JP7701199B2 - Fluorine-containing surface modifier composition - Google Patents

Description

The present invention relates to a fluorine-containing surface modifier composition.

Fluorine-containing compounds exhibit characteristic functions such as heat resistance, chemical resistance, water and oil repellency, low friction, and peelability due to the properties of the carbon-fluorine bond. Taking advantage of these properties, fluorine-containing compounds are used as surface modifiers that impart functionality to various substrates, such as water and oil repellents, antifouling agents, release agents, and moisture-proof coating agents.

Up to now, fluorine-containing polymers containing (meth)acrylic acid esters having fluoroalkyl groups as polymerization units have been used as raw materials for fluorine-containing surface modifiers. In particular, it is known that fluorine-containing polymers containing fluorine-containing (meth)acrylic acid esters having perfluoroalkyl groups with 8 or more carbon atoms as polymerization units have excellent dynamic water repellency and can effectively slide off water droplets attached to the surface (see, for example, Non-Patent Document 1). However, compounds having perfluoroalkyl groups with 8 or more carbon atoms are problematic in terms of the possibility of adverse effects on the environment and living organisms, such as bioaccumulation.
For this reason, replacement with fluorine-containing polymers containing, as polymerization units, fluorine-containing (meth)acrylic esters having short-chain perfluoroalkyl groups with 6 or less carbon atoms, which are considered to have low bioaccumulation, has been studied. However, it is known that surface modifiers made of fluorine-containing polymers having short-chain perfluoroalkyl groups have reduced functions such as water and oil repellency, compared with fluorine-containing polymers having perfluoroalkyl groups with 8 or more carbon atoms.

Patent Document 1 discloses a surface modifier containing a fluorine-containing (meth)acrylate polymer having an unsaturated bond in the side chain. However, because a non-fluorine-based organic solvent is used as the solvent, there are problems such as flammability and corrosion to resin substrates, and further improvements are required.

International Publication No. 2017/119371

Macromolecules, 2010, Vol. 43, 454-460

The object of the present invention is to provide a fluorine-containing surface modifier composition that has excellent water and oil repellency, low flammability, and low corrosion resistance to resins, by using a fluorine-containing polymer composed of perfluoroalkyl groups having 6 or less carbon atoms, which are considered to have low bioaccumulation.

As a result of intensive research conducted by the present inventors to solve the above problems, they discovered that a composition containing a fluorine-containing polymer consisting of structural units based on a fluorine-containing (meth)acrylic acid ester having an unsaturated bond in the side chain and a fluorine-based solvent that is less flammable and less corrosive to resins exhibits excellent water and oil repellency, and thus completed the present invention.

（式（１）中、Ｒｆ^１は炭素数１～６のパーフルオロアルキル基であり、Ｒｆ^２は炭素数１～６のパーフルオロアルキレン基であり、ｎは１～４の整数であり、Ｒは水素原子またはメチル基である。）
［２］ 含フッ素重合体は、下記一般式（２）で示される含フッ素（メタ）アクリル酸エステルが重合されてなることを特徴とする、［１］に記載の含フッ素表面改質剤組成物。

（式（１）中、Ｒｆ^１は炭素数１～６のパーフルオロアルキル基であり、Ｒｆ^２は炭素数１～６のパーフルオロアルキレン基であり、ｎは１～４の整数であり、Ｒは水素原子またはメチル基である。）
なお、本発明に係る含フッ素表面改質剤組成物は、含フッ素（メタ）アクリル酸エステルが重合されてなる含フッ素重合体とフッ素系溶媒とを含むが、含フッ素重合体をその構造から規定するよりも原料となるモノマーを規定した上で重合されるとすることで把握しやすく実際的である。以下の［３］においても同様である。
［３］ 含フッ素重合体が、単量体Ａ及び単量体Ａと共重合する単量体Ｂから構成されており、単量体Ａと単量体Ｂとの重量比（Ａ）／（Ｂ）が１：９９～９９．９：０．１の重量比で共重合されてなる、［１］に記載の含フッ素表面改質剤組成物。
［４］ 単量体Ｂが、（メタ）アクリル酸、（メタ）アクリル酸のエステル類、スチレン類、脂肪酸ビニルエステル類、ハロゲン化ビニル、ハロゲン化ビニリデン類、脂肪酸アリルエステル類及びアクリルアミド類からなる群より選ばれる一種以上である、［３］に記載の含フッ素表面改質剤組成物。
［５］ フッ素系溶媒が、ハイドロフルオロエーテル、ハイドロフルオロカーボン、パーフルオロカーボン、ハイドロクロロフルオロカーボン及びクロロフルオロカーボンからなる群より選ばれる少なくとも一つである、［１］～［４］のいずれかに記載の含フッ素表面改質剤組成物。
［６］ 含フッ素重合体とフッ素系溶媒の総量、すなわち合計重量に対して、含フッ素重合体を０．０１重量％～５０重量％含む、［１］～［５］のいずれかに記載の含フッ素表面改質剤組成物。 That is, the present invention relates to the following.
[1] A fluorine-containing surface modifier composition comprising a fluorine-containing polymer having a residue unit represented by the following general formula (1) and a fluorine-containing solvent:

