Resin composition and molded body

Abstract

[Problem] To provide a resin composition and molded body including a vinylidene fluoride polymer which has outstanding transparency and is capable of preventing generation of hydrogen fluoride during molding. [Solution] A resin composition containing a vinylidene fluoride polymer, a quaternary organic salt, and an antioxidant, wherein the antioxidant contains at least one of a phosphonic acid-based compound and a phosphite-based compound having a specific structure. The molded body contains the resin composition.

Description

Resin composition and molded article

[0001] The present invention relates to a resin composition and molded article containing a vinylidene fluoride polymer.

[0002] Vinylidene fluoride resins, including polyvinylidene fluoride polymers, are used in various fields due to their high strength, chemical resistance, heat resistance, and ferroelectric properties. Patent Document 1 discloses a polyvinylidene fluoride resin containing polyvinylidene fluoride polymer and alkyl quaternary ammonium bisulfate, which is one of the quaternary organic salts. Vinylidene fluoride resins containing alkyl quaternary ammonium bisulfate exhibit excellent transparency and are expected to be used in a wide range of fields, including applications in optical components.

[0003] Japanese Patent Application Publication No. 11-323052

[0004] However, resin compositions containing vinylidene fluoride polymer and alkyl quaternary ammonium sulfate decompose at relatively low temperatures, potentially generating hydrogen fluoride during melt molding. This hydrogen fluoride generation could lead to problems such as deterioration of the molding machine.

[0005] Therefore, there is a need for resin compositions and molded articles containing a vinylidene fluoride polymer that has excellent transparency and can suppress the generation of hydrogen fluoride during molding.

[0006] The following is provided by this disclosure: (1) a vinylidene fluoride polymer, a quaternary organic salt, and an antioxidant, wherein the antioxidant is a phosphonic acid compound or the following formula (1) [In formula (1), R ａ and R ｂA resin composition comprising at least one of phosphite compounds represented by [where is a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms or a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, which are the same or different from each other]. (2) The resin composition according to (1), wherein the quaternary organic salt comprises a quaternary ammonium salt or a quaternary phosphonium salt. (3) The resin composition according to (1) or (2), wherein the phosphite compound comprises one or more selected from the group consisting of O,O'-dialkyl(C1-C18) pentaerythritol diphosphite, 3,9-bis(2,6-di-tert-butyl-4-methylphenoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane, 3,9-bis(2,4-di-tert-butylphenoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane, and 3,9-bis[2,4-bis(1-methyl-1-phenylethyl)phenoxy]-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane. (4) The resin composition according to any one of (1) to (3), wherein the phosphonic acid compound comprises one or more selected from the group consisting of phosphonic acid, linear alkylphosphonic acid (having 1 to 18 carbon atoms), vinylphosphonic acid, allylphosphonic acid, (2-bromoethyl)phosphonic acid, (2-chloroethyl)phosphonic acid, phenylphosphonic acid, (4-hydroxyphenyl)phosphonic acid, (carboxymethyl)phosphonic acid, (2-phenylethyl)phosphonic acid, aminomethylphosphonic acid, and (1-aminoethyl)phosphonic acid. (5) The resin composition according to any one of (1) to (4), wherein the quaternary organic salt is contained in an amount of 0.1 to 5 parts by mass per 100 parts by mass of the vinylidene fluoride polymer, and the antioxidant is contained in an amount of 0.01 to 5 parts by mass per 100 parts by mass of the vinylidene fluoride polymer. (6) The resin composition according to any one of (1) to (5), wherein the resin composition contains 95 parts by mass or more of the vinylidene fluoride polymer per 100 parts by mass of the resin composition. (7) The resin composition according to any one of (1) to (6), wherein the quaternary organic salt contains an alkyl quaternary ammonium sulfate.(8) The resin composition according to any one of (1) to (7), wherein the quaternary organic salt comprises one or more selected from the group consisting of tetraethylammonium bisulfate, tetrapropylammonium bisulfate, and tetrabutylammonium bisulfate. (9) A molded article comprising the resin composition according to any one of (1) to (8).

[0007] According to this disclosure, it is possible to provide a resin composition and molded article containing a vinylidene fluoride polymer that has excellent transparency and can suppress the generation of hydrogen fluoride during molding.

