JP7587976B2 - Composition, method for producing composition, optical element, and method for producing optical element - Google Patents

Description

The present disclosure relates to a composition, a method for producing a composition, an optical element, and a method for producing an optical element.

As a film having anti-fogging properties, a film formed from a hydrophilic coating agent containing an alkoxysilyl group-containing polymer obtained by polymerizing a monomer component containing a specific betaine monomer and a specific alkoxysilyl group-containing compound is known (for example, Patent Document 1).

Patent No. 6467226

The present disclosure relates to a composition that includes a first compound having a betaine structure and a group represented by formula (1) described below, and a second compound that has a group represented by formula (1) and a hydrophilic group and does not have a betaine structure, and the molecular weight of the second compound is 2000 or less.

1 is a cross-sectional view of a spectacle lens as one embodiment of an optical element.

The composition of this embodiment will be described in detail below.
There is a demand for a composition capable of forming a coating film having excellent self-cleaning properties. The coating film that can be formed using the composition of the present embodiment has the above-mentioned properties.
In this specification, the word "to" is used to mean that the numerical values before and after it are included as the lower limit and upper limit.
In this specification, examples of halogen atoms include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.
As used herein, halogenation includes, for example, fluorination, chlorination, bromination, and iodination.

The components contained in the composition are described in detail below.

<First Compound>
The composition includes a first compound.
The first compound has a betaine structure and a group represented by formula (1) described below.
The betaine structure of the first compound shows strong hydrophilicity, and when a compound having a betaine structure is used to form a coating film, the hydrophilicity of the coating film is improved.It is believed that such a coating film has good self-cleaning properties, and even if dirt adheres to the surface, the dirt can be removed or easily removed by contacting the coating film with water.This is believed to be because the coating film has high hydrophilicity, so even if dirt adheres to the surface, when the coating film is contacted with water, water penetrates between the dirt and the coating film, causing the dirt to float up.
The first compound has a group represented by formula (1). It is believed that the first compound is capable of forming a chemical bond between the first compound and another material or between the first compounds themselves via the group represented by formula (1), thereby making it possible to fix the first compound in the coating film.

The first compound may be a low molecular weight compound or a high molecular weight compound, and is more preferably a high molecular weight compound.
The polymer compound may be a linear polymer with or without side chains, or may be other than that. The polymer compound may have or may not have a block structure, may have or may not have a graft structure, may have or may not have a branch structure or a star structure.
The number average molecular weight of the first compound is preferably at least 1000, and more preferably at least 2000. The number average molecular weight of the first compound is preferably at most 1,000,000, and more preferably at most 500,000.
In the present disclosure, the number average molecular weight and weight average molecular weight are polyethylene glycol equivalent number average molecular weight and weight average molecular weight measured by GPC (gel permeation chromatography).

(Betaine structure)
The first compound includes a betaine structure.
A betaine structure, for example, is a structure in which both a cationic group and an anionic group are present in a structure formed by a covalent bond.
The cationic group and the anionic group may each independently be a monovalent group or a divalent or higher valent linking group.
Examples of the cationic group include ammonium groups (such as groups having "N ⁺ (-*) ₄ "), sulfonium groups (such as groups having "S ⁺ (-*) ₃ "), phosphonium groups (such as groups having "P ⁺ (-*) ₄ "), carbocation groups (such as groups having "C ⁺ (-*) ₃ "), and nitrogen-containing cationic groups other than ammonium groups (such as monovalent or divalent pyridinium groups). In the above, * represents a bonding position. The ammonium group may have a ring structure, and examples of such ammonium groups include monovalent or divalent piperidinium groups and monovalent or divalent pyrrolidinium groups. The pyridinium groups, piperidinium groups, and pyrrolidinium groups may have a substituent.
Examples of the anion group include a sulfonate anion group (-SO ₃ ^- ), a carboxylate anion group (-COO ^- ), a phosphonate anion group (-PO ₃ H ^- , -PO ₃ ^2-, etc.), and a phosphate anion group (-OPO ₃ ^- -, etc.).
In the betaine structure, the cationic atom (N ⁺ , S ⁺ , P ⁺ , C ^{+ ,} etc.) in the cationic group does not have to be directly bonded to the anionic group.
In addition, the betaine structure is preferably a sulfobetaine structure, a phosphobetaine structure, or a carbobetaine structure.
A sulfobetaine structure is a betaine structure having a sulfonate anion group, a phosphobetaine structure is a betaine structure having a phosphonate anion group or a phosphate ester anion group, and a carbobetaine structure is a betaine structure having a carboxylate anion group.

The number of betaine structures contained in the first compound is 1 or more, and preferably 1 to 1,000.
When the first compound has a plurality of betaine structures, the first compound may have one type of betaine structure alone or two or more types of betaine structures.
When the first compound has a plurality of betaine structures, the first compound preferably has one or more structures selected from the group consisting of a sulfobetaine structure, a phosphobetaine structure, and a carbobetaine structure.

