Member for suppressing formation of ice nucleus, suppressing formation of frost, and suppressing accretion of snow and ice

Abstract

Provided is a member that is for suppressing formation of ice nucleus, suppressing formation of frost, and suppressing accretion of snow and ice, and that has a coating film obtained through application of a coating composition containing a solvent and a polymer. The polymer contains: a graft polymer compound (A) that includes a structural unit represented by general formula (1) and that has a crosslinkable functional group (a); and a crosslinkable polymer compound (B) that has two or more reactive functional groups (b) that undergo a cross-linking reaction with the crosslinkable functional group (a). The content proportion of the crosslinkable polymer compound (B) in a total of 100 mass% of the graft polymer compound (A) and the crosslinkable polymer compound (B) is not less than 0.1 mass% but less than 50 mass%. The ice accretion stress of the member at -18°C is 150 kPa or less.

Description

Components for suppressing ice nucleation, frost formation, or snow and ice accumulation

[0001] The present invention relates to a member for suppressing ice nucleation, frost formation, or snow and ice accumulation.

[0002] In heat exchangers used in air conditioners and refrigerators, rapid cooling of air can cause water droplets to adhere to the surface of the cooling element in the heat exchanger, or frost to form, reducing the heat exchange efficiency. In particular, frost forms through the formation of ice on the surface of the cooling element or the formation and growth of ice nuclei. As a method for suppressing frost formation, a method of forming a resin film on the surface of the element is known, as described in Patent Document 1.

[0003] Japanese Patent Application Laid-Open No. 2019-158247

[0004] The present invention has been made in view of the above circumstances, and has as its object to provide a member that can effectively suppress ice nucleation, frost formation, and snow and ice accumulation.

[0005] That is, according to the present invention, there is provided the following member for suppressing ice nucleation, frost formation, or snow and ice accumulation: [1] A member for suppressing ice nucleation, frost formation, or snow and ice accumulation, having a coating film obtained by applying a coating composition containing a solvent and a polymer, wherein the polymer contains a structural unit represented by the following general formula (1), and comprises a graft polymer compound (A) having a crosslinkable functional group (a), and a crosslinkable polymer compound (B) having two or more reactive functional groups (b) that undergo a crosslinking reaction with the crosslinkable functional group (a), wherein the content of the crosslinkable polymer compound (B) is 0.1% by mass or more and less than 50% by mass out of a total of 100% by mass of the graft polymer compound (A) and the crosslinkable polymer compound (B), and the member has an icing stress at −18° C. of 150 kPa or less. (In the general formula (1), R １ represents a hydrogen atom or a methyl group, X represents O or NH, and R ２ represents any organic group, and R ３ and R ４ each independently represents a hydrogen atom, an alkyl group, an aryl group, or an acyl group, and R ３ and R ４is a tertiary or quaternary carbon atom, n represents any number of repeating units, and Polymer represents a graft chain containing a structural unit derived from at least one graft monomer selected from the group consisting of (meth)acrylic acid monomers, (meth)acrylamide monomers, aromatic vinyl monomers, and (meth)acrylonitrile. [2] The component according to [1], wherein the difference between the icing stress at -18°C and the icing stress at -8°C is 100 kPa or less. [3] The component according to [1] or [2], wherein the crosslinkable functional group (a) and the reactive functional group (b) are different groups. [4] The component according to any one of [1] to [3], wherein the surface occupancy of the graft chains of the graft polymer compound (A) is 0.05 or more and less than 0.75. [5] The component according to any one of [1] to [4], wherein the number average molecular weight (Mn) of the crosslinkable polymer compound (B) is 5,000 to 3,000,000. [6] The member according to any one of [1] to [5], wherein the crosslinkable functional group (a) and the reactive functional group (b) are each at least one functional group selected from the group consisting of a hydroxyl group, an isocyanate group, a blocked isocyanate group, and an alkoxysilyl group. [7] The member according to any one of [1] to [6], wherein the number average molecular weight (Mn) of the graft polymer compound (A) is 10,000 to 1,000,000.

[0006] According to the present invention, it is possible to provide a member that can effectively suppress ice nucleation, frost formation, and snow and ice accumulation.

[0007] FIG. 1 is a schematic diagram illustrating a test method for icing stress.

[0008] Hereinafter, an embodiment of the present invention (hereinafter referred to as "the present embodiment") will be described in detail. The present invention is not limited to the following description, and various modifications can be made within the scope of the present invention.

[0009] The member of this embodiment is a member for suppressing ice nucleation, frost formation, or snow and ice accumulation, having a coating film obtained by applying a coating composition containing a solvent and a polymer, wherein the polymer contains a structural unit represented by the following general formula (1), and comprises a graft polymer compound (A) having a crosslinkable functional group (a), and a crosslinkable polymer compound (B) having two or more reactive functional groups (b) that undergo a crosslinking reaction with the crosslinkable functional group (a), wherein the content of the crosslinkable polymer compound (B) is 0.1 mass% or more and less than 50 mass% out of a total of 100 mass% of the graft polymer compound (A) and the crosslinkable polymer compound (B), and wherein the member has an icing stress at -18°C of 150 kPa or less. (In the general formula (1), R １ represents a hydrogen atom or a methyl group, X represents O or NH, and R ２ represents any organic group, and R ３ and R ４ each independently represents a hydrogen atom, an alkyl group, an aryl group, or an acyl group, and R ３ and R ４ is bonded to a tertiary carbon atom or a quaternary carbon atom, n represents any number of repeating units, and Polymer represents a graft chain containing a constituent unit derived from at least one graft monomer selected from the group consisting of a (meth)acrylic acid-based monomer, a (meth)acrylamide-based monomer, an aromatic vinyl-based monomer, and (meth)acrylonitrile.

[0010] The member of this embodiment has excellent snow and ice accretion suppression effects, frost formation suppression effects, and ice nucleation suppression effects. The detailed reasons for these effects are not entirely clear, but are presumed to be due to the following. The member of this embodiment has a coating film obtained by applying a coating composition containing a solvent and a polymer. The graft-type polymer compound (A) and the crosslinkable polymer compound (B) contained in the coating composition are capable of crosslinking with each other. The crosslinking reaction between the graft-type polymer compound (A) and the crosslinkable polymer compound (B) can increase the mobility of the graft chains contained in the graft-type polymer compound (A), which is presumed to facilitate the creation of a supercooled state or an antifreeze state. Due to the presence of a coating film formed from such a coating composition, the member of this embodiment is presumed to have an interface with high mobility against ice, frost, snow, etc. Furthermore, the presence of a coating film formed from such a coating composition allows thermal movement of water without solidifying even below the freezing point, and is presumed to further lower the freezing temperature of water on the member surface.

[0011] The member of this embodiment is presumed to have an excellent snow and ice accretion suppression effect because water is less likely to freeze on the member surface, ice, frost, snow, etc. are less likely to form on the member surface, and furthermore, because it has an interface with high mobility against ice, frost, snow, etc., even if ice, frost, snow, etc. forms on the member surface, they slide off easily and are easily peeled off by external force.Furthermore, the member of this embodiment can further lower the freezing temperature of water inside or on the surface of the member, thereby lowering the temperature at which ice nuclei occur, and therefore has an excellent ice nucleation suppression effect.

[0012] <Coating Composition> First, the coating composition for forming the coating film that constitutes the member will be described below. The coating composition used in this embodiment contains a solvent and a polymer, and the polymer contains: a graft polymer compound (A) that contains a structural unit represented by the above general formula (1) and has a crosslinkable functional group (a), and a crosslinkable polymer compound (B) that has two or more reactive functional groups (b) that undergo a crosslinking reaction with the crosslinkable functional group (a) of the graft polymer compound (A).

[0013] (Graft Polymer Compound (A)) The graft polymer compound (A) has a structural unit represented by general formula (1). The graft polymer compound (A) preferably contains the structural unit represented by general formula (1) as a main component, and the content of the structural unit represented by general formula (1) is preferably 80 to 95 mol % from the viewpoint of the mechanical strength of the coating film and suppression of snow and ice adhesion. The graft polymer compound (A) is, for example, called a bottle-brush polymer or a cylinder polymer, and since the graft chains represented by Polymer in general formula (1) are bonded to the main chain at a high density, it not only has sufficient mobility but is also able to retain liquid substances and the like well.

[0014] In general formula (1), R １ is a hydrogen atom or a methyl group, and X is O or NH, so the main chain of the graft polymer is formed by polymerization of unsaturated groups such as (meth)acryloyloxy groups and (meth)acryloylamino groups. That is, the graft polymer compound (A) has a structure in which a graft chain (side chain) represented by Polymer is grafted to the main chain via a linking group. In addition, in general formula (1), X is preferably O, and the main chain of the graft polymer is preferably formed by polymerization of (meth)acryloyloxy groups.

[0015] The graft polymer compound (A) may contain a structural unit represented by general formula (1), and may also contain a structural unit (other structural unit) other than the structural unit represented by general formula (1). As the monomer constituting the other structural unit, a conventionally known radically polymerizable monomer having an unsaturated bond such as a vinyl group, a vinylidene group, or a vinylene group can be used.

[0016] In general formula (1), n ​​(the number of repeats) is preferably 2 or more, and more preferably 10 or more. By setting the number of n to 2 or more, the main chain is more likely to function as a polymer. The upper limit of n (the number of repeats) is not particularly limited, but is preferably 10,000 or less. The structural unit represented by general formula (1) may be a homopolymer or a random polymer containing other structural units. Furthermore, it may have a structure such as a block structure, a gradient structure, a graft structure, or a multi-branched structure.

[0017] Polymer in general formula (1) is a graft chain bonded (grafted) to the main chain, and contains a structural unit derived from at least one graft monomer selected from the group consisting of (meth)acrylic acid-based monomers, (meth)acrylamide-based monomers, aromatic vinyl-based monomers, and (meth)acrylonitrile.

