JPH0570522A - Fluorine-containing polymer - Google Patents

Abstract

PURPOSE:To obtain a fluorine-containing polymer having a repeating unit of a specific cyclic structure which has a low dielectric constant and a high volume resistivity, is excellent in transparency and gives a thin film coating, by polymerizing a specific fluorine-containing diolefin in the presence of a radical polymerization initiator. CONSTITUTION:A fluorine-containing diolefin of formula I (wherein n is 1-5) is polymerized in the presence of a radical polymerization initiator to obtain a fluorine-containing polymer having a repeating unit of a specific cyclic structure as represented by formula II and/or formula III (wherein n is as defined above). This polymer has such low refractive index, electric insulating property, weatherability, water absorption and heat resistance as possessed by conventional fluororesins. Further, this polymer is amorphous, so that a transparent resin can be obtained, which is useful as an optical disc, an optical lens or the like. Still further, this polymer is soluble in various solvents so that a solvent having a boiling point most suitable for various conditions in the use in a coating composition can be chosen. The obtained coating film is excellent in adhesion to various types of substrates, so that the polymer is suitable for use in a moisture-proof coating material for electronic components or the like.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a novel fluoropolymer.

[0002]

[Prior art and its problems] With the progress of advanced information society,
The demands on materials used in the fields of electronics and optoelectronics are becoming ever more stringent. That is, a material having a low dielectric constant and a high volume resistance value is required in the field of electronics, and a material having a low refractive index and good transparency is required in the field of optoelectronics. Further, it is desirable that these can be used not only as a so-called molded product but also as a coating agent capable of forming a thin film.

Polytetrafluoroethylene (PTFE)
The fluororesin typified by 1) is used in the electronics field as a printed circuit board and various insulating materials as a material having a low dielectric constant and a high volume resistance value. However,
Since the resin is a crystalline polymer, the molded body is opaque and therefore has limited applications in the field of optoelectronics. Furthermore, since the resin is insoluble in solvents, it should be used as a coating material. Is impossible.

On the other hand, in the field of optoelectronics such as optical fiber cladding, a methacrylate resin having a fluoroalkyl group in its side chain is used. The methacrylate resin can be used as a coating material because it can be dissolved not only in the molding process but also in an organic solvent. However, the resin has a refractive index n _D
At 1.37 to 1.42 and U of 400 μm or less
The light transmittance at the wavelength in the V region is poor, and the performance required in the electronics field is not satisfied.

Recently, as a polymer having good transparency even though it is a perfluoropolymer, for example, JP-A-1-1312
General formula in No. 15 publication

[0006]

[Chemical 3]

[In the formula, m represents 1 or 2. ] A polymer having a repeating unit represented by
No. 009 specification

[0008]

[Chemical 4]

Polymers having repeating units represented by the formula [k / l = 1/9 to 3/7] have been proposed. However, when these polymers are used as a coating material, a very expensive and special solvent such as Fluorinert FC75 [trade name, manufactured by 3M Co.] has to be used, which results in high cost and is obtained. The coating film has a drawback that it has poor adhesion to the substrate. Further, since a special perfluoromonomer is used in the production of these polymers, it has a drawback that the polymerization rate is low and it is difficult to obtain a high molecular weight polymer.

[0010]

An object of the present invention is to provide a fluoropolymer which does not have the above-mentioned drawbacks.

That is, the present invention has the following general formula: CH ₂ = CF (CF ₂ ) _n OCF = CF ₂ (1) [wherein n represents an integer of 1 to 5]. ] A fluorine-containing diolefin represented by the above formula is a polymer obtained by polymerizing in the presence of a radical polymerization initiator

[0012]

[Chemical 5]

[In the formula, n is the same as above. ] And / or

[0014]

[Chemical 6]

[In the formula, n is the same as above. ] The present invention relates to a fluoropolymer having a repeating unit having a cyclized structure.

The fluorine-containing diolefin represented by the above general formula (1) is preferably CH ₂ ═CFCF ₂ OCF═
_{CF 2, CH 2 = CF (} CF 2) may be exemplified ₂ OCF = CF ₂ or the like.

The synthetic examples of the above-mentioned fluorine-containing diolefins can be easily synthesized from acid fluoride as shown in the following reaction formula-1, for example.

Reaction formula-1

[0019]

[Chemical 7]

The acid fluoride used in the above reaction formula-1 is the synthetic route shown in the following reaction formula-2 when n = 1 and the synthesis shown in the following reaction formula-3 when n = 2 or 4. In the case of n = 3 or 5, it can be produced by the synthetic route shown in the following reaction formula-4.

Reaction formula-2

[0022]

[Chemical 8]

Reaction formula-3

[0024]

[Chemical 9]

Reaction formula-4

[0026]

[Chemical 10]

The above-mentioned fluorine-containing diolefin (1) is easily polymerized under ordinary radical polymerization conditions to obtain a high-molecular weight fluorine-containing polymer in a high yield. When radically polymerizing the fluorinated diolefin (1), any of bulk polymerization, solution polymerization, suspension polymerization and emulsion polymerization can be employed.

