KR101385921B1 - Novel vinylidene fluoride copolymers and processes for production thereof - Google Patents

Abstract

Vinylidene fluoride air having a weight average molecular weight of 200,000 or more, having 99.9 to 90 mol% of vinylidene fluoride monomer units, 0.1 to 10 mol% of methylidene malonic ester monomer units, and 0 to 10 mol% of monomer units other than the monomer units. It relates to a modified vinylidene fluoride copolymer in which 10 to 90% of the total number of the ester groups included in the copolymer and the methylidene malonic acid ester monomer unit is hydrolyzed, and a method for producing them.

Description

Novel vinylidene fluoride copolymer and its manufacturing method {NOVEL VINYLIDENE FLUORIDE COPOLYMERS AND PROCESSES FOR PRODUCTION THEREOF}

The present invention relates to a vinylidene fluoride copolymer having excellent heat resistance, weather resistance, chemical resistance, and stain resistance, good adhesion, and reduced coloration during molding and a method for producing the vinylidene fluoride copolymer. The vinylidene fluoride copolymer obtained in the present invention is useful in the fields of various molded articles, binders, paints and the like.

Polyvinylidene fluoride resins composed of vinylidene fluoride units are used as materials for producing various films and molded articles by melt molding while being excellent in chemical resistance, weather resistance, and fouling resistance. Moreover, although it is used also as a coating material and a binder, since the adhesive strength with the base materials, such as a metal, is small for polyvinylidene fluoride resin, improvement of adhesive strength is calculated | required.

Conventionally, in order to improve the adhesive strength of polyvinylidene fluoride resin, copolymerization of vinylidene fluoride (hereinafter may be referred to as "VDF") with another monomer has been performed.

Generally, about the radical copolymerization of a vinyl monomer, the Qe theory which predicts the copolymerization reactivity in the radical polymerization of the monomer using the Q value which expresses the resonance effect of a vinyl monomer, and the e value which expresses a polar effect is advocated. It is becoming. By referring to this Qe theory, the copolymerizability of two different monomers can be predicted to some extent. (Polymer Society Edition, New Polymer Dictionary, First Edition, Asakura Shoten, November 25, 1988, p. See Patent Document 1), etc.)

However, the copolymerization of vinylidene fluoride with other vinyl monomers is based on the Qe theory due to the specificity of the hydrogenide ability of the vinylidene fluoride polymer radical being strong and the extremely high e value of vinylidene fluoride. The prediction was difficult. In addition, it is hard to say that the systematic investigation and research about the copolymerizability of vinylidene fluoride have been made enough, and the report example of the copolymer of vinylidene fluoride was limited. As the copolymer of vinylidene fluoride, copolymers with fluorine-containing monomers such as hexafluoropropylene and chlorotrifluoroethylene are known and commercialized (Satogawa Takaomi edition, "Fluorine Resin Handbook", First Edition, Nikkan Kogyo Shobunsha, November 30, 1990, p. 363 (Non-Patent Document 2), etc.), but these are not necessarily aimed at improving adhesiveness, and therefore, further improvement in adhesiveness is desired. It was.

Therefore, Japanese Unexamined Patent Publication No. 56-133309 (Patent Document 1) discloses that a polyvinylidene fluoride surface of a metal without a medium such as an adhesive by graft polymerization of an acrylic monomer on a skeleton of polyvinylidene fluoride irradiated with ionizing radiation. Shown is a method of treating it so that it can be directly adhered to. However, this method requires the large-scale facility in order to perform ionizing irradiation of radiation.

Japanese Patent Application Laid-Open No. 2-604 (Patent Document 2) discloses a copolymer of 40 to 95 mol% of vinylidene fluoride and 5 to 60 mol% of maleic anhydride using 90 parts of an acid anhydride using alcohol or water. It turns out that making the solvent solubility and crosslinking property of a copolymer favorable by ring opening to 100%.

In addition, JP-A-6-172452 (Patent Document 3) discloses 100 parts by weight of a monomer containing 80% by weight or more of vinylidene fluoride, and unsaturated dibasic acids such as maleic acid monomethyl ester and maleic acid monoethyl ester. The vinylidene fluoride copolymer which improved the adhesive force with metals etc. which were obtained by copolymerizing 0.1-3 weight part of monoesters of the ester is shown.

However, vinylidene fluoride copolymers having these esters or modified substances thereof have difficulty in heat resistance, and in melt molding, there is a problem in that the molded product is colored and the commodity value is lowered. .

Patent Document 1: Japanese Patent Application Laid-open No. 56-133309 (British Patent Application Publication No. 2082203) Patent Document 2: Japanese Patent Application Laid-Open No. 2-604 Patent Document 3: Japanese Unexamined Patent Publication No. Hei 6-172452 (U.S. Patent No. 5415958)

[Non-Patent Document 1] Polymer Society Edition, New Polymer Dictionary, First Edition, Asakura Shoten, November 25, 1988, p.99 [Non-Patent Document 2] Takao Satogawa, `` Fluorine Resin Handbook '', First Edition, Nikkan High School Shrine, November 30, 1990, p.363

The main object of the present invention is to provide a vinylidene fluoride copolymer and a method for producing the vinylidene fluoride copolymer, which are excellent in heat resistance, weather resistance, chemical resistance, and stain resistance, have good adhesion, and have reduced coloration during molding processing. It is to offer.

MEANS TO SOLVE THE PROBLEM As a result of earnestly researching in order to achieve the said objective, the present inventors found that the novel vinylidene fluoride copolymer which has the vinylidene fluoride monomeric unit and the methylidene malonic acid ester monomeric unit in a specific ratio can solve the problem. I found out. In addition, by hydrolyzing and modifying the ester portion of the vinylidene fluoride copolymer, it has been found that the vinylidene fluoride copolymer in which the ester portion is modified can be solved, and the modified vinylidene fluoride copolymer can solve the problem. .

That is, according to the present invention, 99.9 to 90 mol% of vinylidene fluoride monomer units represented by the formula (1), 0.1 to 10 mol% of methylidene malonic ester monomer units represented by the formula (2), and monomer units other than the monomer units 0 There is provided a vinylidene fluoride copolymer having a weight average molecular weight of 200,000 or more having from 10 mol%.

≪ Formula 1 >

(2)

(R ¹ and R ² are each independently H or an aliphatic hydrocarbon group having 1 to 5 carbon atoms, except that R ¹ and R ² are simultaneously H)

Furthermore, according to the present invention, in the vinylidene fluoride copolymer described above, a modified fluoride in which 10 to 90% of the total number of ester groups of the methylidene malonic ester monomer unit represented by the formula (2) is hydrolyzed. Vinylidene copolymer is provided.

