JP2003268045A - Tetrafluoroethylene-ethylene based copolymer and film of the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tetrafluoroethylene-ethylene based copolymer excellent in flexibility, weather resistance, durability, transparency, strength, non- adhessiveness, etc., and to provide a film, and to provide a use thereof. <P>SOLUTION: The copolymer based on tetrafluoroethylene-ethylene which has a tetrafluoroethylene monomer/ethylene monomer molar ratio of 50/50 to 70/30, and contains 10-30 mole.% of a vinyl aliphatic carboxylate (aliphatic carboxy group is a linear 6-18C aliphatic group or a branched 9-18C aliphatic group.), and has a volume flow rate of 0.01 to 1000 mm<SP>3</SP>/sec. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a novel tetrafluoroethylene-ethylene copolymer (hereinafter referred to as ETFE copolymer) and flexibility, weather resistance, dust resistance, and the like using the ETFE copolymer. The present invention relates to a film having excellent transparency, high strength, non-adhesiveness, etc., and further to an agricultural coating material, a release film and an interlayer film for laminated glass, which are made of this film.

[0002]

2. Description of the Related Art Conventionally, films made of polyethylene, ethylene-vinyl acetate copolymer, polyester resin, soft vinyl chloride resin, etc. have been used as agricultural coating materials for tunnel houses and pipe houses. In particular, a film made of a soft vinyl chloride resin is excellent in workability, price, moisturizing property, etc. and is most often used as a covering material for agriculture. However, since the soft vinyl chloride resin contains a plasticizer, the plasticizer bleeds out from the film, the surface of the film is easily soiled, and the light transmittance is lowered in a short period of time.

Further, although an ultraviolet absorber is added to the above film to improve weather resistance,
Due to deterioration due to temperature, weather, oxidation, etc., it is usually necessary to replace the film within 1 to 2 years. Moreover, the film containing the above-mentioned ultraviolet absorber shields ultraviolet rays although the degree of ultraviolet absorption varies. Therefore, crops that require UV light (eg, eggplants and some flowers)
Crop that is pollinated by honeybees, maha flies, etc. that require ultraviolet rays for cultivation and activity of (for example, strawberries,
It is also not suitable for cultivation of melons, watermelons, peppers).

Further, in recent years, full-scale large-scale houses have been adopted for the purpose of labor saving of house management, expansion of cultivation area, extension of house life, and the like. Conventionally, plate-shaped agricultural coating materials such as polyester resin, polycarbonate resin, hard vinyl chloride resin, acrylic resin, fiber reinforced plastics, and inorganic plate glass have been used for this large-sized house, and long-term extension of 5 years or more has been achieved. It is possible. However, these agricultural covering materials are thick and heavy, and must be spread on a house with a large-scale dedicated base material frame, and the spreading work is complicated and relatively expensive. There are drawbacks. Agricultural coating materials such as polyester resins, polycarbonate resins, hard vinyl chloride resins, and acrylic resins have the drawback that cracks are likely to occur due to the hail and the cracks that have been propagated easily. further,
In many cases, these plate-shaped agricultural coating materials also contain an ultraviolet absorber, and like the above-mentioned film, there are problems caused by the ultraviolet absorber.

A film made of a fluororesin has been proposed as an agricultural coating material that solves the above problems. The fluororesin has excellent properties such as excellent weather resistance and acid rain resistance, excellent stain resistance, easy cleaning of surface stains with rain water, and less breakage. In particular, a film made of an ETFE copolymer has properties such as excellent heat resistance and weather resistance, high light transmittance, and excellent non-adhesiveness, and has been commercialized as an agricultural coating material for 10 years. The above long-term use is possible.

By the way, in the case of covering materials for agriculture, when the film is spread on a pipe house or the like, a construction method is adopted in which the fixing member is fixed to the frame of the house while the tension of the film is not loosened. . However, conventional E
A film made of a TFE copolymer has a large tensile elastic modulus and a low flexibility, so that it is necessary to pull and fix the film with a large force, which is a problem in construction.

