic acid, urocanic acid, triazine, and the like. Usually, it is added in the range of 0.1 to 10% by mass. Examples of the benzophenone-based ultraviolet absorber include 2,4-dihydroxybenzophenone, 2,2-dihydroxy4,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4methoxy-4-methylbenzophenone. 2-hydroxy-4-methoxybenzophenone, 4-phenylbenzophenone, 2-ethylhexyl 4-phenylbenzophenone-2-carboxylate, 2-hydroxy-4-n-octoxybenzophenone, 4-hydroxy-3-carboxybenzophenone, etc. Is mentioned. Examples of the dibenzoylmethane-based absorbent include butylmethoxydibenzoylmethane and 4-methoxy-4-t-butylphenylbenzoylmethane. Examples of the benzotriazole-based ultraviolet absorber include 2,2-hydroxy-5-methylphenylbenzotriazole, 2- (2-hydroxy-5-t-octylphenyl) benzotriazole, and the like. Examples of salicylic acid-based ultraviolet absorbers include menthyl salicylate, amyl salicylate, octyl salicylate, phenyl salicylate, benzyl salicylate, p-isopropanol phenyl salicylate, and amyl salicylate. Paraaminobenzoic acid-based ultraviolet absorbers include, for example, paraaminobenzoic acid, octyldimethylbenzoic acid, glycerylparaaminobenzoic acid, ethyldihydroxypropylparaaminobenzoic acid, ethyl N-ethoxylate paraaminobenzoate, methyl paradimethylaminobenzoate, or Examples thereof include 2-ethylhexyl paradimethylaminobenzoate. Cinnamic acid UV absorbers include octylmethoxycinnamate, ethyl-4-isopropylcinnamate, ethyl-2,4-diisopropylcinnamate, methyl-2,4-diisopropylcinnamate, n-propyl-p-methoxy. Examples include innamate, isopropyl-p-methoxycinnamate, isoamyl-p-methoxycinnamate, 2-ethylexyl-p-methoxycinnamate, 2-ethoxyethyl-p-methoxycinnamate, or cyclohexyl-p-methoxycinnamate. It is done. Examples of urocanic acid-based ultraviolet absorbers include urocanic acid or ethyl urocanate. Examples of triazine-based ultraviolet absorbers include bisresorcinyl triazine. The composition of this invention can contain the 1 type (s) or 2 or more types of the said ultraviolet absorber according to the objective.

  Examples of the UV-absorbing monomer include the above-mentioned benzotriazole-based, dibenzoylmethane-based, benzophenone-based, salicylic acid-based, paraaminobenzoic acid-based, cinnamic acid-based, and urocanic acid-based organic ultraviolet absorbers, acryloxy group, methacryloxy group And UV-absorbing monomers to which a radically polymerizable group such as a styryl group, an allyl group, a vinylbenzyl group, a vinyl ether group, an acrylamide group, a vinylalkylsilyl group or a vinylketone group is added.

  Examples of the light stabilizer include hindered amines and hindered phenols. These light stabilizers are usually added in the range of 0.1 to 10% by mass.

  Examples of the photopolymerization initiator include 2,2-dimethoxy-1,2-diphenylethane-1-one, 1-hydroxy-cyclohexyl-phenyl-ketone, 2-hydroxy-2-methyl-1-phenyl-propane- 1-one, 1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propan-1-one, 2-hydroxy-1- {4- [4- (2- Hydroxy-2-methyl-propionyl) -benzyl] phenyl} -2-methyl-propan-1-one, phenyl-glyoxylic-acid-methyl-ester, 2-methyl-1- (4-methylthiophenyl) -2 -Morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1,2- (dimethyla C) alkylphenone photopolymerization initiators such as 2-) [2-((4-methylphenyl) methyl] -1- [4- (4-morpholinyl) phenyl] -1-butanone, 2,4,6-trimethylbenzoyl- Acylphosphine oxide photopolymerization initiators such as diphenyl-phosphine oxide and bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, bis (η5-2,4-cyclopentadien-1-yl) -Bis (2,6-difluoro-3- (1H-pyrrol-1-yl) -phenyl) titani, titanocene photopolymerization initiators such as 784, 1.2-octanedione, 1- [4- (phenylthio) -, 2- (O-benzoyloxime)], ethanone, 1- [9-ethyl-6- (2-methylbenzoyl) -9H-carbazole-3-i Ru]-, 1- (0-acetyloxime), oxyphenylacetic acid, 2- [2-oxo-2-phenylacetoxyethoxy] ethyl ester and oxyphenylacetic acid, 2- (2-hydroxyethoxy) ethyl ester, However, it is not limited to these. The polymerization initiator can be used alone or in combination of two or more, and is preferably used in an amount of 0.01 to 10% by weight, preferably 0.1 to 5% by weight, based on the total amount of the monomer mixture. More preferably, it is used in an amount.

  The coating composition in the present invention may contain colloidal silica or colloidal silica modified with a silane coupling agent having a radical polymerizable functional group as another component for increasing the hardness of the formed film.

Although there is no restriction | limiting in particular about the solvent for the coating composition of this invention, It is preferable that the said hybrid particle is included in an organic solvent in consideration of the leveling property at the time of coating, and the wettability to a base material.
Examples of the solvent include alcohol solvents such as methanol, ethanol, normal propyl alcohol, isopropyl alcohol, and propylene glycol monomethyl ether, acetone solvents such as methyl ethyl ketone ketone and methyl isobutyl ketone, and ester solvents such as ethyl acetate and butyl acetate. A solvent, aromatic solvents such as toluene and xylene can be mentioned, and a point alcohol solvent having good solubility of organic and inorganic particles is preferable, and propylene glycol monomethyl ether is particularly preferable.

