JP7415778B2 - Fluoropolymer and method for producing fluoropolymer - Google Patents

Description

The present invention relates to a fluoropolymer and a method for producing a fluoropolymer.

Fluorine-containing polymers have excellent properties such as weather resistance, heat resistance, and chemical resistance, so they are used in a variety of fields, and one example of their use is coating the surface of metal and resin substrates. .
Here, depending on the type of material constituting the base material, the adhesion of the fluorine-containing polymer to the base material may be insufficient, and various studies have been made to improve this problem.
For example, in the Examples section of Patent Document 1, a fluororesin composite composition of a tetrafluoroethylene-perfluoro(alkyl vinyl ether) copolymer (hereinafter also referred to as "PFA") and silica nanoparticles is described. It is disclosed that the obtained molded article has excellent adhesion to a copper substrate.

Japanese Patent Application Publication No. 2008-115336

As mentioned above, Patent Document 1 shows that a molded article of a fluororesin composite composition has excellent adhesion to a copper base material. However, when only a fluorine-containing polymer such as PFA is used without using inorganic fine particles such as silica nanoparticles, there still exists a problem of adhesion to various types of substrates made of different materials.

The present invention was made in view of the above problems, and an object of the present invention is to provide a fluorine-containing polymer that has excellent adhesiveness to various types of substrates and a method for producing the same.

As a result of intensive study on the above-mentioned problem, the present inventors discovered that the desired effect can be obtained by using a fluorine-containing polymer containing a specific amount or more of units based on a specific monomer, and the present invention has been achieved. .

That is, the inventors have found that the above problem can be solved by the following configuration.
[1] From 1,1,2-trifluoro-1-propene, 1,1,2,3-tetrafluoro-1-propene, and 1,1,2,3,3-pentafluoro-1-propene A fluoropolymer having a unit (a) based on at least one monomer (a) selected from the group consisting of A fluorine-containing polymer in an amount of 25 to 100 mol% based on the unit.
[2] The fluoropolymer according to [1], wherein the fluoropolymer has a melting point of 100 to 330°C.
[3] The fluoropolymer of [1] or [2], wherein the fluoropolymer essentially consists of the unit (a).
[4] The above unit (a) is a unit based on 1,1,2-trifluoro-1-propene, a unit based on 1,1,2,3-tetrafluoro-1-propene, and 1,1, The fluoropolymer according to any one of [1] to [3], which consists of only one type of units based on 2,3,3-pentafluoro-1-propene.
[5] A method for producing a fluoropolymer according to any one of [1] to [4], which comprises 1,1,2-trifluoro-1-propene, 1,1,2,3-tetrafluoro-1 - in the presence of at least one monomer (a) selected from the group consisting of propene and 1,1,2,3,3-pentafluoro-1-propene, and a polymerization initiator, A method for producing a fluoropolymer, which comprises polymerizing the monomer (a).
[6] The polymerization of the monomer (a) is carried out in the presence of a solvent, and the ratio of the mass of the monomer (a) to the total mass of the solvent and the monomer (a) is The method for producing a fluoropolymer according to [5], wherein the content is 3 to 90% by mass.
[7] The method for producing a fluoropolymer according to [5], wherein the monomer (a) is polymerized substantially without using a solvent.

According to the present invention, it is possible to provide a fluoropolymer with excellent adhesiveness to various types of substrates and a method for producing the same.

The meanings of terms in the present invention are as follows.
A numerical range expressed using "~" means a range that includes the numerical values written before and after "~" as lower and upper limits.
"Unit" is a general term for an atomic group derived from one molecule of the above monomer that is directly formed by polymerization of monomers, and an atomic group obtained by chemically converting a part of the above atomic group. be. A "unit based on a monomer" is also simply referred to as a "unit" hereinafter.

