JPS6259610A - Production of fluorocarbon resin having crosslinked structure - Google Patents

Abstract

PURPOSE:To facilitate the production of the titled resin excellent in heat resistance, corrosion resistance, dimensional stability and loading resistance, by copolymerizing a fluorine-containing divinyl compound with a fluorine-containing vinyl compound in the presence of a specified polymerization initiator. CONSTITUTION:50mol% or above fluorine-containing divinyl compound (A) of formula I or the like formula is copolymerized with a fluorine-containing vinyl compound (B) of formula II (wherein X is F, Cl, Br, I, H, SO2F, SO2Cl, COOR, or CONR1R2, wherein R1-2 are each H or a 1-5 C alkyl) at -80-400 deg.C and a pressure of -70mmHg-20kg/cm<2> in an inert gas atmosphere such as N2 in the presence of 0.1-10wt%, based on the monomer, polymerization initiator (C) which can be readily dissolved in the mixed monomer solution, can be easily handled in air and shows a high polymerization activity at a temperature <= the b.p. of the monomer selected from among peroxydicarbonates and fluorine-containing diacyl peroxides.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for producing a fluorine-containing resin having a crosslinked structure by copolymerizing a fluorine-containing divinyl compound and a fluorine-containing vinyl compound, and in particular peroxydicarbonate or a fluorine-containing vinyl compound. and fluorine-containing diacyl peroxide in the presence of one or more polymerization fRI initiators selected from fluorine-containing diacyl peroxides, and copolymerizing the fluorine-containing vinyl compound under conditions where the fluorine-containing divinyl compound is contained in the total monomers in an amount of 50 mol% or more. The present invention provides a fluorine-containing resin that has particularly excellent heat resistance, chemical resistance, and dimensional stability.

[Prior Art and Problems] Conventionally, fluorine-containing resins have been used such as homopolymers of tetrafluoroethylene, tetrafluoroethylene and hexafluoropropylene, tetrafluoroethylene and ethylene, tetrafluoroethylene and perfluoroalkyl vinyl ether, and tetrafluoroethylene and hexafluoropropylene. Linear copolymers consisting of fluoroethylene, trifluoromonochloroethylene, etc. are known, and are obtained by polymerization using tetrafluoroethylene as a main component. Since such tetrafluoroethylene is a monomer having a boiling point of 176° C. at normal pressure, it is generally polymerized under high pressure. Also,
Since a fluorine-containing resin with excellent physical properties cannot be produced unless the molecular weight of the resulting polymer is increased, it is necessary to purify the fluorine-containing monomer and strictly control the polymerization. Moreover, the obtained fluorine-containing resin also has the disadvantage of poor U weight resistance.

Therefore, an object of the present invention is to provide a method for easily producing a crosslinked fluorine-containing resin in order to obtain a fluorine-containing resin with excellent rust resistance.

[Problems to be solved by the invention] In order to easily produce a fluorine-containing resin having a crosslinked structure, it is necessary that the monomers used be liquid at room temperature, and that the polymerization initiator be liquid or solid at room temperature. It is desirable that the polymer be stable even when in contact with air, be soluble in the monomer used, and have high polymerization activity at a temperature below the boiling point of the monomer.

[Means for Solving the Invention] In order to copolymerize a fluorine-containing divinyl monomer and a fluorine-containing vinyl monomer, the present inventor has developed a polymerization initiator that is liquid or solid at room temperature, easy to handle in air, and capable of achieving a high polymerization rate. As a result of intensive research on peroxydicarbonate and fluorine-containing diacyl peroxide, we found that peroxydicarbonate and fluorine-containing diacyl peroxide are extremely effective as polymerization catalysts, and when conducting polymerization, the fluorine-containing divinyl compound and the fluorine-containing vinyl compound can be used as a charging composition. It has been found that a high polymerization rate can be achieved by having 50 mol% or more of the total monomers present.The present invention is based on this knowledge.
A fluorine-containing divinyl monomer and a fluorine-containing vinyl monomer are combined in the presence of at least one polymerization initiator selected from peroxydicarbonate and fluorine-containing diacyl peroxide until the content of the fluorine-containing vinyl monomer in all monomers is 50%. This is a method for producing a fluorine-containing resin having a crosslinked structure, characterized in that copolymerization is carried out at a composition ratio of mol % or more.