The coating composition of the present invention described above can be used for providing a protective layer on various resin molded products.
For example, a coating film can be formed by applying the coating composition of the present invention to a substrate and irradiating it with energy rays to cure. In this photocuring, a film is formed by polymerization reaction of radically polymerizable functional groups, and in the particles of the present invention in which an organic component and an inorganic component are mixed, a highly flexible film is formed with high adhesion to the substrate. . For this reason, even if it extends and bends in the state which formed the film in the film-shaped molded article, it is hard to produce crack. The intermediate product or member on which the film is formed by photocuring can be transferred and subjected to the next thermal curing by another main body.

  After photocuring the coating composition of the present invention, heat treatment may be performed as necessary. The organic-inorganic hybrid particles of the present invention have many functional groups such as silanol groups even after photocuring, a condensation reaction occurs by heat treatment, and a crosslinked structure is formed within and between the particles, resulting in extremely high resistance. A protective film having scratch resistance and hardness can be formed. An apparatus having such a protective film is superior in terms of these characteristics to a protective film formed by conventional photocuring.

  The coating composition of the present invention is not particularly limited with respect to the type of substrate to be applied, and may be used by changing the composition according to the type of substrate. For example, it can be used for a substrate made of polyethylene terephthalate (PET), polycarbonate (PC), acrylic (PMMA), polystyrene (PS), ABS, or vinyl chloride resin.

2. Next, a method for producing organic-inorganic hybrid particles of the present invention will be described.

  The organic / inorganic hybrid particles of the present invention are prepared by adding an aqueous solution of active silicic acid such as a vinyl group, an acryloylalkyl group, a methacryloylalkyl group, an acryloyloxyalkyl group, a methacryloyloxyalkyl group, and / or a mercaptoalkyl group (SH). It can be produced by adding a polymerizable alkoxysilane compound having a radically polymerizable functional group and silane coupling them.

  Activated silicic acid can be obtained by a conventional method, but the method of the present invention is to obtain active silicic acid by removing metal (for example, sodium) from an aqueous solution of a metal salt of silicic acid such as water glass. Is convenient to carry out

The metal salt of silicic acid refers to a compound in which at least a part of OH or the like of silicic acid is a salt represented by O ⁻ R ⁺ (wherein R ⁺ represents a metal cation). For example, orthosilicic acid Sodium, potassium orthosilicate, sodium orthosilicate (Na ₄ SiO ₄ ), potassium orthosilicate (K ₄ SiO ₄ ), magnesium orthosilicate (Mg ₂ SiO ₄ ), beryllium orthosilicate (Be ₂ SiO ₄ ), olivine ( (Fe, Mg) ₂ SiO ₄ ), garnet group (Mg ₃ Al ₂ Si ₃ O ₁₂ , Ca ₃ Al ₂ Si ₃ O ₁₂ ), zircon (ZrSiO ₄ ), syenite, wilstone, lanthanum, mul Stones, topaz, cruciform stones, sapphirine, norbergite, chondrite, fume stone, monoclinic fume stone kusabi stone, chloritoid, etc. ) Silicates: Solosilicates such as plagioclase group, chlorite group, Lawsonite, Panberry stone, etc .; Cyclosilicates such as quinnite, tourmaline, beryl, feldspar, feldspar, zeolites, etc. Tectosilicate; inosilicate; lithium metasilicate (Li ₂ SiO ₃ ), sodium metasilicate (Na ₂ SiO ₃ ), potassium metasilicate (K ₂ SiO ₃ ), magnesium metasilicate (MgSiO ₃ ), sodium calcium metasilicate (Na ₂ SiO ₃ —CaSiO ₃ ), calcium metasilicate (CaSiO ₃ ), magnesium calcium silicate (CaMgSi ₂ O ₅ ), barium metasilicate (BaSiO ₃ ), manganese metasilicate (MnSiO ₃ ), iron metasilicate (FeSiO ₃ ), cobalt metasilicate (CoSiO ₃ ), Metasilicates such as lead metasilicate (PbSiO ₃ ), CaMgSi ₂ O ₆ -MgSi ₂ O ₆ solid solution, CaMgSi ₂ O ₆ -FeSi ₂ O ₆ solid solution; phyllosilicates such as muscovite group and biotite group It is done.

といった種々の構造を有する化合物を含むことが知られている（非特許文献１）。 An aqueous solution of a metal silicate usually contains metal silicates having various structures. For example, an aqueous solution of sodium silicate is:

It is known to contain compounds having various structures such as (Non-patent Document 1).

［式中、ｎは、１〜５の整数であり、Ｒ^１６、Ｒ^１７、Ｒ^１８及びＲ^１９は、それぞれ独立して、Ｏ⁻、ＯＨ、又はＯ⁻Ｒ^１１＋（式中、Ｒ^１１は、Ｌｉ、Ｎａ又はＫである）であるか、或いはＲ^１６及びＲ^１７、又はＲ^１８及びＲ^１９の１以上の対は、１つのＯであり、Ｒ^１６、Ｒ^１７、Ｒ^１８及びＲ^１９の少なくとも１つは、Ｏ⁻Ｒ^１１＋である］
で表される化合物が好ましく、下記式

