Fluororesin joint member and manufacturing method thereof

Abstract

To provide a fluororesin joint member with improved joint strength, and a method for manufacturing the same.SOLUTION: There is provided a fluororesin joint member in which at least two fluororesin members are bonded by vibration welding, wherein the fluororesin member contains a melt-moldable fluororesin, the melt-moldable fluororesin comprises at least one kind selected from the group consisting of a copolymer having a TFE unit and a copolymer having a CTFE unit, a melting point of the melt-moldable fluororesin is 290°C or less, a glass transition temperature of the melt-moldable fluororesin is 100°C or less, and a flexural modulus of the melt-moldable fluororesin is 700 MPa or more.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a fluororesin bonding member and a method for manufacturing the same. [Background technology]

[0002] Fluorine resins are excellent in heat resistance, flame retardancy, chemical resistance, weather resistance, non-stickiness, low friction, low dielectric properties, etc., and are therefore used in a wide range of applications (such as corrosion-resistant piping materials for chemical plants, materials for agricultural greenhouses, release coating materials for kitchen utensils, and coating materials for electric wires). In particular, melt-moldable fluororesins are amenable to various molding techniques, and therefore have a wide range of applications. For example, Patent Document 1 proposes joining fluororesin members containing fluororesin together by vibration welding. After bringing the joining surfaces of the fluororesin members into contact with each other, they can be welded and joined by the frictional heat generated by vibrating them in the direction of the contact surfaces. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-218697 Summary of the Invention [Problem to be solved by the invention]

[0004] However, according to the investigations of the present inventors, the manufacturing method of Patent Document 1 sometimes does not provide sufficient strength at the joint between the fluororesin members.

[0005] The present invention provides a fluororesin joint member having improved joint strength and a method for producing the same. [Means for solving the problem]

[0006] The present invention has the following aspects. [1] A fluororesin bonded member in which at least two or more fluororesin members are bonded by vibration welding, the fluororesin member contains a melt-moldable fluororesin, the melt-moldable fluororesin comprises at least one selected from the group consisting of a copolymer having a unit based on tetrafluoroethylene and a copolymer having a unit based on chlorotrifluoroethylene, The melting point of the melt-moldable fluororesin is 290°C or less, The melt-moldable fluororesin has a glass transition temperature of 100°C or less, A fluororesin joining member, wherein the melt-moldable fluororesin has a flexural modulus of 700 MPa or more. [2] The fluororesin joining member according to [1], wherein the melt-moldable fluororesin has a Rockwell hardness of 30 or more on the R scale. [3] The fluororesin joining member according to [1] or [2], wherein the melt-moldable fluororesin has a dynamic friction coefficient of 0.2 or more. [4] The fluororesin bonding member according to any one of [1] to [3], wherein the melt-moldable fluororesin has a thermal conductivity of 0.15 W / m·K or more. [5] The fluororesin bonding member according to any one of [1] to [4], wherein the melt viscosity of the melt-formable fluororesin is 1000 Pa s or more, measured at a temperature 40°C higher than the melting point of the melt-formable fluororesin and at a shear rate of 12 / s. [6] The fluororesin bonding member according to any one of [1] to [5], wherein the melt viscosity of the melt-formable fluororesin is 2000 Pa s or less, measured under conditions where the temperature is 40°C higher than the melting point of the melt-formable fluororesin and the shear rate is 1200 / s. [7] The fluororesin bonding member according to any one of [1] to [6], wherein the melt-moldable fluororesin contains a copolymer having units based on tetrafluoroethylene and units based on ethylene.

[0007] [8] A method for manufacturing a fluororesin bonded member, in which at least two or more fluororesin members are bonded by vibration welding, comprising: the fluororesin member contains a melt-moldable fluororesin, The melting point of the melt-moldable fluororesin is 290°C or less, The melt-moldable fluororesin has a glass transition temperature of 100°C or less, The melt-moldable fluororesin has a flexural modulus of 700 MPa or more, The manufacturing method, wherein the holding pressure when joining the fluororesin members by vibration welding is 5 to 30 MPa, and the holding time when joining the fluororesin members by vibration welding is 3 to 20 seconds. [9] The method according to [8], wherein the melt-moldable fluororesin has a Rockwell hardness of 30 or more on the R scale.

[10] The manufacturing method according to [8] or [9], wherein the surface roughness of the joining surface of the fluororesin member is 0.01 μm or more.

[11] The method according to any one of [8] to

[10] , wherein the melt-moldable fluororesin has a dynamic friction coefficient of 0.2 or more.

[12] The method according to any one of [8] to

[11] , wherein the melt-moldable fluororesin has a thermal conductivity of 0.15 W / m·K or more.

[13] The production method according to any one of [8] to

[12] , wherein the melt viscosity of the melt-formable fluororesin is 1000 Pa s or more, measured under conditions where the temperature is 40°C higher than the melting point of the melt-formable fluororesin and the shear rate is 12 / s.

[14] The production method according to any one of [8] to

[13] , wherein the melt viscosity of the melt-formable fluororesin is 2000 Pa s or less, measured under conditions where the temperature is 40°C higher than the melting point of the melt-formable fluororesin and the shear rate is 1200 / s.

[15] The method according to any one of [8] to

[14] , wherein the melt-moldable fluororesin comprises at least one selected from the group consisting of copolymers having units based on tetrafluoroethylene and copolymers having units based on chlorotrifluoroethylene.