[0008] The resin composition of this disclosure comprises a vinylidene fluoride polymer, a quaternary organic salt, and an antioxidant.

[0009] Here, in this specification, "transparency" means that in a molded article with a thickness of 2 mm formed from the resin composition, the haze value is 40% or less. The haze value is more preferably 30% or less. The haze value (%) can be measured using a haze meter "NDH4000" (manufactured by Nippon Denshoku Industries Co., Ltd.) in accordance with JIS K7136. Furthermore, "suppression of hydrogen fluoride generation" means that the amount of dehydrofluoride generated when heated at 230°C for 2 hours is 100 μg / g or less. The amount of dehydrofluoride generated is more preferably 80 μg / g or less, and even more preferably 50 μg / g or less. The amount of dehydrofluoride generated can be measured as follows: 300 mg of the molded article is placed on a quartz glass boat and heated at 230°C for 2 hours in a 100 mL / min nitrogen flow using a ceramic electric tubular furnace. The generated gas is then converted to NaHCO3. ３ +Na ２ CO ３ After absorption with 20 mL of aqueous solution, the volume was reduced to 30 mL. The NaHCO3 after volume reduction was also measured. ３ and Na ２ CO ３ The initial concentrations of the solutions are adjusted to 1.9 mM and 3.2 mM, respectively. Next, the fluoride ion concentration in this solution is determined using an ion chromatogram.

[0010] (Vinylidene Fluoride Polymer) A vinylidene fluoride polymer is a polymer whose main component is vinylidene fluoride. "Main component is vinylidene fluoride" means that polyvinylidene fluoride contains 50 mol% or more of constituent units derived from vinylidene fluoride. Polyvinylidene fluoride may be a homopolymer of vinylidene fluoride containing substantially 100 mol% of constituent units derived from vinylidene fluoride, or it may be a copolymer of vinylidene fluoride that further contains constituent units derived from other monomers.

[0011] Other monomers copolymerizable with vinylidene fluoride preferably include one or more selected from the group consisting of tetrafluoroethylene, trifluoroethylene, chlorotrifluoroethylene, hexafluoropropylene, vinyl fluoride, 2,3,3,3-tetrafluoropropene, pentafluoropropene, perfluoromethyl vinyl ether, perfluoropropyl vinyl ether, and (meth)acrylic acid esters. Examples of (meth)acrylic acid esters include methyl (meth)acrylate or butyl (meth)acrylate. The content of constituent units derived from other monomers is preferably 10 mol% or less, more preferably 5 mol% or less, and even more preferably 2 mol% or less of the total of all constituent units.

[0012] The vinylidene fluoride polymer can be used alone or in combination of two or more types. For example, it can be a blend containing a vinylidene fluoride homopolymer and one or more vinylidene fluoride copolymers. From the viewpoint of stain resistance, ozone resistance, and solvent resistance, the vinylidene fluoride polymer is preferably a vinylidene fluoride homopolymer. On the other hand, from the viewpoint of flexibility and tear strength, it is preferable to use a vinylidene fluoride copolymer alone or a blend of a vinylidene fluoride copolymer and a vinylidene fluoride homopolymer. From the viewpoint of flexibility, the vinylidene fluoride copolymer is preferably a vinylidene fluoride-hexafluoropropylene copolymer.

[0013] The vinylidene fluoride polymer is preferably present in an amount of 95 parts by mass or more per 100 parts by mass of the resin composition.

[0014] (Heterogeneous linkages) In the vinylidene fluoride polymer according to the present embodiment, there is no particular limitation on the proportion of heterogeneous linkages contained in the vinylidene fluoride polymer, but it is preferably 4.6% or less, more preferably 4.3% or less, still more preferably 4.1% or less, and even more preferably less than 4%. Here, heterogeneous linkages refer to head-to-head linkages and tail-to-tail linkages in a polymer formed by head-to-tail linkages. For example, in a polymer of vinylidene fluoride, usually "CF ２ " and "CH ２ " are alternately bonded, and among these, there are portions where "CF ２ " groups or "CH ２ " groups are bonded to each other. These portions where "CF ２ " groups or "CH ２ " groups are bonded to each other are heterogeneous linkages.