Furthermore, according to the present invention, a monomer mixture containing 99.9 to 90 mol% of vinylidene fluoride, 0.1 to 10 mol% of methylidene malonic acid ester represented by the formula (3), and 0 to 10 mol% of other copolymerizable monomers, and polymerization The initiator is dispersed in an aqueous medium containing a dispersion stabilizer, and the polymerization reaction is performed by raising the temperature to a polymerization temperature equal to or higher than the decomposition temperature of the polymerization initiator,

99.9-90 mol% of vinylidene fluoride monomeric units represented by General formula (1), 0.1-10 mol% of methylidene malonic acid ester monomeric units represented by General formula (2), and 0-10 mol% of monomer units other than the said monomer unit, A method for producing a vinylidene fluoride copolymer having a weight average molecular weight of 200,000 or more is provided.

(3)

(R ¹ and R ² are each independently H or an aliphatic hydrocarbon group having 1 to 5 carbon atoms, except that R ¹ and R ² are simultaneously H)

Furthermore, according to the present invention, in the method for producing the vinylidene fluoride copolymer described above, an ester group of the methylidene malonic acid ester monomer unit represented by the formula (2) is further used, using an alkali metal halide or an alkali metal hydroxide. There is provided a method for producing a modified vinylidene fluoride copolymer that hydrolyzes 10 to 90% of the total number of.

The vinylidene fluoride copolymer of the present invention exhibits an effect of providing a vinylidene fluoride copolymer having excellent heat resistance, weather resistance, chemical resistance, and stain resistance, good adhesion, and reduced coloration during molding. . In addition, since the ester group derived from the methylidene malonic acid ester used as a comonomer with vinylidene fluoride is a functional group which reacted chemically, the vinylidene fluoride copolymer of this invention is based on the ester part, Chemical modification by reaction with a branched compound is possible, and the effect that a desired functional group can be introduce | transduced into a vinylidene fluoride copolymer is exhibited.

Moreover, the vinylidene fluoride copolymer of this invention exhibits the effect that it can manufacture easily by aqueous suspension polymerization.

1 is a synthesis scheme of dimethyl methylidene malate.
2 is a ¹ H-NMR spectrum of the vinylidene fluoride copolymer of Example 2. FIG.
3 is an IR spectrum of the vinylidene fluoride copolymer of Example 2. FIG.
4 is a graph of TGA pyrolysis curves of Example 1, Comparative Examples 1 and 2. FIG.
5 is a ¹ H-NMR spectrum of the vinylidene fluoride copolymer of Example 5. FIG.
6 is an IR spectrum of the vinylidene fluoride copolymer of Example 5. FIG.

1. Vinylidene Fluoride Copolymer

The novel vinylidene fluoride copolymer of the present invention comprises 99.9 to 90 mol% of vinylidene fluoride monomer units represented by the formula (1), 0.1 to 10 mol% of methylidene malonic ester monomer units represented by the formula (2), and the monomers. The vinylidene fluoride copolymer whose weight average molecular weight Mw which has 0-10 mol% of monomeric units other than a unit is 200,000 or more. The vinylidene fluoride copolymer of the present invention preferably has 99.9 to 92 mol% of vinylidene fluoride monomer units and 0.1 to 8 mol% of methylidene malonic acid ester monomer units, and more preferably 99.8 to vinylidene fluoride monomer units 94 mol% and 0.2 to 6 mol% of methylidene malonic acid ester monomeric units, more preferably 99.8 to 96 mol% of vinylidene fluoride monomeric units and 0.2 to 4 mol% of methylidene malonic acid ester monomeric units, particularly preferably fluorinated Vinylidene fluoride copolymer having 99.8 to 99 mol% of vinylidene monomer units and 0.2 to 1 mol% of methylidene malonic ester monomer units. When the vinylidene fluoride monomer unit is more than 99.9 mol%, the vinylidene fluoride monomer unit is closer to the homopolymer, and thus the adhesiveness with the metal is not good. On the other hand, when the vinylidene fluoride monomer unit is less than 90 mol%, heat resistance and chemical resistance This is insufficient and coloring may occur at the time of shaping | molding process.

Although the vinylidene fluoride copolymer of this invention has 99.9-90 mol% of said vinylidene fluoride monomeric units and 0.1-10 mol% of said methylidene malonic acid ester monomeric units, if necessary, monomers other than these monomeric units It may have 0-10 mol% of a unit (it may be called a "other monomeric unit."). In addition, these ratio is the ratio which computed the sum total of a vinylidene fluoride monomeric unit, the methylidene malonic acid ester monomeric unit, and another monomeric unit as 100 mol%. The other monomer unit is incorporated as a monomer unit of the vinylidene fluoride copolymer by copolymerizing with vinylidene fluoride and methylidene malonic acid ester using a monomer copolymerizable with vinylidene fluoride or methylidene malonic acid ester, as described later. You can. Therefore, in consideration of the physical properties and the properties of the vinylidene fluoride copolymer, the kind and ratio of the monomer units other than those incorporated into the monomer units of the vinylidene fluoride copolymer can be selected. Considering the heat resistance, weather resistance, chemical resistance, fouling resistance, adhesiveness, color reduction during molding, flexibility, and the like, which are the object of the present invention, the ratio of monomer units other than those incorporated into the monomer units of the vinylidene fluoride copolymer is 0. Although it is 10 mol%, Preferably it is 0.1-7 mol%, More preferably, it is 0.3-5 mol%, Especially preferably, it is 0.5-3 mol%. If the ratio of the other monomer units is less than 0.1 mol%, it has the same physical properties and properties as those of the vinylidene fluoride copolymer composed of only vinylidene fluoride monomer units and methylidene malonic acid ester monomer units, and most of the effects of incorporating other monomer units can be seen. I do not lose. On the contrary, when the ratio of another monomer unit exceeds 10 mol%, the physical property and the characteristic which the vinylidene fluoride copolymer of this invention aims for may be impaired.

Moreover, the weight average molecular weight of the vinylidene fluoride copolymer of this invention is 200,000 or more, Preferably it is 250,000 or more, More preferably, it is 260,000 or more, Especially preferably, it is 270,000 or more. If the weight average molecular weight is less than 200,000, sufficient mechanical strength may not be obtained. Although there is no upper limit in particular of the weight average molecular weight of a vinylidene fluoride copolymer, it is about 600,000 and is usually about 500,000. When the weight average molecular weight exceeds 600,000, the moldability may deteriorate or the solubility in a solvent may not be sufficient in the use used as a solution, and also the polymerization time will be prolonged remarkably and productivity will fall.