[16] The method according to

[15] , wherein the melt-moldable fluororesin contains a copolymer having units based on tetrafluoroethylene and units based on ethylene. [Effects of the Invention]

[0008] According to the present invention, a fluororesin bonding member having improved bond strength and a method for manufacturing the same are provided. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 shows an example of a fluororesin joining member. DETAILED DESCRIPTION OF THE INVENTION

[0010] The meanings of the terms are as follows: "Monomer" means a compound having a polymerizable carbon-carbon double bond. The term "monomer-based unit" refers collectively to an atomic group formed directly by polymerizing one monomer molecule and an atomic group obtained by chemically converting a part of the atomic group. A monomer-based unit is also simply referred to as a "monomer unit." A compound represented by formula (n) is referred to as "compound (n)," where n is a natural number. "Melt-formable" means exhibiting melt flowability. "Exhibiting melt fluidity" means that there exists a temperature at which the melt flow rate is 0.1 to 1000 g / 10 min under a load of 49 N at a temperature at least 20° C. higher than the melting point of the resin. "Melt flow rate" is the melt mass flow rate (MFR) defined in JIS K 7210:1999 (ISO 1133:1997). The term "etheric oxygen atom" refers to an oxygen atom that forms an ether bond (-O-) between carbon atoms.

[0011] The "melting point" is the temperature corresponding to the maximum value of the melting peak measured by differential scanning calorimetry (DSC). The "glass transition temperature" is the temperature corresponding to the maximum value of the tan δ peak measured by dynamic mechanical analysis (DMA). The "Rockwell hardness" is determined by the method described in the examples. The "flexural modulus" is determined by the method described in the examples. The "dynamic friction coefficient" is determined by the method described in the examples. The "thermal conductivity" is determined by the method described in the examples. The "melt viscosity" is determined by the method described in the examples. The "surface roughness" is determined by the method described in the examples. The "tensile strength at the bonded surface" is determined by the method described in the examples. The symbol "to" indicating a range of values ​​means that the values ​​before and after the symbol "to" are included as the lower and upper limits. The lower and upper limits of the ranges disclosed in this specification can be combined in any way to create new ranges of values.

[0012] Hereinafter, several embodiments will be described with reference to the drawings as appropriate. The following description relates to representative examples of embodiments of the invention, and the present invention is not limited to the following description. Furthermore, the dimensional ratios in each drawing may differ from the actual ones for the sake of convenience of explanation.

[0013] [Fluororesin bonding materials] The fluororesin bonding member of the present invention is formed by bonding at least two fluororesin members together by vibration welding. As shown in Fig. 1, the fluororesin bonding member 5 is formed by bonding a fluororesin member 1 and a fluororesin member 2 together by vibration welding.

[0014] The shape of the fluororesin member is not particularly limited. Although the example shown in Fig. 1 has a rectangular parallelepiped shape, it may also be cylindrical, have a hollow portion, be tubular, or have any other complex shape.

[0015] The fluororesin member contains a melt-moldable fluororesin. The fluororesin member may further contain other components in addition to the melt-moldable fluororesin.

[0016] The melt-moldable fluororesin includes at least one selected from the group consisting of copolymers having tetrafluoroethylene (hereinafter also referred to as "TFE") units and copolymers having chlorotrifluoroethylene (hereinafter also referred to as "CTFE") units.

[0017] The melt-moldable fluororesin may further contain other fluorine-containing monomer units in addition to TFE units and CTFE units. The other fluorine-containing monomer is not particularly limited as long as it is a fluorine-containing compound having one polymerizable carbon-carbon double bond.

[0018] Examples of other fluorine-containing monomers include fluoroolefins other than TFE and CTFE, fluorine-containing compounds having a ring structure, compound (1) (hereinafter also referred to as "PAVE"), compound (2) (hereinafter also referred to as "FAE"), compound (3), compound (4), and compound (5). However, the other fluorine-containing monomer is not limited to these examples. The other fluorine-containing monomer may be used alone or in combination of two or more kinds.

[0019] CF2=CFOR f1 ···(1) CH2=CX 1 (CF2) p X 2 ···(2) CF2=CFOR f2 SO2X 3 ···(3) CF2=CFOR f3 CO2X 4 ···(4) CF2=CF(CF2) q OCF=CF2 (5)

[0020] In formula (1), R f1 is a perfluoroalkyl group having 1 to 10 carbon atoms which may have an etheric oxygen atom between the carbon atoms. In formula (2), X 1 is a hydrogen atom or a fluorine atom, p is an integer of 2 to 10, and X 2is a hydrogen atom or a fluorine atom. In formula (3), R f2 is a perfluoroalkylene group having 1 to 10 carbon atoms which may have an etheric oxygen atom between the carbon atoms, and X 3 is a halogen atom or a hydroxyl group. In formula (4), R f3 is a perfluoroalkylene group having 1 to 10 carbon atoms which may have an etheric oxygen atom between the carbon atoms, and X 4 is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. In formula (5), q is 1 or 2.

[0021] Other fluoroolefins include, for example, vinyl fluoride, vinylidene fluoride (hereinafter also referred to as "VdF"), hexafluoropropylene (hereinafter also referred to as "HFP"), and hexafluoroisobutylene. However, the other fluoroolefins are not limited to these examples. The other fluoroolefins may be used alone or in combination of two or more.

[0022] Examples of the fluorine-containing compound having a ring structure include perfluoro(2,2-dimethyl-1,3-dioxole), 2,2,4-trifluoro-5-trifluoromethoxy-1,3-dioxole, and perfluoro(2-methylene-4-methyl-1,3-dioxolane). However, the fluorine-containing compound having a ring structure is not limited to these examples. One type of fluorine-containing compound having a ring structure may be used alone, or two or more types may be used in combination.