A film made of an ETFE copolymer is used as a release film when molding a printed wiring board because of its excellent properties such as non-adhesiveness and heat resistance. In this application, the film made of the conventional ETFE copolymer has a high tensile elastic modulus, and there is a problem that the conformability to a printed wiring board having a complicated shape is not sufficient.

Further, since the ETFE copolymer has characteristics such as excellent transparency, it is also used as an interlayer film for laminated glass used for safety glass and the like. However, the film made of the conventional ETFE copolymer has a high tensile elastic modulus, has insufficient adhesion to glass and workability, and has insufficient shock absorption at the time of glass breakage.

In any of the above applications, ET having a low elastic modulus
The development of FE copolymer was requested.

As a solution to this problem, a method of blending a resin with a flexible elastomer has been proposed.
WO99 / 67333 describes a film having a low elastic modulus and excellent flexibility obtained by blending an ETFE copolymer and a tetrafluoroethylene-propylene elastic copolymer. However, with this method, although the film characteristics are excellent, there is a problem that the molding process becomes complicated.

As a method for improving the ETFE copolymer itself, WO 01/19880 discloses a third method in addition to tetrafluoroethylene (hereinafter referred to as TFE) and ethylene (hereinafter referred to as E). A method for obtaining an ETFE polymer having a low elastic modulus by copolymerizing a specific aliphatic vinyl carboxylate as a component has been proposed.
In the examples, the ratio of polymerized units based on TFE / polymerized units based on ethylene is 37.8 / 62.2 to 47.0 / 5.
3.0 (molar ratio) and 2.5 to 9.2 of the polymerized units based on the specific aliphatic vinyl carboxylate in the copolymer.
Films of ETFE copolymer containing mol% are described. However, it was found that the film made of the ETFE copolymer described in the examples has a low tensile elastic modulus, but does not have sufficient weather resistance and is not suitable for a long-term extension of 5 years or more.

[0012]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above problems and provide a novel ETFE copolymer having a low tensile modulus without lowering weather resistance.

Another object of the present invention is to provide a film made of the above-mentioned ETFE copolymer, and an agricultural coating material, a release film and an interlayer film for laminated glass, which are obtained by using this film.

[0014]

According to the present invention, the molar ratio of polymerized units based on TFE / polymerized units based on E is 50/50.
To 70/30, and aliphatic vinyl carboxylate (provided that the aliphatic carboxy group has 6 to 18 carbon atoms, and the branched aliphatic carboxyl group has 9 to 18 carbon atoms).
Is. ), And the volumetric flow rate is 0.01 to 1000 mm ^3.
/ Sec is provided.

The present invention also provides an ETFE copolymer film comprising the above ETFE copolymer, an agricultural coating material using the film, a release film and an interlayer film for laminated glass.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION In the ETFE copolymer of the present invention, the ratio of TFE-based polymerized units / E-based polymerized units is 50/50 to 70/30 (molar ratio). If this ratio is less than 50/50, the weather resistance is insufficient,
When it is larger than 70/30, the transparency is lowered. Within this range, the weather resistance is excellent, and the transparency, heat resistance, and non-adhesiveness are excellent. It is preferably 52/48 to 66/34, more preferably 54/46 to 64/36.

In the ETFE copolymer of the present invention, the third
Aliphatic carboxy group (hereinafter referred to as AC) in the component aliphatic vinyl carboxylate (hereinafter referred to as ACV _E )
Has 6 to 18 carbon atoms, and AC has a branched structure having 9 to 18 carbon atoms. If the carbon number of AC is smaller than 6 in the straight chain structure or the carbon number of AC is smaller than 9 in the branched structure, the low tensile elastic modulus is not obtained. On the other hand, when the carbon number of AC is larger than 18, it is difficult to control the copolymerization composition during the production of the ETFE copolymer, and the strength of the obtained polymer tends to decrease. Within this range, the flexibility is excellent, the strength is high, and the weather resistance is excellent.

Preferably, AC has 6 to 12 carbon atoms, and AC having a branched structure has 9 to 12 carbon atoms, and more preferably AC has 6 to 10 carbon atoms.
In the case of AC having a branched structure, its carbon number is 9 to 10.
Particularly, AC having a branched structure is preferable, and the obtained film has excellent weather resistance. A part of hydrogen atoms on the carbon atom of AC may be replaced with a halogen atom such as a chlorine atom and a fluorine atom. Moreover, ACV _E may be used individually by 1 type, and may use 2 or more types together.