(In formula (1), Rf ¹ is a perfluoroalkyl group having 1 to 6 carbon atoms, Rf ² is a perfluoroalkylene group having 1 to 6 carbon atoms, n is an integer of 1 to 4, and R is a hydrogen atom or a methyl group.)
[2] The fluorine-containing surface modifier composition according to [1], characterized in that the fluorine-containing polymer is obtained by polymerizing a fluorine-containing (meth)acrylic acid ester represented by the following general formula (2):

(In formula (1), Rf ¹ is a perfluoroalkyl group having 1 to 6 carbon atoms, Rf ² is a perfluoroalkylene group having 1 to 6 carbon atoms, n is an integer of 1 to 4, and R is a hydrogen atom or a methyl group.)
The fluorine-containing surface modifier composition according to the present invention contains a fluorine-containing polymer obtained by polymerizing a fluorine-containing (meth)acrylic ester and a fluorine-based solvent, but it is easier to understand and more practical to define the fluorine-containing polymer by polymerizing the monomers that are raw materials rather than by defining the fluorine-containing polymer from its structure. The same applies to the following [3].
[3] The fluorine-containing surface modifier composition according to [1], wherein the fluorine-containing polymer is composed of a monomer A and a monomer B which is copolymerizable with the monomer A, and the monomer A and the monomer B are copolymerized in a weight ratio (A)/(B) of 1:99 to 99.9:0.1.
[4] The fluorine-containing surface modifier composition according to [3], wherein the monomer B is at least one selected from the group consisting of (meth)acrylic acid, esters of (meth)acrylic acid, styrenes, fatty acid vinyl esters, vinyl halides, vinylidene halides, fatty acid allyl esters and acrylamides.
[5] The fluorine-containing surface modifier composition according to any one of [1] to [4], wherein the fluorine-based solvent is at least one selected from the group consisting of hydrofluoroethers, hydrofluorocarbons, perfluorocarbons, hydrochlorofluorocarbons and chlorofluorocarbons.
[6] The fluorine-containing surface modifier composition according to any one of [1] to [5], which contains 0.01% by weight to 50% by weight of the fluorine-containing polymer based on the total amount of the fluorine-containing polymer and the fluorine-based solvent, i.e., the total weight.

The present invention will be described in detail below.
In the fluorine-containing polymer of the present invention having a residue unit represented by general formula (1), Rf ¹ is a perfluoroalkyl group having 1 to 6 carbon atoms. Among them, a linear perfluoroalkyl group having 1 to 6 carbon atoms is preferred, a linear perfluoroalkyl group having 4 to 6 carbon atoms is more preferred, and a linear perfluoroalkyl group having 6 carbon atoms is particularly preferred.
In the fluorine-containing polymer of the present invention having a residue unit represented by general formula (1), ^Rf2 is a perfluoroalkylene group having 1 to 6 carbon atoms. Among them, a linear perfluoroalkylene group having 1 to 6 carbon atoms is preferred, a linear perfluoroalkylene group having 4 to 6 carbon atoms is more preferred, and a linear perfluoroalkylene group having 6 carbon atoms is particularly preferred.
Specific examples of the Rf ¹ -CH=CH-Rf ² - portion in general formula (1) include, but are not limited to, C ₂ F ₅ -CH=CH-C ₄ F ₈ -, C ₂ F ₅ -CH=CH-C ₆ F ₁₂ -, C ₄ F ₉ -CH=CH-C ₄ F ₈ -, C ₄ F ₉ -CH=CH-C ₆ F ₁₂ , C ₆ F ₁₃ -CH=CH-C 4 F ₈ - _, and C ₆ F ₁₃ -CH=CH-C ₆ F ₁₂ -.

In the fluoropolymer of the present invention having a residue unit represented by formula (1), n is an integer of from 1 to 4. Of these, n is preferably from 2 to 3, and particularly preferably 2.
In the fluorine-containing polymer of the present invention having a residue unit represented by formula (1), R is a hydrogen atom or a methyl group.

In one preferred embodiment of the present invention, the fluorine-containing polymer is obtained by polymerizing a fluorine-containing (meth)acrylic ester represented by general formula (2) (hereinafter, when the fluorine-containing (meth)acrylic ester is used to copolymerize with another monomer, this may be referred to as "monomer A"). Here, when the fluorine-containing (meth)acrylic ester represented by general formula (2) is polymerized alone, this may be referred to as homopolymerization. In this embodiment, the polymerization method is not particularly limited, but for example, solution polymerization using a solvent may be performed.