[0015] From the viewpoint of reducing the haze value, the proportion of heterogeneous linkages in the vinylidene fluoride polymer is particularly preferably less than 4% relative to the total number of linkages. The proportion of heterogeneous linkages in the vinylidene fluoride polymer can be adjusted by the polymerization temperature in the production of the polymer. Alternatively, a commercially available polymer having a proportion of heterogeneous linkages falling within the above range may be used.

[0016] The proportion of heterogeneous linkages can be determined from １９ F-NMR measurement of the vinylidene fluoride polymer. More specifically, 40 mg of the vinylidene fluoride polymer is dissolved in 0.8 ml of deuterated dimethylformamide (D7-DMF), and １９ F-NMR measurement is performed at room temperature. The obtained １９The ¹⁹F-NMR spectrum has five main peaks at positions of -91.6 ppm, -92.1 ppm, -94.7 ppm, -113.5 ppm, and -115.9 ppm. Among these peaks, the peaks at -113.5 ppm and -115.9 ppm are identified as peaks derived from heterogeneous bonds. Accordingly, letting S₀ be the sum of the areas of the five peaks, S₁ be the area of the peak at -113.5 ppm, and S₂ be the area of the peak at -115.9 ppm, the heterogeneous bond ratio is calculated by the following formula (F1). Heterogeneous bond ratio (%) = [{(S₁+S₂) / 2} / S₀] × 100 ···Formula (F1)

[0017] (Method for producing vinylidene fluoride polymer) Examples of the method for producing a vinylidene fluoride polymer include emulsion polymerization, soap-free emulsion polymerization, seed emulsion polymerization, suspension polymerization, miniemulsion polymerization, and solution polymerization. Among these, the vinylidene fluoride polymer is preferably produced by suspension polymerization.

[0018] (Quaternary organic salt) The quaternary organic salt comprises a quaternary cation center forming four covalent bonds. The quaternary cation center may be ammonium, phosphonium, or pyridinium. The quaternary cation center forms a covalent bond with an alkyl group or an aryl group. The quaternary organic salt preferably comprises a quaternary ammonium salt or a quaternary phosphonium salt, and more preferably comprises an alkyl or aryl quaternary ammonium salt, or an alkyl or aryl phosphonium salt. Examples of the salt include sulfate, halide, sulfonate, phosphonate, and phosphate. Among these, alkyl quaternary ammonium sulfate is preferably included.

[0019] (Alkyl quaternary ammonium sulfate) The alkyl quaternary ammonium sulfate in the present embodiment is a compound represented by the following formula (2).

[0020] In formula (2), R １ to R ４These are alkyl groups having 1 to 10 carbon atoms, either identical or different from each other. Examples of alkyl groups include ethyl, propyl, isopropyl, butyl, pentyl, and hexyl groups. １ ~R ４ The total number of carbon atoms in the alkyl group is preferably 6 to 30, more preferably 6 to 24, and particularly preferably 8 to 20, from the viewpoint of ensuring sufficient transparency of the molded article.

[0021] In equation (1), R ５ R is an alkyl group, a fluoroalkyl group, or a hydrogen atom. ５ The alkyl group in this context is an alkyl group having 1 to 10 carbon atoms, such as a methyl group and an ethyl group. ５ The fluoroalkyl group in CF ３ , C ２ F ５ These are short-chain fluoroalkyl groups with 1 to 10 carbon atoms. ５ Hydrogen is preferred among them.

[0022] For example, (C ２ H ５ ) ４ N ＋ , (C ３ H ７ ) ４ N ＋ , (C ４ H ９ ) ４ N ＋ , and (C ５ H １１ ) ４ N ＋ Alkyl quaternary ammonium cations such as and CF ３ SO ４ － ,CH ３ SO ４ － HSO ４ － Examples of salts consisting of anions such as these can be given. These compounds can be used individually or in combination of two or more.