ACV_EA specific example of
Nyl (AC has 6 carbon atoms. Hereinafter, C₆V_EToi
U ), Vinyl caprylate (hereinafter C₈V_EToi
U ), Vinyl caprate (hereinafter C₁₀V_EToi
U ), Veova 9, Versatic vinylate (1 carbon
Vinyl ester of a mixture of ACs with 0 branched structure. Less than,
BC₁₀V _EAlso called. Japan Epoxy as a commercial product
There is VEOVA 10 made by Resin Co. ), Vinyl laurate
(Hereafter, C₁₂V_ESay. ), Vinyl myristate
(Hereafter, C₁₄V_ESay. ), Vinyl palmitate
(Hereafter, C₁₆V_ESay. ), Vinyl stearate
(Hereafter, C₁₈V_ESay. ) And the like. Preferred
ACV_EBut C₆V_E, C₈V_E, C₁₀V_E,
BC₁₀V_EAnd C₁₂V_EA few selected from the group consisting of
At least one. More preferably C₆V_E, C₈V
_E, C₁₀V_EAnd BC₁₀V_EAnd most preferably
Is BC₁₀V_EIs.

The ETFE copolymer contains more than 10 mol% and not more than 30 mol% of polymerized units based on ACV _E. 1
If it is 0 mol% or less, the weather resistance of the film is insufficient, and 3
If it exceeds 0 mol%, the strength of the film tends to decrease. Within this range, the film is excellent in flexibility, weather resistance, transparency and mechanical strength. The polymerized units based on ACV _E are preferably 10.0 to 25.0 mol%, and 10.5 to 20
Mol% is more preferable, and 11.0 to 18.0 mol% is the most preferable.

The ETFE copolymer of the present invention includes TFE,
In addition to polymerized units based on E and ACV _E , it is also preferable to contain polymerized units based on other monomers than TFE, E and ACV _E.

Other monomers include propylene,
Butene and other olefins (excluding E), vinyl fluoride, vinylidene fluoride, and other fluoro groups having hydrogen atoms in unsaturated groups, hexafluoropropylene,
Fluoroolefins having no hydrogen atoms in unsaturated groups such as chlorotrifluoroethylene and perfluoro (alkyl vinyl ether) (excluding TFE), alkyl vinyl ether, (fluoroalkyl) vinyl ether, glycidyl vinyl ether, hydroxybutyl vinyl ether, methyl vinyloxy Vinyl ethers such as butyl carbonate, (polyfluoroalkyl) acrylates, (meth) acrylic acid esters such as (polyfluoroalkyl) methacrylate, unsaturated carboxylic acids such as undecylenic acid, acrylic acid, methacrylic acid, general formula CH _{2
= CX (CF 2) n Y} ( wherein X and Y are independently hydrogen or fluorine atom, n represents an integer of 2-8) include compounds represented by.

Preferably, the olefin and the unsaturated group are hydrogen.
Fluoroolefins having atoms, hydrogen atoms in unsaturated groups
Fluoro-olefin or CH having no_Two= CX (CF
_Two) _nIt is Y.

CH_Two= CX (CF_Two)_nAs a specific example of Y
For CH_Two= CF (CF_Two)_TwoF, CH_Two= CF (C
F_Two)_ThreeF, CH_Two= CF (CF_Two)_FourF, CH_Two= C
F (CF_Two)_TwoH, CH_Two= CF (CF_Two)_ThreeH, CH
_Two= CF (CF_Two)_FourH, CH_Two= CH (CF_Two)
_TwoF, CH_Two= CH (CF_Two)_ThreeF, CH_Two= CH (C
F _Two)_FourF, CH_Two= CH (CF_Two)_TwoH, CH_Two= C
H (CF_Two)_ThreeH, CH_Two= CH (CF_Two)_FourH etc.
You can Especially CH_Two= CF (CF_Two)_TwoF, CH_Two
= CH (CF_Two)_TwoF, CH_Two= CH (CF_Two)_TwoH,
CH_Two= CF (CF _Two)_TwoH is preferred.

