JPH0119408B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to ethylene-tetrafluoroethylene or chlorotrifluoroethylene-based copolymers, and more particularly to novel ethylene-tetrafluoroethylene or chlorotrifluoroethylene copolymers comprising ethylene, tetrafluoroethylene or chlorotrifluoroethylene, and specific fluorovinyl ethers. This invention relates to a chlorotrifluoroethylene copolymer. Ethylene-tetrafluoroethylene or chlorotrifluoroethylene copolymer (hereinafter referred to as E(C)
It's called TFE. ) has excellent chemical resistance, heat resistance, electrical properties, etc., and is also easy to heat-melt and process, so it is used in a wide range of fields as a material for various molded products, wire coverings, linings, coatings, etc. ing. In order to improve the properties of E(C)TFE, especially its high-temperature mechanical properties, it has been proposed to add various monomers as modifiers and copolymerize them. For example, U.S. Patent No. 3,624,250,
Publication No. 23671 and the like describes that E(C)TFE is copolymerized with a copolymerizable vinyl monomer that has no telogen activity and provides a side chain containing at least two carbon atoms. However, the E(C)TFE improved in this way is still not satisfactory in terms of high temperature strength and elongation, stress crack resistance, etc. Therefore, in view of this situation, the present inventors conducted research and found that E(C) using a specific fluorovinyl ether as a modifier.
When adding during copolymerization during TFE production,
It has been discovered that the high temperature strength and elongation and stress crack resistance of E(C)TFEE can be improved without impairing its properties, and the resulting copolymer has excellent heat resistance. They have also discovered that copolymerization reactivity is excellent when copolymerized with tetrafluoroethylene or chlorotrifluoroethylene, leading to the completion of the present invention. That is, the gist of the invention is to provide a repeating unit derived from ethylene, a repeating unit derived from tetrafluoroethylene or chlorotrifluoroethylene, and a repeating unit derived from the formula: [Wherein, X is hydrogen, fluorine or chlorine, and n is 1 to
Represents an integer of 10. ], the molar ratio of the repeating unit derived from ethylene to the repeating unit derived from tetrafluoroethylene or chlorotrifluoroethylene is 40:60 to 60:40. Yes, the content of repeating units derived from vinyl ether is
0.1-10 mol%, and the flow value at 300℃ is
The present invention is an ethylene-tetrafluoroethylene or chlorotrifluoroethylene copolymer characterized by a rate of 0.001 to 0.1 cc/min. Fluorovinyl ether () used in the present invention
is a known compound and can be easily synthesized, for example, by an ester/ether exchange reaction between vinyl acetate and a suitable fluoroalcohol. Specific examples of fluoroalcohols include HCF ₂ CH ₂ OH, H
(CF ₂ ) ₂ CH ₂ OH, H (CF ₂ ) ₄ CH ₂ OH, H
(CF ₂ ) ₈ CH ₂ OH, CF ₃ CH ₂ OH, CF ₃ CF ₂ CH ₂ OH,
F(CF ₂ ) ₈ CH ₂ OH, ClCF ₂ CH ₂ OH, Cl
Preferred examples include (CF ₂ ) ₂ CH ₂ OH and Cl(CF ₂ ) ₈ CH ₂ OH. In fluorovinyl ether (), if n is too large, it tends to impair the original physical properties of E(C)TFE and the copolymer reaction rate decreases, so it is not preferable that n is 11 or more. Fluorovinyl ether () is copolymerized in a proportion of 0.1 to 10 mol% based on the total copolymer. If the amount of fluorovinyl ether () is less than this lower limit, the high-temperature strength and elongation and stress crack resistance of the resulting copolymer will not be sufficiently improved; on the other hand, if it is more than this upper limit, E(C)TFE itself will not improve. The excellent physical properties of copolymerization are impaired, and the copolymerization rate decreases, making it uneconomical. The copolymer of the present invention can be produced by copolymerizing the above three types of monomers in the presence of a polymerization initiation source. Polymerization methods include bulk polymerization,
Any method such as solution polymerization, suspension polymerization, emulsion polymerization, or gas phase polymerization can be employed, and aqueous suspension polymerization is particularly preferred. As a polymerization initiation source, peroxide, azo compound,
It may be appropriately selected from ultraviolet rays, ionizing radiation, etc. depending on the polymerization method. Preferred polymerization initiation sources are peroxides, especially peroxides (e.g. di(chlorofluoroacyl) peroxide, di(perfluoroacyl) peroxide, di(ω-hydroperfluoroacyl) peroxide, etc.),
peroxyesters (such as t-butyl peroxyisobutyrate) and peroxycarbonates (such as diisopropyl peroxydicarbonate). When a solvent or a dispersion medium is used during copolymerization, for example, in the case of solution polymerization or suspension polymerization, halogenated hydrocarbons such as trichlorofluoromethane, dichlorodifluoromethane, dichlorofluoromethane, chlorodifluoromethane, trifluoromethane, Trichlorotrifluoroethane, dichlorotetrafluoroethane, chloropentafluoroethane, difluoroethane, water, and the like are preferably used, and these can be used alone or in combination. A chain transfer agent may be used to adjust the molecular weight of the copolymer, and preferred chain transfer agents include alkyl halides, paraffins, alcohols,
Examples include esters, ethers, and mercaptans. The polymerization temperature is usually 0 to 100°C, preferably 10 to 100°C.
The temperature is 70℃. Polymerization is usually carried out under pressure, preferably from 1 to
It is carried out under pressure of approximately 40 kg/cm ² G. In addition to the above-mentioned three types of monomers, other monomers may be added to the copolymer of the present invention as long as they do not adversely affect the resulting copolymer. Examples include propylene, hexafluoropropylene, trifluoropropylene, and butenes (1-butene, isobutene, fluorinated butene, halogenated butene, etc.). The flow value of the copolymer of the present invention produced in this way was determined using a Koka type flow tester at a load of 7.
Kg, 300 using a nozzle with a diameter of 2 mm and a length of 8 mm.
Measured in °C, it is usually 0.001 to 0.1 cc/min. The copolymer of the present invention not only has the excellent properties of E(C)TFE, but also has significantly improved properties in high temperature strength and elongation and stress crack resistance, less deterioration during molding, and heat resistance. The quality has also been improved. The copolymer of the present invention is preferably used for various molded products (eg, pipes, tubes, sheets, films, blocks, etc.), coatings (eg, powder coatings), linings, electric wire coatings, and the like. Next, examples will be shown to specifically explain the present invention. In the examples, the flow value, high temperature strength and elongation, and stress crack resistance were measured as follows: Flow value As described above. High temperature strength and elongation JIS dumbbells at 180℃ according to ASTM D638
The strength and elongation were measured at a tensile speed of 200 mm/min in a temperature atmosphere of . Stress crack resistance A test sample with a length of 38 mm x width of 13 mm x thickness of 2 mm was made with a notch, placed in a bending holder (according to ASTM D1693), and placed in air for 2 hours.
The temperature was increased at a rate of °C/min, and the temperature at which cracks were observed was measured. Example 1 12 pieces of deoxygenated and demineralized water were placed in a glass-lined polymerization tank with an internal volume of 30 mm, the air inside was replaced with nitrogen, the mixture was evacuated, and 10 kg of dichlorotetrafluoroethane was poured into the tank with sufficient stirring. internal temperature
It was kept at 15℃. In this, fluoroalkyl vinyl ether

