JPH05155936A - Fluoropolymer - Google Patents

Abstract

PURPOSE:To provide a fluoropolymer comprising repeating units each containing a specified ring structure and having excellent transparency and a glass transition temperature suitable to withstand the use at high temperature. CONSTITUTION:A fluoropolymer comprising repeating units of the formula (wherein R is fluoro or 1-10 C perfluoroalkyl) and having an intrinsic viscosity of 0.1-5.0 dl/g when measured in perfluoro(2-butyltetrahydrofuran) at 30 deg.C.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a fluoropolymer and a copolymer having a repeating unit represented by formula (A).

[0002]

[Chemical 2]

[0003]

2. Description of the Related Art Fluorine-containing polymers, especially perfluoropolymers, have excellent chemical stability, but lack transparency due to their crystallinity. When the ratio of the copolymerization component is increased to increase the transparency, there are problems that the softening temperature is lowered and the elastic modulus at high temperature is lowered. Usually, the softening point temperature of an amorphous polymer is determined by the glass transition temperature Tg, and before and after this, many physical properties such as mechanical properties and electrical properties change greatly. Therefore, in applications requiring high transparency while maintaining heat resistance and chemical stability, an amorphous polymer having a sufficiently high glass transition temperature is desired. CF ₂ ═CFO (CF ₂ ) _n C in JP-A-1-13125
It has been shown that F = CF ₂ alone undergoes cyclopolymerization to give a polymer having the cyclic structure of the general formula (B), being amorphous, excellent in light transmittance, and soluble in a solvent. However, in the case of a polymer of n = 1, Tg = 69 ° C., and in the case of n = 2, Tg = 1
Since the temperature is 08 ° C., the heat distortion temperature is not so high and there is a problem that it is insufficient for use at high temperatures.

[0004]

[Chemical 3]

[0005]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned drawbacks of fluoropolymers, and provides a novel polymer having an appropriate glass transition temperature capable of withstanding high temperature use while maintaining transparency. It is intended to be provided.

[0006]

Means for Solving the Problems The present inventors have conducted extensive studies on various fluorine-containing monomers based on the recognition of the above problems, and as a result, found that a polymer having a repeating unit containing a specific ring structure It was newly found that a polymer having a high Tg of about 100 ° C., excellent in transparency and solvent-soluble can be obtained. That is, the present invention has a repeating unit represented by the general formula (A) (wherein R is fluorine or a perfluoroalkyl group having 1 to 10 carbon atoms), and is in perfluoro (2-butyltetrahydrofuran) at 30 ° C. Intrinsic viscosity measured at 0.1-5.0 dl / g
The present invention provides a fluoropolymer which is

[0007]

[Chemical 4]

The fluorine-containing polymer in the present invention is disclosed in Japanese Patent Application No.
It is obtained by polymerizing a fluorine-containing monomer represented by the general formula (C) disclosed in -229603 (wherein R is fluorine or a perfluoroalkyl group having 1 to 10 carbon atoms).

[0009]

[Chemical 5]

As shown by the general formula (C), the fluorine-containing monomer in the present invention is characterized in that the double bond as the reaction site is present in the 6-membered ring and is perfluoro. It has never been known that a perfluoromonomer having such a 6-membered ring structure is polymerized.

As a result of extensive studies, the present inventor has found that the fluorine-containing monomer is radically polymerized to obtain a polymer. Further, they have found that the polymer has excellent physical properties useful in a wide range of industrial fields. That is,
The fluoropolymer of the present invention has excellent transparency, is soluble in a solvent,
It has properties such as low refractive index, low dielectric constant, low water absorption, and excellent heat resistance and chemical resistance.

The reason why the polymer of the present invention is soluble in a solvent is not clear, but it is considered that the polymer has a 6-membered ring structure in the main chain and is amorphous. The polymer is soluble in solvents such as perfluoro (2-butyltetrahydrofuran), perfluorotetrabutylamine and hexafluorobenzene. This enables processing means such as coating and dipping.

The molecular weight of the fluoropolymer of the present invention is represented by the intrinsic viscosity (dl / g) at 30 ° C. in perfluoro (2-butyltetrahydrofuran), and this value is between 0.1 and 5.0. preferable. When it is less than 0.1, it does not have sufficient strength, and when it exceeds 5.0, the solubility is remarkably reduced. The molecular weight of the fluoropolymer of the present invention can be adjusted by using a conventionally known or known chain transfer agent in the polymerization reaction.

The fluoropolymer in the present invention may be a copolymer, and by changing the copolymerization composition, fluorocopolymers having different Tg can be obtained while maintaining transparency. Further, by selecting the type of the comonomer, it is possible to improve the adhesion of the fluoropolymer to various base materials and to add a cross-linking site.

The comonomer to be copolymerized may be radically copolymerized alone, or two or more appropriate comonomers may be used in combination to carry out a multi-component copolymerization reaction, and a monomer having radical polymerizability is particularly preferable. Without being limited thereto, a fluorine-containing type, a hydrocarbon type and the like can be exemplified over a wide range. When a hydrocarbon-based monomer is used, it is preferable that the essence of the fluorinated copolymer is not impaired, but it is possible to increase the fluorine content by fluorinating if necessary.