Almost no double bonds or bonds are found in the fluorine-containing resin obtained according to the present invention, and the infrared absorption spectrum clearly shows that it is a completely crosslinked +'51 resin.

That is, the structure of the resin in the present invention is a three-dimensionally cross-linked resin, so it has a silky network structure in which each monomer unit is complexly contained, so the resin structure cannot be easily expressed, but the structure of the following formula can be used. A structure in which units are randomly intertwined by radical polymerization (in the formula, Rf is fluorine-containing alkylene, 1 ('f is fluorine-containing alkyl). In the present invention, CF2=CF, 0CF2CF20CF=CF2 is used as the fluorine-containing divinyl compound. As a result of confirming the structure of the smoothed resin using a molecular model, it is presumed that the following cyclic structure can be formed, although the degree of cyclization is unknown.

Hereinafter, the present invention will be explained in detail including the manufacturing method.

Examples of the fluorine-containing divinyl compound constituting the fluorine-containing polymer having a crosslinked structure of the present invention include CF 2 =CF
(CF 2)#, (OCFCF2), -,0CF=
CI-'2゜CF 2: CF (CF 2)/I, C
It is at least one type of compound represented by F=CF2 or the like.

In addition, as the fluorinated vinyl monomer, the formula 4% 02 ('J-, 5O2NR, R2, C0OR,, C0N
) (+ R2+ R+ y R2 is hydrogen or has 1 carbon number
~5 alkyl group), for example, CF2=CFOCF2CF2CF3
.

CF3 CF2-=CFOCFzCFoCF2CF2CF3゜C
F2=CFOCF2CF3. CF2=CF'0 (.

CF2)jcF3. CF2=CFO(CF2)4CF3
．． CF2=CFO(CF2)5 CF3. CF2:CF
OCF2CF2CFzCQ.

CF3 Hot CF2=CFOCF2CFOCF2F2(Qt(',
) i' 2 = CF OCF 2 CF 2 CF
2 H.

CF3. .

CF2=CFOCF2CFOCF 2CF2CF2II
, CF2 = CF OCF 2 CCQ, 3 +
F3 LingCF2=CFOCF2CFOCF2CF2G),.

CF 2 = CFOCF 2 C)? 21.

CF3 CF 2 = CF OCF' 2CF OCF 2
CF2I.

CII z ” Cl] COOC] 12 CF 3
.

Cf (2” CHCOOCH2CF 2CF 3.

This is a compound represented by F3.

In the present invention, in order to obtain a desired fluorine-containing resin having a crosslinked structure, it is extremely important to maintain the proportion of the fluorine-containing divinyl compound and the fluorine-mediated divinyl compound at 50 mol% or more. That is, if the charging ratio of all the monomers of the fluorine-containing divinyl compound is increased,
The polymerization rate becomes faster and a polymer with a three-dimensional crosslinked structure can be obtained at a high polymerization rate. On the other hand, if the charging ratio of the above-mentioned fluorine-containing divinyl compound is less than 50 mol %, the polymerization rate is low and it is impossible to obtain a fluororesin having the desired crosslinked structure.

In the present invention, selection of an initiator for copolymerizing the fluorine-containing divinyl compound and the fluorine-containing vinyl compound is also extremely important. That is, as an initiator for copolymerization, diacyl peroxide such as benzoyl peroxide, lauroyl peroxide, trichloroacetyl peroxide, acetyl peroxide, octanoyl peroxide, 2,4-dichlorobenzoyl peroxide,
Hydroperoxides such as cumene hydroperoxide and t-butyl hydroperoxide; dialkyl peroxides such as dicumyl peroxide and di-t-butyl peroxide; t-butyl peroxide neodecanoate; and t-butyl peroxide. Alkyl perester such as oxybiplate, bis(4-t-butylcyclohexyl)
peroxydicarbonate, diisopropyl peroxydicarbonate, di-2-ethylhexyl peroxydicarbonate, di-n-propylperoxydino-7-bonate, dimyristyl peroxydicarbonate, di-2-ethoxyethyl peroxydicarbonate, Dimethoxyisopropyl baroxydicarbonate, di(3
peroxydicarbonates such as -methyl-3-methoxybutyl) peroxydicarbonate, azo initiators such as azobisisobutyronitrile and azobiscyclohexanecarbonitrile, succinic acid peroxide,
General formula (where B is hydrogen or fluorine atom, m is 1-24,
n is 1-10), dipentafluoropropionyl peroxide, ditetrafluoroprobionyl peroxide, dihebutafluoroptyryl peroxide, di(trichlorooctafluorohexanoyl) peroxide, di(tetrachloroun) fluorine-containing disilver oxide such as decafluorooctanoyl peroxide, Shiba-fluoro-2-n-propoxyprobionyl peroxide, Shiba-fluoro-2-isopropoxyprobionyl peroxide, NF 3
+ N 2 F 4 + N 2 F 2 JCF
3 C(NF 2) ”C(NF 2) CF 3
.

