JP6517068B2 - Vinylidene fluoride-based resin composition and molded product, and method for producing them - Google Patents

Description

  The present invention relates to a vinylidene fluoride resin composition and a molded product, and a method for producing them.

Vinylidene fluoride polymers are crystalline polymers and are used in various moldings as polymers with good mechanical strength. One of the applications of vinylidene fluoride polymers is the material of mining pipes for submarine oil fields. Physical properties required in this application include, for example, flexibility (low elastic modulus), chemical resistance, heat resistance, low-temperature impact strength and the like, and techniques for improving such physical properties have been developed. . Patent Document 1 discloses a polymer composition based on polyvinylidene fluoride (PVDF) homopolymer and fluorocopolymer, which can be used as a material for mining pipes of a submarine oil field, wherein a predetermined amount of PVDF homopolymer, A polymer composition is described which comprises a thermoplastic copolymer of vinylidene fluoride (VF ₂ ) and another fluoromonomer, and a predetermined amount of a low or high molecular weight plasticizer. The polymer composition is described to have improved mechanical properties at low temperatures.

  Although the impact strength at low temperatures is particularly important in this application, the impact strength of the molded product largely depends on the molecular weight of the vinylidene fluoride polymer, and the higher the molecular weight, the higher the impact strength. However, when the molecular weight increases, the viscosity at the time of melting increases, and the load current applied to the molding machine increases, so that the processability is significantly reduced. On the other hand, if the processing temperature is raised to lower the viscosity, coloring will occur. Therefore, it is common to add high density polyethylene (HDPE), which has the effect of lowering the viscosity at the time of melting, as an inner lubricant to the molded articles of high viscosity vinylidene fluoride polymers in order to improve the coloration. . On the other hand, since a vinylidene fluoride polymer forms a spherulite structure, if spherulites grow largely during molding, the impact strength of the molded body is lowered. For this reason, there is a demand for a vinylidene fluoride resin which is difficult to increase spherulite size in melt molding and is excellent in impact resistance at low temperatures.

Japanese Patent Application Laid-Open No. 6-287390 (released on October 11, 1994)

  The present invention has been made in view of the above problems, and an object thereof is a vinylidene fluoride resin molded article having high impact strength at low temperature and a vinylidene fluoride resin composition which can be suitably used for the production of the molded article. It is in providing things.

  As a result of intensive studies by the present inventors to solve the above problems, it has been found that addition of a predetermined amount of a certain type of crystal nucleating agent to a vinylidene fluoride polymer improves the impact strength at low temperatures. The present invention has been completed.

  That is, the vinylidene fluoride-based resin composition according to the present invention comprises a vinylidene fluoride-based polymer and a crystal nucleating agent which is an acryl-modified polytetrafluoroethylene, and the crystal nucleating agent contains the vinylidene fluoride-based heavy oil. It is characterized in that 0.05 to 5 parts by weight is contained with respect to 100 parts by weight of the combination.

  In the vinylidene fluoride resin composition according to the present invention, the crystal nucleating agent is preferably contained in an amount of 0.1 to 3 parts by weight with respect to 100 parts by weight of the vinylidene fluoride polymer.

  In the vinylidene fluoride resin composition according to the present invention, the vinylidene fluoride polymer is a homopolymer of vinylidene fluoride, a copolymer of vinylidene fluoride and hexafluoropropylene, or a mixture thereof. Is preferred.

  In the vinylidene fluoride resin composition according to the present invention, the copolymer of vinylidene fluoride and hexafluoropropylene preferably contains 75% by weight or more of a unit derived from a vinylidene fluoride monomer.

  In the vinylidene fluoride resin composition according to the present invention, the molar ratio of vinylidene fluoride / hexafluoropropylene is preferably 98/2 to 80/20.

  In the vinylidene fluoride-based resin composition according to the present invention, the vinylidene fluoride-based polymer is preferably obtained by suspension polymerization.

  In the vinylidene fluoride-based resin composition according to the present invention, the vinylidene fluoride-based polymer preferably has a solution viscosity of 1.0 to 2.1 dl / g.