The volume flow rate of the ETFE copolymer in the present invention is 0.01 to 1000 mm ³ / sec. If the volume flow rate is less than 0.01 mm ³ / sec, it will be difficult to mold the copolymer, and if it exceeds 1000 mm ³ / sec, the strength will be insufficient. Volume flow rate is preferably 1~600mm ³ / sec, 3~300mm ³ / sec is more preferable. The volume flow velocity in the present invention, using a Shimadzu flow tester,
Under a load of 0.7 MPa at 200 ° C., a diameter of 2.1 mm,
It is a value defined as the volume (mm ³ / sec) of the ETFE copolymer flowing out from a nozzle having a length of 8 mm in a unit time. Volumetric flow rate is a measure of molecular weight, with lower volumetric flow rate indicating higher average molecular weight of the ETFE copolymer.

The method for producing the ETFE copolymer of the present invention is not particularly limited, and a generally used polymerization method using a radical polymerization initiator is used. As the polymerization method,
Bulk polymerization, fluorinated hydrocarbons, fluorinated hydrocarbon ethers,
Solution polymerization using an organic medium such as fluorinated hydrocarbons, chlorinated hydrocarbons, alcohols and hydrocarbons, suspension polymerization using an aqueous medium and optionally the organic medium, emulsion polymerization using an aqueous medium and an emulsifier. Is exemplified. Particularly, solution polymerization or suspension polymerization is preferable.

The radical polymerization initiator has a half-life of 1
The decomposition temperature, which is 0 hour, is preferably 0 ° C to 100 ° C, and 2
0-90 degreeC is more preferable. Specific examples include azo compounds such as azobisisobutyronitrile, non-fluorinated diacyl peroxides such as isobutyryl peroxide, octanoyl peroxide, benzoyl peroxide and lauroyl peroxide, and peroxydicarbonates such as diisopropyl peroxydicarbonate. , T
Peroxyesters such as ert-butylperoxypivalate, tert-butylperoxyisobutyrate, tert-butylperoxyacetate, (X (C
F ₂ ) _p COO) ₂ (where X is a hydrogen atom, a fluorine atom or a chlorine atom, and p is an integer of 1 to 10.)
Examples thereof include fluorine-containing diacyl peroxides such as compounds represented by, and inorganic peroxides such as potassium persulfate, sodium persulfate and ammonium persulfate.

The polymerization conditions are not particularly limited, and the polymerization temperature is 0.
C.-100.degree. C. is preferable, and 20.degree.-90.degree. C. is more preferable. The polymerization pressure is preferably 0.1 to 10 MPa, and is 0.5
˜3 MPa is more preferred. The polymerization time is preferably 1 to 30 hours.

The ETFE copolymer of the present invention is formed into a film by a known method such as an inflation method or an extrusion molding method. The screw temperature of the extruder in the extrusion molding method is preferably 100 to 350 ° C.

The thickness of the film obtained by molding the ETFE copolymer of the present invention is preferably 5 to 300 μm,
200 μm is more preferable, and 20 to 150 μm is most preferable. If it is too thin, it will be easily broken, and if it is too thick, the light transmittance will decrease, and the workability such as cutting and adhesion, and the spreading workability will be insufficient. The width of the film is 1000-20
00 mm is preferable, and in this range, the film is excellent in moldability and handleability.

The tensile modulus of elasticity of the film comprising the ETFE copolymer of the present invention is preferably 10 to 500 MPa,
-400 MPa is more preferable. Within this range, it can be easily fixed to the frame of a small tunnel house or pipe house, which is preferable. The tensile modulus is measured by a method according to ASTM D-1708.

The film made of the ETFE copolymer of the present invention has a high total light transmittance. The higher the total light transmittance,
Shows excellent transparency. The total light transmittance is preferably 93% or more, more preferably 94% or more.

The film made of the ETFE copolymer of the present invention preferably contains, as a colorant, titanium oxide, zinc white, calcium carbonate, sinking silica, carbon black, chrome yellow, phthalocyanine blue, phthalocyanine green and the like. .