In this embodiment, the solvent used in the solution polymerization is not particularly limited, and specific examples thereof include aromatic hydrocarbon solvents such as benzene, toluene, xylene, ethylbenzene, and tetralin; aliphatic or alicyclic hydrocarbon solvents such as n-hexane, n-heptane, mineral spirits, and cyclohexane; halogen-based solvents such as methyl chloride, methyl bromide, methyl iodide, methylene dichloride, chloroform, carbon tetrachloride, trichloroethylene, perchloroethylene, and orthodichlorobenzene; ester-based or ester ether-based solvents such as ethyl acetate, butyl acetate, methoxybutyl acetate, methyl cellosolve acetate, ethyl cellosolve acetate, and propylene glycol monomethyl ether acetate; ether-based solvents such as diethyl ether, tetrahydrofuran, 1,4-dioxane, methyl cellosolve, ethyl cellosolve, butyl cellosolve, and propylene glycol monomethyl ether; acetone, methyl ethyl ketone, methyl isobutyl ketone, di- Examples of the solvent include ketone-based solvents such as n-butyl ketone and cyclohexanone; alcohol-based solvents such as methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, tert-butanol, 2-ethylhexyl alcohol and benzyl alcohol; amide-based solvents such as N,N-dimethylformamide and N,N-dimethylacetamide; sulfoxide-based solvents such as dimethyl sulfoxide; heterocyclic compound-based solvents such as N-methyl-2-pyrrolidone; trifluoromethylbenzene, 1,3-bis(trifluoromethyl)benzene, 1,4-bis(trifluoromethyl)benzene, 1,1,1,2,2-pentafluoro-3,3-dichloropropane, 1,1,2,2,3-pentafluoro-1,3-dichloropropane, pentafluorobutane, decafluoropentane, perfluorohexane, perfluorocyclohexane, perfluorodecalin, hexafluorobenzene, and fluorine-based solvents such as hydrofluoroethers. These solvents may be used alone or in combination of two or more.
In this embodiment, the amount of the solvent used in the solution polymerization is not particularly limited, but is preferably 1 to 200 times by weight, more preferably 2 to 100 times by weight, based on the amount of the monomer A used in the polymerization reaction.

In this embodiment, the polymerization reaction can be progressed by using, for example, a polymerization initiator. The polymerization initiator is not particularly limited, but examples thereof include azo compounds such as 2,2'-azobisisobutyronitrile, 2,2'-azobis(2-methylbutyronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 1,1'-azobis(1-cyclohexanecarbonitrile), 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), and 2-(carbamoylazo)isobutyronitrile; peroxides such as benzoyl peroxide, di-t-butyl peroxide, diisopropyl peroxydicarbonate, t-butyl peroxypivalate, and lauryl peroxide; and persulfates such as potassium persulfate and ammonium persulfate. These polymerization initiators may be used alone or in combination of two or more.
In this embodiment, the amount of the polymerization initiator used is not particularly limited, but is preferably 0.001% by weight to 50% by weight, more preferably 0.005% by weight to 20% by weight, and particularly preferably 0.01% by weight to 10% by weight, based on the amount of the monomer A used in the polymerization reaction.

In this embodiment, the polymerization reaction is carried out at normal pressure, under pressurized sealed conditions, or under reduced pressure, and is preferably carried out at normal pressure for the sake of simplicity of the apparatus and operation. It is also preferable to carry out the reaction in an inert gas atmosphere such as nitrogen. The polymerization reaction temperature is preferably 40°C to 150°C, more preferably 40°C to 100°C. The polymerization reaction time is preferably in the range of 1 hour to 48 hours, more preferably in the range of 1 hour to 24 hours. These reaction temperature and reaction time conditions may be appropriately adjusted depending on the type and amount of monomer A used, and the type and amount of polymerization initiator used.

In this embodiment, after the polymerization reaction is completed, the obtained fluoropolymer is recovered by any method and, if necessary, subjected to post-treatment such as purification. As a method for recovering the polymer from the reaction solution, known methods such as concentration and reprecipitation can be used.

In this embodiment, the weight average molecular weight (hereinafter abbreviated as Mw) of the obtained fluoropolymer is preferably 1,000 to 1,000,000, more preferably 10,000 to 500,000, calculated as polystyrene by gel permeation chromatography (GPC).

As one preferred embodiment of the present invention, a fluorine-containing surface modifier composition can be mentioned which comprises at least a fluorine-containing polymer obtained by copolymerizing a monomer B which is copolymerizable or copolymerizable with the monomer A separately from the monomer A which is a raw material for the above-mentioned fluorine-containing polymer, and the obtained fluorine-containing polymer and a fluorine-based solvent.
Here, the monomer B which is copolymerizable or copolymerizable with the monomer A may be any monomer capable of forming a fluorine-containing polymer. The copolymerized fluorine-containing polymer has a structure having residue units derived from the monomer A and the monomer B.
Furthermore, there is no particular limitation on the monomer B as long as it is copolymerizable or copolymerizable with the monomer A. Furthermore, the monomer B may be a specific type, but it may also be two or more types of monomers other than the monomer A.
In the present invention, the monomer A which is a fluorine-containing (meth)acrylic acid ester represented by the general formula (2) can be applied in various ways as the compound structure represented by the general formula (2), and among them, a combination with a monomer B which copolymerizes or can copolymerize with the monomer A can be adopted after appropriate consideration. Furthermore, other copolymerization conditions can also be adopted after appropriate consideration.