［式中、Ｒ^２０からＲ^２７は、それぞれ独立して、Ｏ⁻、ＯＨ、又はＯ⁻Ｒ^１１＋（式中、Ｒ^１１は、Ｌｉ、Ｎａ又はＫである）であるか、或いはＲ^２０及びＲ^２１、Ｒ^２２及びＲ^２３、Ｒ^２４及びＲ^２５、並びにＲ^２６及びＲ^２７の各対は、それぞれ独立して１つのＯであってもよく、それぞれＲ^２０からＲ^２５、又はＲ^２０からＲ^２７の少なくとも１つは、Ｏ⁻Ｒ^１１＋である］で表される化合物がより好ましく、上記６員環の化合物が特に好ましい。 In the present invention, as described above, since it is easy to control the reaction between the active silicic acid and the polymerizable alkoxysilane compound, it is preferable to react the active silicic acid having a cyclic structure with the radical polymerizable alkoxysilane compound. The acid metal salt preferably has a structure corresponding to it. Among these, a cyclic structure having 2 to 8 silicon atoms is preferable, a cyclic structure having 2 to 6 silicon atoms is more preferable, and a cyclic structure having 3 to 5 silicon atoms is particularly preferable.
The silanol group of active silicic acid having a cyclic structure is less reactive than the chain structure, so the reaction pH, the timing of administration of the polymerizable alkoxysilane compound after preparation of the active silicic acid, the active silicic acid and the polymerizability The reaction between the activated silicic acid and the hydrolysis of the polymerizable alkoxysilane compound can be easily controlled by the molar ratio of the alkoxysilane compound, and it becomes easy to obtain organic-inorganic hybrid particles having a desired particle size.
In the preparation of organic / inorganic hybrid particles, those having a cyclic structure are preferred because the reaction between the active silicic acid and the polymerizable alkoxysilane compound is easy to control.

[In the formula, n is an integer of 1 to 5, and R ¹⁶ , R ¹⁷ , R ¹⁸ and R ¹⁹ are each independently O ⁻ , OH, or O ⁻ R ¹¹⁺ (wherein R ¹¹ represents Or one or more pairs of R ¹⁶ and R ¹⁷ , or R ¹⁸ and R ¹⁹ is one O, R ¹⁶ , R ¹⁷ , R ¹⁸ and R ^19. At least one of is O ⁻ R ¹¹⁺ ]
Is preferably a compound represented by the following formula:

[Wherein R ²⁰ to R ²⁷ are each independently O ⁻ , OH, or O ⁻ R ¹¹⁺ , wherein R ¹¹ is Li, Na, or K, or R ²⁰ and Each pair of R ²¹ , R ²² and R ²³ , R ²⁴ and R ²⁵ , and R ²⁶ and R ²⁷ may independently be one O, each from R ²⁰ to R ²⁵ , or R ²⁰ At least one of R ²⁷ is O ⁻ R ¹¹⁺ ], and the above 6-membered ring compound is particularly preferable.

Conveniently, an aqueous solution of sodium silicate marketed as so-called water glass usually contains the above-mentioned silicate compound having a cyclic structure, which is convenient to use. Examples of commercially available aqueous solutions of sodium silicate include JIS No. 1 sodium silicate, JIS No. 2 sodium silicate, and JIS No. 3 sodium silicate. Among them, the content of sodium is small, and the deionization step can be performed efficiently. JIS No. 3 sodium silicate is preferable in that it can be used. On the other hand, from the viewpoint of increasing the number of functional groups such as O ⁻ and OH per silicon number, JIS No. 1 sodium silicate may be used.

  By conducting treatments such as electrodialysis and reverse osmosis membranes for aqueous solutions containing metal silicates with multiple structures such as commercially available water glass, the concentration of compounds with preferred structures can be increased or purified. Also good.

  The aqueous solution of a metal salt such as an alkali metal salt of silicic acid used in the present invention is a solution in which a metal salt of silicic acid is typically dissolved in water, preferably ion-exchanged water. However, an acid such as sulfuric acid, hydrochloric acid, formic acid or acetic acid may be added as necessary.

  The removal of the metal salt can be performed by a method of treating in a strong acid aqueous solution, a method of treating with an ion exchange resin, or a combination thereof.

In the case of treating with a strong acid, an active silica is added by adding an aqueous solution of a metal silicate to an aqueous solution containing 0.8 to 2.0 equivalents of acid relative to 1 equivalent of metal ions in the aqueous solution of metal silicate. An acid is obtained.
When the amount of acid is 0.8 or less, removal of metal ions tends to be insufficient, and when the amount of acid is 2.0 or more, acid tends to remain, and the number of operations such as washing and purification increases. It is not preferable. The type of strong acid is not particularly limited as long as it can remove metal ions, but hydrochloric acid, sulfuric acid, and nitric acid are preferable. When a volatile acid is used, hydrochloric acid is most preferable because there is little remaining of the acid, and the curability is hardly lowered during the condensation reaction of the silanol groups of the organic-inorganic hybrid particles.

When active silicic acid is obtained by ion exchange treatment, it is preferable to remove metal ions by treating an aqueous solution of a metal salt of silicic acid with a cation exchange resin.
The aqueous solution of the metal silicate salt is preferably prepared at a concentration of 2 to 15% by mass from the viewpoint of removal efficiency of metal ions at the time of ion exchange, and a solution can be prepared at a concentration of 4 to 8% by mass. More preferred.

  In the present invention, a general cation exchange resin can be used. For example, a resin having a functional group such as a sulfonic acid group or a carboxyl group can be used, and a resin having a sulfonic acid group is particularly preferable. . Examples of commercially available cation exchange resins include those manufactured by Mitsubishi Rayon Co., Ltd., strong acid cation exchange resin gel type diamond ion SK104, SK1B, SK110, SK12, porous type diamond ions PK208, PK212, PK216, PK218, PK220, PK228, and the like. It is done.

In the ion exchange treatment, for example, first, a strongly acidic cation exchange resin is placed in ion exchange water, an aqueous hydrochloric acid solution is added thereto, and the mixture is sufficiently stirred, and then the ion exchange resin is filtered to perform the acid treatment. Next, the treated ion exchange resin is washed with ion exchange water, and the washed ion exchange resin is added to the silicate aqueous solution in the same amount as the silicate, and the silicate is brought into contact with the ion exchange resin for ion exchange. What is necessary is just to process.
The timing for taking out the ion exchange resin is preferably determined based on the pH. Specifically, the ion exchange resin is preferably separated when the treatment solution reaches pH 2 to 5, and more preferably pH 2 to 4. .
This pH range indicates that most of the metal ions have been removed from the silicate to become O-, and when a treatment liquid from which the ion exchange resin is taken out in this numerical range is used, more alkoxylane compounds and It can be reacted and the resulting particles can have more functional groups.