The film made of the ETFE copolymer of the present invention has a low tensile elastic modulus, is flexible, has excellent weather resistance, and is excellent in transparency, so that it can be used in tunnels including large greenhouses for facility cultivation of crops. It is used as a covering material for agriculture that can be spread on houses and pipe houses.

In general, the inside of a house is hot and humid, and condensed water droplets tend to adhere to the inside of the ceiling and walls. Therefore, it is preferable to treat at least the inside surface of the film with a drip agent. As the dropping agent, for example, an alcohol-soluble type or a water-dispersed type is preferable, and a composition in which a hydrophilic colloid substance is mixed with a fluoropolymer such as polyfluoroacrylate, or a composition in which a surfactant is mixed with a hydrophilic polymer And a composition in which a hydrophilic polymer is mixed with a surfactant and a hydrophilic colloidal substance.

As the hydrophilic colloidal substance, colloidal silica, colloidal alumina, colloidal titania and the like are preferable. As the hydrophilic polymer, and polyvinyl _{alcohol, -SO 3 H, -COOH, -NH} 2,
_{-CN, - (OCH 2 CH 2} ) m - (m is usually 1
Is an integer of -20. Polymers having hydrophilic functional groups such as) are used. The surfactant may be any of anionic, cationic or nonionic surfactants.

The film made of the ETFE copolymer of the present invention has excellent flexibility, heat resistance and non-adhesiveness, and is therefore used as an excellent release film at the time of molding a printed wiring board. Further, since it is excellent in flexibility, strength and transparency, it is used as an excellent interlayer film for laminated glass such as safety glass.

The film made of the ETFE copolymer of the present invention has a low tensile elastic modulus, excellent flexibility, weather resistance and
It is excellent as dust-proof property, strength, non-adhesiveness and transparency, and is therefore preferable as an agricultural coating material.

The ETFE copolymer and the film made of the ETFE copolymer of the present invention can be used in addition to agricultural coating materials, release films or interlayer films for laminated glass, electric wire coating materials,
It can also be used for applications such as tubes, hoses, and injection molded products.

The reason why the film made of the ETFE copolymer of the present invention has various excellent properties is not always clear. However, the reason why the tensile modulus is low and the flexibility is excellent is that A which is a constituent component of the ETFE copolymer is used.
By containing the polymerized units based on CV _E, ETF
The change in crystallinity of the ETFE copolymer due to having an AC group having a specific carbon number as a side chain of the E copolymer and the A
It is considered to be due to the synergistic effect of internal plasticization by the C group. The reason why the polymer has excellent weather resistance is that the property of polymerized units based on TFE, which is excellent in weather resistance, can be imparted by setting the molar ratio of polymerized units based on TFE / polymerized units based on E to 50/50 or more. It is considered to be something.

[0041]

The present invention will be described in detail with reference to the following examples, but the present invention is not limited thereto. Examples 1 to 3 and 6 are examples, and Examples 4 and 5 are comparative examples.
The composition, tensile modulus, tensile strength, total light transmittance, weather resistance and spreading workability of the ETFE copolymer were measured by the following methods.

[Composition of ETFE Copolymer] It was determined by melting NMR analysis and fluorine content analysis.

[Tensile Elastic Modulus] The tensile elastic modulus was measured according to ASTM D-1708. Microdumbbell shaped sample at temperature 2
A stress-strain curve is obtained by holding for 40 hours in an atmosphere of 5 ° C. and 50% relative humidity, and then performing a tensile test at a crosshead speed of 1.3 mm / min and a grip distance of 22 mm. The tensile elastic modulus is defined as a value obtained by dividing the slope of a portion where the stress changes linearly with respect to the strain change of the stress-strain curve up to the yield point, that is, the stress change amount (MPa) by the strain. Here, the strain is the amount of change in elongation (m
It is a dimensionless number obtained by dividing m) by the initial value (mm).

[Tensile Strength] The tensile strength was measured according to ASTM D-1708.

[Total Light Transmittance] In accordance with JIS K7105, a haze meter (manufactured by Nippon Seimitsu Optical Co., SEP-
The total light transmittance (%) was measured using T). The higher the total light transmittance, the better the transparency.