[Fluorine-containing polymer]
The fluoropolymer of the present invention (hereinafter also referred to as "specific fluoropolymer") includes 1,1,2-trifluoro-1-propene (hereinafter also referred to as "1243yc"), 1,1, From 2,3-tetrafluoro-1-propene (hereinafter also referred to as "1234yc") and 1,1,2,3,3-pentafluoro-1-propene (hereinafter also referred to as "1225yc") It has a unit (a) based on at least one monomer (a) selected from the group consisting of:
Further, the content of the unit (a) is 25 to 100 mol% based on the total units contained in the specific fluoropolymer.
Specific fluorine-containing polymers have excellent adhesion to various types of substrates. Although the details of this reason are not clear, unit (a) has a C-H bond in the side chain and has a predetermined amount of unit (a), so it can be used on a variety of base materials with different materials. It is presumed that it exhibited excellent adhesion.
In addition, since the specific fluoropolymer has a C-F bond in the main chain of the unit (a), it also has the characteristics of conventional fluoropolymers, such as excellent weather resistance, heat resistance, and chemical resistance. ing.

Monomer (a) is at least one monomer selected from the group consisting of 1243yc, 1234yc and 1225yc.
Monomer (a) may be used alone or in combination of two or more types, but it is preferable to use one type alone from the viewpoint of easy control of the physical properties of the specific fluoropolymer.

The specific fluoropolymer may have only one type of unit or two or more types of units among 1243yc units, 1234yc units, and 1225yc units. Among these, it is preferable to have only one type of unit from the viewpoints that the effect of the present invention is more excellent and that the physical properties of the specific fluoropolymer can be easily controlled. That is, the specific fluoropolymer is preferably a 1243yc homopolymer, a 1234yc homopolymer, or a 1225yc homopolymer.

The content of the unit (a) is 25 to 100 mol % based on the total units contained in the specific fluoropolymer, which provides better effects of the present invention and forms a flat film with excellent processability. In terms of the amount of water that can be used, it is preferably 50 mol% or more, more preferably 80 mol% or more, even more preferably 90 mol% or more, and particularly preferably 95 mol% or more.
In the present invention, when the specific fluoropolymer has a content of units (a) of 95 mol% or more based on all units contained, it is also referred to as "substantially consisting of units (a)."

The specific fluoropolymer may have units based on monomers other than monomer (a) (hereinafter also referred to as "other units").
Specific examples of other monomers include fluorine-containing monomers such as tetrafluoroethylene (TFE), vinylidene fluoride (VdF), and hexafluoropropylene (HFP).
The content of other units is preferably 0 to 75 mol%, more preferably 0 to 50 mol%, even more preferably 0 to 10 mol%, and particularly preferably 0 to 1 mol%.

(Physical properties of fluoropolymer)
The melting point of the specific fluoropolymer is preferably 100 to 330°C, more preferably 110 to 300°C, particularly preferably 120 to 240°C.
In the present invention, the melting point of a fluoropolymer is defined as the melting point when the fluoropolymer is heated at a rate of 10°C/min using a differential scanning calorimeter (for example, an apparatus similar to DSC204F1 (manufactured by Netsch)). The melting peak is recorded and is the temperature (°C) corresponding to the maximum value of the melting peak of the fluoropolymer.

The thermal decomposition temperature of the specific fluoropolymer is preferably 200 to 500°C, more preferably 220 to 450°C, particularly preferably 240 to 430°C.
In the present invention, the thermal decomposition temperature of the fluoropolymer is measured using a thermogravimetric differential thermal analyzer (TG-DTA) (for example, an apparatus based on STA7200 (manufactured by Hitachi High-Tech Science)).

(Applications of fluoropolymer)
The use of the specific fluoropolymer is not particularly limited, but it can be used, for example, to coat various substrates (eg, metal substrates, resin substrates) used in the semiconductor industry, automobile industry, chemical industry, etc.
The specified fluoropolymer may be molded as it is and used as a molded article, or the specified fluoropolymer and any additives (for example, colorants, reinforcing agents, antistatic agents, flame retardants, lubricants, etc.) may be used as molded articles. ), the fluoropolymer composition may be molded and used as a molded article.
Specific examples of the molding method include melt molding, injection molding, extrusion molding, blow molding, press molding, rotational molding, electrostatic coating, and the like.
Specific examples of the shape of the molded body include sheet, tube, and three-dimensional shapes.