[0018] Examples of (meth)acrylic acid monomers include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, butyl (meth)acrylate, 2-methylpropane (meth)acrylate, t-butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, lauryl (meth)acrylate, tetradecyl (meth)acrylate, octadecyl (meth)acrylate, behemoglobin, and the like. aliphatic, alicyclic, and aromatic alkyl (meth)acrylates such as methylcyclohexane (meth)acrylate, isostearyl (meth)acrylate, cyclohexyl (meth)acrylate, t-butylcyclohexylmethyl (meth)acrylate, isobornyl (meth)acrylate, trimethylcyclohexyl (meth)acrylate, cyclodecyl (meth)acrylate, cyclodecylmethyl (meth)acrylate, benzyl (meth)acrylate, t-butylbenzotriazole phenylethyl (meth)acrylate, phenyl (meth)acrylate, naphthyl (meth)acrylate, and allyl (meth)acrylate;

[0019] (meth)acrylates having a hydroxyl group, such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, cyclohexanedimethanol mono(meth)acrylate, and cyclohexanediol mono(meth)acrylate;

[0020] Mono(meth)acrylates of polyalkylene glycols such as poly(n=2 or more) ethylene glycol mono(meth)acrylate, poly(n=2 or more) propylene glycol mono(meth)acrylate, poly(n=2 or more) tetramethylene glycol mono(meth)acrylate, mono(meth)acrylates of mono- or poly(n=2 or more) ethylene glycol mono- or poly(n=2 or more) propylene glycol random copolymers, and mono(meth)acrylates of mono- or poly(n=2 or more) ethylene glycol mono- or poly(n=2 or more) propylene glycol block copolymers;

[0021] (poly)ethylene glycol monomethyl ether (meth)acrylate, (poly)ethylene glycol monooctyl ether (meth)acrylate, (poly)ethylene glycol monolauryl ether (meth)acrylate, (poly)ethylene glycol monostearyl ether (meth)acrylate, (poly)ethylene glycol monooleyl ether (meth)acrylate, (poly)ethylene glycol monostearate (meth)acrylate, (poly)ethylene glycol monononylphenyl ether (meth)acrylate, (poly)propylene glycol monomethyl ether (meth)acrylate, (poly)propylene glycol monoethyl ether (meth)acrylate, (poly)propylene glycol monooctyl ether (meth)acrylate, (poly)propylene glycol monolauryl ether (meth)acrylate, (poly)ethylene glycol (poly)propylene glycol monomethyl ether (meth)acrylate, and other (poly)ethylene glycol (poly)propylene glycol monomethyl ether (meth)acrylate mono(meth)acrylates of (polyalkylene)glycol monoalkyl, alkylene, alkyne ether or esters;

[0022] (Meth)acrylic acid-based monomers having a carboxy group, such as monomers obtained by reacting acrylic acid, methacrylic acid, or hydroxyalkyl (meth)acrylate with an acid anhydride such as maleic anhydride, succinic anhydride, or phthalic anhydride; (meth)acrylic acid-based monomers having a sulfonic acid group, such as ethyl sulfonate (meth)acrylate; (meth)acrylic acid-based monomers having a phosphoric acid group, such as (di, tri)(meth)acryloyloxyethyl phosphate ester;

[0023] oxygen atom-containing (meth)acrylates such as glycidyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, oxetanylmethyl (meth)acrylate, morpholino (meth)acrylate, methylmorpholino (meth)acrylate, and methylmorpholinoethyl (meth)acrylate;

[0024] (meth)acrylates having an amino group, such as 2-aminoethyl (meth)acrylate, t-butylaminoethyl (meth)acrylate, tetramethylpiperidyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, pentamethylpiperidyl (meth)acrylate, N-ethylmorpholino (meth)acrylate, trimethylaminoethyl (meth)acrylate chloride, diethylmethylaminoethyl (meth)acrylate chloride, benzyldimethylaminoethyl (meth)acrylate chloride, and trimethylaminoethyl (meth)acrylate methyl sulfate;

[0025] Isocyanate group-containing (meth)acrylates such as (meth)acryloyloxyethyl isocyanate and (meth)acryloyloxyethoxyethyl isocyanate; blocked isocyanate-containing (meth)acrylates in which the isocyanate group of an isocyanate group-containing (meth)acrylate is blocked with caprolactone, a pyrazole compound, MEK oxime, or the like;

[0026] Alkoxysilyl group-containing (meth)acrylates such as 3-(trimethoxysilyl)propyl (meth)acrylate, 3-(triethoxysilyl)propyl (meth)acrylate, 3-(meth)acryloxypropylmethyldimethoxysilane, and 3-(meth)acryloxypropylmethyldiethoxysilane; and the like.

[0027] Examples of the (meth)acrylamide monomer include (meth)acrylamide, N,N-dimethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, N-hydroxyethyl(meth)acrylamide, and (meth)acryloylmorpholine.

[0028] Examples of aromatic vinyl monomers include styrene, vinyltoluene, vinylhydroxybenzene, chloromethylstyrene, vinylnaphthalene, vinylbiphenyl, vinylethylbenzene, vinyldimethylbenzene, and α-methylstyrene.

[0029] In general formula (1), R ２ represents an arbitrary organic group. Examples of the arbitrary organic group include alkylene groups such as ethylene and propylene; cycloalkylene groups such as cyclohexylene; poly(n = 2 or more) alkylene glycol groups; polyester groups obtained by reacting or polymerizing a terminal hydroxyl group of a poly(n = 2 or more) alkylene glycol group with a hydroxyalkylcarboxylic acid; organic groups in which a group such as a hydroxyl group or an acyl group is bonded to any position of these groups; and groups in which these groups are bonded via a urethane bond, urea bond, or the like. Among these, alkylene groups such as ethylene, propylene, butylene, and methylpropylene; polyethylene glycol, propylene glycol, and the like are preferred because of their high versatility and easy availability.

[0030] In general formula (1), R ３ and R ４ each independently represents a hydrogen atom, an alkyl group, an aryl group, or an acyl group. ３ and R ４ The carbon atom to which R is attached is a tertiary or quaternary carbon atom. ２Specific examples of the ester group bonded to the group include groups represented by the following formulas (1-1) to (1-6). In the following formulas (1-1) to (1-6), "*" represents R ２ The bond position is shown.

[0031] The number-average molecular weight (Mn) of the graft polymer compound (A) is preferably 10,000 to 1,000,000, more preferably 20,000 to 800,000, and even more preferably 30,000 to 500,000. The molecular weight distribution (dispersity index PDI = Mw / Mn) of the graft polymer compound (A) is preferably 1.0 to 3.0, more preferably 1.3 to 3.0, and even more preferably 1.6 to 2.5. Having the number-average molecular weight of the graft polymer compound (A) within the above range effectively prevents the viscosity of the coating composition from becoming too high, making it difficult to apply to a substrate, while allowing the performance derived from the specific structure of the graft polymer compound (A) to be fully exhibited. The number-average molecular weight (Mn) and molecular weight distribution (dispersity index PDI) of the graft polymer compound (A) can be determined, for example, by gel permeation chromatography (GPC) measurement in terms of polymethyl methacrylate.

[0032] The graft polymer compound (A) may be either one in which the molecular weight of the polymer in general formula (1) that forms the graft chain is small and the number of graft chains is large; or one in which the molecular weight of the polymer in general formula (1) that forms the graft chain is large and the number of graft chains is small; however, a case in which the molecular weight of the polymer in general formula (1) that forms the graft chain is small and the number of graft chains is large is preferred because it is easier to control the surface occupancy within a suitable range, and the graft chain length is desirably 10 to 40 monomers.

[0033] The graft polymer compound (A) also has a crosslinkable functional group (a). The crosslinkable functional group (a) may be any functional group exhibiting crosslinkability, and is not particularly limited thereto. Examples of the crosslinkable functional group (a) include a carboxyl group, a phosphate group, a phosphate ester group, a hydroxyl group, a glycidyl group, an isocyanate group, a blocked isocyanate group, an alkoxysilyl group, a (meth)acryloyl group, and a halogen atom. Among these, from the viewpoint of further enhancing the effects of the present invention, a hydroxyl group, an isocyanate group, a blocked isocyanate group, and an alkoxysilyl group are preferred, a hydroxyl group, an isocyanate group, and a blocked isocyanate group are more preferred, and a hydroxyl group and a blocked isocyanate are even more preferred. Examples of the alkoxysilyl group include a trimethoxysilyl group, a triethoxysilyl group, and a tripropoxysilyl group.

[0034] The crosslinkable functional group (a) is introduced to crosslink with the reactive functional group (b) contained in the crosslinkable polymer compound (B) described later. By using the graft polymer compound (A) having the crosslinkable functional group (a) in combination with the crosslinkable polymer compound (B) having two or more reactive functional groups (b) that undergo a crosslinking reaction with the crosslinkable functional group (a), the coating film formed using the coating composition of the present invention can be one in which the mobility of the graft chains contained in the graft polymer compound (A) is enhanced, and thus ice nucleation, frost formation, and snow and ice accumulation can be effectively suppressed on a member having such a coating film.

[0035] The crosslinkable functional group (a) may be contained in either the polymer main chain or the graft chain in the graft polymer compound (A). However, from the viewpoint of reactivity, it is preferably contained in the graft chain, and more preferably contained in the polymer chain represented by Polymer in general formula (1). The method for introducing the crosslinkable functional group (a) into the graft polymer compound (A) is not particularly limited, and examples thereof include a method using a monomer having the crosslinkable functional group (a) as a monomer for introducing the graft chain. For example, when the crosslinkable functional group (a) is a hydroxyl group, examples thereof include a method using a (meth)acrylate having a hydroxyl group or a mono(meth)acrylate of a polyalkylene glycol. When the crosslinkable functional group (a) is an isocyanate group or a blocked isocyanate group, a method using an isocyanate group-containing (meth)acrylate or a blocked isocyanate group-containing (meth)acrylate can be used, and when the crosslinkable functional group (a) is an alkoxysilyl group, a method using an alkoxysilyl group-containing (meth)acrylate can be used. The method for introducing the crosslinkable functional group (a) into the graft polymer compound (A) may be a method of introducing the functional group by modification after the preparation of the graft polymer.

[0036] The amount of the structural unit derived from the monomer having the crosslinkable functional group (a) in the graft chain is not particularly limited, but is preferably 1 to 20 mol %, more preferably 5 to 10 mol %.