The number average molecular weight Mn of the vinylidene fluoride copolymer of the present invention is usually 90,000 to 300,000, preferably 100,000 to 250,000, and more preferably 110,000 to 200,000. If the number average molecular weight is less than 90,000, sufficient mechanical strength may not be obtained. If the number average molecular weight is more than 300,000, the moldability may deteriorate or the solubility in a solvent may not be sufficient in the use used as a solution. In addition, the polymerization time is remarkably prolonged and the productivity is lowered. Mw / Mn expressing the molecular weight distribution of the vinylidene fluoride copolymer of the present invention is usually 1.80 to 3.50, preferably 2.00 to 3.00, and more preferably 2.10 to 2.50. When Mw / Mn exceeds 3.50, the performance and moldability of molded products and the like are adversely affected. When Mw / Mn is less than 1.80, it is difficult to select molding processing conditions, or large spherical balls are generated during cooling during molding. There is a case.

In addition, the intrinsic viscosity (the logarithmic viscosity at 30 degrees C of the solution which melt | dissolved 4 g of polymers in 1 liter of N, N- dimethylformamide) of the vinylidene fluoride copolymer of this invention is 0.8-3.8 dl / g normally. . If the intrinsic viscosity is less than 0.8 dl / g, sufficient mechanical strength may not be obtained. If the intrinsic viscosity exceeds 3.8 dl / g, the moldability may deteriorate or the solubility in solvents may be lowered in applications used as a solution. In some cases, the polymerization time is remarkably prolonged and the productivity is lowered. The intrinsic viscosity varies depending on the purpose of use of the vinylidene fluoride copolymer, but for example, in a conventional injection molding or an extruded article, preferably 0.8 to 1.8 dl / g, more preferably 0.9 to 1.7 dl / g, particularly preferably about 0.95 to 1.5 dl / g. Moreover, in fiber products, such as a fishing line, Preferably it is 0.9-3.8 dl / g, More preferably, it is 1.0-3.7 dl / g, Especially preferably, it is about 1.1-3.5 dl / g.

The vinylidene fluoride copolymer of this invention has a vinylidene fluoride monomeric unit of General formula (1), the methylidene malonic ester monomeric unit of general formula (2), and another monomeric unit as needed. The monomer which forms the vinylidene fluoride monomeric unit of Formula (1) is vinylidene fluoride, and the monomer which forms the methylidene malonic ester monomer unit of Formula (2) is the methylidene malonic acid ester represented by Formula (3).

The monomer which forms the other monomeric unit which the vinylidene fluoride copolymer of this invention may have as needed is vinylidene fluoride or methyl, such as fluorine-containing monomers other than vinylidene fluoride, and hydrocarbon-type monomers, such as ethylene and a propylene. It is a monomer copolymerizable with a ridenmalonic acid ester (henceforth a "copolymerizable monomer"), and a preferable monomer is fluorine-containing monomers other than vinylidene fluoride. Specific examples thereof include vinyl fluoride, trifluoroethylene, chlorotrifluoroethylene, tetrafluoroethylene, hexafluoropropylene, fluoroalkyl vinyl ether, and the like.

The vinylidene fluoride copolymer of the present invention may have sufficient effects as long as any of random copolymers, block copolymers and graft polymers exhibits characteristics and characteristics according to the object of the present invention. It is preferable that it is a random copolymer from a point.

2. Methylidene malonic acid ester

The monomer which forms the methylidene malonic acid ester monomeric unit of General formula (2) is the methylidene malonic acid ester represented by General formula (3). In general formula (3), R <^1> and R <^2> is respectively independently H or a C1-C5 aliphatic hydrocarbon group, and contains diester and monoester of methylidene malonic acid. When R ¹ and R ² are simultaneously H, they are not included in the category of methylidene malonic acid ester represented by the formula (3). As R <^1> and R <^2> , since a stability is good and a polymer can be obtained in a short time, a methyl group, an ethyl group, and a propyl group are preferable. On the other hand, if R ¹ and R ² are aliphatic hydrocarbon groups having 6 or more carbon atoms, the volume of the ester moiety becomes large, and as a result, addition of vinylidene fluoride radicals to the methylidene malonic acid ester is inhibited, and the polymerization time is prolonged. Or no addition to methylidene malonic acid ester occurs, the polymerization proceeds only with vinylidene fluoride, and vinylidene fluoride homopolymer is obtained. Moreover, the effect of this invention can be acquired similarly not only to methylidene malonic acid ester but other alkylidene malonic acid ester, such as ethylidene malonic acid ester and propylidene malonic acid ester.

The methylidene malonic acid ester represented by General formula (3) can be obtained by a well-known manufacturing method itself. The present inventors have described, "A Versatile and Convenient Multigram Synthesis of Methylidenemalonic Acid Diesters" ("A widely applicable and useful multigram synthesis of methylidene malonic acid diesters"): De Keyser, J-L .; De Cock, C.J.C .; Poupaert, J. H .; Dumont, P., J. Org. Chem., 1988, 53, p.4859-4862), methylidene malonic acid dimethyl was synthesized by the reaction scheme of FIG.

(Synthesis of dimethyl methylidene malate)

a. Synthesis of intermediates

In a 500 ml three-necked flask equipped with a luggage lot cooling tube and a magnetic stirrer, 66.2 g (0.501 mol) of dimethyl malonic acid, 89.7 g (0.503 mol) of anthracene, 30.0 g of paraformaldehyde (1.00 mol of formaldehyde), copper acetate 5.00 g (25 mmol) of (II) -hydrate, 112 ml of acetic acid and 112 ml of xylene were added and heated to reflux for 24 hours. The crude product obtained after completion of the reaction was recrystallized with ethanol to obtain an intermediate compound as colorless needle crystals. Yield 107 g and yield 67%.

b. Synthesis of Methylidene Malonic Acid Dimethyl

In a 500 ml three-necked flask equipped with a luggage lot cooling tube and a magnetic stirrer, 40.0 g (0.124 mol) of the above-mentioned intermediate compound, 14.6 g (0.149 mol) of maleic anhydride, and 200 ml of liquid paraffin were added, under a nitrogen atmosphere of 225 ° C. And stirred for 1.5 hours. After the completion of the reaction, dimethyl methylidene malate was obtained as a colorless oil by distillation under reduced pressure (66-68 ° C / 10 hPa). Yield 12.4 g, yield 69%.

3. Preparation of Vinylidene Fluoride Copolymer

The vinylidene fluoride copolymer of this invention is a monomer containing at least 99.9-90 mol% of vinylidene fluorides, 0.1-10 mol% of the methylidene malonic ester represented by General formula (3), and 0-10 mol% of copolymerizable monomers. A mixture and a polymerization initiator can be manufactured by disperse | distributing to the aqueous medium containing a dispersion stabilizer, and performing a polymerization reaction.

Although the polymerization reaction can be carried out by suspension polymerization or emulsion polymerization, suspension polymerization is preferable for reasons such as ease of recovery of the vinylidene fluoride copolymer.