The betaine structure may be a structure represented by "-anionic group-linking group-cationic group" or "-cationic group-linking group-anionic group", and may be a structure represented by formula (B1) or a structure represented by formula (B2).

-L ^A -C ^B1 -L ^B -A ^B1 (B1)
-L ^A -A ^B2 -L ^B -C ^B2 (B2)

In formula (B1), L 1 ^A represents a single bond or a divalent linking group.
Examples of the divalent linking group include -CO-, -O-, -SO-, -SO ₂ -, -NR ^A -, alkylene groups (e.g., having 1 to 6 carbon atoms, which may be linear or branched), alkenylene groups (e.g., having 2 to 6 carbon atoms, which may be linear or branched), alkynylene groups (e.g., having 2 to 6 carbon atoms, which may be linear or branched), arylene groups (e.g., having 6 to 15 carbon atoms, which may be monocyclic or polycyclic), heteroarylene groups (e.g., having 5 to 15 ring atoms, which may be monocyclic or polycyclic), alicyclic groups (e.g., having 3 to 15 carbon atoms, which may be monocyclic or polycyclic), non-aromatic heterocyclic groups (e.g., having 3 to 15 ring atoms, which may be monocyclic or polycyclic), and groups combining a plurality of these.
R ^{3 A} represents a hydrogen atom or a substituent, and is preferably a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.
The alkylene group, the alkenylene group, the alkynylene group, the arylene group, the heteroarylene group, the alicyclic group, and the non-aromatic heterocyclic group may have a substituent.

In formula (B1), C ^B1 represents a divalent cationic group.
Examples of the cationic group include -N ⁺ R ^N ₂ -, a divalent pyridinium group which may have a substituent, a divalent piperidinium group which may have a substituent, and a divalent pyrrolidinium group which may have a substituent.
Each of the two R ^N in -N ⁺ R ^N ₂ - independently represents a hydrogen atom or a substituent, and is preferably a hydrogen atom or an alkyl group. The alkyl group may be linear or branched, and preferably has 1 to 5 carbon atoms. The alkyl group may have a substituent, and examples of the substituent that the alkyl group may have include a hydroxyl group.
The pyridinium group is preferably such that a nitrogen atom, which is a ring atom of the pyridinium group, is directly bonded to L ^{1 A} or L 1 ^B.
It is also preferable that the nitrogen atom, which is a ring member atom, of the piperidinium group and the pyrrolidinium group is directly bonded to L 1 ^A and/or L 1 ^B.

In formula (B1), L 1 ^B represents a single bond or a divalent linking group.
Examples of the divalent linking group include -CO-, -O-, -SO-, -SO ₂ -, -NR ^A -, alkylene groups (e.g., having 1 to 6 carbon atoms, which may be linear or branched), alkenylene groups (e.g., having 2 to 6 carbon atoms, which may be linear or branched), alkynylene groups (e.g., having 2 to 6 carbon atoms, which may be linear or branched), arylene groups (e.g., having 6 to 15 carbon atoms, which may be monocyclic or polycyclic), heteroarylene groups (e.g., having 5 to 15 ring atoms, which may be monocyclic or polycyclic), alicyclic groups (e.g., having 3 to 15 carbon atoms, which may be monocyclic or polycyclic), non-aromatic heterocyclic groups (e.g., having 3 to 15 ring atoms, which may be monocyclic or polycyclic), and groups combining a plurality of these.
R ^{3 A} represents a hydrogen atom or a substituent, and is preferably a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.
The alkylene group, the alkenylene group, the alkynylene group, the arylene group, the heteroarylene group, the alicyclic group, and the non-aromatic heterocyclic group may have a substituent.
When L 3 ^B is a single bond, it is preferable that the cationic atom (N ^{3 +} or the like) in the cationic group represented by C ^B1 does not directly bond to the monovalent anionic group represented by A ^B1 described below.

In formula (B1), A ^B1 represents a monovalent anion group, preferably —SO ₃ ^— or —COO ^— .

In formula (B2), L 1 ^A represents a single bond or a divalent linking group.
The form of the divalent linking group L 1 ^A is the same as the form of the divalent linking group L 1 ^A in formula (B1).

In formula (B2), A ^B2 represents a divalent anionic group.
The anionic group is preferably --OPO ₃ ^-- .

In formula (B2), L 1 ^B represents a single bond or a divalent linking group.
The form of L 3 ^B as a divalent linking group in formula (B2) is the same as the form of L 3 ^B as a divalent linking group in formula (B1).
When L 3 ^B is a single bond, it is preferable that the anionic group represented by A 3 ^B2 is not directly bonded to a cationic atom (N ^{3 +} or the like) in the monovalent cationic group represented by C 3 ^B2 described below.