[Method for producing fluoropolymer]
The method for producing a specific fluoropolymer (hereinafter also referred to as "this production method") involves polymerizing the above monomer (a) in the presence of the above monomer (a) and a polymerization initiator. This is the manufacturing method.

Monomer (a) is as described above and is available as a commercial product.

The polymerization initiator is not particularly limited, but from the viewpoint of polymerizability of monomer (a), a radical polymerization initiator is preferable, and a radical polymerization initiator having a 10-hour half-life temperature of 15 to 150° C. is particularly preferable.
Examples of radical polymerization initiators with a 10-hour half-life temperature of 15 to 150°C include azo compounds such as azobisisobutyronitrile; non-fluorinated diacyl peroxides such as isobutyryl peroxide, octanoyl peroxide, benzoyl peroxide, and lauroyl peroxide. ; Peroxydicarbonates such as diisopropyl peroxydicarbonate (hereinafter also referred to as "IPP"); tert-butyl peroxypivalate (hereinafter also referred to as "PBPV"), tert-butyl peroxyisobutyrate, tert-butyl Peroxy esters such as peroxyacetate; fluorine-containing diacyl peroxides such as bis(heptafluorobutyryl) peroxide (hereinafter also referred to as "PFB"); persulfates such as potassium persulfate, sodium persulfate, and ammonium persulfate; It will be done.
The polymerization initiators may be used alone or in combination of two or more.
The amount of the polymerization initiator charged is preferably 0.01 to 10 parts by mass, more preferably 0.05 to 9 parts by mass, and 0.07 to 8 parts by mass, per 100 parts by mass of monomer (a). Parts by weight are particularly preferred.

Polymerization of monomer (a) may be performed in the presence of a solvent. Such polymerization methods include suspension polymerization, solution polymerization, and emulsion polymerization.
Examples of the solvent include water and organic solvents, with organic solvents being preferred. Specific examples of organic solvents include fluorine-based solvents and non-fluorine-based solvents. The organic solvents may be used alone or in combination of two or more.

Specific examples of fluorine-based organic solvents include fluoroalkanes, fluoroaromatic compounds, fluoroalkyl ethers, fluoroalkylamines, and fluoroalcohols.
The fluoroalkane is preferably a compound having 4 to 8 carbon atoms, such as C ₆ F ₁₃ H (AC-2000: product name, manufactured by AGC Corporation), C ₆ F ₁₃ C ₂ H ₅ (AC-6000: product name, (manufactured by AGC), and C ₂ F ₅ CHFCHFCF ₃ (Bertrel: product name, manufactured by DuPont).
Specific examples of fluoroaromatic compounds include hexafluorobenzene, trifluoromethylbenzene, perfluorotoluene, 1,3-bis(trifluoromethyl)benzene, and 1,4-bis(trifluoromethyl)benzene.
The fluoroalkyl ether is preferably a compound having 4 to 12 carbon atoms, such as CF ₃ CH ₂ OCF ₂ CF ₂ H (AE-3000: product name, manufactured by AGC), C ₄ F ₉ OCH ₃ (Novec-7100: Product name, manufactured by 3M Company), C ₄ F ₉ OC ₂ H ₅ (Novec-7200: Product name, manufactured by 3M Company), C ₂ F ₅ CF (OCH ₃ ) C ₃ F ₇ (Novec-7300: Product name, (manufactured by 3M).
Specific examples of fluoroalkylamine include perfluorotripropylamine and perfluorotributylamine.
Specific examples of fluoroalcohols include 2,2,3,3-tetrafluoropropanol, 2,2,2-trifluoroethanol, and hexafluoroisopropanol.