Fluorine-containing elemental compounds such as CF3CF (NF2)C(NF)CF3, potassium persulfate, ammonia persulfate 11
or other initiators such as ultraviolet rays or ionizing radiation, which can be dissolved in the monomer mixture solution, can be handled in a container in air, and whose half-life temperature is Below the boiling point of the monomer used under normal pressure,
Moreover, an initiator capable of producing cross-[1] fat at a high polymerization rate is required. As the initiator of the present invention that satisfies these conditions, diacyl peroxides and peroxydicarbonates are preferred, and fluorine-containing diacyl peroxides and peroxydicarbonates are particularly preferred. By the way, N2F2+N
2Fd is a gaseous compound at room temperature that easily explodes on contact with organic compounds, and has low polymerization activity near room temperature, so it is necessary to raise the temperature stepwise and polymerize at a high temperature. Another problem is that when N2F4 comes into contact with air, it turns into nitrogen oxides and loses its catalytic activity. Furthermore,
For ultraviolet rays, it is difficult to obtain homogeneous bulk polymers. Therefore, it is presumed that these polymerization initiators are difficult to handle.

In addition to the above-mentioned fluorinated vinyl compounds, if necessary, C1i' 2 =CF 2 , CF 2
=CFCQ.

CF2CF=CF2. CF20CFH.

Fluorine-containing monomers such as CF z = C112, fine powders such as copolymers of polytetrafluoroethylene and hexafluoroethylene, copolymers of tetrafluoroethylene and hexafluoropropylene, lj combinations of tetrafluoroethylene and alkyl vinyl ethers, or oligomers and peroxides. It is also possible to polymerize by adding a solvent such as fluorohexane, perfluoroheptane, trichlorotrifluoroethane, perfluoropolyether.

The amount of the polymerization initiator added is 0.0% relative to the monomer. 1-10
% by weight, preferably from 0.5 to 5% by weight. Note that it is also possible to use these initiators after diluting them with an organic solvent. The polymerization temperature is from 100"C to 400°C, preferably from 10"C to !50°C. In order to complete the polymerization, the polymerization temperature may be raised stepwise. -70 mm 1 l in the presence of an inert gas such as
The form of polymerization, which is preferably carried out under a pressure of 20 kg to 20 kg/awe, may be any method such as bulk polymerization, solution polymerization, or suspension polymerization. Bulk polymerization is preferably carried out to reach a high polymerization rate.

In addition, during bulk polymerization, fluorine-containing resin, polyvinyl chloride resin, polypropylene resin, polyethylene resin, carbon a
Woven fabrics, knitted fabrics, non-woven fabrics, porous films, non-porous films, tubes, etc. made of fibers, iron, stainless steel, etc.
Polymerization is carried out in the presence of powders, wires, nets, bunched metal, sintered plates, etc. made of nickel, silver, zinc, titanium, copper, platinum, gold, etc., to improve the mechanical properties of fluorine-containing resins, and to improve the mechanical properties of fluorine-containing resins. Metal surfaces can also be coated by polymerizing monomers.

[Effects of the Invention] The crosslinked fluororesin of the present invention has excellent properties such as heat resistance, corrosion resistance, and dimensional stability, so it can be used in various fields.

In other words, the resin having a crosslinked structure of the present invention can be used in various industries because molded products can be obtained with easier operation than conventional resins whose main component is tetrafluoroethylene, and the mechanical properties do not change even at high temperatures. Effective as a material. For example, chemical plants, heating elements, bearings, piston rings,
It can be used as a material for aircraft, space development equipment, physics and chemistry instruments, etc.