  In the method for producing a vinylidene fluoride resin composition according to the present invention, 100 parts by weight of a vinylidene fluoride polymer and 0.05 to 5 parts by weight of a crystal nucleating agent which is an acrylic-modified polytetrafluoroethylene are mixed. It is characterized by including a process.

  The method for producing a vinylidene fluoride-based resin molded product according to the present invention is characterized by including the step of melt-molding the above vinylidene fluoride-based resin composition.

  The vinylidene fluoride-based resin molded article according to the present invention is characterized by being produced by the method for producing a vinylidene fluoride-based resin molded article.

  The vinylidene fluoride-based resin molded product according to the present invention may be a component of a flexible pipe for submarine oil field mining.

  INDUSTRIAL APPLICABILITY The present invention can provide a vinylidene fluoride resin molded article having high impact strength at low temperature, and a vinylidene fluoride resin composition that can be suitably used for the production of the molded article.

It is a figure which shows the result of an Izod impact test in the Example of this invention. It is a figure which shows the result of a tension test in the Example of this invention. It is a figure which shows the result of effect confirmation of the crystal nucleating agent in the Example of this invention.

[Vinylidene fluoride resin composition]
The vinylidene fluoride resin composition according to the present invention comprises a vinylidene fluoride polymer and a crystal nucleating agent which is an acryl-modified polytetrafluoroethylene, and the crystal nucleating agent is 100 weight parts of the vinylidene fluoride polymer. It is contained 0.05 to 5 parts by weight with respect to parts.

  When molded, the vinylidene fluoride resin composition according to the present invention has high low-temperature impact strength as compared with the case where it does not contain a crystal nucleating agent. In the present invention, "low temperature impact strength" refers to impact strength at low temperatures. Here, "low temperature" refers to 20 ° C or less, preferably -20 ° C to 20 ° C, more preferably -10 ° C to 10 ° C. Further, “impact strength” refers to, for example, Izod impact strength, Charpy impact strength, or drop impact strength, and in particular refers to Izod impact strength.

(Vinylidene fluoride polymer)
In the present invention, the "vinylidene fluoride polymer" refers to a homopolymer of vinylidene fluoride monomer, and a copolymer of a monomer copolymerizable with vinylidene fluoride and a vinylidene fluoride monomer. The vinylidene fluoride-based polymer contained in the vinylidene fluoride-based resin composition according to the present invention comprises a homopolymer of vinylidene fluoride monomer and a copolymer of a monomer copolymerizable with vinylidene fluoride and a vinylidene fluoride monomer It may be any of the above. Further, the vinylidene fluoride-based resin composition according to the present invention may contain two or more kinds of vinylidene fluoride-based polymers having different compositions and / or average molecular weights. The vinylidene fluoride-based polymer preferably contains 50% by weight or more of a unit derived from a vinylidene fluoride monomer, and more preferably 85% by weight or more.

  Monomers copolymerizable with vinylidene fluoride include, but are not necessarily limited to, vinyl fluoride, trifluoroethylene, tetrafluoroethylene, chlorotrifluoroethylene, hexafluoropropylene and perfluoroalkyl vinyl ether etc. is not. In addition, as monomers not containing fluorine, ethylene, monomethyl maleate and allyl glycidyl ether can also be used, but are not necessarily limited thereto. As the monomer copolymerizable with vinylidene fluoride, hexafluoropropylene, chlorotrifluoroethylene, trifluoroethylene and perfluoroalkylvinylether are preferable from the viewpoint of elastic modulus and chemical resistance, and hexafluoropropylene is more preferable.

  In the copolymer of vinylidene fluoride and hexafluoropropylene, from the viewpoint of elastic modulus and chemical resistance, the unit derived from vinylidene fluoride monomer is preferably 60% by weight or more and 95% by weight or less, and 75% by weight The content is more preferably 95% by weight or less, still more preferably 85% by weight or more and 95% by weight or less.