[Formula] 56g was introduced, and then a mixture of ethylene/tetrafluoroethylene (molar ratio 18:82) was injected to a pressure of 6.8Kg/cm ² G. After adding 280ml of n-pentane as a molecular weight regulator,
22.4 g of di(ω-hydroperfluoroheptanoyl) peroxide was added as a polymerization initiator. Since the pressure decreased as the polymerization progressed, ethylene/tetrafluoroethylene/fluoroalkyl vinyl ether (mole ratio 48:50:2) was further pressurized to maintain the pressure at 6.8 Kg/cm ² G. 4.4 g of polymerization initiator was added every 5 hours. After 28 hours, the monomer and dichlorotetrafluoroethane were removed from the tank to obtain 4600 g of a white powdery copolymer. Copolymer composition: ethylene/tetrafluoroethylene/fluoroalkyl vinyl ether = 48:50:2. melting point
266℃. Flow value 1.28×10 ^-2 cc/min. A stress crack resistance test was conducted on a sheet molded from this copolymer, and as a result, no cracks occurred up to the melting point. Example 2 In Example 1, the initial amount of fluorovinyl ether was 76.5 g, and the amount of n-pentane added was 170 g.
ml, the molar ratio of the monomer mixture to be additionally injected is 47:
The same procedure was repeated except that the ratio was 50:3 and the polymerization was carried out for 34 hours to obtain 4740 g of a white powdery copolymer. Copolymer composition: ethylene/tetrafluoroethylene/fluoroalkyl vinyl ether = 47:50:
3. Melting point 261℃, flow value 0.56×10 ^-2 cc/min. A stress crack resistance test was conducted on a sheet molded from this copolymer, and as a result, no cracks occurred up to the melting point. Comparative Example 1 In Example 1, the polymerization pressure was set to 4 Kg/cm ² G, n
- The same procedure was repeated except that the amount of pentane charged was 200 ml and the fluoroalkyl vinyl ether was not charged to obtain 1260 g of a white powdery ethylene/tetrafluoroethylene copolymer. Melting point 284℃, flow value 0.61×10 ^-2 cc/min. A stress crack resistance test was conducted on a sheet molded from this copolymer, and as a result, cracks were observed to occur at 135°C. Example 3 In Example 1, fluorovinyl ether was