[0037] Furthermore, in the graft polymer compound (A), when the main chain is taken as the central axis, the graft chains are extended linearly from the central axis, and a plane including the ends of the graft chains (virtual outer periphery) is imagined, the external shape of the graft polymer compound (A) can be regarded as a cylinder with the plane including the ends as the side. In the graft polymer compound (A) having such an external shape, the longer the graft chains are, the lower the density of the graft chains on the side, and the higher the structural freedom of the graft chains. As a result, the graft chains can be freely folded.

[0038] In the graft polymer compound (A), the surface occupancy of the graft chains (σ ＊) can be calculated by the following formula:

[0039] In the above formula, DP ｎ，ｇｒａｆｔ is the number-average degree of polymerization of the graft chains, x is the number of graft chains per unit length of the backbone polymer (number / nm), r is the radius of the backbone polymer (nm) (for example, 0.8 nm for poly(2-(2-bromoisobutyryloxy)ethyl methacrylate) (PBIEM)), a ２ is the cross-sectional area of ​​the monomer (nm ２ ) (e.g., 3.3 nm for methoxypoly(ethylene glycol) methacrylate (PEGMA) ２ ), l is the total length of the repeating unit of the polymer chain (nm) (e.g., 0.25 for polymethacrylate), and 2π(DP ｎ，ｇｒａｆｔ l + r) is the circumference (nm) of the cross section of the graft polymer compound (A), and l / x is the distance (nm) between adjacent graft chains. For the above method, see Biomacromolecules, 2021, 22, 2505-14.

[0040] The surface occupancy of the grafted chains is a value between 0 and 1. The larger the value, the larger the proportion of the ends of the grafted chains on the side of the polymer, and the more restricted the degree of freedom of the grafted chains. In other words, the surface occupancy of the grafted chains is a value that reflects the degree of freedom of the grafted chains, and the surface occupancy of the grafted chains (σ ＊ The higher the graft chain's structural freedom is, the more restricted it becomes. As a result, the graft chains can maintain a state of extending in a direction approximately perpendicular to the main chain, which is thought to result in the properties specific to that structure.

[0041] The surface occupancy of the graft chains of the graft polymer compound (A) is preferably 0.05 or more and less than 0.75, more preferably 0.10 or more and 0.65 or less, and even more preferably 0.20 or more and 0.50 or less. When the surface occupancy is within the above range, the density of the graft chains is in an appropriate range, thereby improving the retention of liquid substances (especially for liquid substances that are immiscible with water, the retention is greatly improved), and further improving the suppression of ice nucleation due to the size exclusion effect.

[0042] The density of the graft chains of the graft polymer compound (A) is 0.01 chains / nm ２ It is preferable that the number of chains is 0.05 chains / nm or more. ２ More preferably, it is 0.1 chains / nm or more. ２ More preferably, it is 0.2 chains / nm or more. ２ The upper limit is not particularly limited, but is preferably 1.0 chain / nm. ２ and can be less than or equal to 0.9 chains / nm ２ It can also be the following:

[0043] The graft polymer compound (A) can be produced, for example, by polymerizing a polymer containing a structural unit derived from a monomer represented by the following general formula (2) with at least one graft monomer selected from the group consisting of (meth)acrylic acid-based monomers, (meth)acrylamide-based monomers, aromatic vinyl-based monomers, and (meth)acrylonitrile in the presence of a copper catalyst or in the presence of at least one of a quaternary ammonium salt and a quaternary phosphonium salt that generate chloride ions, bromide ions, or iodide ions: (In the above general formula (2), R １ ~R ４ and X is R in the general formula (1). １ ~R ４ and X, and Y represents a chlorine atom, a bromine atom, or an iodine atom.

[0044] In general formula (2), the group represented by Y (halogen atom) becomes a radical and is eliminated, and the carbon atom to which the halogen atom was bonded becomes a radical. The generated carbon atom radical then reacts with the graft monomer to generate a radical. The detached halogen radical immediately bonds to the generated radical, stabilizing it. By stabilizing the generated radical in this manner, termination reactions due to coupling between radicals and the like are less likely to occur. As a result, the graft monomer undergoes sequential polymerization to form a graft chain represented by Polymer in general formula (1), thereby obtaining the desired graft polymer. Here, by using a graft monomer containing a crosslinkable functional group (a), the crosslinkable functional group (a) can be introduced into the polymer chain represented by Polymer in general formula (1).

[0045] Alternatively, the desired graft polymer compound (A) can also be produced by polymerizing a macromonomer represented by the following general formula (4): However, since the reaction site of the macromonomer represented by the following general formula (4) is present at the polymer end, unpolymerized macromonomers tend to remain and the molecular weight of the resulting polymer is unlikely to increase. (In the above general formula (4), R １ ~R ４ , X, and Polymer are R in the above general formula (1). １ ~R ４ , X, and Polymer.)

[0046] In contrast, the above-described method using a polymer containing a structural unit derived from the monomer represented by the general formula (2) (hereinafter also referred to as an "initiator polymer") makes it possible to efficiently produce the desired graft polymer compound (A).

[0047] A specific example of the monomer represented by the above general formula (2) is a monomer represented by the following general formula (3). (In the above general formula (3), R １ and R ２ represents R in the general formula (1). １ and R ２ is synonymous with

[0048] The monomer represented by the general formula (3) may be commercially available or synthesized. For example, the monomer represented by the general formula (3) can be synthesized by reacting a (meth)acrylate having a hydroxyl group or a glycidyl group with 2-bromo-2-methylpropionic acid (2-bromoisobutyric acid).

[0049] Furthermore, a polymer (initiator group polymer) containing a constituent unit derived from a monomer represented by the above general formula (2) can also be obtained by polymerizing a (meth)acrylate having a hydroxyl group or a glycidyl group, and then reacting the polymer with a carboxylic acid or a derivative thereof having Y (a chlorine atom, a bromine atom, or an iodine atom).

[0050] As the copper catalyst, a copper complex is preferably used, more preferably a complex of a monovalent copper compound and an organic ligand is used, and even more preferably a combination of a monovalent copper compound and an organic ligand complex and a divalent copper compound and an organic ligand complex is used. Examples of monovalent copper compounds include cuprous chloride and cuprous bromide, and examples of divalent copper compounds include cupric chloride and cupric bromide. Examples of organic ligands include 2,2'-bipyridyl or a derivative thereof, 1,10-phenanthroline or a derivative thereof, polyamines (e.g., tetramethylethylenediamine, pentamethyldiethylenetriamine, hexamethyltris(2-aminoethyl)amine), and polycyclic alkaloids such as L-(-)-sparteine. These copper compounds and organic ligands may be used alone or in combination of two or more. When both a monovalent copper compound and a divalent copper compound are used, the molar ratio of the monovalent copper compound to the divalent copper compound, based on copper, is preferably 1 or more, more preferably 2 or more, and may be 100 or less, or may be 50 or less. When adding a copper complex in radical polymerization, the copper complex may be formed in advance and then used in radical polymerization, or the copper compound and the organic ligand may be added in a ratio that forms a copper complex and then radical polymerization may be performed. The ratio of the copper compound and the organic ligand added in radical polymerization is preferably 1 to 3 times, more preferably 1.5 to 2.5 times, the molar number of the organic ligand relative to the molar number of the copper compound, since the organic ligand is sufficiently coordinated to the copper compound and the copper complex is well dissolved.

[0051] As the quaternary ammonium salt or quaternary phosphonium salt, a conventionally known compound can be used. These quaternary salts are preferably soluble in the polymerization solvent. These quaternary salts may be appropriately selected depending on the type of monomer and polymerization solvent used.

[0052] Examples of quaternary ammonium salts include tetramethylammonium salts, tetraethylammonium salts, tetrabutylammonium salts, methylimidazolium salts, methylpyridinium salts, etc. Examples of quaternary phosphonium salts include tetrabutylphosphonium salts, tributylmethylphosphonium salts, triphenylmethylphosphonium salts, etc.

[0053] When a graft monomer is reacted with an initiator polymer in the presence of an equimolar or more amount of a copper catalyst (having an equimolar or more number of copper atoms) or an equimolar or more amount of a quaternary salt, all initiator groups undergo halogen exchange to form graft chains, thereby obtaining the desired graft-type polymer compound (A).

[0054] The graft polymer is preferably produced by solution polymerization in the presence of a polymerization solvent such as an organic solvent. Examples of polymerization solvents that can be used include anisole, hydrocarbon solvents, ketone solvents, alcohol solvents, glycol solvents, amide solvents, ester solvents, urea solvents, and ionic liquids. Among these, it is preferable to use at least a highly polar solvent that can dissolve the copper complex or quaternary salt and cause halogen exchange. Examples of such polymerization solvents include anisole; alcohol solvents such as methanol, ethanol, and isopropanol; glycol solvents such as ethylene glycol, propylene glycol, glycerin, diethylene glycol, and propylene glycol monomethyl ether; amide solvents such as dimethylformamide, dimethylacetamide, N-methylpyrrolidone, 3-methoxy-N,N-dimethylpropanamide, and 3-butoxy-N,N-dimethylpropanamide; sulfoxide solvents such as dimethyl sulfoxide; and ionic liquids such as imidazolium salts and quaternary ammonium salts.

[0055] The amount of polymerization solvent used during polymerization is preferably 30 to 80% by mass, more preferably 40 to 70% by mass, based on the entire polymerization reaction system. If the amount of polymerization solvent is less than 30% by mass, the amount of solids may be too high, resulting in an excessively high viscosity. On the other hand, if the amount of polymerization solvent is more than 80% by mass, the monomer concentration may be too low, resulting in a decreased polymerization rate. The graft polymer compound (A) may be used as is (as dissolved in the polymerization solvent), or it may be precipitated in a poor solvent, extracted, and then dissolved in another solvent for use.

[0056] The graft polymer compound (A) can also be produced by forming a graft polymer as an intermediate by the same method as above, and then modifying the graft chain. For example, by forming a graft polymer as an intermediate by the same method as above (wherein the graft chain is a precursor of the polymer chain represented by Polymer in general formula (1)), the graft chain can be modified using a compound containing a crosslinkable functional group (a), thereby forming a graft chain containing the crosslinkable functional group (a) (the polymer chain represented by Polymer in general formula (1)). In this method, the graft polymer as an intermediate (and the graft monomer for forming it) does not need to contain the crosslinkable functional group (a).