  From the viewpoint of impact strength and processability, the vinylidene fluoride polymer preferably has a solution viscosity (inherent viscosity) of 0.72 to 2.5 dl / g, and is 1.0 to 2.1 dl / g. Is more preferable, and 1.3 to 1.7 dl / g is more preferable. The solution viscosity is the logarithmic viscosity at 30 ° C. of a solution of 4 g of a vinylidene fluoride polymer dissolved in 1 liter of N, N-dimethylformamide.

  The average molecular weight of the vinylidene fluoride polymer is not particularly limited, but can be, for example, 200,000 to 700,000 as a weight average molecular weight. The weight average molecular weight can be measured by gel permeation chromatography (GPC). In measurement, for example, polystyrene as a standard polymer and NMP as an eluent may be used.

  The vinylidene fluoride polymer is preferably a homopolymer of vinylidene fluoride, a copolymer of vinylidene fluoride and hexafluoropropylene, or a mixture thereof from the viewpoint of productivity and processability.

  The vinylidene fluoride polymer is a vinylidene fluoride monomer alone as described above, or a monomer copolymerizable with the vinylidene fluoride monomer as described above and a vinylidene fluoride monomer (hereinafter referred to collectively as “fluorine Obtained by polymerizing a vinylidene fluoride-based monomer).

  Examples of the method for polymerizing a vinylidene fluoride monomer include suspension polymerization, emulsion polymerization, dispersion polymerization, bulk polymerization and solution polymerization, and the like, with suspension polymerization being preferred. In the suspension polymerization method, the crystallinity of the resulting vinylidene fluoride polymer is high, and since no emulsifier and coagulant are used, impurities can be easily reduced. In addition, the suspension polymerization method has a simple reaction system and reaction mechanism, has high versatility of usable monomers, and has few limitations. Furthermore, suspension polymerization is easy to control molecular weight.

  The polymerization of the vinylidene fluoride monomer may be carried out in the presence of a polymerization initiator, a suspending agent, a chain transfer agent and the like.

  The specific method of polymerizing the vinylidene fluoride monomer may be, for example, according to a conventionally known method. Alternatively, commercially available vinylidene fluoride polymers may be used.

(Crystal nucleating agent)
The crystal nucleating agent contained in the vinylidene fluoride resin composition according to the present invention is acryl-modified polytetrafluoroethylene.

  The acrylic-modified polytetrafluoroethylene is, for example, polytetrafluoroethylene to which an acrylic such as methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate or the like is added or mixed. The molecular weight of the acryl-modified polytetrafluoroethylene is not particularly limited, and is, for example, 1,000,000 or more. The acrylic-modified polytetrafluoroethylene may be powder, dispersion, pellets, flakes or the like. Alternatively, the acrylic modified polytetrafluoroethylene may be in the form of a masterbatch. In the case of powder, the particle size can be, for example, 1 μm to 5000 μm.

  As acrylic modified polytetrafluoroethylene, for example, "Metabrene A-3000", "Metabrene A-3800", "Metabrene A-3750" and "Metabrene A-3700" (trade name, manufactured by Mitsubishi Rayon Co., Ltd.) Etc.

  The crystal nucleating agent contained in the vinylidene fluoride resin composition may be one type or a plurality of types.

  In the vinylidene fluoride resin composition according to the present invention, the crystal nucleating agent is contained in an amount of 0.05 to 5 parts by weight with respect to 100 parts by weight of the vinylidene fluoride polymer. From the viewpoint of achieving higher low-temperature impact strength, the crystal nucleating agent is preferably contained in an amount of 0.1 to 3 parts by weight, with respect to 100 parts by weight of the vinylidene fluoride polymer, 0.3 to 3 parts by weight It is more preferable that a part is included. In addition, when 2 or more types of crystal nucleating agents are contained, total content is contained in the said range. When two or more vinylidene fluoride polymers are contained, the total content is 100 parts by weight.

(Other ingredients)
The vinylidene fluoride-based resin composition according to the present invention may contain components other than the above-mentioned vinylidene fluoride-based polymer and the crystal nucleating agent as long as the essential characteristics in the present invention are not impaired. Examples of such components include antioxidants, lubricants, stabilizers, coloring inhibitors, plasticizers, dispersants and antistatic agents.