Examples of non-fluorine organic solvents include hydrocarbon solvents, ketone solvents, ether solvents, ester solvents, alcohol solvents, and amide solvents.
Specific examples of hydrocarbon organic solvents include hexane, heptane, and cyclohexane.
Specific examples of ketone organic solvents include acetone, methyl ethyl ketone, and methyl isobutyl ketone.
Specific examples of ether organic solvents include diethyl ether, tetrahydrofuran, and tetraethylene glycol dimethyl ether.
Specific examples of ester organic solvents include ethyl acetate and butyl acetate.
Specific examples of alcoholic organic solvents include isopropyl alcohol, ethanol, and n-butanol.
Examples of amide solvents include N,N-dimethylformamide (hereinafter also referred to as "DMF").

Among these, organic solvents with low chain transfer properties such as AC-2000, AE-3000, and DMF are preferred.

When the polymerization of monomer (a) is carried out in the presence of a solvent, from the viewpoint of polymerizability of monomer (a), the amount of monomer ( The mass ratio of a) is preferably 3 to 90% by mass, more preferably 5 to 85% by mass, and particularly preferably 8 to 70% by mass.

Polymerization of monomer (a) may be carried out substantially without using a solvent. Such polymerization methods include bulk polymerization.
In the present invention, "substantially no solvent is used" means that the ratio of the mass of monomer (a) to the total mass of the solvent and monomer (a) is greater than 90% by mass. do.

When polymerizing monomer (a), components other than monomer (a), a polymerization initiator, and a solvent may be used.
Specific examples of other components include the other monomers mentioned above, chain transfer agents, and polymerization inhibitors.

The reaction temperature during polymerization of monomer (a) is preferably 15 to 120°C, particularly preferably 20 to 80°C.
The reaction pressure during polymerization of monomer (a) is preferably 0 to 2.0 MPa, particularly preferably 0.2 to 1.5 MPa.
The reaction time for polymerizing monomer (a) is preferably 2 to 72 hours, particularly preferably 5 to 70 hours.

Hereinafter, the present invention will be explained in detail by giving examples. Examples 1 to 4 are examples, and Examples 5 to 7 are comparative examples. However, the present invention is not limited to these examples.

[Content of each unit in fluoropolymer]
The content (mol%) of each unit with respect to all units of the fluoropolymer was calculated based on ¹⁹ F-nuclear magnetic resonance (NMR) analysis.

[Physical properties of fluoropolymer]
The physical properties (thermal decomposition temperature and melting point) of the fluoropolymer were measured by the method described above.

〔Adhesiveness〕
The base material and the fluoropolymer disposed on the surface of the base material were placed in a sheet-like mold, and the mold was preheated under the following conditions. Preheating was performed at 170°C for 10 minutes in Examples 1 to 3, 210°C for 5 minutes in Example 4, 270°C for 5 minutes in Examples 5 and 6, and 200°C for 5 minutes in Example 7.
Subsequently, the base material and the fluoropolymer were pressed under the following conditions to obtain a laminate in which the base material and the fluoropolymer layer were laminated in this order. In Examples 1 to 3, 170°C for 1 minute at a pressure of 2MPa, in Example 4, 210°C for 5 minutes at a pressure of 2MPa, in Example 5, 320°C for 5 minutes at a pressure of 2MPa, and in Example 6, at a pressure of 2MPa. Preheating was carried out at 270°C for 5 minutes, and in Example 7, at 200°C for 5 minutes at a pressure of 2 MPa. Note that the thickness of the fluoropolymer layer in the laminate was 50 μm.
The appearance of the obtained laminate was visually confirmed, and the adhesiveness of the fluoropolymer was evaluated according to the following criteria.
Here, the adhesiveness was evaluated for each of a copper plate, an aluminum plate, a polyimide film (Upilex-125S 125 μm: product name, manufactured by Ube Industries, Ltd.), a PTFE film, and a SUS plate. The evaluation results are shown in Table 1.
◎: The entire fluoropolymer layer is adhered to the base material, and no peeling from the base material is observed.
○: Part of the fluoropolymer layer adheres to the base material.
×: The entire fluoropolymer layer has peeled off from the base material.