[0057] The method for modifying the graft chain is not limited. For example, when a graft monomer for forming a graft polymer as an intermediate is referred to as a first graft monomer, after obtaining the graft polymer as an intermediate, the graft chain may be extended by further carrying out a graft polymerization reaction using a second graft monomer different from the first graft monomer. As the second graft monomer, it is preferable to use at least one graft monomer selected from the group consisting of (meth)acrylic acid-based monomers, (meth)acrylamide-based monomers, aromatic vinyl-based monomers, and (meth)acrylonitrile. Furthermore, it is preferable to use as the second graft monomer one containing a crosslinkable functional group (a).

[0058] (Crosslinkable Polymer Compound (B)) Next, the crosslinkable polymer compound (B) will be described. The crosslinkable polymer compound (B) is a polymer having two or more reactive functional groups (b) that undergo a crosslinking reaction with the crosslinkable functional group (a) contained in the above-mentioned graft type polymer compound (A).

[0059] The reactive functional group (b) may be any group capable of crosslinking with the crosslinkable functional group (a), and is not particularly limited thereto. Examples include a carboxyl group, a phosphate group, a phosphate ester group, a hydroxyl group, a glycidyl group, an isocyanate group, a blocked isocyanate group, an alkoxysilyl group, a (meth)acryloyl group, and a halogen atom. Among these, from the viewpoint of further enhancing the effects of the present embodiment, a hydroxyl group, an isocyanate group, a blocked isocyanate group, and an alkoxysilyl group are preferred, a hydroxyl group, an isocyanate group, and a blocked isocyanate group are more preferred, and a hydroxyl group and a blocked isocyanate group are even more preferred. Examples of alkoxysilyl groups include a trimethoxysilyl group, a triethoxysilyl group, and a tripropoxysilyl group. For example, when the crosslinkable functional group (a) is a hydroxyl group, the reactive functional group (b) can be an isocyanate group or a blocked isocyanate group. Furthermore, when the crosslinkable functional group (a) is an isocyanate group or a blocked isocyanate group, the reactive functional group (b) can be a hydroxyl group, and further, when the crosslinkable functional group (a) is an alkoxysilyl group, the reactive functional group (b) can be an alkoxysilyl group.

[0060] In this embodiment, by making the crosslinkable polymer compound (B) contain two or more reactive functional groups (b) capable of undergoing a crosslinking reaction with the crosslinkable functional group (a), the multiple graft-type polymer compounds (A) can be suitably crosslinked together by the crosslinkable polymer compound (B), thereby increasing the mobility of the graft chains contained in the graft-type polymer compound (A). As a result, ice nucleation, frost formation, and snow and ice accumulation can be effectively suppressed on a member provided with a coating film formed using the coating composition of this embodiment.

[0061] The crosslinkable polymer compound (B) may contain two or more reactive functional groups (b). Examples of the crosslinkable polymer compound (B) include copolymers of a monomer having a reactive functional group (b) with a monomer copolymerizable with such a monomer; biologically derived polymers such as cellulose nanofibers, chitosan, and polylactic acid; and the like. When the crosslinkable polymer compound (B) is the above-mentioned copolymer, from the viewpoint of crosslinkability, it preferably contains 1 to 20 mol% of structural units derived from a monomer having a reactive functional group (b), and more preferably contains 5 to 10 mol% of structural units derived from a monomer having a reactive functional group (b). The biologically derived polymer, such as cellulose nanofiber, used as the crosslinkable polymer compound (B) is preferably one whose dispersion stability in a solvent has been improved, if necessary, by oxidation treatment or the like.

[0062] Furthermore, the reactive functional group (b) may be any group capable of crosslinking with the crosslinkable functional group (a) contained in the graft polymer compound (A). The reactive functional group (b) may be the same group as the crosslinkable functional group (a) or a different group. However, from the viewpoint of further enhancing the effect of suppressing ice nucleation, frost formation, and snow and ice accumulation, it is preferable that the crosslinkable functional group (a) and the reactive functional group (b) are different groups. More specifically, it is preferable that the crosslinkable functional group (a) and the reactive functional group (b) are different groups, and that while a crosslinkable reaction is possible between the crosslinkable functional group (a) and the reactive functional group (b), a crosslinkable reaction does not occur between either the crosslinkable functional groups (a) or the reactive functional groups (b). As a combination of the crosslinkable functional group (a) and the reactive functional group (b), it is preferable that the crosslinkable functional group (a) is a hydroxyl group and the reactive functional group (b) is an isocyanate group or a blocked isocyanate.

[0063] The number-average molecular weight (Mn) of the crosslinkable polymer compound (B) is not particularly limited, but from the viewpoint of further enhancing the effects of suppressing ice nucleation, frost formation, and snow and ice accumulation, it is preferably 5,000 to 3,000,000, more preferably 10,000 to 1,000,000, and even more preferably 15,000 to 500,000. By having the molecular weight of the crosslinkable polymer compound (B) within the above range, the resulting coating film can have appropriate strength. Furthermore, the molecular weight distribution (dispersity index PDI = Mw / Mn) of the crosslinkable polymer compound (B) is preferably 1.0 to 4.0, more preferably 1.2 to 3.0. The number-average molecular weight (Mn) and molecular weight distribution (dispersity index PDI) of the crosslinkable polymer compound (B) can be determined, for example, by gel permeation chromatography (GPC) measurement in terms of polymethyl methacrylate. The crosslinkable polymer compound (B) may be a linear polymer having no graft chains (for example, a linear polymer having an average molecular weight of side chains of 600 or less). The mass average molecular weight (Mw) may also be determined by multiplying the number average molecular weight (Mn) determined by gel permeation chromatography (GPC) measurement in terms of polymethyl methacrylate by the molecular weight distribution (dispersity index PDI=Mw / Mn).

[0064] The method for producing the crosslinkable polymer compound (B) is not particularly limited. For example, when the crosslinkable polymer compound (B) has a structural unit derived from a monomer having a reactive functional group (b), the crosslinkable polymer compound (B) can be produced by copolymerizing a monomer having the reactive functional group (b) with a monomer copolymerizable with such a monomer.

[0065] The monomer having the reactive functional group (b) and the copolymerizable monomer can be the same as those exemplified above as the monomer for forming the graft chain of the graft polymer compound (A), i.e., the (meth)acrylic acid-based monomer, (meth)acrylamide-based monomer, aromatic vinyl-based monomer, and (meth)acrylonitrile-based monomer exemplified above as the monomer for forming the graft chain of the graft polymer compound (A). For example, the (meth)acrylic acid-based monomer may be any of the aliphatic, alicyclic, and aromatic alkyl (meth)acrylates; (meth)acrylates having a hydroxyl group; mono(meth)acrylates of polyalkylene glycols; mono(meth)acrylates of (polyalkylene)glycol monoalkyls, alkylenes, and alkyne ethers or esters; (meth)acrylic acid-based monomers; (meth)acrylic acid-based monomers having a sulfonic acid group; (meth)acrylic acid-based monomers having a phosphoric acid group; oxygen atom-containing (meth)acrylates; (meth)acrylates having an amino group; isocyanate group-containing (meth)acrylates; blocked isocyanate-containing (meth)acrylates; and alkoxysilyl group-containing (meth)acrylates.

[0066] For example, when the reactive functional group (b) is an isocyanate group or a blocked isocyanate group, the crosslinkable polymer compound (B) may be produced by using an isocyanate group-containing (meth)acrylate or a blocked isocyanate-containing (meth)acrylate as the monomer having the reactive functional group (b) and copolymerizing a monomer not having the reactive functional group (b) (for example, an aliphatic, alicyclic, or aromatic alkyl (meth)acrylate, or a (polyalkylene) glycol monoalkyl, alkylene, alkyne ether, or ester mono(meth)acrylate, etc.) as the copolymerizable monomer. Furthermore, when the reactive functional group (b) is a hydroxyl group, the crosslinkable polymer compound (B) may be produced by using a (meth)acrylate having a hydroxyl group or a mono(meth)acrylate of a polyalkylene glycol as the monomer having the reactive functional group (b) and copolymerizing a monomer not having the reactive functional group (b) as the copolymerizable monomer. Furthermore, when the reactive functional group (b) is an alkoxysilyl group, the crosslinkable polymer compound (B) may be produced by using an alkoxysilyl group-containing (meth)acrylate as the monomer having the reactive functional group (b) and copolymerizing a monomer not having the reactive functional group (b) as the copolymerizable monomer.

[0067] In this case, from the viewpoint of affinity with the graft polymer compound (A), it is preferable to use a monomer having the same or similar skeleton as the graft chain constituting the graft polymer compound (A) as the copolymerizable monomer. For example, when the graft chain constituting the graft polymer compound (A) is obtained by polymerizing a mono(meth)acrylate having a polyalkylene glycol skeleton, it is preferable to use a mono(meth)acrylate having a polyalkylene glycol skeleton as the copolymerizable monomer for forming the crosslinkable polymer compound (B). The reactive functional group (b) of the crosslinkable polymer compound (B) may be a functional group derived from the monomer used in the above method, or may be a functional group introduced by modification using the functional group of the monomer used in the above method.

[0068] The content ratio of the structural unit derived from the monomer having the reactive functional group (b) and the structural unit derived from the copolymerizable monomer in the crosslinkable polymer compound (B) is not particularly limited and may be appropriately selected depending on the number average molecular weight of the crosslinkable polymer compound (B) and the amount of the reactive functional group (b) to be introduced. However, the molar ratio of "structural unit derived from the monomer having the reactive functional group (b):structural unit derived from the copolymerizable monomer" is preferably 1:100 to 20:100, more preferably 3:100 to 10:100, and even more preferably 5:100 to 10:100.