[0023] As the other fluorine-containing monomer, other fluoroolefins, PAVE and FAE are preferred from the viewpoint of mechanical properties, and other fluoroolefins and PAVE are more preferred.

[0024] As the other fluoroolefin, HFP is preferred in terms of moldability and mechanical properties.

[0025] Examples of PAVE include CF2=CFOCF2CF3, CF2=CFOCF2CF2CF3, CF2=CFOCF2CF2CF2CF3, and CF2=CFO(CF2)6F. Among these, CF2=CFOCF2CF2CF3 (hereinafter also referred to as "PPVE") is preferred from the standpoint of mechanical properties.

[0026] As FAE, for example, CH2=CF(CF2)2F, CH2=CF(CF2)3F, CH2=CF(CF2)4F, CH2=CF(CF2)5F, CH2=CF(CF2)6F, CH2=CF(CF2)2H, CH2=CF(CF2)3H, CH2=CF(CF2)4H, CH2=CF(CF2)5H, CH2=CF(CF2)6H, CH2=CH(CF2)2F (hereinafter also referred to as "PFEE"), CH2=CH(CF2)3F, CH2=CH(CF2)4F (hereinafter also referred to as "PFBE"), CH2=CH(CF2)5F, CH2=CH(CF2)6F, CH2=CH(CF2)2H, CH2=CH(CF2)3H, CH2=CH(CF2)4H, CH2=CH(CF2)5H, and CH2=CH(CF2)6H. However, the FAE is not limited to these examples. One type of FAE may be used alone, or two or more types may be used in combination.

[0027] The FAE is preferably the compound (2-1). CH2=CH(CF2) p1 X 2 (2-1) In formula (2-1), p1 is 2 to 6, preferably 2 to 4, and X 2 is a hydrogen atom or a fluorine atom.

[0028] As the compound (2-1), PFEE, CH2=CH(CF2)3F, PFBE, CH2=CF(CF2)3H, and CH2=CF(CF2)4H are preferred, and PFBE and PFEE are more preferred.

[0029] The fluororesin may further contain a non-fluorine monomer unit. The non-fluorine monomer is not particularly limited as long as it is a monomer that does not contain a fluorine atom. Examples include olefins such as ethylene, propylene, and 1-butene, and vinyl esters such as vinyl acetate. However, the non-fluorine monomer is not limited to these examples.

[0030] When the fluororesin has a non-fluorine monomer unit, the non-fluorine monomer may be used alone or in combination of two or more. As the non-fluorine monomer, ethylene, propylene, and 1-butene are preferred, and ethylene is particularly preferred, from the viewpoint of improving mechanical properties, etc.

[0031] When the fluororesin is a copolymer having fluorine-containing monomer units and non-fluorine-containing monomer units, the proportion of the fluorine-containing monomer units is preferably 40.0 to 99.5 mol %, more preferably 45 to 99 mol %, based on the total of the fluorine-containing monomer units and non-fluorine-containing monomer units. When the proportion of the fluorine-containing monomer units is equal to or greater than the lower limit of the above-mentioned range, the flame retardancy, chemical resistance, and moldability of the fluororesin are improved. When the proportion of the fluorine-containing monomer units is equal to or less than the upper limit of the above-mentioned range, the mechanical properties are improved.

[0032] The fluororesin member may contain one type of fluorine-containing copolymer as the melt-moldable fluororesin, or may contain two or more types of fluorine-containing copolymers. Examples of the fluorine-containing copolymer include a copolymer having TFE units and ethylene units, a copolymer having CTFE units and ethylene units, a copolymer having TFE units and HFP units, a copolymer having TFE units and PAVE units, a copolymer having TFE units, FAE units and ethylene units, and a copolymer having TFE units, HFP units, FAE units and ethylene units. However, the fluorine-containing copolymer is not limited to these examples.

[0033] When the fluororesin is a copolymer having TFE units and ethylene units, the TFE units preferably account for 30 to 70 mol %, more preferably 40 to 60 mol %, of the total monomer units of the copolymer.

[0034] When the fluororesin is a copolymer having CTFE units and ethylene units, the CTFE units preferably account for 30 to 70 mol %, more preferably 40 to 60 mol %, of the total monomer units of the copolymer.

[0035] When the fluororesin is a copolymer having TFE units, FAE units and ethylene units, the proportions of TFE units are preferably 40 to 64 mol%, FAE units are preferably 1 to 5 mol%, and ethylene units are preferably 35 to 59 mol%, and more preferably 45 to 59 mol%, TFE units are preferably 1 to 4 mol%, and ethylene units are preferably 40 to 54 mol%, based on all monomer units of the copolymer.

[0036] When the fluororesin is a copolymer having TFE units and PAVE units, the TFE units preferably account for 80.0 to 99.5 mol %, more preferably 90 to 95 mol %, of the total monomer units of the copolymer.

[0037] The melting point of the fluororesin is 290°C or lower. Therefore, the fluororesin at the joining surfaces melts sufficiently during vibration welding. The melting point of the fluororesin is preferably 130 to 290°C, more preferably 140 to 280°C, and even more preferably 150 to 260°C. When the melting point of the fluororesin is equal to or higher than the lower limit of the above-mentioned numerical range, the heat resistance is improved and the rigidity at high temperatures is also improved. When the melting point of the fluororesin is equal to or lower than the upper limit of the above-mentioned numerical range, the fluororesin at the joining surfaces melts more easily.