  When the metal ions are removed by the ion exchange treatment, the aqueous solution of active silicic acid rapidly gels by a condensation reaction to produce a silane compound in which a large number of silicic acids are polymerized. For this reason, in order to obtain composite particles having a low molecular weight (ideally without any polymerization) and having a large number of alkoxysilane functional groups per number of silicon, as soon as possible after ion exchange treatment, an aqueous solution of active silicic acid is added. It is preferable to add an alkoxylane compound having a radically polymerizable functional group. Specifically, it is preferable to add the alkoxylane compound having a radical polymerizable functional group in a time shorter than 10 hours after the ion exchange treatment, and the alkoxylane compound having a radical polymerizable functional group is added within 5 hours after the ion exchange treatment. More preferably, an alkoxylane compound having a radical polymerizable functional group is added within 3 hours after the ion exchange treatment, and an alkoxylane compound having a radical polymerizable functional group is added within 1 hour after the ion exchange treatment. It is particularly preferred to add.

  In the present invention, the alkoxylane compound added to the aqueous solution of active silicic acid may be any compound containing a carbon chain having a radical polymerizable functional group and having a structure in which an alkoxyl group is bonded to silicon. A group in which a (meth) acrylic group, a (meth) acryloxy group, or a mercapto group is bonded to a carbon chain having 2 to 10, preferably 2 to 5, more preferably 2 to 3 carbon atoms, and at least one (typically A typical example is a compound having a structure in which an alkoxyl group having 1 to 5 carbon atoms and optionally an H and / or OH group are bonded to Si. More specifically, for example, methacryloxypropyltrimethoxysilane, 3-acryloxypropylmethyldimethoxysilane, 3-acryloxypropyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane and the like can be mentioned. Examples of the alkoxysilane compound contained include 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropylmethyldimethoxysilane, and 3-mercaptopropylmethyldimethoxysilane. These compounds are used alone. Or they can be used in combination.

The mass ratio between the polymerizable alkoxylane compound and the active silicic acid is in consideration of the characteristics of the protective film such as scratch resistance, hardness, photocuring property and ultraviolet curing property, and the storage stability of the coating composition. A preferable range may be selected as appropriate, but it is usually 0.5: 1 to 20: 1, preferably 1: 1 to 10: 1, and more preferably 1: 1 to 8: 1.
From the same viewpoint, the polymerizable alkoxysilane is preferably added at a molar ratio of alkoxysilane to active silicic acid (active silicic acid: alkoxysilane) at a ratio of 1: 1 to 1:20, preferably at a ratio of 1 to 10 It is more preferable to add, and it is still more preferable to add in the ratio of 1-6.

  However, the organic-inorganic hybrid particles of the present invention can have a more specific particle size distribution by controlling the particle size by changing the conditions for the condensation reaction between the active silicic acid and the alkoxysilane compound. Specifically, after the active silicic acid is prepared, the time until the alkoxysilane compound is added, the ratio of the two components is changed, the pH of the alkoxysilane compound solution or reaction solution is changed, and the like. The particle size can be controlled by controlling the decomposition rate. For example, when it is desired to reduce the particle size, these conditions may be set such that the reaction between the active silicic acid and the alkoxysilane compound takes precedence over the condensation reaction between the active silicic acids. More specifically, after preparing the active silicic acid, the alkoxysilane compound is added within 1 hour. In some cases, an inorganic acid is further added to the reaction solution to adjust the pH to 2 or less. The conditions are such that silanolization of the silane compound is promoted. Moreover, 3-20 molecules, more preferably 5-20 molecules of an alkoxysilane compound are made with respect to 1 molecule of active silicic acid. Moreover, it is preferable to complete the reaction in a short time by raising the temperature. Specifically, for example, the reaction temperature is 20 ° C. to 60 ° C., preferably 40 ° C. to 50 ° C., and the reaction is performed for 10 minutes to 120 minutes, preferably 30 minutes to 60 minutes.

  On the other hand, if it is desired to increase the particle size, the reaction rate between the active silicic acid and the alkoxysilane compound may be slowed, but if the reaction rate is too slow, the active silicic acid and alkoxysilane compounds react with each other, In some cases, particles containing both organic and inorganic components cannot be obtained. For this reason, it is preferable to adjust pH to 2-6, and it is better to adjust to pH = 3-5. Moreover, on this condition, it is preferable to react 1-6 molecules of a polymerizable silicon compound with respect to 1 molecule of activated silicic acid (A), and it is more preferable to react 1-4 molecules. In order to enlarge the particles, it is preferable to react at a relatively low temperature for a relatively long time. Specifically, for example, the reaction temperature is 0 ° C. to 40 ° C., preferably 20 ° C. to 30 ° C., and the reaction is performed for 60 minutes to 240 minutes, preferably 90 minutes to 150 minutes.

  As a solvent in the condensation reaction of the active silicic acid and the polymerizable alkoxysilane compound, water is preferable, but a small amount of alcohol may be contained. In a solvent to which only water and a small amount of alcohol are added, the organic-inorganic hybrid particles are precipitated and settled at a stage where they have grown to a particle size of a certain size or more, so that particles of a uniform size can be obtained and recovered easily. At this time, when alcohol is added, the solubility of both components is increased and the molecular weight of the precipitated organic-inorganic particles is increased, so that the particle diameter can be increased.