[0069] When producing the crosslinkable polymer compound (B), it is preferable to produce the crosslinkable polymer compound (B) by solution polymerization in the presence of a polymerization solvent such as an organic solvent. Examples of polymerization solvents that can be used include anisole, hydrocarbon solvents, ketone solvents, alcohol solvents, glycol solvents, amide solvents, ester solvents, urea solvents, and ionic liquids. Among these, it is preferable to use at least a highly polar solvent that can dissolve the quaternary salt and cause halogen exchange. Examples of such polymerization solvents include alcohol solvents such as anisole, methanol, ethanol, and isopropanol; glycol solvents such as ethylene glycol, propylene glycol, glycerin, diethylene glycol, and propylene glycol monomethyl ether; amide solvents such as dimethylformamide, dimethylacetamide, N-methylpyrrolidone, 3-methoxy-N,N-dimethylpropanamide, and 3-butoxy-N,N-dimethylpropanamide; sulfoxide solvents such as dimethyl sulfoxide; and ionic liquids such as imidazolium salts and quaternary ammonium salts.

[0070] The amount of polymerization solvent used during polymerization is preferably 30 to 80% by mass, more preferably 40 to 70% by mass, based on the entire polymerization reaction system. If the amount of polymerization solvent is less than 30% by mass, the amount of solids may be too high, resulting in excessively high viscosity. On the other hand, if the amount of polymerization solvent is more than 80% by mass, the monomer concentration may be too low, resulting in a decrease in polymerization rate. The crosslinkable polymer compound (B) may be used as is (as dissolved in the polymerization solvent), or it may be precipitated in a poor solvent, extracted, and then dissolved in another solvent for use. Furthermore, known polymerization initiators may be used as appropriate.

[0071] (Solvent) The coating composition used in this embodiment contains a solvent. As the solvent, for example, in addition to the organic solvents that can be used in the solution polymerization, water can also be used. Specific examples of the solvent include anisole; alcohol-based solvents such as methanol, ethanol, and isopropanol; glycol-based solvents such as ethylene glycol, propylene glycol, glycerin, diethylene glycol, and propylene glycol monomethyl ether; amide-based solvents such as dimethylformamide, dimethylacetamide, N-methylpyrrolidone, 3-methoxy-N,N-dimethylpropanamide, and 3-butoxy-N,N-dimethylpropanamide; ionic liquids such as imidazolium salts and quaternary ammonium salts; hydrocarbon-based solvents such as toluene, xylene, hexane, isoparaffin, and anisole; ketone-based solvents such as methyl ethyl ketone and methyl isobutyl ketone; ester-based solvents such as ethyl acetate, propyl acetate, butyl acetate, ethylene glycol dilaurate, and trimethylolpropane triacetate; and esters of glycol-based solvents such as propylene glycol monomethyl ether acetate and 3-methoxy-3-methyl-1-butyl acetate.

[0072] (Method for Preparing Coating Composition) The coating composition of the present embodiment can be prepared by mixing a polymer containing the above-described graft type polymer compound (A) and crosslinkable polymer compound (B) with a solvent.

[0073] In the coating composition of this embodiment, the content of the crosslinkable polymer compound (B) is 0.1% by mass or more and less than 50% by mass, preferably 0.5 to 40% by mass, and more preferably 1 to 30% by mass, based on the total 100% by mass of the graft-type polymer compound (A) and the crosslinkable polymer compound (B). When the crosslinkable polymer compound (B) is a cellulose nanofiber, the content is more preferably 20% by mass or less, particularly preferably 15% by mass or less, and most preferably 12% by mass or less. If the content of the crosslinkable polymer compound (B) is too little or too much, the effect of suppressing ice nucleation, frost formation, and snow and ice accumulation on the resulting member will be insufficient.

[0074] The content of the polymer containing the graft type polymer compound (A) and the crosslinkable polymer compound (B) in the coating composition of the present embodiment is not particularly limited, but from the viewpoint of coating film formability, it is preferably 1 to 20 mass %, more preferably 2 to 10 mass %.

[0075] The coating composition of this embodiment may also contain a catalyst for crosslinking the crosslinkable functional group (a) of the graft polymer compound (A) with the reactive functional group (b) of the crosslinkable polymer compound (B). The catalyst may be appropriately selected depending on the types of the crosslinkable functional group (a) and the reactive functional group (b). When either the crosslinkable functional group (a) or the reactive functional group (b) is a hydroxyl group and the other is an isocyanate group or a blocked isocyanate group, organic tin compounds such as dibutyltin dilaurate and dioctyltin dilaurate; metal catalysts such as bismuth compounds; base catalysts such as organic amines; urethane reaction catalysts such as DMC catalysts; and the like can be used. When both the crosslinkable functional group (a) and the reactive functional group (b) are trialkoxysilyl groups, base catalysts or acid catalysts can be used.

[0076] The coating composition of the present embodiment may be a composition for forming a substantially transparent (clear) coating film, and may contain various additives as needed, such as colorants such as dyes and pigments, pigment dispersants, antifoaming agents, leveling agents, preservatives, UV absorbers, light stabilizers, thickeners, photoinitiators, photoacid generators, photobase generators, photosensitizers, antibacterial agents, antifungal agents, antifogging agents, water repellents, antistatic agents, conductive agents, reinforcing materials, fibrous materials, and other polymer components.

[0077] <Component> The component of this embodiment is a component for suppressing ice nucleation, frost formation, or snow and ice accumulation, which has a coating film obtained by applying the coating composition described above, and has an icing stress of 150 kPa or less at −18° C.

[0078] The member of this embodiment is formed, for example, by applying the above-described coating composition to a substrate (carrier). The substrate (carrier) is not particularly limited, and can be appropriately selected from organic materials, inorganic materials, metal materials, etc.

[0079] The organic material is not particularly limited, and various resins and rubbers can be used without limitation. The resin may be either a thermosetting resin or a thermoplastic resin. Examples of thermosetting resins include epoxy resins, phenolic resins, amino resins, unsaturated polyester resins, polyurethane resins, urea resins, melamine resins, thermosetting polyimide resins, and diallyl phthalate resins. Examples of thermoplastic resins include polyolefin-based resins such as polyethylene, polypropylene, polystyrene, and polycycloolefin; vinyl-based resins such as polystyrene, acrylic resins, polyvinyl chloride resins, and polyvinyl alcohol; fluorine-based resins such as polytetrafluoroethylene; polyester-based resins such as polyethylene terephthalate, polybutylene terephthalate, polytrimethylene terephthalate, and polyethylene naphthalate; and silicone resins such as polydimethylsiloxane. Examples of rubber include diene-based rubbers such as butadiene rubber, styrene-butadiene rubber, chloroprene rubber, isoprene rubber, natural rubber, nitrile rubber, and butyl rubber; and rubbers other than diene-based rubbers such as ethylene propylene rubber, acrylic rubber, polyether rubber, polyurethane rubber, fluororubber, and silicone rubber.

[0080] The type of substrate is also not particularly limited, and examples include tubes, sheets, fibers, strips, films, plates, foils, membranes, pellets, powders, particles, and molded products (for example, extrusion molded products, casting molded products, etc.).

[0081] The substrate may have affinity for the graft polymer compound (A) and / or the crosslinkable polymer compound (B), or may have been surface-treated to enhance affinity for the graft polymer compound (A) and / or the crosslinkable polymer compound (B). For example, the substrate may be surface-treated with a silane coupling agent such as 3-(2-aminoethylaminopropyl)trimethoxysilane. Furthermore, a primer layer may be formed on the substrate to enhance affinity for the graft polymer compound (A) and / or the crosslinkable polymer compound (B). The primer layer may be, for example, a layer made of the crosslinkable polymer compound (B).

[0082] Furthermore, when forming a coating film made of the coating composition on a substrate, a composition may be prepared by mixing the above-mentioned graft polymer compound (A) and a solvent in a solution containing a polymerization initiator and a monomer for forming the crosslinkable polymer compound (B), applying such a composition to the substrate to form a coating film layer, and then polymerizing the monomer for forming the crosslinkable polymer compound (B) in the solution of the graft polymer compound (A) and a solvent in the coating film layer on the substrate to form the crosslinkable polymer compound (B) (i.e., the crosslinkable polymer compound (B) may be formed in situ), thereby forming a layer made of the coating composition of the present invention.

[0083] Furthermore, the coating film formed on the substrate may retain a liquid substance. Examples of the liquid substance include water, ionic liquid, fluorine-based solvent, oil (hydrocarbon oil, silicone oil, etc.), and the like, and preferably at least one selected from water and ionic liquid. The liquid substance may be a hydrophilic liquid substance or a hydrophobic liquid substance. Examples of hydrophilic liquid substances include water and hydrophilic ionic liquid. Examples of hydrophobic liquid substances include hydrophobic ionic liquid, fluorine-based solvent, and oil. The liquid substance may be composed of only one type of liquid substance, or may be a mixture of two or more types of liquid substances. The liquid substance may contain an additive. In this embodiment, all or a portion of the solvent contained in the coating composition may remain and serve as the liquid substance contained in the coating film.

[0084] Ionic liquids are also called ionic liquids or room-temperature molten salts, and are salts with ionic conductivity and a low melting point. Many ionic liquids have a relatively low melting point, which is obtained by combining an organic onium ion as the cation with an organic or inorganic anion as the anion. The melting point of an ionic liquid is usually 100°C or less, preferably room temperature (25°C) or less. The melting point of an ionic liquid can be measured using a differential scanning calorimeter (DSC) or the like. Any known ionic liquid can be used as the ionic liquid without any restrictions.

[0085] In the member of this embodiment, the liquid substance contained in the coating film preferably maintains a liquid state even at temperatures below the freezing point (preferably −10°C or lower, more preferably −20°C or lower, and even more preferably −30°C or lower). Whether the liquid substance is in a liquid state can be confirmed by differential scanning calorimetry. If confirmation by differential scanning calorimetry is not possible, it can be confirmed by an indentation hardness test.

[0086] The member of this embodiment can reduce the difference between the icing stress at -8°C and that at -18°C, and from the viewpoint of being excellent in the effect of suppressing ice nucleation, frost formation, and snow and ice accumulation at around -18°C, the ratio of the liquid substance to 100 parts by mass of the total of the graft polymer compound (A) and the crosslinkable polymer compound (B) contained in the coating film at -18°C is preferably 50 parts by mass or more, more preferably 70 parts by mass or more, even more preferably 80 parts by mass or more, and particularly preferably 90 parts by mass or more. This ratio can be adjusted by, for example, combining the graft chains constituting the graft polymer compound (A) with the liquid substance. Furthermore, this ratio can be measured using an atomic force microscope, an ellipsometry method, or the like.

