JP5320266B2 - Fluoropolymer and coating agent - Google Patents

Description

  The present invention relates to a fluoropolymer and a coating agent.

  Conventionally, in coating agents that are applied to the surface of textile products, leather products and the like to impart water and oil repellency, fluorine having a fluoroalkyl group having 8 or more carbon atoms as an active ingredient from the viewpoint of excellent water repellency. In many cases, a polymer is used (see, for example, paragraphs [0018] and [0020] of Patent Document 1).

  When the fluoropolymer having a perfluoroalkyl group having 8 or more carbon atoms is decomposed, perfluorooctanoic acid (PFOA) may be generated. Since this PFOA compound has a concern of accumulation in a living body, in recent years, in the field of water and oil repellents, a substitute for a fluorine-based polymer having a fluoroalkyl group having 8 or more carbon atoms is used. It is being considered.

JP 2006-299016 A Japan Society for the Promotion of Science-Fluorine Chemistry 155 Committee, "Introduction to Fluorine Chemistry", Second Print, Sankyo Publishing, published on March 20, 2005, p. 267

  As an alternative to a fluoropolymer having a fluoroalkyl group having 8 or more carbon atoms, a fluoropolymer having a perfluoroalkyl group having 6 or less carbon atoms can be considered. However, the known fluoropolymer having a perfluoroalkyl group having 6 or less carbon atoms has a particularly significant decrease in dynamic contact angle as compared with the fluoropolymer having a perfluoroalkyl group having 8 or more carbon atoms. . This is considered due to the low crystallinity of perfluoroalkyl groups having 6 or less carbon atoms. Because of such circumstances, it has been considered that when a perfluoroalkyl group having 6 or less carbon atoms is used as a component of the coating agent, sufficient water repellency cannot be imparted to the substrate (see Non-Patent Document 1). ).

  The present invention has been completed based on the above circumstances, and when used as a component of a coating agent, can provide a substrate with sufficient water repellency. As a result, the carbon number is 8 or more. An object of the present invention is to provide a fluoropolymer that can be used as a component of a coating agent in place of the perfluoroalkyl group-containing fluoropolymer, and to provide a coating agent that provides sufficient water repellency to a substrate And

  As a result of intensive studies to solve the above problems, a monomer containing a perfluoroalkyl group having 6 or less carbon atoms and a cyclic monomer having a cyclic part composed of carbon and hydrogen and 50 to 85% by mass It has been found that when a fluorine polymer obtained by polymerizing 15% by mass or more and 50% by mass or less of a fluorine monomer is used as a component of the coating agent, sufficient water repellency can be imparted to the substrate.

That is, the present invention is a fluoropolymer containing a perfluoroalkyl group having a prime number of 6 or less, and the perfluoroalkyl group-containing monomer represented by the following general formula (1) is 50% by mass to 85% by mass. When, a fluorine 50 wt% to 15 wt% of the non-fluorine-based monomer containing no less, will be polymerized, wherein the fluorine-free monomer, wherein the cyclic monomer having a cyclic moiety consisting of carbon and hydrogen nonfluorinated The linear alkyl group-containing compound having 10 or more carbon atoms is contained in an amount of 30% by mass to 70% by mass with respect to the mass of the non-fluorine monomer. The cyclic monomer is a compound having no carbon-carbon double bond in the cyclic portion, and the substituent of the cyclic portion is (meth) acryloyl. Only one, or (meth) fluoropolymer, characterized in that only an acryloyl group and an alkyl group, and a coating agent containing the fluorine-based polymer.

〔一般式（１）中、Ｒ１は水素原子またはメチル基、ｍは０〜４の整数、ｎは１〜６の整数を示す。〕

[In General Formula (1), R1 is a hydrogen atom or a methyl group, m is an integer of 0-4, and n is an integer of 1-6. ]

  According to the present invention, when used as a component of a coating agent, the substrate can be provided with sufficient water repellency. As a result, instead of a fluoroalkyl group-containing fluoropolymer having 8 or more carbon atoms, A fluoropolymer that can be used as a component of a coating agent can be provided. Moreover, according to this invention, the coating agent which gives sufficient water repellency to a base material can be provided.

In the present invention, the non-fluorine monomer includes a cyclic monomer of 30% by mass to 70% by mass and a linear chain having 10 or more carbon atoms of 30% by mass to 70% by mass with respect to the mass of the non-fluorine monomer. And an alkyl group-containing compound .
The fluorine-based polymer having such a structure is easily dissolved in a fluorine-free hydrocarbon solvent that does not contain fluorine (for example, n-hexane, isohexane, n-heptane, etc.).