In formula (B2), C ^B2 represents a monovalent cationic group.
Examples of the cationic group include -N ⁺ R ^N ₃ , an optionally substituted monovalent pyridinium group, an optionally substituted monovalent piperidinium group, and an optionally substituted monovalent pyrrolidinium group.
Each of the three R ^N in -N ⁺ R ^N ₃ independently represents a hydrogen atom or a substituent, and is preferably a hydrogen atom or an alkyl group. The alkyl group may be linear or branched, and preferably has 1 to 5 carbon atoms. The alkyl group may have a substituent, and examples of the substituent that the alkyl group may have include a hydroxyl group.
The pyridinium group is preferably such that the nitrogen atom, which is a ring atom of the pyridinium group, is directly bonded to L 2 ^B.
It is also preferable that the nitrogen atom, which is a ring member atom, of the piperidinium group and the pyrrolidinium group is directly bonded to L 1 ^A and/or L 1 ^B.

There is no limitation on how the betaine structure is present in the first compound. For example, the betaine structure may be present at the terminal of the main chain of the first compound, which is a polymer compound, or may be present in a side chain of the first compound, which is a polymer compound.
In particular, the first compound may have a repeating unit represented by the following formula (X): That is, the first compound may have a betaine structure by having a repeating unit represented by formula (X).

In formula (X), R ^X1 to R ^X3 each independently represent a hydrogen atom or a substituent. The substituent is preferably an alkyl group (such as a methyl group) or a group having a group represented by formula (1).
The group having a group represented by the above formula (1) may be the group represented by the formula (1) itself, or may be a group having a group represented by the formula (1) as a part thereof. The group represented by the formula (1) will be described later.

In formula (X), m represents an integer of 1 or more, preferably 1 to 5, more preferably 1 or 2, and even more preferably 1.
In formula (X), ^BX represents a betaine structure. The betaine structure may be the structure represented by formula (B1) or the structure represented by formula (B2).
When m is 2 or more, m B 1 ^X 's are independent and may be the same or different.

In formula (X), L ^X1 represents a single bond, —COO—, or —CONH—. In —COO— and —CONH—, it is preferable that the carbonyl carbon is present on the main chain side.

In formula (X), L ^X2 represents a single bond or a linking group having a valence of (m+1).
However, when L ^X2 is a single bond, m is 1.
Examples of the linking group include -CO-, -O-, -SO-, -SO ₂ -, -NR ^A - (R ^A is a hydrogen atom or a substituent), an alkylene group (e.g., having 1 to 6 carbon atoms, which may be linear or branched), an alkenylene group (e.g., having 2 to 6 carbon atoms, which may be linear or branched), an alkynylene group (e.g., having 2 to 6 carbon atoms, which may be linear or branched), a trivalent group represented by "-N<", a trivalent group represented by "-CR ^Y <" (R ^Y is a hydrogen atom or a substituent), a tetravalent group represented by ">C<", an aromatic hydrocarbon ring group (e.g., having 6 to 15 carbon atoms, which may be monocyclic or polycyclic), an aromatic heterocyclic group (e.g., having 5 to 15 ring atoms, which may be monocyclic or polycyclic), an alicyclic group (e.g., having 3 to 15 ring atoms, which may be monocyclic or polycyclic), a non-aromatic heterocyclic group (e.g., having 3 to 15 ring atoms, which may be monocyclic or polycyclic), and a group combining a plurality of these.
The alkylene group, the alkenylene group, the alkynylene group, the aromatic hydrocarbon ring group, the aromatic heterocyclic group, the alicyclic group, and the non-aromatic heterocyclic group may have a substituent.

The repeating unit represented by formula (X) may be used alone or in combination of two or more kinds.
In the first compound, the content of the repeating unit represented by formula (X) is preferably more than 0 mass% and not more than 100 mass%, more preferably 30 to 100 mass%, still more preferably 60 to 100 mass%, and particularly preferably 90 to 100 mass%, based on all repeating units of the first compound.

(Group represented by formula (1))
The first compound has a group represented by formula (1).
-Si(R ¹ ) _n (R ² ) _3-n (1)

In formula (1), n represents an integer of 1 to 3.
In other words, the group represented by formula (1) contains a total of three ^R1s and ^R2s .

In formula (1), R ¹ represents a hydroxyl group or a hydrolyzable group.
Examples of the hydrolyzable group include an alkoxy group (preferably having 1 to 10 carbon atoms), an acetoxy group, and a halogen atom such as a chlorine atom, with an alkoxy group being more preferred.
When two or more R ^1s are present, the two or more R ^1s are independent and may be the same or different.

In formula (1), R ² represents a group which is neither a hydroxyl group nor a hydrolyzable group.
Examples of ^R2 include a hydrogen atom and a non-hydrolyzable group, and more specifically, a hydrogen atom and an alkyl group (which may be linear or branched, and preferably has 1 to 6 carbon atoms).

There is no limitation on the form in which the first compound has a group represented by formula (1), and for example, when the first compound is a polymer compound, the group represented by formula (1) may or may not be present at an end (one end or both ends, etc.) of its chain structure. Also, when the first compound is a polymer compound, the group represented by formula (1) may be present in its side chain.
The first compound has one or more groups represented by formula (1) (for example, 1 to 1000 groups).
In particular, it is more preferable that the first compound has a group represented by formula (1) only at an end (preferably one end) of the first compound, which is a polymer compound.

