JPS63238111A - Production of fluorine-containing polymer having cyclic structure - Google Patents

Abstract

PURPOSE:To obtain the titled amorphous, transparent and solvent-soluble polymer having excellent heat resistance, etc., by radically polymerizing a specific perfluoro ether having two terminal double bonds and forming a polymer having a ring structure in the backbone chain. CONSTITUTION:(A) A perfluoro ether, expressed by formula I (n is 0-5; m is 0-5 and n+m is 1-6) and having two terminal double bonds is radically polymerized to form (B) a polymer having a ring structure expressed by formula II in the polymer backbone and afford the aimed polymer. Furthermore, a perfluoroallyl vinyl ether expressed by formula III is preferred as the component (A).

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a method for producing a fluoropolymer having a cyclic structure, and more specifically, the present invention relates to a method for producing a fluoropolymer having a cyclic structure, and more specifically, the present invention relates to a method for producing a fluoropolymer having a cyclic structure. The present invention relates to a new method for producing a fluoropolymer having a ring structure in the polymer main chain, which involves radical polymerization.

[Prior Art] Various fluoropolymers have been known so far, and many of them, including polytetrafluoroethylene, are in industrial use. However, these are mostly polymers with linear main chains based on vinyl monomers such as fluoroolefins or (meth)acrylates having fluoroalkyl groups in the side chains. Alternatively, polymer compounds such as perfluoropolyether obtained by ring-opening polymerization of hexafluoropropylene oxide are also known, but in this case, the main chain structure is also linear using a tungsten or molybdenum catalyst. Attempts have been made to synthesize the compound by ring-opening metathesis polymerization (A, Alimuniare et al.
, Polymar, 1986271281), these are all ordinary vinyl polymerization, ring-opening, or ring-opening metathesis polymerization, and do not introduce a ring structure into the main chain by ring-closing polymerization from a linear monomer.

Slightly, the general formula CF2-CF(CF2)x CF-CF
2 (where X is 1 to 5) is known to be cyclized and polymerized by γ-rays (L, A, Waal, Fl
uor.

PolyIIler, Wiley-Science,
4. High Pressure Polymeri
zation, P, 12? ), also CF2-CF-
It is known that Ch -CFCI-Ch-CFICF2 polymerizes to give a transparent, strong elastic film with excellent heat resistance and oxidation resistance (D, S, Ba1lenti
ne atat,, U, S, Atomic Ener
gy Cotas, B, ML-294 (T-50) 18
．． However, these are all high-pressure polymerization methods that require high pressures of 10,000 atm or more, and have the disadvantage that they are difficult to implement industrially.

Furthermore, British Patent No. 110111344, U.S. Patent No. 3418302, etc. have CF2-0F-0-CF
A method is described in which perfluorodimethylene bis(perfluorovinyl ether) z-CF2-0-CF-CF2 is cyclized and polymerized as a monomer. However, this polymerization method is limited in that cyclization polymerization can only be carried out under dilute conditions where the monomer concentration is 12% by weight or less. It is stated that a polymer is produced when the monomer concentration is 12% or more. The fact that the monomer concentration must be below 12% is disadvantageous for industrial practice, since large amounts of diluting solvent must be used.

[Problems to be Solved by the Invention] According to the research of the present inventors, regarding fluoropolymers, particularly perfluoropolymers, it has been found that it is possible to industrially smoothly convert linear monomers into polymers having a ring structure in the main chain. As mentioned above, there are almost no known means for producing it advantageously, and in cyclization polymerization using a heptamer such as the above-mentioned perfluorodimethylene bis(perfluorovinyl ether). In addition to the limitation of polymerization under large dilution conditions as mentioned above, there is also the drawback of gelation as a by-product in the polymerization reaction system.

Based on the recognition of the above-mentioned problems, the present inventor conducted intensive research and study on the production of fluorine-containing polymers having a ring structure in the main chain, and as a result, adopted a specific hexamer such as perfluoroallyl vinyl ether. Surprisingly, it has been discovered that by radical polymerization, it is possible to smoothly and advantageously produce the desired fluoropolymer by suppressing gelation by-products, without using ultra-high pressure conditions or large dilution conditions. I came across this.

[Means for Solving the Problems] Thus, the present invention has been completed based on the above-mentioned new findings, and is based on the general formula CF2□CFal:Fz)n
O(CFz)scF-Ch (where n is 0 to 5.
m is 0 to 5, and n+m is 1 to 13) A perfluoroether having two terminal double bonds is radically polymerized to produce a polymer having a ring structure in the polymer main chain. The present invention provides a novel method for producing a fluoropolymer having a cyclic structure.

In the present invention, it is important to use specific perfluoroethers, for example CF2-0F-0-C
A fluorine-containing polymer having a ring structure such as that obtained by radical polymerization of Fz-OF-CF2 can be produced smoothly and advantageously.

In the above general formula, n and m4 are each integers of 0 to 5, and n+m1 is an integer selected from a combination of 1 to B. Preferably, n and m are each integers of 0 to 3, and rl+Il is 1 to 4. More preferably, n and 11 are each integers of 0 to 2, and n+m is 1 to 3.