  Examples of the antioxidant include IRGANOX (registered trademark) 1076, IRGANOX 1010, and the like.

  As the lubricant, for example, high density polyethylene, wax, glycerin and the like can be mentioned.

  As the stabilizer and the anti-coloring agent, for example, calcium carbonate, magnesium hydroxide, zinc oxide and the like can be mentioned.

  The addition amount of the above components can be, for example, 0.01 to 3.0 parts by weight with respect to 100 parts by weight of the vinylidene fluoride polymer.

[Method for producing vinylidene fluoride resin composition]
In the method for producing a vinylidene fluoride resin composition according to the present invention, 100 parts by weight of a vinylidene fluoride polymer and 0.05 to 5 parts by weight of a crystal nucleating agent which is an acrylic-modified polytetrafluoroethylene are mixed. Including the steps. According to the production method of the present invention, the above-mentioned vinylidene fluoride polymer can be suitably obtained.

  The description of the vinylidene fluoride polymer and the crystal nucleating agent is the same as that of the above [vinylidene fluoride resin composition].

  The mixing of the vinylidene fluoride polymer and the crystal nucleating agent may be by powder mixing in the dry state, or the slurry obtained by the polymerization, or the vinylidene fluoride polymer in the latex state or in the wet state after dehydration. After adding the nucleating agent to obtain a mixture, it may be dried. At this time, the crystal nucleating agent may be added in the form of powder, solution or dispersion, and an organic solvent such as ethanol or ethyl acetate, a surfactant, etc., to aid the mixing to the vinylidene fluoride polymer. Alternatively, dispersion aids and the like may be added. Moreover, you may add in the form of a masterbatch.

  A crystal nucleating agent was mixed with a vinylidene fluoride polymer by a mixer or the like, and after melt-kneading with a twin-screw extruder etc., it was granulated in the form of pellets or flakes to stabilize the composition. You may obtain the vinylidene fluoride type-resin composition of a state. Thus, the composition and physical properties of the obtained product can be stabilized by performing melt molding using the vinylidene fluoride resin composition in a state in which the composition is stabilized.

  The ratio of mixing the crystal nucleating agent is 0.05 to 5 parts by weight with respect to 100 parts by weight of the vinylidene fluoride polymer. From the viewpoint of achieving higher low-temperature impact strength, the mixing ratio of the crystal nucleating agent is preferably 0.1 to 3 parts by weight with respect to 100 parts by weight of the vinylidene fluoride polymer, and 0.3 to More preferably, it is 3 parts by weight.

  The components other than the vinylidene fluoride polymer and the crystal nucleating agent may be mixed simultaneously when mixing the vinylidene fluoride polymer and the crystal nucleating agent, or may be mixed successively.

  Examples of the mixing apparatus include a Henschel blender, a cylindrical mixer, a screw mixer, a screw extruder, a turbulizer, a Nauta mixer, a V mixer, a ribbon mixer, a twin arm kneader, A fluid type mixer, an air flow type mixer, a rotary disk type mixer, a roll mixer, a rolling type mixer, a Lodige mixer, etc. are mentioned.

  Examples of the extruder include a single-screw extruder, a co-rotating twin-screw extruder, and a co-rotating twin-screw extruder.

  Examples of the method for pelletizing include strand cut, mist cut, hot cut and underwater cut.

[Vinylidene fluoride-based resin molded product and method for producing the same]
The method for producing a vinylidene fluoride-based resin molded product according to the present invention includes the step of melt-molding the above-mentioned vinylidene fluoride-based resin composition.

  As a method of melt molding, although a method using an injection molding machine, an extrusion molding machine, a blow molding machine, a compression molding machine and the like can be mentioned, it may be appropriately selected depending on the purpose of use of the molded product to be produced. A specific method of melt molding may be, for example, according to a conventionally known method.

