JP3272474B2 - Method for producing ethylene-tetrafluoroethylene copolymer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an ethylene - tetrafluoroethylene copolymer (hereinafter, abbreviated as ETFE) relates to a novel method for producing, details by using a specific polymerization medium and a chain transfer agent, heat resistance The present invention relates to a method for efficiently producing ETFE having good solvent resistance, chemical resistance and the like.

[0002]

2. Description of the Related Art Since ETFE is a polymer material excellent in heat resistance, solvent resistance, chemical resistance, etc., it is utilized for various applications by utilizing its characteristics.

[0003] As a method for producing ETFE, a solution polymerization method, a suspension polymerization method, and an emulsion polymerization method are known. As a polymerization medium for the solution polymerization method and the suspension polymerization method, an inert solvent such as chlorofluorocarbon is used. It is usually used because it gives a high molecular weight copolymer and has a high polymerization rate. Specific examples of the chlorofluorocarbons, trichlorofluoromethane, dichlorodifluoromethane, trichlorotrifluoroethane, although such dichlorotetrafluoroethane is Ru and the like, trichlorotrifluoroethane has been mainly used from the handling point.

However, in the case of using chlorofluorocarbon as represented by said trichlorotrifluoroethane as the polymerization medium at the time of ETFE production, small but although chlorofluorocarbons, react with port Rimmer growing end radicals, the polymer molecule chains E with chlorine bonded to the end
TFE is generated . The carbon at the end of the polymer molecular chain
Chlorine bond, fried thermal stability adversely, thereby to color the ETFE when left for a long time at high temperature. In addition , such E
With TFE as wire coating material, a chlorine-containing polymer ends is decomposed during overmolding, it rises to corrosion of the core wire.

[0005] as the polymerization medium of full Tsu Motokei polymer during production
The perfluorocarbon such as perfluorohexane is known. As the chain transfer agent to produce thermal stability and moldability excellent fluoropolymer, meta
Nord is Ru through regular Irare Tei. However, if the path over fluorocarbon prepare a polymerization medium, the polymerization was carried out with methanol as a chain transfer agent, perfluorocarbon and methanol
It is very difficult to obtain a polymer of the intended molecular weight because of poor compatibility with

When perfluorocarbon is used as a polymerization solvent , an expensive fluorine-containing organic peroxide is usually used as a polymerization initiator . However, fluorine-containing organic peroxides
When producing the ETFE with oxide, perfluoro-copolymer, for example tetrafluoroethylene - as compared with the case of producing a perfluoro (propyl vinyl ether) copolymer, poor initiation efficiency of the polymerization initiator, the polymerization Initiator
The will be used in a large amount, is economically disadvantageous.

[0007]

[SUMMARY OF THE INVENTION The present invention does not produce ETFE chlorine at the end of port Rimmer molecular chains are bonded, heat resistance, solvent resistance, efficiently ETFE excellent in chemical resistance economically It is intended to provide a method of manufacturing.

[0008]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to achieve the above object, and as a result, have obtained a polymerized medium.
It has been found that the object can be achieved by using a specific hydrofluorocarbon and using an alcohol such as methanol as a chain transfer agent.

That is, the present invention relates to a method for preparing a chain in a polymerization medium.
Under the addition of transfer agents, capable of being polymerized using a polymerization initiator
In ETFE manufacturing method consisting of the polymerization medium, and a fluorine atom and a hydrofluorocarbon having 3 to 10 carbon atoms containing one or more and fluorine atoms and the same number or less of the hydrogen atom, Ru chain transfer agent alcohols der it is a manufacturing method of E TFE you characterized.

In the present invention, usually , the molar ratio of tetrafluoroethylene (TFE) / ethylene charged is 30.
/ 70-95 / 5 in the range <br/> particularly 40 / 60-90 / 10, in the hydrofluorocarbon, by copolymerizing TFE and ethylene, can be produced ETFE.