In addition, the fluorine-containing polymer is composed of monomer A and monomer B which copolymerizes with monomer A. The mixing ratio of monomer A to monomer B during the polymerization reaction is preferably such that the weight ratio (A)/(B) of monomer A to monomer B is 1:99 to 99.9:0.1, and more preferably 10:90 to 99.9:0.1.

In this embodiment, monomer B is not particularly limited as long as it is a monomer that copolymerizes or can be copolymerized with monomer A, but it is preferably one or more selected from the group consisting of (meth)acrylic acid, esters of (meth)acrylic acid, styrenes, fatty acid vinyl esters, vinyl halides, vinylidene halides, fatty acid allyl esters, and acrylamides. Specific examples include (meth)acrylic acid, methyl, ethyl, butyl, isobutyl, t-butyl, propyl, 2-ethylhexyl, hexyl, decyl, lauryl, stearyl, isobornyl, behenyl, β-hydroxyethyl, glycidyl, phenyl, benzyl, 4-cyanophenyl, polyethylene glycol, polypropylene glycol, methoxypolyethylene glycol, methoxypolypropylene glycol esters, styrene, α-methylstyrene, p-methylstyrene, vinyl fluoride, vinyl chloride, vinyl bromide, vinylidene fluoride, vinylidene chloride, allyl heptanoate, allyl caprylate, allyl caproate, N-methylacrylamide, N-methylol acrylamide, and N-methylol methacrylamide. These monomers may be used alone or in a mixture of two or more.

In this embodiment, the polymerization method is not particularly limited, but for example, solution polymerization using a solvent can be performed.

In this embodiment, the solvent used in the solution polymerization is not particularly limited, and specific examples thereof include aromatic hydrocarbon solvents such as benzene, toluene, xylene, ethylbenzene, and tetralin; aliphatic or alicyclic hydrocarbon solvents such as n-hexane, n-heptane, mineral spirits, and cyclohexane; halogen-based solvents such as methyl chloride, methyl bromide, methyl iodide, methylene dichloride, chloroform, carbon tetrachloride, trichloroethylene, perchloroethylene, and orthodichlorobenzene; ester-based or ester ether-based solvents such as ethyl acetate, butyl acetate, methoxybutyl acetate, methyl cellosolve acetate, ethyl cellosolve acetate, and propylene glycol monomethyl ether acetate; ether-based solvents such as diethyl ether, tetrahydrofuran, 1,4-dioxane, methyl cellosolve, ethyl cellosolve, butyl cellosolve, and propylene glycol monomethyl ether; acetone, methyl ethyl ketone, methyl isobutyl ketone, di- Examples of the solvent include ketone-based solvents such as n-butyl ketone and cyclohexanone; alcohol-based solvents such as methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, tert-butanol, 2-ethylhexyl alcohol and benzyl alcohol; amide-based solvents such as N,N-dimethylformamide and N,N-dimethylacetamide; sulfoxide-based solvents such as dimethyl sulfoxide; heterocyclic compound-based solvents such as N-methyl-2-pyrrolidone; trifluoromethylbenzene, 1,3-bis(trifluoromethyl)benzene, 1,4-bis(trifluoromethyl)benzene, 1,1,1,2,2-pentafluoro-3,3-dichloropropane, 1,1,2,2,3-pentafluoro-1,3-dichloropropane, pentafluorobutane, decafluoropentane, perfluorohexane, perfluorocyclohexane, perfluorodecalin, hexafluorobenzene, and fluorine-based solvents such as hydrofluoroethers. These solvents may be used alone or in combination of two or more.
In this embodiment, the amount of the solvent used in the solution polymerization is not particularly limited, but is preferably 1 to 200 times by weight, more preferably 2 to 100 times by weight, based on the total amount of the monomer A and the monomer B used in the polymerization reaction.

In this embodiment, the polymerization reaction can be progressed by using, for example, a polymerization initiator. The polymerization initiator is not particularly limited, but examples thereof include azo compounds such as 2,2'-azobisisobutyronitrile, 2,2'-azobis(2-methylbutyronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 1,1'-azobis(1-cyclohexanecarbonitrile), 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), and 2-(carbamoylazo)isobutyronitrile; peroxides such as benzoyl peroxide, di-t-butyl peroxide, diisopropyl peroxydicarbonate, t-butyl peroxypivalate, and lauryl peroxide; and persulfates such as potassium persulfate and ammonium persulfate. These polymerization initiators may be used alone or in combination of two or more.
In this embodiment, the amount of the polymerization initiator used is not particularly limited, but is preferably 0.001% by weight to 50% by weight, more preferably 0.005% by weight to 20% by weight, and particularly preferably 0.01% by weight to 10% by weight, based on the total amount of the monomer A and the monomer B used in the polymerization reaction.