  The vinylidene fluoride-based resin molded article produced by the production method according to the present invention has improved low-temperature impact strength as compared with the case where it does not contain a crystal nucleating agent, as shown in the following examples. Therefore, the vinylidene fluoride-based resin molded article according to the present invention can be suitably used, for example, in articles used at low temperatures. In one embodiment, the vinylidene fluoride-based resin molded product according to the present invention is a component of a flexible pipe for submarine oil field mining.

  Examples will be shown below, and the embodiment of the present invention will be described in more detail. Of course, the present invention is not limited to the following examples, and it is needless to say that various aspects are possible as to details. Furthermore, the present invention is not limited to the embodiments described above, and various modifications can be made within the scope of the claims, and embodiments obtained by appropriately combining the disclosed technical means are also included. It is included in the technical scope of the invention. Also, all of the documents described in the present specification are incorporated by reference.

[Production of vinylidene fluoride resin composition]
A predetermined amount of a crystal nucleating agent (see Table 1), a lubricant (HF 560 (manufactured by Japan Polyethylene Corporation) (ground product)) 0.5 parts by weight, a stabilizer (IRGANOX 1076) per 100 parts by weight of a vinylidene fluoride polymer 0.12 parts by weight (manufactured by BASF) and 0.03 parts by weight of a stabilizer (Brilliant-1500 (manufactured by Shiraishi Calcium Co., Ltd.)) are added, and a twin screw extruder with the same direction (manufactured by Toshiba Machine Co., Ltd.) According to TEM-26), pelletized vinylidene fluoride is extruded at a predetermined temperature (° C.) (C1 / C2 / C3 / C4 / C5 / C6 / DH = 190/190/190/190/190/190/190) A resin based composition was obtained.

  The vinylidene fluoride polymer A is a homopolymer of vinylidene fluoride and has a solution viscosity η of 1.7 (dl / g). The vinylidene fluoride polymer B is a copolymer of vinylidene fluoride / hexafluoropropylene = 98/2, and η = 1.7 (dl / g). The vinylidene fluoride polymer C is a copolymer of vinylidene fluoride / hexafluoropropylene = 88/12, and η = 1.1 (dl / g).

  In addition, Metabrene A-300 (manufactured by Mitsubishi Rayon Co., Ltd.) is a powder of acrylic-modified polytetrafluoroethylene. NEUSTER NU-100 (manufactured by Shin Nippon Rika Co., Ltd.) is a powder of N, N'-dicyclohexyl-2,6-naphthalenedicarboxamide. KTL-500F (manufactured by Kitamura Co., Ltd.) is a powder of polytetrafluoroethylene. Boronite SP-2 (manufactured by Denki Kagaku Kogyo Co., Ltd.) is a powder of boron nitride.

[Production of vinylidene fluoride-based resin molded product]
The vinylidene fluoride-based resin composition obtained above was subjected to temperature (° C.): C1 / C2 / C3 / C4 / AD / D = 200/220 using an extruder (manufactured by PLA Giken Co., Ltd., PEX 40-24). / 230/230/230/230, taking-up speed: 0.6 mm / min rectangular molding was carried out to obtain a vinylidene fluoride resin molded article having a width of 30 mm and a thickness of 3.2 mm.

[Izod impact test]
The vinylidene fluoride resin molded product obtained above was cut into a width of 12.7 mm, a length of 60 mm, and a width of 12.7, and a V notch of 45 ° and 2.7 mm was inserted. The atmosphere of the measurement environment was -10 ° C, 0 ° C, and 10 ° C. Tests were conducted in accordance with JIS K7110 using an Izod measuring machine manufactured by Toyo Seiki Co., Ltd.

  The composition of the vinylidene fluoride resin composition and the Izod impact strength of the vinylidene fluoride resin molded product are shown in Table 1.