Further, a small amount of a comonomer other than TFE and ethylene may be further copolymerized. These comonomers CF ₂ = CFCl, fluoro ethylenes such as CF ₂ = CH _2, hexafluoropropylene such as _{CF 2 = CFCF 3, CF 2} = CHCF 3, CF 3 CF 2 CF 2 CF 2 CH =
( Perfluoroalkyl ) ethylenes having 4 to 12 carbon atoms in perfluoroalkyl groups such as CH ₂ and CF ₃ CF ₂ CF ₂ CF ₂ CF CH ₂ , and R ^f (OCFXCF ₂ ) _m OCF
= CF ₂ (formula in ^the R ^f perfluoroalkyl group having 1 to 6 carbon atoms, X is a fluorine atom or a trifluoromethyl group, m represents an integer of 1 to 5.) Perfluoro vinyl ethers such as, CH ₃ OC (= O) CF ₂ CF ₂ CF ₂ OCF = C
F ₂ or _{FSO 2 CF 2 CF 2 OCF (} CF 3) CF 2 OCF =
Perfluorovinylethers with readily carboxylic acid group or a sulfonic acid group can be converted into a group such as CF _2, propylene, olefins such as isobutylene like et al
It is. Comonomer used alone or in combination of two or more
You can also .

The copolymerization ratio of these comonomers is usually E
It is desirable that the amount of TFE is 30 mol% or less, particularly about 0.1 to 15 mol%, based on the total monomer units .

[0013] The polymerization medium used in the present invention, fluorine atoms and one or more on or One fluorine atoms and the same number or less of the hydrogen
Hydrofluorocarbon having 3 to 10 carbon atoms including atoms
It is. If the number of carbon atoms is 2 or less, the boiling point is too low and the polymerization pressure rises, and if it is 11 or more, the boiling point is too high ,
It becomes difficult to separate ETFE from the polymerization medium after polymerization, which is disadvantageous in production. When the hydrogen atom no single, can not use methanol as a chain transfer agent as described above. Further, the hydrogen atom number greater than the number of fluorine atoms are present, since the hydrogen atoms is a chain transfer point, the polymerization
Not desirable as a medium .

[0014] Particularly preferred polymerization _{medium, C 4 F 4 H 4,} C 4
_{F 8 H 2, C 5 F} 11 H, C 5 F 10 H 2, C 6 F 13 H, C 6 F 12
H ₂ or C ₆ F ₉ H ₅ , specifically 1,1,2,2-
Tetrafluorocyclobutane, CF ₂ HCF ₂ CF ₂ CF ₂
H, CF ₃ CFHCF ₂ CF ₂ CF ₃ , CF ₃ CF ₂ CF ₂ C
F ₂ CF ₂ H, CF ₃ CF ₂ CFHCF ₂ CF ₃ , CF ₃ CF
HCFHCF ₂ CF ₃ , CF ₂ HCF ₂ CF ₂ CF ₂ CF
₂ H, CF ₂ HCFHCF ₂ CF ₂ CF ₃ , CF ₃ CF ₂ CF ₂
CF ₂ CF ₂ CF ₂ H, CF ₃ CH (CF ₃ ) CF ₂ CF ₂ C
F ₃ , CF ₃ CF (CF ₃ ) CFHCF ₂ CF ₃ , CF ₃ CF
(CF ₃ ) CFHCFHCF ₃ , CF ₃ CH (CF ₃ ) CF
HCF ₂ CF ₃ , CF ₂ HCF ₂ CF ₂ CF ₂ CF ₂ CF ₂ H,
CF ₃ CF ₂ CF ₂ CF ₂ CH ₂ CH ₃ .

In the present invention, as the polymerization medium , the above-mentioned hydrofluorocarbon may be used by containing an inert solvent such as water. The amount of the polymerization medium, but it is capable to change the type of the monomers to be polymerized, on the quality of the whole monomer, 3-100 times, preferably 5-50 times is there.

In the present invention, any of a solution polymerization method and a suspension polymerization method can be employed as the polymerization method. As the polymerization initiator to be used, fluorine-based or hydrocarbon-based organic peroxides and azo- based compounds can be used. However, hydrocarbon-based organic peroxides are not suitable for the thermal stability and economic efficiency of ETFE. Is preferred.

[0017] As organic peroxides of the hydrocarbon containing, for example, acetyl peroxide Oki shea de, Isobuchirirupa <br/> Oki shea Jiashirupaoki sheet de such as de, diisopropyl peroxydicarbonate, di -n- propyl peroxydicarbonate Peroxydicarbonate such as dicarbonate, t
-Butylperoxyisobutyrate, t-butylperoxypivalate, t-butylperoxy-3,5,5-
And peroxyesters such as trimethylhexanoate.