The recovered particles can be dried and then placed in a solvent to form a coating composition. The solvent is preferably an organic solvent in consideration of leveling properties during coating and wettability to the substrate. For example, alcohol solvents such as methanol, ethanol, normal propyl alcohol, isopropyl alcohol, propylene glycol monomethyl ether, acetone, and methyl ethyl ketone ketone. Methyl isobutyl ketone ketone solvents, ester solvents such as ethyl acetate and butyl acetate, and aromatic solvents such as toluene and xylene can be used. Among them, an alcohol solvent having good solubility of the organic / inorganic particles is preferable, and propylene glycol monomethyl ether is particularly preferable.
As described above, this coating composition can contain various components.

  Hereinafter, the present invention will be described in more detail with reference to examples. However, the technical scope of the present invention is not limited by the description of the examples.

[Synthesis Example 1] Preparation of organic / inorganic hybrid particle C-1 To 100 g of No. 3 sodium silicate (manufactured by Tosoh Sangyo Co., Ltd.), 900 g of ion-exchanged water was added and stirred well. 500 g of strongly acidic cation exchange resin SK1B (manufactured by Mitsubishi Chemical Co., Ltd.) was added and slowly stirred for 30 minutes. After confirming that the pH of the solution was 3.8, the ion exchange resin was separated. Next, 10 g of a 10% aqueous hydrochloric acid solution was added with stirring to obtain a colorless and transparent aqueous solution of active silicic acid (A) having a pH of 1.4 and a non-volatile component of 4.0%. Immediately after that, 500 g of this aqueous solution of active silicic acid (A) was weighed into a container equipped with a stirrer and a condenser, and while stirring, the silane coupling agent KBE-503 (3-methacryloxypropyltriethoxysilane, manufactured by Shin-Etsu Chemical Co., Ltd.) 108 g was added and stirred at 40 ° C. for 40 minutes to obtain a white precipitate. After the formation of the precipitate, the mixture was further stirred for 1 hour, and the precipitate was filtered and dried to synthesize organic-inorganic hybrid particles (C-1). 30 g of the obtained organic-inorganic hybrid particles (C-1) were dissolved in 70 g of methyl ethyl ketone to obtain a reactive silica solution in which the heating residue was adjusted to 30%. When this silica was observed with an electron microscope, the particle size was about 30 nm and it was almost uniform.
The molar ratio of active silicic acid to silane coupling agent is about 1: 6, and the mass ratio is 1: 5.

[Synthesis Example 2] Preparation of organic-inorganic hybrid particle C-2
Strongly acidic cation exchange resin SK1B (Mitsubishi Chemical Corporation) that retains sulfonic acid groups in which sodium silicate group is replaced with sodium 5% aqueous solution by adding 900 g of ion exchange water to 100 g of No. 3 sodium silicate (manufactured by Tosoh Sangyo Co., Ltd.) 500 g) was added and stirred slowly for 30 minutes. After confirming that the pH of the solution was 3.8, the ion exchange resin was separated to obtain a colorless and transparent aqueous solution of active silicic acid (A) having a non-volatile component of 4.3%. Immediately, 500 g of this aqueous solution of active silicic acid (A) was weighed in a container equipped with a stirrer and a condenser, and while stirring, the silane coupling agent KBE-503 (3-methacryloxypropyltriethoxysilane, manufactured by Shin-Etsu Chemical Co., Ltd.) 21 0.5 g was added and stirred at 20 ° C. for 2 hours to obtain a white precipitate. After the formation of the precipitate, the mixture was further stirred for 1 hour, and the precipitate was filtered and dried to synthesize organic-inorganic hybrid particles (C-2). 30 g of the obtained organic-inorganic hybrid particles (C-2) were dissolved in 70 g of methyl ethyl ketone to obtain a reactive silica solution in which the heating residue was adjusted to 30%. When this silica was observed with an electron microscope, it was found to be a substantially uniform particle having a particle size of about 180 nm.
The molar ratio of activated silicic acid to silane coupling agent is about 1: 1, and the mass ratio is 1: 1. Please add.

[Synthesis Example 3] Preparation of organic / inorganic hybrid particle C-3 Colloidal silica IPA-ST (manufactured by Nissan Chemical Industries, Ltd.) 700 g and silane coupling agent KBE-503 (3-methacryloxypropyltriethoxysilane, manufactured by Shin-Etsu Chemical Co., Ltd.) ) 90 g, 3 g of alkoxy oligomer catalyst DX-9740 (manufactured by Shin-Etsu Chemical Co., Ltd.), 10 g of water and 200 g of isopropyl alcohol were added and stirred at 70 ° C. for 5 hours to obtain a dispersion of hybrid particles C-3.

[Synthesis Example 4] Synthesis of UV-curable acrylic urethane polymer AU (Synthesis of acrylic polymer A-1)
A flask equipped with a stirrer, a dropping funnel, a condenser and a thermometer was charged with 300 g of methyl isobutyl ketone (MIBK), heated to 110 ° C. under a nitrogen stream, 440 g of methyl methacrylate, 60 g of 2-hydroxyethyl methacrylate, A mixed solution of 3 g of azobisisobutyronitrile was charged into a dropping funnel, and the mixture was added dropwise at a constant rate over 2 hours. Next, 2 g of azobisisobutyronitrile and 100 g of methyl isobutyl ketone were charged into the dropping funnel and dropped at a constant speed over 2 hours. Thereafter, the mixture was aged for 3 hours and diluted with 100 g of methyl ethyl ketone (MEK) to synthesize a hydroxyl group-containing acrylic polymer (A-1). As a result of measuring the molecular weight of the obtained polymer, the weight average molecular weight was 126000, and the heating residue was 50.1%.