[0038] The glass transition temperature of the fluororesin is 100°C or lower. Therefore, a sufficient fluororesin weld layer can be formed by vibration welding. The glass transition temperature of the fluororesin is preferably -40 to 100°C, more preferably -35 to 90°C, and even more preferably 10 to 80°C. When the glass transition temperature of the fluororesin is equal to or higher than the lower limit of the above-mentioned range, heat resistance is improved and rigidity at high temperatures is also improved. When the glass transition temperature of the fluororesin is equal to or lower than the upper limit of the above-mentioned range, a fluororesin weld layer can be more easily formed.

[0039] The flexural modulus of the fluororesin is 700 MPa or more. Therefore, the energy applied during vibration welding is not easily utilized as elastic force. The flexural modulus of the fluororesin is preferably 700 to 2500 MPa, more preferably 750 to 2300 MPa, and even more preferably 800 to 2000 MPa. When the flexural modulus of the fluororesin is equal to or greater than the lower limit of the above-mentioned numerical range, the fluororesin at the joining surface is more likely to melt. When the flexural modulus of the fluororesin is equal to or less than the upper limit of the above-mentioned numerical range, burrs are more likely to occur during joining.

[0040] The fluororesin has a Rockwell hardness of 30 or more on the R scale. Therefore, the energy applied during vibration welding is not easily utilized as elastic force. The fluororesin has a Rockwell hardness of preferably 30 to 130, more preferably 40 to 120, and even more preferably 50 to 110. When the fluororesin has a Rockwell hardness of 30 to 130, or more than the lower limit of the above-mentioned range, the fluororesin at the joining surface is more easily melted. When the fluororesin has a Rockwell hardness of 30 to 130, or more than the upper limit of the above-mentioned range, burrs are less likely to occur during joining.

[0041] The fluororesin has a dynamic friction coefficient of 0.2 or more. Therefore, sufficient frictional heat is generated during vibration welding. The fluororesin has a dynamic friction coefficient of preferably 0.2 to 1.0, more preferably 0.3 to 0.9, and even more preferably 0.4 to 0.8. When the fluororesin has a dynamic friction coefficient equal to or greater than the lower limit of the above-mentioned range, the fluororesin at the joining surface is more likely to melt. When the fluororesin has a dynamic friction coefficient equal to or less than the upper limit of the above-mentioned range, burrs are less likely to occur during joining.

[0042] The thermal conductivity of the fluororesin is 0.15 W / m·K or higher. Therefore, frictional heat generated during vibration welding is sufficiently transferred to the fluororesin member. As a result, the fluororesin at the joining surface is sufficiently melted. The thermal conductivity of the fluororesin is preferably 0.15 to 4.0 W / m·K, more preferably 0.15 to 3.5 W / m·K, and even more preferably 0.15 to 3.0 W / m·K. When the thermal conductivity of the fluororesin is equal to or higher than the lower limit of the above-mentioned range, the fluororesin at the joining surface is more likely to melt. When the thermal conductivity of the fluororesin is equal to or lower than the upper limit of the above-mentioned range, molding stability is improved.

[0043] The melt viscosity μ1 is measured at a temperature 40°C higher than the melting point of the fluororesin and at a shear rate of 12 / s. The melt viscosity μ1 of fluororesin is 1000 Pa·s or higher. Therefore, the molten fluororesin tends to remain at the joining surface due to the low shear during melt transition. The melt viscosity μ1 is preferably 1,000 to 100,000 Pa·s, more preferably 1,500 to 80,000 Pa·s, and even more preferably 2,000 to 50,000 Pa·s. When the melt viscosity μ1 is equal to or greater than the lower limit of the above-mentioned range, burrs are less likely to occur during joining. When the melt viscosity μ1 is equal to or less than the upper limit of the above-mentioned range, the fluororesin at the joining surface is more likely to melt.

[0044] The melt viscosity μ2 is measured at a temperature 40°C higher than the melting point of the fluororesin and at a shear rate of 1200 / s. The melt viscosity μ2 of fluororesin is 2000 Pa·s or less. Therefore, the molten fluororesin tends to spread across the joint surface during the high shear at the beginning of vibration. The melt viscosity μ2 of the fluororesin is preferably 100 to 2000 Pa·s, more preferably 150 to 1000 Pa·s, and even more preferably 200 to 700 Pa·s. When the melt viscosity μ2 is equal to or greater than the lower limit of the above-mentioned range, burrs are less likely to occur during joining. When the melt viscosity μ2 is equal to or less than the upper limit of the above-mentioned range, the fluororesin at the joining surfaces is more easily welded.

[0045] The melt flow rate of the fluororesin is preferably 1.0 to 40 g / 10 min, more preferably 2.0 to 30 g / 10 min, and even more preferably 2.0 to 20 g / 10 min. When the melt flow rate is equal to or greater than the lower limit of the above-mentioned range, the fluororesin at the joining surface is more easily welded. When the melt flow rate is equal to or less than the upper limit of the above-mentioned range, the mechanical properties of the fluororesin joining member are improved.

[0046] The fluororesin member may contain one type of melt-moldable fluororesin, or may contain two or more types of melt-moldable fluororesin.

[0047] The method for producing the melt-moldable fluororesin is not particularly limited, and it can be produced by a conventional method. For example, the fluororesin can be produced by polymerizing a monomer component containing at least a fluorine-containing monomer. The monomer component may further contain a non-fluorine-containing monomer, if necessary.

[0048] Examples of the polymerization method include bulk polymerization, solution polymerization using an organic solvent (such as a fluorohydrocarbon, a chlorohydrocarbon, a fluorochlorohydrocarbon, an alcohol, or a hydrocarbon), suspension polymerization using an aqueous medium and, if necessary, an appropriate organic solvent, and emulsion polymerization using an aqueous medium and an emulsifier. Of these, solution polymerization is preferred.