As the radical polymerization initiator used in the polymerization, a wide variety of conventionally known ones can be widely used, for example, azobisisobutyronitrile, azobisdimethylvaleronitrile, azobisdimethyleneisobutylamidine dihydrochloride and the like. Azo compound, diisopropyl peroxydicarbonate, isobutyryl peroxide, tert-butyl peroxyhivalate, heptafluorohebutyryl peroxide, trifluorodichloropropionyl peroxide, dodecafluoroheptanoyl peroxide, and other organic peroxides, K ₂ S ₂ O ₃ , (NH ₄ )
Examples include inorganic peroxides such as ₂ S ₂ O ₃ and radiation sources such as ⁶⁰ Co.

In the case of suspension polymerization, water and / or 1,1,2
-Trichloro-1,2,2-trifluoroethane, 1,
It is preferably carried out in the presence of a fluorohydrocarbon such as 1-dichloro-1,1,2,2-tetrafluoroethane. Emulsion polymerization also includes water and suitable emulsifiers such as ammonium perfluorooctanoate, perfluoro-3-oxa-.
It is preferably carried out in the presence of ammonium 2-methylhexanoate, sodium lauryl sulfonate and the like. Further, the solution polymerization is a solvent capable of dissolving the fluorinated diolefin (1),
For example, 1,1,2-trichloro-1,2,2-trifluoroethane, 1,1-dichloro-1,1,2,2-tetrafluoroethane, perfluorobenzene, perfluoroheptane, perfluorocyclohexane, perfluoroethane. It is preferable to carry out in at least one solvent selected from solvents such as fluorohydrocarbons such as fluorodioxane.

In the present invention, it is preferable to employ solution polymerization in order to prevent gelation due to intermolecular crosslinking reaction. The monomer concentration during solution polymerization is usually 50.
Weight% (hereinafter simply referred to as "%") or less, preferably 1 to
It is preferable to set it to about 30%, more preferably about 5 to 15%. The polymerization temperature varies depending on the solvent used and the like and cannot be generally stated, but it is usually about 0 to 100 ° C., preferably 1
It is about 0 to 50 ° C. The polymerization pressure is reduced pressure to 20 k.
It is preferably about g / cm ² G. Further, a chain transfer agent may be appropriately added to the polymerization reaction system in order to control the molecular weight of the resulting fluoropolymer. As such a chain transfer agent, conventionally known ones can be widely used, for example, pentane,
Cyclohexane, dimethyl ether, ethyl acetate, methanol and the like can be mentioned.

In producing the polymer of the present invention, within the range that the transparency and heat resistance of the obtained polymer are not impaired,
It is also possible to copolymerize the above-mentioned fluorine-containing diolefin (1) with another monomer. Examples of the other monomer include olefins such as ethylene, propylene and isobutene, and fluoroolefins such as tetrafluoroethylene, chlorotrifluoroethylene, hexafluoropropylene, vinylidene fluoride, vinyl fluoride, hexafluoroisobutene and perfluorovinyl ether. Examples thereof include vinyl ethers such as ethyl vinyl ether and butyl vinyl ether, and vinyl esters such as vinyl acetate. Among these, fluoroolefins are preferable because of their low refractive index and excellent electrical properties such as dielectric constant.

The fluoropolymer of the present invention is a transparent amorphous polymer. As the molecular weight of the polymer, the intrinsic viscosity [η] (in m-meta-xylene hexafluoride, 35
(° C) is usually about 0.01 to 3, but [η] is preferably about 0.05 to 2 and more preferably about 0.2 to 1 from the viewpoint of the toughness and moldability of the resulting polymer. From the viewpoint of ease of polymerization and solubility during the polymerization, n of the fluorinated diolefin (1) is preferably 1 to 3, and n = 1 from the viewpoint of easiness of synthesis of the fluorinated diolefin (1). Is particularly preferable.

[0033]

EFFECT OF THE INVENTION The polymer of the present invention has the characteristics of ordinary fluororesins, that is, low refractive index, electric insulation, weather resistance, low water absorption, heat resistance, etc. Since it is an amorphous polymer, it can be used as a transparent resin in compression molding, injection molding and extrusion molding, and can be effectively used as a clad agent for optical disks, optical lenses and optical fibers. Further, the polymer of the present invention includes trichlorotrifluoroethane (boiling point 48 ° C.), m-metaxylene hexafluoride (boiling point 115 ° C.), perfluorobenzene (boiling point 8
Since it dissolves in various solvents such as (2 ° C.), when the polymer is used as a coating material, the solvent having the optimum boiling point can be selected under various conditions, and the coating films obtained are surprisingly various. Base materials such as plastics such as polymethylmethacrylate, polycarbonate, polystyrene, metals such as iron, copper, zinc, tin, Si, Ga / As
Excellent adhesion to substrates such as semiconductor materials. Therefore, the polymer of the present invention is a moisture-proof coating material for electronic parts,
It can be suitably used as an antireflection agent for optical parts, a weather resistant film, an insulating film and the like. Further, the polymer of the present invention has a glass transition temperature of 60 ° C. or higher, and can be sufficiently used as a molding material because it is in a resin state at room temperature.