[0087] Furthermore, in the member of this embodiment, the thickness of the coating film in a dry state formed by the coating composition is preferably 10 nm or more, more preferably 50 nm or more, even more preferably 100 nm or more, and particularly preferably 1000 nm or more, from the viewpoint of achieving a superior effect of suppressing ice nucleation, frost formation, and snow and ice accumulation. There is no particular upper limit, but the thickness can be 10 μm or less, or 100 μm or less. The thickness of the coating film formed by the coating composition can be measured by an ellipsometry method or the like. Furthermore, the thickness of the coating film may be a value measured at −18° C.

[0088] The member of this embodiment has an icing stress at −18° C. of 150 kPa or less, preferably 120 kPa or less, more preferably 100 kPa or less, even more preferably 80 kPa or less, still more preferably 65 kPa or less, particularly preferably 50 kPa or less, particularly preferably 35 kPa or less, and most preferably 20 kPa or less. The icing stress at −18° C. can be measured by the method described in the examples below.

[0089] The above-mentioned ice adhesion stress at −18° C. can be adjusted by the type of graft polymer compound (A), the type of crosslinkable polymer compound (B), the presence or absence and type of liquid substance, the surface occupancy of the polymer chains of the graft polymer compound (A), etc.

[0090] The ice adhesion stress of the member of this embodiment at -8°C is preferably 10 to 50 kPa, more preferably 10 to 30 kPa, and even more preferably 0 to 20 kPa. When the ice adhesion stress at -8°C is within the above range, an excellent snow and ice adhesion suppression effect can be obtained over a wide temperature range from 0°C to -18°C. The ice adhesion stress at -8°C can be measured by the method described in the Examples below. The ice adhesion stress at -8°C can be adjusted by the type of graft polymer compound (A), the type of crosslinkable polymer compound (B), the presence or absence and type of liquid substance, the surface occupancy of the polymer chains of the graft polymer compound (A), etc.

[0091] The difference between the icing stress of the member of this embodiment at -18°C and that at -8°C is preferably 100 kPa or less, more preferably 90 kPa or less, even more preferably 80 kPa or less, even more preferably 50 kPa or less, even more preferably 30 kPa or less, and particularly preferably 10 kPa or less. When the difference is within the above range, an excellent snow and ice accumulation suppression effect can be obtained over a wide range of temperatures from 0°C to -18°C. For the member of this embodiment, it is preferable that the icing stress at -18°C is higher than the icing stress at -8°C. Note that the difference between the icing stress at -18°C and that at -8°C refers to the absolute value of the difference.

[0092] In this embodiment, the contact angle of the component surface with water at 25°C is preferably 10° or more, more preferably 20° or more, even more preferably 45° or more, even more preferably 48° or more, and particularly preferably 48 to 80°. A contact angle within the above range achieves better ice nucleation suppression, frost formation suppression, and snow and ice accumulation suppression. The value of the contact angle of the component surface with water is determined by dropping 2 μL of water onto the component surface and measuring the contact angle of water on the component surface 20 seconds after the drop has settled.

[0093] The present invention will be specifically described below based on examples, but the present invention is not limited to these examples.

[0094] Example 1 Preparation of Graft Polymer Compound (A-1) A 2.62 M toluene solution of 2-bromoisobutyryloxyethyl methacrylate (BIEM) was subjected to reversible addition-fragmentation chain transfer polymerization in the presence of 30 mM cumyldithiobenzoate (CTA) and 6 mM azobisisobutyronitrile (AIBN) at 60°C for 18 hours to obtain a main chain polymer (PolyBIEM) having an atom transfer radical polymerization (ATRP) initiation point. The obtained main chain polymer (PolyBIEM) was characterized by GPC, and the number average molecular weight (Mn) calculated as polymethyl methacrylate was 1.6 x 10 ４ The molecular weight distribution (dispersity index PDI) was 1.12. GPC measurement was performed using a Shodex GPC101 (manufactured by Resonac) as a GPC measurement device, Shodex LF-804 (manufactured by Resonac) and Shodex KF-06L (manufactured by Resonac) as columns, with THF as the developing solvent flowing at a flow rate of 0.8 mL / min. The oven temperature was set to 40°C.

[0095] Subsequently, the main chain polymer (PolyBIEM) obtained above was subjected to atom transfer radical polymerization (ATRP) using poly(ethylene glycol) methacrylate (PEGMA-OH, number average molecular weight (Mn): 500) and a copper catalyst to obtain a graft polymer compound (A-1). In this case, the ratio of ethyl 2-bromoisobutyrate (EBIB, initiator): main chain polymer (PolyBIEM): poly(ethylene glycol) methacrylate (PEGMA-OH): CuBr: CuBr ２ The molar ratio of diN-bip to 4,4'-dinonyl-2,2'-bipyridine (diN-bip) was 0.1:1:100:0.8:0.2:2, and anisole was used as a solvent in an amount four times the mass of poly(ethylene glycol) methacrylate (PEGMA-OH). The reaction conditions were 65°C and 0.5 hours. The resulting graft polymer compound (A-1) was characterized by GPC, and the number average molecular weight (Mn) calculated as polymethyl methacrylate was 9.2 x 10 ４The molecular weight distribution (dispersity index PDI) was 2.0. GPC measurement was performed using a Shodex GPC101 (manufactured by Resonac) as a GPC measuring device, Shodex LF-804 (manufactured by Resonac) and Shodex KF-06L (manufactured by Resonac) as columns, with DMF / LiCl as a developing solvent flowing at a flow rate of 0.8 mL / min. The oven temperature was set to 40°C. The surface occupancy of the graft chains of the obtained graft polymer compound (A-1) was measured by the above-mentioned method, and the surface occupancy was found to be 0.15. The obtained graft polymer compound (A-1) was purified by dialysis in methanol as a poor solvent, dried overnight under vacuum at room temperature, and then stored.

[0096] (Preparation of Crosslinkable Polymer Compound (B-1)) A blocked isocyanate group-containing methacrylate having a reactive double bond (2-[(3,5-dimethylpyrazolyl)carbonylamino]ethyl methacrylate, trade name "Karenz MOI-BP", manufactured by Resonac Corporation) and poly(ethylene glycol) methyl ether methacrylate (PEGMA-OMe, number average molecular weight (Mn): 500) were used in a molar ratio of blocked isocyanate compound having a reactive double bond:poly(ethylene glycol) methyl ether methacrylate (PEGMA-OMe) = 5.25:99.75 (= 5:95), and a copper catalyst was added to these compounds to perform atom transfer radical polymerization (ATRP) at 65°C for 48 hours, to obtain a crosslinkable polymer compound (B-1). In this case, ethyl 2-bromoisobutyrate (EBIB, initiator): poly(ethylene glycol) methyl ether methacrylate (PEGMA-OMe): blocked isocyanate group-containing methacrylate (MOI-BP): CuBr: CuBr ２The molar ratio of diN-bip to 4,4'-dinonyl-2,2'-bipyridine (diN-bip) was 1.1:99.75:5.25:0.8:0.2:2, and anisole was used as a solvent in an amount twice the mass of poly(ethylene glycol) methyl ether methacrylate (PEGMA-OMe). The resulting crosslinkable polymer compound (B-1) was characterized by GPC, and the number average molecular weight (Mn) calculated as polymethyl methacrylate was 3.2 × 10 ４ The molecular weight distribution (dispersity index PDI) was 1.3. GPC measurement was performed using a Shodex GPC101 (manufactured by Resonac) as a GPC measurement device, Shodex LF-804 (manufactured by Resonac) and Shodex KF-06L (manufactured by Resonac) as columns, with DMF / LiCl as the developing solvent flowing at a flow rate of 0.8 mL / min. The oven temperature was set to 40°C. The polymerization conversion of each monomer was １ The content of poly(ethylene glycol) methyl ether methacrylate (PEGMA-OMe) was 88.4%, and the content of blocked isocyanate group-containing methacrylate (MOI-BP) was 91.2% as determined by H-NMR measurement. The resulting crosslinkable polymer compound (B-1) was purified by reprecipitation using acetone / hexane=3 / 10 (vol / vol), dried overnight under vacuum at room temperature, and then stored.

[0097] (Preparation of Coating Composition) Using the graft polymer compound (A-1) and crosslinkable polymer compound (B-1) obtained above, a coating composition containing the graft polymer compound (A-1):crosslinkable polymer compound (B-1) in a ratio of 99.9:0.1 (mass ratio) was prepared. The coating composition used propylene glycol monomethyl ether acetate (PGMAc) as the solvent, and dibutyltin dilaurate as the catalyst in a ratio of 1 part by mass per 100 parts by mass of the total of the graft polymer compound (A-1) and the crosslinkable polymer compound (B-1). The coating composition was prepared so that the total content of the graft polymer compound (A-1) and the crosslinkable polymer compound (B-1) was 2% by mass.

[0098] (Preparation of Member Having Coating Film) A silicon substrate (Si-wafer) was prepared, and 3-(2-aminoethylaminopropyl)trimethoxysilane was reacted on the silicon substrate under basic conditions, thereby introducing residues derived from 3-(2-aminoethylaminopropyl)trimethoxysilane into the silicon substrate. The coating composition obtained above was then spin-coated onto the silicon substrate with the residues derived from 3-(2-aminoethylaminopropyl)trimethoxysilane introduced using a spin coater, and then heated at 120°C for 1 hour to promote the crosslinking reaction between the graft polymer compound (A-1) and the crosslinkable polymer compound (B-1), forming a coating film on the silicon substrate, thereby preparing a member having a coating film. The film thickness of the formed coating film was measured at room temperature using a spectroscopic ellipsometry method (MASS-105, manufactured by Five Labs) and was found to be 105 nm. For optical constants, etc., a file created using each test specimen prepared according to the manufacturer's specified method was used.