[0023] In this embodiment, the alkyl quaternary ammonium sulfate preferably includes alkyl quaternary ammonium hydrogen sulfate. The alkyl quaternary ammonium hydrogen sulfate is preferably one or more selected from the group consisting of tetraethylammonium hydrogen sulfate, tetrapropylammonium hydrogen sulfate, tetrabutylammonium hydrogen sulfate, tetrapentylammonium hydrogen sulfate, and tetrahexylammonium hydrogen sulfate. Of these, the alkyl quaternary ammonium hydrogen sulfate is more preferably tetraethylammonium hydrogen sulfate, tetrapropylammonium hydrogen sulfate, or tetrabutylammonium hydrogen sulfate. The quaternary ammonium hydrogen sulfate preferably includes one or more selected from the group consisting of tetraethylammonium hydrogen sulfate, tetrapropylammonium hydrogen sulfate, and tetrabutylammonium hydrogen sulfate. It is even more preferable that the quaternary ammonium hydrogen sulfate contains at least tetrabutylammonium hydrogen sulfate. These compounds can be used individually or in combination of two or more.

[0024] Other preferred alkyl quaternary ammonium salts besides the alkyl quaternary ammonium sulfates mentioned above include tetrabutylammonium fluoride, tetrabutylammonium chloride, tetrabutylammonium bromide, tetrabutylammonium iodide, tetraethylammonium chloride, hexadecyltrimethylammonium chloride, diethyldioctadecylammonium bromide, tetrabutylammonium p-toluenesulfonate, tetrabutylammonium tetrafluoroborate, hexadecyltrimethylammonium hexafluorophosphate, tetrabutylammonium hexafluorophosphate, tetrabutylammonium hydroxide, tetrabutylammonium phosphate, di-TERT-butylammonium phosphate, tetrabutylammonium nitrate, tetrabutylammonium dichlorobromide, tetrabutylammonium thiocyanate, tetrabutylammonium salicylate, tetrabutylammonium acetate, or tetramethylammonium sulfate.

[0025] Preferred aryl quaternary ammonium salts include benzyltriethylammonium chloride or benzyltriethylammonium hydroxide.

[0026] Preferred alkyl quaternary phosphonium salts include tetrabutylphosphonium chloride, tetrabutylphosphonium bromide, tetrabutylphosphonium tetrafluoroborate, tetrabutylphosphonium hexafluorophosphate, tetrabutylphosphonium acetate, tetrabutylphosphonium tetraphenylborate, or tributyl(ethyl)phosphonium diethyl phosphate.

[0027] Preferred aryl quaternary phosphonium salts include tetraphenylphosphonium chloride, tetraphenylphosphonium bromide, (2-carboxyethyl)triphenylphosphonium bromide, or benzyltriphenylphosphonium chloride.

[0028] To obtain sufficient transparency, the quaternary organic salt is preferably included in an amount of 0.1 parts by mass or more, more preferably 0.5 parts by mass or more, even more preferably 0.8 parts by mass or more, and particularly preferably 1 part by mass or more, per 100 parts by mass of vinylidene fluoride polymer. To obtain sufficient transparency, the quaternary organic salt is preferably included in an amount of 10 parts by mass or less, more preferably 8 parts by mass or less, even more preferably 6 parts by mass or less, and particularly preferably 5 parts by mass or less, per 100 parts by mass of vinylidene fluoride polymer. To obtain sufficient transparency, the quaternary organic salt is preferably included in an amount of 0.1 to 10 parts by mass, 0.5 to 8 parts by mass, 0.8 to 6 parts by mass, or 1 to 5 parts by mass, per 100 parts by mass of vinylidene fluoride polymer.

[0029] (Antioxidant) The antioxidant includes at least one of a phosphite compound represented by formula (1) or a phosphonic acid compound.

[0030] (Phosphite compounds) Phosphite compounds are defined by the following formula (1) [In formula (1), R ａ and R ｂIt is preferable that the compound includes compounds represented by [where each represents an identical or different substituted or unsubstituted alkyl group having 1 to 30 carbon atoms or a substituted or unsubstituted aryl group having 6 to 30 carbon atoms].

[0031] The alkyl group is preferably a linear or branched alkyl group having 1 to 30 carbon atoms. The alkyl group is preferably having 6 to 24 carbon atoms, and more preferably 8 to 18 carbon atoms. Examples of such alkyl groups include 2-ethylhexyl group, nonyl group, decyl group, isodecyl group, octadecyl group, etc., with isodecyl group or octadecyl group being particularly preferred. Examples of substituents include phenyl group, phenol group, tert-butylphenol group, di-tert-butylphenol group, 3,5-t-butyl-4-hydroxyphenyl group, etc., preferably R ａ and R ｂ It is an unsubstituted alkyl group.