(1) monomer mixture

The monomer mixture is a monomer mixture containing at least 99.9 to 90 mol% of vinylidene fluoride, 0.1 to 10 mol% of methylidene malonic acid ester represented by the formula (3), and 0 to 10 mol% of copolymerizable monomers.

The ratio of vinylidene fluoride and methylidene malonic acid ester in the monomer mixture is 99.9 to 90 mol% of vinylidene fluoride and 0.1 to 10 mol% of methylidene malonic acid ester, preferably 99.9 to 92 mol of vinylidene fluoride % And 0.1 to 8 mol% of methylidene malonic acid ester, more preferably 99.8 to 94 mol% of vinylidene fluoride and 0.2 to 6 mol% of methylidene malonic acid ester, more preferably 99.8 to 96 mol% of vinylidene fluoride, and 0.2 to 4 mol% of methylidene malonic acid ester, particularly preferably 99.8 to 99 mol% of vinylidene fluoride and 0.2 to 1 mol% of methylidene malonic acid ester.

Moreover, the ratio of the copolymerizable monomer is a range which does not adversely affect heat resistance, weather resistance, chemical resistance, fouling resistance, adhesiveness, moldability, mechanical properties, etc., and is a range which does not inhibit a polymerization reaction, vinylidene fluoride, In the monomer mixture consisting of the methylidene malonic acid ester represented by the general formula (3) and the copolymerizable monomer, it is preferably 0.1 to 7 mol%, more preferably 0.3 to 5 mol%, particularly preferably 0.5 to 3 mol%. . In addition, these ratio is the ratio which calculated the sum total of a vinylidene fluoride monomeric unit, the methylidene malonic acid ester monomeric unit, and another monomeric unit in 100 mol%, and shows the vinylidene fluoride, methylidene malonic acid ester, and the copolymerizable monomer of In consideration of the polymerization reactivity, an optimal range may be selected.

(2) Polymerization initiator

As the polymerization initiator, those having a half-life temperature T ₁₀ of 10 hours to 30 ° C (corresponding to a critical temperature of almost vinylidene fluoride) to 90 ° C are preferably used, diisopropylperoxydicarbonate (T ₁₀ = 40.5 ° C), di-n-propyl peroxydicarbonate there may be mentioned a (T ₁₀ = 40.3 ℃), fur-butyl peroxypivalate (T ₁₀ = 54.6 ℃), are used by properly selected according to the desired polymerization temperature. The amount of the polymerization initiator used is preferably as low as possible in order to obtain a vinylidene fluoride copolymer having good thermal stability. However, when the amount is too small, the polymerization time becomes extremely long, so the amount of the monomer mixture is in the range of 0.01 to 2% by mass with respect to the amount of the monomer mixture. It is preferable, More preferably, it is 0.05-1.5 mass%, More preferably, it is the range of 0.1-1.2 mass%. When a polymerization initiator exceeds 2 mass%, it becomes difficult to use it effectively in a polymerization reaction, and it exists in the tendency for the high temperature coloring resistance and the elution property of the resultant polymer to deteriorate.

(3) dispersion stabilizer

As a dispersion stabilizer, when performing emulsion polymerization as a polymerization reaction, a general purpose fluorine-type emulsifier can be used. In addition, when performing suspension polymerization as a polymerization reaction, the suspension agent used for normal suspension polymerization can be used, A partially saponified polyvinyl acetate, methyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxypropyl methyl cellulose, etc. Water-soluble polymers, such as a water-soluble cellulose ether, an acrylic acid polymer, and gelatin, can be illustrated. The amount of the suspending agent is usually used in an amount of 0.01 to 2% by mass, preferably 0.01 to 1% by mass, and more preferably 0.05 to 0.5% by mass relative to the amount of the monomer mixture.

(4) aqueous medium

As the aqueous medium, ordinary ion-exchanged water, distilled water or ultrapure water can be used. As for the usage-amount of an aqueous medium, the ratio (mass ratio) of an aqueous medium / monomer mixture is normally 1 / 1-10 / 1, Preferably it is 1.5 / 1-8 / 1, More preferably, it is 2 / 1-6 / 1 And particularly preferably in the range of 2.5 / 1 to 5/1. If the ratio of the aqueous medium / monomer mixture is less than 1/1, stirring, heat removal, and particle size control become difficult. Moreover, when the said ratio exceeds 10/1, there exists a problem that manufacturing efficiency falls.

In an aqueous medium, you may use together a small amount of halogenated hydrocarbon solvents. For example, monohydropenta fluorodichloropropane, in particular 1,1,1,2,2-pentafluoro-3,3-dichloropropane, 1,1,2,2,3-pentafluoro-1, When 3-dichloropropane or a mixture thereof is used together, the usage-amount of a polymerization initiator can be reduced. These halogenated hydrocarbon solvents can use 10-50 mass parts, Preferably 15-40 mass parts with respect to 100 mass parts of aqueous media.

(5) use of chain transfer agents

When manufacturing the vinylidene fluoride copolymer of this invention by suspension polymerization, it is preferable to use a chain transfer agent for the purpose of adjusting the molecular weight of the copolymer obtained. Examples of chain transfer agents include acetone, isopropyl acetate, ethyl acetate, diethyl carbonate, dimethyl carbonate, ethyl carbonate, propionic acid, trifluoro acetic acid, trifluoroethyl alcohol, formaldehyde dimethyl acetal, 1,3-butadiene epoxide, Although 1, 4- dioxane, (beta)-butyl lactone, ethylene carbonate, vinylene carbonate, etc. are mentioned, It does not lower molecular weight or intrinsic viscosity effectively, and also does not inhibit the thermal stability of vinylidene fluoride copolymer. In consideration of the thing, the availability, and the ease of handling, acetone, ethyl acetate, and diethyl carbonate are more preferable, and ethyl acetate and diethyl carbonate are particularly preferable. The amount of the chain transfer agent to be used is 0.05 to 5% by mass, preferably 0.1 to 3% by mass, more preferably 0.1 to 1% by mass, still more preferably 0.15 to 0.5% by mass relative to the monomer mixture.

In addition, phosphite compounds, phenol compounds, hydroxides or oxides of Mg or Zn and the like can be mixed as color inhibitors or stabilizers.

(6) polymerization reaction

In order to manufacture the vinylidene fluoride copolymer of this invention by suspension polymerization method, the vinylidene fluoride (threshold temperature Tc = 30.1 degreeC, critical pressure Pcr = 4.38 Mpa) 99.9-90 mol%, the methylidene malonic acid ester of General formula (3) 100 parts by mass of a mixture of 0.1 to 10 mol% and 0 to 10 mol% of a copolymerizable monomer (hereinafter referred to as a “monomer mixture”) is 100 to 1000 parts by mass of an aqueous medium, preferably 150 to 800 parts by mass, more preferably. Preferably it is dispersed in 200 to 600 parts by mass, particularly preferably 250 to 500 parts by mass, and the temperature is raised to the polymerization temperature to initiate suspension polymerization.

