JPH0762087A - Oxidized polymer of fluorinated butadiene, its production method and use - Google Patents

Abstract

(57) [Summary] [Structure] The following formulas (I), (II) and (III): (In the formula, X represents F, H, Cl or CF ₃ , at least one is F, and x, y and z are 1 <x + y ≦ 10,000.
It is a positive integer satisfying the conditions of 0, 1 ≦ z ≦ 10,000, and x + y ≧ z. ) A novel fluorinated butadiene oxide polymer having a structural unit represented by The polymer is obtained by copolymerizing fluorinated butadiene and oxygen. [Effect] The polymer can be used as a radical polymerization initiator, a cross-linking agent for fluororubber, and the like.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel fluorinated butadiene oxidative polymer, a process for producing the same, and a radical polymerization initiator and a rubber cross-linking agent for its use.

[0002]

2. Description of the Related Art Plunket of 1938
Since the invention of polytetrafluoroethylene by Dr. t), various fluorinated butadiene polymers have been tried to be used as fluororubbers in view of the development of SBR and NBR rubbers. However, the introduction of fluorine atoms into butadiene
In some cases, not only the polymerization reactivity becomes difficult, but also the glass transition temperature of the produced polymer is high, which is not always successful as a rubber. As a resinous material, recently, perfluorobutadiene is a soft anionic polymerization catalyst such as Cs.
F, anionically polymerized by _{Al (O-tBu) 3,} Zn (C 2 H 5) 2 or the like, it is known to provide a high polymer. For the synthesis and polymerization of fluorinated butadienes
l), example by Tarrant [Journal
Of the American Chemical Society (JAC.
S.), 77, 3640 (1955)] and British Patent No. 856,469, and the latter shows an example using a Ziegler-Natta type catalyst. However, these references do not give any suggestion on the formation of fluorinated butadiene oxidative polymers. Meanwhile butadiene presence of _{(CH 2 = CH-CH =} CH 2) radical source, to provide a relatively high temperature oxide polymer has been elucidated by, for example, Dale (Dale), etc. [Industrial and Engineering Chemistry, Product Research and Development (I &
EC, Product Research and Development) Volume 7,
No 2, pp. 136-151 (1968)].

[0003]

DISCLOSURE OF THE INVENTION The present invention is intended to provide an oxidative polymer of fluorinated butadiene, a method for producing the same, and a radical polymerization initiator and a rubber cross-linking agent for its use.

[0004]

Means for Solving the Problems The present inventor spontaneously polymerized butadiene pentafluoride (CF ₂ ═CF—CH═CF ₂ ) in a cold trap at −70 ° C. A polymer was obtained. The polymer was mainly in the 1,2-addition type according to the infrared absorption spectrum and was rubbery at -40 ° C. While studying this polymerization mechanism, the present inventor has found that fluorinated butadienes copolymerize with oxygen very easily, and has completed the present invention. That is, the first gist of the present invention is the following formulas (I), (II) and (III):

[Chemical 3] (In the formula, X represents F, H, Cl or CF ₃ , at least one is F, and x, y and z are 1 <x + y ≦ 10,000.
It is a positive integer that satisfies the conditions of 0, 1 ≦ z ≦ 10,000, and x + y ≧ z. The gist is an oxide polymer of fluorinated butadiene having a structural unit represented by the formula (1).

A second aspect of the present invention is a method for producing the above-mentioned oxidation polymer, that is, the following formula:

[Chemical 4] Characterized in that fluorinated butadiene represented by the formula (wherein X is as defined above) is copolymerized with oxygen in the presence or absence of a radical source (excluding oxygen), This is a method for producing an oxidative polymer of fluorinated butadiene. A third aspect of the present invention is a radical polymerization initiator characterized by comprising the above-mentioned oxidized polymer. A fourth gist of the present invention is a cross-linking agent comprising the above-mentioned oxidized polymer. The present invention will be described in detail below.

Examples of fluorinated butadiene used in the present invention include pentafluorobutadiene, trifluorobutadiene, fluoroprene, tetrafluorobutadiene, hexafluorobutadiene and 2-trifluoromethylbutadiene. Among the most preferred are pentafluoride butadiene _{(CF 2 = CF-CH =} CF 2). Butadiene pentafluoride can be obtained, for example, by the following steps.

[Chemical 5] Trifluorobutadiene can be obtained, for example, by the following steps.

[Chemical 6] Further, hexafluorobutadiene can be obtained, for example, by the following steps.

[Chemical 7]

The oxidative polymerization of the present invention (copolymerization with oxygen in the presence or absence of a radical source (excluding oxygen)) can be achieved, for example, by allowing liquid fluorinated butadiene to coexist with oxygen. If necessary, a method of blowing oxygen or a gas containing oxygen (for example, air) into the liquid fluorinated butadiene while stirring can also be adopted. The molar ratio of fluorinated butadiene and oxygen is 1/100 to 10,000 / 1.