(Synthesis of acrylic urethane oligomer B-1)
A flask equipped with a stirrer, dropping funnel, condenser and thermometer was charged with 100 g of methyl isobutyl ketone, 318 g of isophorone diisocyanate (IPDI), 0.5 g of methoquinone and 0.05 g of dioctyltin, and the mixture was heated to 80 ° C. by mixing with nitrogen and oxygen Warmed and 182 g of 2-hydroxyethyl acrylate was added dropwise at a constant rate over 3 hours. Thereafter, aging was performed at 80 ° C. for 5 hours, and the reaction was completed when NCO% was 6 to 8%. Diluted with 400 g of methyl isobutyl ketone to synthesize an acrylic urethane oligomer (B-1) having an isocyanate group at one end and an acrylic group at the other end. As a result of measuring the molecular weight of the obtained oligomer, the weight average molecular weight was about 400, and the heating residue was 50.1%.

(Synthesis of acrylic urethane oligomer C-1)
A flask equipped with a stirrer, a dropping funnel, a condenser tube and a thermometer was charged with 300 g of methyl isobutyl ketone, 311 g of PTMG650 manufactured by Mitsubishi Chemical Co., Ltd., 139 g of hexamethylene diisoanate, and 0.05 g of dioctyltin. The temperature was raised to 80 ° C. and the reaction was allowed to proceed for 5 hours to obtain a urethane oligomer containing NCO% 6.2 at both terminal isocyanate groups. Next, 0.5 g of methoquinone and 50 g of 2-hydroxyethyl acrylate were added and reacted for another 3 hours, then diluted with 200 g of methyl isobutyl ketone, and one end was an isocyanate group and the other end was an acrylic urethane polymer. (C-1) was synthesized. As a result of measuring the molecular weight of the obtained polymer, the weight average molecular weight was about 7300, and the heating residue was 50.2%.

(Synthesis of UV curable acrylic urethane polymer AU)
In a flask equipped with a stirrer, a dropping funnel, a condenser tube and a thermometer, 700 g of a hydroxyl group-containing acrylic polymer (A-1), 150 g of an acrylic urethane oligomer (B-1), 150 g of an acrylic urethane polymer (C-1), and methoquinone 0 0.5 g and dioctyltin 0.05 g were charged, and the temperature was raised to 80 ° C. in a mixed air stream of nitrogen and oxygen, followed by reaction for 8 hours. After confirming the disappearance of the isocyanate group peak by FT-IR, the reaction was completed by diluting with 650 g of propylene glycol monomethyl ether. An ultraviolet curable acrylic urethane polymer (AU) was synthesized. As a result of measuring the molecular weight of the obtained polymer, the weight average molecular weight was 178,000, and the heating residue was 30.3%.

[Example 1]
While stirring 300 g of the dispersion liquid of organic / inorganic hybrid particles C-1, 10 g of DPHA was gradually added and stirred for 10 minutes to confirm that DPHA was dissolved. Then, 3 g of Irgacure 184 was added and further stirred for 10 minutes. Subsequently, it filtered with the filter paper No2 by Advantech, and prepared the composition for coating.

[Examples 2-7 and Comparative Examples 1-5]
A coating composition was prepared in the same manner as in the procedure described in Example 1 except that the compositions described in Tables 1 and 2 below were used.

[Evaluation]
The following evaluation was performed about each obtained composition.

(Elongation after UV curing)
Each composition was applied to a PET film with a bar coater so that the dry film thickness was 2 μm, dried at 80 ° C. for 1 minute, and then irradiated with ultraviolet rays of 1000 mJ / cm ² to prepare test pieces. The elongation of the test piece was measured at a tensile speed of 2 mm / min according to JIS 7161 using a tensile tester (Instron 5960 series). Elongation rate = (stretched length) / original length x 100

(Scratch resistance after heat curing, steel wool resistance)
Each composition was coated on a PET film with a bar coater so that the dry film thickness was 2 μm, dried at 80 ° C. for 1 minute, irradiated with 1000 mJ / cm ^{2 of} ultraviolet light, and then heated at 160 ° C. for 1 minute for testing. A coating was obtained. The test film was rubbed 100 times with a 500 g load using steel wool # 0000, and the number of scratches was confirmed visually.
Evaluation criteria:
◎ No scratch ○ Within 5 scratches △ Within 15 scratches × Within 30 scratches ×× More than 30 scratches

(Evaluation of pencil hardness after UV curing)
Each composition is formed on a glass plate with a bar coater so that the film thickness of the dried coating film is 2 μm, dried at 80 ° C. for 1 minute, and then irradiated with ultraviolet rays of 1000 mJ / cm ² to form a test coating film. Obtained. The hardness of this test coating was evaluated using a 6B to 9H pencil according to JIS 5600-5-4.

(Evaluation of pencil hardness after heat curing)
Each composition is formed on a glass plate with a bar coater so that the film thickness of the dried coating film becomes 2 μm, dried at 80 ° C. for 1 minute, irradiated with ultraviolet rays of 1000 mJ / cm ² , and then 1 at 160 ° C. A test coating was obtained by heating for a minute. The hardness of this test coating was evaluated using a 6B to 9H pencil according to JIS 5600-5-4.