[0032] The aryl group is preferably a substituted aryl group, and more preferably a substituted phenyl group. The substituents on the phenyl group are preferably C1-C6 alkyl groups or C6-C10 aryl groups.

[0033] The phosphite compound preferably contains one or more selected from the group consisting of O,O'-dialkyl(C8-C18) pentaerythritol diphosphite, 3,9-bis(2,6-di-tert-butyl-4-methylphenoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane, 3,9-bis(2,4-di-tert-butylphenoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane, and 3,9-bis[2,4-bis(1-methyl-1-phenylethyl)phenoxy]-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane. The phosphite compound more preferably contains O,O'-dialkyl(C8-C18) pentaerythritol diphosphite or 3,9-bis(2,6-di-tert-butyl-4-methylphenoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane. The phosphite compound more preferably contains one or more selected from the group consisting of O,O'-distearyl pentaerythritol diphosphite, bis(isodecyl) pentaerythritol diphosphite, and 3,9-bis(2,6-di-tert-butyl-4-methylphenoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane. The phosphite compound is particularly preferably 3,9-bis(octadecyloxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5,5]undecane.

[0034] A commercially available phosphite antioxidant can be used. For example, a commercially available O,O'-distearylpentaerythritol diphosphite is Adeka Stab PEP-8 (Adeka Corporation). A commercially available 3,9-bis(2,6-di-tert-butyl-4-methylphenoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecan is Adeka Stab PEP-36 (Adeka Corporation). A commercially available bis(isodecyl)pentaerythritol diphosphite is JPE-10 (Johoku Chemical Industry Co., Ltd.).

[0035] The phosphonic acid compound preferably contains one or more selected from the group consisting of phosphonic acid, linear alkylphosphonic acid (1 to 18 carbon atoms), vinylphosphonic acid, allylphosphonic acid, (2-bromoethyl)phosphonic acid, (2-chloroethyl)phosphonic acid, phenylphosphonic acid, (4-hydroxyphenyl)phosphonic acid, (carboxymethyl)phosphonic acid, (2-phenylethyl)phosphonic acid, aminomethylphosphonic acid, and (1-aminoethyl)phosphonic acid. Of these, the phosphonic acid compound preferably contains one or more selected from the group consisting of phosphonic acid, n-octylphosphonic acid, and vinylphosphonic acid.

[0036] The antioxidants mentioned above can be used individually or in combination of two or more.

[0037] The antioxidant is preferably included in an amount of 0.001 parts by mass or more, more preferably 0.005 parts by mass or more, even more preferably 0.008 parts by mass or more, and particularly preferably 0.01 parts by mass or more, per 100 parts by mass of vinylidene fluoride polymer, in order to effectively reduce the haze value and the amount of hydrogen fluoride removed. The antioxidant is preferably included in an amount of 5 parts by mass or less, 3 parts by mass or less, more preferably 2 parts by mass or less, even more preferably 1 part by mass or less, even more preferably 0.8 parts by mass or less, and particularly preferably 0.5 parts by mass or less, per 100 parts by mass of vinylidene fluoride polymer, in order to effectively reduce the haze value and the amount of hydrogen fluoride removed. In order to effectively reduce the haze value and the amount of dehydrofluoride removed, the antioxidant is preferably included in an amount of 0.001 to 5 parts by mass, 0.005 to 3 parts by mass, 0.005 to 2 parts by mass, 0.005 to 1 part by mass, 0.008 to 0.8 parts by mass, or 0.01 to 0.5 parts by mass per 100 parts by mass of vinylidene fluoride polymer.

[0038] (Optional Components) The resin composition according to this embodiment may further contain optional components. Other components include additives and polymers other than those described above. Examples of additives include heat stabilizers, ultraviolet absorbers, light stabilizers, lubricants, plasticizers, bluing agents, or color inhibitors. The resin composition may contain one or more optional components.

[0039] (Method for producing the resin composition) As a method for producing the resin composition according to this embodiment, for example, the resin composition can be obtained by mixing a powder or pellet of vinylidene fluoride polymer with a quaternary organic salt.

[0040] Examples of equipment for mixing materials for resin compositions include Henschel blenders, cylindrical mixers, screw mixers, screw extruders, turbulators, Nauter mixers, V-type mixers, ribbon mixers, dual-arm kneaders, fluidized bed mixers, airflow mixers, rotary disc mixers, roll mixers, rolling mixers, and Reidige mixers.