The polymerization temperature T (℃) is, but more than the decomposition temperature of the polymerization initiator, with respect to the T ₁₀ of the polymerization initiator, it is preferable to set at a temperature satisfying the condition of T ₁₀ -25≤T≤T ₁₀ +25, more preferably Advantageously the T ₁₀ -20≤T≤T ₁₀ +20, more preferably a temperature satisfying the condition of T ₁₀ -15≤T≤T ₁₀ +15. When the polymerization temperature T is lower than T ₁₀ -25, since the rate of radical generation from the polymerization initiator is slow, the rational productivity of the polymer (for example, the polymer yield described below within 30 hours of polymerization time (hereinafter, simply referred to as "yield") In order to secure 70 mol% or more), the amount of the polymerization initiator is inevitably increased. As a result, the polymerization initiator and the residue which do not contribute to superposition | polymerization remain in a polymer, and deteriorate coloring resistance and low elution. On the other hand, when the polymerization temperature T is higher than T ₁₀ +25 (° C.), a rapid decrease in the polymerization rate occurs during the polymerization, and the polymerization must be stopped in the middle, and the color resistance of the vinylidene fluoride copolymer formed as a result is achieved. Also worsens. It is thought that this is because the rate of radical generation is too fast, contributing to the polymerization of the monomer mixture, and increasing side reactions such as disproportionation reactions and hydrogen drawing reactions between radicals.

The end point of the polymerization reaction is appropriately selected in consideration of the balance between the reduction of the amount of unreacted monomers and the prolongation of the polymerization time, that is, the productivity of the copolymer obtained. In general, when the polymerization temperature is high, the polymerization time is short. On the other hand, when the polymerization temperature is low, the polymerization time is long. In the present invention, the polymerization time is usually 1 hour or more, preferably 3 hours or more, more preferably 5 hours or more, and usually within 40 hours, preferably within 35 hours, more preferably within 30 hours. More preferably within 25 hours. The polymer yield at the time of completion of polymerization (in the monomer mixture containing vinylidene fluoride, methylidene malonic acid ester and the copolymerizable monomer to be used if necessary, refers to expressing the percentage of monomers copolymerized as a percentage) is usually 70 mol% or more, Preferably it is 75 mol% or more, More preferably, it is 80 mol% or more. If the yield is less than 70 mol%, the ratio of the monomer units in the vinylidene fluoride copolymer obtained may be different from the ratio of the monomer units in the vinylidene fluoride copolymer specified in the present invention. The larger the yield is, the longer the polymerization time is, and therefore, in consideration of manufacturing constraints, about 95 mol% is the upper limit, and preferably 93 mol% is the upper limit, and usually 90 mol% is used as the yield. It is the upper limit.

After completion of the polymerization reaction, the aqueous slurry containing the copolymer is heated to inactivate the polymerization initiator, and then the copolymer is filtered off, dehydrated, washed with water and dried to obtain a powder of the copolymer. The powder of the copolymer thus obtained has a 50% cumulative value (D50) in the particle size cumulative distribution as measured by the dry body fractionation method in accordance with the average particle diameter (JIS (Japanese Industrial Standard. The average particle diameter shown) is 30 to 250 m, preferably 40 to 230 m, more preferably about 50 to 200 m, and the bulk density is 0.30 to 0.80 g / cm 3, preferably 0.35 to 0.80 g / cm 3 More preferably, it is about 0.37-0.75 g / cm <3>, and handling property is favorable.

The vinylidene fluoride copolymer of this invention is a novel vinylidene fluoride copolymer obtained by copolymerizing vinylidene fluoride, methylidene malonic acid ester, and the monomer copolymerizable as needed.

The obtained polymer is a copolymer containing a methylidene malonic acid ester polymer unit, and a signal derived from C = O stretching vibration of the methylidene malonic acid ester is observed in the IR spectrum (for example, methylidene malonic acid) In the diester, the signal of the proton derived from -COOCH ₂ -of methylidene malonic acid ester is observed in 1740 cm ⁻¹ vicinity (1740 ± 10 cm ⁻¹ ) and ¹ H-NMR spectrum For example, in the methylidene malonic acid diester, it confirmed by 3.7 ppm vicinity (3.7 ± 0.5 ppm) observed. The ratio of the vinylidene fluoride unit and the methylidene malonic ester unit contained in the vinylidene fluoride copolymer is calculated by the area ratio in the ¹ H-NMR spectrum.

4. Properties and Properties of Vinylidene Fluoride Copolymer

As for the vinylidene fluoride copolymer of this invention, melting | fusing point (Tm) normally measured by differential scanning calorimetry (DSC) exists in the range of 130-185 degreeC, Preferably it exists in the range of 163-177 degreeC. In addition, the crystallization temperature measured (Tc. Refers to the crystallization temperature measured during the cooling process) is in the range of 100 to 145 ° C, and preferably in the range of 131 to 137 ° C. In particular, as the vinylidene fluoride copolymer of the present invention, a melting point is in the range of 172 to 176 ° C and a crystallization temperature is in the range of 131 to 137 ° C. In this case, both the melting point and the crystallization temperature are equivalent to the vinylidene fluoride homopolymer (about 174 ° C melting point and about 136 ° C crystallization temperature). It can be molded.

The vinylidene fluoride copolymer of this invention has a vinylidene fluoride monomeric unit, a methylidene malonic acid ester monomeric unit, and another monomeric unit as needed, and a monomeric unit other than being incorporated in a vinylidene fluoride copolymer as needed. By adjusting the type and ratio thereof, the physical properties and properties of the vinylidene fluoride copolymer can be designed in accordance with the intended use.

That is, the vinylidene fluoride copolymer of the present invention having characteristics such as heat resistance, weather resistance, chemical resistance, fouling resistance, adhesiveness, color reduction during molding processing, flexibility, and the like, and particularly characterized by heat resistance, flexibility, or molding The vinylidene fluoride copolymer according to the objective, such as having the characteristic in color reduction of a city, can be provided.

For example, as desired, a vinylidene fluoride copolymer having a melting point of about 130 to 168 ° C, preferably about 140 to 167 ° C, or a vinylidene fluoride copolymer having a melting point of about 178 to 185 ° C can be obtained. Moreover, various vinylidene fluoride copolymers whose crystallization temperature is about 100-120 degreeC, about 125-133 degreeC, or about 140-145 degreeC can also be obtained as desired.