[0049] (Other ingredients) The fluororesin member may further contain other components in addition to the melt-moldable fluororesin, provided that the effects of the present invention are not impaired. Examples of such other materials include non-fluorine thermoplastic resins, metal oxides (copper oxide, zinc oxide, iron oxide, nickel oxide, cobalt oxide, etc.), pigments and dyes, sliding agents, conductivity-imparting substances, fiber reinforcements, thermal conductivity-imparting agents, fillers, resins other than fluororesins, modifiers, crystal nucleating agents, foaming agents, foam nucleating agents, crosslinking agents, antioxidants, light stabilizers, and ultraviolet absorbers. However, the other components are not limited to these examples. The other components may be used alone or in combination of two or more.

[0050] The non-fluorine thermoplastic resin is not particularly limited as long as it does not contain a fluorine-containing monomer unit and is melt-moldable. Examples thereof include polycarbonate, polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, polyarylate, polycaprolactone, phenoxy resin, polysulfone, polyethersulfone, polyetherketone, polyetheretherketone, polyetherimide, semi-aromatic polyamide, polyamide 6, polyamide 66, polyamide 11, polyamide 12, polyamide 610, polyphenylene oxide, polyphenylene sulfide, polytetrafluoroethylene, acrylonitrile-styrene-butadiene copolymer, polymethyl methacrylate, polypropylene, polyethylene, polybutadiene, butadiene-styrene copolymer, ethylene-propylene copolymer, ethylene-propylene-diene rubber, styrene-butadiene block copolymer, butadiene-acrylonitrile copolymer, acrylic rubber, styrene-maleic anhydride copolymer, styrene-phenylmaleimide copolymer, aromatic polyester, polyamideimide, and thermoplastic polyimide. However, the non-fluorine thermoplastic resin is not limited to these examples. The non-fluorine thermoplastic resin may be used alone or in combination of two or more kinds.

[0051] The melting point of the non-fluorine thermoplastic resin is not particularly limited, and may be, for example, 100 to 130°C, 150 to 190°C, or 270 to 330°C.

[0052] (Composition of fluororesin components) The proportion of the fluororesin is preferably 50 to 100 mass %, more preferably 70 to 100 mass %, and even more preferably 90 to 100 mass % of the total amount of the fluororesin member. When the proportion of the fluororesin is equal to or greater than the lower limit of the above-mentioned range, the properties of the fluororesin are easily exhibited in the fluororesin member. When the proportion of the other components is equal to or less than the upper limit of the above-mentioned range, the properties of the other components are easily imparted to the fluororesin member.

[0053] When the fluororesin member contains other components, the proportion of the other components is preferably 0 to 30 mass%, more preferably 0 to 25 mass%, and even more preferably 0 to 20 mass% of the total amount of the fluororesin member. When the proportion of the other components is equal to or greater than the lower limit of the above-mentioned range, the properties of the other components are easily imparted to the fluororesin member. When the proportion of the other components is equal to or less than the upper limit of the above-mentioned range, the properties of the fluororesin are easily manifested in the fluororesin member.

[0054] (Fluororesin component manufacturing method) The method for producing the fluororesin member is not particularly limited. For example, the fluororesin member can be produced by molding a fluororesin material containing the above-mentioned melt-moldable fluororesin. The fluororesin material may further contain the above-mentioned other components. Furthermore, the fluororesin material may contain one type of melt-moldable fluororesin, or may contain two or more types of melt-moldable fluororesins.

[0055] The molding method for obtaining the fluororesin member is not particularly limited, and examples thereof include injection molding, extrusion molding, coextrusion molding, blow molding, compression molding, transfer molding, film molding, and press molding. However, the molding method is not limited to these examples.

[0056] (Physical properties of fluororesin bonding materials) The tensile strength of the fluororesin bonding member at the bonding surface by vibration welding is preferably 20 MPa or more, more preferably 30 MPa or more, and even more preferably 40 MPa or more. The upper limit of the tensile strength at the bonding surface is preferably as high as possible, and is not particularly limited, but may be, for example, 60 MPa, 45 MPa, or 30 MPa.

[0057] (Mechanism of action) In the fluororesin bonding member of the present invention, the melt-formable fluororesin contains at least one selected from the group consisting of a copolymer having a TFE unit and a copolymer having a CTFE unit, and the melting point of the fluororesin is 290°C or lower, the glass transition temperature of the melt-formable fluororesin is 100°C or lower, and the flexural modulus of the melt-formable fluororesin is 700 MPa or higher. Therefore, as shown in the examples below, the strength of the bonded part is improved.

[0058] [Method of manufacturing fluororesin bonding members] In the manufacturing method of a fluororesin bonded member, at least two or more fluororesin members are bonded by vibration welding. For example, as shown in Fig. 1, the bonding surface 1a of fluororesin member 1 and the bonding surface 2a of fluororesin member 2 are brought into contact with each other and vibrated in the direction of the contact surfaces, whereby the members are welded together by the frictional heat generated.

[0059] In one example, one fluororesin member 1 may be fixed to a jig and the other fluororesin member 2 may be pressed against it. The fluororesin members 1 and 2 may be vibrated in the direction of their contact surfaces, and the frictional heat generated during the vibration may melt the contact surfaces of the two members. The fluororesin member 2 may then be pressed against the fluororesin member 1 to join them.