[0099] (Icing Stress Measurement) The member with the coating film obtained above was then placed on a microscope-equipped stretching stage with cooling function (manufactured by Japan High-Tech Co., Ltd.) and subjected to icing stress measurement. 60 μL of pure water was poured into the inside of an aluminum cylinder (inner diameter 6 mm) with silicone grease applied to the edges to wet the coating film. This was then cooled to -20°C at a rate of 5°C / min and held for 30 minutes to create an icicle from the excess water that did not contribute to wetting the coating film. The set temperature of the stage was then raised to the measurement temperature (-18°C or -8°C) at a rate of 5°C / min and held for 30 minutes, after which the test was performed. The L-shaped jig attached to the stage was set to press against the aluminum cylinder as the stretching stage moved, and the icing stress was calculated from the load applied to the load cell of the stretching stage when the icicle peeled off (Figure 1). The stage movement speed was 10 mm / min. The icing stress was evaluated according to the following criteria. The results are shown in Table 1. Very good: Ice stress at -18°C is 100kPa or less Good: Ice stress at -18°C is more than 100kPa and less than 150kPa Poor: Ice stress at -18°C is more than 150kPa

[0100] Examples 2 to 5 Coating compositions were prepared in the same manner as in Example 1, except that the mass ratio of the graft polymer compound (A-1) to the crosslinkable polymer compound (B-1) was changed to 99:1 (Example 2), 90:10 (Example 3), 75:25 (Example 4), and 60:40 (Example 5) when preparing the coating compositions. Next, using the resulting coating compositions, members provided with coating films were formed in the same manner as in Example 1, and the icing stress was measured in the same manner as in Example 1. The measurement results are shown in Table 1. The thicknesses of the coating films in Examples 2 to 5 were 100 nm (Example 2), 120 nm (Example 3), 105 nm (Example 4), and 107 nm (Example 5), respectively.

[0101] Example 6 Preparation of Graft Polymer Compound (A-2) Atom transfer radical polymerization (ATRP) was carried out on the main chain polymer (PolyBIEM) obtained in the same manner as in Example 1 using poly(ethylene glycol) methyl ether methacrylate (PEGMA-OMe, number average molecular weight (Mn): 500) and a copper catalyst. The polymerization conditions were as follows: ethyl 2-bromoisobutyrate (EBIB, initiator): main chain polymer (PolyBIEM): poly(ethylene glycol) methyl ether methacrylate (PEGMA-OMe): CuBr: CuBr ２ The molar ratio of diN-bip to 4,4'-dinonyl-2,2'-bipyridine (diN-bip) was 0.1:1:105:0.8:0.2:2, and anisole was used as a solvent in an amount twice the mass of poly(ethylene glycol) methyl ether methacrylate (PEGMA-OMe). After stirring at 65°C for 1 hour and 30 minutes, １ H-NMR measurement was carried out to identify the amount of remaining poly(ethylene glycol) methyl ether methacrylate (PEGMA-OMe), and 10 mol % of 3-(trimethoxysilyl)propyl methacrylate (MOPS) was added to the remaining poly(ethylene glycol) methyl ether methacrylate (PEGMA-OMe), followed by stirring at 65°C for 30 minutes to obtain a graft polymer compound (A-2). The obtained graft polymer compound (A-2) was characterized by GPC, and the number average molecular weight (Mn) in terms of polymethyl methacrylate was 1.4 × 10 ５The molecular weight distribution (dispersity index PDI) was 1.1. GPC measurement was performed using a Shodex GPC101 (manufactured by Resonac) as a GPC measurement device, Shodex LF-804 (manufactured by Resonac) and Shodex KF-06L (manufactured by Resonac) as columns, and by flowing DMF / LiCl as a developing solvent at a flow rate of 0.8 mL / min. The oven temperature was set to 40°C. The surface occupancy of the graft chains of the obtained graft polymer compound (A-2) was measured by the above-mentioned method, and the surface occupancy was found to be 0.30. The obtained graft polymer compound (A-2) was purified by reprecipitation using hexane / acetone = 10 / 3 (Vol / Vol), dried overnight under vacuum at room temperature, and then stored.

[0102] (Preparation of Crosslinkable Polymer Compound (B-2)) Poly(ethylene glycol) methyl ether methacrylate (PEGMA-OMe, number average molecular weight (Mn): 500), 3-(trimethoxysilyl)propyl methacrylate (MOPS), and 2,2'-azobisisobutyronitrile (AIBN) as a polymerization initiator were used in a molar ratio of poly(ethylene glycol) methyl ether methacrylate (PEGMA-OMe):3-(trimethoxysilyl)propyl methacrylate (MOPS):2,2'-azobisisobutyronitrile (AIBN) = 125:1.25:1 to perform free radical polymerization to obtain crosslinkable polymer compound (B-2). In this case, anisole was used as the solvent in an amount equal to the mass of poly(ethylene glycol) methyl ether methacrylate (PEGMA-OMe), and the polymerization was carried out at 60°C for 3 hours. The resulting crosslinkable polymer compound (B-2) was characterized by GPC, and the number average molecular weight (Mn) calculated as polymethyl methacrylate was 2,300,000, and the molecular weight distribution (dispersity index PDI) was 3.0. The GPC measurement was performed using a Shodex GPC101 (manufactured by Resonac) as the GPC measuring device, Shodex LF-804 (manufactured by Resonac) and Shodex KF-06L (manufactured by Resonac) as the columns, with DMF / LiCl as the developing solvent flowing at a flow rate of 0.8 mL / min. The oven temperature was set to 40°C. The resulting crosslinkable polymer compound (B-2) was purified by reprecipitation using hexane / acetone = 10 / 3 (vol / vol), dried overnight under vacuum at room temperature, and then stored. The purified polymer １ The amount of MOPS introduced was found to be about 1 mol % by H-NMR measurement.

[0103] (Preparation of Coating Composition, Preparation of Member Having Coating Film) Using the graft polymer compound (A-2) obtained above and the crosslinkable polymer compound (B-2) obtained above, a coating composition containing the graft polymer compound (A-2):crosslinkable polymer compound (B-2) in a ratio of 92:8 (mass ratio) was prepared. The coating composition used propylene glycol monomethyl ether acetate (PGMAc) as the solvent, and 0.1 N diluted hydrochloric acid as the catalyst in a ratio of 1 part by mass per 100 parts by mass of the total of the graft polymer compound (A-2) and the crosslinkable polymer compound (B-2). The coating composition was also prepared so that the total content of the graft polymer compound (A-2) and the crosslinkable polymer compound (B-2) was 2% by mass. Next, a member having a coating film was formed using the obtained coating composition in the same manner as in Example 1, and the icing stress was measured in the same manner as in Example 1. The measurement results are shown in Table 1. The thickness of the coating film in Example 6 was 98 nm.

[0104] Comparative Example 1 A coating composition was prepared using the graft polymer compound (A-2) obtained in Example 6. The coating composition used propylene glycol monomethyl ether acetate (PGMAc) as the solvent and 0.1 N diluted hydrochloric acid as the catalyst in a proportion of 1 part by mass per 100 parts by mass of the graft polymer compound (A-2). The content of the graft polymer compound (A-2) in the coating composition was adjusted to 2 mass%. Next, a member having a coating film was formed using the obtained coating composition in the same manner as in Example 1, and the icing stress at −18°C was measured in the same manner as in Example 1. Because the measurement result of the icing stress at −18°C exceeded 150 kPa, the measurement of the icing stress at −8°C was not performed. The measurement results are shown in Table 1. The thickness of the coating film in Comparative Example 1 was 100 nm.

[0105] Comparative Example 2 A coating composition was prepared in the same manner as in Example 6, except that tetraethoxysilane was used instead of the crosslinkable polymer compound (B-2). Next, a member provided with a coating film was formed using the obtained coating composition in the same manner as in Example 1, and the icing stress was measured in the same manner as in Comparative Example 1. The measurement results are shown in Table 1. The thickness of the coating film in Comparative Example 2 was 100 nm.

[0106] Comparative Example 3 (Preparation of Graft Polymer Compound (A-3)) Atom transfer radical polymerization (ATRP) was carried out on the main chain polymer (PolyBIEM) obtained in the same manner as in Example 1 using poly(ethylene glycol) methyl ether methacrylate (PEGMA-OMe, number average molecular weight (Mn): 500) and a copper catalyst to obtain a graft polymer compound (A-3). In this case, the ratio of ethyl 2-bromoisobutyrate (EBIB, initiator): main chain polymer (PolyBIEM): poly(ethylene glycol) methyl ether methacrylate (PEGMA-OMe): CuBr: CuBr ２ The molar ratio of diN-bip to 4,4'-dinonyl-2,2'-bipyridine (diN-bip) was 0.1:1:105:0.8:0.2:2, and anisole was used as a solvent in an amount twice the mass of poly(ethylene glycol) methyl ether methacrylate (PEGMA-OMe). The reaction conditions were 65°C and 2 hours. The resulting graft polymer compound (A-3) was characterized by GPC, and the number average molecular weight (Mn) calculated as polymethyl methacrylate was 1.3 x 10 ５The molecular weight distribution (dispersity index PDI) was 1.1. GPC measurement was performed using a Shodex GPC101 (manufactured by Resonac) as a GPC measuring device, Shodex LF-804 (manufactured by Resonac) and Shodex KF-06L (manufactured by Resonac) as columns, and by flowing DMF / LiCl as a developing solvent at a flow rate of 0.8 mL / min. The oven temperature was set to 40°C. The surface occupancy of the graft chains of the obtained graft polymer compound (A-3) was measured by the above-mentioned method, and the surface occupancy was found to be 0.30. The obtained graft polymer compound (A-3) was purified by reprecipitation using hexane / acetone = 10 / 3 (Vol / Vol), dried overnight under vacuum at room temperature, and then stored.