In this embodiment, the polymerization reaction is carried out at normal pressure, under pressurized sealed conditions, or under reduced pressure, and is preferably carried out at normal pressure for the sake of simplicity of the apparatus and operation. It is also preferable to carry out the reaction in an inert gas atmosphere such as nitrogen. The polymerization reaction temperature is preferably 40°C to 150°C, more preferably 40°C to 100°C. The polymerization reaction time is preferably in the range of 1 hour to 48 hours, more preferably in the range of 1 hour to 24 hours. These reaction temperature and reaction time conditions may be appropriately adjusted depending on the type and amount of monomer A used, and the type and amount of polymerization initiator used.

In this embodiment, after the polymerization reaction is completed, the obtained fluoropolymer is recovered by any method and, if necessary, subjected to post-treatment such as purification. As a method for recovering the polymer from the reaction solution, known methods such as concentration and reprecipitation can be used.

In this embodiment, the weight average molecular weight (hereinafter abbreviated as Mw) of the obtained fluoropolymer is preferably 1,000 to 1,000,000, more preferably 5,000 to 500,000, calculated as polystyrene by gel permeation chromatography (GPC).

The fluorine-containing polymer of the present invention can be dissolved in a fluorine-based solvent and used as a fluorine-containing surface modifier composition containing the fluorine-containing polymer and the fluorine-based solvent. By preparing the composition in a solution form, it can be made into a form that can be used to treat a substrate by coating, immersion, etc.
The uses of the surface modifier composition of the present invention are not particularly limited, but it can be used, for example, as a coating agent, a water and oil repellent, a rust inhibitor, an antifouling agent, a water resistance agent, a stripping agent, a mold release agent, an oil barrier agent, an agent for preventing flux creeping up, and the like.

In the fluorine-containing surface modifier composition of the present invention, the fluorine-based solvent contains at least one selected from the group consisting of hydrofluoroethers, hydrofluorocarbons, perfluorocarbons, hydrochlorofluorocarbons and chlorofluorocarbons. Specific examples include methyl nonafluorobutyl ether (HFE7100), ethyl nonafluorobutyl ether (HFE7200), 1,1,1,2,3,4,4,5,5,5-decafluoro-3-methoxy-2-(trifluoromethyl)pentane (HFE7300), pentafluorobutane, decafluoropentane, perfluorohexane, perfluorocyclohexane, perfluorodecalin, hexafluorobenzene, 1,3-bis(trifluoromethyl)benzene, 1,4-bis(trifluoromethyl)benzene, 1,1,1,2,2-pentafluoro-3,3-dichloropropane, 1,1,2,2,3-pentafluoro-1,3-dichloropropane, and 2,2,3,3-tetrachlorohexafluorobutane. Among them, methyl nonafluorobutyl ether (HFE7100), ethyl nonafluorobutyl ether (HFE7200), 1,1,1,2,3,4,4,5,5,5-decafluoro-3-methoxy-2-(trifluoromethyl)pentane (HFE7300), decafluoropentane, perfluorohexane, perfluorocyclohexane, perfluorodecalin, and the like are preferred from the viewpoint of having no flash point and being easy to handle. These solvents may be used alone or in combination of two or more. These solvents may be appropriately selected and used depending on the purpose of use. The use of a fluorine-based solvent is useful in that it can dissolve the fluorine-containing polymer uniformly and can provide a composition with low flammability and low erosion to resins.
The surface modifier composition of the present invention preferably contains 0.01 to 50% by weight, more preferably 0.05 to 20% by weight, of the fluorine-containing polymer based on the total amount of the fluorine-containing polymer and the fluorine-based solvent.

The surface modifier composition of the present invention may be prepared by mixing the obtained fluorine-containing polymer with the above-mentioned fluorine-based solvent, or the fluorine-containing polymer solution obtained by solution polymerization using a fluorine-based solvent may be used as it is as a surface modifier, or the fluorine-containing polymer solution obtained by solution polymerization using a fluorine-based solvent may be further diluted with a solvent to prepare the surface modifier composition.

Substrates to be treated with the surface modifier composition of the present invention include, but are not limited to, metals, plastics, ceramics, etc. In particular, the surface modifier composition of the present invention is useful when treating electronic components such as printed circuit boards, because it has low erosive properties.

The treatment of a substrate with the surface modifier composition of the present invention can be carried out by any commonly used method, such as brushing, applying with a wipe or rag, dipping, spraying with a mister, spraying with a spray gun, or aerosol spraying.

By using the fluorine-containing surface modifier composition of the present invention, it is possible to impart excellent water and oil repellency to the surface of a substrate. Furthermore, the composition is composed of perfluoroalkyl groups having 6 or less carbon atoms, which are considered to have low bioaccumulation, and has low flammability and corrosion resistance to resins.