Cyclic monomers are cyclic moiety, a carbon - Ri compound der having no carbon-carbon double bonds, in particular, cyclohexyl acrylate, cyclohexyl methacrylate, isobornyl acrylate that, and is isobornyl methacrylate of one or more selected preferable. Although the details of the effects of including a cyclic monomer in a non-fluorinated monomer are unclear, the fluoropolymer produced using a non-fluorinated monomer containing a cyclic monomer is rigid, so the movement of the perfluoroalkyl group Is suppressed, and it may be considered that it has the same water repellency as a highly crystalline fluororesin. Moreover, since the said fluoropolymer is bulky, it is thought that the surface becomes dense and prevents the entry of water molecules.

  The fluorine polymer of the present invention is preferably dissolved in a fluorine-free hydrocarbon solvent that does not contain fluorine. As the fluorine-free hydrocarbon solvent, it is preferable to use one or more selected from n-hexane, n-heptane and isohexane.

  According to the present invention, when used as a component of a coating agent, the substrate can be provided with sufficient water repellency. As a result, instead of a fluoroalkyl group-containing fluoropolymer having 8 or more carbon atoms, A fluoropolymer that can be used as a component of a coating agent can be provided. Moreover, according to this invention, the coating agent which gives sufficient water repellency to a base material can be provided.

  The fluorine-based polymer of the present invention is a fluorine-based polymer containing a perfluoroalkyl group having 6 or less carbon atoms, and contains a perfluoroalkyl group-containing monomer represented by the following general formula (1) and fluorine. It can be obtained by polymerizing a non-fluorinated monomer.

〔一般式（１）中、Ｒ１は水素原子またはメチル基、ｍは０〜４の整数、ｎは１〜６の整数を示す。〕

[In General Formula (1), R1 is a hydrogen atom or a methyl group, m is an integer of 0-4, and n is an integer of 1-6. ]

  In the following, “(meth) acrylate” means a group of methacrylic acid ester (methacrylate) and acrylic acid ester (acrylate).

  Specific examples of the perfluoroalkyl group-containing monomer represented by the general formula (1) (hereinafter also referred to as “fluorine monomer”) include perfluorohexyl ethyl (meth) acrylate, perfluorohexyl (meth) acrylate, Fluoropentylpropyl (meth) acrylate, perfluoropentylethyl (meth) acrylate, perfluorobutylethyl (meth) acrylate, perfluorobutylmethyl (meth) acrylate, perfluoropropylethyl (meth) acrylate, perfluoropropylmethyl (meta ) Acrylate, perfluoroethylethyl (meth) acrylate, perfluoroethylmethyl (meth) acrylate, and the like. These may be used alone or in combination of two or more. Among these compounds, those having 5 to 6 carbon atoms are preferable from the viewpoint of obtaining a fluoropolymer capable of imparting excellent water repellency.

In the present invention, the non-fluorinated monomer includes a cyclic monomer having a cyclic portion composed of carbon and hydrogen as an essential component.
As the cyclic monomer, a compound having no carbon-carbon double bond in the cyclic portion is preferable, and a compound selected from cyclohexyl (meth) acrylate, cycloheptyl (meth) acrylate, and isobornyl (meth) acrylate is particularly preferable. These cyclic monomers can be used alone or in combination of two or more.

The fluorine-based polymer of the present invention has a fluorine-based monomer of 50% by mass to 85% by mass and a non-fluorine-based monomer of 15% by mass to 50% by mass with respect to the total mass of the fluorine-based monomer and the non-fluorine-based monomer. The following can be obtained by polymerizing:
By polymerizing the fluorine-based monomer and the non-fluorine-based monomer at the above ratio, sufficient water repellency and sufficient oil repellency can be imparted to the base material, and the solubility in the hydrocarbon solvent can be improved. A high fluoropolymer is obtained.

  If the amount of the fluorinated monomer is less than 50% by mass relative to the total mass of the fluorinated monomer and the non-fluorinated monomer, sufficient water repellency cannot be obtained, and the amount of the fluorinated monomer exceeds 85% by mass. It becomes difficult to dissolve in a solvent.

  The non-fluorinated monomer preferably contains a linear alkyl group-containing compound having 10 or more carbon atoms in addition to the cyclic monomer. A fluorine-based polymer obtained by polymerizing a non-fluorinated monomer containing a cyclic monomer and a linear alkyl group-containing compound having 10 or more carbon atoms and a fluorine-based monomer is used as a solvent (for example, for producing a coating agent) This is because the solubility in n-hexane, isohexane, n-heptane, etc. is high.