[0041] A pelletized resin composition can be obtained by drying a mixture of polyvinylidene fluoride and a quaternary organic salt, and then melt-extruding the resulting dried material. Examples of extruders include single-screw extruders, co-direction twin-screw extruders, and anomalous-direction twin-screw extruders.

[0042] The resin composition of this disclosure, by including a vinylidene fluoride polymer, a quaternary organic salt, and an antioxidant, allows molded articles formed from the resin composition to have excellent transparency while suppressing the generation of hydrogen fluoride. Surprisingly, by further including a specific antioxidant, the haze value can be reduced and the amount of dehydrogenated fluoride can be reduced compared to the case in which only the vinylidene fluoride polymer and the quaternary organic salt are included.

[0043] (Molded Article) The molded article of this disclosure comprises the resin composition described above. The molded article can be any shape as long as it is formed from the resin composition described above. For example, the molded article can be an injection-molded article, a pipe, a round bar, a square bar, a sheet, a film, or a fiber. The molded article can be manufactured by any manufacturing method, for example, by injection molding or press molding, calendering, extrusion molding, melt spinning, etc.

[0044] Injection molding is a method of obtaining a molded product by, for example, supplying a resin composition to an injection molding machine, melting it by heating, pouring it into a mold, injecting it, and slowly cooling it.

[0045] Press molding is a method of obtaining a molded product by placing a resin composition in a mold, applying high-temperature press (for example, 230°C for 3 minutes at a pressure of 5 MPa) using a compression molding machine, and then applying cold press (for example, 30°C for 3 minutes). The mold used in press molding can be any material that can be used for heating and pressurizing and that can hold the molten resin composition in the shape to be molded. Examples of such molds include metal molds and metal sheets such as aluminum foil.

[0046] The form of the resin composition is arbitrary as long as it is applicable to the molding method. The resin composition can be, for example, a powder, pellets, flakes, a compressed powder product, or a molded product contained in a mold. In the manufacture of the molded product, the resin composition is heated to a temperature at which it is fully melted and then molded.

[0047] In this embodiment, when the molded body is in the shape of a sheet, it is preferable to pressurize the molten resin composition from the viewpoint of achieving a uniform thickness and a smooth surface of the molded body. That is, in press molding, it is preferable to melt the resin composition by heating the press member and then press it with the press member to form it into a sheet shape. The press member can be any known member capable of achieving the aforementioned heating and pressurizing. The pressure for cold pressing may be the same as or different from that used in high-temperature pressing. The temperature and time for cold pressing can be determined as appropriate. For example, the temperature may be 5°C or higher and 40°C or lower, and the time may be 2 minutes or higher and 10 minutes or lower.

[0048] The method for manufacturing the molded article may further include other steps, to the extent that the effects of this embodiment can be obtained. Examples of such other steps include a preheating step of preheating the mold prior to molding, a molded article manufacturing step of producing a molded article of the resin composition in the mold, a slow cooling step of slowly cooling the molded article after heat and pressure molding, and an annealing step of annealing the obtained molded article.

[0049] In the molded article of this disclosure, the resin composition contains a vinylidene fluoride polymer, a quaternary organic salt, and an antioxidant, thereby suppressing the generation of hydrogen fluoride while maintaining excellent transparency. The molded article of this disclosure has a haze value of 40% or less, more preferably 30% or less, at a thickness of 2 mm, and furthermore, the amount of hydrogen fluoride removed when heated at 230°C for 2 hours is 100 μg / g or less, more preferably 80 μg / g or less, and even more preferably 50 μg / g or less.

[0050] The present invention will be specifically described based on the following examples, but the present invention is not limited to these examples.