Examples of the present invention are shown below, but the present invention is not limited to these examples.
The following instruments were used for the analysis:
<NMR>
Apparatus: Bruker AVANCE II 400
Internal standard: tetramethylsilane, trifluoromethylbenzene Solvent: acetone-d6
<GPC>
Apparatus: Tosoh HLC-8320GPC
Column: TSKgel G4000H/G3000H/G2500H/G2000H
Eluent: hexafluoroisopropanol or tetrahydrofuran Flow rate: 0.3 mL/min or 1 mL/min
<DSC>
Apparatus: TA Instruments DSC Q2000
Scanning speed: 10° C./min

<Contact angle measurement>
For the measurement sample (polymer shown below), the static contact angles of pure water and diiodomethane, and the dynamic contact angle of pure water by the expansion/contraction method were measured.
Specifically, a predetermined amount of a polymer sample to be measured was dissolved in a fluorine-based solvent, and then filtered through a syringe filter with a pore size of 0.45 μm to prepare a polymer solution of a predetermined concentration. This polymer solution was formed into a film on a silicon wafer with a diameter of 2 inches by spin coating.
For the spin coating, a manual spin coater ACT-300AII manufactured by Active was used, and for the contact angle measurement, a contact angle meter DMs-401 manufactured by Kyowa Interface Science was used.

Here, the static contact angle is measured to measure wettability and the like. When a droplet is brought into contact with a solid surface and lands on it, the angle it makes with the sample surface is defined as the contact angle θ. In the present invention, the θ/2 method is used for analysis. The larger the static contact angle, the better the water and oil repellency.
The dynamic contact angle is also measured to quantify the liquid removability. The contact angle when the surface spreads (expands) is called the (dynamic) advancing angle, and the contact angle when the surface contracts is called the (dynamic) receding angle. In the present invention, the expansion/contraction method is used, and the analysis is performed using the perfect circle fitting method. The smaller the contact angle hysteresis, which is the difference between the advancing contact angle and the receding contact angle obtained by dynamic contact angle measurement, the better the dynamic water repellency.

５０ｍＬのフラスコに化合物（３）５．００ｇ（東ソー・ファインケム製）、２－ブタノン１５．００ｇ（富士フイルム和光純薬製）、２，２’－アゾビス（イソブチロニトリル）１０．８ｍｇ（富士フイルム和光純薬製、１ｍｏｌ％）を仕込み、窒素置換した後、７０℃で１２時間撹拌した。
反応終了後、２層に分離した反応液の上澄みをデカンテーションした後、メチルノナフルオロブチルエーテル５ｇ（３Ｍ製）を加えた。得られた溶液をヘキサン２０ｇに滴下してポリマーを沈殿させ、上澄み液をデカンテーションした後、真空乾燥して、４．００ｇの重合体１を無色固体として得た。収率は８０％（重量換算、以下同じ）であった。得られた目的物のＧＰＣによるＰＭＭＡ換算で測定される数平均分子量Ｍｎは８，１００、分散度Ｍｗ／Ｍｎは１．８であった。ＤＳＣ測定を行ったところ、ガラス転移温度は２７．０℃であった。 Example 1
Synthesis of Polymer 1

A 50 mL flask was charged with 5.00 g of compound (3) (manufactured by Tosoh Finechem Co., Ltd.), 15.00 g of 2-butanone (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), and 10.8 mg of 2,2'-azobis(isobutyronitrile) (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., 1 mol%), and the mixture was purged with nitrogen and stirred at 70°C for 12 hours.
After the reaction was completed, the supernatant of the reaction solution separated into two layers was decanted, and then 5 g of methyl nonafluorobutyl ether (manufactured by 3M) was added. The obtained solution was dropped into 20 g of hexane to precipitate the polymer, and the supernatant was decanted and then vacuum dried to obtain 4.00 g of polymer 1 as a colorless solid. The yield was 80% (weight conversion, the same applies below). The number average molecular weight Mn of the obtained target product measured in PMMA conversion by GPC was 8,100, and the dispersity Mw/Mn was 1.8. When DSC measurement was performed, the glass transition temperature was 27.0°C.

実施例１において、化合物（３）に替えて化合物（４）５．００ｇ（東ソー・ファインケム製）を用いた以外、同様の操作で４．０９ｇの重合体２を白色固体として得た。収率は８２％であった。得られた目的物のＧＰＣによるＰＭＭＡ換算で測定される数平均分子量Ｍｎは１３，０００、分散度Ｍｗ／Ｍｎは２．７であった。ＤＳＣ測定を行ったところ、融解温度は４２．７℃であった。 Example 2
Synthesis of Polymer 2

In Example 1, 4.09 g of polymer 2 was obtained as a white solid by the same procedure as in Example 1, except that 5.00 g of compound (4) (manufactured by Tosoh Finechem) was used instead of compound (3). The yield was 82%. The number average molecular weight Mn of the obtained target product measured in terms of PMMA by GPC was 13,000, and the dispersity Mw/Mn was 2.7. When DSC measurement was performed, the melting temperature was 42.7°C.

Comparative Example 1
Synthesis of Polymer 3 In Example 1, 3.50 g of Polymer 2 was obtained as a colorless solid by the same procedure as in Example 1, except that 5.00 g of 3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluoro-n-octyl methacrylate (manufactured by Tokyo Chemical Industry Co., Ltd.) was used instead of compound (3). The yield was 70%. The number average molecular weight Mn of the obtained target product measured in terms of PMMA by GPC was 6,400, and the polydispersity Mw/Mn was 1.5. When DSC measurement was performed, the glass transition temperature was 24.8°C.