  Examples of the linear alkyl group-containing compound having 10 or more carbon atoms include decyl (meth) acrylate, dodecyl (meth) acrylate, tridecyl (meth) acrylate, tetradecyl (meth) acrylate, pentadecyl (meth) acrylate, hexadecyl (meth) Examples include acrylate, stearyl (meth) acrylate, and eicosyl (meth) acrylate. These linear alkyl group-containing compounds can be used alone or in combination of two or more. As the linear alkyl group-containing compound having 10 or more carbon atoms, a (meth) acrylate containing a linear alkyl group having 10 to 20 carbon atoms is preferable.

  In the present invention, the non-fluorine monomer containing 30% by mass to 70% by mass of the cyclic monomer and 30% by mass to 70% by mass of the linear alkyl group-containing compound with respect to the mass of the non-fluorine monomer. It is preferable to use it. A fluorine-based polymer obtained by polymerizing a non-fluorine-based monomer and a fluorine-based monomer containing a cyclic monomer and a linear alkyl group-containing compound in the above proportion has high solubility in a solvent used for preparing a coating agent. Because.

  The non-fluorine-based monomer may contain a water-soluble monomer in addition to the above monomer. When a fluorine-based polymer obtained by reacting a non-fluorine-based monomer containing a water-soluble monomer with a fluorine-based monomer is used as a component of the coating agent, the adhesion to the substrate to which the coating agent is applied is improved. This is preferable.

  As the water-soluble monomer, a (meth) acrylate having an alkoxy group and polyethylene glycol is preferable, and one or more water-soluble monomers selected from methoxy polyethylene glycol acrylate and methoxy polyethylene glycol methacrylate are preferable. The water-soluble monomer is included in a proportion of 0.1% by mass or more and 1.5% by mass or less with respect to the total mass of the fluorinated monomer and the non-fluorinated monomer in consideration of the adhesion to the base material described above. Is preferred.

  The solvent used when polymerizing the fluorinated monomer and the non-fluorinated monomer may be any solvent that can dissolve or suspend the monomer (fluorinated monomer, non-fluorinated monomer), for example, water, toluene, xylene, or the like. , N-heptane, cyclohexane, tetrahydrofuran, n-hexane, isohexane and the like can be used alone or in combination of two or more.

  The polymerization initiator is not particularly limited as long as it has the ability to initiate radical polymerization. For example, a peroxide such as benzoyl peroxide, 2,2′-azobisisobutyronitrile (hereinafter referred to as AIBN). In addition to azo compounds such as 2,2′-azobis (isobutyric acid) dimethyl, persulfuric polymerization initiators such as potassium persulfate and ammonium persulfate can be used.

  The fluorine-based polymer of the present invention has a PMMA (polymethyl methacrylate) equivalent number average molecular weight (Mn) of 8,000 to 18,000 and a weight average molecular weight (Mw) of 15,000 to 23,000. Is preferred.

  In addition to water and oil repellents such as fibers, the fluoropolymer of the present invention can be used in a wide range of applications, for example, for applications such as moisture-proof coating agents for electronic substrates, to orient the fluorine on the surface and improve water repellency, , Chemical-resistant protective coatings that protect substrates from salt water, electrolytes, corrosive gases, etc., oil barrier agents that prevent the diffusion of lubricating oil used in micro motor bearings, and diffusion of lubricating oil used in HDD motor fluid bearings Oil barrier agent to prevent leakage, leakage prevention agent to prevent leakage of ink such as sign pens and ballpoint pens, anti-smudge agent for connectors and electronic parts, anti-creaking agent for insulation resin, prevention of adhesion of lead sealing resin for MF capacitor Can be used for agent, waterproof spray stock solution

The fluoropolymer of the present invention can be used as a coating agent by dissolving in a solvent. As the solvent for dissolving the fluoropolymer of the present invention, a solvent not containing fluorine can be used. Specifically, aliphatic solvents such as n-hexane, isohexane, n-heptane (fluorine-free carbonization). Equivalent to hydrogen solvents), ester solvents such as ethyl acetate and butyl acetate, and ketone solvents such as acetone. These solvents can be used alone or in admixture of two or more.
Among these, fluorine-free hydrocarbon solvents are preferable, and it is particularly preferable to use one or more selected from n-hexane, isohexane, and n-heptane. This is because the solubility of the fluoropolymer of the present invention is excellent.