(Evaluation of coating film appearance after thermosetting)
Each composition is formed on a glass plate with a bar coater so that the film thickness of the dried coating film is 2 μm, dried at 80 ° C. for 1 minute, and then irradiated with 1000 mJ / cm ² of ultraviolet rays using an ultraviolet irradiator. Then, the mixture was heated at 160 ° C. for 1 minute, cured at 25 ° C. for 1 day, and the turbidity of the coating film was visually confirmed.
Evaluation criteria ◎: Transparent and glossy ○: Transparent but gloss is slightly inferior △: Slightly cloudy gloss is slightly inferior ×: Turbidity and gloss is inferior ××: Heavy fog and strong gloss No

(Evaluation of substrate adhesion after thermosetting)
The composition obtained in each Example and Comparative Example was formed on each substrate of PET film, polycarbonate (PC), acrylic, ABS and polystyrene (PS) so that the dry coating film was 4 μm, After drying at 80 ° C. for 1 minute, 1000 mJ / cm ² ultraviolet rays were irradiated using an ultraviolet irradiator. Then, it heated at 160 degreeC for 1 minute, and cured at 25 degreeC for 1 day. About the obtained test piece, the adhesive tape peeling test by 100 grids of 1 mm x 1 mm was performed, and it evaluated by the number of grids remaining on the base material.
Evaluation criteria ◎: 100 pieces ○: 90 to 99 pieces Δ: 80 to 89 pieces ×: 70 to 79 pieces XX: 69 pieces or less

[Evaluation results]
Tables 3 and 4 collectively show the evaluation results in the respective tests of the coating films obtained with the respective compositions.

As described above, the composition of Example 1 does not contain the ultraviolet curable acrylic urethane polymer AU and contains a lot of hybrid particles, but the coating is transparent, and a coating with a good appearance is obtained. Was also good. The reason why such characteristics are obtained despite the high silica content is thought to be due to the structure of hybrid particles in which organic and inorganic components are mixed. That is, since the particle (c-1) is obtained by a condensation reaction between a low-molecular active silicic acid obtained from water glass and an alkoxysilane compound capable of ultraviolet curing, a structure in which organic and inorganic components are mixed inside the particle. This is considered to contribute to the transparency of the film and the adhesion to the equipment. On the other hand, the composition of Comparative Example 3 is a composition in which hybrid particles (c-3) modified with the same silane coupling agent are blended into colloidal silica instead of the particles (c-1). As a result, the adhesion to the substrate was poor. When colloidal silica is modified with a silane coupling agent, the inside of the particle is inorganic and the outside has a dual structure with organic, and the activity of colloidal silica is low, so there is little organic content that can be modified on the surface, and sufficient film-forming properties are achieved. It is thought that it cannot be obtained.
The composition of Example 2 contains the ultraviolet curable acrylic urethane polymer together with the hybrid particles (c-1), and the substrate adhesion and flexibility are improved as compared with the film formed of the composition of Example 1. doing. Further, although the hardness and scratch resistance were slightly lowered as compared with the film formed from the composition of Example 1, it was confirmed that it was still maintained at a high level. On the other hand, the compositions of Comparative Examples 1 and 2 are compositions in which colloidal silica and hybrid particles (c-3) obtained by modifying colloidal silica with a silane coupling agent are blended in place of particles (c-1). The transparency of the coating and the adhesion to the substrate were relatively good, but the scratch resistance was low, and there was little or no improvement due to the blending of the inorganic components. The hybrid particle (c-1) contains many active silanol groups in the particle. For this reason, it is considered that the heat treatment after the ultraviolet irradiation causes a silanol group condensation reaction to increase the crosslink density, which leads to a significant improvement in scratch resistance. On the other hand, colloidal silica does not have an active silanol group, and hybrid particles (C-3) obtained by modifying colloidal silica with a silane coupling agent only have an active silanol group brought in from the silane coupling agent. And many of them are consumed due to the modification of colloidal silica. For this reason, in the film formed with the composition of Comparative Example 2 containing colloidal silica (IPA-ST), no improvement in scratch resistance was observed, and the composition of Comparative Example 1 containing hybrid particles (C-3) It is understood that only a slight improvement in the scratch resistance was observed in the film formed in (1).
The composition of Example 3 contained hybrid particles (c-2) having many inorganic components and a large particle size, but the obtained coating had good coating appearance and substrate adhesion. Moreover, the scratch resistance and hardness of the coating were also at a high level. Such characteristics are also attributed to the fact that the particles have a structure in which organic and inorganic components are mixed.
The composition of Example 4 is the same as the composition of Example 2 except that instead of the hybrid particles (C-1), two types of hybrid particles (C-1) and (C-2) having different particle diameters are included. However, it was confirmed that the hardness was improved as compared with the film obtained with the composition of Example 2. Rather than using the same particle size, the use of reactive silica having two or more particle sizes results in a more uniform distribution of silica in the coating film, which improves co-polymerization with DPHA and the like. I think that the.
The composition of Example 5 and the composition of Comparative Example 4 are both the same composition except that they each contain hybrid particles (C-1) and hybrid particles (C-3). The coating obtained with the composition of Example 5 containing the hybrid particles (C-1) has better flexibility than the coating obtained with the composition of Comparative Example 4 containing the hybrid particles (C-3). As a result. Reactive silica (c-1) has a structure in which an inorganic component and an organic component are mixed, and the hybrid particle (c-1) itself has high flexibility, but the surface of the colloidal silica particle is modified with a silane coupling agent. This is probably because flexibility was not obtained in (c-3).
The composition of Example 6 contains a large amount of DPHA, which is a polyfunctional oligomer, but maintains good scratch resistance, hardness, and substrate adhesion with little distortion due to the curing reaction during ultraviolet irradiation. On the other hand, in Comparative Example 5, scratch resistance and hardness are reduced. The characteristic of the film obtained with the composition of Example 6 seems to be an effect due to the condensation reaction of silanol groups contained in the hybrid particles (c-1).
The composition of Example 7 contains the hybrid particles (c-1) but does not contain the UV curable acrylic urethane polymer and DPHA. The film formed with this composition had a film formed only of the hybrid particles (c-1), but the coating film appearance and substrate adhesion were good. The hybrid particles (c-1) are prepared by adding an alkoxysilane compound (B) immediately after preparing an aqueous solution of active silicic acid (A) having a pH of 3.8, and the active silicic acid (A) and the alkoxysilane compound ( It is understood that the hydrolyzate of B) reacted rapidly to form hybrid particles (c-1). As a result, it is considered that particles having a structure in which the silicic acid structural unit is small and the organic component and the inorganic component are not localized and are uniformly mixed are formed, and the above characteristics are considered to be due to such a structure.
In the pencil hardness test performed on the film after UV curing and heat curing, the film obtained with the composition of Examples 1 to 7 using silica (C-1) or (C-2) was cured after UV curing. In comparison, the hardness was significantly higher after heating. This is presumably because there are many active silanol groups even after UV curing, so that the condensation reaction of silanol groups occurred by heating, which increased cross-linking within and between particles. On the other hand, in the compositions of Comparative Examples 1 to 5 containing colloidal silica or silica (C-3) modified with polymerizable alkoxysilane, the hardness after heating was not changed at all or slightly increased. This indicates that silanol groups are not present or very little if present, and are not sufficient to increase the hardness by heat treatment.