As the above-mentioned specific perfluoroether, perfluoroallyl vinyl ether (CF2=cFOchcF-C
F2), perfluorodiallyl vinyl ether (C;F
2-CFCh OCh CFegGFz), perfluorobutenyl vinyl ether (CF2 = CFOCF2
CF2CF=CF2), barfluorobutenyl allyl vinyl ether CCh-CFChOCF20F20F
=CF2), perfluorodibutenyl vinyl ether (
CF2-GFIL:F2CF200F2C:F2CF=
CFz), but in the present invention, n,
One of m is O, that is, Ch-CFO-
Those with one vinyl ether group have polymerization reactivity,
It is preferably adopted in terms of ring-closing polymerizability and gelation suppression,
In particular, perfluoroallyl vinyl ether (CF2-CF
OCF20F-CF2) is mentioned as a suitable example.

It was surprisingly discovered that such a specific perfluoroether polymerizes under relatively mild conditions to give a polymer having a cyclic structure in its main chain, which led to the present invention. That is, the polymerization method is not particularly limited as long as it proceeds in a radical manner, and examples thereof include polymerization using an organic or inorganic radical initiator, light, ionizing radiation, or heat. As the radical initiator, 2,2'-azobis(N,N'-dimethyleneisobutyramidine) dihydrochloride, 2,2'-azobis(2-amidinopropane) dihydrochloride,
2,2'-azobis(N,N'-dimethylenebutyramidine), 4,4'-azobis(4-cyanopentanoic acid'), 2,2'-azobis(2-methyl-N-[ 1,1-bis(hydroxymethyl)-2-
hydroxyethylcobropionamide), 2.2'
-Azobis(2-methyl-N-[1,1-bis(hydroxymethyl)ethyl]propionamide), 2.2
'-Azobis[2-methyl-N-(2-hydroxyethyl)propionamide], 2,2'-azobis(isobutyramide) cibidelate, 2,2'-azobis(4-methoxy-2,4-dimethylvalero) Nitrile)
, 2.2'-azobis(2,4-dimethylvaleronitrile), (1-phenylethyl)azodiphenylmethane, 2.2'-azobisinbutyronitrile, dimethyl 2
．． 2'-azobisisobutyrate, 2,2'-azobis(2-methylbutyronitrile), 1.1'-azobis(1-cyclohexanecarbonitrile), 2-(carbamoylazo)-inbutyronitrile, Azo compounds such as 2,2'-azobis(2,4,4-trimethylpentane), 2-phenylazo-2,4-dimethyl-4-methoxyvaleronitrile, 2,2'-azobis(2-methylpropane), Stearoyl peroxide, diisobrobyl peroxide, benzoyl peroxide, 2,4-dichlorobenzoyl peroxide, acetyl peroxide, t-butyl hydroperoxide, cumene hydroperoxide, di-isopropylbenzene hydroperoxide , para-menthane hydroperoxide, 2,5-dimethylhexane-2,5-cybidroba-oxide, methyl ethyl ketone peroxide, cyclohexanone peroxide, di-t-butyl peroxide, dicumyl peroxide, t-butylcumyl peroxide , 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, 2,5-dimethyl-2,5-di(1
-butylperoxy)hexyne-3, octanoyl peroxide, decanoyl peroxide, lauroyl peroxide, t-butyl perbenzoate, t-butyl peracetate, t-butyl perpivalate, t-butyl perisobutyrate, t-Butylperoxyisobrobyl carbonate, di-t-butylshiba-phthalate, t-
Butyl perlaurate, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, diperfluorobutanoic peroxide, diperfluoro-3-oxa-2-methylhexanoic peroxide , organic peroxides such as Jeeperfluorononanoic peroxide, and inorganic peroxides such as K2 S2 as and (NH4)2S20B. Examples of the light include visible light and ultraviolet light, and a photosensitizer can also be used in combination. As ionizing radiation, 6Gco, 192Ir
, 170Tffl, 1370s, etc., and electron beams from an electron beam accelerator.

The polymerization method is also not particularly limited, and includes so-called bulk polymerization in which monomers are directly subjected to polymerization, and fluorinated hydrocarbons, chlorinated hydrocarbons, fluorinated hydrocarbons, alcohols, hydrocarbons, and other organic solvents in which monomers are dissolved. Examples include solution polymerization carried out in an aqueous medium, suspension polymerization carried out in the presence or absence of an appropriate organic solvent in an aqueous medium, and emulsion polymerization carried out by adding an emulsifier to an aqueous medium. is not particularly limited, but it is desirable to set it appropriately taking into consideration various factors such as the boiling point of the polymer, the required heating source, and the removal of heat of polymerization. For example, from 0°C to
A suitable temperature can be set between 200°C, and a practically suitable temperature can be set between room temperature and about 100°C. In addition, the polymerization pressure may be under reduced pressure or increased pressure, and practically, it is about normal pressure to 100 atmospheres,
Furthermore, suitable polymerization can be carried out at normal pressure to about 50 atmospheres.