  The fluoropolymer of the present invention is dissolved in a solvent so that the solid content concentration is 0.1 to 5% by mass. Various additives such as antioxidants, UV stabilizers, fillers, silicone oils, paraffinic solvents and plasticizers can be added to the coating solution of the present invention thus obtained in order to improve practicality. it can.

  As a coating method using the coating agent of the present invention, a known method such as a dipping method, a brush coating method, a spray method, or a roll coating method can be adopted, and the properties and form of the substrate using the coating agent are considered. And can be selected as appropriate.

<Example>
Hereinafter, the present invention will be further described by examples.
Example 1
(I) Synthesis of Fluoropolymer A In a 500 ml round bottom flask, 80 g of perfluorohexyl ethyl methacrylate, 13 g of stearyl methacrylate, 6 g of cyclohexyl methacrylate, and 1 g of methoxypolyethylene glycol methacrylate (polymerization degree 9) were weighed.
Here, since stearyl methacrylate is solid at normal temperature, it melt | dissolved in advance at 50 degreeC, and stirred, and measured.

30 g of n-heptane and 30 g of isohexane were added as a polymerization solvent to the flask in which various monomers were measured, and 0.5 g of AIBN was further added as a polymerization initiator. Next, a thermometer, a stirring blade, a cooling pipe, and an N ₂ pipe were set in the flask, and stirring was started at a rotation speed of 100 rpm.

While the contents in the flask were stirred, the space was replaced with nitrogen at room temperature for 30 minutes, hot water was added, and the heater was set at 80 ° C. to initiate polymerization. Nitrogen continued to flow until the end of the polymerization. The polymerization reaction was performed for 5 hours. Thereafter, the contents of the flask were cooled to room temperature to obtain a viscous liquid (fluorinated polymer A).
This fluoropolymer A was vacuum dried and subjected to gel permeation chromatography (GPC) measurement. As a result, the number average molecular weight (Mn) was 12,000 and the weight average molecular weight (Mw) was 23,000 in terms of PMMA. Met.

(Ii) Preparation of coating agent Fluoropolymer A was diluted with n-hexane so that the solid content concentration was 1% by mass to obtain the coating agent of Example 1.

(Example 2)
Fluoropolymer B was synthesized in the same manner as (i) of Example 1 except that 69 g of perfluorohexylethyl methacrylate, 18 g of stearyl methacrylate, and 12 g of cyclohexyl methacrylate were used. PMMA-converted Mn and Mw of the fluoropolymer B were measured in the same manner as in Example 1.
A coating agent of Example 2 was obtained in the same manner as (ii) of Example 1 except that the fluoropolymer B was used.

(Example 3)
Fluoropolymer C was prepared in the same manner as in Example 1 (i) except that 69 g of perfluorohexyl ethyl methacrylate and 10 g of stearyl methacrylate were used, and 20 g of isobornyl methacrylate was used instead of 6 g of cyclohexyl methacrylate. Synthesized. PMMA-converted Mn and Mw of the fluoropolymer C were measured in the same manner as in Example 1.
A coating agent of Example 3 was obtained in the same manner as (ii) of Example 1 except that the fluoropolymer C was used.

Example 4
69 g of perfluorohexyl ethyl methacrylate was used, 18 g of a mixture of alkyl groups containing 12 to 15 carbon atoms was used instead of 13 g of stearyl methacrylate, and 12 g of isobornyl methacrylate was used instead of 6 g of cyclohexyl methacrylate. Except for the above, a fluoropolymer D was synthesized in the same manner as in (i) of Example 1. PMMA-converted Mn and Mw of the fluoropolymer D were measured in the same manner as in Example 1.
Here, the mixture of the alkyl group-containing methacrylate having 12 to 15 carbon atoms is a mixture obtained by mixing 40% dodecyl methacrylate, 50% tridecyl methacrylate, and 10% pentadecyl methacrylate with respect to the mass of the mixture. .
A coating agent of Example 4 was obtained in the same manner as (ii) of Example 1 except that the fluoropolymer D was used.

(Example 5)
Fluoropolymer E was prepared in the same manner as in Example 1 (i) except that 60 g of perfluorohexylethyl methacrylate and 18 g of stearyl methacrylate were used, and 21 g of isobornyl methacrylate was used instead of 6 g of cyclohexyl methacrylate. Synthesized. PMMA conversion Mn and Mw of the fluoropolymer E were measured in the same manner as in Example 1.
A coating agent of Example 5 was obtained in the same manner as (ii) of Example 1 except that the fluoropolymer E was used.