Example 1 CF 2 =CFOCF 2 C in a glass ampoule
F20CF: CF2 (98% purity) and CF2=CF
A monomer consisting of OCF2CF2CF3 (purity 913%) was added to each specified amount shown in Table 1, and (
CF3. After charging CF2CF2C00)z to the total monomer weight %, nitrogen substitution was repeated under reduced pressure under dry ice and methanol, and a glass ampoule was melt-sealed under reduced pressure and polymerized between three fats at 20 °C. After that, the polymer was taken out and immersed in trichlorotrifluoroethane, passed through a glass filter, and dried under reduced pressure under heat to determine the polymerization rate of the polymer.

The results are shown in Table 1.

When a part of this polymer was cut into a thin film and its TR spectrum was measured, it was found that there was no absorption based on perfluorovinyl ether groups, and the polymerization rate was high, indicating that perfluorodivinyl ether and alkyl vinyl ether have a high polymerization rate. It is clear that crosslinking polymerization has occurred.

Comparative Example 1 Similar to Example 1, CF2=CFO(':F2CF20
When polymerization was carried out by reducing the proportion of CF=CF 2 in the total monomers, a viscous polymer could be obtained, but a good three-dimensional crosslinked product could not be obtained.

The results are also shown in Table 1.

Example 2 Similar to Example 1, CF2=CFOCF2CF20CF
= CFz (purity 98%) and CF3 ■ CF 2 = CFOCF 2 CFOCF2 CF 2
A monomer consisting of CF 3 (purity 98%) was added to each predetermined amount shown in Table 2, and as a waste initiator (CF 3 CF
After adding 2Coo)2 to the total monomer amount to 2% by weight, two parts were polymerized at 25° C., and the polymerization rate was determined by drying under reduced pressure. The results are shown in Table 1.

Comparative Example 2 Similar to Example 2, CF2=cFOCF2 CF2OC
When polymerization was carried out with a lower proportion of F = CF 20 in the total monomers, a good three-dimensionally crosslinked polymer was not obtained. These results are also shown in Table 2.

Example;) CF2:CFO(CF2)r 0CF=CF2 (97% purity) 9 heavy electric parts and CF2=CFOCF2CF2CF3
(purity ≦ 8%)) to a monomer mixture solution consisting of 1 part by weight,
0.3 parts by weight of diisobrobyl peroxydicarbonate) was added and polymerized in a glass ampoule at 30° C. for 2 days. The polymerization rate was measured by the method of Example 1 and was found to be 85%.

Example 4 CF2=CFO (CF, ri40CF=CF2 (purity 9
Fi%) 8 heavy electric section and CF2=CFOCF2CF2CF
3 (purity 98%) to a monomer mixture consisting of 5 parts of double,
A monomer mixture containing 0.2 parts of diisopropylburoxydicarbonate (diisopropyl baroxydicarbonate) was charged into a stainless steel autoclave, and the mixture was heated at 1 (5°C) under a nitrogen pressure of 4 kg/(2)2.
After polymerization for one day, a resin without air bubbles was obtained. When the polymerization rate was measured by the method of Example 1, it was 90%.

Example 5 CF2=CFO(CF2)3ocF'==cr2 (98% purity) 7 heavy electrical parts and CF3 CF" 2 = CF OCF 2 CF
A monomer mixture F3 consisting of 3 parts by weight of OCF 2 CF 2 CF 3 (purity 98%) was added with (CF3CF2CF20CFCOO) at 20°: The polymerization rate was measured at 91%.

Claims (3)

[Claims] (1) The fluorine-containing divinyl compound and the fluorine-containing vinyl compound are mixed in the presence of one or more polymerization initiators selected from peroxydicarbonate or fluorine-containing diacyl peroxide, so that the content of the fluorine-containing divinyl compound in all monomers is 50%. A method for producing a fluorine-containing resin, characterized by copolymerizing at a composition ratio of mol% or more. (2) The method for producing a fluorine-containing resin according to claim 1, wherein the fluorine-containing divinyl compound is a perfluorodivinyl ether compound. (3) The method for producing a fluorine-containing resin according to claim 1, wherein the fluorine-containing vinyl compound is a fluorine-containing vinyl ether compound.