[0034]

EXAMPLES The present invention will be further clarified with reference to the following examples.

Example 1 A 200 cc glass reaction tank equipped with a stirrer and a thermometer was used to add C
H ₂ = CFCF ₂ OCF = CF ₂ 10 g, 1,1,2-
90 g of trichloro-1,2,2-trifluoroethane (hereinafter referred to as "R113") and 0.01 g of diisopropyl peroxydicarbonate (hereinafter referred to as "IPP")
I charged g. The reaction tank was cooled with dry ice-methanol, vacuum deaeration and nitrogen pressurization were repeated 3 times, then vacuum deaeration was carried out and polymerization was carried out at 30 ° C. for 24 hours. After completion of the polymerization reaction,
Polymer 9.1 according to the invention precipitated in a large amount of petroleum ether.
g was obtained.

The obtained polymer was dissolved in perfluorobenzene, ¹⁹ F-NMR and ¹ H-NMR were measured, and m-metaxylene hexafluoride (hereinafter referred to as "mXH"
F ”) and measured by ¹⁹ F-NMR.

[0037]

[Chemical 11]

And / or

[0039]

[Chemical formula 12]

It was found to be a polymer having a repeating unit of the cyclized structure represented by

The Tg of this polymer by DSC was 65 ° C.,
The thermal decomposition starting temperature was 370 ° C. MXH of the polymer
The intrinsic viscosity at F (35 ° C.) was [η] = 0.43, and the refractive index n ²⁷ _D was 1.363. 2 of the polymer
The light transmittance at 350 nm of a 00 μm film is 9
It was 0%, and was sufficiently transparent as compared with 29% of the light transmittance of the trifluoroethyl methacrylate polymer. Further, the polymer is R113, perfluorobenzene, mX
It was dissolved not only in fluorohydrocarbons such as HF, but also in methanol at a low concentration.

Example 2 The same apparatus as in Example 1 was used, but CH ₂ = CFCF ₂ OCF = C
F ₂ 10 g, perfluorobenzene 90 g and (H (C
0.01 g of F ₂ ) ₆ COO) ₂ was charged, the same degassing operation as in Example 1 was carried out, and then the reaction was carried out at 15 ° C. for 24 hours.

The amount of the polymer obtained was 7.2 g, and [η]
= 0.61. ¹⁹ F-NMR and ¹ H-NM
From R, it was found that the obtained polymer had a structure similar to that of Example 1.

Example 3 The same apparatus as in Example 1 was used, but CH ₂ = CFCF ₂ CF ₂ OC was used.
F = CF ₂ 10 g, R113 90 g and IPP 0.
01 g was charged and polymerization was carried out under the same operations and conditions as in Example 1.

The amount of the polymer obtained was 8.8 g, and [η]
Was 0.38. ¹⁹ F-NMR and ¹ H-NM
When R was measured,

[0046]

[Chemical 13]

And / or

[0048]

[Chemical 14]

It was found to be a polymer having a repeating unit of the cyclized structure represented by

The Tg of this polymer by DSC is 103.
C., the thermal decomposition starting temperature was 370.degree. The refractive index n ²⁷ _D of the polymer was 1.357. 200μ of the polymer
The light transmittance of the m film at 350 nm was 90%. Further, the polymer was dissolved in fluorohydrocarbons such as R113, perfluorobenzene, and mXHF.

Comparative Example 1 CF ₂ ═CFCF ₂ OCF═C was used in the same apparatus as in Example 1.
F _{2 (} 10 g), R11390 g and IPP (0.01 g) were charged, and polymerization was carried out under the same operations and conditions as in Example 1.

The amount of the obtained polymer was only 3.7 g, and [η] in Fluorinert FC75 was only 0.16. Further, the obtained polymer was dissolved in perfluorobenzene, and ¹⁹ F-NMR was measured.

[0053]

[Chemical 15]

It was found to be a polymer having a repeating unit having a cyclized structure represented by
Did not dissolve at all.

Example of Use The polymer obtained in Example 1 and the polymer obtained in Comparative Example 1 were dissolved in perfluorobenzene to a concentration of 10%, and a glass epoxy substrate [Japan Test Panel Co., Ltd. Manufactured] to a film thickness of 10 μm. After drying at room temperature for 24 hours, scratch the coating with a cutter in a grid pattern (100 1 mm squares) and immerse in water for 24 hours.
When peeling was observed after a lapse of time, all the polymer of Example 1 remained (100/100), whereas Comparative Example 1
The polymer of 1 was all peeled (0/100).

Claims (1)

[Claims] 1. A general formula CH ₂ ═CF (CF ₂ ) _n OCF═CF ₂ [wherein n represents an integer of 1 to 5]. ] A fluorine-containing diolefin represented by the following formula is a polymer obtained by polymerizing in the presence of a radical polymerization initiator. [In the formula, n is the same as above. ] And / or [In the formula, n is the same as above. ] A fluoropolymer having a repeating unit having a cyclized structure represented by