Comparative Example 2
Synthesis of Polymer 4 In Example 1, 4.00 g of Polymer 2 was obtained as a colorless viscous product by the same procedure as in Example 1, except that 5.00 g of 3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluoro-n-octyl acrylate (manufactured by Tokyo Chemical Industry Co., Ltd.) was used instead of compound (3). The yield was 80%. The number average molecular weight Mn of the obtained target product measured in terms of polystyrene by GPC was 5,500, and the polydispersity Mw/Mn was 1.4. When DSC measurement was performed, the glass transition temperature was −16.1° C.

Example 3
20 mg of the polymer 1 obtained in Example 1 was dissolved in 1.98 g of decafluoropentane (manufactured by Mitsui Chemours Fluoroproducts), and then filtered through a syringe filter with a pore size of 0.45 μm to obtain a 1.0 wt % polymer solution, to prepare a surface modifier composition. This composition was formed into a film on a silicon wafer with a diameter of 2 inches by spin coating (slope 5 seconds, then 2,000 rpm for 10 seconds, and then slope for another 5 seconds). For the obtained thin film, the static contact angles (droplet volume 2 μL) of pure water and diiodomethane, and the dynamic contact angle of pure water by the expansion/contraction method were measured by the above-mentioned method.

Example 4
The same measurement as in Example 3 was carried out using Polymer 2 instead of Polymer 1.

Comparative Example 3
The same measurement as in Example 3 was carried out using Polymer 3 instead of Polymer 1.

Comparative Example 4
The same measurement as in Example 3 was carried out using Polymer 4 instead of Polymer 1.

The results obtained above are shown in Table 1.

From the results in Table 1, the thin films formed by the surface modifier containing the fluorine-containing polymer of the present invention and a fluorine-based solvent shown in Examples 3 and 4 can be seen to have the following characteristics when compared with the thin films formed by the surface modifier containing a conventional fluorine-containing polymer having a perfluoroalkyl group having 6 or less carbon atoms shown in Comparative Examples 3 and 4.
From the measurement results of the static contact angle with pure water, it can be seen that the results of Examples 3 and 4 are higher than those of Comparative Examples 3 and 4, and therefore have excellent water repellency, and from the measurement of the static contact angle with diiodomethane, it can be seen that the results of Examples 3 and 4 are higher than those of Comparative Examples 3 and 4, and therefore have excellent oil repellency.
From the results of measuring the dynamic contact angle with pure water, the results of Examples 3 and 4 for the advancing contact angle were roughly the same as those of Comparative Examples 3 and 4, but the results of Examples 3 and 4 for the receding contact angle were higher than those of Comparative Examples 3 and 4, and furthermore, the contact angle hysteresis was small, indicating that the results are excellent in terms of water droplet removal properties.

Example 5
Synthesis of Polymer 5 In a 10 mL test tube, 0.80 g of compound (3) (manufactured by Tosoh Finechem Co., Ltd.), 0.20 g of 2-ethylhexyl methacrylate (manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd.), 4.00 g of 2-butanone (manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd.), and 10.0 mg of t-butyl peroxyoctoate (manufactured by NOF Corp.) were placed, purged with nitrogen, and then stirred at 75° C. for 12 hours.
After the reaction was completed, the supernatant of the reaction solution separated into two layers was decanted and then vacuum dried to obtain 0.62 g of polymer 5 as a colorless solid. The yield was 62%. The number average molecular weight Mn of the obtained target product measured in terms of polystyrene by GPC was 16,000, and the polydispersity Mw/Mn was 1.3. The copolymerization ratio measured by ¹ H NMR was 21% (weight conversion, the same applies below) of the residue unit consisting of 2-ethylhexyl methacrylate in the copolymer.

Example 6
Synthesis of Polymer 6 In Example 5, 0.69 g of Polymer 6 was obtained as a colorless solid by the same procedure except that 0.20 g of dodecyl methacrylate (manufactured by Tokyo Chemical Industry Co., Ltd.) was used instead of 2-ethylhexyl methacrylate. The yield was 69%. The number average molecular weight Mn of the obtained target product measured in terms of polystyrene by GPC was 11,000, and the polydispersity Mw/Mn was 1.5. The copolymerization ratio measured by ¹ H NMR was 24% of the residue unit consisting of dodecyl methacrylate in the copolymer.

Comparative Example 5
Synthesis of Polymer 7 In Example 5, 0.76 g of polymer 7 was obtained as a colorless solid by the same procedure except that 0.80 g of 3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluoro-n-octyl methacrylate (manufactured by Tokyo Chemical Industry Co., Ltd.) was used instead of compound (3). The yield was 76%. The number average molecular weight Mn of the obtained target product measured in terms of polystyrene by GPC was 11,000, and the polydispersity Mw/Mn was 1.8. The copolymerization ratio measured by ¹ H NMR was 18% of the residue unit consisting of 2-ethylhexyl methacrylate in the copolymer.