The vinylidene fluoride copolymer of this invention is equipped with the coloring resistance equivalent to vinylidene fluoride homopolymer. That is, with respect to the yellow index measured by the method according to ASTM D1925, YI. The larger the yellow color is, the YI of the vinylidene fluoride copolymer of the present invention is less than 0 (negative), and the fluorination of the present invention The difference (absolute value) between YI of a vinylidene copolymer and YI of a vinylidene fluoride homopolymer is 30 or less normally, Preferably it is 25 or less, More preferably, it is 20 or less.

Moreover, the vinylidene fluoride copolymer of this invention can be equipped with the thermal decomposition resistance equivalent to vinylidene fluoride homopolymer. That is, the difference (absolute value) of the thermal decomposition weight change rate between the vinylidene fluoride copolymer of the present invention and the vinylidene fluoride homopolymer of the present invention is usually within 0.3% with respect to the residual amount of pyrolysis at 300 ° C in thermogravimetric analysis (TGA). Preferably, it can be made into 0.2% or less, More preferably, it can be made into 0.1% or less.

Moreover, the vinylidene fluoride copolymer of this invention is equipped with the adhesiveness outstanding compared with the vinylidene fluoride homopolymer. Specifically, peeling strength with copper foil measured by 180 ° peel test according to JIS K6854 is 1.2 times or more, preferably 1.4 times or more, more preferably 1.5 times the peeling strength of vinylidene fluoride homopolymer. That's it. Although the upper limit of peeling strength differs according to the kind and usage-amount of the methylidene malonic acid ester to be used, it is about 4.0 times, Considering the balance with the other characteristic of a vinylidene fluoride copolymer, it is usually 3.5 times, Preferably it is Up to 3.0 times is useful.

5. Chemical Modification of Vinylidene Fluoride Copolymer

The vinylidene fluoride copolymer of the present invention is capable of chemical modification by reaction with various compounds, with the ester group being a chemically reactive active group as a starting point of a chemical reaction. As described above, there have been reports of vinylidene fluoride copolymers containing ester groups until now, but as described above, since the heat resistance, in particular, the coloring resistance was difficult, the range of applicable reaction conditions was narrow. Since the vinylidene fluoride copolymer of this invention has few restrictions in setting reaction conditions as a result of the heat resistance being improved, it is useful.

As an example of chemical modification from the vinylidene fluoride copolymer of this invention, derivation to a carboxylic acid modified vinylidene fluoride copolymer by hydrolysis of an ester group is mentioned. MEANS TO SOLVE THE PROBLEM As a result of earnest research, carboxylate ester is made by reacting the vinylidene fluoride copolymer of this invention with alkali metal halides or alkali metal hydroxides, such as lithium bromide, lithium iodide, lithium hydroxide, or sodium bromide. 10 to 90% of the total number of ester groups of the monomer units of the methylidene malonic acid ester of the vinylidene fluoride copolymer are hydrolyzed by making the carboxylic acid alkali metal salt and then hydrolyzing the obtained carboxylic acid alkali metal salt. The carboxylic acid modified vinylidene fluoride copolymer formed by decomposition was obtained. In the carboxylic acid-modified vinylidene fluoride copolymer in which less than 10% of the total number of ester groups of the methylidene malonic ester ester is hydrolyzed, the total number of ester groups of the monomer units of methylidene malonic ester Since almost all of, remain unchanged from the physical properties and properties of the vinylidene fluoride copolymer before modification. Moreover, since the carboxylic acid modified vinylidene fluoride copolymer formed by hydrolyzing more than 90% of the total number of ester groups which the monomeric unit of methylidene malonic acid ester has requires a long time in order to perform a modification reaction, it is not practical. little. Therefore, as long as the ratio of the ester group which the monomeric unit of the methylidene malonic acid ester is hydrolyzed in the range of 10 to 90% can be designed according to a use purpose. For example, a carboxylic acid-modified vinylidene fluoride copolymer having characteristics for improving adhesion can be obtained by setting the proportion of the ester group to be hydrolyzed to about 35 to 90%, preferably about 40 to 85%.

As the chemical modification from the vinylidene fluoride copolymer of the present invention, other general reactions of carbonyl groups are also applicable, and formation of acetals, amides, alcohols by addition reactions, and induction into double bonds by wittig reactions is possible. When the vinylidene fluoride copolymer of the present invention is used, various functional group-modified vinylidene fluoride copolymers can be obtained.

Since vinylidene fluoride is a monomer that is difficult to cause copolymerization with other vinyl monomers and is difficult to predict copolymerization, the vinylidene fluoride copolymer of the present invention can also be evaluated as an important intermediate for obtaining an organic functional group modified vinylidene fluoride copolymer. Can be.

The functional group-modified vinylidene fluoride copolymer using the vinylidene fluoride copolymer of the present invention is a member of films, sheets, fibers, containers, office equipment, and electronic devices by a general melt molding method such as injection molding, extrusion molding or compression molding. It can be used for manufacture of various molded articles, etc., and since it can especially improve the adhesiveness by functional group modification, it can expect that it is widely used in the field of binders, paints, etc.

[Example]

Hereinafter, although an Example and a comparative example are given and this invention is demonstrated more concretely, this invention is not limited to these Examples.

The measuring method of the physical property and the characteristic of the vinylidene fluoride copolymer (the homopolymer in the case of the comparative example 1) of an Example and a comparative example is as follows.

(1) intrinsic viscosity

Intrinsic viscosity means logarithmic viscosity at 30 degreeC of the solution which melt | dissolved 4 g of vinylidene fluoride copolymers in 1 liter of N, N- dimethylformamide (DMF). The sample for a measurement was prepared by adding 20 ml of DMF to 80 mg of the polymer, and heating and dissolving at 70 ° C for 2 hours. The measurement of intrinsic viscosity was performed at 30 degreeC using the Ube-rod viscometer by the Kusano Kagaku company.

(2) weight average molecular weight and number average molecular weight

The weight average molecular weight and the number average molecular weight were measured using GPC (gel permeation chromatography), and polystyrene was computed as a standard sample.

The sample for measurement of GPC was prepared by dissolving vinylidene fluoride copolymer (10 mg in 10 ml of a 10 mM LiBr-NMP solution at a concentration of 10 mg), and produced by Nippon Bunko Chemical Co., Ltd. GPC-900 (column; Showa Denko Co., Ltd.) Kasei Shodex KD-806M) was used, and the measurement was carried out at a flow rate of 1 ml / min and a measurement temperature of 40 ° C.

(3) melting point and crystallization temperature

The melting point (Tm) and crystallization temperature (Tc) of the vinylidene fluoride copolymer were measured by differential scanning calorimetry (DSC).