There is no limitation on the method for introducing the group represented by formula (1) into the first compound, and examples of the method include a method in which a polymerization initiator having a group represented by formula (1) and/or a chain transfer agent having a group represented by formula (1) is used when synthesizing the first compound, which is a polymer compound, by polymerization (radical polymerization, etc.).
An example of the polymerization initiator having a group represented by formula (1) is a compound represented by formula (1-A).
An example of the chain transfer agent having a group represented by formula (1) is a compound represented by formula (1-B).

R ^S -L ^S -N=N-L ^S -R ^S (1-A)
R ^S -L ^S -SH (1-B)

In formula (1-A) and formula (1-B), R 1 ^S is a group represented by formula (1).
In formula (1-A), a plurality of R 2 ^S's are independent and may be the same or different.
In formula (1-A) and formula (1-B), L 1 ^S represents a single bond or a divalent linking group.
Examples of the divalent linking group include -CO-, -O-, -SO-, -SO ₂ -, -NR ^A -, alkylene groups (e.g., having 1 to 6 carbon atoms, which may be linear or branched), alkenylene groups (e.g., having 2 to 6 carbon atoms, which may be linear or branched), alkynylene groups (e.g., having 2 to 6 carbon atoms, which may be linear or branched), arylene groups (e.g., having 6 to 15 carbon atoms, which may be monocyclic or polycyclic), heteroarylene groups (e.g., having 5 to 15 ring atoms, which may be monocyclic or polycyclic), alicyclic groups (e.g., having 3 to 15 carbon atoms, which may be monocyclic or polycyclic), non-aromatic heterocyclic groups (e.g., having 3 to 15 ring atoms, which may be monocyclic or polycyclic), and groups combining a plurality of these.
R ^{3 A} represents a hydrogen atom or a substituent, and is preferably a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.
The alkylene group, the alkenylene group, the alkynylene group, the arylene group, the heteroarylene group, the alicyclic group, and the non-aromatic heterocyclic group may have a substituent.
In formula (1-A), a plurality of L 2 ^S's are independent and may be the same or different.

(Other parts)
The first compound (particularly the first compound which is a polymer compound) may have a structural portion other than those described above.
For example, the first compound, which is a polymer compound, may have a repeating unit other than the repeating unit represented by formula (X), or may have a repeating unit that does not have a betaine structure.
For example, the first compound may have a repeating unit having a structure formed by polymerization of one or more monomers selected from the group of monomers shown below.
Monomer group: styrene, α-hydroxystyrene, p-hydroxystyrene, methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, neopentyl (meth)acrylate, cyclohexyl (meth)acrylate, benzyl (meth)acrylate, octyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, cetyl (meth)acrylate, ethyl carbitol (meth)acrylate, hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, Methoxyethyl acrylate, methoxybutyl (meth)acrylate, N-methyl (meth)acrylamide, N-ethyl (meth)acrylamide, N-propyl (meth)acrylamide, N-isopropyl (meth)acrylamide, N-butoxymethyl (meth)acrylamide, N-tert-butyl (meth)acrylamide, N-octyl (meth)acrylamide, N,N-dimethyl (meth)acrylamide, N,N-diethyl (meth)acrylamide, (meth)acryloylmorpholine, diacetone (meth)acrylamide, methyl itaconate, ethyl itaconate, vinyl acetate, vinyl propionate, N-vinylpyrrolidone, N-vinylcaprolactam

There is no limitation on the method for producing the first compound, and for example, the first compound may be obtained by radical polymerization of a monomer corresponding to the repeating unit represented by formula (X) in the presence of a polymerization initiator having a group represented by formula (1) and/or a chain transfer agent having a group represented by formula (1). In this case, if desired, a polymerizable monomer not having a betaine structure (e.g., one or more monomers selected from the above-mentioned monomer group) may be added to the reaction system to introduce a repeating unit not having a betaine structure into the first compound.

The first compound may be used alone or in combination of two or more.
The content of the first compound in the composition is preferably from 1 to 90 mass %, more preferably from 5 to 75 mass %, and even more preferably from 10 to 70 mass %, based on the total solid content of the composition.
The solid content of the composition is the heating residue measured in accordance with JIS K 5601-1-2. The drying conditions for the measurement are a heating time of 60 minutes, a heating temperature of 105° C., and a sample weight of 1±0.1 g.

<Second Compound>
The composition includes a second compound.
The second compound has a group represented by formula (1) and a hydrophilic group, and does not have a betaine structure.
The molecular weight of the second compound is 2000 or less, preferably less than 1000, and more preferably 500 or less. The molecular weight of the second compound is preferably 100 or more, and more preferably 120 or more.
It is believed that the presence of the second compound together with the first compound suppresses aggregation of the first compound in the coating film formed using the composition, and also improves the molecular mobility of the first compound in the coating film, thereby improving the self-cleaning properties.
The "first compound in the coating film" may be a component derived from the first compound in the composition, and may be a compound that has undergone a chemical change from the state in which the first compound was present in the composition.