[Weather resistance] Using a super accelerated weather resistance tester (Iwasaki Electric Co., Ltd., Eye Super UV Tester, SUV-W23), UV light of 295 nm or more was used, and temperature was 63 ° C. and humidity was 50% for 10 hours. Irradiation, 2 hours Condensation 12 hours
When the film was irradiated with UV light for 300 hours under the conditions of cycling, the presence or absence of whitening of the film was evaluated. ○ indicates that there is no whitening, and × indicates that there is whitening. The whitened film was judged to have low weather resistance.

[Expansion workability] The degree of difficulty of the operation of expanding the film on a pipe house and fixing it to the frame using a fixing member was evaluated in comparison with a soft vinyl chloride resin. ○ indicates that the construction is easy, △ indicates that the construction is slightly difficult, and × indicates that the construction is possible, but it is hard and labor-intensive, and wrinkles easily form in the film.

Example 1 Internal volume with deaerated stirrer 1.
In a 2 liter stainless steel autoclave, 870.7 g of perfluoropentyldifluoromethane (hereinafter referred to as C6H), 222.1 g of deionized water, T
121.6 g of FE, 5.4 g of E, 1 of Veova 10
1.8 g was charged and the temperature was raised to 66 ° C. Then ter
18 ml of a 3% by mass C6H solution of t-butylperoxypivalate was injected under pressure to start the polymerization reaction.

In order to make up for the pressure which decreases with the progress of polymerization, a monomer mixed gas having a TFE / E composition of 60/40 (molar ratio) was introduced and the polymerization was continued while maintaining the pressure of 1.50 MPa. . As the monomer mixed gas is consumed, the amount of Veova 10 is 0.
26 g was added and polymerization was continued for 4.4 hours.

Then the autoclave is cooled to room temperature,
The pressure was purged to atmospheric pressure. Using the obtained dispersion liquid of the ETFE copolymer, after granulation, washing and vacuum drying, white E
82.3 g of TFE copolymer 1 was obtained. The composition of ETFE copolymer 1 was such that the ratio of polymerized units based on TFE / polymerized units based on ethylene was 59.5 / 40.5 (molar ratio), and the content of polymerized units based on Veova 10 was 12.5. Mol% and the volume flow rate at 200 ° C. is 24.3 mm ³ /
It was seconds.

ETFE copolymer 1 was press-molded at 200 ° C. to obtain a film having a thickness of 100 μm. The tensile modulus (MPa), tensile strength (MPa), total light transmittance, weather resistance and spreading workability of this film were measured. The results are shown in Table 1.
Shown in.

Example 2 Internal volume with degassed stirrer 1.
C6H in a 2 liter stainless steel autoclave
870.7 g, 222.1 g deionized water, 121.6 g TFE, 5.4 g E, 7.94 g Veova 10
Was charged and the temperature was raised to 66 ° C. Then, 15.3% by mass solution of tert-butyl peroxypivalate in C6H.
8 ml was injected under pressure to start the polymerization reaction.

In order to compensate for the pressure which decreases with the progress of polymerization, a monomer mixed gas having a TFE / E composition of 60/40 (molar ratio) was introduced and the polymerization was continued while maintaining the pressure of 1.57 MPa. . As the monomer mixed gas is consumed, the amount of Veova 10 is 0.
It was added at a rate of 31 g and the polymerization was continued for 3.4 hours.

83.4 of white ETFE copolymer 2 was obtained from the obtained dispersion liquid of ETFE copolymer in the same manner as in Example 1.
g was obtained. The composition of ETFE copolymer 2 is such that the ratio of polymerized units based on TFE / polymerized units based on E is 59.8 / 4.
At 0.2 (molar ratio), the content of polymerized units based on Veova 10 was 12.7 mol%, and the volume flow rate at 200 ° C. was 18.2 mm ³ / sec.

ETFE copolymer 2 was press-molded at 200 ° C. to obtain a film having a thickness of 100 μm. The characteristics of this film were measured as in Example 1. The results are shown in Table 1.