[0060] In the case of a copolymer having TFE units and ethylene units, a high welding pressure and a low amplitude tend to result in a large amount of burrs. The welding pressure is the pressure applied to the joining surfaces of the fluororesin members when the fluororesin members are vibrated.

[0061] In the method for manufacturing a fluororesin bonded member of the present invention, the holding pressure when joining the fluororesin members by vibration welding is 5 to 30 MPa, and the holding time when joining the fluororesin members by vibration welding is 3 to 20 seconds. The holding pressure is the pressure used to push the fluororesin members in after vibration has stopped. The holding time is the time required to push the fluororesin members in after vibration has stopped.

[0062] In the manufacturing method of the fluororesin bonded member of the present invention, since the holding pressure and holding time are within a predetermined range, the tensile strength of the bonded surface can be sufficiently maintained even when the welding pressure is set high and the amplitude is set low to suppress the generation of burrs. In addition, the generation of burrs can be suppressed even with copolymers having TFE units and ethylene units. Moreover, the tensile strength of the bonded surface can be sufficiently maintained even with fluororesins other than copolymers having TFE units and ethylene units.

[0063] The holding pressure when joining fluororesin members by vibration welding is 5 to 30 MPa, preferably 10 to 30 MPa, more preferably 10 to 25 MPa, and even more preferably 10 to 20 MPa. When the holding pressure is equal to or greater than the lower limit of the above-mentioned range, the weld strength is improved. When the holding pressure is equal to or less than the upper limit of the above-mentioned range, distortion of the molded body during welding is less likely to occur.

[0064] The holding time when joining fluororesin members by vibration welding is 3 to 20 seconds, preferably 5 to 15 seconds, and more preferably 5 to 10 seconds. When the holding time is equal to or greater than the lower limit of the above-mentioned range, the welding strength is improved. When the holding time is equal to or less than the upper limit of the above-mentioned range, the manufacturing time is shortened.

[0065] The welding pressure and welding time when joining fluororesin members by vibration welding may be appropriately changed or set so as to obtain a desired penetration (melt depth).

[0066] The welding pressure is not particularly limited, but may be, for example, 1 to 30 MPa, 2 to 25 MPa, or 10 to 15 MPa. When the welding pressure is equal to or greater than the lower limit of the above-mentioned numerical range, the welding strength is improved. When the welding pressure is equal to or less than the upper limit of the above-mentioned numerical range, the fluororesin members vibrate sufficiently during welding.

[0067] The welding time is not particularly limited, but may be, for example, 1 to 200 seconds, 5 to 60 seconds, or 10 to 30 seconds. When the welding time is equal to or greater than the lower limit of the above-mentioned numerical range, the welding strength is improved. When the welding time is equal to or less than the upper limit of the above-mentioned numerical range, welding is easily performed while maintaining the overall dimensions of the molded body.

[0068] The frequency used to join fluororesin members by vibration welding is not particularly limited, but may be, for example, 100 to 300 Hz, 180 to 240 Hz, or 200 to 220 Hz. When the frequency is equal to or greater than the lower limit of the above-mentioned range, the weld strength is improved. When the frequency is equal to or less than the upper limit of the above-mentioned range, the generation of burrs is minimized.

[0069] The amplitude when joining fluororesin members by vibration welding is not particularly limited, but may be, for example, 0.5 to 3.0 mm, 1.5 to 2.5 mm, or 1.8 to 2.0 mm. When the amplitude is equal to or greater than the lower limit of the above-mentioned numerical range, the weld strength is improved. When the amplitude is equal to or less than the upper limit of the above-mentioned numerical range, the generation of burrs is minimized.

[0070] The surface roughness of the joining surface of the fluororesin member is preferably 0.01 μm or more, more preferably 0.05 μm or more, and even more preferably 0.1 μm or more. If the surface roughness of the joining surface of the fluororesin member is equal to or greater than the lower limit, sufficient frictional heat is generated during vibration welding. The upper limit of the surface roughness of the joining surface of the fluororesin member is not particularly limited, but may be, for example, 10 μm, 1 μm, or 0.1 μm.

[0071] In the method for producing a fluororesin bonding member, the fluororesin is not particularly limited as long as it is a fluoropolymer having a fluoromonomer unit and is melt-moldable. The fluoromonomer is not particularly limited as long as it is a fluorocompound having one polymerizable carbon-carbon double bond. Details and preferred embodiments of the fluorocompound are the same as those already described.

[0072] In the method for producing a fluororesin bonding member, the melt-moldable fluororesin may be a homopolymer having fluorine-containing monomer units, a copolymer having two or more types of fluorine-containing monomer units, or a copolymer having one or more types of fluorine-containing monomer units and one or more types of non-fluorine-containing monomer units.

[0073] Examples of fluororesin that are homopolymers include polyvinylidene fluoride, polychlorotrifluoroethylene, and polyhexafluoropropylene. Examples of fluororesin that are copolymers include those already described. However, in the method for producing a fluororesin bonding member, the fluororesin that is a copolymer is not limited to a copolymer having a TFE unit or a copolymer having a CTFE unit. In the method for producing a fluororesin bonding member according to a preferred example, the fluororesin may be a copolymer having a TFE unit or a copolymer having a CTFE unit.

[0074] Other details and preferred aspects of the melting point, glass transition temperature, and flexural modulus of the fluororesin are the same as those already explained.

[0075] (Mechanism of action) In the method for producing a fluororesin bonding member of the present invention, the melt-formable fluororesin has a melting point of 290°C or lower, a glass transition temperature of 100°C or lower, and a flexural modulus of 700 MPa or higher. Furthermore, when bonding the fluororesin members by vibration welding, the holding pressure is 5 to 30 MPa, and the holding time is 3 to 20 seconds. Therefore, as shown in the examples below, the strength of the bonded portion is improved.