The group represented by formula (1) contained in the second compound is as described above. The number of groups represented by formula (1) contained in the second compound is 1 or more (for example, 1 to 10), and more preferably 1.
When the second compound has a plurality of groups represented by formula (1), the plurality of groups represented by formula (1) are independent of each other and may be the same or different.
The group represented by formula (1) in the second compound may be the same as or different from the group represented by formula (1) in the first compound.

Examples of the hydrophilic group contained in the second compound include an acid group, a hydroxyl group, and an amino group (such as a primary amino group), with an acid group being more preferred.
Examples of the acid group include a carboxylic acid group (-COOH), a sulfonic acid group (-SO ₃ H), a phosphoric acid group (-OP(=O)(OH) ₂ ), a phosphonic acid group (-P(=O)(OH) ₂ ), a sulfate group (-OSO ₃ H), a phosphoric acid ester-containing group (-OP(=O)(OR ^S )(OR ^T )), a phosphonic acid ester-containing group (-OP(=O)(R ^S )(OR ^T ), -P(=O)(OR ^S )(OR ^T )), and salts formed by these groups when possible (for example, alkali metal salts such as sodium salts, alkaline earth metal salts such as calcium salts, and ammonium salts).
The hydrophilic groups may be ionized in the composition.
In -OP(=O)(OR ^S )(OR ^T ), -OP(=O)(R ^S )(OR ^T ), and -P(=O)(OR ^S )(OR ^T ), R ^S and R ^T each independently represent a hydrogen atom or a substituent (such as an alkyl group having 1 to 6 carbon atoms).
The second compound has one or more hydrophilic groups (eg, 1 to 10), and one is more preferable.
The groups contained in the group represented by formula (1) are not included in the number of hydrophilic groups.

The second compound may be a compound represented by formula (2).
XL-Si(R ¹ ) _n (R ² ) _3-n (2)

In formula (2), n represents an integer of 1 to 3.
^R1 represents a hydroxyl group or a hydrolyzable group.
^R2 represents a group which is neither a hydroxyl group nor a hydrolyzable group.
The partial structure represented by "-Si(R ¹ ) _n (R ² ) _3-n " in formula (2) is the same as the group represented by formula (1) above.

In formula (2), X represents a hydrophilic group.
The hydrophilic group is the same as the hydrophilic group contained in the second compound.

In formula (2), L represents a divalent linking group.
Examples of the divalent linking group include -CO-, -O-, -SO-, -SO ₂ -, -NR ^A -, alkylene groups (e.g., having 1 to 6 carbon atoms, which may be linear or branched), alkenylene groups (e.g., having 2 to 6 carbon atoms, which may be linear or branched), alkynylene groups (e.g., having 2 to 6 carbon atoms, which may be linear or branched), arylene groups (e.g., having 6 to 15 carbon atoms, which may be monocyclic or polycyclic), heteroarylene groups (e.g., having 5 to 15 ring atoms, which may be monocyclic or polycyclic), alicyclic groups (e.g., having 3 to 15 carbon atoms, which may be monocyclic or polycyclic), non-aromatic heterocyclic groups (e.g., having 3 to 15 ring atoms, which may be monocyclic or polycyclic), and groups combining a plurality of these.
R ^{3 A} represents a hydrogen atom or a substituent, and is preferably a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.
The alkylene group, the alkenylene group, the alkynylene group, the arylene group, the heteroarylene group, the alicyclic group, and the non-aromatic heterocyclic group may have a substituent.

The second compound may be used alone or in combination of two or more.
The content of the second compound in the composition is preferably from 1 to 90 mass %, more preferably from 5 to 75 mass %, and even more preferably from 20 to 50 mass %, based on the total solid content of the composition.
In the composition, the mass ratio of the content of the second compound to the content of the first compound (content of the second compound/content of the first compound) is preferably 1/99 to 99/1, and more preferably 10/90 to 90/10.

<Salt>
The composition may contain a salt as an ingredient other than the above-mentioned ingredients.
It is believed that the presence of a salt in the composition can inhibit aggregation of the first compound in the composition.
The salt may be an inorganic salt or an organic salt, with an inorganic salt being more preferred.
Examples of the salt include NaCl, KCl, LiCl, MgCl ₂ , BaCl ₂ , NaF, KF, LiF, MgF ₂ , BaF ₂ , NaBr, KBr, LiBr, MgBr ₂ , BaBr ₂ , NaI, KI, LiI, MgI ₂ , BaI ₂ , _Na2SO4 , _{K2SO4 , Li2SO4 , MgSO4 , Na2CO3 , NaHCO3 , K2CO3 , KHCO3 , Li2CO3} , _LiHCO3 , _MgCO3 , _NaNO3 , _KNO3 , _LiNO3 , _MgNO3 , _BaNO3 , sodium oxalate, sodium acetate, sodium citrate, and sodium tartrate.
The salts may be used alone or in combination of two or more.
When the composition contains a salt, the content of the salt is preferably from 0.1 to 90 mass %, more preferably from 0.5 to 80 mass %, and even more preferably from 1 to 70 mass %, based on the total solid content of the composition.
When the composition contains a salt, the content of the salt is preferably 1% by mass or more, more preferably 3% by mass or more, based on the total mass of the first compound, and is preferably 70% by mass or less, more preferably 60% by mass or less.