Since the fluoropolymer obtained by the present invention has a ring structure in its main chain, it is an amorphous, transparent, and solvent-soluble polymer, but has high chemical stability and heat resistance. We are prepared. It also has a low refractive index, high light transmittance, and high He selective transmittance. Furthermore, the fluoropolymer of the present invention can achieve an ultra-thin film without defects such as pinholes, which has been difficult to achieve with conventional fluoropolymers. Specific application fields in which the fluoropolymer of the present invention is useful due to these properties include, for example, transparent coating materials, paint materials, insulation film materials,
Examples include materials for weather-resistant films, optical materials, and materials for separation membranes.

[Function] In the present invention, the mechanism by which use of a specific perfluoroether eliminates the need for ultra-high pressure conditions or high dilution conditions for cyclization polymerization is not necessarily clear, but C
Since the -0-C bond is flexible, it is thought that the two double bonds can easily approach each other within the molecule, allowing cyclopolymerization to proceed even under low pressure. It is thought that this makes it easier to cause some kind of difference in the reactivity of the two double bonds, making it possible to suppress gelation by-products during the polymerization reaction without adopting high dilution conditions. It should be noted that this explanation is provided to assist in understanding the present invention, and is not intended to limit the present invention in any way.

[Examples] Next, Examples of the present invention will be described in more detail, but it goes without saying that the present invention is not limited by such explanations.

Example 1 30 g of perfluoroallyl vinyl ether and a polymerization initiator diisoprobyl peroxydicarbonate (hereinafter referred to as
0.3g of (abbreviated as IFF)! I put it in a 0Qcc glass Kolben. As a result of zero polymerization, in which the pressure during zero polymerization was lower than atmospheric pressure, in which polymerization was carried out at 25° C. for 16 hours after the freeze degassing was repeated twice, 4.5 g of a polymer was obtained.

When we measured the infrared absorption spectrum of this polymer, we found that
1790c++r due to double bond in monomer
There was no absorption near l. Further, when this polymer was dissolved in perfluorobenzene and a +91i(7) NMR spectrum was measured, a spectrum showing the following repeating structure was obtained.

The intrinsic viscosity [η] of this polymer is Fluorinert FC-7
5 (Product name: Liquid whose main component is perfluoro(2-butyltetrahydrofuran) manufactured by 3M Company, hereinafter referred to as FC-
75) at 30°C, indicating a high degree of polymerization.

The glass transition point of the polymer is 63°C, and it is a tough, transparent, glass-like polymer at room temperature. Furthermore, the 10% thermal decomposition temperature was 482°C, indicating high thermal stability. Furthermore, this polymer was colorless and transparent, had a low refractive index of 1.34, and a high light transmittance of 85%.

The permeability coefficients of various gases of this polymer were measured. The measurement results and transmission coefficient ratios are shown below.

Example 2 10 g of perfluoroallyl vinyl ether, 10 g of dolchlorotrifluoroethane, and 1 g of polymerization initiator IFF
0 mg was placed in a 50 cc glass Kolben. The pressure during zero polymerization, which was polymerized at 40° C. for 14 hours after repeating freeze degassing twice, was lower than atmospheric pressure. As a result of polymerization, 1.1 g of 1 polymer was obtained.

The intrinsic viscosity [η] of this polymer is 0 at 30°C in FC-75.
．． 37, indicating that it was a high molecular weight polymer.

The obtained polymer was found to be the same polymer as in Example 1 from the 19F NMR spectrum.

Example 3 30 g of perfluoroallyl vinyl ether and 10 mg of a polymerization initiator (C3F7CO)2 were placed in a 50 cc glass colben. 30℃ after repeating freezing and degassing twice
As a result of the 0 polymerization, in which the pressure during the 0 polymerization was lower than atmospheric pressure for 16 hours, 18 g of polymer was obtained.

The intrinsic viscosity [η] of this polymer was 0.505 at 30°C in FC-75.

[Effects of the Invention] The present invention has an excellent effect in that by employing a specific perfluoroether monomer, a fluoropolymer having a ring structure in the polymer main chain can be produced smoothly and advantageously. It has the effect of achieving cyclization polymerization from linear monomers without employing ultra-high pressure conditions or high dilution conditions. In addition, the fluoropolymer having a ring structure in the main chain obtained by the present invention has excellent properties as a fluoropolymer, such as heat resistance and chemical stability, and is also amorphous, transparent, and solvent free. It is a soluble polymer. Due to these characteristics, the fluoropolymer of the present invention has been recognized to have the effect of being able to be made into an ultra-thin film without defects such as pinholes, and has the potential to expand the range of applications to optical materials, coating materials, separation membrane materials, etc. There are also advantages.

Claims (1)

[Claims] 1. General formula CF_2=CF-(CF_2)-_nO-(
CF_2) -_mCF=CF_2 (where n is 0 to 5
, m is 0 to 5, and n+m is 1 to 6) is radically polymerized to produce a polymer having a ring structure in the polymer main chain. A method for producing a fluoropolymer having a cyclic structure, characterized in that: 2. Perfluoroether is CF_2=CF-O-CF
_2-CF=CF_2 perfluoroallyl vinyl ether, the manufacturing method according to claim 1.