[Production of vinylidene fluoride resin composition-2]
0.3 part by weight of nucleating agent, 100 parts by weight of vinylidene fluoride polymer D (a homopolymer of vinylidene fluoride, solution viscosity η = 1.0 (dl / g)), lubricant (HF 560) 0.5 parts by weight, 0.12 parts by weight of stabilizer (IRGANOX 1076), and 0.03 parts by weight of stabilizer (Brilliant-1500) are added, and a pelletized vinylidene fluoride resin composition is prepared in the same manner as described above. I got

[Production of vinylidene fluoride-based resin molded product-2]
The vinylidene fluoride-based resin composition obtained above was rectangular-molded by the same method as described above to obtain a vinylidene fluoride-based resin molded product with a width of 30 mm and a thickness of 3.2 mm.

[Izod impact test-2]
The Izod impact test was conducted on the vinylidene fluoride resin molded product obtained above in the same manner as described above.

  The results of Izod impact test of the vinylidene fluoride resin molded product are shown in FIG. As shown in FIG. 1, when methabrene A-3000 was added, Izod impact strength was improved at each temperature.

[Tension test]
Punched samples were prepared according to a dumbbell cutter (ASTM D638-4). The tensile test was performed using autograph AG-2000 about the produced sample. In addition, the fractured surface after sample breakage was observed using a digital microscope (manufactured by Keyence, VHX).

  The results are shown in FIG. (A) of FIG. 2 is a figure which shows the result of a tension test. (B) of FIG. 2 is a microscope image of the fractured surface after fracture. As shown in (a) of FIG. 2, the crystal nucleating agents other than metabrene A-3000 significantly reduced the breaking elongation as compared to the case without the crystal nucleating agent, but in the case of methabrene A-3000 There was no significant decrease in elongation. Moreover, as shown in (b) of FIG. 2, metabrene A-3000 did not have a large crack.

[Confirmation of effect of crystal nucleating agent (reference)]
The sample was produced by a hot press molding machine. Spherulites of the prepared sample were observed using a polarization microscope (Olympus BH-2). The spherulite radius was also determined on a microscope standard scale. The crystallization temperature of the prepared sample was determined from the calorific value at the time of temperature decrease of DSC.

  The results are shown in FIG. (A) of FIG. 3 is a polarization microscope image. (B) of FIG. 3 is a figure which shows spherulite radius and crystallization temperature. As shown in FIG. 3, it was confirmed that all the nucleating agents used had the effect of reducing spherulites.

  The present invention can be used for producing a vinylidene fluoride resin composition and a vinylidene fluoride resin molding.

Claims (8)

A vinylidene fluoride polymer and a crystal nucleating agent which is an acryl-modified polytetrafluoroethylene,
A vinylidene fluoride-based resin composition, wherein the crystal nucleating agent is contained in an amount of 0.1 to 3 parts by weight with respect to 100 parts by weight of the vinylidene fluoride-based polymer. Said vinylidene fluoride polymer is characterized by copolymer of homopolymer or vinylidene fluoride and hexafluoropropylene vinylidene fluoride, or a mixture thereof, fluoride according to claim 1 Vinylidene-based resin composition. The vinylidene fluoride resin composition according to claim 2 , wherein the copolymer of vinylidene fluoride and hexafluoropropylene contains 75% by weight or more of a unit derived from a vinylidene fluoride monomer. The fluorine according to claim 2 or 3 , wherein the vinylidene fluoride / hexafluoropropylene copolymer has a vinylidene fluoride / hexafluoropropylene molar ratio of 98/2 to 80/20. Vinylidene-based resin composition. The vinylidene fluoride-based resin composition according to any one of claims 1 to 4 , wherein the vinylidene fluoride-based polymer has a solution viscosity of 1.0 to 2.1 dl / g. A vinylidene fluoride-based resin composition comprising the step of mixing 100 parts by weight of a vinylidene fluoride-based polymer and 0.1 to 3 parts by weight of a crystal nucleating agent which is an acryl-modified polytetrafluoroethylene. Manufacturing method. A process for producing a vinylidene fluoride-based resin molded article, comprising the step of melt-molding the vinylidene fluoride-based resin composition according to any one of claims 1 to 5 . Any one offshore oil drilling for flexible pipe parts article comprising vinylidene fluoride resin composition according to the claims 1-5.