<Solvent>
The composition may include a solvent.
The solvent may be, for example, an inorganic solvent such as water, or an organic solvent.
The type of organic solvent is not particularly limited, and examples thereof include alcohol-based solvents such as methanol, ethanol, isopropyl alcohol, ethylene glycol, and propylene glycol; ketone-based solvents such as acetone and methyl ethyl ketone; ether-based solvents such as diethyl ether and tetrahydrofuran; ester-based solvents such as methyl acetate, ethyl acetate, and butyl acetate; hydrocarbon-based solvents such as benzene, toluene, and xylene; halogenated hydrocarbon-based solvents; amide-based solvents; sulfone-based solvents; and sulfoxide-based solvents.
The solvent may be used alone or in combination of two or more kinds.
The solvent is preferably capable of dissolving the first compound, the second compound, and the inorganic salt added as desired. When the composition is a mixed solvent of two or more solvents, the mixed solvent as a whole is required to be capable of dissolving the first compound, the second compound, and the inorganic salt added as desired.
The solvent more preferably contains water. When the solvent contains water, the content of water is preferably 10 to 100 mass%, more preferably 60 to 100 mass%, and even more preferably 90 to 100 mass%, based on the total mass of the solvent.
When the composition contains a solvent, the content of the solvent is preferably from 10 to 99.9 mass %, more preferably from 60 to 99.5 mass %, and even more preferably from 80 to 99 mass %, based on the total mass of the composition.

<Other ingredients>
The composition may contain other components in addition to those described above, and may contain various additives such as, for example, a catalyst, a surfactant, an antiaging agent, a coating modifier, a light stabilizer, an antioxidant, a color inhibitor, a dye, a filler, and an internal mold release agent.

<Production method of composition>
The method for producing the composition is not particularly limited. For example, the above-mentioned components may be mixed all at once, or each component may be mixed in portions in stages.
In particular, the method for producing the composition preferably includes blending the second compound with a solution containing the first compound.
There is no limitation on the method of mixing the second compound with the solution containing the first compound, as long as these components are mixed. For example, the mixing may be performed by adding the second compound or a solution containing the second compound to a solution containing the first compound, or the mixing may be performed by adding the solution containing the first compound to the second compound or a solution containing the second compound.
In order to adjust the content of the solvent in the composition, a necessary amount of the solvent may be added to the solution containing the first compound and/or the solution containing the second compound. Alternatively, the content of the solvent in the final composition may be adjusted by adding a further solvent to the solution obtained by adding the second compound to the solution containing the first compound.
In addition, when the composition contains a salt, the salt may be blended into a solution containing the first compound, or into a solution containing the second compound, or the salt may be further added to a solution obtained by blending the second compound into a solution containing the first compound.

<Optical elements>
The composition can be used in the manufacture of optical elements.
An optical element having a substrate and a coating film formed from the above-mentioned composition disposed on the substrate has a coating film with excellent self-cleaning properties, and can be usefully used as an optical element with excellent self-cleaning properties.
An example of an optical element is a lens such as a spectacle lens.

(Coating film)
The coating film is a film formed using the above-mentioned composition. The thickness of the coating film is preferably 1 to 1000 μm.

(Substrate)
The substrate may be an optical substrate, preferably a lens substrate (a substrate used for manufacturing lenses), more preferably a spectacle lens substrate, and even more preferably a plastic spectacle lens substrate (a spectacle lens substrate made of plastic).
Examples of materials constituting the substrate include plastics (resins) and glass. The type of plastic (so-called resin) is not particularly limited, but examples include (meth)acrylic acid ester resins, thiourethane resins, allyl resins, episulfide resins, polycarbonates, urethane resins, polyesters, polystyrene, polyethersulfones, poly-4-methylpentene-1, and diethylene glycol bisallyl carbonate resins (CR-39). The plastics may contain additives such as bluing agents, light stabilizers, and antioxidants.

The thickness of the substrate is not particularly limited, but from the viewpoint of ease of handling, it is often about 1 to 30 mm.
The refractive index of the plastic constituent material is not particularly limited, but is often 1.50 or more, preferably 1.60 to 1.80, and more preferably 1.60 to 1.74.

The substrate may have one or more functional layers on the surface of the above-mentioned components.
Examples of the functional layer include a primer layer, a hard coat layer, and an anti-reflection layer.

The primer layer is a layer that improves adhesion between layers (including coating films).
The material constituting the primer layer is not particularly limited, and known materials can be used, for example, resins are mainly used. The type of resin used is not particularly limited, and examples thereof include urethane resins, epoxy resins, phenolic resins, polyimide resins, polyester resins, bismaleimide resins, and polyolefin resins.