Trichlorotrifluoroethane, perfluorobenzene, perfluorohexane or the like can be used as a diluent in the reaction system as a fluorine-based solvent. Further, as a molecular weight regulator, I (CF ₂ ) ₄ I, CCl
₄ I, (CH ₃ ) ₂ CHCH ₃ , C ₂ H ₅ SH, RfI (Rf is a perfluoroalkyl group) and the like are subjected to oxidative polymerization in the presence of an iodine compound, and the oxidation of the present invention in which iodine is bound to the molecular end It is also possible to obtain a polymer. The iodine transfer polymerization method of polymerizing a fluorine-containing monomer in the presence of an iodine compound is described in detail in Kogaku Shinbun, Vol. 49, No. 10, pp. 765-783.

In the oxidative polymerization of the present invention, it is not necessary to use a radical initiator, but peroxides may be used in some cases. Irradiation with ultraviolet light is also effective, but not essential. Polymerization temperature is -190 to 150
C, preferably -80 to 70 ° C, more preferably -70.
~ 30 ° C. It is a characteristic of fluorinated butadiene that it produces an oxidized polymer even at such a relatively low temperature.

The product is a rubbery polymer with a molecular weight of 500 to 500,000. In some cases, a crosslinked product is also obtained, and such a crosslinked product is insoluble in the above-mentioned solvents. The polymers obtained by the process of the present invention have the formulas (I), (II) and (III) as described above:

[Chemical 8] (In the formula, X represents F, H, Cl or CF ₃ , at least one is F, and x, y and z are 1 <x + y ≦ 10,000.
It is a positive integer that satisfies the conditions of 0, 1 ≦ z ≦ 10,000, and x + y ≧ z. ) Consists of structural units. In the present specification, x, y and z in the formulas (I), (II) and (III)
Is fluorinated butadiene 1,2 in the oxidation polymer of the present invention
It is a display for showing the numbers of adduct units, 1,4 adduct units and peroxide units. The ratio of the peroxide unit (z) to the fluorinated butadiene unit ((x) + (y)) can be adjusted by the oxygen supply concentration in the polymerization system, but when the oxygen concentration is high, x + y = z, that is, butadiene and oxygen. Tend to polymerize alternately. The oxidized polymer of the present invention tends to become rubbery as the oxygen content in the oxidized polymer increases.

The oxidative polymer of the present invention has a peroxide bond --O--O.
Since it has −, it is relatively stable at room temperature, but decomposes to generate radicals at room temperature or higher, particularly at a high temperature of 100 ° C. or higher. Therefore, it can be used as a radical polymerization initiator of a compound having an ethylenically unsaturated bond. Among these compounds, preferred are acrylic monomers,
Examples thereof include methacrylic monomers, fluorine-containing acrylic monomers, fluorine-containing olefin monomers, ethylene, vinyl chloride, styrene, vinyl acetate and acrylonitrile. The oxidized polymer of the present invention can also be used as a cross-linking agent used in a peroxide vulcanization reaction of rubber. Of the rubbers, the fluorine-containing rubber is particularly preferable because it has a high compatibility with the oxidation polymer of the present invention.

[0012]

EXAMPLES The present invention will now be described in detail with reference to Examples. Of course, the present invention is not limited to the examples.

Example 1 80 g of pentafluorobutadiene (CF ₂ ═CF—CH═CF ₂ ) was placed in a 200 ml glass container, and the head space was left in contact with air for 3 days at −78 ° C. The liquid pentafluorobutadiene changed into a rubbery gel. This gel is soluble in trichlorotrifluoroethane and acetone,
The IR spectrum of a film cast from this solution was determined by anionic polymer with CsF in the absence of oxygen.
FIG. 1 shows a comparison with (b) and a radical polymer (c) based on peroxide in the absence of oxygen. The ¹⁹ F NMR spectrum of the acetone solution of the polymer purified by reprecipitation with an acetone / methanol solvent is as shown in FIG. Elemental analysis value is C: 29.85%,
H: 0.93%, F: 54.0%, O: 15.2%, C
Corresponds to the composition of ₄ HF ₅ O ₂ . The presence of active oxygen was confirmed by iodometry. The polymer was rubbery even at -40 ° C. From the IR spectrum, 1,2 adduct, that is,

[Chemical 9] The structure of was estimated. The IR spectrum of the C = C double bond remaining in the polymer is shown in Figure 4 in comparison with that of the monomer and the radical copolymer with tetrafluoroethylene (TFE), vinylidene fluoride (VDF) and ethylene.