Claims (15)

Following formula (1)

[Wherein, a is an integer of 1 to 5, and R ¹ , R ² , R ³ and R ⁴ are each independently O−, O ⁻ , OH, or O ⁻ Na ⁺ , Or R ¹ and R ² , or R ³ and R ⁴ are one O]
Following formula (2)

[In the formula (2), one or two of R ^{5 to} R ⁷ are each independently a vinyl group, a vinyl group-containing alkyl group, an acryloylalkyl group, a methacryloylalkyl group, an acryloyloxyalkyl group, or a methacryloyloxy group. An alkyl group or a mercaptoalkyl group, and the alkyl group in these groups has 2 to 10 carbon atoms,
The other part of R ^{5 to} R ⁷ is a single bond, H, OH, O—, an alkyl group, or an alkoxyl group], and a polymerizable silicon compound residue of
In the formula ^(1), a part of R ^1, R 2, ^{R 3} and ^{R 4} are O-, bonded to Si of the formula ^(2), R ^1, R 2, ^{R 3} and ^{R 4} other At least one of the moieties is O ⁻ , or OH, and at least one of the other moieties of R ¹ , R ² , R ³ and R ⁴ is optionally O— and other silicate structures It may be bonded to the unit Si,
One or two of R ^{5 to} R ⁷ of the polymerizable silicon compound residue of the formula (2) is optionally O-, and is bonded to Si of the silicate structural unit or other polymerizable silicon compound residue. There is
The organic-inorganic hybrid particle | grains whose active silicic acid structural unit shown to Formula (1) is 1-20, and the polymerizable silicon compound residue shown to Formula (2) is 1-200.   2. The particle according to claim 1, wherein the number of silicic acid structural units is 1 to 10, and the polymerizable silicon compound residue is 1 to 100. 3.   The particle | grains of Claim 1 or 2 which have the said polymerizable silicon compound residue 1-6 with respect to the said silicic acid structural unit. In formula (2), R ⁵ is H, CH ₃ , OH, OCH ₃ or OC ₂ H ₅ , R ⁶ is OH, OCH ₃ or OC ₂ H ₅ , and R ⁷ is an acryloylalkyl group. The particle according to any one of claims 1 to 3, which is a methacryloylalkyl group, an acryloyloxyalkyl group, a methacryloyloxyalkyl group, or a mercaptoalkyl group (SH).   The particle | grains in any one of Claims 1-4 whose particle diameter is 1 nm-200 nm.   The particle | grains of any one of Claims 1-4 which have the said polymerizable silicon compound residue 1-3 with respect to the said silicic-acid structural unit, and have a particle diameter of 100 nm-200 nm.   The particle | grains of any one of Claim 1, 2 and 4 which have the said polymerizable silicon compound residue 4-10 with respect to the said silicic-acid structural unit, and have a particle diameter of 1 nm-100 nm.   A polymerizable alkoxysilane compound having a vinyl group, an acryloylalkyl group, a methacryloylalkyl group, an acryloyloxyalkyl group, a methacryloyloxyalkyl group, and / or a mercaptoalkyl group (SH) is added to an aqueous solution of activated silicic acid. A method for producing organic-inorganic hybrid particles, comprising a step of subjecting a compound to a condensation reaction. The aqueous solution of active silicic acid is obtained by treating an aqueous solution of a metal salt of silicic acid with a cation exchange resin to remove metal ions,
The production method according to claim 8, wherein the polymerizable alkoxysilane compound is added to the obtained aqueous solution of active silicic acid in a time shorter than 10 hours after the ion exchange treatment.   10. The polymerizable alkoxysilane compound is added at a molar ratio of the polymerizable alkoxysilane compound to the active silicic acid (active silicic acid: alkoxysilane) at a ratio of 1: 1 to 1:20. the method of.   Within 1 hour after the ion exchange treatment, the polymerizable alkoxysilane compound is used in a molar ratio of the polymerizable alkoxysilane compound to the active silicic acid (active silicic acid: alkoxysilane) of 1: 5 to 1:20. The method according to any one of claims 8 to 10, which is added to the method.   The hydrolyzable alkoxysilane compound is hydrolyzed with an acidic solution having a pH of 2 or less and then added to the aqueous solution of active silicic acid, or the polymerizable alkoxysilane compound is added to an aqueous solution of the active silicic acid having a pH of 2 or less. The method described in 1.   11. The polymerizable alkoxysilane compound according to any one of claims 8 to 10, wherein the polymerizable alkoxysilane compound is added at a molar ratio of the polymerizable alkoxysilane to the active silicic acid (active silicic acid: alkoxysilane) in a ratio of 1: 1 to 1: 4. 2. The method according to item 1.   The method according to claim 13, wherein the polymerizable alkoxysilane compound is added to an aqueous solution of the activated silicic acid having a pH of 3 to 5.   Organic-inorganic hybrid particles obtained by the method according to any one of claims 8 to 14.