[Formula] was used, and 940 g of a white powdery copolymer was obtained by repeating the same procedure except that the initial charge amount was 25.8 g, the polymerization pressure was 6 Kg/cm ² G, and the polymerization time was 6 o'clock. . Copolymerization composition: ethylene/tetrafluoroethylene/fluoroalkyl vinyl ether = 48:50:2. Melting point 266℃.
Flow value 0.77×10 ^-2 cc/min. Example 4 In Example 1, fluorovinyl ether was

The same procedure was repeated except that the initial charge amount was 28.7 g, the pressure was 6 kg/cm ² G, and the reaction time was 5 hours, to obtain 830 g of a white powdery copolymer. Copolymer composition: ethylene/tetrafluoroethylene/fluoroalkyl vinyl ether = 48:50:2. Melting point 265℃. Flow value 0.60×10 ^-2 cc/min. The high temperature strength and elongation of the copolymers obtained in Example 1, Example 2 and Comparative Example 1 are shown in the table below.

【table】

Claims (1)

[Claims] 1. A repeating unit derived from ethylene, a repeating unit derived from tetrafluoroethylene or chlorotrifluoroethylene, and the formula: [Wherein, X is hydrogen, fluorine or chlorine, and n is 1 to
Represents an integer of 10. ], the molar ratio of the repeating unit derived from ethylene to the repeating unit derived from tetrafluoroethylene or chlorotrifluoroethylene is 40:60 to 60:40. Yes, the content of repeating units derived from vinyl ether is
0.1-10 mol%, and the flow value at 300℃ is
An ethylene-tetrafluoroethylene or chlorotrifluoroethylene copolymer characterized in that the rate is 0.001 to 0.1 cc/min. 2. The copolymer according to claim 1, wherein X in the formula representing vinyl ether is hydrogen. 3. The copolymer according to claim 1, wherein X in the formula representing vinyl ether is fluorine.