Comparative Example 6
Synthesis of Polymer 8 In Example 6, 0.77 g of polymer 8 was obtained as a colorless solid by the same procedure except that 0.80 g of 3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluoro-n-octyl methacrylate (manufactured by Tokyo Chemical Industry Co., Ltd.) was used instead of compound (3). The yield was 77%. The number average molecular weight Mn of the obtained target product measured in terms of polystyrene by GPC was 16,000, and the polydispersity Mw/Mn was 1.6. The copolymerization ratio measured by ¹ H NMR was 19% of the residue unit consisting of dodecyl methacrylate in the copolymer.

Example 7
20 mg of the polymer 5 obtained in Example 5 was dissolved in 1.98 g of ethyl nonafluorobutyl ether (manufactured by 3M), and then filtered through a syringe filter with a pore size of 0.45 μm to obtain a 1.0 wt % polymer solution, to prepare a surface modifier composition. This composition was formed into a film on a silicon wafer with a diameter of 2 inches by spin coating (slope 5 seconds, then 2,000 rpm for 10 seconds, and then slope for another 5 seconds). The static contact angles (droplet volume 2 μL) of pure water and diiodomethane of the obtained thin film were measured by the above-mentioned method.
Example 8
The same measurement as in Example 7 was carried out using Polymer 6 instead of Polymer 5.

Comparative Example 7
The same measurement as in Example 7 was carried out except that Polymer 7 was used in place of Polymer 5.

Comparative Example 8
The same measurement as in Example 7 was carried out using Polymer 8 instead of Polymer 5.

From the results in Table 2, the thin films formed by the surface modifier containing the fluorine-containing polymer of the present invention and a fluorine-based solvent shown in Examples 7 and 8 can be seen to have the following characteristics when compared with the thin films formed by the surface modifier containing a conventional fluorine-containing polymer having a perfluoroalkyl group having 6 or less carbon atoms shown in Comparative Examples 7 and 8.
Comparing Example 7 and Comparative Example 7, both are composed of the same 2-ethylhexyl methacrylate as monomer B. In this case, the static contact angle of Example 7 is higher than that of Comparative Example 7 in terms of pure water, and is therefore excellent in water repellency, whereas the static contact angle of diiodomethane is comparable between the two. This shows that polymer 5, in which monomer A is composed of compound (3), is more water repellent, and the composition of the present invention is therefore excellent in water repellency.
Comparing Example 8 and Comparative Example 8, both are composed of the same dodecyl methacrylate as monomer B. In this case, the static contact angle of Example 8 is higher than that of Comparative Example 8, indicating excellent water repellency, while the static contact angle of diiodomethane is comparable. This shows that polymer 6, in which monomer A is composed of compound (3), is more water repellent, and the composition of the present invention is therefore excellent in water repellency.

These results show that the thin film formed by the surface modifier containing the fluorine-containing polymer of the present invention and a fluorine-based solvent exhibits superior water and oil repellency compared to the thin film formed by the surface modifier containing the conventional fluorine-containing polymer having a perfluoroalkyl group having 6 or less carbon atoms.

By using a composition containing the fluorine-containing polymer of the present invention and a fluorine-based solvent, a fluorine-containing surface modifier composition that has excellent water and oil repellency, low flammability, and low corrosion resistance to resins can be provided, which is industrially useful.

Claims (5)

A fluorine-containing surface modifier composition comprising a fluorine-containing polymer having a residue unit represented by the following general formula (1) and a fluorine-containing solvent which is at least one selected from the group consisting of hydrofluoroethers, hydrofluorocarbons and perfluorocarbons :
(In formula (1), Rf ¹ is a perfluoroalkyl group having 1 to 6 carbon atoms, Rf ² is a perfluoroalkylene group having 1 to 6 carbon atoms, n is an integer of 1 to 4, and R is a hydrogen atom or a methyl group.) 2. The fluorine-containing surface modifier composition according to claim 1, wherein the fluorine-containing polymer is obtained by polymerizing a fluorine-containing (meth)acrylic acid ester represented by the following general formula (2):
(In formula (1), Rf ¹ is a perfluoroalkyl group having 1 to 6 carbon atoms, Rf ² is a perfluoroalkylene group having 1 to 6 carbon atoms, n is an integer of 1 to 4, and R is a hydrogen atom or a methyl group.) The fluorine-containing surface modifier composition according to claim 1, wherein the fluorine-containing polymer is composed of monomer A and monomer B which is copolymerized with monomer A, and the weight ratio (A)/(B) of monomer A to monomer B is 1:99 to 99.9:0.1. The fluorine-containing surface modifier composition according to claim 1 or 3, wherein monomer B is at least one selected from the group consisting of (meth)acrylic acid, esters of (meth)acrylic acid, styrenes, fatty acid vinyl esters, vinyl halides, vinylidene halides, fatty acid allyl esters, and acrylamides. The fluorine-containing surface modifier composition according to any one of claims 1 to 4, which contains the fluorine-containing polymer in an amount of 0.01% by weight to 50% by weight based on the total amount of the fluorine-containing polymer and the fluorine-based solvent.