The method for forming the primer layer is not particularly limited, and any known method can be used. For example, a method can be used in which a primer layer-forming composition containing a predetermined resin is applied onto a constituent material, and a curing treatment is performed as necessary to form a primer layer.
The thickness of the primer layer is not particularly limited and is, for example, 0.3 to 2 μm.

The hard coat layer is a layer that imparts scratch resistance to the plastic lens. In this specification, the hard coat layer is defined as a layer that exhibits a pencil hardness of "H" or more according to the test method specified in JIS K5600.
As the hard coat layer, a known hard coat layer can be used, and examples thereof include an organic hard coat layer, an inorganic hard coat layer, and an organic-inorganic hybrid hard coat layer.

The antireflection layer is a layer having a function of preventing reflection of incident light. In this specification, the antireflection layer is defined as a layer that exhibits a reflection characteristic in which the reflectance is reduced to about 5% or less in the visible light region of 380 to 780 nm.
The structure of the antireflection layer is not particularly limited, and may be a single-layer structure or a multi-layer structure.
In the case of a multi-layer structure, for example, a structure in which low refractive index layers and high refractive index layers are alternately laminated can be given. Note that examples of materials constituting the high refractive index layers include oxides of titanium, zircon, aluminum, tantalum, and lanthanum. Also, examples of materials constituting the low refractive index layers include silica.

FIG. 1 is a cross-sectional view of a spectacle lens as one embodiment of an optical element.
The spectacle lens 10 shown in Figure 1 includes a plastic spectacle lens substrate 12 and a coating 14 disposed on both sides of the plastic spectacle lens substrate 12. The coating 14 is a layer made (formed) using the composition described above.
In FIG. 1, the coating film 14 is disposed on both sides of the plastic eyeglass lens substrate 12, but the coating film 14 may be disposed on only one side of the plastic eyeglass lens substrate 12.

<Method of Manufacturing Optical Element>
There is no limitation on the method for producing the optical element, and for example, there can be mentioned a method including applying the above-mentioned composition onto a substrate to form a coating film.
The coating film is preferably formed by curing a composition layer made of a composition applied onto a substrate.

The method for applying the composition onto the substrate is not particularly limited, and includes known methods (for example, dipping coating, spin coating, spray coating, inkjet coating, and flow coating).
For example, when a dip coating method is used, a substrate is immersed in the composition, and then the substrate is pulled out and dried, thereby forming a composition layer of a predetermined thickness on the substrate.
There are no particular limitations on the thickness of the composition layer formed on the substrate, and the thickness is appropriately selected so as to achieve a desired coating thickness.
The substrate to which the composition is applied may have one or more functional layers (such as a hard coat layer, a primer layer, and/or an anti-reflection layer) previously formed on the surface of the above-mentioned constituent materials.
Before applying the composition onto a substrate, the substrate may be subjected to cleaning and/or surface treatment.

There is no limitation on the method for curing the composition layer. For example, the composition layer may be subjected to a drying treatment and then a curing treatment.
In the drying treatment, the treatment temperature is preferably 30 to 80° C., and the treatment time is preferably 5 to 60 minutes.
In the curing treatment, the treatment temperature is preferably 30 to 80° C., and the treatment time is preferably 20 to 200 minutes. The curing treatment is preferably carried out in a high humidity environment, and is also preferably carried out in an environment of 40 to 95% RH.
The drying and curing processes may be carried out simultaneously as a single process sequence.
After the composition layer is cured, the surface of the formed coating film may be washed. This makes it possible to remove any uncured composition that may remain on the surface from the surface of the coating film. A solvent such as water can be used for washing.

The composition will be described in more detail below with reference to examples and comparative examples, but the composition is not limited in any way by these examples.

The raw materials used in the preparation of the compositions of the Examples and Comparative Examples will be described below.
First compound-containing solution: LAMBIC 771W (manufactured by Osaka Organic Chemical Industry Ltd., an aqueous solution containing a polymer of a monomer having a sulfobetaine structure and having a hydroxysilyl group (corresponding to the group represented by formula (1)), solid content 10% by mass)
Second compound-containing solution: 3-(trihydroxysilyl)propylmethylphosphonate, monosodium salt aqueous solution (Sigma-Aldrich, solid content 50% by mass)

Example 1
The first compound-containing solution was mixed with the second compound-containing solution and water (deionized water) in predetermined amounts to obtain composition 1.
Composition 1 contains 1.97 mass % of solids derived from the first compound-containing liquid relative to the total mass of the composition, and contains 0.66 mass % of solids derived from the second compound-containing liquid relative to the total mass of the composition.

The obtained composition was used to immerse a lens with an antireflection layer (Nikon-Essilor, product name ECC, from which the topcoat layer had been removed (a lens that had no topcoat layer attached from the beginning) that had been cleaned with an ozone cleaner (I-Graphics, OC2506, treatment time 3 minutes) and dip-coated at a pull-up speed of 4 mm/sec.
The lens was then dried by heating in a thermostatic chamber at 50° C. for 20 minutes, and further dried by heating in a thermostatic chamber at 50° C. and 80% RH for 60 minutes. Finally, the lens was washed under running tap water until the slime on the surface (coating components that did not react with the substrate) was reduced, to obtain the lens (optical element) of Example 1.