In the present invention, it is usually desirable to select a fluorine-containing monomer such as fluoroolefin or fluorovinyl ether as a comonomer. For example,
Tetrafluoroethylene, perfluoromethyl vinyl ether, perfluoropropyl vinyl ether, or perfluoro vinyl ether having a functional group such as a carboxylic acid group or a sulfonic acid group is a preferred specific example, and vinylidene fluoride, vinyl fluoride, chloro Examples include trifluoroethylene and the like.

In the case of a copolymer containing these monomers, it is desirable that the content of the repeating unit (A) is at least 10 mol% in order to maintain the amorphous property. Considering at least 2
It is preferably 0 mol%.

In the present invention, when tetrafluoroethylene is used as a comonomer to be copolymerized, a copolymer can be obtained in a high yield in any composition, but a polymer having a high tetrafluoroethylene content shows crystallinity and is not transparent. Disappear. A composition in which transparency is impaired is not clear, but a copolymer having a content of the repeating unit (A) of about 30 mol% has no crystallinity and is soluble in a solvent.

Further, as a comonomer to be copolymerized in the present invention, a cyclopolymerizable fluorine-containing monomer having one carbon-carbon double bond having different polymerizability at each molecular end is also a preferable example. The following are examples of the cyclopolymerizable fluorine-containing monomer having one carbon-carbon double bond having different polymerizability at each molecular end.

[0020]

[Chemical 6]

[0021]

[Chemical 7]

[0022]

[Chemical 8]

When the cyclopolymerizable fluorine-containing monomer is used, an amorphous and transparent solvent-soluble copolymer can be obtained in any composition. Further, copolymers having various Tg's can be obtained by changing the copolymer composition.

In the present invention, a usual radical polymerization is used as a polymerization method. That is, the polymerization method is not particularly limited as long as it can radically proceed, and examples thereof include organic and inorganic radical initiators, polymerization by light, ionizing radiation or heat. As the polymerization method, bulk polymerization, solution polymerization, suspension polymerization and emulsion polymerization can be used.

The fluorine-containing polymer of the present invention can employ melt molding such as extrusion molding and injection molding, and processing means such as coating with a solution, casting and dipping, whereby the polymer of the present invention can be obtained. Have high T
g, high elastic modulus, high light transmittance, low refractive index, low dielectric constant, low surface free energy, chemical stability, and other various physical properties.

For example, in the case of plates, pipes, tubes, and other molded products, PTF has a high elastic modulus.
It retains strength up to high temperatures compared to E, PFA, etc.,
In addition, since it has the property of being excellent in chemical stability, it is useful in parts where structural parts such as piping, valves, and observation windows of plants of various chemical factories come into direct contact with chemicals. Further, since the fluoropolymer of the present invention has excellent thermal stability, it does not require additives such as a plasticizer and a heat stabilizer during the melt molding of the above-mentioned molded product, and therefore, in the food industry, in the bioindustry It has an advantage that impurities are prevented from being mixed in the product.

The use of light transmissivity is particularly
Since it has a transmittance of ultraviolet light of 250 nm or more of 90% or more and is not deteriorated by ultraviolet rays, it can be used as an optical transmission member such as a lens or an optical fiber in various optical devices using ultraviolet rays. Since it has small dispersion even in visible light, it is used as a lens for chromatic aberration correction.

The fluorine-containing polymer of the present invention has a low refractive index and is useful as a low reflection processing agent. An antireflection effect can be obtained by forming a film of the fluorine-containing polymer of the present invention on the surfaces of spectacle lenses, optical lenses, various optical members, photomask dustproof covers, show windows, showcases and the like.

Since the fluoropolymer of the present invention has a low dielectric constant, it has the effect of increasing the calculation speed when it is used as a protective film for a semiconductor device. Further, since the water absorption rate is low, there is an effect that the dielectric constant is not affected by humidity. The fluorine-containing polymer homogenous film of the present invention or a film laminated with a resin such as polyimide is useful as a circuit board.

It is possible to impart water repellency to the surface of various substrates by utilizing the low surface free energy. Perfluoro (2-butyltetrahydrofuran) or perfluoro which is a solvent of the present fluorine-containing copolymer. Tetrabutylamine has the advantage that it can be coated without damaging the substrate itself, and that the formed film is tough.

[0031]

The fluorine-containing polymer of the present invention has a ring structure in the main chain and thus has a high Tg, is soluble in a solvent, and is amorphous and transparent. Further, by changing the content of the repeating unit (A), a copolymer having various Tg can be obtained while maintaining transparency and solubility. The homopolymers and copolymers obtained by the present invention do not have crystallinity and show high transparency and high light transmittance, and since they are fluorine-containing polymers, they are ordinary hydrocarbon-based polymers. It is considered that it has a lower refractive index than that of the above resin and has excellent low water absorption, weather resistance and chemical resistance. However, it goes without saying that the above description is intended to help understanding of the present invention and does not limit the present invention.