[0018] The amount of the polymerization initiator, species <br/> such polymerization initiators, depending on the copolymerization reaction conditions may be appropriately modified, with respect to the total normal heavy engaged thereby to monomer And 0.00
5-5 mass%, particularly about 0.05 to 0.5 mass% is employed.

[0019] In the polymerization in the present invention, it is added pressure to the chain transfer agent for the purpose of controlling the molecular weight of ETFE. As chain transfer agents , methanol, ethanol, n
- propanol, iso pro Piruaruko over but alcohols such as Le is used, it is particularly preferable to molecular weight using a small high thermal stability methanol. The use of alcohol as a chain transfer agent, when molten molding, without wearing <br/> color, less die swell, i.e. heat resistance, moldability
It is possible to obtain an excellent ETFE to. The amount of alcohols added depends on the type of polymerization and polymerization reaction conditions,
About 0.01 to 50 mass% with respect to the polymerization medium may be employed.

[0020] on the occasion on Polymerization of the present invention, Ru is employed without polymerization <br/> condition a wide range is particularly limited. For example, heavy
Degree if temperature, the optimum value of selected depending on the kind of the polymerization initiator
It is, but is usually about 0 to 100 ° C., particularly about 30 to 90 ° C. are employed. The polymerization pressure can also be appropriately selected, but is usually ^{2 to} 100 kg / cm ² , particularly 5 to 20 kg.
/ Cm ² is preferably employed. In the present invention, than it may advantageously perform polymerization without requiring polymerization pressure excessive, Ru possible der adopting a higher pressure condition or reduced pressure condition. Further, the present invention is Ru are carried out by appropriately selecting operations such as batch or continuous type.

[0021]

Volume flow rate in EXAMPLES In the examples, the high reduction type flow tester, the temperature 300 ° C., the inner diameter 1 at a load of 30kg
It measures the capacity (mm ³ ) per unit time (second) of the polymer flowing out from a nozzle having a land length of 2 mm and a length of 2 mm.

[0022] Example 1 was deaerated stainless steel reaction vessel having an inner volume of 1.2 liters, the _{CF 3 CF 2 CF 2 CF 2} CH 2 CH 3 as the polymerization medium 1350 g of methanol as a chain transfer agent 1. 8 g, then 85 g of TFE and 5.9 g of ethylene
Was charged. The temperature was maintained at 65 ° C., and 1,3-dichloro-1,1,2,2,3 was used as a polymerization initiator and as a solvent.
-Pentafluoropropane (hereinafter referred to as R-225cb)
U. ) Was charged with 10 mass% soluble solution of 3ml of t- butyl peroxy isobutyrate using to initiate the reaction. During the reaction, a mixed gas of TFE and ethylene (molar ratio , TFE / ethylene = 53/47 ) was introduced into the system, and the reaction pressure was maintained at 13.5 kg / cm ² .

The white copolymer 85g was obtained in a slurry state after 3 hours. The copolymer had a melting point of 278 ° C., a starting point of thermal decomposition of 360 ° C., and a volume flow rate of 53. At a molding temperature of 300 ° C., a good compression molded product without coloring was obtained. Molded product
Has a tensile strength of 428 kg / cm ² and a tensile elongation of 440%.
Met. Even resulting molded article was held for 3 days at 250 ° C., coloration was not Donna photons. Inside diameter 1.0 at 300 ° C
extrusion speed of 36 mm using a 10.0 mm long die.
Die swell when extruded at 0 mm / min is 1.15
Met.

[0024] Example 2 was deaerated stainless steel reaction vessel having an inner volume of 1.2 liters, CF ₃ CF (CF ₃₎ as the polymerization medium CFHCFHC
F ₃ of 550 g, demineralized water 700 g, were charged 75g of methanol as a chain transfer agent, then 45 of TFE
g, was charged ethylene 3.7 g, the 0.8g of (perfluorobutyl) ethylene. Keep the temperature at 50 ° C,
As a polymerization initiator to initiate the charged reaction 3ml of 10 mass% solution of diisopropyl <br/> propyl peroxydicarbonate in which the R-225cb and solvent.

During the reaction, a mixed gas of TFE and ethylene (molar ratio , TFE / ethylene = 53/47 ) was introduced into the system, and the reaction pressure was maintained at 17.5 kg / cm ² . White copolymer 55g after 6 hours was obtained in a slurry state. The copolymer had a melting point of 269 ° C. and a thermal decomposition starting point of 345.
C. and a volume flow rate of 62, and a good compression molded product without coloring was obtained at a molding temperature of 300.degree. The tensile strength of the molded product is 4
00 kg / cm ² and tensile elongation were 490%. Even if the obtained molded product is kept at 250 ° C. for 3 days, coloring is almost impossible.
It was bought Donna. The die swell when extruded as in Example 1 was 1.20.