[0051] The following materials were used in the examples and comparative examples: TBAHS: Tetrabutylammonium bisulfate TEAHS: Tetraethylammonium bisulfate TPAHS: Tetrapropylammonium bisulfate PEP-8: 3,9-bis(octadecyloxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5,5]undecane (Adeka Stab PEP-8, Adeka Corporation) PEP-36: 3,9-bis(2,6-di-tert-butyl-4-methylphenoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5,5]undecane (Adeka Stab PEP-36, Adeka Corporation) JPE-10: Bis(isodecyl)pentaerythritol diphosphitephosphonic acid: Cas No. 13598-36-2 OPA: n-octylphosphonic acid VPA: vinylphosphonic acid HP-10: 2,2'-methylenebis(4,6-di-tert-butylphenyl)2-ethylhexyl phosphite (Adeka Stab HP-10, Adeka Corporation)

[0052] (Example 1) In a 2-liter autoclave, 1100 g of deionized water was added as a dispersion medium, 0.13 g of Metrose SM-100 (manufactured by Shin-Etsu Chemical Co., Ltd.) as a cellulose-based suspension agent, 3.4 g of 50 wt% diisopropyl peroxydicarbonate-HFE-347pc-f solution as a polymerization initiator, 17.4 g of ethyl acetate as a chain transfer agent, and 430 g of vinylidene fluoride (VDF) were charged. The temperature was raised to 26°C over 40 minutes. Then, while maintaining the temperature at 25°C, the temperature was raised to 40°C over 2 hours when the pressure in the system decreased to 3.5 MPa. The reaction was then continued while maintaining the temperature at 40°C until the pressure in the system decreased to 1.4 MPa. After polymerization was complete, the polymer slurry was heat-treated at 95°C for 60 minutes, then dehydrated, washed with water, and further dried at 80°C for 20 hours to obtain a powder of vinylidene fluoride polymer (PVDF). The physical properties of the obtained vinylidene fluoride polymer were an inherent viscosity of 1.0 dL / g and heterogeneity of 3.8%. This vinylidene fluoride polymer was designated as Polymer 1.

[0053] To 100 parts by mass of the vinylidene fluoride polymer obtained by the above procedure, 2.0 parts by mass of tetrabutylammonium bisulfate (TBAHS) as a quaternary organic salt and 0.1 parts by mass of Adekastab PEP-8 as an antioxidant were added. The vinylidene fluoride polymer used was the one obtained in Example 1. Next, the mixture was extruded using a co-screw extruder (TEM-26, manufactured by Toshiba Machine Co., Ltd.) at a cylinder temperature of 190°C to obtain a pelletized resin composition.

[0054] The obtained pellet-shaped resin composition was sandwiched between aluminum foil and then between stainless steel (SUS) plates, and pressed at 220°C for 5 minutes at a pressure of 10 MPa using a compression molding machine (manufactured by Shinto Metal Industries Co., Ltd., model AYSR-5). Next, the pressed product was immediately cooled (rapidly cooled) by holding it in a cold press at 30°C for 3 minutes while still sandwiched between the SUS plates. This produced a sheet-like molded body. The thickness of the molded body was measured five times per sample using a thickness gauge "DG-925" (manufactured by Ono Sokki Co., Ltd.), and the average value was calculated. This average value was taken as the thickness of the molded body. In Example 1, the thickness of the molded body was 2 mm.

[0055] In Examples 2 to 14 and Comparative Examples 1 to 7, molded bodies were obtained using the same procedure as in Example 1, except that the type of quaternary organic salt, the amount of quaternary organic salt added, the type of antioxidant, or the amount of antioxidant added were changed, as shown in Table 1. The thickness of the molded bodies was 2 mm in all cases.

[0056] The polymer 2 used in Example 14 was obtained by the following method. 10,894 g of deionized water, 2,095 g of methylcellulose, 83.8 g of diethyl carbonate, 4.19 g of diisopropyl peroxydicarbonate, and 4,190 g of vinylidene fluoride were charged into a 20-liter autoclave. The temperature was raised to 50°C over 2 hours and then maintained at 50°C. The maximum pressure reached was 6.5 MPa. After another 0.5 hours, 5,447 g of vinylidene fluoride was gradually added to maintain a polymerization pressure of 5.99 to 6.01 MPa. Polymerization continued at 50°C for approximately 6.3 hours, and suspension polymerization was carried out for a total of 25.2 hours from the start of heating until the pressure dropped to 2.5 MPa. After polymerization was complete, the polymer slurry was dehydrated, washed with water, and then dried at 80°C for 20 hours to obtain polymer powder I. The polymerization rate was 98.5%, and the resulting polymer I had an inherent viscosity of 1.070 dl / g and a heterogeneity of 4.1%. This vinylidene fluoride polymer was designated as polymer 2.