The sample for measurement of DSC was preheated at 210 degreeC for 30 second using the press molding machine (AYSR-5 by the Corporation | KKK), hold | maintained at press pressure of 0.5 Mpa for 1 minute, and the press sheet was produced, From this, about 10 mg was cut out and produced. DSC measurement was carried out using a METTLER company DSC30, temperature rising and cooling at a rate of 10 ℃ / min in a nitrogen atmosphere in the range of 30 to 220 ℃, melting point (Tm) from the endothermic peak temperature in the temperature rising process ), And the crystallization temperature (Tc) was determined from the exothermic peak temperature in the cooling process.

(4) pyrolysis loss

The loss of thermal decomposition of the vinylidene fluoride copolymer was measured by thermogravimetric analysis (TGA).

The sample for measurement of TGA is produced by cutting out about 20 mg of the sample from the press sheet produced previously as a sample for measurement of DSC, and it is 10 degreeC in nitrogen atmosphere using the thermogravimetric analyzer (TGA / SDTA851 by METTLER TOLEDO). The temperature was raised at a rate of / min, and the pyrolysis loss of the sample was measured.

(5) nuclear magnetic resonance (NMR) spectra

The measurement of the NMR spectrum of the vinylidene fluoride copolymer was performed using the AVANCE AC 400FT NMR spectrum meter by Bruker Co., Ltd. directly using commercially available heavy DMF as a measurement solvent.

(6) infrared absorption (IR) spectrum

The sample for IR spectrum measurement of the vinylidene fluoride copolymer was produced with the press film of thickness about 0.05 mm by the press molding machine (AYSR-5 by the Corporation | KKK). The IR spectrum was measured using FT-730 manufactured by HORIBA (Horiba, Ltd.).

(7) yellow index (YI)

The sample for measurement of the YI of the vinylidene fluoride copolymer was preheated at 240 ° C. for 6 minutes using a press molding machine (AYSR-5, manufactured by KK Shoshin Co., Ltd.), and then held at a press pressure of 10 MPa for 2 minutes. It produced by the 11 x 6.4 x 0.6 cm test piece.

The measurement of YI was measured by the method according to ASTMD1925 using the Nippon Denshoku Kogyo Co., Ltd. color meter ZE6000. The larger the value of YI, the stronger the yellow color.

(8) Measurement of peel strength

As an electrode composition, each sample which gives a composition of 96 parts of artificial graphite (MCMB25-28 by Osaka Chemical Co., Ltd.) and 4 parts of vinylidene fluoride copolymers is disperse | distributed in solvent NMP, and the electrode slurry of 63 mass% of solid content concentration is manufactured. Then, it coated on the 10-micrometer-thick Cu foil with the bar coater, it dried at 110 degreeC for 30 minutes, and produced the single-side coating electrode which is 150 g / m <2> in weight per single side unit area.

The single-side coating electrode obtained above was cut out to 50 mm in length and 20 mm in width, and was flat-pressed at room temperature and press pressure 0.8 t / cm <2>, and it was set as the test piece. Gum tape was affixed on the coating electrode surface, and Cu foil was 180 at a head speed of 200 mm / min using a tensile tester (STA-1150 UNIVERSAL TESTING MACHINE manufactured by ORIENTEC Co., Ltd.) in accordance with JIS K6854. The peeling test was done and peeling strength was measured.

[polymerization]

Example 1 (vinylidene fluoride / methylidene malonic acid dimethyl = 99/1 (mass ratio))

In a 2-liter autoclave, 1024 g of ion-exchanged water, 0.6 g of methyl cellulose, 1.2 g of ethyl acetate, 8.6 g of 50 wt% diisopropyl peroxydicarbonate-freon 225 cb solution, vinylidene fluoride (VDF) 396 g and 4.0 g of methylidene malonic acid were added, and suspension polymerization was performed for 22 hours until the pressure dropped to 1.5 MPa at 29 ° C. After completion of the polymerization, the polymer slurry was heat-treated at 95 ° C. for 30 minutes, the polymerization initiator was inactivated, the polymer was separated by filtration, dewatered and washed with water, and further dried at 80 ° C. for 20 hours to obtain a polymer powder. The yield was 86% and the intrinsic viscosity of the obtained polymer was 1.29 dl / g.

[Examples 2 to 4, Comparative Examples 1 to 3]

Examples 2-4 and Comparative Examples 1-3 were the same methods as Example 1 except having changed the vinylidene fluoride (VDF), comonomer ratio, and the kind of comonomer as shown in Table 1. Done. In addition, Comparative Example 1 is a homopolymer of vinylidene fluoride.

In addition, the copolymer of methylidene malonic acid ester is obtained from COOCH ₂ R in the ¹ H-NMR spectrum of the obtained polymer as shown in FIG. 2 and FIG. 3 with respect to Example 2. 1, 2, 4, R = H in Comparative Examples 2 and 3, R = Me) in Example 3 are observed at around 3.7 ppm, and signals derived from C = O stretching vibration in the IR spectrum It confirmed by having observed around 1740 cm <^-1> . The ratio of the vinylidene fluoride units and methyl Li denmal acid ester units contained in the vinylidene fluoride copolymer (molar ratio) is calculated by the area ratio of the ¹ H-NMR spectrum. In addition, the ratio of the chlorotrifluoroethylene unit was computed from the chlorine concentration measured by the oxygen flask combustion method.

[Various physical properties]

Table 2 summarizes various physical properties and properties of the polymers obtained in Examples 1 to 4 and Comparative Examples 1 to 3.

As for the vinylidene fluoride copolymer of this invention of Examples 1-3, melting | fusing point and crystallization temperature have only a difference of 1-2 degreeC compared with the vinylidene fluoride homopolymer of the comparative example 1, and maintain almost equivalent heat resistance and moldability. Doing. In addition, the vinylidene fluoride copolymer of the present invention having another monomer unit of Example 4 has a high melting point at 165 ° C and practically heat resistance, and a crystallization temperature of 131 ° C, which is relatively low. The copolymer which can be used for manufacture of highly molded articles and the use which requires the flexibility was obtained.

As for the vinylidene fluoride copolymer of this invention of Examples 1-4, the difference with the vinylidene fluoride homopolymer of Comparative Example 1 is 12.8 to 19.9, and is a negative value with respect to the value of YI which shows coloration resistance. In this regard, the coloration resistance is also at a sufficient level.

In addition, as shown in the TGA pyrolysis curve of FIG. 4, the vinylidene fluoride copolymer of Example 1 reduced the weight to the same degree as the homopolymer of vinylidene fluoride of Comparative Example 1 even by heating exceeding 300 ° C. Is less and has excellent heat resistance equivalent to vinylidene fluoride homopolymer. Moreover, the peeling strength of the coating electrode and copper foil which use the vinylidene fluoride copolymer of Example 1 as a binder was measured by the 180 degree peeling test according to JIS K6854, and it is 4.14 gf / mm, and the comparative example 1 It was found that when the homopolymer of vinylidene fluoride of B was used as the binder, it was larger than 2.45 gf / mm (1.69 times), and an improvement was also observed in adhesion. In addition, Example 4 is the vinylidene fluoride copolymer of this invention which has chlorotrifluoroethylene as another monomer. It is known that copolymerization of vinylidene fluoride with chlorotrifluoroethylene can reduce the crystallinity, and is applicable to applications where flexibility is more important than high heat resistance. Examples of applications requiring such flexibility include a tube (for example, Japanese Patent Application Laid-Open No. 6-73135; US Pat. No. 5,292,816) and a polymer gel electrolyte (for example, Japanese Patent Application Laid-Open No. 11-66949). It can be illustrated.