(Example 6)
The same as (i) of Example 1 except that 75 g of perfluorobutylethyl methacrylate and 9 g of stearyl methacrylate were used instead of 80 g of perfluorohexylethyl methacrylate, and 15 g of isobornyl methacrylate was used instead of 6 g of cyclohexyl methacrylate. Thus, a fluoropolymer F was synthesized. PMMA conversion Mn and Mw of the fluoropolymer F were measured in the same manner as in Example 1. A coating agent of Example 6 was obtained in the same manner as (ii) of Example 1 except that the fluoropolymer F was used.

(Comparative Example 1)
69 g of a mixture of perfluoroalkyl ethyl acrylate having 8 to 12 carbon atoms was used instead of 80 g of perfluorohexyl ethyl methacrylate, 19 g of stearyl acrylate was used instead of 13 g of stearyl methacrylate, and cyclohexyl methacrylate was not used. A fluoropolymer G was synthesized in the same manner as in (i) of Example 1 except that 1 g of methoxypolyethylene glycol acrylate (polymerization degree 9) was used instead of 1 g of methoxypolyethylene glycol methacrylate. PMMA conversion Mn and Mw of the fluoropolymer G were measured in the same manner as in Example 1.
Here, the mixture of perfluoroalkylethyl acrylate having 8 to 12 carbon atoms is 50% perfluorooctylethyl acrylate, 30% perfluorodecylethyl acrylate, 10 perfluorododecylethyl acrylate with respect to the mass of the mixture. % Mixture.
A coating agent of Comparative Example 1 was obtained in the same manner as in (ii) of Example 1 except that the fluoropolymer G was used.

(Comparative Example 2)
Fluoropolymer H was synthesized in the same manner as in (i) of Example 1 except that 19 g of stearyl methacrylate was used and cyclohexyl methacrylate was not used. PMMA-converted Mn and Mw of the fluoropolymer H were measured in the same manner as in Example 1.
A coating agent of Comparative Example 2 was obtained in the same manner as in (ii) of Example 1 except that the fluoropolymer H was used.

(Comparative Example 3)
Except that 40 g of perfluorohexyl ethyl methacrylate and 29 g of stearyl methacrylate were used and 30 g of isobornyl methacrylate was used instead of 6 g of cyclohexyl methacrylate, the fluoropolymer I was prepared in the same manner as in (i) of Example 1. Synthesized. PMMA-converted Mn and Mw of the fluoropolymer I were measured in the same manner as in Example 1.
A coating agent of Comparative Example 3 was obtained in the same manner as (ii) of Example 1 except that the fluoropolymer I was used.

(Comparative Example 4)
Fluoropolymer J was prepared in the same manner as in (i) of Example 1 except that 90 g of perfluorohexyl ethyl methacrylate and 6 g of stearyl methacrylate were used, and 3 g of isobornyl methacrylate was used instead of 6 g of cyclohexyl methacrylate. Synthesized. PMMA-converted Mn and Mw of the fluoropolymer J were measured in the same manner as in Example 1.
Since the fluoropolymer J did not dissolve in n-hexane and a coating agent could not be produced, the evaluation test described later could not be performed.

(Evaluation test)
Test pieces were prepared according to the following procedure using the coating agents of Examples 1 to 6 and the coating agents of Comparative Examples 1 to 3.
The coating agent was applied for 4 seconds from a position 20 cm away from the test substrate, using a spray gun (manufactured by Anest Iwata Corporation, LPH-50) adjusted to a flow rate of 28-30 g / min. The test substrate coated with the coating agent was air-dried for 10 seconds, and then the coating agent was applied again for 4 seconds to obtain a test piece.
As a test base material, a tanned leather cut into a size of 15 mm × 60 mm was used.

(1) Slipping angle The dynamic contact angle (rolling angle) was measured by the sliding method using Kyowa Interface Chemical Co., Ltd., automatic contact angle meter DM500, and the results are shown in Tables 1 and 2. The amount of water was measured at 56 μl.
The tumbling angle refers to the tilt angle when liquid is deposited on a horizontal solid surface and the solid sample is gradually tilted and the liquid starts to slide downward. Is excellent.
In this evaluation test, if the sliding angle was 45 ° or less and there was no water residue, it was judged that the product had sufficient water repellency.