Example 3 Internal volume with degassed stirrer 1.
C6H in a 2 liter stainless steel autoclave
1244 g, TFE 163.9 g, ethylene 6.
1 g and 29.9 g of Veova 10 were charged and the temperature was raised to 66 ° C. Then, 2% by mass of tert-butylperoxypivalate 1,3-dichloro-1,1,2,2,3-pentafluoropropane (manufactured by Asahi Glass Co., Ltd., hereinafter 225cb
Say. ) A solution (30.0 ml) was injected under pressure to start the polymerization reaction.

In order to compensate for the pressure that decreases with the progress of polymerization, a monomer mixed gas having a TFE / E composition of 60/40 (molar ratio) was introduced and the polymerization was continued while maintaining the pressure of 1.46 MPa. . As the monomer mixed gas is consumed, the amount of Veova 10 is 0.
It was added at a rate of 39 g and the reaction was continued for 8.1 hours.

In the same manner as in Example 1, 114.3 g of ETFE copolymer 3 was obtained from the obtained dispersion liquid of ETFE copolymer. The composition of ETFE copolymer 3 was such that the ratio of polymerized units based on TFE / polymerized units based on E was 61.1 / 38.
9 (molar ratio), the content of polymerized units based on Veova 10 was 17.4 mol%, and the volume flow rate at 200 ° C. was 28.
It was 8 mm ³ / sec.

ETFE copolymer 3 was press-molded at 200 ° C. to produce a film having a thickness of 80 μm. The characteristics of this film were measured as in Example 1. The results are shown in Table 1.

Example 4 (Comparative Example) In a degassed stirrer-equipped stainless steel autoclave with an internal volume of 1 liter,
Charge 1,896 g of 1,1,2-trichloro-1,1,2-trichloroethane (hereinafter referred to as R-113), 61 g of TFE, 19 g of _E , 14.1 g of C ₈ V _E ,
The temperature was raised to 67 ° C. Then, 6 ml of a 3 mass% perfluorocyclohexane solution of tert-butylperoxyisobutyrate was pressure-injected to start the polymerization reaction.

In order to compensate for the pressure that decreases as the polymerization progresses, a monomer mixed gas having a TFE / E composition of 42/58 (molar ratio) was introduced, and the polymerization was continued while maintaining the pressure of 1.49 MPa. . As the monomer mixed gas is consumed, C ₈ V _E is 0.2 with respect to 1 g of the monomer mixed gas.
It was added at a rate of g and the reaction was continued for 2.5 hours.

Examples from dispersions of the ETFE copolymer obtained
99.9% of white ETFE copolymer 4 in the same manner as 1.
g was obtained. The composition of ETFE copolymer 4 is based on TFE.
Polymerized units / polymerized units based on ethylene are 42.2 / 5
7.8 (molar ratio), C₈V _EInclusion of polymerized units based on
The amount is 5.5 (mol%) and the volume flow rate at 230 ° C is
30.5 mm^Three/ Sec.

ETFE copolymer 4 was press-molded at 230 ° C. to obtain a film having a thickness of 60 μm. The characteristics of this film were measured as in Example 1. The results are shown in Table 1.

Example 5 (Comparative Example) In a degassed stirrer-equipped stainless steel autoclave with an internal volume of 1 liter,
R-113 866g, TFE 70g, E 22g,
30.6 g of C ₁₈ V _E was charged and the temperature was raised to 67 ° C.
Then tert-butyl peroxyisobutyrate 3
8 ml of a mass% perfluorocyclohexane solution was injected under pressure to start the polymerization reaction.

Pressure is 1.72 MPa to 1.65 MPa
Polymerization was carried out until the temperature reached, then the autoclave was cooled to room temperature, and the pressure was purged to atmospheric pressure. ETFE obtained
The copolymer dispersion is filtered, washed and dried, then white ETF
9.1 g of E copolymer 5 was obtained. The composition of the ETFE copolymer 5 was as follows: TFE-based polymer units / ethylene-based polymer units 37.8 / 62.2 (molar ratio), and C ₁₈ V _E
The content of polymerized units based on is 5.5 (mol%),
The volumetric flow rate at 230 ° C. was 653 mm ³ / sec.

ETFE copolymer 5 was press-molded at 230 ° C. to obtain a film having a thickness of 60 μm. The characteristics of this film were measured as in Example 1. The results are shown in Table 1.