On the other hand, the vinylidene fluoride copolymer copolymerized with maleic acid ester of Comparative Examples 2 and 3 is almost equivalent to the homopolymer in Tm and Tc, but since the value of YI shows a large plus, the color resistance is inferior and practical. Lacked. Moreover, when the vinylidene fluoride copolymer of the comparative example 2 exceeds 300 degreeC from the TGA pyrolysis curve of FIG. 4, a rapid weight loss generate | occur | produces.

The detailed reason why the vinylidene fluoride copolymer of the present invention is superior to other organic functional group-modified vinylidene fluoride copolymers in color resistance is unclear at this time, but it is due to the fact that the ester group is bonded to the same carbon atom. It is assumed that the arrangement of the ester group has an important effect on the heat resistance.

[Hydrolysis of Ester Part]

[Example 5]

125 ml of N, N-dimethylformamide and 1.17 g of lithium bromide were placed in a 500 ml three-necked flask equipped with a magnetic stirrer and a Jimlot cooling tube. 5.05 g of the vinylidene fluoride copolymer of the present invention obtained in Example 2 was added to this solution, and the mixture was heated and stirred at 100 ° C for 9 hours. After cooling to room temperature, the reaction solution was reprecipitated using dilute hydrochloric acid. The obtained solid was separated by filtration, dewatered and washed with water, and further dried at 80 ° C for 20 hours. As a result of measuring the ¹ H-NMR spectrum of the obtained solid, it was found that about 41% of the total number of ester groups in the copolymer was hydrolyzed from the change in the integral value of the signal (nearly 3.7 ppm) attributed to COOCH ₃ . It confirmed (refer FIG. 5 and FIG. 6).

The physical properties of the obtained modified vinylidene fluoride copolymer are shown in Table 3, and it was found that they had a melting point and crystallization temperature equivalent to those of the modified vinylidene fluoride copolymer before the modification of Example 2. For this reason, it is estimated that the modified vinylidene fluoride copolymer can perform various chemical modifications, maintaining the excellent heat resistance equivalent to the homopolymer of vinylidene fluoride and the vinylidene fluoride copolymer before modification.

The vinylidene fluoride copolymer having the vinylidene fluoride monomer unit and the methylidene malonic acid ester monomer unit of the present invention is excellent in heat resistance, weather resistance, chemical resistance and fouling resistance, has good adhesiveness, and coloration during molding processing Since it reduces, it can be expected to be widely used in the field of various molded articles, binders, paints, etc.

In addition, since the ester group of the vinylidene fluoride copolymer of the present invention is a chemically reactive functional group, various chemical modifications can be made by using the ester group as a starting point of a chemical reaction, thereby solving a wider field and problem. It can be expected to apply to.

In addition, since the vinylidene fluoride copolymer of this invention can be manufactured by the suspension polymerization method which employ | adopted the conditions similar to the prior art without requiring installation of a special manufacturing facility, etc., it has a wider field and It can be expected to be applied to the solution of the problem.

Claims (10)

99.9 to 90 mol% of vinylidene fluoride monomer units represented by the formula (1), 0.1 to 10 mol% of methylidene malonic ester monomer units represented by the formula (2), and 0 to 9.9 mol% of monomer units other than the monomer units, Vinylidene fluoride copolymer having a weight average molecular weight of 200,000 or more.
&Lt; Formula 1 >

(2)

(R ¹ and R ² are each independently H or an aliphatic hydrocarbon group having 1 to 5 carbon atoms, except that R ¹ and R ² are simultaneously H) The vinylidene fluoride copolymer according to claim 1, wherein the melting point is in the range of 163 to 177 ° C. The vinylidene fluoride copolymer of Claim 1 whose peeling strength is 1.2 times or more of the vinylidene fluoride homopolymer which does not have a methylidene malonic acid ester monomeric unit. The vinylidene fluoride copolymer of Claim 1 whose R <^1> and R <^2> is a methyl group. The vinylidene fluoride copolymer of Claim 1 whose R <^1> and R <^2> is an ethyl group. The modified vinylidene fluoride copolymer according to claim 1, wherein 10 to 90% of the total number of ester groups of the methylidene malonic ester monomer unit represented by the formula (2) is hydrolyzed. . A monomer mixture containing 99.9 to 90 mol% of vinylidene fluoride, 0.1 to 10 mol% of methylidene malonic acid ester represented by the formula (3), and 0 to 9.9 mol% of other copolymerizable monomers, and a polymerization initiator, It disperse | distributes to the aqueous medium to contain, and it raises to the polymerization temperature more than the decomposition temperature of a polymerization initiator, and performs a polymerization reaction,
99.9 to 90 mol% of vinylidene fluoride monomer units represented by the formula (1), 0.1 to 10 mol% of methylidene malonic ester monomer units represented by the formula (2), and 0 to 9.9 mol% of monomer units other than the monomer units, The manufacturing method of the vinylidene fluoride copolymer whose weight average molecular weight is 200,000 or more.
(3)

(R ¹ and R ² are each independently H or an aliphatic hydrocarbon group having 1 to 5 carbon atoms, except that R ¹ and R ² are simultaneously H)
&Lt; Formula 1 >

(2)

(R ¹ and R ² are each independently H or an aliphatic hydrocarbon group having 1 to 5 carbon atoms, except that R ¹ and R ² are simultaneously H) The manufacturing method of the vinylidene fluoride copolymer of Claim 7 whose said polymerization temperature is the temperature which satisfy | fills following formula 4.
&Quot; (4) &quot;
T ₁₀ -25≤T≤T ₁₀ +25
(Where T means polymerization temperature (° C.) and T ₁₀ means 10 hour half-life temperature (° C.) of the polymerization initiator) The manufacturing method of the vinylidene fluoride copolymer of Claim 7 whose polymer yield at the time of completion | finish of a polymerization reaction is 70 mol% or more. In the manufacturing method of the vinylidene fluoride copolymer of Claim 7, Furthermore, using the alkali metal halide or alkali metal hydroxide, the number of the total number of ester groups which the methylidene malonic ester monomer unit represented by General formula (2) has is The manufacturing method of the modified vinylidene fluoride copolymer which hydrolyzes 10 to 90%.

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