[Example 1]
The inside of a polymerization tank (autoclave) made of SUS316 and equipped with a stirrer and having an internal volume of 30 L was cooled to -40°C and the pressure was reduced using a vacuum pump.
Next, in a polymerization tank, 13.5 g of AC-2000 and a polymerization initiator solution (IPP:1,3-dichloro-1,1,2,2,3-pentafluoropropane = 50:50 (mass ratio) , manufactured by NOF Corporation) was introduced. Next, 1.5 g of 1243yc was introduced in a gaseous state into the polymerization tank. The polymerization tank was heated, and the time when the temperature inside the polymerization tank reached 60°C was defined as the time when polymerization started. Note that the reaction pressure was 0.24 MPa (gauge pressure). After 16 hours from the start of polymerization, the polymerization tank was cooled and residual gas was purged to terminate the polymerization. The slurry in the polymerization tank was taken out and vacuum dried at 80° C. for 12 hours to remove residual monomers and residual solvents to obtain the fluoropolymer of Example 1 (0.2 g, yield 15%).

[Example 2]
A fluoropolymer of Example 2 was obtained in the same manner as Example 1, except that no solvent was used and the amounts of each component were changed as shown in Table 1.

[Example 3]
A fluoropolymer of Example 3 was obtained in the same manner as in Example 1, except that the conditions for producing the fluoropolymer were changed as shown in Table 1.

[Example 4]
The fluoropolymer of Example 4 was produced in the same manner as in Example 1, except that the production conditions for the fluoropolymer were changed as shown in Table 1, and TFE was introduced in a gaseous state at the same time as monomer (a). Obtained.

[Example 5]
PFA (NAFLON TOMBO NO. 9000PFA: product name, manufactured by Nichias Corporation, tetrafluoroethylene-perfluoro(alkyl vinyl ether) copolymer) was used as the fluoropolymer in Example 5.

[Example 6]
ETFE (Fluon C-55AXP: product name, manufactured by AGC Corporation, ethylene-tetrafluoroethylene copolymer) was used as the fluoropolymer in Example 6.

[Example 7]
PVDF (Hylar 301F: product name, manufactured by Solvay, polyvinylidene fluoride) was used as the fluoropolymer in Example 7.

As shown in Table 1, a fluoropolymer in which the content of unit (a) is 25 to 100 mol% based on the total units contained in the fluoropolymer has excellent adhesion to a variety of substrates. was confirmed (Examples 1 to 4).

Claims (8)

From the group consisting of 1,1,2-trifluoro-1-propene, 1,1,2,3-tetrafluoro-1-propene, and 1,1,2,3,3-pentafluoro-1-propene A fluoropolymer having a unit (a) based on at least one selected monomer (a),
A fluoropolymer, wherein the content of the unit (a) is 80 to 100 mol% based on the total units contained in the fluoropolymer. The fluoropolymer according to claim 1, wherein the fluoropolymer has a melting point of 100 to 330°C. The fluoropolymer according to claim 1, wherein the content of the unit (a) is 90 to 100 mol% based on the total units contained in the fluoropolymer. The fluoropolymer according to any one of claims 1 to 3 , wherein the fluoropolymer consists essentially of the unit (a). The unit (a) is a unit based on 1,1,2-trifluoro-1-propene, a unit based on 1,1,2,3-tetrafluoro-1-propene, and 1,1,2,3 The fluoropolymer according to any one of claims 1 to 4 , comprising only one type of units among units based on ,3-pentafluoro-1-propene. A method for producing a fluoropolymer according to any one of claims 1 to 5 , comprising:
From the group consisting of 1,1,2-trifluoro-1-propene, 1,1,2,3-tetrafluoro-1-propene, and 1,1,2,3,3-pentafluoro-1-propene A method for producing a fluoropolymer, comprising polymerizing the monomer (a) in the presence of at least one selected monomer (a) and a polymerization initiator. Polymerization of the monomer (a) is carried out in the presence of a solvent,
The method for producing a fluoropolymer according to claim 6 , wherein the proportion of the mass of the monomer (a) to the total mass of the solvent and the monomer (a) is 3 to 90% by mass. . 8. The method for producing a fluoropolymer according to claim 7 , wherein the monomer (a) is polymerized substantially without using a solvent.