[0076] [Application] The uses of the fluororesin bonding member are not particularly limited. Examples include ducts, valves, wafer guides, tubes, bottles, and tanks. However, the uses of the fluororesin bonding member are not limited to these examples.

[0077] Although several embodiments have been described above, the present invention is not limited to the exemplary embodiments disclosed in this specification and can be appropriately modified and implemented without departing from the spirit of the invention. The embodiments disclosed in this specification can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. [Example]

[0078] The following examples will explain the embodiments in more detail, but the present invention is not limited to the following examples. Examples 1 to 16 are examples, and Examples 17 to 22 are comparative examples.

[0079] [Measurement method] (Melting point: Tm) Using a differential scanning calorimeter (manufactured by Hitachi High-Tech Science Corporation, product name "DSC7020"), the melting peak was recorded when the polymer was heated at a rate of 10°C / min, and the temperature corresponding to the maximum value was taken as the melting point.

[0080] (glass transition temperature: Tg) Using a dynamic viscoelasticity measuring device (Hitachi High-Tech Science Corporation, product name "DMA7100"), dynamic viscoelasticity was measured at a frequency of 1.0 Hz and a temperature range of 30 to 180° C. The glass transition temperature was measured as the temperature corresponding to the maximum value of the tan δ peak.

[0081] (Rockwell hardness) The Rockwell hardness was measured by the method specified in ASTM D 785. Specifically, the Rockwell hardness was measured under the conditions of ASTM D 785 using a hardness tester (manufactured by Imai Seiki Co., Ltd., product name "Rockwell Type 3R Hardness Tester").

[0082] (flexural modulus) The flexural modulus was measured according to the method specified in ASTM D790. Specifically, the flexural modulus was measured under the conditions of ASTM D790 using a Tensilon universal testing machine (manufactured by A&D Co., Ltd., product name "RTF-1350").

[0083] (dynamic friction coefficient) The dynamic friction coefficient was measured using the Matsubara friction measurement method with SUS as the mating material. Specifically, the dynamic friction coefficient was measured using a friction and wear tester (manufactured by TSE Co. Ltd., product name "FRT-2-EAA") under conditions conforming to JIS K-721.

[0084] (thermal conductivity) The thermal conductivity was measured according to the method specified in ASTM C177. Specifically, the thermal conductivity was measured using a steady-state thermal conductivity measuring device (manufactured by ULVAC-RIKO, product name "GH-1") at a set temperature of 30°C and a test thickness of 2.98 mm.

[0085] (Melt viscosity: μ1, μ2) The melt viscosity of the fluororesin was measured using a capillary rheometer (manufactured by Toyo Seiki Seisakusho Co., Ltd., product name "Capilograph F-1") under the conditions of a preheating time of 5 minutes, a capillary diameter of 1 mm, and a capillary length of 10 mm. The temperature was the melting point of the fluororesin + 40°C, and the shear rates were 12 / s and 1200 / s.

[0086] (Surface roughness: Ra) For the measurement of surface roughness, a 10 cm × 10 cm pressed sheet was used. The surface roughness of the pressed sheet was then measured using a surface roughness and contour shape measuring instrument (manufactured by Kanaden Corporation, product name "Surfcom NEX100").

[0087] (tensile strength, tensile strength retention rate) The fluororesin bonding members of each example were punched out using a dumbbell mold to obtain dumbbell-shaped test pieces. The fluororesin bonding members were punched out so that the welded portion was positioned in the center of the dumbbell. These test pieces were subjected to a tensile test using a Tensilon testing machine at a tensile speed of 50 to 200 mm / min to measure the tensile strength of the vibration-welded bonded surface. Separately, test pieces were obtained by punching out the fluororesin bonding members of each example using a dumbbell mold so that the bonding surface was not included in the center of the dumbbell. Tensile tests were conducted on these test pieces under the same conditions, and the tensile strength of the surfaces other than the bonding surface was measured. The tensile strength retention rate was calculated by dividing the tensile strength of the vibration-welded bonding surface by the tensile strength of the surfaces other than the bonding surface.

[0088] [Raw materials] ETFE1: Copolymer having TFE units and ethylene units (TFE units / ethylene units / C4 = 54 / 46 / 0.9 (molar ratio), melt flow rate: 5 g / 10 min) ETFE2: Copolymer having TFE units and ethylene units (TFE units / ethylene units / C4 = 54 / 46 / 1.4 (molar ratio), melt flow rate: 30 g / 10 min) ETFE3: Copolymer having TFE units and ethylene units (TFE units / ethylene units = 60 / 40 / 3.3 (molar ratio), melt flow rate: 25 g / 10 min) ETFE4: Copolymer having TFE units and ethylene units (TFE units / ethylene units = 60 / 40 / 3.3 (molar ratio), melt flow rate: 35 g / 10 min) ETFE5: Copolymer having TFE units and ethylene units (TFE units / ethylene units / HFP / C4 / IAH=48 / 44 / 8 / 0.8 / 0.4 (molar ratio), melt flow rate: 4 g / 10 min) ETFE6: A compound of a copolymer having TFE units and ethylene units (TFE units / ethylene units = 54 / 46 / 1.4 (molar ratio), melt flow rate: 11 g / 10 min) and carbon black, the mass of carbon black being 20% ​​by mass of the total mass of the copolymer and carbon black PVdF1: homopolymer consisting of VdF units (melt flow rate: 10 g / 10 min) PCTFE1: homopolymer consisting of CTFE units (melt flow rate: 10 g / 10 min) ECTFE1: A copolymer having CTFE units and ethylene units (CTFE units / ethylene units = 53 / 47 (molar ratio), melt flow rate: 10 g / 10 min) PFA1: Copolymer having TFE units and PPVE units (TFE units / PPVE units=98.5 / 1.5 (molar ratio), melt flow rate: 2 g / 10 min) FEP1: Copolymer having TFE units and HFP units (TFE units / HFP units / PPVE units=91 / 8 / 0.4 (molar ratio), melt flow rate: 25 g / 10 min)

[0089] [Example 1-Example 22] In Examples 1 to 22, a vibration welder GVX-2H manufactured by Emerson Japan Co., Ltd. was used.