[0032]

【Example】

Example 1 5.0 g of 2,3,5,5,6-pentafluoro-6-trifluoromethyl-1,4-dioxene and 0.02 g of bisisopropyl peroxydicarbonate as a polymerization initiator were added. The product was placed in a pressure-resistant glass ampoule having a volume of 50 ml. After freezing and degassing the system three times, 40 in a water bath
Shake at 5 ° C for 5 hours. The obtained solution was poured into acetone, and the precipitate was vacuum dried at 100 ° C. for 20 hours. As a result, 0.2 g of a polymer was obtained. The intrinsic viscosity of this polymer is 30 in perfluoro (2-butyltetrahydrofuran).
It was 0.10 dl / g at ℃.

Example 2 5.0 g of 2,3,5,5,6-pentafluoro-6-trifluoromethyl-1,4-dioxene, 50 g of ion-exchanged water, and 0.20 of C ₈ F ₁₇ COONH ₄ . 38g, Na
₂ HPO ₄ · 2H ₂ O 0.25g, NaH ₂ PO ₄ ·
0.145 g of 12H ₂ O and 0.12 g of ammonium persulfate as a polymerization initiator were placed in a stainless steel autoclave having an internal volume of 100 ml. After the pressure degassing operation was repeated 3 times with N ₂ gas in the system, the reaction was carried out at 30 ° C. for 7 days. The contents were taken out, and the precipitate obtained by freezing and thawing was washed with water and further washed with methanol.
When vacuum-dried at 20 ° C. for 20 hours, 3.6 g of a polymer was obtained.

When the intrinsic viscosity was measured at 30 ° C. in perfluoro (2-butyltetrahydrofuran), it was 0.69.
It was dl / g. A film was obtained from this polymer by press molding at 230 ° C. The refractive index of this film was 1.32 when measured using an Abbe refractometer. When Tg was measured by viscoelasticity measurement, 142 ° C
Met. The 10% weight loss temperature of this copolymer was 436 ° C. as determined by thermogravimetric analysis in air.

Example 3 5.0 g of 2,3,5,5,6-pentafluoro-6-trifluoromethyl-1,4-dioxene, 5 g of perfluoro (2-butyltetrahydrofuran), ion-exchanged water 50 g and 0.02 g of bisisopropyl peroxydicarbonate as a polymerization initiator, the internal volume of 100 m
1 stainless steel autoclave. After deaeration of the system by freeze deaeration, pressure deaeration with N ₂ gas was repeated 3 times, and then tetrafluoroethylene was added at a gauge pressure of 2 kg / c.
introduced up to m ² . After holding at 40 ° C. for 48 hours, cooling, taking out the contents, washing with water, washing with methanol, and vacuum drying at 120 ° C. for 20 hours, 1.0
g of polymer was obtained. The intrinsic viscosity of this polymer was 0.28 dl / g at 30 ° C. in perfluoro (2-butyltetrahydrofuran). The refractive index of this polymer was 1.34.

[0036]

The fluoropolymer of the present invention is a solvent-soluble, transparent polymer having a high Tg. The present polymer is an amorphous, transparent and solvent-soluble polymer while having excellent properties as a perfluoropolymer, such as heat resistance and chemical stability. The effect that it can be made into an ultra-thin film without defects such as is recognized, and it can be applied to coating materials and separation membrane materials. Utilizing the low refractive index, it can be applied to optical materials such as antireflection agents and optical fiber cladding materials. Further, since the fluorine-containing polymer according to the present invention is a fluorine compound and thus has a low dielectric constant, the effect that it can be applied as an electronic material is also recognized.

The applications of the perfluoropolymer according to the present invention include wire coating materials, magnetic recording medium protective layers, gas selective permeable film materials, optical lenses, optical waveguides, artificial crystalline lenses,
Low reflection processing agent, safety glass laminated material, optical element adhesive,
Solar cell light intake surface material, color filter protective film, flux creeping-up prevention agent, release agent, semiconductor protective layer, aircraft window material, mirror surface coating material, mirror substrate, fishing line, semiconductor carrier, pellicle protective film Materials, electrophotographic photoreceptor surface layer, non-linear optical element, photochromic molding material base material, filter material, electrophoretic support, photoreactor, bioreactor,
Examples include UV lamps.

Claims (2)

[Claims] 1. A repeating unit represented by the general formula (A) (wherein R is fluorine or a perfluoroalkyl group having 1 to 10 carbon atoms), and the repeating unit is in perfluoro (2-butyltetrahydrofuran) at 30 ° C. The measured intrinsic viscosity is 0.1
Fluorine-containing polymer having an amount of up to 5.0 dl / g. [Chemical 1] 2. The fluoropolymer according to claim 1, wherein the repeating unit represented by the general formula (A) accounts for 1 to 100 mol% of all repeating units.