(2) Oil soaking time (described as “oil resistant (sinking)” in the table)
2 μl of n-hexadecane was dropped on the test piece, and the time until the hexadecane completely soaked (soaking time) was measured. The results are shown in Tables 1 and 2. The longer the soaking time, the better the oil resistance. If the soaking time was 10 minutes or longer, it was judged that the oil had sufficient oil repellency. In the table, “m” indicates “minute”, and “S” indicates “second”.

  Tables 1 and 2 show the monomers, polymerization initiators, polymerization solvents, reaction conditions, and molecular weights of the fluoropolymers A to J (number average molecular weight Mn, weight average molecular weight) used for the synthesis of the fluoropolymers A to J. Mw) is also shown.

  In the table, “perfluoroalkyl (mixture of 8, 10, 12) ethyl acrylate” means “mixture of perfluoroalkyl ethyl acrylate having 12 to 15 carbon atoms” and “alkyl (mixture of 12 to 15)”. The term “methacrylate” means “mixture of alkyl group-containing methacrylate having 12 to 15 carbon atoms”.

From the results described in Table 1 and Table 2, the following was found.
A coating agent containing a fluoropolymer H produced without using a cyclic monomer (Comparative Example 2), and a fluoropolymer obtained by polymerizing 40% by mass of a fluoromonomer and 60% by mass of a non-fluorine monomer. The coating agent containing Comparative I (Comparative Example 3) could not give sufficient water and oil repellency to the substrate.
On the other hand, the coating agents (Examples 1 to 6) containing the fluoropolymer of the present invention (fluorinated polymers A, B, C, D, E, F) have sufficient repellent properties on the substrate. It was found that water and sufficient oil repellency can be imparted.

  Among the coating agents of Examples, those using the coating agents of Examples 1, 3 and 4 have a falling angle of 30 ° or less and a fluorine having a perfluoroalkyl group having 8 or more carbon atoms. It can be said that excellent water repellency equivalent to or better than that of the coating agent containing the polymer G (Comparative Example 1) can be imparted to the substrate.

  Moreover, in the case of using the coating agents of Example 2, Example 3, and Example 4, the time required for soaking is longer than that of the coating agent of Comparative Example 1, and excellent oil repellency is imparted to the substrate. Can be said.

  From the above, the fluoropolymer of the present invention can provide a substrate with sufficient water repellency and sufficient oil repellency when used as a component of a coating agent, and as a result, a fluorocarbon having 8 or more carbon atoms. It can be said that it can be used as a component of the coating agent in place of the alkyl group-containing fluoropolymer.

<Other embodiments>
The present invention is not limited to the embodiments described with reference to the above description and drawings. For example, the following embodiments are also included in the technical scope of the present invention.
(1) In the above-described examples, the coating agent of the present invention was used by applying it to leather. However, the coating agent of the present invention can also be used by applying it to other substrates such as cloth.

Claims (5)

A fluoropolymer containing a perfluoroalkyl group having 6 or less carbon atoms,
Perfluoroalkyl group-containing monomer represented by the following general formula (1) 50% by mass to 85% by mass and 15% by mass to 50% by mass of a fluorine-free non-fluorinated monomer are polymerized. ,
The non-fluorinated monomer includes a cyclic monomer having a cyclic portion composed of carbon and hydrogen in an amount of 30% by mass to 70% by mass with respect to the mass of the non-fluorinated monomer, and a straight chain having 10 or more carbon atoms. The alkyl group-containing compound is contained in an amount of 30% by mass to 70% by mass with respect to the mass of the non-fluorine monomer,
The cyclic monomer is a compound having no carbon-carbon double bond in the cyclic portion, and the substituent of the cyclic portion is only a (meth) acryloyl group or a (meth) acryloyl group and an alkyl group only. fluoropolymer, characterized in that there.

[In General Formula (1), R1 is a hydrogen atom or a methyl group, m is an integer of 0-4, and n is an integer of 1-6. ] 2. The fluoropolymer according to claim 1, wherein the cyclic monomer is at least one selected from cyclohexyl acrylate, cyclohexyl methacrylate, isobornyl acrylate, and isobornyl methacrylate . A coating agent comprising the fluoropolymer according to claim 1 or 2 . A coating agent obtained by dissolving the fluorine-containing polymer according to claim 1 or 2 in a fluorine-free hydrocarbon solvent not containing fluorine . Before SL fluorine-free hydrocarbon solvent, n- hexane, coating agent according to claim 4, characterized in that n- heptane, and one or more selected from isohexane.