[0107] (Preparation of Coating Composition, Preparation of Member Having Coating Film) A coating composition was prepared using the graft polymer compound (A-3) obtained above. The coating composition used anisole as the solvent and tetrakis(dimethylamino)ethylene (a catalyst for crosslinking bromine atoms derived from 2-bromoisobutyryloxyethyl methacrylate (BIEM) contained in the graft polymer compound (A-3)) as the catalyst in a proportion of 1 part by mass per 100 parts by mass of the graft polymer compound (A-3). The content of the graft polymer compound (A-3) in the coating composition was adjusted to 2% by mass. A silicon substrate (Si-wafer) was prepared, and 3-(trimethoxysilyl)propyl-2-bromo-2-methylpropanoate was reacted on the silicon substrate under basic conditions, thereby introducing residues derived from 3-(trimethoxysilyl)propyl-2-bromo-2-methylpropanoate into the silicon substrate. The coating composition obtained above was spin-coated using a spin coater onto a silicon substrate having a residue derived from 3-(trimethoxysilyl)propyl-2-bromo-2-methylpropanoate introduced therein, and then heated at 120°C for 1 hour to promote a crosslinking reaction between the graft polymer compound (A-3) molecules, thereby forming a coating film on the silicon substrate, and a member having the coating film was prepared. Next, a member having the coating film was formed using the obtained coating composition in the same manner as in Example 1, and the icing stress was measured in the same manner as in Comparative Example 1. The measurement results are shown in Table 1. The thickness of the coating film in Comparative Example 3 was 105 nm.

[0108] Comparative Example 4 A coating composition was prepared in the same manner as in Example 1, except that the ratio of the graft polymer compound (A-1) to the crosslinkable polymer compound (B-1) was changed to a mass ratio of 50:50 (graft polymer compound (A-1):crosslinkable polymer compound (B-1)) when preparing the coating composition. Next, a member provided with a coating film was formed using the obtained coating composition in the same manner as in Example 1, and the icing stress was measured in the same manner as in Comparative Example 1. The measurement results are shown in Table 1. The thickness of the coating film in Comparative Example 4 was 93 nm.

[0109] Comparative Example 5 A coating composition was prepared in the same manner as in Example 1, except that Trixene® Aqua BI 7982 (manufactured by Lanxess AG, low-molecular-weight isocyanate compound, molecular weight: 764) was used instead of the crosslinkable polymer compound (B-1), and the mass ratio of "graft polymer compound (A-1):Trixene® Aqua BI 7982 (low-molecular-weight isocyanate compound)" was set to 90:10. Next, a member provided with a coating film was formed using the obtained coating composition in the same manner as in Example 1, and the icing stress was measured in the same manner as in Comparative Example 1. The measurement results are shown in Table 1. The thickness of the coating film in Comparative Example 5 was 93 nm.

[0110] Examples 7 to 11 (Preparation of Graft Polymer Compound (A-4)) Graft polymer compound (A-3) obtained in the same manner as in Comparative Example 3 was subjected to atom transfer radical polymerization (ATRP) using a blocked isocyanate group-containing methacrylate having a reactive double bond (2-[(3,5-dimethylpyrazolyl)carbonylamino]ethyl methacrylate, trade name "Karenz MOI-BP", manufactured by Resonac Corporation) and a copper catalyst, to obtain graft polymer compound (A-4). In this case, the molar ratio of the reaction initiation point of the graft polymer compound (A-3):blocked isocyanate group-containing methacrylate:CuBr:CuBr2:4,4'-dinonyl-2,2'-bipyridine (diN-bip) was 1:500:0.8:0.2:2.2, anisole was used as the solvent in an amount equal to the mass of the blocked isocyanate group-containing methacrylate, and the reaction conditions were 60°C and 15 minutes. Characterization of the resulting graft polymer compound (A-4) by 1H-NMR confirmed that an average of 1.3 units of blocked isocyanate group-containing methacrylate had been introduced at each graft terminal. Furthermore, the surface occupancy of the graft chains of the graft polymer compound (A-4) obtained by the above-described method can be considered to be equivalent to that of the graft polymer compound (A-3) based on the calculation method. The obtained graft polymer compound (A-4) was washed with a 2 wt % aqueous solution of EDTA (ethylenediaminetetraacetic acid) to remove the copper catalyst, and then purified by reprecipitation using hexane / acetone = 10 / 3 (Vol / Vol), dried overnight under vacuum at room temperature, and then stored.

[0111] (Preparation of Coating Composition, Preparation of Member Having Coating Film) The graft polymer compound (A-4) obtained above and cellulose nanofiber (trade name "Celembea TC-01A", manufactured by Nippon Paper Industries Co., Ltd., Mn = 17,600, Mw = 16,3600) as the crosslinkable polymer compound (B-3) were used, and the graft polymer compound (A-4) and the crosslinkable polymer compound (B-3) (Celembea TC-01A) were mixed to obtain the solid content mass ratios shown in Table 2 to prepare the coating compositions of Examples 7 to 11. The coating compositions used pure water as the solvent, and DABCO (1,4-Diazabicyclo[2.2.2]octane) as the catalyst in a proportion of 1 part by mass per 100 parts by mass of the total of the graft polymer compound (A-4) and the crosslinkable polymer compound (B-3) (Celembea TC-01A). The coating composition was prepared so that the total content of the graft polymer compound (A-4) and the crosslinkable polymer compound (B-3) (Celembia TC-01A) in the coating composition was 1.5% by mass.

[0112] (Preparation of Member Having Coating Film) A silicon substrate (Si-wafer) was prepared, and 3-(2-aminoethylaminopropyl)trimethoxysilane was reacted on the silicon substrate under basic conditions, thereby introducing residues derived from 3-(2-aminoethylaminopropyl)trimethoxysilane into the silicon substrate. The coating compositions of Examples 7 to 11 were then spin-coated onto the silicon substrate with residues derived from 3-(2-aminoethylaminopropyl)trimethoxysilane using a spin coater, and the resulting silicon substrate was then heated at 70°C for 18 hours under reduced pressure conditions to promote a crosslinking reaction between the graft polymer compound (A-4) and the crosslinkable polymer compound (Celembia TC-01A), forming a coating film on the silicon substrate and preparing a member having a coating film. The thickness of the formed coating film was measured at room temperature using a spectroscopic ellipsometry method (MASS-105, manufactured by Five Labs) and found to be 220 nm. For optical constants, etc., files created using each test specimen were used according to the manufacturer's specified method.

[0113]

[0114]

[0115] As shown in Table 1, members having a coating film formed using a coating composition containing a graft polymer compound (A) having a structural unit represented by general formula (1) and a crosslinkable functional group (a) and a crosslinkable polymer compound (B) having two or more reactive functional groups (b) different from the crosslinkable functional group (a), wherein the content of the crosslinkable polymer compound (B) is 0.1 mass % or more and less than 50 mass % relative to the total of 100 mass % of the graft polymer compound (A) and the crosslinkable polymer compound (B), had low icing stress at -18°C and were able to effectively suppress ice nucleation, frost formation, and snow and ice accumulation (Examples 1 to 11). When the crosslinkable polymer compound (B) is a copolymer of a monomer having a reactive functional group (b) and a monomer copolymerizable with such a monomer, and the crosslinkable functional group (a) and the reactive functional group (b) are different groups, the icing stress at -18 ° C is extremely low, and ice nucleation, frost formation, and snow and ice accumulation can be suppressed very effectively (Examples 1 to 5). Furthermore, when the crosslinkable polymer compound (B) is a copolymer of a monomer having a reactive functional group (b) and a monomer copolymerizable with such a monomer, and a graft-type polymer compound (A) and a crosslinkable polymer compound (B) having the same crosslinkable functional group are used, the icing stress at -18 ° C is also low, and ice nucleation, frost formation, and snow and ice accumulation can be effectively suppressed (Example 6). Furthermore, when the crosslinkable polymer compound (B) is cellulose nanofiber, the icing stress at -18 ° C is also low, and ice nucleation, frost formation, and snow and ice accumulation can be effectively suppressed (Examples 7 to 11).

[0116] On the other hand, when the crosslinkable polymer compound (B) was not contained (Comparative Examples 1 and 3), when a compound having a reactive functional group (b) but which was not a polymer compound was used (Comparative Examples 2 and 5), and when the content of the crosslinkable polymer compound (B) was too high (Comparative Example 4), the icing stress at −18° C. was high, and the effect of suppressing ice nucleation, frost formation, and snow and ice accumulation could not be expected.

Claims

1. A component for suppressing ice nucleation, frost formation, or snow and ice accumulation, having a coating film obtained by applying a coating composition containing a solvent and a polymer, The polymer comprises a graft-type polymer compound (A) having a structural unit represented by the following general formula (1) and a crosslinkable functional group (a), and a crosslinkable polymer compound (B) having two or more reactive functional groups (b) that crosslink with the crosslinkable functional group (a). The content of the crosslinkable polymer compound (B) in the total of 100% by mass of the graft-type polymer compound (A) and the crosslinkable polymer compound (B) is 0.1% by mass or more and less than 50% by mass. A component whose ice formation stress at -18°C is 150 kPa or less. 【Transformation 7】 (In the above general formula (1), R １ represents a hydrogen atom or a methyl group, X represents O or NH, and R represents a hydrogen atom or a methyl group. ２ R represents any organic group. ３ and R ４ Each of these independently represents a hydrogen atom, an alkyl group, an aryl group, or an acyl group, and R ３ and R ４ The carbon atoms to which the molecule is bonded are tertiary or quaternary carbon atoms, n represents an arbitrary number of repeats, and Polymer represents a graft chain containing constituent units derived from at least one graft monomer selected from the group consisting of (meth)acrylic acid monomers, (meth)acrylamide monomers, aromatic vinyl monomers, and (meth)acrylonitrile.

2. The member according to claim 1, wherein the difference between the ice formation stress at -18°C and the ice formation stress at -8°C is 100 kPa or less.

3. The member according to claim 1 or 2, wherein the crosslinkable functional group (a) and the reactive functional group (b) are different groups from each other.

4. The member according to claim 1 or 2, wherein the surface occupancy rate of the graft chains of the graft-type polymer compound (A) is 0.05 or more and less than 0.

75.

5. The member according to claim 1 or 2, wherein the number average molecular weight (Mn) of the crosslinkable polymer compound (B) is 5,000 to 3,000,000.

6. The member according to claim 1 or 2, wherein the crosslinkable functional group (a) and the reactive functional group (b) are, each, at least one functional group selected from the group consisting of a hydroxyl group, an isocyanate group, a blocked isocyanate group, and an alkoxysilyl group.

7. The member according to claim 1 or 2, wherein the number average molecular weight (Mn) of the graft-type polymer compound (A) is 10,000 to 1,000,000.

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