Example 2 A 200 ml flask was equipped with a dry ice type reflux condenser, a gas introduction tube and a thermometer, and 20 g of pentafluorobutadiene was introduced under magnetic stirring and condensed. Next, the flask temperature was brought to room temperature, and butadiene pentafluoride was refluxed. There was no change in the state where the air was cut off, but when the upper space of the reflux condenser was brought into contact with air, the polymer was deposited in the reflux condenser. This polymer was a resinous substance having a low oxygen content.

Example 3 As in Example 2, the introduction of pentafluorobutadiene was carried out, and then the reaction was carried out at −70 ° C. while positively blowing oxygen at a rate of 50 ml / min. Viscosity increased, and subsequently a white polymer was deposited. This polymer is partially soluble in trichlorotrifluoroethane.
A heating test was performed on the rubber-like material purified by reprecipitation with methanol. Table 1 shows the relationship between the treatment temperature / time and the weight loss rate, but it is clear that the polymer is decomposed. GPC measurement was carried out with a 1% tetrahydrofuran solution to measure the molecular weight, which was 3.1 × 10 ⁴ in terms of polystyrene. The results of measuring the change in the molecular weight of this solution when allowed to stand at room temperature are shown together with those of the sample obtained by the iodine transfer polymerization method (chain transfer agent: I (CF ₂ ) ₄ I, 0.5 g was added first) under the same conditions. As shown in FIG. From FIG. 3, a slight increase in the molecular weight was observed in the early stage, but thereafter, with the passage of time, a decrease in the molecular weight due to cleavage was observed. Polymerization occurred at room temperature when a small amount of this solution was added to methyl methacrylate.

[0016]

[Table 1]

Example 4 Instead of pentafluorobutadiene, trifluorobutadiene (CF ₂
= CF-CH = CH ₂ ) was used and polymerization was carried out in the same manner as in Example 3 to isolate the reaction product. Polymerization was much slower than pentafluorobutadiene. The IR spectrum is shown in FIG. In the case of butadiene trifluoride, the 1,4-addition type is predominant.

Example 5 Daier (registered trademark) G-901 (manufactured by Daikin Industries, Ltd.) known as a peroxide vulcanizable fluororubber
Example 3 with 4 parts triallyl isocyanurate in 100 parts
The rubber sheet obtained by adding 1 part of the rubber-like material obtained in step 1, roll-kneading under cooling, and press-molding for 30 minutes at 150 ° C. shows a strong elongation of 155 MPa and 560% at room temperature, and as a peroxide. Demonstrated the usefulness of.

[0019]

According to the present invention, a novel fluorinated butadiene oxidative polymer and a process for producing the same are provided. The oxidized polymer of the present invention is useful as a radical polymerization initiator, a rubber cross-linking agent, particularly a fluororubber cross-linking agent.

[Brief description of drawings]

FIG. 1 is an example of an IR spectrum of a pentafluorobutadiene polymer. (a) Oxidized polymer of Example 1, (b) homopolymer with CsF catalyst in the absence of oxygen, (c) homopolymer with peroxide in the absence of oxygen.

FIG. 2 is a ¹⁹ F NMR spectrum of the oxidized polymer of the present invention.

FIG. 3 shows the time course of GPC of a THF solution of an oxidized polymer of the present invention (after 0, 2, 18, 240 hours). ; A,
B is an oxidation polymer obtained in the absence of an iodine compound, C,
D is an oxidative polymer obtained by the iodine transfer polymerization method; A and C used a UV cell as a detector, and B and D used a RI cell.

FIG. 4 shows IR spectra of the double bond region of pentafluorobutadiene and trifluorobutadiene monomers and polymers. (a) to (d) are copolymers of pentafluorobutadiene, (a) is an oxidized polymer of the present invention polymerized at -78 ° C, and (b) is an oxidized polymer of the present invention polymerized at 25 ° C. (C) is a copolymer with vinylidene fluoride, (d) is a copolymer with tetrafluoroethylene or ethylene; (e) to (f)
Is a copolymer of trifluorinated butadiene, (e) is an oxide polymer of Example 4, and (f) is a copolymer with tetrafluoroethylene or ethylene.

Claims (4)

[Claims] 1. The following formulas (I), (II) and (II)
I): (In the formula, X represents F, H, Cl or CF ₃ , at least one is F, and x, y and z are 1 <x + y ≦ 10,000.
It is a positive integer satisfying the conditions of 0, 1 ≦ z ≦ 10,000, and x + y ≧ z. ) An oxidative polymer of fluorinated butadiene having a structural unit represented by 2. The following formula: Fluorination, characterized in that fluorinated butadiene represented by the formula (wherein X is as defined above) is copolymerized with oxygen in the presence or absence of a radical source (excluding oxygen). A method for producing an oxidation polymer of butadiene. 3. A radical polymerization initiator comprising the oxidative polymer according to claim 1. 4. A cross-linking agent for rubber, which comprises the oxidation polymer according to claim 1.