[0057] The haze value and dehydrofluoride content of the molded product were measured using the following method.

[0058] [Haze Value] The haze of the molded product was measured using a haze meter "NDH4000" (manufactured by Nippon Denshoku Industries Co., Ltd.) in accordance with JIS K7136.

[0059] [Hydrogen fluoride removal amount] 300 mg of a sheet-shaped molded body was placed on a quartz glass boat and heated at 230°C for 2 hours in a 100 mL / min nitrogen flow using a ceramic electric tubular furnace (manufactured by Asahi Rika Seisakusho Co., Ltd.). The generated gas was collected as NaHCO3. ３ +Na ２ CO ３ After absorption with 20 mL of aqueous solution, the volume was reduced to 30 mL. The NaHCO3 after volume reduction was also measured. ３ and Na ２ CO ３The initial concentrations were adjusted to 1.9 mM and 3.2 mM, respectively. The fluoride ion concentration was determined using an ion chromatogram (Tosoh Corporation, model IC-2010).

[0060]

[0061] Comparing Comparative Example 1 with Comparative Example 2, it was found that while the haze value improved with the quaternary organic salt, the thermal stability of the resin deteriorated, and the amount of hydrogen fluoride removed increased significantly. Comparing Comparative Example 1 with Comparative Examples 3-6, it was found that the haze value did not improve with the antioxidant, and the amount of hydrogen fluoride removed was the same or increased. Comparative Example 7 contains a phosphite-based antioxidant that does not fall under formula (1), and when such an antioxidant is included, the haze value deteriorates, the thermal stability of the resin deteriorates, and the amount of hydrogen fluoride removed also increases.

[0062] In contrast, in Examples 1 to 14, by including a quaternary organic salt and a specific antioxidant, the haze value was reduced to 40 or less, the thermal stability of the resin was improved, and the amount of hydrogen fluoride removed was also reduced.

Claims

1. A compound comprising a vinylidene fluoride polymer, a quaternary organic salt, and an antioxidant, wherein the antioxidant is a phosphonic acid compound or the following formula (1) [In formula (1), R ａ and R ｂ A resin composition comprising at least one of phosphite compounds represented by [where is a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms or a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, which are the same or different from each other].

2. The resin composition according to claim 1, wherein the quaternary organic salt comprises a quaternary ammonium salt or a quaternary phosphonium salt.

3. The resin composition according to claim 1, wherein the phosphite compound comprises one or more selected from the group consisting of O,O'-dialkyl(C8-C18) pentaerythritol diphosphite, 3,9-bis(2,6-di-tert-butyl-4-methylphenoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane, 3,9-bis(2,4-di-tert-butylphenoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane, and 3,9-bis[2,4-bis(1-methyl-1-phenylethyl)phenoxy]-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane.

4. The resin composition according to claim 1, wherein the phosphonic acid compound comprises one or more selected from the group consisting of phosphonic acid, linear alkylphosphonic acid (having 1 to 18 carbon atoms), vinylphosphonic acid, allylphosphonic acid, (2-bromoethyl)phosphonic acid, (2-chloroethyl)phosphonic acid, phenylphosphonic acid, (4-hydroxyphenyl)phosphonic acid, (carboxymethyl)phosphonic acid, (2-phenylethyl)phosphonic acid, aminomethylphosphonic acid, and (1-aminoethyl)phosphonic acid.

5. The resin composition according to claim 1, wherein the quaternary organic salt is contained in an amount of 0.1 to 5 parts by mass per 100 parts by mass of the vinylidene fluoride polymer, and the antioxidant is contained in an amount of 0.01 to 5 parts by mass per 100 parts by mass of the vinylidene fluoride polymer.

6. The resin composition according to claim 1, wherein the resin composition contains 95 parts by mass or more of the vinylidene fluoride polymer per 100 parts by mass of the resin composition.

7. The resin composition according to claim 1, wherein the quaternary organic salt comprises an alkylquaternary ammonium sulfate.

8. The resin composition according to claim 1, wherein the quaternary organic salt comprises one or more selected from the group consisting of tetraethylammonium bisulfate, tetrapropylammonium bisulfate, and tetrabutylammonium bisulfate.

9. A molded article comprising the resin composition according to any one of claims 1 to 8.

Images