[0067]

[Table 1]

[Example 6] Internal volume with degassed stirrer 1.
C6H in a 2 liter stainless steel autoclave
1244 g, TFE 137.7 g, ethylene 9.
3 g and 24.6 g of Veova 10 were charged and the temperature was raised to 66 ° C. Then, 20.0 ml of a 2% by mass 225 cb solution of tert-butyl peroxypivalate was injected under pressure to start the polymerization reaction.

In order to compensate for the pressure that decreases with the progress of polymerization, a monomer mixed gas having a TFE / E composition of 55/45 (molar ratio) was introduced, and the polymerization was continued while maintaining the pressure of 1.46 MPa. . As the monomer mixed gas is consumed, the amount of Veova 10 is 0.
The reaction was continued for 7.7 hours while adding at a rate of 28 g.

From the obtained dispersion liquid of ETFE copolymer, in the same manner as in Example 1, 124.
4 g was obtained. The composition of ETFE copolymer 6 is such that the ratio of polymerized units based on TFE / polymerized units based on E is 55.9 /
At 44.1 (molar ratio), the content of polymerized units based on Veova 10 was 14.9 mol%, and the volume flow rate at 200 ° C. was 10.4 mm ³ / sec.

ETFE copolymer 6 was press-molded at 190 ° C. to obtain a film having a thickness of 130 μm. This film has a tensile modulus of 312 MPa and a tensile strength of 36.6 MP.
a, the total light transmittance was 95%, the weather resistance was good, and the spreading workability was good, showing excellent properties.

As described above, the films of Examples 1 to 3 and 6 (Examples) are remarkably excellent in weather resistance, and also have a low tensile elastic modulus and excellent workability in spreading. It also has excellent transparency. On the other hand, the films of Example 4 (Comparative Example) and Example 5 (Comparative Example) both had low tensile modulus and excellent workability for spreading, but had low weather resistance. In addition, the films of Examples 1 to 3 and 6 have low tensile elastic modulus and excellent transparency, and thus are suitable as an interlayer film for laminated glass. Also, examples 1 to
The films of Examples 3 and 6 have low tensile elastic modulus and excellent non-tackiness, and thus are excellent as release films.

[0073]

The film made of the ETFE copolymer of the present invention has excellent weather resistance, low tensile modulus and excellent flexibility. It is also excellent in transparency, strength and non-adhesiveness. The film is useful as a covering material for agriculture, a release film, an interlayer film for laminated glass, and the like.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C08F 210: 02 C08F 218: 10 218: 10) C08L 27:18 C08L 27:18 F term (reference) 2B024 DB01 2B029 EB02 EC02 EC19 EC20 4F071 AA15X AA27X AA28X AH01 AH07 BA01 BB06 BB09 BC01 4J100 AA02Q AC26P AG02R AG05Q CA05 DA42 JA03 JA64

Claims (6)

[Claims] 1. A molar ratio of polymerized units based on tetrafluoroethylene / polymerized units based on ethylene is 50/50 to 7.
It is 0/30 and is based on an aliphatic vinyl carboxylate (however, the aliphatic carboxy group has 6 to 18 carbon atoms, and the aliphatic carboxy group having a branched structure has 9 to 18 carbon atoms). It contains more than 10 mol% and 30 mol% or less of polymerized units and has a volume flow rate of 0.01 to 1000 mm ³ /
A tetrafluoroethylene-ethylene-based copolymer, characterized in that it is a second. 2. The aliphatic vinyl carboxylate is at least one selected from the group consisting of vinyl caproate, vinyl caprylate, vinyl caprate, vinyl versatate and vinyl laurate. Tetrafluoroethylene-ethylene copolymer. 3. A film of a tetrafluoroethylene-ethylene-based copolymer comprising the tetrafluoroethylene-ethylene-based copolymer according to claim 1 or 2. 4. A covering material for agriculture comprising the film of the tetrafluoroethylene-ethylene copolymer according to claim 3. 5. A release film comprising the film of the tetrafluoroethylene-ethylene copolymer according to claim 3. 6. An interlayer film for laminated glass, which comprises the film of the tetrafluoroethylene-ethylene copolymer according to claim 3.