[0026] [Example 3] Polymerization initiator, 3ml of 5 mass% soluble liquid perfluoro butyryl peroxide Oki sheet de where the R-225cb with solvent
Except for using the polymerization was carried out in the same manner as in Example 1.
During the reaction, the progress of polymerization is slowed down ,
The 1ml of polymerization initiator solution quickened charged polymerization reaction rate. The polymerization initiator solution the total 10ml were charged, copolymers of 80g was obtained by the slurry state after 3 hours.

The copolymer had a melting point of 275 ° C., an onset of thermal decomposition of 365 ° C., and a volume flow rate of 32. At a molding temperature of 300 ° C., a good compression molded product without coloring was obtained. The molded article had a tensile strength of 460 kg / cm ² and a tensile elongation of 480%. Even resulting molded article was held for 3 days at 250 ° C. coloration was not Donna photons. The die swell when extruded as in Example 1 was 1.15.

[0028] [Example 4] polymerization medium, 13 of CF ₃ CF ₂ CFHCFHCF ₃
Except for using 00g is Polymerization was carried out in the same manner as in Example 1. After 2.5 hours the white copolymer 90g was obtained in a slurry state. However, CF ₃ CF ₂ CFHCFH
CF ₃ converts TFE and hexafluoropropylene into AlC
adduct obtained by addition using l ₃ / CFCl ₃ as a catalyst
And a compound obtained by hydrogenation using a Pd / C catalyst
It is.

The copolymer had a melting point of 276.degree. C., a thermal decomposition starting point of 365.degree. C., and a volume flow rate of 41. At a molding temperature of 300.degree. The molded article had a tensile strength of 465 kg / cm ² and a tensile elongation of 480%. Even resulting molded article was held for 3 days at 250 ° C. coloration was not Donna photons. The die swell when extruded as in Example 1 was 1.14.

[0030] [Comparative Example 1] polymerization medium, except for using 1200g of 1,1,2-trichlorotrifluoroethane to obtain a copolymer of 90g in the same manner as in Example 1. The copolymer has a melting point of 2
76 ° C., pyrolysis start point 357 ° C., volumetric flow rate 58,
At a molding temperature of 300 ° C., a good compression molded product without coloring was obtained. The molded article had a tensile strength of 445 kg / cm ² and a tensile elongation of 420%. The obtained molded product is heated at 250 ° C. for 3 hours.
When kept for days, it turned brown. The die swell when extruded as in Example 1 was 1.17.

[0031] [Comparative Example 2] Polymerization medium, except for using 700g of hexane, were subjected to polymerization in the same manner as in Example 1, polymerization hardly proceeded.

[0032]

According to the present invention does not produce the ETFE of chlorine at the end of port Rimmer molecular chains are bound. Further , ETFE having excellent heat resistance, solvent resistance and chemical resistance can be economically and efficiently produced.

──────────────────────────────────────────────────続 き Continuation of front page (72) Inventor Haruhisa Miyake 1150 Hazawa-cho, Kanagawa-ku, Yokohama-shi, Kanagawa Prefecture Asahi Glass Co., Ltd. Examiner at Central Research Laboratory Masahiro Shibata (56) JP-A-3-243607 (JP, A) JP-A-3-17106 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08F 2/04-2/06 C08F 2/38 C08F 210/00-210/02 C08F 214/26

Claims (3)

(57) [Claims] (1) In a polymerization medium, with the addition of a chain transfer agent,
The method of manufacturing a tetrafluoroethylene copolymer, - ethylene which comprises polymerizing by using a polymerization initiator
Polymerization medium, a hydrofluorocarbon having 3 to 10 carbon atoms containing fluorine atoms and one or more and fluorine atoms and the same number or less of the hydrogen atoms, to the chain transfer agent, wherein the alcohol der <br/> Rukoto Rue styrene - tetrafluoroethylene
A method for producing a copolymer. 2. The method according to claim 1, wherein the alcohol is methanol.
The production method described in 1. 3. A process according polymerization initiator to claim 1 or 2 Ru organic peroxide der of hydrocarbon type.