Example 2
The solution containing the first compound, the solution containing the second compound, water (deionized water), and sodium chloride to be further added were mixed in predetermined amounts to obtain a composition 2.
Composition 2 contains 1.02 mass% of solids derived from the first compound-containing liquid based on the total mass of the composition, 1.04 mass% of solids derived from the second compound-containing liquid based on the total mass of the composition, and further contains 0.15 mass% of added sodium chloride based on the total mass of the composition.
A lens of Example 2 was obtained in the same manner except that Composition 2 was used in place of Composition 1.

<Comparative Example 1>
A predetermined amount of water (deionized water) was mixed with the first compound-containing solution to obtain a composition C1.
Composition C1 contains 2.00 mass % of solids derived from the first compound-containing liquid relative to the total mass of the composition.
A lens of Comparative Example 1 was obtained in the same manner except that Composition C1 was used in place of Composition 1.

<Comparative Example 2>
The second compound-containing solution and water (deionized water) were mixed in predetermined amounts to obtain a composition C2.
Composition C2 contains 2.00 mass % of solids derived from the second compound-containing liquid relative to the total mass of the composition.
A lens of Comparative Example 2 was obtained in the same manner except that Composition C2 was used instead of Composition 1.

<Evaluation>
The lenses of the examples and comparative examples were evaluated by the methods described below.

(Unevenness in film thickness)
The unevenness in the thickness of the coating film (coating film formed using the composition) present on the surface of the lens was evaluated visually utilizing differences in interference colors.
If no unevenness in the film thickness was observed, it was rated A, and if unevenness was observed, it was rated B.

(Anti-fogging properties)
The lens was exposed to warm water at 70° C. for 3 seconds, and then the state of the coating film present on the surface of the lens was observed to evaluate the anti-fogging properties of the coating film.
The coating film was rated as A when no water film was formed on the coating film and the coating film did not become cloudy, and the coating film was rated as B when the coating film became cloudy.

(Self-cleaning properties)
The coating film present on the surface of the lens was painted with Zebra Hi-Mackie, Inc. The lens was then placed in tap water and the time it took for the paint to come off was evaluated.
Those in which the paint rose within 30 seconds were rated A, and those in which the paint did not rise within 30 seconds were rated B.

The results of the evaluation are shown in the table below.
In the table, the column "First compound-containing liquid: second compound-containing liquid" indicates the mass ratio of the solid content derived from the first compound-containing liquid to the solid content derived from the second compound-containing liquid in the composition used in each example or comparative example.

As shown in Table 1, it was confirmed that by using a composition containing the specified components, a lens with excellent self-cleaning properties can be obtained.
Furthermore, the lens had reduced unevenness in film thickness and had good anti-fogging properties.
It is believed that the coexistence of the first compound and the second compound reduces aggregation of the first compound, thereby reducing unevenness in the film thickness (see comparison between Examples 1 and 2 and Comparative Example 1).
In addition, it is believed that the coexistence of the first compound and the second compound improves the molecular mobility of the first compound, thereby improving the self-cleaning properties (see comparison between Examples 1 and 2 and Comparative Example 1).

10 eyeglass lens 12 plastic eyeglass lens substrate 14 coating film

Claims (8)

A first compound having a betaine structure and a group represented by formula (1);
a second compound having a group represented by formula (1) and a hydrophilic group and not having a betaine structure,
The molecular weight of the second compound is 2000 or less,
The composition , wherein the second compound is a compound represented by formula (2) .
-Si(R ¹ ) _n (R ² ) _3-n (1)
In formula (1), n represents an integer of 1 to 3.
^R1 represents a hydroxyl group or a hydrolyzable group.
^R2 represents a group which is neither a hydroxyl group nor a hydrolyzable group.
XL-Si(R ¹ ) _n (R ² ) _3-n (2)
In formula (2), n represents an integer of 1 to 3.
R1 represents a hydroxyl group or a hydrolyzable group ^.
R2 represents a group which is neither a hydroxyl group nor a hydrolyzable group ^.
X represents a hydrophilic group.
L represents an alkylene group having 1 to 6 carbon atoms, an alkenylene group having 2 to 6 carbon atoms, or an alkynylene group having 2 to 6 carbon atoms. The composition according to claim 1, wherein the betaine structure is a sulfobetaine structure, a phosphobetaine structure, or a carbobetaine structure. The composition of claim 1 or 2, wherein the molecular weight of the second compound is less than 1000. The composition according to any one of claims 1 to 3, wherein the hydrophilic group is an acid group. A method for producing a composition comprising mixing the second compound with a solution containing the first compound, thereby producing the composition according to any one of claims 1 to 4. A substrate;
A coating film formed from the composition according to any one of claims 1 to 4, disposed on the substrate. The optical element according to claim 6 , wherein the substrate is a lens substrate. A method for producing an optical element, comprising applying the composition according to any one of claims 1 to 4 onto a substrate to form a coating film.