[0090] The fluororesin members were prepared by molding them into a rectangular parallelepiped shape with dimensions of 100 mm high x 100 mm wide x 3 mm deep using an injection molding machine. Two rectangular fluororesin members were used and placed in a jig for a vibration welding machine so that the joining surfaces were the top and bottom surfaces, each measuring 100 mm wide x 3 mm deep. The two fluororesin members were then joined by vibration welding under the conditions shown in Table 1 to obtain an I-shaped fluororesin joined member.

[0091] [Table 1]

[0092] [Table 2]

[0093] In Examples 1 to 16, the tensile strength of the joining surface was high and the fluororesin members were joined with sufficient strength, whereas in Examples 17 to 22, the fluororesin members were not joined with sufficient strength. [Industrial Applicability]

[0094] According to the present invention, a fluororesin bonding member having improved bond strength and a method for manufacturing the same are provided. [Explanation of symbols]

[0095] 1 Fluorine resin material 2 Fluorine resin materials 5 Fluorine resin bonding materials

Claims

1. A fluororesin bonded member in which at least two or more fluororesin members are bonded by vibration welding, the fluororesin member contains a melt-moldable fluororesin, the melt-moldable fluororesin comprises at least one selected from the group consisting of a copolymer having a unit based on tetrafluoroethylene and a copolymer having a unit based on chlorotrifluoroethylene, The melting point of the melt-moldable fluororesin is 290°C or less, The melt-moldable fluororesin has a glass transition temperature of 100°C or less, A fluororesin joining member, wherein the melt-moldable fluororesin has a flexural modulus of 700 MPa or more.

2. 2. The fluororesin joining member according to claim 1, wherein the melt-moldable fluororesin has a Rockwell hardness of 30 or more on the R scale.

3. 2. The fluororesin joining member according to claim 1, wherein the melt-moldable fluororesin has a dynamic friction coefficient of 0.2 or more.

4. 3. The fluororesin joining member according to claim 1, wherein the melt-moldable fluororesin has a thermal conductivity of 0.15 W / m·K or more.

5. 3. The fluororesin bonding member according to claim 1, wherein the melt viscosity of the melt-formable fluororesin is 1000 Pa s or more, measured under conditions where the melt viscosity is 40° C. higher than the melting point of the melt-formable fluororesin and the shear rate is 12 / s.

6. 3. The fluororesin bonding member according to claim 1, wherein the melt viscosity of the melt-formable fluororesin is 2000 Pa s or less, measured under conditions where the melt viscosity is 40° C. higher than the melting point of the melt-formable fluororesin and the shear rate is 1200 / s.

7. 3. The fluororesin joining member according to claim 1, wherein the melt-moldable fluororesin contains a copolymer having units based on tetrafluoroethylene and units based on ethylene.

8. A method for manufacturing a fluororesin bonded member, in which at least two or more fluororesin members are bonded by vibration welding, comprising: the fluororesin member contains a melt-moldable fluororesin, The melting point of the melt-moldable fluororesin is 290°C or less, The melt-moldable fluororesin has a glass transition temperature of 100°C or less, The melt-moldable fluororesin has a flexural modulus of 700 MPa or more, The manufacturing method includes: setting a holding pressure of 5 to 30 MPa when joining the fluororesin members by vibration welding; and setting a holding time of 3 to 20 seconds when joining the fluororesin members by vibration welding.

9. The method according to claim 8, wherein the melt-moldable fluororesin has a Rockwell hardness of 30 or more on the R scale.

10. 10. The manufacturing method according to claim 8, wherein the surface roughness of the joining surface of the fluororesin member is 0.01 [mu]m or more.

11. The method according to claim 8 or 9, wherein the melt-moldable fluororesin has a dynamic friction coefficient of 0.2 or more.

12. The method according to claim 8 or 9, wherein the melt-moldable fluororesin has a thermal conductivity of 0.15 W / m·K or more.

13. 10. The production method according to claim 8 or 9, wherein the melt viscosity of the melt-formable fluororesin is 1000 Pa s or more, measured under conditions where the temperature is 40°C higher than the melting point of the melt-formable fluororesin and the shear rate is 12 / s.

14. 10. The production method according to claim 8 or 9, wherein the melt viscosity of the melt-formable fluororesin is 2000 Pa s or less, measured under conditions where the temperature is 40°C higher than the melting point of the melt-formable fluororesin and the shear rate is 1200 / s.

15. 10. The production method according to claim 8 or 9, wherein the melt-moldable fluororesin comprises at least one selected from the group consisting of a copolymer having units based on tetrafluoroethylene and a copolymer having units based on chlorotrifluoroethylene.

16. The method according to claim 15, wherein the melt-processable fluororesin comprises a copolymer having units based on tetrafluoroethylene and units based on ethylene.

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